阅读说明：本技术 混合动力汽车发动机起停时机的控制方法 (Control method for start-stop time of engine of hybrid electric vehicle ) 是由 张鹏 宋辉 邢兆林 张天锷 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种混合动力汽车发动机起停时机的控制方法,包括：整车上强电后,整车处于D档；针对各车速段的发动机起停时机判断条件,实施分段控制；整车控制器接收到充电请求标志位时,根据车速判断是否起动发动机；整车控制器接收到强制充电请求标志位时,起动发动机给动力电池充电。本发明的混合动力汽车发动机起停时机的控制方法,可以合理控制发动机起停时机,进而控制SOC使用区间,可有效改善整车燃油经济性和发动机频繁起停导致的驾驶平顺性问题,可以提高混合动力汽车的燃油经济性和驾驶舒适性。(The invention discloses a control method for start-stop time of an engine of a hybrid electric vehicle, which comprises the following steps: after the whole vehicle is electrified with strong electricity, the whole vehicle is in a D gear; implementing sectional control according to the engine start-stop time judgment condition of each vehicle speed section; when the vehicle control unit receives the charging request flag bit, judging whether to start the engine according to the vehicle speed; and when the vehicle control unit receives the forced charging request flag bit, starting the engine to charge the power battery. The control method of the start-stop time of the engine of the hybrid electric vehicle can reasonably control the start-stop time of the engine, further control the SOC use interval, effectively improve the fuel economy of the whole vehicle and the driving smoothness problem caused by frequent start-stop of the engine, and improve the fuel economy and the driving comfort of the hybrid electric vehicle.)

1. A method for controlling start and stop timing of an engine of a hybrid vehicle, comprising:

after the whole vehicle is electrified with strong electricity, the whole vehicle is in a D gear;

implementing sectional control according to the engine start-stop time judgment condition of each vehicle speed section;

when the vehicle control unit receives the charging request flag bit, judging whether to start the engine according to the vehicle speed;

and when the vehicle control unit receives the forced charging request flag bit, starting the engine to charge the power battery.

2. The method of controlling start and stop timing of an engine of a hybrid vehicle according to claim 1, wherein it is determined whether to start the engine based on the first condition when the vehicle speed reaches a first set value.

3. The method for controlling the start-stop timing of the engine of the hybrid vehicle according to claim 2, wherein the first set value is in a range of 0 to 70kph, and the first condition includes that the SOC of the power battery reaches a set value, the opening degree of the accelerator pedal reaches a set value, and the temperature of the engine water reaches a set value; when the SOC of the power battery, the opening degree of an accelerator pedal or the water temperature of the engine reaches a set value, the engine is started immediately.

4. The method for controlling the start-stop timing of the engine of the hybrid vehicle according to claim 3, wherein the engine is started immediately when the vehicle speed reaches a first set value and the SOC of the power battery is less than 20%; when the vehicle speed reaches a first set value and the opening degree of an accelerator pedal is greater than 95%, starting the engine immediately; when the vehicle speed reaches a first set value and the water temperature of the engine is lower than 60 ℃, the engine is started immediately.

5. The method for controlling the start-stop timing of the engine of the hybrid electric vehicle according to any one of claims 2 to 4, wherein the engine is started to charge the power battery when the vehicle speed is greater than 10kph, the SOC of the power battery is in the range of 20% -30%, and the temperature of the engine water is higher than 60 ℃.

6. The method for controlling the start-stop time of the engine of the hybrid electric vehicle according to any one of claims 2 to 4, wherein when the vehicle speed is greater than 10kph, the SOC of the power battery is greater than 30%, the opening degree of an accelerator pedal is greater than 95%, and the temperature of the engine water is greater than 60 ℃, whether to start the engine is determined according to the power requirement of the whole vehicle.

7. The method of controlling the start-stop timing of the engine of the hybrid vehicle according to any one of claims 2 to 6, wherein the engine is forcibly started when the vehicle speed is greater than the second set value, and the hybrid vehicle is operated in a hybrid mode without allowing the engine to stall.

8. The method for controlling the start-stop opportunity of the engine of the hybrid electric vehicle as claimed in any one of claims 1 to 7, wherein when the vehicle control unit receives the charging request flag bit, if the vehicle speed is greater than 10kph, the engine is started immediately to charge the power battery, and after the SOC of the power battery is greater than 43%, the engine is allowed to shut down; and if the vehicle speed is less than 10kph, controlling the engine to stop.

9. The method for controlling the start-stop timing of the engine of the hybrid electric vehicle as claimed in any one of claims 1 to 7, wherein when the vehicle control unit receives the forced charging request flag bit, the engine is started to charge the power battery until the SOC of the power battery is greater than 43%, and the engine is allowed to stop.

10. The method for controlling the start-stop timing of the engine of the hybrid vehicle according to any one of claims 1 to 7, wherein if the vehicle control unit receives the forced charging request flag bit, the engine water temperature is less than 60 ℃ or the accelerator pedal opening is greater than 95%, the engine is allowed to be started at a vehicle speed of less than 10 kph.

Technical Field

The invention belongs to the technical field of hybrid electric vehicles, and particularly relates to a control method for start-stop time of an engine of a hybrid electric vehicle.

Background

Usable driving motor of hybrid vehicle or engine are as the power supply, compare in can only rely on the engine as the traditional car of power supply, in the aspect of the driving experience, the motor has characteristics such as the moment of torsion response is fast, quiet for the engine, can greatly promote driver's driving enjoyment, and simultaneously, the energy saving has, reduce and discharge the pollution, advantages such as environmental protection more, at the oil consumption, it is strict that emission policy and regulation day, green is at the moment of the imperative, hybrid vehicle becomes the new trend of automobile industry technological development.

The intervention time of the engine in the driving cycle working condition and the working point of the engine have great influence on the economy and driving smoothness of the whole system. The engine of the existing hybrid electric vehicle is not suitable in intervention time, so that the problems that the whole vehicle shakes when the vehicle starts and stops, the engine cannot work in a high-efficiency area and the like can be caused, the energy-saving and emission-reducing effects of the hybrid electric vehicle can be reduced, and the driving comfort can be reduced.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a control method for start-stop time of an engine of a hybrid electric vehicle, aiming at improving the fuel economy and driving comfort of the hybrid electric vehicle.

In order to achieve the purpose, the invention adopts the technical scheme that: the control method of the start-stop time of the engine of the hybrid electric vehicle comprises the following steps:

after the whole vehicle is electrified with strong electricity, the whole vehicle is in a D gear;

implementing sectional control according to the engine start-stop time judgment condition of each vehicle speed section;

when the vehicle control unit receives the charging request flag bit, judging whether to start the engine according to the vehicle speed;

and when the vehicle control unit receives the forced charging request flag bit, starting the engine to charge the power battery.

When the vehicle speed reaches a first set value, whether to start the engine is judged according to a first condition.

The first set value is in the range of 0-70kph, and the first condition comprises that the SOC of the power battery reaches the set value, the opening degree of an accelerator pedal reaches the set value and the water temperature of the engine reaches the set value; when the SOC of the power battery, the opening degree of an accelerator pedal or the water temperature of the engine reaches a set value, the engine is started immediately.

When the vehicle speed reaches a first set value and the SOC of the power battery is less than 20%, the engine is started immediately; when the vehicle speed reaches a first set value and the opening degree of an accelerator pedal is greater than 95%, starting the engine immediately; when the vehicle speed reaches a first set value and the water temperature of the engine is lower than 60 ℃, the engine is started immediately.

When the vehicle speed is more than 10kph, the SOC of the power battery is in the range of 20% -30% and the water temperature of the engine is higher than 60 ℃, the engine is started to charge the power battery.

When the vehicle speed is more than 10kph, the SOC of the power battery is more than 30%, the opening of an accelerator pedal is more than 95%, and the water temperature of the engine is higher than 60 ℃, whether the engine is started is determined according to the power requirement of the whole vehicle.

When the speed of the vehicle is greater than the second set value, the engine is forcibly started, and the hybrid electric vehicle runs in a hybrid mode without allowing the engine to stall.

When the vehicle control unit receives the charging request flag bit, if the vehicle speed is greater than 10kph, the engine is started immediately to charge the power battery, and the engine is allowed to shut down after the SOC of the power battery is greater than 43%; and if the vehicle speed is less than 10kph, controlling the engine to stop.

When the vehicle control unit receives the forced charging request flag bit, the engine is started to charge the power battery until the SOC of the power battery is more than 43%, and the engine is allowed to shut down.

And if the vehicle control unit receives the forced charging request flag bit, the water temperature of the engine is less than 60 ℃ or the opening degree of an accelerator pedal is greater than 95%, the engine is allowed to be started when the vehicle speed is less than 10 kph.

The control method of the start-stop time of the engine of the hybrid electric vehicle can reasonably control the start-stop time of the engine, further control the SOC use interval, effectively improve the fuel economy of the whole vehicle and the driving smoothness problem caused by frequent start-stop of the engine, and improve the fuel economy and the driving comfort of the hybrid electric vehicle.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a flow chart of a method of controlling engine start-stop timing of a hybrid vehicle according to the present invention;

FIG. 2 is a schematic structural diagram of a hybrid transmission;

labeled as: 1. a housing; 2. a drive motor; 3. an ISG motor; 4. a first shaft; 5. a second shaft; 6. a third axis; 7. a fourth axis; 8. a first sun gear; 9. a second sun gear; 10. a first planetary gear; 11. a second planetary gear; 12. a torsional vibration damper; 13. a planet carrier; 14. a fifth shaft; 15. a first reduction gear; 16. a second reduction gear; 17. a third reduction gear; 18. a fourth reduction gear; 19. a fifth reduction gear; 20. a sixth reduction gear; 21. a differential assembly; 22. and a half shaft.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings for a purpose of helping those skilled in the art to more fully, accurately and deeply understand the concept and technical solution of the present invention and to facilitate its implementation.

It should be noted that, in the following embodiments, the terms "first", "second" and "third" do not denote absolute differences in structure and/or function, nor do they denote a sequential order of execution, but rather are used for convenience of description.

As shown in FIG. 1, the invention provides a control method for start-stop time of an engine of a hybrid electric vehicle, which comprises the following steps:

after the whole vehicle is electrified with strong electricity, the whole vehicle is in a D gear;

implementing sectional control according to the engine start-stop time judgment condition of each vehicle speed section;

when the vehicle control unit receives the charging request flag bit, judging whether to start the engine according to the vehicle speed;

and when the vehicle control unit receives the forced charging request flag bit, starting the engine to charge the power battery.

As shown in fig. 2, the hybrid transmission of the hybrid vehicle includes a housing 1, a driving motor 2, an ISG motor 3, a differential assembly 21, a first shaft 4, a second shaft 5, a third shaft 6, a fourth shaft 7, a stepped planetary gear set and a power transmission mechanism, wherein the driving motor 2, the ISG motor 3, the differential assembly 21, the first shaft 4, the second shaft 5, the third shaft 6, the fourth shaft 7, the stepped planetary gear set and the power transmission mechanism are disposed inside the housing 1. The stepped planetary gear set comprises a first sun gear 8, a second sun gear 9, a first planetary gear 10, a second planetary gear 11 and a planet carrier 13, wherein the first sun gear 8 and the second sun gear 9 are coaxially arranged, the first planetary gear 10 and the second planetary gear 11 are arranged in a plurality, the number of the first planetary gear 10 and the number of the second planetary gear 11 are the same, and each first planetary gear 10 is coaxially and fixedly connected with one second planetary gear 11. The first sun gear 8 meshes with first planetary gears 10, the second sun gear 9 meshes with second planetary gears 11, and the first planetary gears 10 and the second planetary gears 11 are rotatably provided on a carrier 13. The first sun gear 8 is connected with the first shaft 4, the first shaft 4 is connected with the ISG motor 3, the second sun gear 9 is connected with the second shaft 5, the second shaft 5 is connected with the torsional vibration damper 12, the engine is connected with the torsional vibration damper 12, and the first shaft 4 and the second shaft 5 are coaxially arranged. The driving motor 2 and the ISG motor 3 are coaxially arranged, the stepped planetary gear set is positioned between the driving motor 2 and the torsional damper 12, and the driving motor 2 is positioned between the stepped planetary gear set and the ISG motor 3. The power transmission mechanism comprises a third shaft 6 connected with a planet carrier 13, a first reduction gear 15 connected with the third shaft 6, a second reduction gear 16 meshed with the first reduction gear 15, a fourth shaft 7 connected with the driving motor 2, a third reduction gear 17 connected with the fourth shaft 7, a fourth reduction gear 18 meshed with the third reduction gear 17, a fifth reduction gear 19 arranged on the fifth shaft 14 and a sixth reduction gear 20 meshed with the fifth reduction gear 19, wherein the sixth reduction gear 20 is arranged on a differential assembly 21. The fifth shaft 14 is parallel to the first shaft 4, the second reduction gear 16, the fourth reduction gear 18 and the fifth reduction gear 19 are fixedly arranged on the fifth shaft 14, the sixth reduction gear 20 is fixedly connected with the differential assembly 21, the diameter of the fifth reduction gear 19 is smaller than that of the sixth reduction gear 20, and the fifth reduction gear 19 is positioned between the second reduction gear 16 and the fourth reduction gear 18.

As shown in fig. 2, the third shaft 6 and the fourth shaft 7 are hollow shafts, the third shaft 6 is sleeved on the second shaft 5, the second shaft 5 and the third shaft 6 are coaxially arranged, the fourth shaft 7 is sleeved on the first shaft 4, the fourth shaft 7 and the first shaft 4 are coaxially arranged, and the stepped planetary gear set is located between the first reduction gear 15 and the third reduction gear 17.

The method for controlling the start-stop time comprises the following steps:

1. after the whole vehicle is powered by strong electricity, the whole vehicle is in a D gear, whether the engine is started or not is comprehensively judged according to the water temperature of the engine, the residual electricity quantity (SOC) of a power battery, the opening degree of an accelerator pedal and the vehicle speed by combining a charging request flag bit (SOC is less than 30%) and a forced charging request flag bit (SOC is less than 20%) set according to the SOC of the power battery, the driving working condition is divided into a low-speed section, a medium-speed section (the vehicle speed is 0-70kph) and a high-speed section (the vehicle speed is more than 70kph), the priority of the forced charging flag bit is highest, and the forced starting engine is charged for the power battery under any condition.

As shown in fig. 1, when the vehicle speed reaches a first set value, it is determined whether to start the engine according to a first condition. The first set value is in the range of 0-70kph, and the first condition comprises that the SOC of the power battery reaches the set value, the opening degree of an accelerator pedal reaches the set value and the water temperature of the engine reaches the set value; when the SOC of the power battery, the opening degree of an accelerator pedal or the water temperature of the engine reaches a set value, the engine is started immediately.

2. And implementing sectional control according to the judgment condition of the start-stop time of the engine in each vehicle speed section.

When the vehicle speed reaches a first set value and the SOC of the power battery is less than 20%, the engine is started immediately; when the vehicle speed reaches a first set value and the opening degree of an accelerator pedal is greater than 95%, starting the engine immediately; when the vehicle speed reaches a first set value and the water temperature of the engine is lower than 60 ℃, the engine is started immediately.

When the vehicle speed is more than 10kph, the SOC of the power battery is in the range of 20% -30% and the water temperature of the engine is higher than 60 ℃, the engine is started to charge the power battery.

When the vehicle speed is more than 10kph, the SOC of the power battery is more than 30%, the opening of an accelerator pedal is more than 95%, and the water temperature of the engine is higher than 60 ℃, whether the engine is started is determined according to the power requirement of the whole vehicle.

Thus, as shown in FIG. 2, at vehicle speeds less than 0-70kph, the engine start-stop timing control logic is:

1) after high-voltage electrification, when any condition that the SOC of the power battery is less than 20 percent, the opening degree of an accelerator pedal is more than 95 percent or the water temperature of the engine is lower than 60 ℃ is met, the engine is started immediately;

2) and when the SOC of the power battery is more than 20%, the opening degree of an accelerator pedal is less than 95%, and the water temperature of the engine is higher than 60 ℃, the vehicle speed is more than 10kph, whether the engine is started or not is determined according to the power requirement of the whole vehicle, and the vehicle speed is less than 10kph and runs in a pure electric mode.

3) When the SOC of the power battery is 20% -30% (the charging request zone bit of the power battery is established at the moment) and the water temperature of the engine is higher than 60 ℃, the engine is started to charge the power battery when the vehicle speed is higher than 10kph, and the pure electric mode operation mode is adopted when the vehicle speed is lower than 10 kph;

4) when the SOC of the power battery is more than 30%, the opening of an accelerator pedal is less than 95%, the water temperature of an engine is more than 60 ℃, and the vehicle speed is more than 10kph, the engine is allowed to be started, whether the engine is started or not is determined according to the power requirement of the whole vehicle, and the vehicle speed is less than 10kph and runs in a pure electric mode;

as shown in fig. 2, when the vehicle speed is greater than the second set value, the engine is forcibly started, the hybrid vehicle is operated in the hybrid mode, the engine is not allowed to stall, and the second set value is 70 kph.

As shown in fig. 2, when the vehicle control unit receives the charging request flag bit, if the vehicle speed is greater than 10kph, the engine is immediately started to charge the power battery, and the engine is allowed to shut down after the SOC of the power battery is greater than 43%; and if the vehicle speed is less than 10kph, controlling the engine to stop.

When the vehicle control unit receives the forced charging request flag bit, the engine is immediately started to charge the power battery, the charging power of the power battery is 3-5kw greater than that of the power battery when the vehicle control unit receives the charging request flag bit, the SOC of the power battery is charged to be greater than 43%, and the engine is allowed to stop.

Example 1

A control method for the start-stop time of the engine of a hybrid electric vehicle is disclosed, the control flow chart is shown in figure 2, the driving working condition is entered when the water temperature of the engine is 25 ℃ and the SOC of a power battery is 50%, and the steps of the control method for the start-stop time of the engine are as follows:

1. after the whole vehicle is electrified, the whole vehicle is in a D gear, the vehicle controller sends an engine starting instruction according to the judgment of the water temperature of the engine, and the engine is allowed to be flamed out when the water temperature of the engine rises to 60 ℃;

2. under the pure electric working condition, when the vehicle is slowly accelerated to 70kph, the whole vehicle controller sends an engine starting instruction, and when the vehicle speed is more than 70kph, the engine is not allowed to be flamed out;

3. when the accelerator pedal is released and the SOC is more than 30%, the engine immediately stalls when the vehicle speed is reduced to below 70 kph;

4. when the SOC is less than 30%, the vehicle control unit sends an engine starting instruction and a battery charging request flag bit, the engine is started to charge the battery, the battery is charged until the SOC is 43%, the engine is allowed to shut down, and if the SOC is not 43%, the vehicle speed is reduced to be below 10kph, the engine is shut down;

5. if the SOC continues to decrease to 20% or less under condition 4, the engine is forcibly started, the SOC is charged to 43%, and the engine is allowed to stall.

The invention is described above with reference to the accompanying drawings. It is to be understood that the specific implementations of the invention are not limited in this respect. Various insubstantial improvements are made by adopting the method conception and the technical scheme of the invention; the present invention is not limited to the above embodiments, and can be modified in various ways.