阅读说明：本技术 混合动力车辆及其控制方法 (Hybrid vehicle and control method thereof ) 是由 野濑勇喜 小林正明 于 2020-07-23 设计创作，主要内容包括：本发明涉及混合动力车辆及其控制方法。所述混合动力车辆包括：多缸发动机；排气净化装置,包括净化来自该多缸发动机的排气的催化剂；电动机；及控制装置,在多缸发动机的负荷运转中被要求了催化剂的升温的情况下,执行使向至少任一个气缸的燃料供给停止且使剩余的气缸中的空燃比成为浓空燃比的催化剂升温控制,并且以补偿因催化剂升温控制的执行而不足的驱动力的方式控制电动机,在催化剂升温控制的执行中,在排气净化装置的温度成为判定阈值以上后使上述剩余的气缸的至少任一个中的空燃比向稀侧变化。(The invention relates to a hybrid vehicle and a control method thereof. The hybrid vehicle includes: a multi-cylinder engine; an exhaust gas purification device including a catalyst that purifies exhaust gas from the multi-cylinder engine; an electric motor; and a control device that, when a temperature rise of the catalyst is requested during a load operation of the multi-cylinder engine, executes catalyst temperature rise control for stopping fuel supply to at least one of the cylinders and making the air-fuel ratio in the remaining cylinders rich, and controls the electric motor so as to compensate for insufficient driving force resulting from execution of the catalyst temperature rise control, wherein, during execution of the catalyst temperature rise control, the air-fuel ratio in at least one of the remaining cylinders is changed to a lean side after the temperature of the exhaust gas purification device becomes equal to or greater than a determination threshold.)

1. A hybrid vehicle includes a multi-cylinder engine; an exhaust gas purification device including a catalyst that purifies exhaust gas from the multi-cylinder engine; an electric motor; and a power storage device that supplies and receives electric power to and from the electric motor, at least one of the multi-cylinder engine and the electric motor outputting driving force to wheels,

the hybrid vehicle includes a control device that executes catalyst temperature increase control for stopping fuel supply to at least one of the cylinders and making an air-fuel ratio in remaining cylinders other than the at least one of the cylinders rich when temperature increase of the catalyst is requested during load operation of the multi-cylinder engine, and controls the electric motor so as to compensate for insufficient driving force due to execution of the catalyst temperature increase control, wherein the control device changes the air-fuel ratio in at least one of the remaining cylinders to a lean side after a temperature of the exhaust gas purification device becomes equal to or higher than a predetermined determination threshold during execution of the catalyst temperature increase control.

2. The hybrid vehicle according to claim 1, wherein,

the control device changes the air-fuel ratio in the remaining cylinders to a lean side after the temperature of the exhaust gas purification device becomes equal to or higher than a 1 st determination threshold during execution of the catalyst temperature increase control, and stops fuel supply to at least any one of the remaining cylinders on condition that the driving force insufficient due to execution of the catalyst temperature increase control can be compensated by the motor after the temperature of the exhaust gas purification device becomes equal to or higher than a 2 nd determination threshold higher than the 1 st determination threshold.

3. The hybrid vehicle according to claim 1, wherein,

the control device stops the fuel supply to at least any one of the remaining cylinders and changes the air-fuel ratio to a lean side in the cylinder in which the fuel supply to the remaining cylinder is not stopped, on the condition that the driving force insufficient due to the execution of the catalyst temperature increase control can be compensated for by the motor, after the temperature of the exhaust gas purification device becomes equal to or higher than the determination threshold during the execution of the catalyst temperature increase control.

4. The hybrid vehicle according to claim 2 or 3, wherein,

the control device sets the air-fuel ratio in the cylinder to which the fuel is supplied to a rich air-fuel ratio when the temperature of the exhaust gas purification device becomes lower than a predetermined temperature after changing the air-fuel ratio in at least any one of the remaining cylinders to a lean side.

5. The hybrid vehicle according to claim 4, wherein,

the control device reduces the number of cylinders in which the fuel supply is stopped when the temperature of the exhaust gas purification device becomes lower than the predetermined temperature after changing the air-fuel ratio to a lean side in at least any one of the remaining cylinders.

6. The hybrid vehicle according to any one of claims 2 to 5,

the control device executes the catalyst temperature increasing control so that fuel is supplied to at least 1 of the cylinders after fuel supply to any one of the cylinders is stopped.

7. The hybrid vehicle according to any one of claims 1 to 6,

the exhaust gas purification apparatus includes a particulate trap.

8. A control method for a hybrid vehicle including a multi-cylinder engine, an exhaust gas purification device, an electric motor, and an electric storage device that transmits/receives electric power to/from the electric motor, wherein the exhaust gas purification device includes a catalyst that purifies exhaust gas from the multi-cylinder engine, and at least one of the multi-cylinder engine and the electric motor outputs driving force to wheels of the vehicle, wherein,

when the temperature rise of the catalyst is requested during the load operation of the multi-cylinder engine, a catalyst temperature rise control is executed that stops the supply of fuel to at least one of the cylinders and makes the air-fuel ratio in the remaining cylinders other than the at least one of the cylinders rich, and the electric motor is controlled so as to compensate for insufficient driving force due to the execution of the catalyst temperature rise control, wherein the air-fuel ratio in at least one of the remaining cylinders is changed to a lean side after the temperature of the exhaust gas purification apparatus becomes equal to or higher than a predetermined determination threshold during the execution of the catalyst temperature rise control.

Technical Field

The present disclosure relates to a hybrid vehicle including a multi-cylinder engine, an exhaust gas purification device including a catalyst that purifies exhaust gas from the multi-cylinder engine, and an electric motor, and a control method thereof.

Background

Conventionally, there is known a control device that executes catalyst temperature raising control (dither control) for setting the air-fuel ratio of a part of cylinders (rich cylinders) to a rich air-fuel ratio and setting the air-fuel ratio of a part of cylinders (lean cylinders) to a lean air-fuel ratio when the SOx poisoning amount of a catalyst device disposed in an exhaust passage of an internal combustion engine exceeds a predetermined value (for example, refer to japanese patent application laid-open No. 2004-218541). The control device makes the rich degree of the rich cylinder and the lean degree of the lean cylinder different in the initial stage and the subsequent stage of the start of the temperature raising control. The control device changes the rich level and the lean level with the elapse of time from the start of the temperature increase control so that the rich level and the lean level at the initial start of the temperature increase control become smaller. This can suppress the occurrence of misfire in the lean cylinder and raise the temperature of the catalyst device.

Further, conventionally, a control device is known which sequentially executes an ignition timing retard control, a fuel cut/rich control, and a lean/rich control (a dither control) as a catalyst temperature rise control for warming up a catalyst device for purifying exhaust gas from an internal combustion engine (for example, refer to japanese patent application laid-open publication No. 2011-. The ignition timing retard control retards the ignition timing to warm up the catalyst device with high-temperature exhaust gas. The fuel cut/rich control causes a cylinder in which fuel injection is stopped in a state where the intake valve and the exhaust valve are operated and a cylinder in which fuel is injected so that the air-fuel ratio becomes a rich air-fuel ratio to alternately appear. The fuel cut/rich control is executed for about 3 seconds after the temperature of the catalyst inlet reaches the 1 st temperature by the ignition timing retard control. Thereby, oxygen and the unburned gas are fed to the catalyst device, and the catalyst device is warmed up by the reaction heat of the oxidation reaction. After the temperature at the catalyst inlet reaches the 2 nd temperature higher than the 1 st temperature, lean/rich control is executed until the temperature at the catalyst outlet reaches the 2 nd temperature.

Further, conventionally, as a control device of a hybrid vehicle including an internal combustion engine and an electric motor, there is known a control device which stops fuel supply to each cylinder of the internal combustion engine when a required power for the internal combustion engine becomes lower than a threshold value, and controls the electric motor so as to output a torque based on a required torque and a correction torque at a timing when a correction start time has elapsed from a fuel cut start timing. The control device predicts the shortest time and the longest time from the fuel cut start timing to the start of generation of a torque shock due to the fuel cut on the basis of the rotation speed and the number of cylinders of the internal combustion engine, and sets the time between the shortest time and the longest time as the correction start time. The correction torque is determined so as to cancel out a torque shock acting on the drive shaft.

Disclosure of Invention

However, even if the conventional catalyst temperature increase control as described above is executed, when the ambient temperature is low or the required temperature for the catalyst temperature increase control is high, sufficient air, that is, oxygen, may not be fed to the catalyst device to sufficiently increase the temperature of the catalyst device. Further, according to the conventional catalyst temperature rise control, it is not easy to introduce oxygen into the exhaust gas purification apparatus in an amount required for regeneration of the catalyst and the particulate trap of the exhaust gas purification apparatus. On the other hand, when the catalyst temperature increase control is executed during the load operation of the internal combustion engine, it is necessary to suppress deterioration of drivability of the vehicle on which the internal combustion engine is mounted.

Accordingly, a main object of the present disclosure is to supply a sufficient amount of oxygen to an exhaust gas purification device while raising the temperature of a catalyst of the exhaust gas purification device sufficiently and quickly while suppressing deterioration of drivability of a vehicle during load operation of a multi-cylinder engine.

A hybrid vehicle of the present disclosure includes a multi-cylinder engine, an exhaust gas purification device including a catalyst purifying exhaust gas from the multi-cylinder engine, an electric motor, and an electric storage device supplying and receiving electric power to and from the electric motor, wherein at least one of the multi-cylinder engine and the electric motor outputs driving force to wheels, wherein the hybrid vehicle includes a control device that executes catalyst temperature increase control for stopping fuel supply to at least any one of cylinders and making an air-fuel ratio in remaining cylinders other than the at least any one of cylinders rich when temperature increase of the catalyst is requested during load operation of the multi-cylinder engine, and controls the electric motor so as to compensate for insufficient driving force due to execution of the catalyst temperature increase control, and wherein the control device controls the electric motor during execution of the catalyst temperature increase control, and changing the air-fuel ratio of at least one of the remaining cylinders to a lean side after the temperature of the exhaust gas purification apparatus becomes equal to or higher than a predetermined determination threshold.

In a control method of a hybrid vehicle according to the present disclosure, the hybrid vehicle includes a multi-cylinder engine, an exhaust gas purification device, an electric motor, and an electric storage device that gives and receives electric power to and from the electric motor, the exhaust gas purification device includes a catalyst that purifies exhaust gas from the multi-cylinder engine, and at least one of the multi-cylinder engine and the electric motor outputs driving force to wheels of the multi-cylinder engine, wherein when temperature rise of the catalyst is requested during load operation of the multi-cylinder engine, catalyst temperature rise control is executed that stops fuel supply to at least any one of cylinders and sets an air-fuel ratio in remaining cylinders other than the at least any one cylinder to a rich air-fuel ratio, and the electric motor is controlled so as to compensate for insufficient driving force due to execution of the catalyst temperature rise control, and changing the air-fuel ratio of at least one of the remaining cylinders to a lean side after the temperature of the exhaust gas purification device becomes equal to or higher than a predetermined determination threshold.

Drawings

The features, advantages and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

fig. 1 is a schematic configuration diagram showing a hybrid vehicle of the present disclosure.

Fig. 2 is a schematic configuration diagram showing a multi-cylinder engine included in the hybrid vehicle of fig. 1.

Fig. 3 is a flowchart illustrating a particulate trap regeneration necessity determining routine executed in the hybrid vehicle of fig. 1.

Fig. 4 is a flowchart illustrating a catalyst temperature increase control routine executed in the hybrid vehicle of fig. 1.

Fig. 5 is a flowchart illustrating a catalyst temperature increase control routine executed in the hybrid vehicle of fig. 1.

Fig. 6A and 6B are flowcharts illustrating a drive control routine executed in the hybrid vehicle of fig. 1.

Fig. 7 is an explanatory diagram showing a relationship between torque output from the multi-cylinder engine and ignition timing.

Fig. 8 is a time chart showing the operating state of the multi-cylinder engine and the change in temperature of the particulate trap during execution of the routine shown in fig. 4 to 6B.

Fig. 9 is a schematic configuration diagram showing another hybrid vehicle of the present disclosure.

Fig. 10 is a schematic configuration diagram showing still another hybrid vehicle of the present disclosure.

Fig. 11 is a schematic configuration diagram showing another hybrid vehicle of the present disclosure.

Fig. 12 is a schematic configuration diagram showing still another hybrid vehicle of the present disclosure.

Detailed Description

Next, a mode for carrying out the disclosed invention will be described with reference to the drawings.

Fig. 1 is a schematic configuration diagram showing a hybrid vehicle 1 of the present disclosure. The hybrid vehicle 1 shown in the drawing includes a multi-cylinder engine (hereinafter, simply referred to as "engine") 10 including a plurality of (for example, 4 in the present embodiment) cylinders (combustion chambers) 11, a single-pinion planetary gear 30, motor generators MG1 and MG2 each of which is a synchronous generator motor (three-phase alternating-current motor), a power storage device (battery) 40, an electric power control device (hereinafter, referred to as "PCU") 50 connected to the power storage device 40 and driving the motor generators MG1 and MG2, an electronically controlled hydraulic brake device 60 capable of applying a friction braking force to wheels W, and a hybrid electronic control unit (hereinafter, referred to as "HVECU") 70 controlling the entire vehicle.

The engine 10 is an in-line gasoline engine (internal combustion engine) that converts reciprocating motion of a piston (not shown) associated with combustion of an air-fuel mixture of hydrocarbon-based fuel and air in a plurality of cylinders 11 into rotational motion of a crankshaft (output shaft) 12. As shown in fig. 2, engine 10 includes an intake pipe 13, an intake manifold 13m, a throttle valve 14, a plurality of intake valves and a plurality of exhaust valves, not shown, a plurality of port injection valves 15p, a plurality of in-cylinder injection valves 15d, a plurality of ignition plugs 16, an exhaust manifold 17m, and an exhaust pipe 17. The throttle valve 14 is an electronically controlled throttle valve capable of changing the passage area in the intake pipe 13. The intake manifold 13m is connected to an intake pipe 13 and intake ports of the cylinders 11. Each port injection valve 15p injects fuel into the corresponding intake port, and each in-cylinder injection valve 15d directly injects fuel into the corresponding cylinder 11. The exhaust manifold 17m is connected to an exhaust port of each cylinder 11 and an exhaust pipe 17.

Further, the engine 10 includes a low-pressure delivery pipe DL connected to a feed pump (low-pressure pump) Pf via a low-pressure fuel feed pipe LL, and a high-pressure delivery pipe DH connected to a feed pump (high-pressure pump) Ps via a high-pressure fuel feed pipe LH. The fuel inlet of each port injection valve 15p is connected to low-pressure delivery pipe DL, and the fuel inlet of each in-cylinder injection valve 15d is connected to high-pressure delivery pipe DH. The supply pump Pf is an electric pump including a motor driven by electric power from an auxiliary battery, not shown. The fuel from the supply pump Pf is accumulated in the low-pressure delivery pipe DL, and is supplied from the low-pressure delivery pipe DL to each port injection valve 15 p. The supply pump Ps is, for example, a piston pump (mechanical pump) driven by the engine 10. The high-pressure fuel from the supply pump Ps is accumulated in the high-pressure delivery pipe DH, and is supplied from the high-pressure delivery pipe DH to each in-cylinder injection valve 15 d.

As shown in fig. 2, engine 10 includes evaporated fuel treatment device 110 that introduces evaporated fuel generated in fuel tank Tk that accumulates fuel into intake manifold 13 m. The evaporated fuel treatment device 110 includes a canister 111 having an adsorbent (activated carbon) for adsorbing the evaporated fuel in the fuel tank Tk, a vapor passage Lv connecting the fuel tank Tk and the canister 111, a purge passage Lp connecting the canister 111 and the intake manifold 13m, and a purge valve (vacuum switching valve) Vsv provided in the purge passage Lp. In the present embodiment, the purge valve Vsv is a control valve capable of adjusting the valve opening degree.

Further, the engine 10 includes, as exhaust gas purification devices, an upstream side purification device 18 and a downstream side purification device 19 incorporated in the exhaust pipe 17, respectively. The upstream side purification device 18 includes an NOx storage type exhaust purification catalyst (three-way catalyst) 180 that purifies harmful components such as CO (carbon monoxide), HC, and NOx in the exhaust gas from each cylinder 11 of the engine 10. The downstream-side purification device 19 is disposed downstream of the upstream-side purification device 18, and includes a particulate trap (GPF)190 that traps particulate matter (particulates) in the exhaust gas. In the present embodiment, the particulate trap 190 carries an NOx storage type exhaust purification catalyst (three-way catalyst).

The engine 10 as described above is controlled by an engine electronic control unit (hereinafter, referred to as "engine ECU") 100. Engine ECU100 includes a microcomputer having a CPU, ROM, RAM, input/output interface, and the like, not shown, various drive circuits, various logic ICs, and the like, and executes intake air amount control, fuel injection control, ignition timing control, purge control for controlling the purge amount of evaporated fuel by evaporated fuel treatment device 110 (purge valve Vsv), and the like of engine 10. Further, engine ECU100 obtains detected values of crank angle sensor 90, water temperature sensor 91, air flow meter 92, an intake pressure sensor, a throttle position sensor, an upstream air-fuel ratio sensor 95, a downstream air-fuel ratio sensor 96, a differential pressure sensor 97, an upstream catalyst temperature sensor 98, a downstream catalyst temperature sensor 99, and the like, which are not shown, via an input port, which is not shown.

The crank angle sensor 90 detects a rotational position of the crankshaft 12 (crankshaft position). The water temperature sensor 91 detects the cooling water temperature Tw of the engine 10. The airflow meter 92 detects an intake air amount GA of the engine 10. The intake pressure sensor detects the pressure in the intake pipe 13, that is, the intake pressure. The throttle position sensor detects a spool position (throttle position) of the throttle valve 14. The upstream air-fuel ratio sensor 95 detects an upstream air-fuel ratio AFf, which is the air-fuel ratio of the exhaust gas flowing into the upstream purification device 18. The downstream air-fuel ratio sensor 96 detects a downstream air-fuel ratio AFr, which is the air-fuel ratio of the exhaust gas flowing into the downstream purification device 19. The differential pressure sensor 97 detects a differential pressure Δ P of the exhaust gas on the upstream side and the downstream side of the downstream purification device 19, i.e., the particulate trap 190. The upstream side catalyst temperature sensor 98 detects the temperature (catalyst temperature) Tct of the exhaust purification catalyst 180 that is the upstream side purification device 18. The downstream-side catalyst temperature sensor 99 detects the temperature (catalyst temperature) Tpf of the downstream-side purification device 19, i.e., the particulate trap 190.

Engine ECU100 calculates rotation speed Ne of engine 10 (crankshaft 12) based on the crank position from crank angle sensor 90. Further, engine ECU100 calculates (estimates) a deposition amount Dpm of particulate matter in particulate trap 190 of downstream purifier 19 at predetermined time intervals by either one of an operation history method and a differential pressure method, based on the operating state of engine 10 and the like. When the differential pressure method is used, engine ECU100 calculates a deposition amount Dpm based on a differential pressure Δ P detected by differential pressure sensor 97, that is, a pressure loss in particulate trap 190 due to deposition of particulate matter. When the operation history is used, engine ECU100 calculates the deposit amount Dpm (present value) by adding the estimated increase amount (positive value) or the estimated decrease amount (negative value) of the particulate matter to the previous value of the deposit amount Dpm according to the operating state of engine 10. The estimated increase amount of the particulate matter is calculated as, for example, the product of the estimated discharge amount of the particulate matter, the discharge coefficient, and the collection rate of the particulate trap 190, which are calculated based on the rotation speed Ne, the load factor, and the cooling water temperature Tw of the engine 10. The estimated amount of decrease in particulate matter is calculated as, for example, the product of the amount of combustion of particulate matter calculated from the previous value of the deposition amount Dpm, the inflow air flow rate, and the temperature Tpf of the particulate trap 190 and the correction coefficient.

Further, the engine 10 may be a diesel engine including a diesel particulate trap (DPF) or an LPG engine. The temperatures Tct, Tpf of the exhaust purification catalyst 180 and the particulate trap 190 may be estimated based on the intake air amount GA, the rotation speed Ne, the temperature of the exhaust GAs, the upstream air-fuel ratio AFf, the downstream air-fuel ratio AFr, and the like.

The planetary gear 30 is a differential rotation mechanism including a sun gear (1 st element) 31, a ring gear (2 nd element) 32, and a carrier (3 rd element) 34 that rotatably supports a plurality of pinion gears 33. As shown in fig. 1, a rotor of motor generator MG1 is coupled to sun gear 31, and crankshaft 12 of engine 10 is coupled to carrier 34 via damper mechanism 24. The ring gear 32 is integrated with a counter drive gear 35 as an output member, and both rotate coaxially and integrally.

The counter drive gear 35 is coupled to the left and right wheels (drive wheels) W via a counter driven gear 36 that meshes with the counter drive gear 35, a final drive gear (drive pinion) 37 that rotates integrally with the counter driven gear 36, a final driven gear (differential ring gear) 39r that meshes with the final drive gear 37, a differential gear 39, and a drive shaft DS. Thus, the planetary gear 30, the gear train from the counter drive gear 35 to the final driven gear 39r, and the differential gear 39 constitute a transaxle 20 that transmits a part of the output torque of the engine 10 as a power generation source to the wheels W and couples the engine 10 and the motor generator MG1 to each other.

Further, a drive gear 38 is fixed to a rotor of motor generator MG 2. The drive gear 38 has a smaller number of teeth than the counter driven gear 36, and meshes with the counter driven gear 36. Thus, motor generator MG2 is coupled to the left and right wheels W via drive gear 38, counter driven gear 36, final drive gear 37, final driven gear 39r, differential gear 39, and drive shaft DS.

Motor generator MG 1(2 nd electric motor) mainly operates as a generator that converts at least a part of the power from engine 10 in the load running mode into electric power. Motor generator MG2 mainly operates as an electric motor that is driven by at least one of the electric power from power storage device 40 and the electric power from motor generator MG1 to generate a drive torque on drive shaft DS. That is, in hybrid vehicle 1, motor generator MG2 as a power generation source functions as a power generation device that outputs drive torque (drive force) to wheels W attached to drive shaft DS together with engine 10. Motor generator MG2 outputs regenerative braking torque at the time of braking of hybrid vehicle 1. The motor generators MG1 and MG2 can exchange electric power with the power storage device 40 via the PCU50 and exchange electric power with each other via the PCU 50.

The power storage device 40 is, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery. The power storage device 40 is managed by a power supply management electronic control device (hereinafter referred to as "power supply management ECU") 45 including a microcomputer having a CPU, a ROM, a RAM, an input/output interface, and the like, which are not shown. Power supply management ECU45 derives SOC (charging rate), allowable charging power Win, allowable discharging power Wout, and the like of power storage device 40 based on inter-terminal voltage VB from the voltage sensor of power storage device 40, charging/discharging current IB from the current sensor, battery temperature Tb from temperature sensor 47 (see fig. 1), and the like.

PCU50 includes 1 st inverter 51 that drives motor generator MG1, 2 nd inverter 52 that drives motor generator MG2, a step-up converter (voltage conversion means) 53 capable of stepping up electric power from power storage device 40 and stepping down electric power from the motor generator MG1, MG2 side, and the like. The PCU50 is controlled by a motor electronic control device (hereinafter referred to as "MGECU") 55 including a microcomputer having a CPU, a ROM, a RAM, an input/output interface, and the like (not shown), various drive circuits, various logic ICs, and the like. MGECU55 obtains command signals from HVECU70, pre-boost voltage and post-boost voltage of boost converter 53, detection values of a resolver, not shown, that detects rotational positions of rotors of motor generators MG1 and MG2, phase currents to be applied to motor generators MG1 and MG2, and the like. The MGECU55 performs switching control of the 1 st and 2 nd inverters 51 and 52 and the boost converter 53 based on these signals and the like. MGECU55 calculates rotation speeds Nm1 and Nm2 of rotors of motor generators MG1 and MG2 based on the detection value of the resolver.

The hydraulic brake device 60 includes a master cylinder, a plurality of brake pads that sandwich brake discs attached to the respective wheels W and apply braking torque (frictional braking torque) to the corresponding wheels, a plurality of wheel cylinders (all of which are not shown) that drive the corresponding brake pads, a hydraulic brake actuator 61 that supplies hydraulic pressure to the respective wheel cylinders, a brake electronic control unit (hereinafter, referred to as "brake ECU") 65 that controls the brake actuator 61, and the like. The brake ECU65 includes a microcomputer having a CPU, ROM, RAM, input/output interface, and the like, which are not shown. The brake ECU65 acquires a command signal from the HVECU70, a brake pedal stroke BS (an amount of depression of the brake pedal 64) detected by the brake pedal stroke sensor 63, a vehicle speed V detected by a vehicle speed sensor (not shown), and the like. The brake ECU65 controls the brake actuator 61 based on these signals and the like.

The HVECU70 includes a microcomputer having a CPU, a ROM, a RAM, an input/output interface, and the like, not shown, various drive circuits, various logic ICs, and the like. The HVECU70 exchanges information (communication frames) with the ECUs 100, 45, 55, 65, etc. via a common communication line (multiplex communication bus), not shown, that is, a CAN bus including 2 communication lines (harnesses) of Lo and Hi. The HVECU70 and the ECUs 100, 45, 55, and 65 are connected to each other via a dedicated communication line (local communication bus) that is a CAN bus including 2 communication lines (harnesses) of Lo and Hi. The HVECU70 exchanges information (communication frames) with each of the ECUs 100, 45, 55, 65 via corresponding dedicated communication lines. The HVECU70 acquires a signal from a not-shown start switch for instructing the system start of the hybrid vehicle 1, the shift position SP of the shift lever 82 detected by the shift position sensor 81, the accelerator opening Acc (the amount of depression of the accelerator pedal 84) detected by the accelerator pedal position sensor 83, the vehicle speed V detected by a not-shown vehicle speed sensor, the crank position from the crank angle sensor 90 of the engine 10, and the like. Further, HVECU70 obtains SOC (charging rate) of power storage device 40 from power supply management ECU45, allowable charging electric power Win, allowable discharging electric power Wout, rotation speeds Nm1 and Nm2 of motor generators MG1 and MG2 from MGECU55, and the like.

The HVECU70 derives a required torque Tr (including a required braking torque) to be output to the drive shaft DS corresponding to the accelerator opening Acc and the vehicle speed V, from a required torque setting map (not shown) during running of the hybrid vehicle 1. Then, the HVECU70 sets the required traveling power Pd (═ Tr × Nds) required for traveling of the hybrid vehicle 1, based on the required torque Tr and the rotation speed Nds of the drive shaft DS. The HVECU70 determines whether or not to load-operate the engine 10 based on the required torque Tr, the required running power Pd, the target charge/discharge power Pb of the power storage device 40 set separately, the allowable discharge power Wout, and the like.

When the engine 10 is to be load-operated, the HVECU70 sets a required power Pe (═ Pd × Pb + Loss) for the engine 10 based on the required traveling power Pd, the target charge/discharge power Pb, and the like. Then, the HVECU70 sets the target rotation speed Ne of the engine 10 corresponding to the required power Pe so that the engine 10 is efficiently operated and not lower than the lower limit rotation speed Nelim corresponding to the operation state of the hybrid vehicle 1 and the like. Then, HVECU70 sets torque commands Tm1 and Tm2 for motor generators MG1 and MG2 in accordance with required torque Tr and target rotation speed Ne, within the range of allowable charge power Win and allowable discharge power Wout of power storage device 40. On the other hand, when stopping the operation of the engine 10, the HVECU70 sets zero to the required power Pe, the target rotation speed Ne, and the torque command Tm 1. Then, HVECU70 sets torque command Tm2 within the range of allowable charge power Win and allowable discharge power Wout of power storage device 40 so that torque corresponding to required torque Tr is output from motor generator MG2 to drive shaft DS.

Then, the HVECU70 transmits the required power Pe and the target rotation speed Ne to the engine ECU100, and transmits the torque commands Tm1, Tm2 to the MGECU 55. The engine ECU100 executes intake air amount control, fuel injection control, ignition timing control, and the like based on the required power Pe and the target rotation speed Ne. In the present embodiment, the engine ECU100 basically executes the fuel injection control so that the air-fuel ratio in each cylinder 11 of the engine 10 becomes the stoichiometric air-fuel ratio (═ 14.6 to 14.7). When the load (required power Pe) of engine 10 is equal to or less than a predetermined value, fuel is injected from port injection valves 15p, and fuel injection from in-cylinder injection valves 15d is stopped. While the load on engine 10 exceeds the predetermined value, fuel injection from port injection valves 15p is stopped, and fuel is injected from in-cylinder injection valves 15 d. In the present embodiment, fuel injection and ignition to the plurality of cylinders 11 are performed in the order of cylinder #1 → cylinder #3 → cylinder #4 → cylinder #2 (ignition order).

The MGECU55 performs switching control of the 1 st and 2 nd inverters 51 and 52 and the boost converter 53 based on the torque commands Tm1 and Tm 2. When engine 10 is in load operation, motor generators MG1 and MG2 are controlled to convert part (at the time of charging power storage device 40) or all (at the time of discharging power storage device 40) of the electric power output from engine 10 into torque together with planetary gear 30 and output the converted torque to drive shaft DS. Thus, hybrid vehicle 1 travels using the power from engine 10 (direct transmission torque) and the power from motor generator MG2 (HV travel). In contrast, when the operation of engine 10 is stopped, hybrid vehicle 1 travels (EV travel) using only the power (drive torque) from motor generator MG 2.

Here, as described above, the hybrid vehicle 1 of the embodiment includes the downstream side purification device 19 having the particulate trap 190 as the exhaust gas purification device. The accumulation amount Dpm of particulate matter in the particulate trap 190 increases according to an increase in the travel distance of the hybrid vehicle 1, and increases as the ambient temperature is lower. Therefore, in the hybrid vehicle 1, at the stage when the amount Dpm of particulate matter accumulated in the particulate trap 190 increases, it is necessary to introduce a large amount of air, i.e., oxygen, into the particulate trap 190 having a sufficiently increased temperature and burn the particulate matter to regenerate the particulate trap 190. Thus, in the hybrid vehicle 1, the particulate trap regeneration necessity determining routine illustrated in fig. 3 is executed by the engine ECU100 every predetermined time when the engine 10 is in a load operation in accordance with the depression of the accelerator pedal 84 by the driver of the hybrid vehicle 1.

At the start of the routine of fig. 3, engine ECU100 acquires information necessary for determination, such as the intake air amount GA of engine 10, the rotation speed Ne, the cooling water temperature Tw, and the temperature Tpf of particulate trap 190 (step S100). Engine ECU100 calculates a deposition amount Dpm of particulate matter in particulate trap 190 by either an operation history method or a differential pressure method according to the operating state of engine 10 based on the physical amount obtained in step S100 or the like (step S110). Next, the engine ECU100 determines whether or not a catalyst temperature increase control routine for increasing the temperature of the exhaust purification catalyst 180 of the upstream side purification device 18 and the temperature of the particulate trap 190 of the downstream side purification device 19 is already being executed (step S120).

If it is determined in step S120 that the catalyst temperature increase control routine has not been executed (yes in step S120), engine ECU100 determines whether or not the deposition amount Dpm calculated in step S110 is equal to or greater than a predetermined threshold value D1 (for example, a value of approximately 5000 mg) (step S130). If it is determined in step S130 that the deposition amount Dpm is smaller than the threshold value D1 (no in step S130), the engine ECU100 once ends the routine of fig. 3 at this point in time. If it is determined in step S130 that the deposition amount Dpm is equal to or greater than the threshold value D1 (yes in step S130), engine ECU100 determines whether or not the temperature Tpf of particulate trap 190 acquired in step S100 is lower than a predetermined temperature increase control start temperature (predetermined temperature) Tx (step S140). Temperature increase control start temperature Tx is predetermined in accordance with the usage environment of hybrid vehicle 1, and in the present embodiment, is a temperature around 600 ℃.

If it is determined in step S140 that temperature Tpf of particulate trap 190 is equal to or higher than temperature increase control start temperature Tx (no in step S140), engine ECU100 once ends the routine of fig. 3 at that point in time. If it is determined in step S140 that the temperature Tpf of the particulate trap 190 is lower than the temperature-increase control start temperature Tx (yes in step S140), the engine ECU100 transmits a catalyst temperature-increase request signal requesting execution of the catalyst temperature-increase control routine to the HVECU70 (step S150), and once ends the routine of fig. 3. When the HVECU70 permits execution of the catalyst temperature increase control routine after transmission of the catalyst temperature increase request signal, the engine ECU100 sets the catalyst temperature increase flag to active (ON) and starts the catalyst temperature increase control routine.

On the other hand, if it is determined in step S120 that the catalyst temperature increase control routine has been executed (step S120: no), engine ECU100 determines whether or not the deposition amount Dpm calculated in step S110 is equal to or less than a threshold value D0 (for example, a value of about 3000 mg) that is set smaller in advance than the threshold value D1 (step S160). If it is determined in step S160 that the deposition amount Dpm exceeds the threshold value D0 (no in step S160), the engine ECU100 once ends the routine of fig. 3 at this point in time. If it is determined in step S160 that the deposition amount Dpm is equal to or less than the threshold value D0 (yes in step S160), the engine ECU100 deactivates (OFF) the catalyst temperature increase flag, ends the catalyst temperature increase control routine (step S170), and ends the routine of fig. 3.

Next, a catalyst temperature increase control routine for increasing the temperature of the exhaust purification catalyst 180 and the particulate trap 190 will be described. Fig. 4 is a flowchart illustrating a catalyst temperature increase control routine executed by engine ECU100 every predetermined time. The routine of fig. 4 is executed on condition that execution thereof is permitted by the HVECU70 during a period in which the engine 10 is under load operation in accordance with depression of the accelerator pedal 84 by the driver until the catalyst temperature increase flag is set to inactive in step S170 of fig. 3.

At the start of the routine of fig. 4, the engine ECU100 acquires information necessary for control such as the intake air amount GA of the engine 10, the rotation speed Ne, the cooling water temperature Tw, the temperature Tpf of the particulate trap 190, the crank position from the crank angle sensor 90, the requested power Pe from the HVECU70, and the target rotation speed Ne (step S200). After the process of step S200, engine ECU100 determines whether or not rich flag Fr is a value of 0 (step S210). Before the routine of fig. 4 is started, if the rich flag Fr is set to a value of 0 and it is determined in step S210 that the rich flag Fr is 0 (no in step S210), the engine ECU100 sets the rich flag Fr to a value of 1 (step S220).

Next, engine ECU100 sets a fuel injection control amount such as a fuel injection amount and a fuel injection end timing from each port injection valve 15p or each in-cylinder injection valve 15d (step S230). In step S230, the engine ECU100 sets the fuel injection amount to a predetermined 1 cylinder 11 (for example, the No. 1 cylinder #1) among the plurality of cylinders 11 of the engine 10 to zero. In step S230, the engine ECU100 increases the fuel injection amount to the remaining cylinders 11 (for example, the No. 2 cylinder #2, the No. 3 cylinder #3, and the No. 4 cylinder #4) other than the 1 cylinder 11 by, for example, 20% to 25% (20% in the present embodiment) of the fuel injection amount that should be originally supplied to the 1 cylinder 11 (the No. 1 cylinder # 1).

After setting the fuel injection control amount in step S230, engine ECU100 determines the cylinder 11 for which the fuel injection start timing has come, based on the crank position from crank angle sensor 90 (step S240). When it is determined by the determination process at step S240 that the fuel injection start timing for the above-described 1 cylinder 11 (cylinder #1) has come (no at step S250), engine ECU100 determines whether or not the fuel injection for 1 cycle of 2 revolutions of engine 10 is completed without injecting the fuel from port injection valve 15p or in-cylinder injection valve 15d corresponding to the above-described 1 cylinder 11 (step S270). While the fuel supply to the 1 cylinder 11 (No. 1 cylinder #1) is stopped (during fuel cut), the intake valve and the exhaust valve of the cylinder 11 are opened and closed in the same manner as in the case of fuel supply. When it is determined by the determination process at step S240 that the fuel injection start timing of any of the remaining cylinders 11 (cylinder #2, cylinder #3, or cylinder #4) has come (yes at step S250), engine ECU100 injects fuel into the cylinder 11 from the corresponding port injection valve 15p or in-cylinder injection valve 15d (step S260), and determines whether or not the fuel injection in 1 cycle is completed (step S270).

If it is determined in step S270 that fuel injection in cycle 1 is not completed (no in step S270), engine ECU100 repeatedly executes the processes in steps S240 to S260. While the routine is being executed, the opening degree of the throttle valve 14 is set based on the required power Pe and the target rotation speed Ne (required torque). Therefore, through the processing of steps S240 to S270, the supply of fuel to the above-described 1 cylinder 11 (No. 1 cylinder #1) is stopped, and the air-fuel ratios in the above-described remaining cylinders 11 (No. 2 cylinder #2, No. 3 cylinder #3, and No. 4 cylinder #4) are enriched. Hereinafter, the cylinder 11 to which the supply of fuel is stopped is appropriately referred to as a "fuel cut cylinder", and the cylinder 11 to which fuel is supplied is appropriately referred to as a "combustion cylinder". If engine ECU100 determines in step S270 that fuel injection in cycle 1 has been completed (yes in step S270), it executes the processing from step S200 onward again.

After setting the rich flag Fr to a value of 1 in step S220, the engine ECU100 determines that the rich flag Fr is a value of 1 in step S210 (yes in step S210). In this case, engine ECU100 determines whether temperature Tpf of particulate trap 190 acquired in step S200 is lower than a predetermined regeneration temperature (1 st determination threshold) Ty (step S215). The regeneration temperature Ty is a lower limit value of a temperature at which the regeneration of the particulate trap 190, that is, the combustion of the particulate matter, can be performed, or a temperature slightly higher than the lower limit value. The regeneration temperature Ty is predetermined in accordance with the usage environment of the hybrid vehicle 1, and is set to a temperature around 650 ℃. If it is determined in step S215 that temperature Tpf of particulate trap 190 is lower than regeneration temperature Ty (yes in step S215), engine ECU100 executes the processes of steps S230 to S270 described above, and executes the processes of step S200 and subsequent steps again.

If it is determined in step S215 that temperature Tpf of particulate trap 190 is equal to or higher than regeneration temperature Ty (no in step S215), engine ECU100 determines whether or not high temperature flag Ft is 0 as shown in fig. 5 (step S280). Before the routine of fig. 4 is started, the high temperature flag Ft is set to a value of 0, and if it is determined in step S280 that the high temperature flag Ft is 0 (yes in step S280), the engine ECU100 sets the rich flag Fr to a value of 0 (step S290). After setting rich flag Fr to a value of 0, engine ECU100 determines whether or not temperature Tpf of particulate trap 190 acquired in step S200 is equal to or higher than predetermined regeneration promoting temperature (2 nd determination threshold) Tz (step S300). The regeneration promoting temperature Tz is a temperature at which regeneration of the particulate trap 190, i.e., combustion of the particulate matter, can be promoted. The regeneration promoting temperature Tz is predetermined in accordance with the usage environment of the hybrid vehicle 1, and is set to a temperature around 700 ℃.

If it is determined in step S300 that temperature Tpf of particulate trap 190 is lower than regeneration promoting temperature Tz (no in step S300), engine ECU100 sets a fuel injection control amount such as a fuel injection amount and a fuel injection end timing from each port injection valve 15p or each in-cylinder injection valve 15d (step S310). In step S310, the engine ECU100 sets the fuel injection amount to the fuel cut cylinder (cylinder #1) among the plurality of cylinders 11 to zero. In step S310, engine ECU100 increases the fuel injection amount to all combustion cylinders (No. 2 cylinder #2, No. 3 cylinder #3, and No. 4 cylinder #4) other than the fuel-cut cylinder (No. 1 cylinder #1), by, for example, 3% to 7% (5% in the present embodiment) of the fuel injection amount that should be originally supplied to the fuel-cut cylinder.

After the fuel injection control amount is set in step S310, engine ECU100 repeatedly executes the processes of steps S240 to S260 until it is determined in step S270 that the fuel injection of 1 cycle is completed. Thus, the fuel supply to the 1 cylinder (fuel-cut cylinder) 11 (No. 1 cylinder #1) is stopped, and the air-fuel ratio in the remaining cylinders (combustion cylinders) 11 (No. 2 cylinder #2, No. 3 cylinder #3, and No. 4 cylinder #4) is changed to the lean side and is weakly rich as compared with the case where the process of step S230 is executed.

If it is determined in step S300 that the temperature Tpf of the particulate trap 190 is equal to or higher than the regeneration promoting temperature Tz (yes in step S300), the engine ECU100 sets the high temperature flag Ft to a value of 1 (step S305). Then, in step S305, the engine ECU100 transmits an additional F/C cylinder addition request signal for requesting addition of a fuel cut cylinder to the HVECU 70. Then, engine ECU100 sets the fuel injection control amount for each port injection valve 15p or each in-cylinder injection valve 15d (step S310), and repeatedly executes the processing of steps S240 to S260 until it is determined in step S270 that the fuel injection of cycle 1 is completed.

In the present embodiment, after setting the high temperature flag Ft to a value of 1 in step S305, the engine ECU100 transmits the F/C cylinder addition request signal to the HVECU70 1 time per 2 cycles (4 revolutions of the engine 10). The permission or non-permission of the addition of this fuel cut cylinder is determined by the HVECU 70. When the HVECU70 permits addition of a fuel-cut cylinder, the engine ECU100 selects (adds) the cylinder 11 (in the present embodiment, the No. 4 cylinder #4) in which fuel injection (ignition) is not continuously performed with respect to the No. 1 cylinder #1 in the non-execution of the catalyst temperature increase control routine as a new fuel-cut cylinder.

When the HVECU70 permits addition of the fuel-cut cylinder, the engine ECU100 sets the fuel injection amount to the fuel-cut cylinder (the No. 1 cylinder #1 and the No. 4 cylinder #4) among the plurality of cylinders 11 to zero in step S310. In step S310, engine ECU100 increases the fuel injection amount to all combustion cylinders (cylinder #2 and cylinder #3) other than the fuel-cut cylinder by, for example, 3% to 7% (5% in the present embodiment) of the fuel injection amount that should be supplied to 1 fuel-cut cylinder. In this case, after the process of step S310, engine ECU100 executes the processes of steps S240 to S270, and executes the processes of step S200 and thereafter again. Thus, the fuel supply to the 2 cylinders 11 (the No. 1 cylinder #1 and the No. 4 cylinder #4) is stopped, and the air-fuel ratios in the remaining cylinders 11 (the No. 2 cylinder #2 and the No. 3 cylinder #3) are changed to the lean side and are weakly rich as compared with the case where the process of step S230 is executed.

After setting the high temperature flag Ft to a value of 1 in step S305, the engine ECU100 determines that the high temperature flag Ft is a value of 1 in step S280 (no in step S280). In this case, engine ECU100 determines whether or not temperature Tpf of particulate trap 190 acquired in step S200 is lower than temperature increase control start temperature Tx described above (step S320). If it is determined in step S320 that temperature Tpf of particulate filter 190 is equal to or higher than temperature increase control start temperature Tx (no in step S320), engine ECU100 executes the processes of steps S310, S240 to S270, and executes the processes of step S200 and subsequent steps again. On the other hand, if it is determined in step S320 that the temperature Tpf of the particulate trap 190 is lower than the temperature-raising control start temperature Tx (yes in step S320), the engine ECU100 sets the high-temperature flag Ft to a value of 0 (step S325). Then, in step S325, the engine ECU100 sends an F/C cylinder reduction signal to the HVECU70 in order to notify the restart of fuel supply to the previously added fuel-cut cylinder (cylinder # 4).

After the process of step S325, engine ECU100 sets the rich flag Fr to the value 1 again in step S220 of fig. 4. Then, the engine ECU100 sets the fuel injection amount to the fuel-cut cylinder (cylinder #1) in which the fuel supply is continuously stopped to zero, and increases the fuel injection amount to the remaining cylinders (combustion cylinders) 11 (cylinder #2, cylinder #3, and cylinder #4) by 20% of the fuel injection amount that should be originally supplied to the 1 fuel-cut cylinder (cylinder #1) (step S230). Thus, by the processing in steps S240 to S270, the fuel supply to the 1 cylinder (fuel-cut cylinder) 11 (No. 1 cylinder #1) is stopped, and the air-fuel ratios in the remaining cylinders (combustion cylinders) 11 (No. 2 cylinder #2, No. 3 cylinder #3, and No. 4 cylinder #4) are enriched again.

Fig. 6A and 6B are flowcharts illustrating a drive control routine that is repeatedly executed by the HVECU70 at predetermined intervals in parallel with the above-described catalyst temperature increase control routine after the engine ECU100 transmits the catalyst temperature increase request signal in step S150 in fig. 3.

At the start of the routine of fig. 6A and 6B, HVECU70 acquires information necessary for control, such as accelerator opening Acc, vehicle speed V, the crank position from crank angle sensor 90, rotation speeds Nm1, Nm2 of motor generators MG1, MG2, SOC of power storage device 40, target charge/discharge power Pb, allowable charge power Win and allowable discharge power Wout, an F/C cylinder addition request signal from engine ECU100, presence/absence of reception of an F/C cylinder reduction signal, and the value of a rich flag Fr from engine ECU100 (step S400). Next, HVECU70 sets required torque Tr based on accelerator opening Acc and vehicle speed V, and sets required power Pe for engine 10 based on required torque Tr (required traveling power Pd), target charge/discharge power Pb of power storage device 40, and the like (step S410).

Further, the HVECU70 determines whether or not the engine ECU100 has started the catalyst temperature increase control routine of fig. 4 and 5 (step S420). If it is determined in step S420 that the engine ECU100 has not started the catalyst temperature increase control routine (yes in step S420), the HVECU70 sets a predetermined value Neref to a lower limit rotation speed Nelim that is the lower limit value of the rotation speed of the engine 10 (step S430). The value Neref is a value that is larger than the lower limit value of the rotation speed of the engine 10 when the catalyst temperature increasing control routine is not executed, for example, about 400-. The process of step S430 is skipped after the catalyst temperature increasing control routine is started by engine ECU 100.

After the processing in step S420 or S430, the HVECU70 derives the rotation speed for operating the engine 10 efficiently in accordance with the required power Pe from a map, not shown, and sets the greater one of the derived rotation speed and the lower limit rotation speed Nelim as the target rotation speed Ne of the engine 10 (step S440). In step S440, the HVECU70 sets the required power Pe divided by the target rotation speed Ne as the target torque Te of the engine 10. Then, HVECU70 sets a torque command Tm1 for motor generator MG1 corresponding to target torque Te and target rotation speed Ne and a torque command Tm2 for motor generator MG2 corresponding to required torque Tr and torque command Tm1 within the range of allowable charging power Win and allowable discharging power Wout of power storage device 40 (step S450).

Next, the HVECU70 determines whether or not execution of the catalyst temperature increase control routine described above, that is, whether or not to permit the stop of fuel supply to some of the cylinders 11 (hereinafter, "stop of fuel supply" is appropriately referred to as "fuel cut (F/C)") is permitted in accordance with a request from the engine ECU100 (step S460). In step S460, the HVECU70 calculates a drive torque that is insufficient due to fuel cut of 1 cylinder 11, that is, a torque that is no longer output from the engine 10 due to fuel cut (hereinafter, appropriately referred to as "insufficient torque"). More specifically, HVECU70 calculates the insufficient torque (Tr · G/n) by multiplying a value obtained by dividing the required torque Tr set in step S410 by the number n of cylinders of engine 10 (in the present embodiment, n is 4) by the gear ratio G between the rotor of motor generator MG2 and drive shaft DS. In step S460, HVECU70 determines whether or not the insufficient torque can be compensated for by motor generator MG2, based on the insufficient torque, torque commands Tm1 and Tm2 set in step S450, and allowable charge power Win and allowable discharge power Wout of power storage device 40. At this time, when the F/C cylinder addition request signal or the F/C cylinder reduction signal is received from the engine ECU100, the HVECU70 determines whether or not compensation of the insufficient torque is possible in consideration of the increase or decrease of the fuel cut cylinder.

If it is determined as a result of the determination processing at step S460 that insufficient drive torque due to fuel cut of a part (1 or 2) of cylinders 11 can be compensated for from motor generator MG2 (yes at step S470), HVECU70 transmits a fuel cut permission signal to engine ECU100 (step S480). The fuel-cut permission signal also includes a fuel-cut permission signal that permits fuel-cutting only for 1 cylinder 11 when the F/C cylinder addition request signal is sent from the engine ECU 100. When it is determined as a result of the determination processing at step S460 that the insufficient drive torque due to fuel cut of some of the cylinders 11 cannot be compensated for from the motor generator MG2 (no at step S470), the HVECU70 transmits a fuel cut prohibition signal to the engine ECU100 (step S485), and once ends the routine of fig. 6A and 6B. In this case, execution of the catalyst temperature increase control routine of engine ECU100 is suspended or stopped.

When the fuel cut permission signal is transmitted to the engine ECU100 in step S480, the HVECU70 transmits the required power Pe set in step S410 and the target rotation speed Ne set in step S440 to the engine ECU100 (step S490). Then, the HVECU70 determines the cylinder 11 in which the fuel injection start timing comes next based on the crank position from the crank angle sensor 90 (step S500). When the HVECU70 determines that the fuel injection start timing of the fuel cut cylinder (cylinder #1 or cylinder #1 and cylinder #4) has come through the determination processing in step S500 (no in step S510), it resets the torque command Tm2 to the motor generator MG2 (step S515).

In step S515, the HVECU70 sets the sum of the torque command Tm2 set in step S450 and the insufficient torque (Tr × G/n) as a new torque command Tm 2. After the process of step S515, the HVECU70 transmits the torque command Tm1 set in step S450 and the torque command Tm2 set again in step S515 to the MGECU55 (step S560), and once ends the routine of fig. 6A and 6B. Thus, while the fuel supply to any one of the cylinders 11 of the engine 10 is stopped (during fuel cut), the motor generator MG1 is controlled by the MGECU55 so as to rotate the engine 10 at the target rotation speed Ne, and the motor generator MG2 is controlled by the MGECU55 so as to compensate for the insufficient torque.

On the other hand, when it is determined that the fuel injection start timing of the combustion cylinder (cylinder #2 to cylinder #4 No. 2 or cylinder #2 and cylinder #3) has come through the determination processing in step S500 (yes in step S510), the HVECU70 determines whether or not the rich flag Fr acquired in step S400 is at the value 1 (step S520). If it is determined in step S520 that the rich flag Fr is set to the value 1 (yes in step S520), the HVECU70 calculates the residual torque Tex (positive value) of the engine 10 due to the enrichment of the air-fuel ratio in 1 combustion cylinder from the accelerator opening Acc or the target torque Te and the increase rate of fuel in 1 combustion cylinder (20% in the present embodiment) used in step S230 of fig. 4 (step S530).

Then, HVECU70 determines whether or not power storage device 40 can be charged with the electric power generated by motor generator MG1 when residual torque Tex is cancelled by rotating engine 10 at target rotation speed Ne by motor generator MG1, based on residual torque Tex, target rotation speed Ne and target torque Te set in step S440, torque command Tm1 set in step S450, allowable charging power Win of power storage device 40, and the like (step S540). If it is determined in step S540 that residual torque Tex can be cancelled by motor generator MG1 (yes in step S540), HVECU70 sets torque commands Tm1 and Tm2 again in consideration of residual torque Tex (step S550).

In step S550, HVECU70 adds the value (negative value) of the component of residual torque Tex that acts on motor generator MG1 via planetary gear 30 to torque command Tm1 set in step S450, and sets a new torque command Tm 1. In step S550, the HVECU70 subtracts the value (positive value) of the component of the residual torque Tex, which is transmitted to the drive shaft DS via the planetary gear 30, from the torque command Tm2 to set a new torque command Tm 2. After the process of step S550, the HVECU70 transmits the torque commands Tm1 and Tm2 set again to the MGECU55 (step S560), and once ends the routine of fig. 6A and 6B. Thus, when the residual torque Tex can be cancelled by the motor generator MG1, while fuel is supplied so that the air-fuel ratio becomes rich in all the combustion cylinders except the fuel cut cylinder in steps S230 to S270 in fig. 4, the motor generator MG1 is controlled by the MGECU55 so that the engine 10 is rotated at the target rotation speed Ne and the residual power of the engine 10 based on the residual torque Tex is converted into electric power. During this period, the MGECU55 controls the motor generator MG2 so as to output a torque corresponding to the torque command Tm2 set in step S450 without compensating for the insufficient torque.

On the other hand, if it is determined in step S540 that residual torque Tex cannot be cancelled by motor generator MG1 (yes in step S540), HVECU70 transmits an ignition retard request signal that requests retardation of the ignition timing to engine ECU100 (step S555). Then, the HVECU70 transmits the torque commands Tm1 and Tm2 set in step S450 to the MGECU55 (step S560), and once ends the routine of fig. 6A and 6B. Thus, when residual torque Tex cannot be cancelled by motor generator MG1, motor generator MG1 is controlled by MGECU55 to rotate engine 10 at target rotation speed Ne while fuel is supplied so that the air-fuel ratio is rich in all combustion cylinders except the fuel cut cylinder in steps S230 to S270 in fig. 4. During this period, the MGECU55 controls the motor generator MG2 so as to output a torque corresponding to the torque command Tm2 set in step S450 without compensating for the insufficient torque. Then, upon receiving the ignition delay request signal from the HVECU70, the engine ECU100 retards the ignition timing in each combustion cylinder from the optimum ignition timing (MBT) as shown in fig. 7 so that the output torque of the engine 10 is equivalent to the case where the air-fuel ratio in the combustion cylinder is set to the stoichiometric air-fuel ratio.

If it is determined in step S520 that the rich flag Fr is 0 (no in step S520), the HVECU70 transmits the torque commands Tm1 and Tm2 set in step S450 to the MGECU55 (step S550), and once ends the routine of fig. 6A and 6B. Thus, while the rich flag Fr is set to a value of 0 and fuel is supplied so that the air-fuel ratio becomes a lean value (weakly rich) in all the combustion cylinders except the fuel cut cylinder in steps S310, S240 to S270 in fig. 4, the motor generator MG1 is controlled by the MGECU55 so that the engine 10 rotates at the target rotation speed Ne. During this period, the MGECU55 controls the motor generator MG2 so as to output a torque corresponding to the torque command Tm2 set in step S450 without compensating for the insufficient torque.

As a result of executing the routine shown in fig. 3 to 6B, in the hybrid vehicle 1, when the accumulation amount Dpm of particulate matter in the particulate trap 190 of the downstream-side purification device 19 becomes equal to or greater than the threshold value D1, a catalyst temperature increase request signal is transmitted from the engine ECU100 to the HVECU70 in order to increase the temperature of the exhaust gas purification catalyst 180 of the upstream-side purification device 18 and the particulate trap 190 of the downstream-side purification device 19 (step S150 in fig. 3). When the HVECU70 permits the temperature increase of the particulate trap 190 and the like, the engine ECU100 executes a catalyst temperature increase control routine (fig. 4 and 5) that stops the supply of fuel to at least one of the cylinders 11 of the engine 10 and supplies fuel to the remaining cylinders 11 while the engine 10 is in load operation in response to the depression of the accelerator pedal 84 by the driver. During execution of the catalyst temperature increase control routine, HVECU70 controls motor generator MG2 (fig. 6A and 6B) as a power generation device so as to compensate for the torque (driving force) that is insufficient due to the stop of fuel supply to at least one of cylinders 11.

Thus, the torque insufficient due to the stop of the fuel supply to some of the cylinders 11 can be compensated with high accuracy and high responsiveness from the motor generator MG2, and the torque corresponding to the required torque Tr can be output to the wheels W during the execution of the catalyst temperature increasing control routine. While the fuel supply to at least one of the cylinders 11 is stopped (during fuel cut), the HVECU70 (and MGECU55) controls the motor generator MG2 (electric motor) so as to compensate for the insufficient torque (steps S515 and S560 in fig. 6B). As a result, deterioration of drivability of the hybrid vehicle 1 can be suppressed very well during execution of the catalyst temperature increase control routine.

Further, the HVECU70 increases the lower limit rotation speed Nelim of the engine 10 during execution of the catalyst temperature increase control routine as compared with the case where the catalyst temperature increase control routine is not executed (step S430 in fig. 6A). This can shorten the time during which the fuel supply to some of the cylinders 11 is stopped, that is, the time during which the engine 10 no longer outputs torque due to the fuel cut. Therefore, in the hybrid vehicle 1, the surface formation (appearance) of the vibration of the engine 10 due to the fuel cut of some of the cylinders 11 can be extremely well suppressed.

When the engine ECU100 is permitted to execute the catalyst temperature increase control routine by the HVECU70 (time t1 in fig. 8), the engine ECU100 stops the fuel supply to any one of the cylinders 11 (cylinder #1) of the engine 10 and makes the air-fuel ratio in the remaining cylinders 11 (cylinder #2, cylinder #3, and cylinder #4) rich (steps S230 to S270 in fig. 4). Thus, relatively much air, i.e., oxygen, is introduced from the cylinder 11 (fuel cut cylinder) to which the fuel supply is stopped to the upstream and downstream side purification devices 18, 19, and relatively much unburned fuel is introduced from the cylinder 11 (combustion cylinder) to which the fuel is supplied to the upstream and downstream side purification devices 18, 19. That is, air (air containing almost no fuel component, not lean atmosphere) is supplied from the fuel cut cylinder to the upstream and downstream purge devices 18 and 19 in an amount substantially equal to the capacity (volume) of the cylinder 11. As a result, during the load operation of the engine 10, relatively large amounts of unburned fuel can be reacted in the presence of sufficient oxygen, and as shown in fig. 8, the temperatures of the exhaust purification catalyst 180 and the particulate trap 190 carrying the exhaust purification catalyst can be sufficiently and quickly raised by the reaction heat.

While fuel is supplied to all the combustion cylinders other than the fuel-cut cylinder so that the air-fuel ratio becomes rich in this way, HVECU70 (and MGECU55) controls motor generator MG 1(2 nd electric motor) so as to convert the surplus power of engine 10 generated by the enrichment of the air-fuel ratio in the remaining cylinder 11 (combustion cylinder) into electric power (steps S510-S560 in fig. 6B). This makes it possible to suppress deterioration of the fuel economy of engine 10 associated with execution of the catalyst temperature increase control routine without complicating control of motor generator MG2 for compensating for the insufficient torque.

Then, when the charge of power storage device 40 is restricted and the surplus power of engine 10 cannot be converted into electric power by motor generator MG1, HVECU70 transmits an ignition retard request signal that requests retardation of the ignition timing to engine ECU100 (step S555 in fig. 6B). Then, engine ECU100, which receives the ignition retard request signal, retards the ignition timing in the combustion cylinder from the optimal ignition timing (MBT). Accordingly, even when the charging of power storage device 40 by the electric power generated by motor generator MG1 is restricted, the drivability of hybrid vehicle 1 can be ensured satisfactorily while suppressing an increase in the output torque of engine 10 associated with the enrichment of the air-fuel ratio in the combustion cylinder.

Further, when the temperature Tpf of the particulate trap 190 becomes equal to or higher than the regeneration temperature Ty (the 1 st determination threshold value) during execution of the catalyst temperature increasing control (time t2 in fig. 8), the engine ECU100 stops the fuel supply to the 1 cylinder 11 (the No. 1 cylinder #1) and changes the air-fuel ratio in the entire remaining cylinders 11 (combustion cylinders) to the lean side to make the air-fuel ratio weakly rich (step S310 in fig. 5, etc.). Then, when the temperature Tpf of the particulate trap 190 becomes equal to or higher than the regeneration promoting temperature Tz (the 2 nd determination threshold) higher than the regeneration promoting temperature Ty during execution of the catalyst temperature increase control (time t3 in fig. 8), the engine ECU100 stops the supply of fuel to any one of the remaining cylinders 11 (the No. 4 cylinder #4) under the condition that the torque insufficient due to the execution of the catalyst temperature increase control routine can be compensated by the motor generator MG2 (steps S460 to S480 in fig. 6A) (step S305 in fig. 5, etc.).

This makes it possible to stably operate the engine 10 in which the supply of fuel to some of the cylinders 11 is stopped, and to supply more oxygen from the plurality of fuel cut cylinders into the upstream and downstream purification devices 18 and 19 having a sufficiently increased temperature. Therefore, in the hybrid vehicle 1, more oxygen can be introduced from the plurality of fuel cut cylinders into the particulate trap 190 whose temperature has been raised together with the exhaust purification catalyst, and the particulate matter deposited on the particulate trap 190 can be favorably burned. In addition, in the hybrid vehicle 1, the S poisoning and the HC poisoning of the exhaust purification catalyst 180 of the upstream side purification device 18 can be favorably alleviated.

When the HVECU70 permits addition of a fuel-cut cylinder, the engine ECU100 selects the cylinder 11 (cylinder #4) in which fuel injection (ignition) is not continuously performed with respect to the 1 cylinder 11 (cylinder #1) described above when the catalyst temperature increase control routine is not executed, as a new fuel-cut cylinder. That is, when stopping the fuel supply to the 2 (a plurality of) cylinders 11, the engine ECU100 executes the catalyst temperature increase control routine so as to stop the fuel supply to any one of the cylinders 11 and supply fuel to at least 1 of the cylinders 11. Accordingly, since the fuel supply to the plurality of cylinders 11 is not continuously stopped, the variation in torque output from the engine 10 and the deterioration of engine noise can be suppressed.

When the temperature Tpf of the post-fuel-cut-cylinder particulate trap 190 becomes lower than the temperature-raising-control start temperature Tx (time t4 in fig. 8), the engine ECU100 decreases the number of fuel-cut cylinders and makes the air-fuel ratio in the cylinder 11 (combustion cylinder) to which fuel is supplied rich (step S325 in fig. 5, and steps S220 to S270 in fig. 4), as shown in fig. 8. Thus, when the temperatures of the upstream and downstream purification devices 18 and 19 decrease due to an increase in the amount of air introduced into the upstream and downstream purification devices 18 and 19 associated with the addition of the fuel cut cylinder, the air-fuel ratio in the combustion cylinder can be made rich to increase the temperatures of the upstream and downstream purification devices 18 and 19 again, and the amount of air introduced into the upstream and downstream purification devices 18 and 19 can be reduced by the decrease in the amount of fuel cut cylinder to suppress a decrease in the temperatures of the upstream and downstream purification devices.

When the accumulation amount Dpm in the particulate trap 190 becomes equal to or less than the threshold value D0 (time t5 in fig. 8), the engine ECU100 deactivates the catalyst temperature increase flag and ends the catalyst temperature increase control routine. However, when the continuation time of the accelerator ON state is relatively short and the accumulation amount Dpm in the particulate trap 190 does not become equal to or less than the threshold value D0 during this time, the routine of fig. 4 to 6B is once interrupted and is restarted the next time the accelerator pedal 84 is depressed by the driver.

As described above, in the hybrid vehicle 1, while suppressing deterioration of drivability during load operation of the engine 10, the upstream and downstream purification devices 18 and 19 are sufficiently and quickly warmed up, and oxygen can be supplied to the upstream and downstream purification devices 18 and 19 in an amount sufficient for regeneration of the exhaust purification catalyst 180 and the particulate trap 190. That is, according to the above-described catalyst temperature increase control routine, even in a low temperature environment in which a large amount of particulate matter is likely to accumulate in the particulate trap 190 (particularly, in an extremely low temperature environment in which the average temperature of 1 day is lower than-20 ℃), the particulate matter accumulated in the particulate trap 190 can be favorably burned and the particulate trap 190 can be regenerated.

In the above-described embodiment, the air-fuel ratio is enriched in all the combustion cylinders other than the fuel cut cylinder if the execution of the catalyst temperature increase control routine is permitted, but the present invention is not limited thereto. That is, in the hybrid vehicle 1, instead of enriching the air-fuel ratio in the combustion cylinder at the beginning of the catalyst temperature increase control routine, the air-fuel ratio in the combustion cylinder may be set to the stoichiometric air-fuel ratio. In this embodiment, although it takes time to raise the temperature of the upstream and downstream purification devices 18 and 19 as compared with the case where the air-fuel ratio in the combustion cylinder is rich, the unburned fuel can be reacted in the presence of sufficient oxygen, and the temperature of the upstream and downstream purification devices 18 and 19 can be sufficiently raised by the heat of reaction. By continuing to stop the supply of fuel to some of the cylinders 11, a sufficient amount of oxygen can be supplied to the insides of the upstream and downstream purification devices 18 and 19 after the temperature has been raised.

In the above embodiment, the air-fuel ratio is changed to the lean side in all the combustion cylinders after the temperature Tpf of the particulate trap 190 becomes equal to or higher than the regeneration temperature Ty (the 1 st determination threshold value). That is, in the hybrid vehicle 1, the air-fuel ratio in the remaining cylinders 11 other than the fuel cut cylinder may be made rich until the temperature Tpf of the particulate trap 190 reaches the regeneration promoting temperature Tz (determination threshold). After the temperature Tpf becomes equal to or higher than the regeneration promoting temperature Tz, the fuel supply to any of the remaining cylinders 11 may be stopped and the air-fuel ratio in the cylinder 11 in which the fuel supply to the remaining cylinder 11 is not stopped may be changed to a lean side (weakly rich) on the condition that the above-described insufficient torque can be compensated for by the motor generator MG 2. According to this embodiment, after the exhaust purification catalyst 180 and the particulate trap 190 are sufficiently and rapidly heated, more oxygen can be supplied to the insides of the upstream and downstream purification devices 18 and 19.

In step S310 of fig. 5, the fuel injection amount may be set so that the air-fuel ratio in all the combustion cylinders other than the fuel cut cylinder becomes lean. After the temperature Tpf of the particulate trap 190 becomes equal to or higher than the regeneration promoting temperature Tz, the air-fuel ratio may be made lean in all the combustion cylinders other than the fuel cut cylinder as shown by the two-dot chain line in fig. 8, instead of adding the fuel cut cylinder. Further, when the air-fuel ratio in the combustion cylinder is changed during execution of the catalyst temperature increasing control routine, the air-fuel ratio in each combustion cylinder may be gradually changed in accordance with a change in the temperature Tpf of the particulate trap 190, for example, as shown by the broken line in fig. 8.

In hybrid vehicle 1, the surplus power of engine 10 generated by enriching the air-fuel ratio in the combustion cylinder may be converted into electric power by motor generator MG2 instead of motor generator MG 1. In this case, in step S540 of fig. 6B, it is determined whether or not the power storage device 40 can be charged with the electric power generated by the motor generator MG2 when the residual torque Tex is cancelled by the motor generator MG 2. In step S550 of fig. 6B, the torque command Tm2 is set again by subtracting the torque corresponding to the surplus torque Tex from the torque command Tm2 set in step S450. Then, in step S560, the torque command Tm1 set in step S450 and the torque command Tm2 set again in step S550 are transmitted to the MGECU 55. If it is determined in step S520 in fig. 6B that the rich flag Fr has the value 1, the ignition delay request signal may be uniformly transmitted to the engine ECU 100. Even in this manner, when the air-fuel ratio in each combustion cylinder is made rich during execution of the catalyst temperature increase control routine, it is possible to output torque corresponding to the required torque Tr to the wheels W and to ensure satisfactory drivability of the hybrid vehicle 1.

The engine 10 of the hybrid vehicle 1 is an in-line engine, and the catalyst temperature increasing control routine is configured to stop the supply of fuel to at least 1 cylinder 11 in 1 cycle, but is not limited thereto. That is, the engine 10 of the hybrid vehicle 1 may be a V-type engine, a horizontally opposed engine, or a W-type engine in which an exhaust gas purification device is provided for each bank. In this case, the catalyst temperature increasing control routine is preferably configured to stop the fuel supply to at least 1 cylinder in each bank in 1 cycle. This makes it possible to supply sufficient oxygen to the exhaust gas purification device of each bank of a V-type engine or the like.

The downstream-side purification device 19 may include an exhaust purification catalyst (three-way catalyst) disposed on the upstream side and a particulate trap disposed on the downstream side of the exhaust purification catalyst. In this case, the upstream side purge device 18 may be omitted from the hybrid vehicle 1. Further, the downstream-side purification device 19 may include only the particle trap. In this case, by raising the temperature of the exhaust purification catalyst of the upstream purification device 18 by executing the catalyst temperature raising control routine, the temperature of the downstream purification device 19 (particulate trap 190) can be raised by the high-temperature exhaust gas flowing from the upstream purification device 18.

In the hybrid vehicle 1, the motor generator MG1 may be coupled to the sun gear 31 of the planetary gear 30, the output member may be coupled to the ring gear 32, and the engine 10 and the motor generator MG2 may be coupled to the carrier 34. Further, a stepped transmission may be coupled to the ring gear 32 of the planetary gear 30. In the hybrid vehicle 1, the planetary gear 30 may be replaced with a 4-element compound planetary gear mechanism including 2 planetary gears. In this case, the engine 10 may be connected to the input element of the compound planetary gear mechanism, the output member may be connected to the output element, the motor generator MG1 may be connected to one of the remaining 2 rotational elements, and the motor generator MG2 may be connected to the other rotational element. The compound planetary gear mechanism may be provided with a clutch that couples any 2 of the 4 rotational elements and a brake that can restrict any one of the 4 rotational elements to be unrotatable. The hybrid vehicle 1 may be a plug-in hybrid vehicle capable of charging the power storage device 40 with electric power from an external power supply such as a household power supply or a rapid charger installed in a power station.

Fig. 9 is a schematic configuration diagram showing another hybrid vehicle 1B of the present disclosure. Among the components of the hybrid vehicle 1B, the same components as those of the hybrid vehicle 1 described above are denoted by the same reference numerals, and redundant description thereof is omitted.

A hybrid vehicle 1B shown in fig. 9 is a series-parallel hybrid vehicle including an engine (internal combustion engine) 10B having a plurality of cylinders (not shown), motor generators (synchronous generator motors) MG1, MG2, and a transaxle 20B. The engine 10B includes an upstream-side purification device 18 and a downstream-side purification device 19 as exhaust gas purification devices. A crankshaft (not shown) of engine 10B, a rotor of motor generator MG1, and wheel W1 are coupled to transaxle 20B. Motor generator MG2 is coupled to wheel W2 different from wheel W1. However, motor generator MG2 may be coupled to wheel W1. Transaxle 20B may also include a stepped transmission, a continuously variable transmission, a dual clutch transmission, or the like.

This hybrid vehicle 1B can travel with a drive torque (drive force) of at least one of motor generators MG1 and MG2 driven by electric power from power storage device 40 when the operation of engine 10B is stopped. In hybrid vehicle 1B, it is also possible to convert all of the power from engine 10B in the load operation into electric power by motor generator MG1 and drive motor generator MG2 with the electric power from motor generator MG 1. In the hybrid vehicle 1B, the drive torque (drive force) from the load-operated engine 10B can also be transmitted to the wheels W1 via the transaxle 20B.

In the hybrid vehicle 1B, while the drive torque from the engine 10B in the load operation is transmitted to the wheels W1 via the transaxle 20B, the engine ECU, not shown, executes the catalyst temperature increasing routine similar to the catalyst temperature increasing routine shown in fig. 4 and 5. While the catalyst temperature increasing routine is being executed, motor generator MG2 is controlled so as to compensate for insufficient drive torque due to fuel cut in some of the cylinders of engine 10B. As a result, the hybrid vehicle 1B can also obtain the same operational effects as the hybrid vehicle 1 described above. In the hybrid vehicle 1B, during execution of the catalyst temperature increase control routine, downshift (change of the gear ratio) of the transmission included in the transaxle 20B may be appropriately performed so that the rotation speed of the engine 10B becomes equal to or higher than the predetermined rotation speed. This can increase the rotation speed of engine 10B to shorten the time during which the supply of fuel to the partial cylinders is stopped, thereby suppressing the occurrence of surface deterioration of engine 10B such as vibration extremely well.

Fig. 10 is a schematic configuration diagram showing still another hybrid vehicle 1C of the present disclosure. Of the components of the hybrid vehicle 1C, the same components as those of the hybrid vehicle 1 described above are denoted by the same reference numerals, and redundant description thereof is omitted.

A hybrid vehicle 1C shown in fig. 10 is a series-parallel hybrid vehicle including an engine (internal combustion engine) 10C including a plurality of cylinders (not shown) and motor generators (synchronous generator motors) MG1, MG 2. In hybrid vehicle 1C, the crankshaft of engine 10C and the rotor of motor generator MG1 are coupled to shaft 1S 1, and motor generator MG1 can convert at least a part of the power from engine 10C into electric power. The rotor of the motor generator MG2 is coupled to the 2 nd shaft S2 directly or via a power transmission mechanism 120 including a gear train and the like, and the 2 nd shaft S2 is coupled to the wheels W via a differential gear 39 and the like. Motor generator MG2 may be coupled to a wheel, not shown, other than wheel W. Also, the hybrid vehicle 1C includes a clutch K that connects and disconnects the 1 st shaft S1 and the 2 nd shaft S2 to each other. In the hybrid vehicle 1C, the power transmission mechanism 120, the clutch K, and the differential gear 39 may be included in a transaxle.

In the hybrid vehicle 1C, when the clutch K is engaged, the drive torque from the engine 10C can be output to the 2 nd shaft S2, i.e., the wheel W. In the hybrid vehicle 1C, while the crankshaft of the engine 10C and the wheels W, which are the 2 nd shaft S2, are coupled by the clutch K and the engine 10C is in a load operation in response to depression of the accelerator pedal by the driver, the engine ECU, not shown, executes a catalyst temperature increasing routine similar to the catalyst temperature increasing routine shown in fig. 4 and 5. While the catalyst temperature increasing routine is being executed, motor generator MG2 is controlled so as to compensate for insufficient drive torque due to fuel cut in some of the cylinders of engine 10C. As a result, the same operational effects as those of the hybrid vehicle 1 and the like can be obtained in the hybrid vehicle 1C.

Fig. 11 is a schematic configuration diagram showing another hybrid vehicle 1D of the present disclosure. Of the components of the hybrid vehicle 1D, the same components as those of the hybrid vehicle 1 and the like described above are denoted by the same reference numerals, and redundant description thereof is omitted.

A hybrid vehicle 1D shown in fig. 11 is a parallel hybrid vehicle including an engine (internal combustion engine) 10D including a plurality of cylinders (not shown), a motor generator (synchronous generator motor) MG, a hydraulic clutch K0, a power transmission device 21, an electrical storage device (high-voltage battery) 40D, an auxiliary battery (low-voltage battery) 42, a PCU50D that drives the motor generator MG, a MGECU55D that controls the PCU50D, and a main electronic control unit (hereinafter, referred to as "main ECU") 170 that controls the engine 10D and the power transmission device 21. The engine 10D includes an upstream-side purification device 18 and a downstream-side purification device 19 as exhaust gas purification devices, and a crankshaft of the engine 10D is connected to an input member of a damper mechanism 24. Motor generator MG operates as an electric motor that is driven by electric power from power storage device 40D to generate drive torque, and outputs regenerative braking torque at the time of braking of hybrid vehicle 1D. Motor generator MG also operates as a generator for converting at least a part of the power from engine 10D in the load operation into electric power. As shown in the drawing, the rotor of motor generator MG is fixed to input shaft 21i of power transmission device 21.

Clutch K0 couples the crankshaft of engine 10D, which is the output member of damper mechanism 24, to the rotor of motor generator MG, which is input shaft 21i, and decouples the two. The power transmission device 21 includes a torque converter (fluid transmission device) 22, a multi-plate or one-plate lockup clutch 23, a mechanical oil pump MOP, an electric oil pump EOP, a transmission 25, a hydraulic control device 27 that adjusts the pressure of the hydraulic oil, and the like. The transmission 25 is, for example, a 4-to 10-speed transmission type automatic transmission, and includes a plurality of planetary gears, and a plurality of clutches and brakes (frictional engagement elements). The transmission 25 shifts the power transmitted from the input shaft 21i via either the torque converter 22 or the lock-up clutch 23 to multiple stages and outputs the power from the output shaft 21o of the power transmission device 21 to the drive shaft DS via the differential gear 39. However, the transmission 25 may be a mechanical continuously variable transmission, a dual clutch transmission, or the like. A clutch (see the two-dot chain line in fig. 11) for connecting and disconnecting the rotor of the motor generator MG and the input shaft 21i of the power transmission device 21 may be disposed therebetween.

In hybrid vehicle 1D, while the crankshaft of engine 10D and motor generator MG as input shaft 21i are coupled by clutch K0 and engine 10D is in load operation in response to depression of the accelerator pedal by the driver, main ECU170 executes a catalyst temperature increasing routine similar to the catalyst temperature increasing routine shown in fig. 4 and 5. While the catalyst temperature increasing routine is being executed, main ECU170 and MGECU55D control motor generator MG so as to compensate for insufficient drive torque due to fuel cut in some of the cylinders of engine 10D. As a result, the same operational effects as those of the hybrid vehicle 1 and the like can be obtained in the hybrid vehicle 1D. In hybrid vehicle 1D, when the air-fuel ratio in the combustion cylinder is rich, the surplus power of engine 10D may be converted into electric power by motor generator MG, or an increase in the output torque of engine 10D may be suppressed by retarding the ignition timing. In the hybrid vehicle 1D, during execution of the catalyst temperature increase control routine, the downshift (change in the gear ratio) of the transmission 25 may be appropriately performed so that the rotation speed of the engine 10D becomes equal to or higher than the predetermined rotation speed.

Fig. 12 is a schematic configuration diagram showing still another hybrid vehicle 1E of the present disclosure. Of the components of the hybrid vehicle 1E, the same components as those of the hybrid vehicle 1 and the like described above are denoted by the same reference numerals, and redundant description thereof is omitted.

A hybrid vehicle 1E shown in fig. 12 includes an engine (internal combustion engine) 10E including a plurality of cylinders (not shown), a motor generator (synchronous generator motor) MG, a power transmission device 21E, a high-voltage battery 40E, a low-voltage battery (auxiliary battery) 42E, a DC/DC converter 44 connected to the high-voltage battery 40E and the low-voltage battery 42E, an inverter 54 driving the motor generator MG, an engine ECU100E controlling the engine 10E, an MGECU55E controlling the DC/DC converter 44 and the inverter 54, and an HVECU70E controlling the entire vehicle. The engine 10E includes an upstream-side purification device 18 and a downstream-side purification device 19 as exhaust gas purification devices, and the crankshaft 12 of the engine 10E is connected to an input member of a damper mechanism, not shown, included in the power transmission device 21E. Engine 10E includes a starter 130 that outputs cranking torque to crankshaft 12 to start engine 10E.

The rotor of motor generator MG is coupled to an end portion of crankshaft 12 of engine 10E opposite to the side of power transmission device 21E via transmission mechanism 140. In the present embodiment, the transmission mechanism 140 is a winding transmission mechanism, a gear mechanism, or a chain mechanism. Motor generator MG may be disposed between engine 10E and power transmission device 21E, or may be a dc motor. The power transmission device 21E includes, in addition to the damper mechanism, a torque converter (a fluid transmission device), a multi-plate or single-plate lockup clutch, a transmission, a hydraulic control device that adjusts the pressure of hydraulic oil, and the like. The transmission of the power transmission device 21E is a stepped transmission, a mechanical continuously variable transmission, a dual clutch transmission, or the like.

In hybrid vehicle 1E, engine 10E can be started by outputting cranking torque from motor generator MG to crankshaft 12 via power transmission mechanism 140. During traveling of hybrid vehicle 1E, motor generator MG mainly operates as a generator that converts a part of the power from engine 10E in load operation into electric power, and is driven by electric power from high-voltage battery 40E as appropriate to output driving torque (assist torque) to crankshaft 12 of engine 10E. During braking of hybrid vehicle 1E, motor generator MG outputs regenerative braking torque to crankshaft 12 of engine 10E.

In hybrid vehicle 1E as well, while engine 10E is in load operation in response to depression of the accelerator pedal by the driver, the same catalyst temperature increasing routine as that shown in fig. 4 and 5 is executed by engine ECU 100E. While the catalyst temperature increasing routine is being executed, HVECU70E and MGECU55E control motor generator MG so as to compensate for insufficient drive torque due to fuel cut in a part of the cylinders of engine 10E. As a result, the hybrid vehicle 1E can also obtain the same operational effects as the hybrid vehicle 1 and the like. In hybrid vehicle 1E, when the air-fuel ratio in the combustion cylinder is rich, the surplus power of engine 10E may be converted into electric power by motor generator MG, or an increase in the output torque of engine 10E may be suppressed by retarding the ignition timing. In the hybrid vehicle 1E, during execution of the catalyst temperature increase control routine, downshift (change of the gear ratio) of the transmission of the power transmission device 21E may be appropriately performed so that the rotation speed of the engine 10E becomes equal to or higher than the predetermined rotation speed.

As described above, a hybrid vehicle of the present disclosure includes a multi-cylinder engine, an exhaust gas purification device including a catalyst purifying exhaust gas from the multi-cylinder engine, an electric motor, and an electric storage device supplying and receiving electric power to and from the electric motor, wherein at least one of the multi-cylinder engine and the electric motor outputs driving force to wheels, wherein the hybrid vehicle includes a control device executing catalyst temperature increase control for stopping fuel supply to at least any one of cylinders and making an air-fuel ratio in remaining cylinders other than the at least any one of cylinders rich when temperature increase of the catalyst is requested during load operation of the multi-cylinder engine, and controlling the electric motor so as to compensate for insufficient driving force due to execution of the catalyst temperature increase control, the control device changes the air-fuel ratio of at least one of the remaining cylinders to a lean side after the temperature of the exhaust gas purification device becomes equal to or higher than a predetermined determination threshold value during execution of the catalyst temperature increase control.

The control device of a hybrid vehicle according to the present disclosure executes catalyst temperature increase control for stopping fuel supply to at least one of the cylinders of a multi-cylinder engine and making the air-fuel ratio in the remaining cylinders rich, when the temperature increase of a catalyst is requested during load operation of the multi-cylinder engine. Thus, during execution of the catalyst temperature increasing control, relatively much air, i.e., oxygen, is introduced into the exhaust gas purification apparatus from the cylinder to which fuel supply is stopped, and relatively much unburned fuel is introduced into the exhaust gas purification apparatus from the cylinder to which fuel is supplied. As a result, during load operation of the multi-cylinder engine, relatively large amounts of unburned fuel can be reacted in the presence of sufficient oxygen, and the temperature of the catalyst can be sufficiently and rapidly increased by the heat of reaction. When the temperature of the exhaust gas purification apparatus becomes equal to or higher than a predetermined determination threshold, the control device stops the fuel supply to at least one of the cylinders and changes the air-fuel ratio of at least one of the remaining cylinders to the lean side. This makes it possible to supply a large amount of oxygen into the exhaust gas purification device after the temperature has been raised. During execution of the catalyst temperature increasing control, the electric motor is controlled by the control device so as to compensate for the insufficient driving force due to the catalyst temperature increasing control, that is, the stop of the fuel supply to at least one of the cylinders. Thus, during execution of the catalyst temperature increase control, the insufficient driving force due to the stop of fuel supply to some of the cylinders can be compensated with high accuracy and high responsiveness by the motor, and the driving force corresponding to the request can be output to the wheels. Therefore, in the hybrid vehicle of the present disclosure, it is possible to sufficiently and quickly raise the temperature of the catalyst of the exhaust gas purification device and supply a sufficient amount of oxygen to the exhaust gas purification device while suppressing deterioration of drivability during load operation of the multi-cylinder engine.

Further, the control device may change the air-fuel ratio in the remaining cylinders to a lean side after the temperature of the exhaust gas purification device becomes equal to or higher than a 1 st determination threshold during execution of the catalyst temperature increase control, and may stop the supply of fuel to at least any one of the remaining cylinders on condition that the driving force insufficient due to the execution of the catalyst temperature increase control can be compensated by the motor after the temperature of the exhaust gas purification device becomes equal to or higher than a 2 nd determination threshold higher than the 1 st determination threshold. This makes it possible to stably operate the multi-cylinder engine in which the fuel supply to some of the cylinders is stopped, and to supply more oxygen into the exhaust gas purification device having a sufficiently increased temperature.

Further, the control device may stop the supply of fuel to at least any one of the remaining cylinders and change the air-fuel ratio to a lean side in the cylinder in which the supply of fuel in the remaining cylinder is not stopped, on the condition that the driving force insufficient due to the execution of the catalyst temperature increase control can be compensated for by the motor, after the temperature of the exhaust gas purification apparatus becomes equal to or higher than the determination threshold value during the execution of the catalyst temperature increase control. This makes it possible to supply a large amount of oxygen into the exhaust gas purification device after the catalyst has been sufficiently and rapidly warmed.

Further, the control device may be configured to make the air-fuel ratio in the cylinder to which the fuel is supplied rich when the temperature of the exhaust gas purification device becomes lower than a predetermined temperature after changing the air-fuel ratio in at least any one of the remaining cylinders to a lean side. Thus, when the temperature of the exhaust gas purification apparatus decreases due to an increase in the amount of air introduced into the exhaust gas purification apparatus, the temperature of the exhaust gas purification apparatus can be increased again by making the air-fuel ratio in the cylinder to which fuel is supplied rich.

Further, the control device may decrease the number of cylinders in which the fuel supply is stopped when the temperature of the exhaust gas purification device becomes lower than the predetermined temperature after changing the air-fuel ratio of at least any one of the remaining cylinders to a lean side. This reduces the amount of air introduced into the exhaust gas purification device, and suppresses a temperature drop in the exhaust gas purification device.

Further, the control device may execute the catalyst temperature increase control so that fuel is supplied to at least 1 of the cylinders after fuel supply to any one of the cylinders is stopped. Thus, the fuel supply to the plurality of cylinders is not continuously stopped, and therefore, the variation of the torque output from the multi-cylinder engine and the deterioration of the engine noise can be suppressed.

Also, the exhaust gas purifying apparatus may include a particulate trap. In a vehicle including such an exhaust gas purification apparatus, a large amount of oxygen can be introduced from a cylinder in which fuel supply is stopped to a particulate trap that has been heated together with a catalyst, and particulate matter deposited on the particulate trap can be favorably combusted. That is, the catalyst temperature rise control of the present disclosure is extremely useful for regenerating the particulate trap in a low-temperature environment where many particulate matters are likely to accumulate in the particulate trap. The particle trap may be disposed downstream of the catalyst, and may carry the catalyst. In addition, the exhaust gas purification apparatus may include an upstream side purification apparatus that includes a catalyst, and a downstream side purification apparatus that includes at least a particulate trap and is disposed on a downstream side of the upstream side purification apparatus.

In a control method of a hybrid vehicle according to the present disclosure, the hybrid vehicle includes a multi-cylinder engine, an exhaust gas purification device, an electric motor, and an electric storage device that transmits and receives electric power to and from the electric motor, the exhaust gas purification device includes a catalyst that purifies exhaust gas from the multi-cylinder engine, and at least one of the multi-cylinder engine and the electric motor outputs driving force to wheels, in the control method, when temperature rise of the catalyst is requested during load operation of the multi-cylinder engine, catalyst temperature rise control is executed that stops fuel supply to at least any one of cylinders and makes an air-fuel ratio in remaining cylinders other than the at least any one cylinder rich, and the electric motor is controlled so as to compensate for insufficient driving force due to execution of the catalyst temperature rise control, and in the execution of the catalyst temperature rise control, and changing the air-fuel ratio of at least one of the remaining cylinders to a lean side after the temperature of the exhaust gas purification device becomes equal to or higher than a predetermined determination threshold.

According to this method, it is possible to sufficiently and quickly raise the temperature of the catalyst of the exhaust gas purification device and supply a sufficient amount of oxygen to the exhaust gas purification device while suppressing deterioration of drivability during load operation of the multi-cylinder engine.

The invention of the present disclosure is not limited to the above-described embodiments at all, and it goes without saying that various modifications are possible within the scope of the extension of the present disclosure. The above embodiment is merely a specific embodiment of the invention described in the summary of the invention, and does not limit the elements of the invention described in the summary of the invention.

The invention disclosed herein can be utilized in the manufacturing industry of hybrid vehicles and the like.