阅读说明：本技术 混动发动机启动阶段的怠速控制方法 (Idle speed control method for hybrid engine in starting stage ) 是由 龚静怡 于涛 王华武 赵峰 马彪 任卫群 杨小波 李春东 于 2021-07-28 设计创作，主要内容包括：本发明涉及混动发动机启动阶段的怠速控制方法,包含步骤：采集荷电状态值、油门开度值、油门扭矩请求值、油门变化率值、发动机当前转速值、车速值；拖起发动机转动,至发动机第一转速值；获得发动机目标扭矩；查找人发动机目标扭矩对应喷油量值；查找喷油量值对应发动机转速值；达到发动机执行转速值；驱动电机输出扭矩达到驱动电机目标扭矩；如发动机当前转速值不低于发动机稳定输出转速值,且车速值不低于发动机稳定输出车速值,则流程结束。本发明协调发动机和驱动电机在怠速控制上的工作配合,更适于混动汽车；直接取消PID控制,缩短时延；节省燃油；发动机从喷油开始即输出功率；减少离合器磨损。(The invention relates to an idle speed control method in a hybrid engine starting stage, which comprises the following steps: collecting a charge state value, an accelerator opening value, an accelerator torque request value, an accelerator change rate value, a current engine rotating speed value and a vehicle speed value; dragging the engine to rotate until the engine reaches a first rotating speed value; obtaining an engine target torque; searching the corresponding oil injection quantity value of the target torque of the engine; searching the engine rotating speed value corresponding to the oil injection quantity value; reaching the engine execution speed value; the output torque of the driving motor reaches the target torque of the driving motor; and if the current rotating speed value of the engine is not lower than the stable output rotating speed value of the engine and the vehicle speed value is not lower than the stable output vehicle speed value of the engine, ending the process. The invention coordinates the work coordination of the engine and the driving motor on the idle speed control, and is more suitable for hybrid vehicles; PID control is directly cancelled, and time delay is shortened; fuel oil is saved; the engine outputs power from the beginning of oil injection; and the wear of the clutch is reduced.)

1. An idle speed control method in a hybrid engine start phase, characterized in that: comprises the following steps:

s100, continuously collecting a charge state value, an accelerator opening value, an accelerator torque request value, an accelerator change rate value, a current engine rotating speed value and a vehicle speed value;

s200, starting a starter from the moment of receiving an ignition signal sent by a driver; the method comprises the steps that a starter is used for dragging an engine to rotate until the current rotating speed value of the engine is increased from 0 to a first rotating speed value of the engine, the starter is separated from the engine, and meanwhile the engine starts to inject oil and rotate;

s300, obtaining an engine target torque according to the state of charge value, the accelerator opening value, the accelerator torque request value and the accelerator change rate value;

s400, finding an oil injection quantity value corresponding to the target torque of the engine in an engine torque-oil injection quantity corresponding table preset in an ECU (electronic control Unit); then setting a target fuel injection quantity value equal to the fuel injection quantity value;

s500, searching an engine rotating speed value corresponding to the oil injection quantity value in an engine oil injection quantity-rotating speed corresponding table preset in an ECU (electronic control Unit); then setting an engine execution rotating speed value equal to the engine rotating speed value;

s600, controlling an engine to rotate to enable the current rotating speed value of the engine to reach the execution rotating speed value of the engine; simultaneously controlling the driving motor to rotate, so that the output torque of the driving motor finally reaches the target torque of the driving motor;

s700, according to the current rotating speed value of the engine and the vehicle speed value, the following operations are carried out:

if the current rotating speed value of the engine is not lower than the manually preset stable engine output rotating speed value and the vehicle speed value is not lower than the manually preset stable engine output vehicle speed value, ending the flow of the idle speed control method;

otherwise, go back to and execute S100 again.

2. The idle speed control method in the hybrid engine starting phase according to claim 1, characterized in that: the value range of the first rotating speed value of the engine is 200 r/min-250 r/min.

3. The idle speed control method in the hybrid engine starting phase according to claim 2, characterized in that: s300 specifically includes the following steps:

s310, comparing the SOC value with an artificially preset SOC lower limit threshold, and according to a comparison result, performing the following operations:

if the SOC value is smaller than the SOC lower limit threshold, setting the automobile to a pure engine mode, and simultaneously setting the engine target torque to be equal to the accelerator torque request value;

otherwise, executing S320;

s320, comparing the accelerator opening value with an manually preset accelerator opening threshold value, and performing the following operations according to a comparison result:

if the accelerator opening value is larger than the accelerator opening threshold value, calculating an automobile output power value according to the accelerator opening value; then the driving engine and the driving motor are output according to the output power value of the automobile;

otherwise, executing S330;

s330, comparing the throttle change rate value with a manually preset throttle change rate threshold value, and performing the following operations according to a comparison result:

if the accelerator change rate value is larger than the accelerator change rate threshold value and the accelerator torque request value is larger than a motor rated torque value of a driving motor, setting the automobile to be in a hybrid mode, simultaneously setting the engine target torque to be equal to an engine high-efficiency torque value, and simultaneously setting the driving motor target torque to be equal to a difference value between the accelerator torque request value and the engine high-efficiency torque value;

otherwise, executing S340;

s340, searching a specification of the driving motor to obtain a rated torque value of the motor; and then comparing the accelerator torque request value with the motor rated torque value, and according to the comparison result, performing the following operations:

when the accelerator torque request value is smaller than the motor rated torque value of the driving motor, setting the automobile to be in a pure electric mode, simultaneously setting the target torque of the engine to be equal to 0, and simultaneously setting the target torque of the driving motor to be equal to the accelerator torque request value;

and when the accelerator torque request value is greater than the motor rated torque value of the driving motor, setting the automobile to be in a hybrid mode, setting the engine target torque to be equal to the difference value between the accelerator torque request value and the motor rated torque value, and setting the driving motor target torque to be equal to the motor rated torque value.

4. The idle speed control method in the hybrid engine starting phase according to claim 3, characterized in that: in S320, the driving motor and the driving motor output according to the output power value of the vehicle, which specifically includes the following steps:

s321, acquiring a current vehicle motion mode, and performing the following operations according to the vehicle motion mode:

if the vehicle motion mode is the economy mode, searching an economy curve in an engine specification to obtain the maximum economy output power; then setting the output power of the engine as the maximum economic output power, and simultaneously setting the output power of the driving motor as the difference value between the output power of the automobile and the maximum economic output power;

setting the engine output power to the vehicle output power if the vehicle motion mode is a power mode.

5. The idle speed control method in the hybrid engine starting phase according to claim 4, characterized in that: the state of charge value is provided by the BMS and is sent to the vehicle control unit through the CAN bus.

6. The idle speed control method in the hybrid engine starting phase according to claim 5, characterized in that: the value range of the charge state lower limit threshold is 0-80%.

7. The idle speed control method in the hybrid engine starting phase according to claim 6, characterized in that: the throttle opening threshold is 80%.

8. The idle speed control method in the hybrid engine starting phase according to claim 7, characterized in that: the value range of the throttle change rate threshold value is 0-20%.

9. The idle speed control method in the hybrid engine starting phase according to claim 8, characterized in that: the engine stable output vehicle speed value is expressed by the following formula:

V₁＝N₁*60*π*D₁/(1000*K₁*K₂)

wherein: v₁Outputting a vehicle speed value for the engine stability; n is a radical of₁Is the first engine speed value; k₁For speed ratio of gearbox, by seeking steamObtaining a vehicle consistency certificate of the vehicle; k₂Obtaining the ratio of the input end to the output end of the transmission system by searching a vehicle consistency certificate of the automobile, wherein the value range is 1-12; d₁The tire diameter is obtained by finding a vehicle conformity certificate of the automobile.

10. The idle speed control method in the hybrid engine starting phase according to claim 9, characterized in that: the value range of the stable output rotating speed value of the engine is 600 r/min-650 r/min.

Technical Field

The invention relates to the technical field of new energy automobiles, in particular to an idle speed control method of a hybrid engine in a starting stage.

Background

The engine needs to be idle controlled during starting. The idling control means that the engine is maintained in operation by idling until the rotation speed of the engine and the vehicle speed of the automobile reach or exceed manually set thresholds. In the state of the automobile, the vehicle speed and the engine speed are relatively low, and the operation of the engine cannot be maintained by means of inertia generated when the automobile runs, but the fuel injection quantity of the engine needs to be strictly controlled to maintain a certain fuel injection quantity to generate a large torque output, so that the self motion state is maintained.

In the prior art, the idling control of the engine adopts PID to adjust the target rotating speed of the engine to realize that the engine is stabilized in an idling working area. Although the prior art of using PID to perform idle speed control is many, the most critical place is to use the engine controller EECU to perform PID regulation of the rotating speed in real time. In short, various parameters fed back in the last time slice are used as input, various different algorithms are adopted, the target rotating speed of the next time slice is calculated, and then the target rotating speed is issued to the EECU for execution.

The PID control is advantageous in that it is accurate because the target rotational speed calculated for each current time slice is determined by the actual operating conditions and vehicle conditions and engine conditions characterized by various parameters in the previous time slice.

But the accuracy of PID control is at the cost of performance; in short, no matter which PID controls the collected parameters and the used algorithm, the parameters and the used algorithm need to be processed in a time-consuming manner; this results in that the target rotation speed adopted by the current time slice corresponds to the previous time slice, but not to the current time slice, and the time difference between the two time slices is the delay of the PID.

PID control, an advanced engine control method, is acceptable for the above-mentioned delay during normal running of the vehicle because the vehicle's own inertia can maintain its moving state; specifically to the engine, i.e., each parameter is generally in smooth transition in two adjacent time slices, it is acceptable to generate the target speed for the current time slice using the parameters of the previous time slice.

But it is not suitable if the PID control method is used in the idle stage. This is because the difficulty of controlling the injection of fuel is very high when the engine is operated in a low speed region. Although the PID is accurate, that time delay may result in an untimely adjustment of the engine speed for low speed regions.

In order to solve this problem, the prior art adopts two sets of ideas: one is to simplify the PID tuning strategy in the idle stage, and the other is to rely on higher computation speed of better processor to process the complex PID tuning strategy.

The simplified PID control method is obviously poor in effect, because the advantage of PID is precise control, and the simplified PID control method is simple and end-to-end.

The high-end equipment is adopted to process a complex PID adjustment strategy, the extra load of the system is inevitably increased, the price of special equipment of the automobile is very high, particularly, the cost of the high-end processor is higher than that of a common processor, the benefit brought by selecting the high-end processor for a short time in the idle stage is not obviously increased, and the cost performance is very low.

On the other hand, the idling stage does not need to accurately control the rotating speed of the engine, and the fundamental reason is that the engine only overcomes the friction resistance of internal parts of the engine in the idling state and does not have the effect on the external output power, namely the working rotating speed range of the engine is only more than the idling speed.

The idle speed control method is characterized in that the idle speed control method is based on a pure engine driven automobile, and has no related technology about a hybrid automobile, and the idle speed control method is simply modified and then transferred to the hybrid automobile, so that the idle speed control method is not suitable for the actual situation of the hybrid automobile.

In summary, the prior art idle speed control has the following drawbacks:

1. because the prior art does not have an idle speed control method of the hybrid electric vehicle, a set of proper coordination strategy of a driving motor and an engine is not provided, and the hybrid electric vehicle can not be well suitable for the actual requirement of the hybrid electric vehicle;

2. due to the time delay of the PID control method, the control difficulty caused by untimely adjustment is increased in a low-speed area, so that the control is inaccurate if the technical scheme is simple, particularly the engine is easy to stall due to too low rotating speed, and high-cost equipment support is required if the technical scheme is complex;

3. after the starter drags the engine to 200(TBD) r/min, the PID adjusts and controls the rotating speed of the engine to an idle speed area, so that the control period is long, the control effect is greatly influenced by PID calibration parameters, and the vehicle is not favorable for rapidly entering a normal driving state;

4. because the rotating speed interval of the engine to the external output power is between the idling speed and the maximum rotating speed, and the hybrid automobile is also provided with the driving motor, but the driving motor does not participate in torque sharing in the prior art, the speed interval from the self-starting of the engine to the idling speed consumes oil and does not output power, and is not economical;

5. the original hybrid vehicle needs to start the vehicle by stepping on the clutch after the engine idles, and the rotating speed of the engine reaches 600r/min and the rotating speed of the motor is 0, so that the clutch is seriously abraded in the transmission combination process of the engine and the motor.

Disclosure of Invention

The invention aims at the problems and provides an idle speed control method for a hybrid engine in a starting stage, which is suitable for hybrid automobiles and coordinates the work coordination of an engine and a driving motor on idle speed control; the idle speed control process in the original PID control process is directly cancelled, and the time delay between two adjacent time slices is greatly shortened; fuel oil is saved; the engine can output power from the beginning of oil injection; and the wear to the clutch during the transmission of the engine and the motor is reduced.

In order to solve the problems, the technical scheme provided by the invention is as follows:

the idle speed control method for the starting stage of the hybrid engine comprises the following steps:

s100, continuously collecting a charge state value, an accelerator opening value, an accelerator torque request value, an accelerator change rate value, a current engine rotating speed value and a vehicle speed value;

s200, starting a starter from the moment of receiving an ignition signal sent by a driver; the method comprises the steps that a starter is used for dragging an engine to rotate until the current rotating speed value of the engine is increased from 0 to a first rotating speed value of the engine, the starter is separated from the engine, and meanwhile the engine starts to inject oil and rotate;

s300, obtaining an engine target torque according to the state of charge value, the accelerator opening value, the accelerator torque request value and the accelerator change rate value;

s400, finding an oil injection quantity value corresponding to the target torque of the engine in an engine torque-oil injection quantity corresponding table preset in an ECU (electronic control Unit); then setting a target fuel injection quantity value equal to the fuel injection quantity value;

s500, searching an engine rotating speed value corresponding to the oil injection quantity value in an engine oil injection quantity-rotating speed corresponding table preset in an ECU (electronic control Unit); then setting an engine execution rotating speed value equal to the engine rotating speed value;

s600, controlling an engine to rotate to enable the current rotating speed value of the engine to reach the execution rotating speed value of the engine; simultaneously controlling the driving motor to rotate, so that the output torque of the driving motor finally reaches the target torque of the driving motor;

s700, according to the current rotating speed value of the engine and the vehicle speed value, the following operations are carried out:

if the current rotating speed value of the engine is not lower than the manually preset stable engine output rotating speed value and the vehicle speed value is not lower than the manually preset stable engine output vehicle speed value, ending the flow of the idle speed control method;

otherwise, go back to and execute S100 again.

Preferably, the first rotating speed value of the engine ranges from 200r/min to 250 r/min.

Preferably, S300 specifically includes the following steps:

s310, comparing the SOC value with an artificially preset SOC lower limit threshold, and according to a comparison result, performing the following operations:

if the SOC value is smaller than the SOC lower limit threshold, setting the automobile to a pure engine mode, and simultaneously setting the engine target torque to be equal to the accelerator torque request value;

otherwise, executing S320;

s320, comparing the accelerator opening value with an manually preset accelerator opening threshold value, and performing the following operations according to a comparison result:

if the accelerator opening value is larger than the accelerator opening threshold value, calculating an automobile output power value according to the accelerator opening value; then the driving engine and the driving motor are output according to the output power value of the automobile;

otherwise, executing S330;

s330, comparing the throttle change rate value with a manually preset throttle change rate threshold value, and performing the following operations according to a comparison result:

if the accelerator change rate value is larger than the accelerator change rate threshold value and the accelerator torque request value is larger than a motor rated torque value of a driving motor, setting the automobile to be in a hybrid mode, simultaneously setting the engine target torque to be equal to an engine high-efficiency torque value, and simultaneously setting the driving motor target torque to be equal to a difference value between the accelerator torque request value and the engine high-efficiency torque value;

otherwise, executing S340;

s340, searching a specification of the driving motor to obtain a rated torque value of the motor; and then comparing the accelerator torque request value with the motor rated torque value, and according to the comparison result, performing the following operations:

when the accelerator torque request value is smaller than the motor rated torque value of the driving motor, setting the automobile to be in a pure electric mode, simultaneously setting the target torque of the engine to be equal to 0, and simultaneously setting the target torque of the driving motor to be equal to the accelerator torque request value;

and when the accelerator torque request value is greater than the motor rated torque value of the driving motor, setting the automobile to be in a hybrid mode, setting the engine target torque to be equal to the difference value between the accelerator torque request value and the motor rated torque value, and setting the driving motor target torque to be equal to the motor rated torque value.

Preferably, the step S320 of outputting the driving motor and the driving motor according to the output power value of the vehicle specifically includes the following steps:

s321, acquiring a current vehicle motion mode, and performing the following operations according to the vehicle motion mode:

if the vehicle motion mode is the economy mode, searching an economy curve in an engine specification to obtain the maximum economy output power; then setting the output power of the engine as the maximum economic output power, and simultaneously setting the output power of the driving motor as the difference value between the output power of the automobile and the maximum economic output power;

setting the engine output power to the vehicle output power if the vehicle motion mode is a power mode.

Preferably, the state of charge value is provided by the BMS and transmitted to the vehicle control unit via the CAN bus.

Preferably, the value range of the state of charge lower limit threshold is 0-80%.

Preferably, the accelerator opening threshold is 80%.

Preferably, the throttle change rate threshold value is in a range of 0-20%.

Preferably, the engine steady output vehicle speed value is expressed by:

V₁＝N₁*60*π*D₁/(1000*K₁*K₂)

wherein: v₁Outputting a vehicle speed value for the engine stability; n is a radical of₁Is the first engine speed value; k₁Obtaining the speed ratio of the gearbox by searching a vehicle consistency certificate of the automobile; k₂Obtaining the ratio of the input end to the output end of the transmission system by searching a vehicle consistency certificate of the automobile, wherein the value range is 1-12; d₁The tire diameter is obtained by finding a vehicle conformity certificate of the automobile.

Preferably, the value range of the stable output rotating speed value of the engine is 600 r/min-650 r/min.

Compared with the prior art, the invention has the following advantages:

1. the invention is a technical scheme which is specially designed for a hybrid automobile and is used for finishing idle speed control by an engine and a driving motor together, so that the working coordination of the engine and the driving motor on the idle speed control can be well coordinated, and the hybrid automobile idle speed control system is more suitable for a special platform of the hybrid automobile than the prior art;

2. because the invention does not adopt a PID control method, but adopts the table lookup to obtain data, the idle speed control process in the original PID control process is directly cancelled, thereby greatly shortening the time delay between two adjacent time slices, realizing accurate control and not needing to adopt high-cost equipment;

3. in the process from 200(TBD) r/min to idle speed, the engine injects oil and outputs power, so that the vehicle can be directly driven to advance at the stage, and compared with the prior art, the invention saves a large amount of fuel oil and is very economical;

4. because the driving motor is adopted to drag the engine to rotate in a mode of combining the clutch, the internal friction resistance of the engine is overcome, so that the effective working rotating speed range of the engine is expanded to be more than the starting rotating speed of the engine, the engine can output power from the beginning of oil injection, and meanwhile, the problem that the power can be output externally only after the engine is more than the idle speed in the prior art is solved;

5. after the idle speed is cancelled, the clutch can be stepped to start when the rotating speed of the engine reaches the ignition position of 200r/min, so that the abrasion of the clutch during the transmission of the engine and the motor is greatly reduced.

Drawings

FIG. 1 is a schematic flow chart of a control method according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of an engine torque-fuel injection curve selection for a DCI420 engine according to an embodiment of the present invention;

FIG. 3 is an illustration of an engine fuel injection-speed curve selection of a DCI420 engine according to an embodiment of the present invention;

FIG. 4 is a schematic illustration of an alternate speed-output power curve of a DCI420 engine as a pure fuel engine according to an embodiment of the present invention;

fig. 5 is a schematic diagram of the rotation speed-output power curve selection of a DCI420 engine and a driving motor matched to form a hybrid engine according to an embodiment of the present invention.

Detailed Description

The present invention is further illustrated by the following examples, which are intended to be purely exemplary and are not intended to limit the scope of the invention, as various equivalent modifications of the invention will occur to those skilled in the art upon reading the present disclosure and fall within the scope of the appended claims.

It should be noted that the present embodiment is described based on the DCI420 engine to better help the skilled person understand the principle and the using method of the present invention.

It should be further noted that the hybrid automobile component according to the present embodiment includes: the system comprises an accelerator pedal, a brake pedal, a vehicle control unit (HCU), a driving Motor Controller (MCU), an engine controller (EECU), a clutch, a gearbox and wheels; the two power units of the driving motor and the engine belong to a power system together.

It should be further noted that all the places related to the "engine" in the present invention refer to the fuel engine; on the other hand, the drive motor of the hybrid vehicle is referred to wherever the "drive motor" is concerned. The fuel oil engine and the driving motor jointly form a power system of the hybrid electric vehicle.

Hybrid vehicles have three modes of motion: pure electric mode, i.e. all power comes from the driving motor; engine only mode, with all power from the engine; in the hybrid mode, the engine and the drive motor each share a portion of the power requirements of the vehicle.

As shown in fig. 1, the idle speed control method in the starting stage of the hybrid engine comprises the following steps:

s100, continuously collecting a charge state value, an accelerator opening value, an accelerator torque request value, an accelerator change rate value, a current engine rotating speed value and a vehicle speed value.

S200, starting a starter from the moment when the HCU receives an ignition signal sent by a driver; the starter pulls the engine to rotate until the current rotating speed value of the engine is increased from 0 to a first rotating speed value of the engine, the starter is separated from the engine, and the engine starts to inject oil to rotate; at this time, the operation of the starter is finished, and the process of the invention is exited.

In this embodiment, the first engine speed value N₁The value range of (A) is 200 r/min-250 r/min.

It should be noted that the engine of the hybrid vehicle is stationary until the driver ignites, and the engine is then pulled by the starter to a speed N₁(ii) a At the moment of receiving the ignition signal and all the previous moments, the engine is in a static state, namely the current rotating speed and the fuel injection quantity of the engine are both 0; when the ignition signal is received, a starter is started firstly, and the starter drives the engine to rotate; in the process, the ignition condition of the engine cannot be triggered due to the fact that the rotating speed is too low at the beginning, the engine is in an un-started state at the moment theoretically, the oil injection quantity is 0, and the engine runs along with the starter; when the rotating speed is higher and higher, the first rotating speed value N of the engine is reached₁When the ignition condition of the engine is triggered, the engine can be ignited and started, the fuel injection quantity is greater than 0, and meanwhile, the starter is disconnected and stops working without dragging the engine; in the next stage, the engine is required to do work by itself to overcome the internal friction until the rotating speed is stabilized at the stable output rotating speed value of the engine, thereby finishing the operationAnd controlling the idle speed.

It is further noted that for different types of engines, according to the design requirements of the engine, N₁The value difference is large, the range is allowed from 200r/min to 1000r/min, and a specific value can be determined in a relatively narrow range only by carrying out a large number of experiments, tests and analyses on a specific engine. On the other hand once N of an engine₁If the engine type is determined, the method can be applied to all engines of the type, and the method is written into a vehicle control unit HCU and an engine controller EECU in a manual preset mode.

S300, obtaining a target torque of the engine according to the state of charge value, the accelerator opening value, the accelerator torque request value and the accelerator change rate value; s300 specifically includes the following steps:

s310, comparing the state of charge value with an artificially preset state of charge lower limit threshold, and performing the following operations according to the comparison result:

and if the SOC value is smaller than the SOC lower limit threshold, setting the automobile to a pure engine mode, and simultaneously setting the engine target torque to be equal to the accelerator torque request value.

Otherwise, S320 is performed.

In this embodiment, the state of charge value is provided by the BMS and sent to the vehicle controller via the CAN bus.

In this embodiment, the value of the lower threshold of the state of charge is 0-80%.

It should be further noted that, in this embodiment, the lower threshold of the state of charge is set to 20%, or 50%; specifically, 20% or 50% or other values are used, and control strategies for dynamic performance and economic performance in application scenarios are comprehensively considered.

It should be further explained that, firstly, it is determined whether the state of charge value is lower than the state of charge lower limit threshold value because it is determined whether the battery is in a power shortage state; the battery under the power shortage can not support the action of the driving motor for a long time and needs to be charged; the charged electric energy comes from the output power of the engine; the engine can only provide all power at this time, and the battery is charged at the same time; this is why S310 needs to be set to the engine-only mode if a power shortage is found; from S320 below, the battery may provide power, and the engine may charge the battery in real time if it participates in the operation.

S320, comparing the accelerator opening value with an manually preset accelerator opening threshold, and performing the following operations according to the comparison result:

if the accelerator opening value is larger than the accelerator opening threshold value, calculating the output power value of the automobile according to the accelerator opening value; and then the driving engine and the driving motor are output according to the output power value of the automobile.

Otherwise, S330 is performed.

In this embodiment, the accelerator opening threshold is 80%.

In this step, the driving motor and the driving motor are output according to the output power value of the automobile, which specifically comprises the following steps:

s321, acquiring a current vehicle motion mode, and performing the following operations according to the vehicle motion mode:

if the vehicle motion mode is the economy mode, searching an economy curve in an engine specification to obtain the maximum economy output power; and then setting the output power of the engine as the maximum economic output power, and simultaneously setting the output power of the driving motor as the difference value of the output power of the automobile and the maximum economic output power.

If the vehicle motion mode is the power mode, the engine output power is set as the vehicle output power.

S330, comparing the throttle change rate value with a manually preset throttle change rate threshold value, and performing the following operations according to the comparison result:

and if the accelerator change rate value is larger than the accelerator change rate threshold value and the accelerator torque request value is larger than the motor rated torque value of the driving motor, setting the automobile in a hybrid mode, simultaneously setting the engine target torque to be equal to the engine high-efficiency torque value, and simultaneously setting the driving motor target torque to be equal to the difference value between the accelerator torque request value and the engine high-efficiency torque value.

Otherwise, S340 is performed.

In the specific embodiment, the value range of the throttle change rate threshold is 0-20%.

It should be further noted that the threshold throttle change rate is set to 5% in this embodiment.

S340, searching a specification of the driving motor to obtain a rated torque value of the motor; then comparing the accelerator torque request value with the motor rated torque value, and according to the comparison result, performing the following operations:

and when the accelerator torque request value is smaller than the motor rated torque value of the driving motor, setting the automobile to be in a pure electric mode, simultaneously setting the target torque of the engine to be equal to 0, and simultaneously setting the target torque of the driving motor to be equal to the accelerator torque request value.

When the accelerator torque request value is larger than the motor rated torque value of the driving motor, the automobile is set to be in a hybrid mode, meanwhile, the engine target torque is set to be equal to the difference value of the accelerator torque request value and the motor rated torque value, and meanwhile, the driving motor target torque is set to be equal to the motor rated torque value.

It should be noted that the whole S300, including the sub-step of S300, functions to distribute the corresponding engine target torque and the driving motor target torque to the driving motor and the engine through the whole vehicle controller HCU. Which is one of the most basic parameters required by the present invention.

In the embodiment, the requested value of the accelerator torque ranges from 1000N · m to 4000N · m.

It should be further noted that the requested throttle torque value is set to 2500 in this embodiment.

S400, after an engine controller EECU receives an engine target torque sent by a vehicle control unit HCU, searching an oil injection quantity value corresponding to the engine target torque in an engine torque-oil injection quantity corresponding table preset in an ECU manually; then setting the target oil injection quantity value equal to the oil injection quantity value; the engine torque-fuel injection quantity correspondence table of the DCI420 engine is shown in table 1:

TABLE 1 DCI420 Engine Torque-fuel injection quantity correspondence table (optional)

Target engine torque N m	1500	1700	2000	1900	1800	1700	1600	1500	1000
										Fuel injection quantity mg	150	200	220	218	216	215	214	210	206

It should be noted that table 1 is an option of a DCI420 engine torque-fuel injection quantity correspondence table; the data in the engine torque-fuel injection quantity corresponding table is calibrated through experiments, the characteristic points are extremely many, and only a few integral torques are taken as display; the characteristic point is a point under a two-dimensional coordinate system formed by a pair of engine target torques and corresponding fuel injection quantities; for the engine torque-fuel injection quantity corresponding table, the more the characteristic points are, the more accurate the numerical value is, the more accurate the numerical value can be adapted to the engine of the current model, the idle speed adjusting process of the engine without output of oil is avoided, and the oil consumption and vibration of the engine are reduced.

As shown in fig. 2, which is an engine torque-fuel injection curve of the DCI420 engine, it is obvious that this is a continuous and smooth curve, and contains many characteristic points.

In the embodiment, the value range of the oil injection quantity value is 0 mg-300 mg.

It should be further noted that the term "idle speed regulation process" refers to regulating the current engine speed from N₁And reaching the stage of stable output speed value of the engine.

It needs to be further explained that if the working condition at this time is hill start, the power can be output already when the current rotating speed value of the engine is higher than 200r/min, and the power is output by superposition with the power of the driving motor; and need the independent output power of driving motor before accomplishing the process of idle speed regulation, consequently, this patent can make whole car select for use the driving motor of smaller model, and it considers that the weight that lies in driving motor is lighter and the price is lower, can satisfy the start needs of this model of motorcycle.

S500, after the engine controller EECU looks up a table to obtain an oil injection quantity value, further looking up the engine rotating speed corresponding to the oil injection quantity value in an engine oil injection quantity-rotating speed corresponding table preset in an ECU manually; then setting the engine execution rotating speed value to be equal to the engine rotating speed; the engine fuel injection quantity-rotating speed correspondence table of the DCI420 engine is shown in the table 2:

TABLE 2 DCI420 Engine Fuel injection-speed map (250 kPa or more) (optional)

Engine speed r/min	800	930	1000	1100	1200	1270	1300	1400	1500	1600
											Fuel injection quantity mg	155	205	219	218	216	215	214	212	211	205

Note that the number of the characteristic points in table 2 is the same as that in table 1, and the characteristic points in table 2 are associated with table 1 in accordance with the value of the fuel injection amount.

As shown in fig. 3, it is an engine fuel injection-speed curve of the DCI420 engine, and it is obvious that this is also a continuous and smooth curve, and the number of characteristic points included is also very large.

It should be further noted that, although tables 1 and 2 both contain a large number of accurate values obtained through experiments, in practical applications, the situation that the fuel injection amount performed by the engine does not correspond to that of table 1 may still be met, and in this case, the rounding process may be adopted.

S600, controlling the engine to rotate by the engine controller EECU according to the engine execution rotating speed value obtained by looking up a table, so that the current rotating speed value of the engine reaches the engine execution rotating speed value; and meanwhile, the driving motor is controlled to rotate, so that the output torque of the driving motor finally reaches the target torque of the driving motor.

S700, according to the current rotating speed value and the vehicle speed value of the engine, the following operations are carried out:

if the current rotating speed value of the engine is not lower than the manually preset stable engine output rotating speed value and the vehicle speed value is not lower than the manually preset stable engine output vehicle speed value, the flow of the idle speed control method is ended.

Otherwise, go back to and execute S100 again.

It should be noted that the value of the engine steady output speed, i.e. the so-called idle speed, is also determined according to the design characteristics of the specific engine model, and the parameter values are consistent for the same engine model.

In this embodiment, the engine steady output vehicle speed value is expressed by equation (1):

V₁＝N₁*60*π*D₁/(1000*K₁*K₂) (1)

wherein: v₁Outputting a vehicle speed value for the engine stability; n is a radical of₁Is a first engine speed value; k₁Obtaining the speed ratio of the gearbox by searching a vehicle consistency certificate of the automobile; k₂For the ratio of input to output of the transmission system, by looking upFinding a vehicle consistency certificate of the automobile to obtain the vehicle consistency certificate, wherein the value range is 1-12; d₁The tire diameter is obtained by finding a vehicle conformity certificate of the automobile.

It is further noted that the stable output rotating speed value of the engine ranges from 600r/min to 650 r/min.

It should be further noted that the vehicle consistency certificate is an important parameter basis to be referred by a vehicle model engineer when designing a new vehicle, and the vehicle model engineer searches for an inherent parameter of the vehicle consistency certificate of the vehicle according to vehicle components such as a gearbox, a rear axle and the like of a selected specific model.

For example, if the vehicle engineer selects a transmission matched with the DCI420 engine of the hybrid vehicle of the embodiment as a green-control 5-gear transmission, the vehicle consistency certificate of the vehicle is searched for: k of each gear₁The values are in turn 6.62/3.73/2.3/1.51/1/0.75/6.04R (reverse).

In this embodiment K₂The setting is 5.28, and the value range of 1-12 is met.

In order to better show the effect of the invention, the rotating speed and the output power of the DCI420 engine serving as a pure fuel engine and the DCI420 engine matched with a driving motor under two working conditions of being a hybrid engine are compared as follows:

as shown in table 3, the engine speed-output power correspondence table is shown when the DCI420 engine is used as a pure fuel engine;

it should be noted that, since the DCI420 engine is a well-developed engine, and is especially adopted by reynolds and standard series vehicles, the data in table 3 is real vehicle real data.

TABLE 3 DCI420 Engine speed-output Power correspondence table (pure fuel engine, selected)

FIG. 4 is a schematic diagram illustrating the rotation speed-output power curve of a DCI420 engine as a pure fuel engine.

As shown in tables 4.1-4.3, the engine speed-output power corresponding table is shown when the DCI420 engine and the driving motor are matched to form a hybrid engine;

it should be noted that, for the mixed working condition, the data collected by the simulation of the CRUISE model is adopted.

TABLE 4.1 DCI420 Engine speed-output Power correspondence table (hybrid engine, alternate)

TABLE 4.2 DCI420 Engine speed-output Power corresponding table (hybrid engine, alternate)

TABLE 4.3 DCI420 Engine speed-output Power correspondence table (hybrid engine, alternate)

Fig. 5 is a schematic diagram illustrating the rotation speed-output power curve selection of a DCI420 engine and a driving motor in cooperation to form a hybrid engine.

In the foregoing detailed description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the subject matter require more features than are expressly recited in each claim. Rather, as the following claims reflect, invention lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. To those skilled in the art; various modifications to these embodiments will be readily apparent, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term "comprising" as "comprising" is interpreted when employed as a transitional word in a claim. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or".

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Finally, it should be noted that the above embodiments are merely representative examples of the present invention. It is obvious that the invention is not limited to the above-described embodiments, but that many variations are possible. Any simple modification, equivalent change and modification made to the above embodiments in accordance with the technical spirit of the present invention should be considered to be within the scope of the present invention.

Here, it should be noted that the description of the above technical solutions is exemplary, the present specification may be embodied in different forms, and should not be construed as being limited to the technical solutions set forth herein. Rather, these descriptions are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Furthermore, the technical solution of the present invention is limited only by the scope of the claims.

The shapes, sizes, ratios, angles, and numbers disclosed to describe aspects of the specification and claims are examples only, and thus, the specification and claims are not limited to the details shown. In the following description, when a detailed description of related known functions or configurations is determined to unnecessarily obscure the focus of the present specification and claims, the detailed description will be omitted.

Where the terms "comprising", "having" and "including" are used in this specification, there may be another part or parts unless otherwise stated, and the terms used may generally be in the singular but may also be in the plural.

It should be noted that although the terms "first," "second," "top," "bottom," "side," "other," "end," "other end," and the like may be used and used in this specification to describe various components, these components and parts should not be limited by these terms. These terms are only used to distinguish one element or section from another element or section. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, with the top and bottom elements being interchangeable or switchable with one another, where appropriate, without departing from the scope of the present description; the components at one end and the other end may be of the same or different properties to each other.

Further, in constituting the component, although it is not explicitly described, it is understood that a certain error region is necessarily included.

In describing positional relationships, for example, when positional sequences are described as being "on.. above", "over.. below", "below", and "next", unless such words or terms are used as "exactly" or "directly", they may include cases where there is no contact or contact therebetween. If a first element is referred to as being "on" a second element, that does not mean that the first element must be above the second element in the figures. The upper and lower portions of the member will change depending on the angle of view and the change in orientation. Thus, in the drawings or in actual construction, if a first element is referred to as being "on" a second element, it can be said that the first element is "under" the second element and the first element is "over" the second element. In describing temporal relationships, unless "exactly" or "directly" is used, the description of "after", "subsequently", and "before" may include instances where there is no discontinuity between steps. The features of the various embodiments of the present invention may be partially or fully combined or spliced with each other and performed in a variety of different configurations as would be well understood by those skilled in the art. Embodiments of the invention may be performed independently of each other or may be performed together in an interdependent relationship.