Control Method and Control Architecture for Starting Torque Distribution of Hybrid Vehicle Engines

Abstract

The present invention provides a control method and a control architecture for torque distribution during engine starting of a hybrid vehicle. The control method for torque distribution during engine starting of the hybrid vehicle includes: obtaining a starting instruction; determining the starting type; when the starting type is motor starting, entering the motor starting control; judging the oil filling of the clutch and performing torque distribution during the oil filling stage of the clutch; after the oil filling of the clutch is completed, performing torque distribution during the stage of the motor dragging the engine; after the motor dragging the engine is completed, performing torque distribution during the stage of synchronizing the speeds of the motor and the engine; after the speeds of the motor and the engine are synchronized, performing torque distribution during the clutch engagement stage, controlling the clutch to engage, and completing the vehicle engine starting process. The control method for torque distribution during engine starting of the hybrid vehicle according to the present invention can better realize the effectiveness of transient torque calculation and distribution, and improve the running stability and reliability of the vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and more particularly, to a control method and control architecture for starting torque distribution of a hybrid vehicle engine. Background Art

[0002] Hybrid vehicles have good power performance and fuel economy. To meet the requirements of national policies and fuel consumption regulations, more and more automobile manufacturers are developing and promoting hybrid vehicles. Hybrid vehicles mainly obtain power transmission from motors and engines. Based on the coordinated control of torque distribution between motors and engines, not only can a large vehicle driving torque output be achieved, but also the working area of the engine can be optimized, ultimately reducing fuel consumption and emissions and achieving the goal of energy conservation and emission reduction.

[0003] Since hybrid vehicles have two power sources, motors and engines, to output torque, it has an impact on the vehicle driving control and the torque distribution strategy of the power sources. If the torque distribution between the motor and the engine cannot be effectively carried out, it will inevitably affect the vehicle driving control and the performance of vehicle power and economy. During the vehicle driving process, the transient torque distribution strategy of the power system is an important factor affecting the vehicle driving stability. If the transient torque distribution control cannot be effectively carried out, it will inevitably affect the vehicle drivability and driving stability. Therefore, how to accurately and effectively carry out the transient torque distribution control of hybrid vehicles is one of the key problems to be solved at present. Summary of the Invention

[0004] The main object of the present invention is to provide a control method and control architecture for starting torque distribution of a hybrid vehicle engine, which can better realize the effectiveness of transient torque calculation and distribution, and improve the operation stability and reliability of the vehicle.

[0005] To achieve the above object, according to one aspect of the present invention, a control method for starting torque distribution of a hybrid vehicle engine is provided, including:

[0006] Obtain a starting instruction;

[0007] Perform starting type judgment;

[0008] When the starting type is motor starting, enter the motor starting control;

[0009] Perform clutch oil filling judgment and torque distribution during the clutch oil filling stage;

[0010] After the clutch oil filling is completed, control the motor to drag the engine to start and perform torque distribution during the stage of the motor dragging the engine;

[0011] After the motor drives the engine to complete, control the synchronization of the motor and engine speeds, and perform torque distribution during the synchronization stage of the motor and engine speeds;

[0012] After the synchronization of the motor and engine speeds is completed, perform torque distribution during the clutch engagement stage. When the motor speed is greater than the engine idle speed and a command to allow the clutch to engage is received, control the clutch to engage to complete the vehicle engine starting process.

[0013] Further, the steps for performing torque distribution during the clutch oil filling stage include:

[0014] Control the target torque distribution of the clutch to be 0;

[0015] Control the engine not to supply fuel, and control the target torque distribution of the engine to be 0;

[0016] Calculate the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the difference between the transmission input shaft speed request and the motor speed. After being processed by the motor torque limit module, output the motor torque distribution.

[0017] Further, the steps for calculating the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the difference between the transmission input shaft speed request and the motor speed include: Calculate the torque request of the transmission input shaft through the transmission controller and send it to the vehicle controller; Calculate the torque transmitted by the clutch through the clutch control unit and send it to the vehicle controller; Calculate the difference between the transmission input shaft speed request and the motor speed, calculate the PI adjustment torque based on the difference between the transmission input shaft speed request and the motor speed, and send it to the vehicle controller.

[0018] Further, the steps for calculating the difference between the transmission input shaft speed request and the motor speed include: Determine whether the transmission input shaft speed request is between the upper and lower threshold values of the transmission target speed. When the transmission input shaft speed request is between the upper and lower threshold values, the speed request is valid; otherwise, the speed request is invalid. When the transmission input shaft speed request is invalid, output the speed difference as 0. When the transmission speed request is valid, add the preset speed request offset to the motor speed request, compare it with the minimum transmission input shaft speed threshold value, and take the larger of the two to obtain a value. Then subtract the current motor speed from this value to obtain the difference between the transmission input shaft speed request and the motor speed.

[0019] Further, the steps for performing torque distribution during the motor driving engine stage include:

[0020] Obtain the target torque distribution of the clutch based on the engine water temperature and starting time;

[0021] Control the engine not to supply fuel, and control the target torque distribution of the engine to be 0;

[0022] Calculate the sum of the transmission input shaft torque request, the clutch transmitted torque, the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed, and the correction torque, and output the motor torque distribution after being processed by the motor torque limit module.

[0023] Further, the steps of calculating the sum of the transmission input shaft torque request, the clutch transmitted torque, the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed, and the correction torque include:

[0024] Calculate the transmission input shaft torque request through the transmission controller and send it to the vehicle controller;

[0025] Calculate the clutch transmitted torque through the clutch control unit and send it to the vehicle controller;

[0026] Calculate the difference between the transmission input shaft speed request and the motor speed, calculate the PI regulated torque based on the difference between the transmission input shaft speed request and the motor speed, and send it to the vehicle controller;

[0027] Obtain the correction torque by looking up a table according to the engine dragging time and the engine water temperature, and send it to the vehicle controller.

[0028] Further, the steps of performing torque distribution in the motor and engine speed synchronization stage include:

[0029] Control the target torque distribution of the clutch to be 0;

[0030] Obtain the engine target torque distribution according to the motor speed and the speed difference between the motor and the engine;

[0031] Calculate the sum of the transmission input shaft torque request, the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed, and the correction torque, and output the motor torque distribution after being processed by the motor torque limit module;

[0032] Among them, the correction torque is obtained by looking up a table according to the synchronization time of the engine and the motor speeds and the engine water temperature.

[0033] Further, the steps of performing torque distribution in the clutch engagement stage include:

[0034] Calculate the target torque distribution of the clutch according to the sum of the PI regulated torque of the difference between the motor and the engine speeds and the engine torque distribution;

[0035] Calculate the engine torque distribution through the following formula:

[0036] Engine torque distribution = engine torque request + torque offset, where the engine torque request is calculated by the vehicle controller based on the vehicle and powertrain states, and the torque offset is a calibrated value;

[0037] Calculate the sum of the PI regulated torque for the difference between the transmission input shaft speed request and the motor speed and the motor torque request. After being processed by the motor torque limit module, the motor torque distribution is output.

[0038] Furthermore, the motor torque request is obtained through the following steps:

[0039] When the speed difference between the motor and the engine speed is less than the lower limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft;

[0040] When the speed difference between the motor and the engine speed is greater than the upper limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft - the engine torque;

[0041] When the speed difference between the engine and the motor speed is between the upper and lower limits of the synchronous speed difference, the motor torque distribution value is related to the opening of the vehicle's accelerator pedal and is obtained by looking up a table.

[0042] According to another aspect of the present invention, there is provided a starting torque distribution control architecture for a hybrid vehicle engine, including:

[0043] A starting judgment module, including a starting type judgment unit, a clutch oil filling judgment unit, a starting judgment unit, a synchronization judgment unit, and a clutch engagement judgment unit; [[ID=2l]]

[0044] A power control module, including a clutch control unit, an engine control unit, and a motor control unit; and

[0045] A torque distribution module, including a clutch torque distribution unit, an engine torque distribution unit, and a motor torque distribution unit;

[0046] The starting judgment module is communicatively connected to the power control module and transmits the judgment result to the power control module. The power control module is communicatively connected to the torque distribution module. The power control module calculates the torque distribution according to the judgment result and outputs the calculation result to the torque distribution module for torque distribution.

[0047] Applying the technical solution of the present invention, the engine starting torque distribution control method for a hybrid vehicle includes: obtaining a starting instruction; determining the starting type; when the starting type is motor starting, entering the motor starting control; judging the clutch oil filling and performing torque distribution during the clutch oil filling stage; after the clutch oil filling is completed, controlling the motor to drive the engine to start and performing torque distribution during the stage of the motor driving the engine; after the motor driving the engine is completed, controlling the motor and the engine to synchronize their speeds and performing torque distribution during the stage of the motor and the engine speed synchronization; after the motor and the engine speed synchronization is completed, performing torque distribution during the clutch engagement stage. When the motor speed is greater than the engine idle speed and an instruction allowing the clutch to engage is received, controlling the clutch to engage to complete the vehicle engine starting process. This engine starting torque distribution control method for a hybrid vehicle divides the engine starting of the hybrid vehicle into multiple different stages, fully considering the control methods during the clutch oil filling stage, the engine driving stage, the stage of the motor and the engine speed synchronization, and the clutch engagement stage, and designs a clutch torque calculation and distribution control method, an engine torque calculation and distribution control method, and a motor torque calculation and distribution control method that are adapted to the starting stages, which can better realize the effectiveness and reliability of the transient torque calculation and distribution of the hybrid vehicle and improve the vehicle operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0049] Figure 1 shows the power system structure block diagram of a hybrid vehicle according to an embodiment of the present invention;

[0050] Figure 2 shows the structural schematic diagram of the engine starting torque distribution control architecture of a hybrid vehicle according to an embodiment of the present invention;

[0051] Figure 3 shows the starting control process diagram of a hybrid vehicle according to an embodiment of the present invention;

[0052] Figure 4 shows the clutch target torque distribution calculation flow chart of a hybrid vehicle according to an embodiment of the present invention;

[0053] Figure 5 shows the oil filling stage motor target torque distribution calculation flow chart of a hybrid vehicle according to an embodiment of the present invention;

[0054] Figure 6The flowchart of calculating the target torque distribution of the motor in the engine dragging stage of a hybrid vehicle according to an embodiment of the present invention is shown;

[0055] Figure 7 The flowchart of calculating the target torque distribution of the motor in the rotational speed synchronization stage of a hybrid vehicle according to an embodiment of the present invention is shown; and

[0056] Figure 8 The flowchart of calculating the target torque distribution of the motor in the clutch engagement stage of a hybrid vehicle according to an embodiment of the present invention is shown. Detailed implementation manners

[0057] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0058] Refer to in combination Figures 1 to 2 As shown, the present invention provides a torque distribution control architecture for starting the engine of a hybrid vehicle, which is applied to a hybrid vehicle. Refer to Figure 1 As shown, the power system of the hybrid vehicle includes an engine, a motor, a power battery, a gearbox, a clutch and a drive shaft. The motor is connected to the engine through a clutch on one side and to the gearbox on the other side. Each component is controlled by its respective controller. The controllers specifically include an engine control system (EMS, Engine Management System), a vehicle controller (HCU, Hybrid Control Unit), a motor controller (MCU, Motor Control Unit), a battery management system (BMS, Battery Management System), a gearbox controller (TCU, Transmission Control Unit), a clutch control unit (CCU, Clutch Control Unit), etc. Communication between the various controllers is carried out through a CAN network, and the shift controller can be integrated into the gearbox controller.

[0059] Regarding the transient torque distribution control of the hybrid system, it includes torque distribution during the engine starting process and torque distribution during the engine stopping process. The present invention mainly focuses on the transient torque distribution control during the engine starting process of a hybrid vehicle, and the main contents specifically include clutch torque distribution, engine torque distribution, and motor torque distribution.

[0060] Refer to in combination Figure 2As shown, according to an embodiment of the present invention, the starting torque distribution control architecture of a hybrid vehicle engine includes: a starting judgment module, including a starting type judgment unit, a clutch oil filling judgment unit, a starting judgment unit, a synchronization judgment unit, and a clutch engagement judgment unit; a power control module, including a clutch control unit, an engine control unit, and a motor control unit; and a torque distribution module, including a clutch torque distribution unit, an engine torque distribution unit, and a motor torque distribution unit; the starting judgment module is communicatively connected to the power control module and conveys the judgment result to the power control module, the power control module is communicatively connected to the torque distribution module, and the power control module calculates torque distribution according to the judgment result and outputs the calculation result to the torque distribution module for torque distribution.

[0061] In this embodiment, the vehicle controller, as the core controller of the vehicle, executes the software development of transient torque distribution control. In the control architecture, a starting judgment module, a power control module, and a torque distribution module are designed. The functions of the starting judgment module include a starting type judgment unit, a clutch oil filling judgment unit, a starting judgment unit, a synchronization judgment unit, and a clutch engagement judgment unit. Among them, the starting judgment refers to judging the starting of the engine by the motor, and the synchronization judgment refers to judging the synchronization of the motor and engine speeds.

[0062] The starting type judgment unit can judge the starting mode of the motor to determine the starting type of the motor; the clutch oil filling judgment unit can judge whether the clutch oil filling is completed to provide a basis for the next step. The starting judgment unit can judge whether the vehicle starting is completed. The synchronization judgment unit can judge whether the synchronization of the motor and engine speeds is completed. The clutch engagement judgment unit can judge whether the clutch engagement is completed.

[0063] After the starting judgment module completes the judgment of each parameter for starting the motor, the information is transmitted to the power control module. The power control module issues a control command according to the information processed by the starting judgment module and sends it to the torque distribution module. The torque distribution module performs torque distribution according to the received control command.

[0064] There is a corresponding relationship between each control unit of the power control module and each torque distribution unit of the torque distribution module. The clutch control unit is used to control the clutch torque distribution unit to perform the torque distribution of the clutch, the engine control unit is used to control the engine torque distribution unit to perform the torque distribution of the engine, and the motor control unit is used to control the motor torque distribution unit to perform the torque distribution of the motor.

[0065] Combined with reference to Figures 3 to 8As shown, according to an embodiment of the present invention, a control method for the starting torque distribution of a hybrid vehicle engine includes: obtaining a starting instruction; performing starting type judgment; when the starting type is motor starting, entering motor starting control; performing clutch oil filling judgment and torque distribution during the clutch oil filling stage; after the clutch oil filling is completed, controlling the motor to drive the engine to start and performing torque distribution during the stage of the motor driving the engine; after the motor driving the engine is completed, controlling the motor and the engine to synchronize their speeds and performing torque distribution during the stage of the motor and the engine speed synchronization; after the motor and the engine speed synchronization is completed, performing torque distribution during the clutch engagement stage, and when the motor speed is greater than the engine idle speed and an instruction allowing clutch engagement is received, controlling the clutch to engage to complete the vehicle engine starting process.

[0066] This control method for the starting torque distribution of a hybrid vehicle engine divides the starting of the hybrid vehicle engine into multiple different stages, fully considering the control methods during the clutch oil filling stage, the engine driving stage, the motor and engine speed synchronization stage, and the clutch engagement stage. It designs a clutch torque calculation and distribution control method, an engine torque calculation and distribution control method, and a motor torque calculation and distribution control method that are adapted to the starting stages, which can better achieve the effectiveness and reliability of transient torque calculation and distribution of hybrid vehicles and improve the vehicle operation stability.

[0067] In this embodiment, the process of starting the engine of a hybrid vehicle, that is, the control flow of using the motor to drive the engine to start is as Figure 3 shown. The entire control process includes starting type judgment, clutch oil filling, motor driving the engine, motor and engine speed synchronization, and clutch engagement. The relevant judgment conditions and working processes are described as follows.

[0068] Starting type judgment: When the starting type is motor starting, the vehicle is controlled to enter the motor starting mode and enter the clutch oil filling judgment step.

[0069] Clutch oil filling judgment: If the clutch oil filling is not completed, the vehicle controller needs to wait until the clutch oil filling is completed before entering the next process. After the clutch oil filling is completed, it enters the starting judgment step.

[0070] Starting judgment: That is, controlling the process of the motor driving the engine to start. When the clutch oil filling is completed and the engine speed is less than the set speed threshold value (such as 800 rpm), it is controlled to enter the process of the motor driving the engine to start. When the engine speed is greater than or equal to the set speed threshold value (such as 800 rpm), the motor driving the engine is completed and it enters the synchronization judgment step.

[0071] Synchronization judgment: That is, the process of synchronizing the speeds of the motor and the engine. When the engine speed is greater than the speed threshold value (such as 800 rpm), and the speed difference between the motor and the engine is greater than the synchronization speed difference threshold value (such as 100 rpm), then control enters the synchronization process of the motor and the engine. When the engine speed is greater than the speed threshold (such as 800 rpm), and the speed difference between the motor and the engine is less than the synchronization speed difference threshold value (such as 100 rpm), it is considered that the speeds of the motor and the engine are synchronized, and the clutch engagement judgment step is entered.

[0072] Clutch engagement judgment: When the motor speed is greater than the engine idle speed, and the vehicle controller receives an instruction allowing the clutch to engage, control the clutch to engage to complete the vehicle engine starting process.

[0073] The engine starting torque distribution control method for a hybrid vehicle is mainly reflected in four stages, including the clutch oil filling stage, the motor driving the engine stage, the engine and motor speed synchronization stage, and the clutch engagement stage. In each stage, different dynamic component transient torque distributions are involved, specifically including clutch control and torque distribution, engine control and torque distribution, and motor control and torque distribution. The following will specifically introduce how the present invention realizes the engine starting torque distribution control of a hybrid vehicle in different stages.

[0074] In one embodiment, the steps for torque distribution in the clutch oil filling stage include: controlling the target torque distribution of the clutch to be 0; controlling the engine not to supply fuel and controlling the target torque distribution of the engine to be 0; calculating the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and outputting the motor torque distribution after being processed by the motor torque limit module.

[0075] The steps for calculating the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed include: calculating the torque request of the transmission input shaft by the transmission controller and sending it to the vehicle controller; calculating the torque transmitted by the clutch by the clutch control unit and sending it to the vehicle controller; calculating the speed difference between the transmission input shaft speed request and the motor speed, calculating the PI adjustment torque according to the speed difference between the transmission input shaft speed request and the motor speed, and sending it to the vehicle controller. The torque request of the transmission input shaft is calculated by the transmission controller and sent to the vehicle controller through the CAN signal. The torque transmitted by the clutch is calculated by the clutch control unit and sent to the vehicle controller through the CAN signal. The speed difference PI adjustment torque is sent to the vehicle controller through the CAN signal. The motor torque calculation module of the vehicle controller calculates the motor torque according to the received torque request of the transmission input shaft, the torque transmitted by the clutch, and the speed difference PI adjustment torque, and then calculates the motor torque distribution according to the motor maximum and minimum torque limit modules.

[0076] In one embodiment, the steps of calculating the speed difference between the transmission input shaft speed request and the motor speed include: determining whether the transmission input shaft speed request is between the upper and lower threshold values of the transmission target speed (i.e., between the maximum and minimum values of the transmission target speed, and the upper and lower threshold values can be preset and stored in the transmission controller in advance). When the transmission input shaft speed request is between the upper and lower threshold values, the speed request is valid; otherwise, the speed request is invalid. When the transmission input shaft speed request is invalid, the output speed difference is 0. When the transmission speed request is valid, add the preset speed request offset to the motor speed request, compare the result with the minimum speed threshold value of the transmission input shaft, and take the larger of the two to obtain a value. Then, subtract the current motor speed from this value to obtain the speed difference between the transmission input shaft speed request and the motor speed.

[0077] The steps for calculating the PI-regulated torque of the speed difference between the transmission input shaft speed request and the motor are as follows:

[0078] Use the obtained speed difference between the transmission input shaft speed request and the motor speed as the input for PI regulation. The PI-regulated torque calculation is obtained by querying different MAP tables according to different powertrain modes, and the data can be stored in the controller in advance for subsequent query and call.

[0079] Calculated motor torque = transmission input shaft torque + clutch transmission torque + PI-regulated torque;

[0080] The calculated motor torque is processed by the motor maximum and minimum limit module (i.e., the upper and lower limit values) to obtain the motor target torque distribution.

[0081] When the calculated motor torque is greater than the upper limit value of the motor torque, the motor target torque distribution = the upper limit value of the motor torque;

[0082] When the calculated motor torque is less than the lower limit value of the motor torque, the motor target torque distribution = the lower limit value of the motor torque;

[0083] When the calculated motor torque is between the upper and lower limit values of the motor torque, the motor target torque distribution = the calculated motor torque.

[0084] In one embodiment, the steps of performing torque distribution during the stage of the motor dragging the engine include: obtaining the target torque distribution of the clutch according to the engine water temperature and the engine starting time; controlling the engine not to supply fuel and setting the engine target torque distribution to 0; calculating the sum of the transmission input shaft torque request, the clutch transmission torque, the PI-regulated torque of the speed difference between the transmission input shaft speed request and the motor speed, and the correction torque, and outputting the motor torque distribution after processing by the motor torque limit module.

[0085] At this stage, the clutch has to overcome the frictional torque and inertial torque of the engine. The target torque distribution of the clutch can be obtained by looking up a table based on the engine water temperature and starting time. The target torque distribution is shown in Table 1 below. Based on the engine water temperature and starting time, torque calibration can be carried out in advance to form a MAP data table, and the MAP data is stored in the control software of the vehicle controller for direct calling and querying in the later stage.

[0086] Table 1 Clutch Target Torque Distribution

[0087]

[0088] In one embodiment, the steps of calculating the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and the correction torque include: calculating the torque request of the transmission input shaft by the transmission controller and sending it to the vehicle controller; calculating the torque transmitted by the clutch by the clutch control unit and sending it to the vehicle controller; calculating the speed difference between the transmission input shaft speed request and the motor speed, calculating the PI adjustment torque according to the speed difference between the transmission input shaft speed request and the motor speed, and sending it to the vehicle controller; looking up the correction torque according to the engine dragging time and the engine water temperature and sending it to the vehicle controller.

[0089] The calculation methods of the transmission input shaft torque, the torque transmitted by the clutch, and the PI adjustment torque are the same as those of the transmission input shaft torque, the torque transmitted by the clutch, and the PI adjustment torque during the clutch oil filling stage.

[0090] The correction torque is used to control the motor to drag the engine up as soon as possible when the torque transmitted by the clutch is not timely or the PI adjustment has a lag and does not work during the process of the motor dragging the engine. The correction torque can be understood as a kind of torque compensation control strategy. The calculation method of the correction torque is as follows:

[0091] The correction torque is obtained by querying according to the engine dragging time and the engine water temperature, and factors such as the change of the clutch pipeline oil pressure are also considered. The correction torque is obtained by querying based on Table 2 below. Based on the dragging time and engine water temperature parameters, the torque is calibrated in advance, and the MAP data is stored in the HCU control software for direct calling and querying in the later stage.

[0092] Table 2 Correction Torque during the Dragging Process

[0093]

[0094] In one embodiment, the steps of performing torque distribution during the motor and engine speed synchronization stage include: controlling the target torque distribution of the clutch to be 0; obtaining the target torque distribution of the engine based on the motor speed and the speed difference between the motor and the engine; calculating the sum of the torque request of the transmission input shaft, the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and the correction torque, and outputting the motor torque distribution after being processed by the motor torque limit module; wherein the correction torque is obtained by looking up a table based on the synchronization time of the engine and the motor speeds and the engine water temperature.

[0095] In this embodiment, the engine is in the torque control mode during this stage. The target torque distribution of the engine is obtained by looking up a table based on the motor speed and the speed difference between the motor and the engine. The purpose of the control in this stage is to keep the motor and engine speeds synchronized.

[0096] The target torque distribution of the engine is obtained by querying the following Table 3. Based on the motor speed and the speed difference between the motor and the engine, the torque is calibrated in advance, and the MAP data is stored in the control software of the vehicle controller for direct call and query later.

[0097] Table 3 Engine Target Torque Distribution

[0098]

[0099] The motor is in the torque control mode during this stage. The target torque distribution of the motor consists of the sum of three parts: the torque request of the transmission input shaft, the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and the correction torque, and is output after being processed by the motor torque limit module.

[0100] The calculation methods of the torque of the transmission input shaft and the PI adjustment torque are the same as those of the aforementioned torque of the transmission input shaft and the PI adjustment torque.

[0101] The correction torque is a torque compensation strategy used when the PI adjustment torque lags and is ineffective during the synchronization process of the motor and the engine speeds. The calculation method is as follows:

[0102] The correction torque in this embodiment is obtained by querying based on the synchronization time of the engine and the motor speeds and the engine water temperature. The correction torque is obtained by looking up the following Table 4. Based on the synchronization time and the engine water temperature parameters, the torque is calibrated in advance, and the MAP data is stored in the control software of the vehicle controller for direct call and query later.

[0103] Table 4 Correction Torque during Synchronization Process

[0104]

[0105] Calculated value of motor torque = Torque of transmission input shaft + PI adjustment torque + Correction torque;

[0106] The calculated value of the motor torque is processed by the motor maximum and minimum limit module (i.e., the upper and lower limit values) to obtain the target torque distribution of the motor.

[0107] When the calculated value of the motor torque is greater than the upper limit value of the motor torque, the target torque distribution of the motor = the upper limit value of the motor torque;

[0108] When the calculated value of the motor torque is less than the lower limit value of the motor torque, the target torque distribution of the motor = the lower limit value of the motor torque;

[0109] When the calculated value of the motor torque is between the upper and lower limit values of the motor torque, the target torque distribution of the motor = the calculated value of the motor torque.

[0110] In one embodiment, the steps of performing torque distribution in the clutch engagement stage include: calculating the target torque distribution of the clutch according to the sum of the PI adjustment torque of the motor and engine speed difference and the engine torque distribution; calculating the engine torque distribution through the following formula: engine torque distribution = engine torque request + torque offset, where the engine torque request is calculated by the vehicle controller based on the vehicle and powertrain states, and the torque offset is a calibrated value; calculating the sum of the PI adjustment torque of the speed difference between the requested speed of the transmission input shaft and the motor speed and the motor torque request, and outputting the motor torque distribution after being processed by the motor torque limit module.

[0111] The motor torque request is obtained through the following steps: when the speed difference between the motor and engine speeds is less than the lower limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft; when the speed difference between the motor and engine speeds is greater than the upper limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft - the engine torque; when the speed difference between the engine and motor speeds is between the upper and lower limits of the synchronous speed difference, the motor torque distribution value is related to the opening of the vehicle's accelerator pedal and is obtained by looking up a table.

[0112] In this embodiment, in the clutch engagement stage, the calculation of the target torque distribution of the clutch includes the PI adjustment torque of the motor and engine speed difference and the engine torque distribution, and is calculated by the sum of these two parts.

[0113] Calculation method of the speed difference PI adjustment torque: According to the speeds of the motor and engine, through PI adjustment, the speed difference between the motor and engine is made less than the synchronous speed difference threshold value (such as 100 rpm) to obtain the speed difference PI adjustment torque. The calculation of the PI adjustment torque is obtained by querying different MAP tables according to different powertrain modes, and the MAP data can be stored in the controller in advance for subsequent calling and querying.

[0114] Engine Torque Distribution Calculation Method: Engine torque distribution calculation = engine torque request + torque offset. Among them, the engine torque request is the engine torque request calculated by the vehicle controller based on the vehicle (throttle, brake pedal information) and the powertrain status, and the torque offset is a calibrated value. At the same time, torque filtering is required before the engine torque distribution is output.

[0115] Clutch Target Torque Distribution Calculation Method:

[0116] Clutch target torque distribution = rotational speed difference PI adjustment torque + engine torque distribution.

[0117] In this stage, the engine is in the torque control mode, and the engine target torque distribution is the engine torque value calculated by the vehicle controller through the torque distribution module, that is, engine torque distribution = engine torque request + torque offset. Among them, the engine torque request is the engine torque request calculated by the vehicle controller based on the vehicle (throttle, brake pedal information) and the powertrain status, and the torque offset is a calibrated value. Torque filtering is required before the engine torque distribution is output.

[0118] In this stage, the motor is in the torque control mode. The target torque distribution of the motor consists of the sum of the PI adjustment torque of the rotational speed difference between the input shaft rotational speed request of the transmission and the motor rotational speed and the motor torque request, and is output after being processed by the motor torque limit module.

[0119] The calculation method of the PI adjustment torque is the same as that of the PI adjustment torque in the clutch oil filling stage.

[0120] The motor torque request is determined according to the rotational speed difference between the engine and the motor. The upper and lower limits of the rotational speed difference threshold can be set in the control software.

[0121] When the rotational speed difference between the motor and the engine is less than the lower limit of the synchronous rotational speed difference, the motor torque request = the input shaft demand torque of the transmission; when the rotational speed difference between the motor and the engine is greater than the upper limit of the synchronous rotational speed difference, the motor torque request = the input shaft demand torque of the transmission - engine torque. When the rotational speed difference between the engine and the motor is between the upper and lower limits of the synchronous rotational speed difference, the motor torque distribution value is related to the accelerator pedal opening of the vehicle and can be obtained by querying the MAP table. The MAP table is the relationship table between the motor torque request value and the accelerator pedal opening, and is pre-calibrated and stored in the control software.

[0122] Motor torque calculation value = PI adjustment torque + motor torque request;

[0123] The motor torque calculation value is processed by the motor maximum and minimum limit module (i.e., the upper and lower limit values) to obtain the motor target torque distribution;

[0124] When the calculated motor torque is greater than the upper limit value of the motor torque, the motor target torque distribution = the upper limit value of the motor torque;

[0125] When the calculated motor torque is less than the lower limit value of the motor torque, the motor target torque distribution = the lower limit value of the motor torque;

[0126] When the calculated motor torque is between the upper and lower limit values of the motor torque, the motor target torque distribution = the calculated motor torque.

[0127] The starting torque distribution control method for the engine of the hybrid vehicle in the embodiment of the present invention has the following beneficial effects: Different stages of starting the engine of the hybrid vehicle are designed, and the control methods in the clutch oil filling stage, the engine dragging stage, the motor and engine speed synchronization stage, and the clutch engagement stage are fully considered. The clutch torque calculation and distribution control method, the engine torque calculation and distribution control method, and the motor torque calculation and distribution control method are designed; Through the development of control strategies, the effectiveness and reliability of transient torque calculation and distribution for hybrid vehicles are achieved, and the vehicle operation stability is improved.

[0128] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0129] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order different from those illustrated or described herein.

[0130] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A control method for starting torque distribution of a hybrid vehicle engine, characterized in that, Including: Obtain a starting instruction; Judge the starting type; When the starting type is motor starting, enter the motor starting control; Judge the clutch oil filling and perform torque distribution in the clutch oil filling stage; After the clutch oil filling is completed, control the motor to drive the engine to start and perform torque distribution in the stage of the motor driving the engine; after the motor drives the engine to complete, control the motor and the engine speeds to synchronize and perform torque distribution in the stage of the motor and the engine speed synchronization; After the motor and the engine speeds are synchronized, perform torque distribution in the clutch engagement stage. When the motor speed is greater than the engine idle speed and a command to allow the clutch to engage is received, control the clutch to engage to complete the vehicle engine starting process; The steps of performing torque distribution in the stage of the motor and the engine speed synchronization include: Control the target torque distribution of the clutch to be 0; Obtain the engine target torque distribution based on the motor speed and the speed difference between the motor and the engine; Calculate the sum of the torque request of the transmission input shaft, the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and the correction torque, and output the motor torque distribution after being processed by the motor torque limit module; Wherein the correction torque is obtained by looking up a table according to the synchronization time of the engine and the motor speeds and the engine water temperature.

2. The control method for starting torque distribution of a hybrid vehicle engine according to claim 1, wherein The steps of performing torque distribution in the clutch oil filling stage include: Control the target torque distribution of the clutch to be 0; Control the engine not to supply fuel and control the engine target torque distribution to be 0; Calculate the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed, and output the motor torque distribution after being processed by the motor torque limit module.

3. The control method for starting torque distribution of a hybrid vehicle engine according to claim 2, wherein The steps of calculating the sum of the torque request of the transmission input shaft, the torque transmitted by the clutch, and the PI adjustment torque of the speed difference between the transmission input shaft speed request and the motor speed include: Calculate the torque request of the transmission input shaft through the transmission controller and send it to the vehicle controller; Calculate the torque transmitted by the clutch through the clutch control unit and send it to the vehicle controller; Calculate the speed difference between the transmission input shaft speed request and the motor speed, calculate the PI adjustment torque according to the speed difference between the transmission input shaft speed request and the motor speed, and send it to the vehicle controller.

4. The control method for the starting torque distribution of the hybrid vehicle engine according to claim 3, wherein The steps of calculating the speed difference between the transmission input shaft speed request and the motor speed include: Judge whether the transmission input shaft speed request is between the upper and lower threshold values of the transmission target speed. When the transmission input shaft speed request is between the upper and lower threshold values, the speed request is valid, otherwise the speed request is invalid; When the transmission input shaft speed request is invalid, output the speed difference as 0; When the transmission speed request is valid, add the preset speed request offset to the motor speed request, compare it with the minimum speed threshold value of the transmission input shaft, take the larger of the two to get a value, and then subtract the current motor speed from this value to obtain the speed difference between the transmission input shaft speed request and the motor speed.

5. The control method for the starting torque distribution of the hybrid vehicle engine according to claim 1, wherein The steps of performing torque distribution in the stage of the motor driving the engine include: Obtain the target torque distribution of the clutch according to the engine water temperature and the starting time; Control the engine not to supply fuel and control the engine target torque distribution to be 0; Calculate the sum of the transmission input shaft torque request, the clutch transmitted torque, the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed, and the correction torque, and output the motor torque distribution after being processed by the motor torque limit module.

6. The control method for starting torque distribution of a hybrid vehicle engine according to claim 5, characterized in that The steps of calculating the sum of the transmission input shaft torque request, the clutch transmitted torque, the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed, and the correction torque include: Calculate the transmission input shaft torque request through the transmission controller and send it to the vehicle controller; Calculate the clutch transmitted torque through the clutch control unit and send it to the vehicle controller; Calculate the difference between the transmission input shaft speed request and the motor speed, calculate the PI regulated torque based on the difference between the transmission input shaft speed request and the motor speed, and send it to the vehicle controller; Obtain the correction torque by looking up a table according to the engine dragging time and the engine water temperature, and send it to the vehicle controller.

7. The control method for engine starting torque distribution of a hybrid vehicle according to claim 1, characterized in that The steps of performing torque distribution during the clutch engagement stage include: Calculate the target torque distribution of the clutch based on the sum of the PI regulated torque of the difference between the motor and engine speeds and the engine torque distribution; Calculate the engine torque distribution through the following formula: Engine torque distribution = engine torque request + torque offset, where the engine torque request is calculated by the vehicle controller based on the vehicle and powertrain states, and the torque offset is a calibrated value; Calculate the sum of the PI regulated torque of the difference between the transmission input shaft speed request and the motor speed and the motor torque request, and output the motor torque distribution after being processed by the motor torque limit module.

8. The control method for the starting torque distribution of the hybrid vehicle engine according to claim 7, wherein The motor torque request is obtained through the following steps: When the speed difference between the motor and the engine is less than the lower limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft; When the speed difference between the motor and the engine is greater than the upper limit of the synchronous speed difference, the motor torque request = the required torque of the transmission input shaft - the engine torque; When the speed difference between the engine and the motor is between the upper and lower limits of the synchronous speed difference, the motor torque distribution value is related to the accelerator pedal opening of the vehicle and is obtained by looking up a table.

9. A control architecture for a starting torque distribution control method of a hybrid vehicle engine as described in any one of claims 1 to 8, characterized in that, Include: The starting judgment module, including a starting type judgment unit, a clutch oil filling judgment unit, a starting judgment unit, a synchronization judgment unit, and a clutch engagement judgment unit; The power control module, including a clutch control unit, an engine control unit, and a motor control unit; And The torque distribution module, including a clutch torque distribution unit, an engine torque distribution unit, and a motor torque distribution unit; the starting judgment module is communicatively connected to the power control module and conveys the judgment result to the power control module, the power control module is communicatively connected to the torque distribution module, the power control module calculates the torque distribution according to the judgment result, and outputs the calculation result to the torque distribution module for torque distribution.

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