阅读说明：本技术 发动机装置及具备该发动机装置的混合动力车 (Engine device and hybrid vehicle provided with same ) 是由 野濑勇喜 小林正明 于 2021-04-08 设计创作，主要内容包括：一种发动机装置及具备该发动机装置的混合动力车,所述发动机装置具备能够向每个气缸喷射燃料的发动机、净化发动机的排气的净化装置、以及在发动机的低温起动时执行增加燃料喷射量的低温起动控制的控制装置,在所述发动机装置中,控制装置在低温起动控制期间进行了净化装置的升温请求时,在低温起动控制中的燃料增量达到第1规定量以下之后,执行对发动机的一部分气缸切断燃料,并且对其他气缸增加燃料的升温控制。(In an engine device including an engine capable of injecting fuel into each cylinder, a purification device purifying exhaust gas of the engine, and a control device executing low-temperature start control for increasing a fuel injection amount at the time of low-temperature start of the engine, the control device executes temperature increase control for cutting off fuel to some cylinders of the engine and increasing fuel to other cylinders after a fuel increase amount in the low-temperature start control reaches a 1 st predetermined amount or less when a temperature increase request of the purification device is made during the low-temperature start control.)

1. An engine device, characterized by comprising:

an engine capable of injecting fuel to each cylinder;

a purification device that purifies exhaust gas of the engine; and

a control device that executes a low-temperature start control that increases a fuel injection amount at a low-temperature start of the engine,

the control device executes temperature increase control of cutting off fuel to some cylinders of the engine and adding fuel to other cylinders after a fuel increase amount in the low-temperature start control reaches a 1 st prescribed amount or less when a temperature increase request of the purge device is made during the low-temperature start control.

2. The engine apparatus according to claim 1,

the control device changes the cylinder in which fuel is cut every predetermined period after the fuel increase amount in the low-temperature start control reaches a 2 nd predetermined amount or less which is smaller than the 1 st predetermined amount as the temperature increase control.

3. The engine apparatus according to claim 1 or 2,

the control means performs the fuel increase to the other cylinder in the temperature raising control in a gradual manner.

4. A hybrid vehicle, characterized in that,

the vehicle is provided with the engine device according to any one of claims 1 to 3 and a motor capable of outputting power for traveling, and travels using the power from the engine device and the power from the motor,

the control means also controls the electric motor,

the control device performs control so that the output torque from the electric motor is increased when the temperature rise control is executed.

Technical Field

The present invention relates to an engine device and a hybrid vehicle including the same.

Background

Conventionally, as such an engine device, a device has been proposed which controls the engine in a temperature increase mode when temperature increase of a catalyst device for purifying exhaust gas of the engine is required (for example, refer to japanese patent application laid-open No. 2004-218541). In the temperature raising mode, the engine is controlled such that the air-fuel ratio of a part of the cylinders becomes richer than the stoichiometric air-fuel ratio and the air-fuel ratio of the remaining cylinders becomes leaner than the stoichiometric air-fuel ratio.

Disclosure of Invention

As an engine device including a purification device for purifying exhaust gas, there is an engine device in which fuel is cut off for some cylinders of an engine and fuel is added to other cylinders when the temperature of the purification device is raised. In general, when the engine is started at a low temperature, fuel is increased in consideration of the adhesion of fuel to the intake port or the cylinder wall surface. If a request for temperature rise of the purge device is made at the time of such low-temperature start, the fuel increase amount at the time of low-temperature start overlaps with the fuel increase amount associated with fuel cut of some of the cylinders, or inflow of the fuel deposit amount of the cylinders in which fuel cut is performed occurs, with respect to the cylinders in which fuel cut is not performed, and the accuracy of the air-fuel ratio is lowered.

The engine device and the hybrid vehicle including the same according to the present invention are mainly intended to suppress a decrease in accuracy of an air-fuel ratio when a request for fuel cut of a part of cylinders of an engine to raise a temperature of a purifier is made when the engine is started at a low temperature.

The engine device and the hybrid vehicle including the engine device of the present invention employ the following means in order to achieve the main object described above.

An engine device according to the present invention is characterized by comprising:

an engine capable of injecting fuel to each cylinder;

a purification device that purifies exhaust gas of the engine; and

a control device that executes a low-temperature start control that increases a fuel injection amount at a low-temperature start of the engine,

the control device executes temperature increase control of cutting off fuel to some cylinders of the engine and adding fuel to other cylinders after a fuel increase amount in the low-temperature start control reaches a 1 st prescribed amount or less when a temperature increase request of the purge device is made during the low-temperature start control.

In the engine apparatus of the present invention, the fuel injection amount is increased at the time of low-temperature start of the engine. When a temperature increase request of the purge device is made during the low-temperature start control, after the fuel increase amount in the low-temperature start control reaches a 1 st predetermined amount or less, temperature increase control is executed in which fuel is cut off to some of the cylinders of the engine and fuel is added to the other cylinders. Thus, even if the fuel increase amount at the time of low-temperature start overlaps with the fuel increase amount associated with the fuel cut of the partial cylinder by cutting the fuel to the partial cylinder of the engine at the time of low-temperature start of the engine, it is possible to suppress a decrease in the accuracy of the air-fuel ratio as compared with the case where the fuel is cut to the partial cylinder of the engine when the fuel increase amount at the time of low-temperature start exceeds the 1 st predetermined amount. Here, the "partial cylinder" may be 1 cylinder, or may be 2 or more cylinders.

In the engine apparatus according to the present invention, the controller may change the cylinder in which the fuel is cut every predetermined period after the fuel increase amount in the low-temperature start control reaches a 2 nd predetermined amount or less smaller than the 1 st predetermined amount as the temperature increase control. In this way, the thermal imbalance of the engine can be suppressed. Here, the "predetermined period" may be a period in which a predetermined time has elapsed or a period in which the rotor has rotated a predetermined number of times.

In the engine apparatus of the present invention, the control device may perform the fuel increase to the other cylinder in the temperature raising control in a gradual manner. In this case, a decrease in the accuracy of the air-fuel ratio can be suppressed as compared with a case where the fuel increase amount is changed abruptly.

The hybrid vehicle of the invention is characterized in that:

an engine apparatus according to the present invention having an engine apparatus and a motor capable of outputting power for traveling using power from the engine apparatus and power from the motor for traveling, the engine apparatus basically including an engine capable of injecting fuel into each cylinder, a purification apparatus purifying exhaust gas from the engine, and a control apparatus performing low-temperature start control for increasing a fuel injection amount at the time of low-temperature start of the engine, the control apparatus performing temperature increase control for cutting off fuel for some cylinders of the engine and increasing fuel for other cylinders after a fuel increase amount in the low-temperature start control reaches a 1 st predetermined amount or less when a temperature increase request from the purification apparatus is made during the low-temperature start control,

the control means also controls the electric motor,

the control device performs control so that the output torque from the electric motor is increased when the temperature rise control is executed.

In the hybrid vehicle according to the present invention, since the engine device according to the present invention according to any one of the aspects of the present invention is provided, the effect achieved by the engine device according to the present invention, that is, the effect of suppressing the decrease in the accuracy of the air-fuel ratio can be achieved. Further, since the control is performed so that the output torque from the electric motor becomes larger when the temperature raising control is executed, at least a part of the driving force that is insufficient due to the fuel cut of a part of the cylinders of the engine can be supplemented by the increase in the output torque from the electric motor. As a result, a decrease in driving force when fuel is cut off to some of the cylinders of the engine can be suppressed.

Drawings

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 wherein:

fig. 1 is a schematic configuration diagram showing a configuration of a hybrid vehicle 20 in which an engine apparatus according to an embodiment of the present invention is mounted.

Fig. 2 is a schematic configuration diagram showing a configuration of the engine 22.

Fig. 3 is a flowchart showing an example of a temperature increase control routine executed by the engine ECU24 when increasing the temperature of the PM filter 136 during low-temperature start of the engine 22.

Fig. 4 is an explanatory diagram for explaining an example of the increase Δ F1 at the time of low-temperature start, the implementation of fuel cut for 1 cylinder, and the temporal change in the alternate cycle of the Fuel Cut (FC) cylinder.

Fig. 5 is a schematic configuration diagram showing a configuration of a hybrid vehicle 220 according to a modification.

Fig. 6 is a schematic configuration diagram showing a configuration of a hybrid vehicle 320 according to a modification.

Fig. 7 is a schematic configuration diagram showing a configuration of a hybrid vehicle 420 according to a modification.

Detailed Description

Next, embodiments of the present invention will be described with reference to examples.

Fig. 1 is a schematic configuration diagram showing a configuration of a hybrid vehicle 20 in which an engine apparatus according to an embodiment of the present invention is mounted. As shown in the drawing, the hybrid vehicle 20 of the embodiment includes an engine 22, an engine ECU24, a planetary gear 30, motors MG1, MG2, inverters 41, 42, a battery 50 as a power storage device, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

The engine 22 is a multi-cylinder (e.g., 4-cylinder, 6-cylinder, etc.) internal combustion engine that outputs power using gasoline, diesel, etc. as fuel, and is connected to a carrier of a planetary gear 30 via a damper 28. Fig. 2 is a schematic configuration diagram showing a configuration of the engine 22. As shown in the drawing, the engine 22 takes air purified by an air cleaner 122 into an intake pipe 123 to pass through a throttle valve 124, and injects fuel from a fuel injection valve 126 provided for each cylinder, mixes the air and the fuel, and takes the mixture into a combustion chamber 129 via an intake valve 128. Then, the intake air-fuel mixture is explosively combusted by an electric spark generated by the ignition plug 130 attached to each of the cylinders, and the reciprocating motion of the piston 132 pushed down by its energy is converted into the rotational motion of the crankshaft 26. The engine 22 has a fuel injection valve 126 that injects fuel into each cylinder, and therefore can perform fuel cut-off for each cylinder. Is discharged from combustion chamber 129 to exhaust pipe 133 via exhaust valve 131The discharged exhaust Gas is discharged to the outside air via the catalyst device 134 and the PM filter 136, and is supplied to the intake side via an exhaust Gas recirculation device (hereinafter referred to as an "egr (exhaust Gas recirculation) system") 160 that recirculates the exhaust Gas to the intake air. The catalyst device 134 has a function of purifying carbon monoxide (CO), Hydrocarbons (HC), and Nitrogen Oxides (NO) in the exhaust gas_X) A purification catalyst (three-way catalyst) 134a for harmful components. The PM filter 136 is formed as a porous filter of ceramic, stainless steel, or the like, and traps Particulate Matter (PM) such as soot in the exhaust gas. In the embodiment, the catalyst device 134 and the PM filter 136 correspond to a "purification device". The EGR system 160 includes an EGR pipe 162 connected to a rear stage of the catalyst device 134 to supply exhaust gas to an intake-side surge tank, and an EGR valve 164 disposed in the EGR pipe 162 and driven by a stepping motor 163. In the EGR system 160, the opening degree of the EGR valve 164 is adjusted to adjust the amount of recirculation of the exhaust gas, which is a non-combusted gas, to the intake side.

The engine ECU24 is a microprocessor including a CPU24a as its center, and includes a ROM24b storing processing programs, a RAM24c temporarily storing data, an input/output port and a communication port, not shown, in addition to the CPU24 a.

Signals from various sensors that detect the state of the engine 22 are input to the engine ECU24 via an input port. Examples of the signal input to engine ECU24 include a crank position from crank position sensor 140 that detects a rotational position of crankshaft 26, and an engine water temperature Thw from water temperature sensor 142 that detects a temperature of cooling water of engine 22. Further, the engine oil temperature Thoi from an oil temperature sensor 143 that detects the temperature of the engine oil, and the cam position from a cam position sensor 144 that detects the rotational position of a camshaft that opens and closes an intake valve 128 that takes in air to a combustion chamber and an exhaust valve that exhausts air from the combustion chamber may be mentioned. Further, the throttle opening TH from a throttle position sensor 146 that detects the position of the throttle valve 124, the intake air amount Qa from an air flow meter 148 attached to the intake pipe, the intake air temperature Ta from a temperature sensor 149 also attached to the intake pipe, and the intake air pressure Pin from an intake air pressure sensor 158 that detects the pressure in the intake pipe may be mentioned. Further, the catalyst temperature Tc from the temperature sensor 134a attached to the catalyst device 134, the air-fuel ratio AF from the air-fuel ratio sensor 135a, the oxygen signal O2 from the oxygen sensor 135b, and the differential pressure Δ P from the differential pressure sensor 136a that detects the differential pressure before and after the PM filter 136 (the differential pressure on the upstream side and the downstream side) may be mentioned. An EGR valve opening degree EV from an EGR valve opening degree sensor 165 that detects the opening degree of the EGR valve 164 may also be exemplified.

Various control signals for driving the engine 22 are output from the engine ECU24 via an output port. Examples of the signal output from the engine ECU24 include a drive signal to the fuel injection valve 126, a drive signal to a throttle motor 136 that adjusts the position of the throttle valve 124, and a control signal to an ignition coil 138 integrated with an igniter. Further, a control signal to the variable valve timing mechanism 150 that can change the opening/closing timing of the intake valve 128, a drive signal to the stepping motor 163 that adjusts the opening degree of the EGR valve 164, and the like may be mentioned.

The engine ECU24 communicates with the hybrid electronic control unit 70, performs operation control of the engine 22 in accordance with control signals from the hybrid electronic control unit 70, and outputs data relating to the operating state of the engine 22 as needed.

The engine ECU24 calculates the rotation speed Ne of the engine 22 based on the crank angle θ cr from the crank position sensor 140, or calculates the temperature (catalyst temperature) Tc of the purification catalyst 134a of the catalyst device 134 based on the cooling water temperature Tw or the like from the water temperature sensor 142. Further, the engine ECU24 calculates a load factor KL (a ratio of the volume of air actually taken in 1 cycle to the stroke volume per 1 cycle of the engine 22) based on the intake air amount Qa from the air flow meter 148 and the rotation speed Ne of the engine 22. Further, the engine ECU24 calculates a PM deposition amount Qpm, which is a deposition amount of particulate matter deposited on the PM filter 136, based on the differential pressure Δ P from the differential pressure sensor 136a, or calculates a filter temperature Tf, which is a temperature of the PM filter 136, based on the rotation speed Ne and the load factor KL of the engine 22.

As shown in fig. 1, the planetary gear 30 is configured as a single-pinion planetary gear mechanism, and includes a sun gear 31, a ring gear 32, a plurality of pinion gears 33 that mesh with the sun gear 31 and the ring gear 32, respectively, and a carrier 34 that supports the plurality of pinion gears 33 so as to rotate (rotate) and revolve freely. A rotor of the motor MG1 is connected to the sun gear 31 of the planetary gear 30. A drive shaft 36 coupled to drive wheels 39a, 39b via a differential gear 38 is connected to the ring gear 32 of the planetary gear 30. As described above, the crankshaft 26 of the engine 22 is connected to the carrier 34 of the planetary gear 30 via the damper 28.

The motor MG1 is configured as a synchronous generator-motor, for example, and the rotor is connected to the sun gear 31 of the planetary gear 30 as described above. The motor MG2 is configured as a synchronous generator motor, for example, and the rotor is connected to the drive shaft 36. The inverters 41, 42 are used for driving the motors MG1, MG2, and are connected to the battery 50 via the power line 54. A smoothing capacitor 57 is mounted on the power line 54. The motors MG1, MG2 are rotationally driven by switching control of a plurality of switching elements (not shown) of the inverters 41, 42 by a motor electronic control unit (hereinafter referred to as "motor ECU") 40.

Although not shown, the motor ECU40 is configured as a microprocessor including a CPU as a center, and includes a ROM that stores processing programs, a RAM that temporarily stores data, an input/output port, and a communication port in addition to the CPU. Signals from various sensors necessary for drive control of the motors MG1, MG2 are input to the motor ECU40 via the input port, and for example, phase currents Iu1, Iv1, Iu2, Iv2 from rotational position detection sensors 43, 44 that detect rotational positions of rotors of the motors MG1, MG2, and phase currents Iu1, θ m2 from current sensors 45u, 45v, 46u, 46v that detect currents flowing through respective phases of the motors MG1, MG2, and the like are input. Switching control signals and the like for the plurality of switching elements of inverters 41 and 42 are output from motor ECU40 via an output port. The motor ECU40 and the HVECU70 are connected via a communication port. The motor ECU40 calculates the electrical angles θ e1, θ e2, the angular velocities ω m1, ω m2, the rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θ m1, θ m2 of the rotors of the motors MG1, MG2 from the rotational position detection sensors 43, 44.

The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as "battery ECU") 52.

Although not shown, the battery ECU52 is configured as a microprocessor including a CPU as a center, and includes a ROM that stores processing programs, a RAM that temporarily stores data, an input/output port, and a communication port in addition to the CPU. Signals from various sensors required to manage the battery 50 are input to the battery ECU52 via the input port. Examples of the signal input to the battery ECU52 include a voltage Vb of the battery 50 from a voltage sensor 51a attached to terminals of the battery 50, a current Ib of the battery 50 from a current sensor 51b attached to an output terminal of the battery 50, and a temperature Tb of the battery 50 from a temperature sensor 51c attached to the battery 50. The battery ECU52 and the HVECU70 are connected via a communication port. Battery ECU52 calculates power storage ratio SOC based on the integrated value of current Ib of current 50 from current sensor 51 b. The charge rate SOC is a rate of the amount of electricity that can be discharged from the battery 50 relative to the total capacity of the battery 50.

Although not shown, the HVECU70 is configured as a microprocessor including a CPU as a center, and includes a ROM that stores processing programs, a RAM that temporarily stores data, an input/output port, and a communication port in addition to the CPU. Signals from various sensors are input to the HVECU70 via the input port. Examples of the signal input to the HVECU70 include an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81. Further, the accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, the brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and the vehicle speed V from a vehicle speed sensor 88 may be mentioned. The atmospheric pressure Pout from the atmospheric pressure sensor 89 may be mentioned. As described above, the HVECU70 is connected with the engine ECU24, the motor ECU40, and the battery ECU52 via the communication ports.

The hybrid vehicle 20 of the embodiment thus configured travels while switching (while intermittently operating the engine 22) between the hybrid travel mode (HV travel mode) in which the vehicle travels with the operation of the engine 22 and the electric travel mode (EV travel mode) in which the vehicle travels with the operation of the engine 22 stopped.

When the vehicle is in the HV running mode, basically, the HVECU70 sets a running torque Td £ required for running (required by the drive shaft 36) based on the accelerator opening Acc and the vehicle speed V, and calculates a running power Pd @ required for running by multiplying the set running torque Td @ by the rotation speed Nd of the drive shaft 36 (rotation speed Nm2 of the motor MG 2). Then, a target power Pe of the engine 22 is calculated by subtracting a required charge/discharge power Pb of the battery 50 (a positive value when discharged from the battery 50) from the power Pd < SP >, and a target rotation speed Ne < SP >, a target torque Te < SP >, and torque commands Tm1 < SP >, Tm2 < SP > for the motors MG1, MG2 are set so that the calculated target power Pe < SP > is output from the engine 22 and a running torque Td < SP > is output to the drive shaft 36. Then, the target rotation speed Ne and the target torque Te of the engine 22 are transmitted to the engine ECU24, and the torque commands Tm1 and Tm2 for the motors MG1 and MG2 are transmitted to the motor ECU 40. When engine ECU24 receives a target rotation speed Ne and a target torque Te of engine 22, engine ECU 22 controls the operation of engine 22 so that engine 22 operates based on the target rotation speed Ne and the target torque Te. As the operation control of the engine 22, an intake air amount control for controlling the opening degree of the throttle valve 124, a fuel injection control for controlling the fuel injection amount from the fuel injection valve 126, an ignition control for controlling the ignition timing of the ignition plug 130, and the like are performed. In the fuel injection control, a value obtained by multiplying a basic fuel injection amount Qf based on the rotation speed of the engine 22 and the intake pipe pressure by a correction coefficient based on various sensor values for detecting the state of the engine 22 is set as a target injection amount Qf, and the fuel injection valve 126 provided in each cylinder is controlled so that the fuel injection amount from the fuel injection valve 126 becomes the target injection amount Qf. Upon receiving torque commands Tm1 and Tm2 for motors MG1 and MG2, motor ECU40 controls switching of the plurality of switching elements of inverters 41 and 42 so that motors MG1 and MG2 are driven by torque commands Tm1 and Tm 2.

In the EV running mode, the HVECU70 sets a running torque Td based on the accelerator opening Acc and the vehicle speed V, sets a torque command Tm1 for the motor MG1 to a value of 0, sets a torque command Tm2 for the motor MG2 so as to output the running torque Td to the drive shaft 36, and transmits torque commands Tm1 and Tm2 for the motors MG1 and MG2 to the motor ECU 40. The control of the inverters 41, 42 by the motor ECU40 is as described above.

Next, the operation of the hybrid vehicle 20 configured as described above, particularly, the operation when the temperature of the catalyst device 134 and the PM filter 136 is raised during the low-temperature start of the engine 22, will be described. For simplicity of description, the following description will be made assuming a case where the temperature of the PM filter 136 is increased. The PM filter 136 regenerates when the PM accumulation amount Qpm, which is the accumulation amount of the accumulated particulate matter, becomes equal to or greater than the threshold value Qpmref. In the regeneration of the PM filter 136, the PM filter 136 is heated to a temperature (filter temperature) Tf at which the temperature (filter temperature) Tf becomes equal to or higher than a threshold value Tref, and then air is supplied to the PM filter 136, whereby the accumulated particulate matter is burned and regenerated. Here, the threshold value Qpmref is the lower limit of the PM accumulation amount range in which it can be judged that regeneration of the PM filter 136 is necessary, and for example, 3g/L, 4g/L, 5g/L, or the like can be used. The threshold value Tfref is a lower limit Tmin of a regeneration temperature range suitable for regeneration of the PM filter 136, and may be 580 ℃, 600 ℃, 620 ℃, or the like, for example. The temperature increase of the PM filter 136 is performed by cutting off fuel to 1 cylinder of the cylinders of the engine 22 in the embodiment. The particulate matter accumulated in the PM filter 136 is burned by cutting fuel to all cylinders of the engine 22. Fig. 3 is a flowchart showing an example of a temperature increase control routine executed by the engine ECU24 when increasing the temperature of the PM filter 136 during low-temperature start of the engine 22. This routine is repeated at predetermined time intervals.

When executing the temperature increase control routine, the engine ECU24 first inputs data such as the PM accumulation amount Qpm, the filter temperature Tf, and the cold start increase amount Δ F1 (step S100). Here, the values calculated by the engine ECU24 may be input as the PM accumulation amount Qpm and the filter temperature Tf. The low-temperature start increase Δ F1 is an increase in the fuel injection amount determined by the temperature of the cooling water at the time of starting the engine 22 (the start-time cooling water temperature), the temperature of the cooling water at that time (the current water temperature), the integrated air amount after starting, the engine load factor, and the like, and can be input with a value calculated by the fuel injection control.

Then, it is determined whether the 1-cylinder fuel cut condition is established (step S110). That is, it is determined whether the temperature of the PM filter 136 needs to be increased for regeneration of the PM filter 136. Specifically, it is determined whether the PM accumulation amount Qpm is equal to or greater than the threshold value Qpmref and whether the filter temperature Tf is less than the threshold value Tfref. When the PM accumulation amount Qpm is smaller than the threshold value Qpmref, the regeneration of the PM filter 136 is not necessary, and therefore it is determined that the 1-cylinder fuel cut condition is not satisfied. When the PM accumulation amount Qpm is equal to or greater than the threshold value Qpmref and the filter temperature Tf is less than the threshold value Tfref, regeneration of the PM filter 136 is required, so a temperature rise of the PM filter 136 is required, and it is determined that the 1-cylinder fuel cut condition is satisfied. When the PM accumulation amount Qpm is equal to or greater than the threshold value Qpmref and the filter temperature Tf is equal to or greater than the threshold value Tfref, regeneration of the PM filter 136 is necessary, but the temperature rise of the PM filter 136 is not necessary, and it is determined that the 1-cylinder fuel cut condition is not satisfied. Further, since the cold start of the engine 22 is taken into consideration, it is not necessary to consider the case where the filter temperature Tf is equal to or higher than the threshold value Tfref. When it is determined in step S110 that the 1-cylinder fuel cut condition is not satisfied, the present routine is ended. That is, the normal low-temperature start of the engine 22 is performed without performing the 1-cylinder fuel cut.

When it is determined in step S110 that the 1-cylinder fuel cut condition is satisfied, it is determined whether a 1-cylinder fuel cut has been performed (step S120). Since it is now assumed that the 1-cylinder fuel cut is not performed immediately after the low-temperature start of the engine 22, the determination at step S120 is no. In this case, it is determined whether or not the low-temperature start-time increase amount Δ F1 is equal to or less than the threshold a (step S130), and if it is determined that the low-temperature start-time increase amount Δ F1 is greater than the threshold a, the routine is ended without starting the execution of the 1-cylinder fuel cut. In this case, a normal low-temperature start of the engine 22 is also performed. The threshold value A may be, for example, a value in the range of 70 to 120% increments (1.7 to 2.2 times the normal fuel injection amount).

On the other hand, when it is determined in step S130 that the cold start time increase Δ F1 is equal to or less than the threshold value a, fuel cut (1-cylinder fuel cut) is performed only for 1 of the cylinders of the engine 22 and the output torque of the motor MG2 is increased (step S140). In the 1-cylinder fuel cut implementation, fuel is added to the cylinders (combustion cylinders) that do not perform fuel cut among the cylinders of the engine 22. The increase amount Δ F2 at this time is mostly within the range of 0 to 33% in the case of a 4-cylinder engine, and is mostly within the range of 0 to 20% in the case of a 6-cylinder engine. The fuel increase in the combustion cylinder associated with the 1-cylinder fuel cut is preferably performed in a gradual manner. For example, when the increment Δ F is a 20% increment, the increment is increased so as to be a 20% increment in 5 cycles or 7 cycles. The amount of increase in the output torque of the motor MG2 is preferably a driving force corresponding to a decrease in the output from the engine 22 generated by cutting off fuel to 1 cylinder. The output torque of the motor MG2 is increased by requesting the HVECU70 from the engine ECU24 for an increase in the output torque of the motor MG2 associated with the 1-cylinder fuel cut, requesting the motor ECU40 for the output torque of the motor MG2 from the HVECU70 based on the request, and executing the increase in the output torque of the motor MG2 by the motor ECU 40.

Next, it is determined whether or not the low-temperature start increase Δ F1 is equal to or less than the threshold B (step S150). The threshold value B is smaller than the threshold value a, and may be, for example, a value in the range of 40 to 80% increments (1.4 to 1.8 times the normal fuel injection amount). When it is determined that the cold start increase Δ F1 is equal to or less than the threshold value B, the fuel cut cylinder alternation cycle is started, that is, the fuel cut cylinders among the cylinders of the engine 22 are sequentially changed (step S160), and the routine is ended. The alternate cycle of the fuel cut cylinder is performed so that the cylinder in which fuel is cut is changed every predetermined period. The predetermined period may be a period in which a predetermined time such as 1 second or 2 seconds has elapsed, a period in which the apparatus is rotated for a predetermined number of turns such as 25 turns or 50 turns, or a period in which the apparatus is rotated for 10 cycles or 25 cycles. In the embodiment, the counter C is incremented by 1 for every 1 cycle by the cycle counter C, and the counter C is reset to change the fuel cut cylinder when the counter C reaches the threshold Cref (for example, 10, 15, 20, 25). If the fuel cut cylinders are alternately circulated as such, thermal imbalance of the engine 22 can be avoided. If it is determined in step S150 that the cold start time increase Δ F1 is greater than the threshold value B, the routine is ended without starting the alternate cycle of the fuel cut cylinder.

When it is determined in step S120 that the 1-cylinder fuel cut has been performed (during execution), the 1-cylinder fuel cut has been performed, and therefore the process proceeds to step S150 without performing the determination of the start of the 1-cylinder fuel cut (step S130) or the process of the start of the 1-cylinder fuel cut (step S140).

When the temperature Tf of the PM filter 136 becomes equal to or higher than the threshold value Tfref by the temperature increase control, the PM filter 136 is regenerated so that the accumulated particulate matter is burned by supplying air to the PM filter 136 by fuel cut in all the cylinders, fuel cut in a plurality of cylinders, or the like, as described above.

Fig. 4 is an explanatory diagram for explaining an example of the increase Δ F1 at the time of low-temperature start, the implementation of fuel cut for 1 cylinder, and the temporal change in the alternate cycle of the fuel cut cylinder. The engine 22 is started at a low temperature at time T0, and when the low-temperature start increase Δ F1 reaches the threshold value a at time T1, a 1-cylinder fuel cut is performed to cut fuel to the No. 1 cylinder. At this time, the increase Δ F2 in fuel is performed for cylinders No. 2 to No. 4, but the increase Δ F2 is performed to increase over several cycles. When the cold start increment Δ F1 reaches the threshold B at time T2, the alternating cycle of fuel cut cylinders is started and the count of the counter C is started. Thereafter, at times T3, T4, T5. cndot. at which the counter C reaches the threshold value Cref, the fuel cut cylinder is changed to cylinder 3, cylinder 4, and cylinder 2.

In the engine apparatus mounted on the hybrid vehicle 20 of the embodiment described above, when the temperature of the PM filter 136 needs to be raised at the time of low-temperature start of the engine 22, the 1-cylinder fuel cut is performed after the increase Δ F1 at the time of low-temperature start reaches the threshold value a or less. Thus, by performing the 1-cylinder fuel cut at the time of low-temperature start of the engine 22, even if the low-temperature start increase amount Δ F1 and the fuel increase amount Δ F2 associated with the 1-cylinder fuel cut overlap, it is possible to suppress a decrease in the accuracy of the air-fuel ratio, as compared to the case where the 1-cylinder fuel cut is performed when the low-temperature start increase amount Δ F1 is greater than the threshold value a. In addition, although the fuel increase amount Δ F2 is performed in the combustion cylinder in which fuel is not cut with the 1-cylinder fuel cut, the increase amount Δ F2 is increased in a gradual manner, so that a decrease in the accuracy of the air-fuel ratio can be suppressed.

In the hybrid vehicle 20 of the embodiment, the output torque of the motor MG2 is increased when the 1-cylinder fuel cut is performed, so it is possible to suppress a decrease in the driving force accompanying the 1-cylinder fuel cut.

In the hybrid vehicle 20 of the embodiment, only 1 cylinder out of the cylinders of the engine 22 is used as the fuel-cut cylinder for raising the temperature of the PM filter 136, but 2 or more cylinders out of the cylinders of the engine 22 may be used as the fuel-cut cylinder. In this case, the fuel cut may be started simultaneously for a plurality of cylinders, or the number of cylinders in which fuel is cut may be increased in stages. In these cases, the amount of increase in the output torque of the motor MG2 is preferably a driving force corresponding to the number of cylinders in which fuel is cut.

Although the engine 22 is described as a 4-cylinder engine in the embodiment, it may be any multi-cylinder engine such as a 6-cylinder engine or an 8-cylinder engine.

In the engine apparatus of the embodiment, the fuel increase amount Δ F2 is set to an increase that increases in a gradual manner in the combustion cylinders in which fuel is not cut with 1-cylinder fuel cut, but may be set to an increase that increases in a rapid manner.

Although the temperature of the PM filter 136 is increased in the engine apparatus of the embodiment, the temperature of the catalyst device 134 may be increased in the same manner.

In the hybrid vehicle 20 of the embodiment, although the battery 50 is used as the power storage device, a capacitor may be used as the power storage device instead of the battery 50.

The hybrid vehicle 20 of the embodiment is configured such that the engine 22 and the motor MG1 are connected to the drive shaft 36 coupled to the drive wheels 39a, 39b via the planetary gear 30, the motor MG2 is connected to the drive shaft 36, and the battery 50 is connected to the motors MG1, MG2 via the electric power line. However, as shown in a hybrid vehicle 220 of a modification example of fig. 5, a so-called 1-motor hybrid vehicle may be configured in which a motor MG is connected to a drive shaft 36 coupled to drive wheels 39a and 39b via a transmission 230, an engine 22 is connected to the motor MG via a clutch 229, and a battery 50 is connected to the motor MG via an electric power line. As shown in a hybrid vehicle 320 of a modification of fig. 6, a so-called series hybrid vehicle may be configured in which a motor MG1 for power generation is connected to the engine 22, a motor MG2 for traveling is connected to the drive shaft 36 coupled to the drive wheels 39a, 39b, and the battery 50 is connected to the motors MG1, MG2 via an electric power line. Further, as shown in a hybrid vehicle 420 of a modification example of fig. 7, a so-called gasoline car may be configured in which the engine 22 is connected to the drive shaft 36 coupled to the drive wheels 39a, 39b via a transmission 430.

The correspondence relationship between the main elements of the embodiments and the main elements of the invention described in the section of technical means for solving the problems will be described. In the embodiment, the engine 22 corresponds to an "engine", the catalyst device 134 and the PM filter 136 correspond to a "purification device", and the engine ECU24 corresponds to a "control device".

In addition, regarding the correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the section of the technical means for solving the problem, the embodiment is an example for specifically explaining the embodiment of the invention described in the section of the technical means for solving the problem, and therefore, the elements of the invention described in the section of the technical means for solving the problem are not limited. That is, the invention described in the section of the technical means for solving the problem is to be explained based on the description in the section, and the examples are merely specific examples of the invention described in the section of the technical means for solving the problem.

While the embodiments of the present invention have been described above with reference to the examples, it is needless to say that the present invention is not limited to the examples, and can be carried out in various ways within a range not departing from the gist of the present invention.

The present invention can be used in the manufacturing industry of engine apparatuses and hybrid vehicles.