CN109747624B - A hybrid electric vehicle start-stop control system - Google Patents

Abstract

The invention relates to a hybrid electric vehicle start-stop control system, which comprises a transmission device: to transmit power to the drive wheel; the prime power subsystem: the system is a power system of a raw fuel vehicle, is used for generating source power and is connected with a transmission device through a modified power subsystem; refitting a power subsystem: the hybrid power automobile is used for realizing the starting and stopping of the hybrid power automobile and the hybrid power driving; a controller: the integrated hybrid electric vehicle start-stop control method comprises the steps of collecting input signals through a sensor, judging and controlling a prime power subsystem and a modified power subsystem according to a set condition range, and enabling the hybrid electric vehicle to enter a braking energy recovery mode, a driving mode, an active sliding mode or a neutral sliding mode. Compared with the prior art, the invention has the advantages of convenient modification, low cost, maximized dynamic property and economy and the like.

Description

A hybrid electric vehicle start-stop control system

technical field

The invention relates to the field of hybrid vehicle control, in particular to a start-stop control system for a hybrid vehicle.

Background technique

With the rapid economic development and the acceleration of urbanization, the world is facing the dual pressure of solving the energy crisis and controlling environmental pollution. Among all fossil energy consumptions, the transportation sector accounts for a very high proportion of energy consumption. Among them, the road transportation sector is the largest (accounting for more than 70%) and fastest growing entity in terms of energy consumption and emissions among various transportation modes. The main source of air pollution in big cities. Therefore, increasingly stringent environmental protection and emission regulations have put forward higher requirements for automobile energy saving and emission reduction. Under the premise that electric vehicles cannot be used on a large scale at present, hybrid vehicles have start-stop technology, which can reduce 0.3-0.5L/100km compared to traditional fuel vehicles. It is currently the best choice for comprehensively satisfying emissions, power and economy.

The main problems of the current hybrid vehicle start-stop system are: (1) it cannot be directly modified on the existing model to realize hybrid and start-stop functions; (2) it needs to be implemented on an off-the-shelf hybrid vehicle, and the entire hybrid The vehicle development cycle is long, and the cost of re-development of the production platform is high; (3) the hybrid vehicle power system and transmission system of the application object are complex, and the production cost is high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a start-stop control system for a hybrid electric vehicle in order to overcome the above-mentioned defects of the prior art.

The object of the present invention can be realized through the following technical solutions:

A start-stop control system for a hybrid electric vehicle, comprising:

Transmission: used to transmit power to the drive wheel;

Prime power subsystem: It is the power system of the original fuel vehicle, which is used to generate the source power, and is connected with the transmission device through the modified power subsystem;

Modified power subsystem: used to realize start-stop and hybrid drive of hybrid vehicles;

Controller: integrates the start-stop control method of hybrid electric vehicles, collects input signals through sensors, and judges and controls the original power subsystem and modified power subsystem according to the set condition range, so that the hybrid electric vehicle enters the braking energy recovery mode and driving mode , active coasting mode or neutral coasting mode.

The modified power subsystem includes a 48V power supply, an ISG motor and a first clutch connected in sequence.

The motive power subsystem includes an engine, a second clutch and a transmission, the engine, the second clutch, the first clutch, the transmission and the transmission are connected in sequence, and the engine is a gasoline engine or a diesel engine.

A start-stop control method for a hybrid electric vehicle, comprising the following steps:

1) Read the current operating state signal of the hybrid electric vehicle through the sensor to obtain the operating state of the hybrid electric vehicle;

2) According to the received operating state signal of the hybrid electric vehicle, the controller determines the operating mode of the hybrid electric vehicle, including the braking energy recovery mode, the driving mode, the active coasting mode and the neutral coasting mode, specifically:

21) Determine whether the driver steps on the brakes, if so, execute step 24), if not, execute step 22);

22) Determine whether the accelerator signal is greater than the set value, if so, execute step 25, if not, execute step 23);

23) Determine whether the accelerator signal, the SoC signal of the 48V power supply and the vehicle speed signal are all within the set range, if so, execute step 26), if not, execute step 27);

24) Acquire the current speed of the ISG motor and the gear position of the gearbox, enter the braking energy recovery mode, engage the first clutch, disengage the second clutch, turn off the engine, and the wheels drag the ISG motor backward through the transmission, and return to step 21);

25) Enter the drive mode, and judge whether the current vehicle speed and the SoC signal of the 48V power supply are both within the set range, if so, execute step 28), if not, execute step 29);

26) Enter the active coasting mode, engage the first clutch, disengage the second clutch, turn off the engine, turn on the ISG motor, and return to step 21);

27) Enter the neutral gear coasting mode, disengage the first clutch, engage the second clutch, turn off the engine, the engine reverses the ISG motor, and returns to step 21);

28) Engage the first clutch, disengage the second clutch, turn off the engine, turn on the ISG motor, and return to step 21);

29) Engage the first clutch, engage the second clutch, turn on the engine, turn on the ISG motor, and return to step 21).

In the step 1), the operating status signal includes the accelerator signal, the brake signal, the 48V power SoC signal of the BMS system, the current vehicle speed signal, the engine speed signal, the ISG speed signal and the current gear signal.

When the hybrid vehicle is running in the braking energy recovery mode, if the whole vehicle is in emergency braking or the power SoC is higher than the set threshold, the connection of the ISG motor will be disconnected and the braking energy recovery will be stopped.

The set threshold is 60%.

When the hybrid vehicle is running in drive mode and the engine and ISG motor are driven together:

During normal driving, the controller controls the engine to work in the economic region, and the insufficient torque is provided by the ISG;

When the power SoC is insufficient to maintain the ISG operation, the controller controls the engine to run in pure engine mode.

When the hybrid vehicle runs in the active coasting mode, when the power SoC is lower than the set threshold, the engine is controlled to reverse the ISG to generate electricity.

The set threshold is 50%.

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

1) On the basis of basically retaining the configuration of traditional fuel vehicles, the present invention can be refitted into a hybrid vehicle with start-stop technology, almost retaining the original power system, while taking into account the low emission and high economy, There is also a certain improvement in power.

2) Compared with the direct hybrid vehicle, the refitted hybrid vehicle of the present invention has a low refitting cost, and the total cost is much lower than that of the direct hybrid vehicle.

3) It is divided into four working conditions for start-stop control, which is conducive to maximizing and optimizing its power and economy. The drive mode can ensure power while reducing fuel consumption, the braking energy recovery mode can make full use of the energy consumption during braking, the active coasting mode is conducive to improving the stability of high-speed cruising, and the neutral sliding mode is conducive to the recovery of parking kinetic energy.

Description of drawings

FIG. 1 is a schematic structural diagram of the present invention.

FIG. 2 is a schematic diagram of the control system of the present invention.

FIG. 3 is a flow chart of the control method of the present invention.

Detailed ways

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be pointed out that the content shown in the following drawings is only used to explain this embodiment, but is not limited to this embodiment, and any other embodiments without other creative work still belong to the protection scope of the present invention.

Example

FIG. 1 is a schematic structural diagram of a mild-hybrid vehicle according to an embodiment of the present invention. As shown in FIG. 1 , the main components of the low-hybrid vehicle include a second clutch 1 , a first clutch 2 , a transmission 3 , a transmission 4 , an engine 5 , an ISG motor 6 , a 48V power supply 7 , wheels 8 a and 8 b and a controller 30 , wherein the modified power subsystem 10 includes a 48V power supply 7 , an ISG motor 6 and a first clutch 2 . The prime mover subsystem includes the engine 5 , the second clutch 1 and the transmission 3 .

The low-hybrid vehicle used in this embodiment is modified on the basis of the original traditional fuel vehicle. The original power subsystem 20 is retained, and the modified power subsystem 10 is mainly added. The controller 30 communicates with the modified power subsystem 10 and the original power subsystem 20 through the bus. They are connected separately to realize bidirectional transmission of electrical signals. In this embodiment, the output shaft of the engine 5 transmits power to the first clutch 2 through the second clutch 1, and the first clutch 2 is sequentially connected with the transmission 3 and the transmission device 4 to transmit the power to the wheels 8a and 8b. The 48V power supply 7 is composed of several supercapacitors, and is electrically connected to the ISG motor 6 to conduct bidirectional current. The ISG motor 6 is sequentially connected with the wheels 8a and 8b through the first clutch 2, the transmission 3 and the transmission device 4, so that the bidirectional transmission of power between the wheels 8a and 8b to the ISG6 can be realized.

FIG. 2 is a schematic diagram of a control system of a start-stop system for a weak hybrid vehicle according to an embodiment of the present invention. It mainly includes a 48V system start-stop controller 201 , an input signal 220 and an output signal 230 . The input signal 220 includes the accelerator signal 202 , the brake signal 203 , the 48V power SoC signal 204 , the vehicle speed signal 205 , the engine speed signal 206 , the ISG speed signal 207 and the gear signal 208 . The output signals include an engine torque signal 209 , an engine start-stop signal 210 , an ISG torque signal 211 , a brake pressure signal 212 , a second clutch engagement signal 213 and a first clutch engagement signal 214 .

During the operation of the mild-hybrid vehicle in this embodiment, the 48V system start-stop controller 201 continuously reads the accelerator signal 202 and the brake signal 203 generated by the driver's operation, the 48V power SoC signal 204 from the BMS system, and is collected by the vehicle speed sensor. The current vehicle speed signal 205, the engine speed signal 206 from the built-in engine speed sensor, the ISG speed signal 207 from the motor speed sensor, and the current gear signal 208 from the transmission gear sensor, through the 48V system start-stop controller 201 The internal energy management method can automatically judge and switch between four modes of driving mode/braking energy recovery mode/active coasting mode/neutral coasting mode, and output control signals. Among them, the output engine torque signal 209 and the engine start-stop signal 210 are sent to the engine control unit to control the engine to output the set torque and start-stop respectively; the output ISG torque signal 211 is sent to the motor control unit to control the ISG to generate Set torque; the output brake pressure signal 212 is sent to the brake control unit to control the brake to generate the corresponding braking torque; the output clutch 1 combination signal 213 is sent to the clutch 1 control unit to control the combination and separation of clutch 1; output The clutch 2 engagement signal 214 is sent to the clutch 2 control unit to control the engagement and disengagement of the clutch 2.

FIG. 3 is a flowchart of a control method of a start-stop system for a mild-hybrid vehicle according to an embodiment of the present invention. As shown in FIG. 3 , the steps of the control method of the start-stop system for a weakly mixed vehicle according to an embodiment of the present invention are as follows:

S301, obtain the current accelerator signal, brake signal, SoC signal of the 48V power supply and vehicle speed signal, and transmit the above signals to the 48V start-stop controller.

S302, determine whether the driver steps on the brake. If yes, go to step S305; if not, go to step S303.

S303, determine whether the accelerator signal is greater than a set value. If yes, go to step S306; if not, go to step S304.

S304, determine whether the accelerator signal, the SoC signal of the 48V power supply and the vehicle speed signal are all within the set range, for example, the accelerator is less than 20%, the SoC is greater than 50% and the vehicle speed is less than 60km/h, if yes, go to step S307; if no , step S308 is executed.

S305, obtain the current speed of the ISG motor and the gear position of the transmission.

S306, enter the drive mode.

S307, enter the active gliding mode.

S308, enter the neutral sliding mode.

S309, enter the braking energy recovery mode.

S310, determine that the current vehicle speed and the SoC signal of the 48V power supply are both within the set range, for example, the vehicle speed is less than 10km/h and the SoC is greater than 55%, if yes, go to step S314; if not, go to step S315.

S311, engage the first clutch 2, disengage the second clutch 1, turn off the engine, and turn on the ISG motor.

S312, the first clutch 2 is disengaged, the second clutch 1 is engaged, the engine is turned off, and the engine reverses the ISG motor.

S313, engage the first clutch 2, disengage the second clutch 1, turn off the engine, and the wheels pull the ISG motor backward through the transmission device.

S314, engage the first clutch 2, disengage the second clutch 1, turn off the engine, and turn on the ISG motor.

S315, the first clutch 2 is engaged, the second clutch 1 is engaged, the engine is turned on, and the ISG motor is turned on.

In this embodiment, the energy management strategy covers four modes, namely braking energy recovery mode, driving mode, active coasting mode and neutral coasting mode. Among them, in the braking energy recovery mode, the first clutch 2 is engaged, the second clutch 1 is disengaged, and the engine is turned off. At this time, the vehicle is in a braking state, and the wheels are driven by the transmission mechanism to rotate the ISG motor. When the conditions are met, the 48V power supply is used. Charge. When the ISG motor is reversed, it provides the required part of the braking torque to assist the braking of the vehicle. In the drive mode, when the vehicle speed and the SoC of the 48V power supply are within the set range, the first clutch 2 is engaged, the second clutch 1 is disengaged, the engine is turned off, and the ISG motor is turned on. The ISG motor drives the car to run, which belongs to pure electric drive; When the vehicle speed and the SoC of the 48V power supply are not all within the set range, the first clutch 2 is engaged, the second clutch 1 is engaged, and the engine and the ISG motor are turned on at the same time, which belongs to the hybrid drive. If the SoC of the 48V power supply is not within the range, the engine can reverse the ISG motor to charge the 48V power supply. If the SoC of the 48V power supply is sufficient, the ISG torque can be adjusted to ensure that the engine is in the most economical operating condition and reduce fuel consumption. In the active coasting mode, the first clutch 2 is engaged, the second clutch 1 is disengaged, the engine is turned off, and the ISG motor is turned on. The driver does not step on the accelerator and brakes. At this time, the ISG motor alone drives the vehicle, which can maintain the vehicle speed in this state. In the neutral coasting mode, the first clutch 2 is disengaged, the second clutch 1 is engaged, the engine is turned off, and the vehicle is in a free coasting state. At this time, the engine can reverse the ISG motor to generate electricity.

To sum up, the present invention can be directly applied to a traditional fuel vehicle, converted into a hybrid vehicle with start-stop technology, and almost retains the original power system. Sex also has a certain improvement effect.

The above specific content is a specific description of the present invention in conjunction with the embodiments, and the used embodiments cannot limit the scope of the present invention and its legal protection. For those skilled in the art, as long as other similar modifications are realized without exceeding the concept of the present invention, the principles and usages are the same, all should be regarded as within the scope of the legal protection of the present invention.

Claims (7)

1. a hybrid electric vehicle start-stop control system, is characterized in that, this system comprises: Transmission (4): used to transmit power to the driving wheel; The motive power subsystem (20) is the original fuel vehicle power system, used to generate source power, and is connected to the transmission device (4) by modifying the power subsystem (10), and the motive power subsystem (20) includes an engine (5) ), the second clutch (1) and the transmission (3), the engine (5), the second clutch (1), the first clutch (2), the transmission (3) and the transmission (4) are connected in sequence, so The mentioned engine (5) is a gasoline engine or a diesel engine; A modified power subsystem (10): used to realize start-stop and hybrid driving of a hybrid electric vehicle, the modified power subsystem (10) includes a 48V power supply (7), an ISG motor (6) and a first power source (7) connected in sequence clutch (2); The controller (30): integrates the hybrid electric vehicle start-stop control method, collects input signals through sensors, and judges and controls the motive power subsystem (20) and the modified power subsystem (10) according to the set condition range, so that the hybrid electric vehicle Enter braking energy recovery mode, drive mode, active coasting mode or neutral coasting mode; A start-stop control method for applying a start-stop control system for a hybrid electric vehicle includes the following steps: 1) Read the current operating state signal of the hybrid electric vehicle through the sensor to obtain the operating state of the hybrid electric vehicle; 2) According to the received operating state signal of the hybrid electric vehicle, the controller determines the operating mode of the hybrid electric vehicle, including the braking energy recovery mode, the driving mode, the active coasting mode and the neutral coasting mode, specifically: 21) Determine whether the driver steps on the brakes, if so, execute step 24), if not, execute step 22); 22) Determine whether the accelerator signal is greater than the set value, if so, execute step 25, if not, execute step 23); 23) Determine whether the accelerator signal, the SoC signal of the 48V power supply and the vehicle speed signal are all within the set range, if so, execute step 26), if not, execute step 27); 24) Acquire the current speed of the ISG motor and the gear position of the gearbox, enter the braking energy recovery mode, engage the first clutch, disengage the second clutch, turn off the engine, and the wheels drag the ISG motor backward through the transmission, and return to step 21); 25) Enter the drive mode, and judge whether the current vehicle speed and the SoC signal of the 48V power supply are both within the set range, if so, execute step 28), if not, execute step 29); 26) Enter the active coasting mode, engage the first clutch, disengage the second clutch, turn off the engine, turn on the ISG motor, and return to step 21); 27) Enter the neutral gear coasting mode, disengage the first clutch, engage the second clutch, turn off the engine, the engine reverses the ISG motor, and returns to step 21); 28) Engage the first clutch, disengage the second clutch, turn off the engine, turn on the ISG motor, and return to step 21); 29) Engage the first clutch, engage the second clutch, turn on the engine, turn on the ISG motor, and return to step 21). 2. a kind of hybrid electric vehicle start-stop control system according to claim 1, is characterized in that, in described step 1), operating state signal comprises accelerator signal, brake signal, 48V power SoC signal of BMS system, current Vehicle speed signal, engine speed signal, ISG speed signal and current gear signal. 3. A kind of hybrid electric vehicle start-stop control system according to claim 1, is characterized in that, when the hybrid electric vehicle is running under the braking energy recovery mode, if the whole vehicle is in emergency braking or the power supply SoC is higher than the setting. When the threshold is set, the connection of the ISG motor is disconnected and the braking energy recovery is stopped. 4 . The start-stop control system for a hybrid electric vehicle according to claim 3 , wherein the set threshold is 60%. 5 . 5. A kind of hybrid electric vehicle start-stop control system according to claim 1, is characterized in that, when hybrid electric vehicle is operated in drive mode and is in when engine and ISG motor are jointly driven: During normal driving, the controller controls the engine to work in the economic zone, and the insufficient torque is provided by the ISG; When the power SoC is insufficient to maintain the ISG operation, the controller controls the engine to run in pure engine mode. 6. A hybrid electric vehicle start-stop control system according to claim 1, wherein when the hybrid electric vehicle operates in an active coasting mode, when the power supply SoC is lower than a set threshold, the engine is controlled to reverse the ISG generate electricity. 7 . The start-stop control system for a hybrid electric vehicle according to claim 6 , wherein the set threshold is 50%. 8 .

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