CN102490718B - Control method utilizing motor to start engine for double-clutch type hybrid electric vehicle - Google Patents

Abstract

This method takes a new type of single-motor, dual-clutch hybrid vehicle as the research object, and proposes a control method for the process of the electric motor starting the engine (hereinafter referred to as the electric starter) during driving. Firstly, by analyzing its structural composition and working mode, the system dynamics model is established, the working area of the hybrid electric vehicle is divided, and the corresponding torque management strategy is formulated; then in the actual application process, by calculating the demand torque, battery SOC value and motor speed to judge whether the conditions for starting the engine with the motor are met; when the conditions for starting the motor are met, the mode will be switched, and a command to engage the torque-limiting clutch will be issued, and the hydraulic cylinder oil pressure of the torque-limiting clutch and the specified torque will be coordinated and controlled strategy, coordinate and control the torque of the motor, engine, and the torque of the torque-limiting clutch to realize the process of electric starting. The present invention utilizes the characteristic of rapid response of the motor to increase or decrease the torque of the motor in time according to the control strategy to provide the required torque for starting the engine during driving or compensate for the lack of engine torque, reduce the impact of the switching process, and improve the ride comfort of the hybrid electric vehicle .

Description

Control method for motor starter engine of dual-clutch hybrid electric vehicle

technical field

The invention relates to the technical field of automobile manufacturing, in particular to a single-motor double-clutch hybrid electric vehicle as a research object, and a control method for starting an engine through a motor when the vehicle is running is proposed.

Background technique

Since the 1990s, major automobile companies in Japan, the United States, and Europe have devoted themselves to the development of hybrid vehicles. After entering the 21st century, various countries have accelerated the process of industrialization of hybrid electric vehicles, and successively launched different forms of hybrid electric vehicle products. However, hybrid vehicles have multiple working modes, and there is a process of switching between working modes. During this process, large torque fluctuations are likely to occur, and torque coordination control is required to reduce the impact and improve the operating mode. The smoothness of the switching process. At present, the control of hybrid electric vehicles mainly includes steady-state process control and dynamic process control. The main purpose of the former is fuel economy and optimal emissions, while the main goal of the latter is the power and ride comfort of the vehicle. In terms of structure, the structure of dual motors is often used. Compared with single motors, its main advantage is stable operation, but the cost is higher. As for the strong hybrid electric vehicle with single-motor double-clutch structure in this paper, the structure cost is low, but its dynamic process is complex, and coordinated control is even more important. If the control is not proper, it will cause the motor to start the engine in the process of prolonging the engine starting time, generating a large impact and deteriorating the ride comfort of the car.

Contents of the invention

In view of this, the object of the present invention is to provide a method for controlling the motor starting engine of a dual-clutch hybrid electric vehicle, which utilizes the characteristics of the rapid response of the motor to increase or decrease the motor torque in time according to the control strategy to meet the needs of starting the engine during travel. Torque or compensate for the lack of engine torque, reduce the impact of the switching process, and improve the ride comfort of hybrid vehicles.

The purpose of the present invention is achieved through the following technical solutions:

The control method for the electric motor starting engine of the double-clutch type hybrid electric vehicle is used for the running control of the single-motor double-clutch type hybrid electric vehicle, and comprises the following steps:

Step 1: Analyze its structural composition and working mode, establish a system dynamics model by computer, divide the working area of the hybrid electric vehicle, and formulate corresponding torque management strategies;

Step 2: In the pure electric working state, by calculating the required torque, battery SOC value, and motor speed to determine whether the conditions for starting the engine with the motor are met;

When the conditions for the motor to start the engine are met, the mode will be switched, and the torque-limiting clutch engagement command will be issued. By controlling the oil pressure of the torque-limiting clutch hydraulic cylinder and the formulated torque coordination control strategy, the motor and engine torque will be coordinated and controlled to complete the electric starting process.

Further, said step 2 includes the following steps:

Step 21: The car is running under pure electric conditions, at this time ,in is the motor output torque, Torque is required by the driver, at this time, the motor speed is judged by the controller ,like , If it is the minimum speed of starting the engine, proceed to step 2, otherwise continue to run in pure electric mode;

Step 22: Determine the battery SOC value, if , proceed to step 3, otherwise issue a command to engage the torque-limiting clutch and proceed to step 4; where is the lower limit of the high efficiency area of the battery;

Step 23: If , through the controller to issue a command to engage the torque-limiting clutch, go to step 4, otherwise continue to run in pure electric mode, Minimum torque for engine work;

Step 24: After receiving the command to engage the torque-limiting clutch, after a period of compensation time, the torque-limiting clutch starts to engage and transmit torque, and proceeds with the motor starting process to increase the motor torque, that is , start the engine, where is the maximum torque of the motor, To transmit torque for the torque-limiting clutch, after the structure of the torque-limiting clutch is determined, its value is proportional to the oil pressure;

Step 25: As the engine speed increases, if it reaches its self-ignition operating speed, the engine will be ignited and run, otherwise continue to start the engine;

Step 26: After the engine ignites itself, a torque command is sent to the engine controller, and the engine speeds up. In order to prevent the engine torque change rate from being too large, the engine target torque input in the first 0.2 seconds is , the input engine target torque after 0.2 seconds is , where t is the time elapsed from the self-ignition operation of the engine, between 0 and 0.2;

Step 27: If the motor and the engine rotate at the same speed, the controller determines that the torque-limiting clutch is fully engaged;

If the motor speed is greater than the engine speed, it is considered that the torque limiting clutch is not fully engaged. At this time, the output torque of the motor is , the engine continues to speed up, and the torque-limiting clutch continues to be engaged until it is determined that the torque-limiting clutch is fully engaged;

Step 28: When the torque limiting clutch is fully engaged, use the motor to compensate for the lack of engine torque, and the output torque of the motor at this time is ,in is the compensation torque of the motor. If the compensation torque of the motor is less than , the controller judges that the engine is stable at this time, the motor quits compensation, and only outputs its target torque , the compensation torque is the difference between the engine target torque and its actual output torque;

Otherwise, continue to use the electric motor to compensate for the lack of engine torque until the torque change of the engine is less than , so far, when the motor compensation torque is less than , it is determined that the process of starting the engine is completed, the process of mode switching is completed, and the car is running in the new mode, .

Further, in step 21, the driver demand torque is obtained by the following method:

The required torque applied by the driver on the wheels is converted into the required torque at the output end of the transmission, and the envelope of the maximum driving torque curve in different gears is calculated by the computing unit to obtain the torque demand for 100% of the accelerator pedal stroke, and then obtained Partial pedal stroke torque demand, whose value is equal to the accelerator pedal stroke value multiplied by the torque value of 100% accelerator pedal stroke, so as to establish the calculation model of driver demand torque.

Further, in step 23, The selection method is as follows: Combining the characteristic curve of the motor, the fuel consumption map of the engine and the universal characteristic map of the engine, the working mode area division map of the car is obtained, and the minimum torque curve of the engine can be obtained from this, and the calculation unit is used to establish The calculation model is obtained.

Further, in step 24, the conventional control of the torque-limiting clutch adopts a fuzzy control strategy, including an oil pressure control strategy for initial engagement and an oil pressure control strategy for the slipping stage;

The initial engagement oil pressure control strategy is to multiply the collected accelerator pedal displacement value and the accurate value of the accelerator pedal displacement change rate by their respective quantization factors and , to achieve fuzzification; then according to the fuzzy accelerator pedal displacement and the rate of change of accelerator pedal displacement, combined with the fuzzy control table, the change value of the control quantity is obtained, and then multiplied by the proportional factor , then the controllable quantity within the scope of the basic domain of discourse can be obtained , the initial engagement oil pressure value is the preset initial pressure with clutch oil pressure controllable increments the sum of ;

The oil pressure control strategy in the slipping stage is to multiply the collected accurate values of the accelerator pedal displacement rate of change and the speed difference between the master and slave discs of the clutch by their respective quantization factors and , to achieve fuzzification; then according to the fuzzy change rate of the accelerator pedal displacement and the speed difference between the master and slave discs of the clutch, combined with the fuzzy control table, the change value of the control quantity is obtained, and then multiplied by the proportional factor , then the controllable quantity within the scope of the basic domain of discourse is obtained , after integration, and then added to the initial engagement oil pressure, the clutch engagement oil pressure value can be obtained.

Further, in step 25, The selection method is as follows: Combining the characteristic curve of the motor, the engine fuel consumption map and the universal characteristic map of the engine, the motor power-assisted minimum torque curve is obtained, and the calculation unit is used to establish The calculation model is obtained.

The beneficial effects of the present invention are:

The present invention utilizes the characteristics of rapid response of the motor to increase or decrease the motor torque in time according to the control strategy to provide the required torque for starting the engine during driving or compensate for the lack of engine torque, effectively reducing the impact of the switching process and improving the smoothness of the hybrid electric vehicle sex.

Other advantages, objects and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or can be obtained from It is taught in the practice of the present invention. The objects and other advantages of the invention will be realized and attained by the following description and claims.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:

Figure 1 is a schematic diagram of the layout of a single-motor dual-clutch mechanism for a hybrid electric vehicle;

Figure 2 is an equivalent diagram of the system model;

Figure 3 is a flowchart of the process of starting the engine

Fig. 4 is a driver's torque demand identification diagram;

Figure 5 is a diagram of the area division of the working mode;

Figure 6 Initial pressure rise stage Membership graph;

Figure 7 is the initial pressure rise stage Membership graph;

Figure 8 is the pressure increment Membership graph;

Figure 9 is the sliding grinding stage Membership graph;

Figure 10 is the sliding grinding stage Membership graph;

Figure 11 is the sliding grinding stage Membership graph;

Fig. 12 is a control diagram of the torque limiting clutch.

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are only for illustrating the present invention, but not for limiting the protection scope of the present invention.

As shown in Figure 1, a single-motor dual-clutch mechanism for a hybrid vehicle is a front-drive structure, including a final drive 1, an AMT transmission 2 (that is, an electromechanical automatic transmission), a clutch 3, a motor 4, a one-way Clutch 5, torque-limiting clutch 6 and engine 7; Motor adopts ISG motor. The connection relationship is: the engine 7 and the motor are connected with the torque-limiting clutch through the one-way clutch, the motor shaft is connected with the main clutch, and the main clutch is connected with the AMT transmission, the main reducer, the differential and the half shaft in turn, and finally outputs to the front wheel.

The use of the torque-limiting clutch makes the engagement process of the motor starting the engine stable and controllable, and can ensure that the motor has sufficient output power without power shortage or interruption. The one-way clutch ensures that after the engine is started, the engine speed is not higher than the motor speed, which will not cause excessive slippage of the torque-limiting clutch

When the torque limiting clutch is disconnected, the drive motor can drive the vehicle alone to provide the required torque. During torque limiting clutch engagement, the drive motor can start the engine while propelling the vehicle. After the joining process is completed, the engine and the drive motor can jointly drive the vehicle or be driven by the engine alone.

Dynamic analysis of the process of starting the engine with an electric motor in motion

In order to facilitate dynamic analysis, the model diagram is simplified and the effect of rotational viscous damping is ignored. The obtained model diagram is shown in Figure 2. The meanings of the symbols in the figure are as follows:

- engine output torque; - the clutch transmits torque; - motor output torque; - Converted to the equivalent resistance torque at the rear end of the torque limiting clutch; -Engine speed; -Motor speed; - The equivalent moment of inertia converted to the front end of the clutch; -Equivalent moment of inertia converted to the rear end of the clutch

At the beginning, it is a pure electric working condition: in the case of low speed, low demand torque or low speed operation, the car runs in a pure electric working condition, the torque limiting clutch is disengaged, the engine does not start, and the power required by the car is provided by the electric motor alone. at this time,

, (1)

The dynamic process of starting the engine while driving: When the speed increases or the required torque increases, the motor drive alone cannot meet the demand, and it is necessary to switch from the pure electric working condition to the working condition with the output torque of the engine drive. During this process, the motor not only provides the torque required for the vehicle to run, but also ensures that the engine can be started smoothly. The torque-limiting clutch receives the engagement command and starts to engage the sliding grinding. There is a speed difference between the main and the driven plates. At this time,

(2)

In formula (2), before the engine is ignited and started, is a negative value. When the engine is started and the torque-limiting clutch is fully engaged, the motor does not stop working immediately, but compensates the engine torque to avoid torque fluctuations and affect the smoothness of the mode switching process.

When the engine starts completely and reaches its target torque, the motor does not perform torque compensation to the engine, but only outputs its own required target torque. The torque-limiting clutch is engaged, but the torque is not transmitted, it is transmitted by the one-way clutch, which can reduce the use time of the torque-limiting clutch and prolong its life. at this time,

(3)

In conjunction with the above-mentioned analysis, the control method of the present invention proposes for the hybrid electric vehicle that the above-mentioned mechanism is installed, generally speaking, comprises the following steps:

Step 1: Analyze its structural composition and working mode, establish a system dynamics model by computer, divide the working area of the hybrid electric vehicle, and formulate corresponding torque management strategies;

Step 2: In the pure electric working state, by calculating the required torque, battery SOC value, and motor speed to determine whether the conditions for starting the engine with the motor are met;

When the conditions for the motor to start the engine are met, the mode will be switched, and the torque-limiting clutch engagement command will be issued. By controlling the torque-limiting clutch oil pressure and the formulated torque coordination control strategy, the motor and engine torque will be coordinated and controlled to complete the electric starting process.

The process of step 2 is shown in Figure 3, including the following steps:

Step 21: The car is running under pure electric conditions, at this time ,in is the motor output torque, Torque is required by the driver, at this time, the motor speed is judged by the controller ,like , If it is the minimum speed of starting the engine, proceed to step 2, otherwise continue to run in pure electric mode;

Determining the demanded torque is to determine the working mode of the car and distribute it reasonably to the engine and the motor, which is the basis of the torque distribution control strategy. In this embodiment, the method for determining the driver's demanded torque is as follows:

The required torque applied by the driver on the wheels is converted into the required torque at the output end of the transmission, and the envelope of the maximum driving torque curve in different gears is calculated by the computing unit to obtain the torque demand for 100% of the accelerator pedal stroke, and then obtained Partial pedal stroke torque demand, whose value is equal to the accelerator pedal stroke value multiplied by the torque value of 100% accelerator pedal stroke, so as to establish the calculation model of driver demand torque. Fig. 4 is a driver's torque demand recognition diagram.

Step 22: Determine the battery SOC value, if , proceed to step 3, otherwise issue a command to engage the torque-limiting clutch and proceed to step 4; where is the lower limit of the high efficiency area of the battery;

The actual selection can be based on the data provided by the battery manufacturer and the battery characteristics (for example, 0.4-0.6 is optional).

Step 23: If , through the controller to issue a command to engage the torque-limiting clutch, go to step 4, otherwise continue to run in pure electric mode, Minimum torque for engine work; The selection method is as follows: Combining the characteristic curve of the motor, the fuel consumption map of the engine and the universal characteristic map of the engine, the working mode area division map of the car is obtained, and the minimum torque curve of the engine can be obtained from this, and the calculation unit is used to establish The calculation model is obtained. The minimum engine torque curve is obtained through the following working area division method.

Work area division

Since the engine works at low speed and light load, the efficiency is low. In order to take advantage of the hybrid electric vehicle, it is necessary to divide the working mode area, which is also the premise of mode switching. Combining the characteristic curve of the motor, the fuel consumption map of the engine and the universal characteristic map of the engine, it is ensured that the motor can provide sufficient starting torque and the torque required for the car to run when the engine needs to be started. The division of the working mode area is shown in Figure 5. In Fig. 5, a is the minimum torque curve of the engine, b is the optimal economic curve of the engine obtained through the test, and c is the minimum torque curve of the motor power assist. These curves divide the engine steady-state diagram into different areas, (1) is the pure electric working area, (2) is the single working area of the engine, and (3) is the combined driving area of the engine and the motor. When the engine speed is less than , its efficiency is very low, and the motor can provide a large torque at low speed, so in this area, it is driven by the motor alone to improve economy, and its value can be determined by the characteristics of the engine and motor (for example, it can be set to 800 —1000r/min).

Step 24: After receiving the command to engage the torque-limiting clutch, after a period of compensation time, the torque-limiting clutch starts to engage and transmit torque, and proceeds with the motor starting process to increase the motor torque, that is , start the engine, where is the maximum torque of the motor, To transmit torque for the torque-limiting clutch, after the structure of the torque-limiting clutch is determined, its value is proportional to the oil pressure;

Torque limited clutch oil pressure control

The study of starting the engine while driving does not involve the shifting process of the AMT, so there is no control of the main clutch, mainly the control of the torque-limiting clutch. On the premise of satisfying smoothness, minimize its joining time. During the engagement process, the motor torque and the engagement action of the torque-limiting clutch need to be dynamically coordinated to ensure the normal start of the engine without causing excessive impact on the normal driving of the vehicle. After the structure of the torque limiting clutch is determined, the sliding friction torque depends on the oil pressure acting on the upper limit torque clutch on the friction surface, so it is very important to control the target oil pressure of the torque limiting clutch.

The conventional control of the clutch mostly adopts proportional control, but the relationship between the various quantities is difficult to express with an accurate mathematical model, and the control method cannot meet the requirements, so the fuzzy control strategy is used. The initial pressure of the clutch and the oil pressure control of the clutch in the slipping stage have a great influence on the engagement performance, and are the key points of the clutch control.

(1) The initial oil pressure of the clutch is the preset initial pressure of the clutch with clutch oil pressure increment the sum of . right The evaluation of uses a fuzzy control strategy, Set according to the actual situation. The first input of the fuzzy controller is the accelerator pedal opening , the fuzzy domain of discourse (0, 1), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. The abscissa represents the value of the universe of discourse element, and the ordinate represents the degree of membership of the linguistic variable value. Because the driver is more sensitive when the accelerator pedal is small, but relatively insensitive to large accelerator opening, and the fuzzy subset with a sharper membership function curve has a higher resolution and higher control sensitivity; on the contrary, the membership function curve has a slower shape , smooth control performance, good system stability. Therefore, when selecting the membership function of the fuzzy set of fuzzy variables, the low-resolution fuzzy set is used in the large throttle opening area, and the high-resolution fuzzy set is used in the small throttle opening area. As shown in Figure 6.

The second input is the accelerator pedal opening rate of change , the fuzzy domain of discourse (0, 12), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. Since the control sensitivity requirements for the rate of change of the accelerator pedal stroke are basically the same in the entire domain of discourse, the membership functions used are basically evenly distributed throughout the domain of discourse, as shown in Figure 7.

output as , the fuzzy domain of discourse (0, 12), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. As shown in Figure 8.

Use the center of gravity method to change the control quantity into a precise quantity, and , The control rules among them are shown in Table 1.

In the real-time control process, the collected accelerator pedal displacement value and the accurate value of the accelerator pedal displacement change rate are multiplied by their respective quantization factors and , to achieve fuzzification; then according to the fuzzy accelerator pedal displacement and the rate of change of accelerator pedal displacement, look up the fuzzy control table to obtain the change value of the control variable, and then multiply it by the proportional factor , then the controllable quantity within the scope of the basic domain of discourse can be obtained , the initial engagement oil pressure value is the preset initial pressure with clutch oil pressure controllable increments the sum of .

(2) In the sliding friction stage, it is necessary to consider the driver's operating intention and the degree of clutch engagement. Under the requirement of ensuring low impact, minimize the sliding and grinding process, and use the fuzzy controller to determine the appropriate clutch pressure change rate. The controller also has one output for two inputs. The first input is the accelerator pedal opening rate of change , the fuzzy domain of discourse (0, 1), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. Since the driver wants to speed up the clutch engagement speed when the rate of change of the accelerator pedal displacement is relatively large, the membership function curve is concentrated in the area of the large rate of change of the accelerator pedal displacement to improve the response performance in the area of the large rate of change of the accelerator pedal displacement. The membership function adopts Gaussian function, the degree of membership is shown in Figure 9.

The second input is the absolute value of the clutch disc speed difference , the fuzzy domain of discourse (0, 12), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. When the speed difference between the main and driven discs of the clutch is large, the clutch engagement speed should be slowed down to reduce the impact, but it should not be too slow, which will cause excessive clutch wear; when the speed difference between the main and driven discs of the clutch is small, it should be Accelerate the engagement speed of the clutch to reduce the mode switching time and reduce clutch wear; when the rate of change of the clutch speed difference increases, the clutch engagement speed should be reduced to reduce the impact. The degree of membership is shown in Figure 10.

The output is the clutch engagement pressure rate of change , the fuzzy domain of discourse (0, 12), the fuzzy linguistic variables are {very small, small, small, medium, large, large, very large}, and the corresponding fuzzy subsets are {VS, S, MS, M, MB , B, VB}. The degree of membership is shown in Figure 11.

Use the center of gravity method to change the control quantity into a precise quantity, and and The control rules between them are shown in Table 2.

In the real-time control, the accurate value of the collected accelerator pedal displacement change rate and the clutch disc rotation speed difference is multiplied by the respective quantization factors and , to achieve fuzzification; then according to the fuzzy change rate of the accelerator pedal displacement and the speed difference between the master and slave discs of the clutch, look up the fuzzy control table to obtain the change value of the control variable, and then multiply it by the proportional factor , then the controllable quantity within the scope of the basic domain of discourse is obtained , after integration, and then added to the initial engagement oil pressure, the clutch engagement oil pressure value can be obtained.

The torque-limiting clutch fuzzy control system is shown in Figure 12. By reasonably controlling the initial pressure and the pressure change rate during the sliding and grinding process, the torque fluctuation in the joining process can be effectively resolved and smoothness can be improved.

Step 25: As the engine speed increases, if it reaches its self-ignition operating speed, the engine will be ignited and run, otherwise continue to start the engine;

Step 26: After the engine ignites itself, a torque command is sent to the engine controller, and the engine speeds up. In order to prevent the engine torque change rate from being too large, the engine target torque input in the first 0.2 seconds is , the input engine target torque after 0.2 seconds is , where t is the time elapsed from the self-ignition operation of the engine, between 0 and 0.2;

Step 27: If the motor and the engine rotate at the same speed, the controller determines that the torque-limiting clutch is fully engaged;

If the motor speed is greater than the engine speed, it is considered that the torque limiting clutch is not fully engaged. At this time, the output torque of the motor is , the engine continues to speed up, and the torque-limiting clutch continues to be engaged until it is determined that the torque-limiting clutch is fully engaged;

Step 28: When the torque limiting clutch is fully engaged, use the motor to compensate for the lack of engine torque, and the output torque of the motor at this time is ,in is the compensation torque of the motor. If the compensation torque of the motor is less than , the controller judges that the engine is stable at this time, the compensation torque is the difference between the target torque of the engine and its actual output torque, the motor quits the compensation, and only outputs its target torque ;

Otherwise, continue to use the electric motor to compensate for the lack of engine torque until the torque change of the engine is less than , so far, when the motor compensation torque is less than , it is determined that the process of starting the engine is completed, the process of mode switching is completed, and the car is running in the new mode, .

In this step, the principle of torque coordinated control is: due to the large difference between the torque change time constants of the engine and the motor, if the open-loop control of the engine torque is performed only by the throttle opening, the dynamic torque of the engine will be seriously affected. It lags behind the torque change of the motor, and the torque control of the engine in the dynamic process is also related to the transient air-fuel ratio control and other compensation measures, so that its dynamic performance cannot meet the requirements. Therefore, it is necessary to coordinate and control the torque of the engine and the motor.

Taking advantage of the rapid response of the motor, the engine torque can be compensated by the motor torque. Assuming that the target torque of the engine and the motor is determined to be and , due to the hysteresis of the engine output torque, the actual output torque is , so there is a difference:

(6)

In order to ensure that the total demand torque is stable, the motor is used for compensation, and the actual output torque of the motor , and the relationship between the engine torque is:

(7)

Right now (8)

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (5)

1. the control method of double-clutch type motor of hybrid power automobile fire an engine, the control of advancing for single motor double-clutch type hybrid vehicle, comprises the following steps:

Step 1: its structure composition and mode of operation are analyzed, set up system dynamics model by computing machine, divide the work area of hybrid vehicle, formulate corresponding torque management strategy;

Step 2: under pure electronic mode of operation, judge whether to reach the condition of carrying out electric motor starting driving engine by computation requirement moment of torsion, SOC value of battery, motor speed;

When meeting electric motor starting engine condition, to carry out pattern switching, send torque limiting clutch engagement command, by controlling the moment of torsion coordination control strategy of torque limiting clutch hydraulic actuating cylinder oil pressure and formulation, coordinate to control motor, engine torque, complete electricity and play machine process;

It is characterized in that: described step 2 specifically comprises:

Step 21: automobile moves under pure electronic work condition state, now T _m=T _{d_req}, T wherein _mfor motor output torque, T _{d_req}for chaufeur demand torque, now by controller, judge motor speed n _mif, n _m> n _{e_min}, n _{e_min}for the rotating speed minimum value of fire an engine, carry out step 2, otherwise continue with pure electronic operating mode operation;

Step 22: judgement SOC value of battery, if SOC > is SOC _low, carry out step 3, otherwise send torque limiting clutch engagement command, carry out step 4; SOC wherein _lowfor battery-efficient district lower limit;

Step 23: if T _{d_req}> T _{e_min}, by controller, send torque limiting clutch engagement command, carry out step 4, otherwise continue with pure electronic operating mode operation, T _{e_min}torque minimum value for engine operation;

Step 24: after receiving torque limiting clutch engagement command, through one period of make-up time, torque limiting clutch starts to engage transmitting torque, carries out electricity and plays machine process, increases Motor torque, i.e. T _m=min (T _{d_req}+ T _cl, T _{m_max}), start fire an engine, wherein T _{m_max}for motor maximum torque, T _clfor torque limiting clutch transmitting torque, after torque limiting clutch structure is determined, its value and the proportional relation of oil pressure;

Step 25: along with the increase of engine speed, if reach its Self-lighting working speed, engine ignition operation, otherwise continue fire an engine;

Step 26: after the operation of driving engine Self-lighting, send torque command to engine controller, driving engine speed-raising.Excessive for preventing motor torque rate of change, in first 0.2 second, the engine target torque of input is (T _{e_tar}/ 0.2) * t, at 0.2 second, the engine target torque of input was T afterwards _{e_tar}, wherein t is for to have moved the experienced time at driving engine Self-lighting, between 0 to 0.2;

Step 27: if motor equate with engine speed, controller judges that torque limiting clutch engages completely; If motor speed is greater than engine speed, think that torque limiting clutch does not engage completely, now, the output torque of motor is min (T _{m_max}, T _{d_req}+ T _cl), driving engine continues speed-raising, continues to engage torque limiting clutch, until judge that torque limiting clutch engages completely;

Step 28: after torque limiting clutch engages completely, use the deficiency of motor compensating engine torque, motor output torque is now min (T _{m_max}, T _{m_tar}+ T _bu), T wherein _bufor the compensation torque of motor, if the compensation torque of motor is less than 0.05*T _{e_tar}, controller judges that now driving engine is stable, motor exits compensation, only exports its target torque T _{m_tar}, compensation torque is the difference of engine target moment of torsion output torque actual with it;

Otherwise continue to use the deficiency of motor compensating engine torque, until the change in torque of driving engine is less than 0.05*T _{e_tar}.So far, when motor compensating moment of torsion is less than 0.05*T _{e_tar}, judge that fire an engine process completes, pattern handoff procedure finishes, and automobile moves under new pattern, T _e=T _{e_tar}, T _m=T _{m_tar}.

2. the control method of double-clutch type motor of hybrid power automobile fire an engine according to claim 1, is characterized in that: in step 21, described chaufeur demand torque obtains by the following method:

Chaufeur is applied to the demand torque that demand torque on wheel changes into change-speed box mouth, by calculating unit, calculate out maximum driving torque envelope of curves line under different gears, obtain the torque demand of 100% accelerator travel, and then obtain part pedal stroke torque demand, its value equals the torque rating that accelerator travel value is multiplied by 100% accelerator travel, thereby sets up the computation model of chaufeur demand torque.

3. the control method of double-clutch type motor of hybrid power automobile fire an engine according to claim 1, is characterized in that: in step 23, and T _{e_min}to choose mode as follows: in conjunction with characteristic curve, engine consumption figure and the engine MAP of motor, obtain the mode of operation zoning plan of automobile, can obtain thus engine operation minimal torque curve, by calculating unit, set up T _{e_min}computation model obtain.

4. the control method of double-clutch type motor of hybrid power automobile fire an engine according to claim 1, it is characterized in that: in step 24, the control of torque limiting clutch adopts fuzzy control strategy, comprises initial engagement oil pressure control policy and sliding wear stage oil pressure control policy;

Described initial engagement oil pressure control policy is that the exact value of the accelerator pedal displacement value collecting and accelerator pedal displacement rate of change is multiplied by respectively to quantizing factor K separately _αand K _α', to realize obfuscation; Then according to the accelerator pedal displacement after obfuscation and accelerator pedal displacement rate of change, in conjunction with fuzzy control table, the changing value of controlled amount, then be multiplied by scale factor K _{Δ p}, can obtain the controllable amounts Δ P within the scope of basic domain, initial engagement oil pressure value is default initial pressure P ₀can control increment Delta P sum, i.e. P with clutch pressure _b=P ₀+ Δ P;

Described sliding wear stage oil pressure control policy is that the exact value of the accelerator pedal displacement rate of change collecting and power-transfer clutch principal and subordinate Moving plate speed discrepancy is multiplied by respectively to quantizing factor K' separately _αand K _{Δ ω}, to realize obfuscation; Then according to the accelerator pedal displacement rate of change after obfuscation and power-transfer clutch principal and subordinate Moving plate speed discrepancy, in conjunction with fuzzy control table, the changing value of controlled amount, then be multiplied by factor of proportionality obtain the controllable amounts within the scope of basic domain through integration, then be added and can obtain power-transfer clutch engagement oil value with initial engagement oil pressure.

5. the control method of double-clutch type motor of hybrid power automobile fire an engine according to claim 1, is characterized in that: in step 25, and T _{m_ass}to choose mode as follows: in conjunction with characteristic curve, engine consumption figure and the engine MAP of motor, obtain the mode of operation zoning plan of automobile, can obtain thus the auxiliary minimal torque curve of power of motor, by calculating unit, set up T _{m_ass}computation model obtain.