WO2024066914A1

WO2024066914A1 - Gear-shifting control method, gear-shifting control system and dual-electric-motor vehicle

Info

Publication number: WO2024066914A1
Application number: PCT/CN2023/116338
Authority: WO
Inventors: 周文太; 于锋; 朱永明; 王金航; 张安伟; 祁宏钟
Original assignee: 广州汽车集团股份有限公司
Priority date: 2022-09-30
Filing date: 2023-08-31
Publication date: 2024-04-04
Also published as: CN117841970A

Abstract

A gear-shifting control method, comprising: when a specified gear-shifting switching signal is received, a dual-electric-motor vehicle (1000) switching from the mode where an engine (1) provides a wheel-end torque by means of an input shaft (8) to the mode where a second electric motor (3) provides the wheel-end torque; the dual-electric-motor vehicle (1000) controlling a brake (4) to engage with a sun gear (13); the dual-electric-motor vehicle (1000) using a first electric motor (2) to adjust the rotational speed of the engine (1) to a target rotational speed of the engine (1) corresponding to a target gear; the dual-electric-motor vehicle (1000) controlling a clutch (5) to be in an engaged state; and the dual-electric-motor vehicle (1000) switching from the mode where the second electric motor (3) provides the wheel-end torque to the mode where the engine (1) provides the wheel-end torque by means of the input shaft (8). During gear-shifting switching, the second electric motor (3) is used to maintain the torque required by a vehicle wheel end, and after the switching is completed, the engine (1) is used to provide the torque required by the vehicle wheel end, thus achieving a smooth transition of the wheel end torque, and having great smoothness. Further provided are a gear-shifting control system and a dual-electric-motor vehicle.

Description

Gear shift control method, gear shift control system and dual-motor vehicle

This application claims priority to the Chinese patent application filed with the China Patent Office on September 30, 2022, with application number 202211216918.0 and application name “Shift Control Method, Shift Control System and Dual-Motor Vehicle”, the entire contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of vehicle control, and in particular to a gear shift control method, a gear shift control system and a dual-motor vehicle.

Background technique

Hybrid vehicles equipped with new electromechanical coupling devices can select working modes according to working conditions to achieve high efficiency and fuel saving. New electromechanical coupling devices often have multiple working modes such as pure electric, series hybrid or power split, parallel hybrid, etc. However, during the mode switching process, it may be accompanied by forward rushing, shaking, and setbacks, resulting in a poor driving experience for users. Therefore, mode switching smoothness control is one of the key technologies of hybrid vehicles.

Conventional dual clutch transmissions (DCT) or multi-speed electromechanical coupling systems often use a clutch-to-clutch shifting strategy. This shifting strategy is to achieve gear switching by releasing the meshing mechanism before the speed change and engaging the meshing mechanism after the speed change. Therefore, the above-mentioned shifting strategy often has a large demand for the instantaneous sliding friction power and sliding friction work capacity of the clutch, resulting in problems such as increased costs of the clutch and hydraulic system and overly complex control software.

Summary of the invention

In view of this, it is necessary to provide a gear shift control method, a gear shift control system and a dual-motor vehicle, aiming to solve the technical problems of smooth mode switching and complex operation in the prior art.

A shift control method is applied to a dual-motor vehicle; the dual-motor vehicle includes an engine, a first motor, a second motor, a brake, a clutch and a vehicle wheel end, and the shift control method includes:

When receiving a designated shift switching signal, the dual-motor vehicle switches the wheel-end torque provided by the engine through the input shaft to the wheel-end torque provided by the second motor;

The dual-motor vehicle controls the brake to be combined with the sun gear;

The dual-motor vehicle uses the first motor to adjust the speed of the engine to a target engine speed corresponding to a target gear position;

The dual-motor vehicle controls the clutch to be in an engaged state;

The dual-motor vehicle switches the wheel-end torque provided by the second motor to the wheel-end torque provided by the engine through the input shaft.

A gear shift control system comprises a memory and a processor; the processor is used to implement the above-mentioned gear shift control method when executing the computer program code stored in the memory.

A dual-motor vehicle comprises a memory and a processor; the processor is used to implement the above-mentioned shift control method when executing a computer program code stored in the memory.

The above-mentioned shift control method, shift control system and dual-motor vehicle use the second motor to maintain the torque required by the vehicle wheel end during the shifting, and use the engine to provide the torque required by the vehicle wheel end after the shifting is completed, so as to achieve a smooth transition of the wheel end torque during the mode switching process and have good ride comfort. At the same time, the performance requirements for the brake, clutch and other components during the shifting process are reduced, and the service life of the brake, clutch and other components can be increased. At the same time, the complexity of the shifting process of the dual-motor vehicle is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a dual-motor vehicle according to a preferred embodiment of the present application.

2 is a waveform diagram of the engine speed, input shaft torque, second motor torque, specified oil pressure, and clutch oil pressure when the dual-motor vehicle of FIG. 1 switches from the parallel hybrid first gear mode to the parallel hybrid second gear mode.

FIG. 3 is a lever diagram of a dual-motor vehicle before the first stage.

FIG. 4 is a lever diagram of the dual motor vehicle at the end of the first phase.

FIG. 5 is a schematic diagram of the levers of the dual-motor vehicle in the third stage.

FIG. 6 is a schematic diagram of the levers of the dual-motor vehicle in the fifth stage.

FIG. 7 is a module diagram of the operating environment of a dual-motor vehicle according to a preferred embodiment of the present application.

FIG. 8 is a flow chart of a gear shift control method according to a preferred embodiment of the present application.

FIG. 9 is a schematic diagram of a detailed flow chart of step S16 in FIG. 8 .

Detailed ways

In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.

In the description of the implementation methods of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate connection, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be immediately understood according to specific circumstances.

The terms "first", "second", and "third" in the specification of this application and the above drawings are used to distinguish different objects rather than to describe a specific order. In addition, the term "includes" and any of their variations are intended to cover non-exclusive inclusions.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

The gear shift control system, gear shift control method and specific implementation methods of the dual-motor vehicle of the present application are described below in conjunction with the accompanying drawings.

Please refer to FIG1 , which is a schematic diagram of the structure of a dual-motor vehicle 1000 according to an embodiment of the present application. The dual-motor vehicle 1000 includes an engine 1 , a first motor 2 , a second motor 3 , a brake 4 , a clutch 5 , a differential 6 , and a vehicle wheel end 7 .

The engine 1 is used to provide power. The engine 1 is connected to the first motor 2, and is connected to the second motor 3 through the input shaft 8, the planetary gear ring 9, the planetary carrier 10, the first gear 11 and the second gear 12. The brake 4 is connected to the sun gear 13. At the same time, the sun gear 13 is meshed with the planetary carrier 10, and the planetary carrier 10 is meshed with the planetary gear ring 9. The clutch 5 is connected to the planetary gear ring 9. The brake 4 cooperates with the clutch 5 to achieve the gear shift of the engine 1. Further, the first gear 11 is connected to the differential 6 and the two vehicle wheel ends 7 through the intermediate shaft 14, the third gear 15 and the fourth gear 16.

When the brake 4 is engaged, the power of the engine 1 is transmitted to the planetary carrier 10 through the planetary ring gear 9, and is transmitted to the intermediate shaft 14 through the first gear 11, and is further transmitted to the differential 6 and the vehicle wheel end 7 through the third gear 15 and the fourth gear 16. At this time, the power is provided by the engine 1, and the engine 1 is in the first gear of the parallel hybrid. At the same time, the first motor 2 and the second motor 3 can provide auxiliary power.

When the clutch 5 is engaged, the sun gear 13, the planetary carrier 10, and the planetary ring gear 9 rotate synchronously as a whole, and the generated power is transmitted to the intermediate shaft 14 through the planetary carrier 10 and the first gear 11, and further transmitted to the intermediate shaft 14 through the third gear 15 and the fourth gear 16. The gear 16 transmits to the differential 6 and the vehicle wheel end 7. At this time, the engine 1 provides power, and the engine 1 switches to the parallel hybrid second gear. At the same time, the first motor 2 and the second motor 3 can provide auxiliary power.

The dual-motor vehicle 1000 has four modes, namely, a pure electric mode, a series hybrid mode, a parallel hybrid first gear mode, and a parallel hybrid second gear mode. The dual-motor vehicle 1000 actively switches between the above modes according to parameters such as the throttle, vehicle speed, and battery state of charge (SOC).

The dual-motor vehicle 1000 also includes an engine management module (Engine management system) 100, a first motor controller (Power control unit, PCU) 200, a second motor controller 300, a vehicle control module (Vehicle control unit, VCU) 400 and a battery management system (Battery management system) 500.

The engine management system 100 is electrically connected to the engine 1. The engine management system 100 is used to sense parameters such as the engine speed and the actual engine torque of the engine 1 when the engine 1 is working.

The first motor controller 200 is electrically connected to the first motor 2. The first motor controller 200 is used to output the first motor torque to the first motor 2 to control the rotation of the first motor 2.

The second motor controller 300 is electrically connected to the second motor 3. The second motor controller 300 is used to output the second motor torque to the second motor 3 to control the rotation of the second motor 3.

The vehicle control module 400 is electrically connected to the engine management system 100, the first motor controller 200, the second motor controller 300 and the battery management system 500. The vehicle control module 400 communicates with the engine management system 100 to obtain multiple engine parameters of the engine 1 and obtain the wheel end torque demand of the vehicle wheel end 7. In at least one embodiment of the present application, the engine parameters are the engine speed and the actual engine torque. The vehicle control module 400 calculates the actual engine power according to the engine parameters and the wheel end torque demand, and calculates the wheel end required power according to the vehicle speed, tire radius and wheel end torque demand of the dual motor vehicle 1000. The vehicle control module 400 compares the engine required power and the wheel end required power and outputs the first motor parameter to the first motor controller 200 according to the comparison result to adjust the operation of the first motor 2. The vehicle control module 400 outputs the second motor parameter to the second motor controller 300 to adjust the operation of the second motor 3. In at least one embodiment of the present application, the first motor parameter is the first motor transmission ratio, and the second motor parameter is the second motor transmission ratio.

For example, in the parallel hybrid first gear mode, the vehicle control module 400 obtains the engine speed and actual engine torque of the engine 1 and the wheel end torque demand through the engine management system 100. In at least one embodiment of the present application, the wheel end torque demand is obtained by looking up the table according to the accelerator pedal and vehicle speed signal.

The vehicle control module 400 obtains the engine torque demand by looking up the following table 1 according to the engine speed and the wheel end torque demand and sends it to the engine management system 100.

Table 1 Relationship between engine speed, wheel end torque demand and engine torque demand

Among them, Table 1 can use the exhaustive method or dynamic rules based on working conditions to set the initial table and optimize the initial table content according to the actual vehicle.

The vehicle control module 400 further calculates the actual engine power and the wheel-end required power, and controls the working mode of the first motor 2 or the second motor 3 according to the comparison result between the two. When the power required by the wheel end is less than the actual power of the engine, the vehicle control module 400 controls the first motor 2 to generate electricity through the first motor controller 200 and provides it to other components of the dual-motor vehicle 1000, such as the air-conditioning compressor, audio and charging interface of the dual-motor vehicle 1000, etc., which are not limited here.

The actual engine power can be calculated using the following formula 1.

Wherein, P _ICEActl is the actual engine power; n _ICE is the engine speed; T _ICEActl is the actual engine torque; V is the speed of the dual-motor vehicle 1000; and r is the tire radius of the dual-motor vehicle 1000.

The wheel end power requirement can be calculated using the following formula 2.

Wherein, P _Wheel is the required power of the vehicle wheel end; T _WheelReq is the required torque of the vehicle wheel end; V is the speed of the dual-motor vehicle 1000; and r is the tire radius of the dual-motor vehicle 1000.

The vehicle control module 400 further calculates the first motor torque requirement or the second motor torque requirement and sends it to the first motor controller 200 and the second motor controller 300 .

The first motor torque requirement can be calculated using the following formula three.

Among them, T _EM1toICE is the torque demand of the second motor; T _WheelReq is the vehicle wheel-end torque demand; i _ICE1 is the transmission ratio from engine 1 to wheel in the parallel hybrid first gear mode; T _ICEActl is the actual engine torque; i _EM1toICE is the transmission ratio from the first motor 2 to engine 1 in the parallel hybrid first gear mode.

The second motor torque requirement can be calculated using the following formula 4.

Among them, T _EM2toICE is the torque demand of the second motor; T _WheelReq is the vehicle wheel end torque demand; T _ICEActl is the actual engine torque; i _ICE1 is the transmission ratio from engine 1 to vehicle wheel end 7 in the parallel hybrid first gear mode; i _EM2toWheel is the transmission ratio from the second motor 3 to the vehicle wheel end 7 in the parallel hybrid first gear mode.

Further, upon receiving the designated gear shift signal, the vehicle control module 400 switches the wheel end torque provided by the engine 1 through the input shaft 8 to the wheel end torque provided by the second motor 3, and uses the first motor 2 to adjust the speed of the engine 1 to the target engine speed in the parallel hybrid second gear, and then switches the wheel end torque provided by the second motor 3 to the wheel end torque provided by the engine 1 through the input shaft 8, so that the torque of the vehicle wheel end 7 smoothly transitions during the gear shift process. In at least one embodiment of the present application, the designated gear shift switching signal instructs the dual-motor vehicle 1000 to switch from the parallel hybrid first gear to the parallel hybrid second gear.

During the gear shifting process, the vehicle control module 400 works in the first stage T1, the second stage T2, the third stage T3, the fourth stage T4 and the fifth stage T5 in sequence.

Please refer to Figures 2 and 3, which are waveform diagrams of the engine speed, input shaft torque, second motor torque, designated oil pressure, and clutch oil pressure when the dual-motor vehicle 1000 switches from the parallel hybrid first gear mode to the parallel hybrid second gear mode. Figure 3 is a lever diagram of the dual-motor vehicle 1000 before the first stage T1. In the first stage T1 (torque exchange stage), the vehicle control module 400 controls the brake 4 to be in an engaged state and the clutch 5 to be in a disengaged state. The vehicle control module 400 further switches the wheel-end torque provided by the engine 1 through the input shaft 8 to the wheel-end torque provided by the second motor 3. Specifically, the vehicle control module 400 controls the input shaft torque to decrease in a step-by-step manner with a first step length at predetermined intervals, and controls the second motor torque to increase in a step-by-step manner with a first step length at predetermined intervals to maintain the wheel-end torque of the vehicle wheel end 7 unchanged. In at least one embodiment of the present application, the predetermined time is 10 milliseconds. Seconds (ms).

The change of input shaft torque can be calculated according to the following formula 5.

Wherein, T _Input is the input shaft torque; T _{InputlastValue} is the value of the input shaft torque at the previous moment; T _WheelGrad is the first step length; i _ICE1 is the transmission ratio from engine 1 to vehicle wheel end 7 in the parallel hybrid first gear mode.

The change mode of the second motor torque can be calculated according to the following formula six.

Among them, T _EM2REQ is the torque of the second motor; T _{EM2REQLasValue} is the torque value of the second motor at the previous moment; T _WheelGrad is the first step length; i _EM2toWheel is the transmission ratio of the second motor 3 to the vehicle wheel end 7 in the parallel hybrid first gear mode, and T _WheelReq is the wheel end torque demand.

After the torque exchange is completed, the input shaft torque T _Input provided by the engine 1 to the input shaft 8 is 0, and the wheel end torque of the vehicle wheel end 7 is provided by the second motor torque T _EM2REQ of the second motor 3. Further, the first motor torque demand can be calculated according to the following formula 7.

Among them, T _EM1REQ is the torque of the first motor; T _Input is the input shaft torque; T _ICEActl is the actual torque of the engine; i _EM1toICE is the transmission ratio of the first motor 2 to the engine 1 in the parallel hybrid first gear mode.

Please also refer to FIG. 4 , which is a lever diagram of the dual-motor vehicle 1000 at the end of the first stage T1 . As can be seen from FIG. 4 , the engine 1 stops providing power through the input shaft 8 .

In the second stage T2, the vehicle control module 400 controls the brake 4 to engage with the sun gear 13. In at least one embodiment of the present application, the vehicle control module 400 controls the oil pressure of the brake 4 to decrease to a half-engagement point (Kiss point, KP) so that the brake 4 is engaged with the sun gear 13.

Please also refer to Figure 5, which is a lever diagram of the dual-motor vehicle 1000 in the third stage T3. In the third stage T3 (speed synchronization stage), the vehicle control module 400 controls the dual-motor vehicle 1000 to operate in the series hybrid mode. At this time, the brake 4 and the clutch 5 are both in a disengaged state. In the series hybrid mode, the vehicle control module 400 uses the first motor 2 to adjust the speed of the engine 1 to the target engine speed in the parallel hybrid second gear. In the current series hybrid mode, the engine power demand includes the second motor demand and the power demand of other components. That is, part of the engine power is provided to the second motor 3, and the other part is provided to other accessories.

Specifically, the vehicle control module 400 calculates the target engine speed and obtains the engine power requirement based on the second motor torque obtained in the first stage T1. The target speed is the engine speed after the gear shift, that is, the engine speed in the second gear of the parallel hybrid.

Since the second motor 3 provides power to the vehicle wheel end 7 at the end of the first stage T1 , the vehicle control module 400 can calculate the second motor torque demand according to the wheel end torque demand and send it to the second motor controller 300 .

The second motor torque requirement can be calculated according to the following formula eight.

Among them, T _EM2REQ is the torque demand of the second motor; T _WheelReq is the vehicle wheel end torque demand, and i _EM2TOWheel is the transmission ratio from the second motor 3 to the vehicle wheel end 7 in the parallel hybrid second gear mode.

The vehicle control module 400 further calculates the engine power requirement. Therefore, the engine power requirement can be calculated according to the following formula 9.

Wherein, P _ICEREQ is the engine power demand; P _EM2REQ is the second motor power demand; P _Accessory is the power demand of other components; n _EM2 is the second motor speed; T _EM2REQ is the second motor torque; η _EM2 is the second motor system efficiency; η _EM1 is the conversion efficiency of engine mechanical power to engine electrical power.

The target engine speed can be calculated using the following formula.

Wherein, n _ICEREQ is the target engine speed; i _ICE2 is the transmission ratio from engine 1 to the wheels in the parallel hybrid second gear mode, V is the speed of the dual-motor vehicle 1000, and r is the tire radius of the dual-motor vehicle 1000.

The vehicle control module 400 calculates the engine torque demand according to the engine target speed and the engine power demand and sends it to the engine management system 100. The engine torque demand can be calculated according to the following formula 11.

Among them, _{TICEREQ is} the engine torque demand; _PICEREQ is the engine power demand; _nICEREQ is the engine target speed; _TICEMAX is the maximum torque at the current engine speed.

The vehicle control module 400 calculates the speed difference between the target engine speed and the current actual engine speed, and calculates the first motor torque demand based on the speed difference based on the proportional integral (PI) control algorithm. The first motor torque demand can be calculated according to the following formula 12.

Among them, T _EM1REQ is the first motor torque; T _EM1LastValue is the value of the first motor torque at the previous moment; K _P is the P value of the PI controller and is a calibration value; Δn is the speed difference; T ₁ is the I value of the PI controller and is a calibration value.

In at least one embodiment of the present application, the first motor torque demand serves as a feedback torque demand, which, together with the second motor torque demand, causes the engine speed to be adjusted to the target speed.

In the fourth stage T4, the vehicle control module 400 controls the clutch 5 to be in the engaged state. In at least one embodiment of the present application, the vehicle control module 400 controls the clutch 5 to load the oil pressure (as shown in FIG. 4 ) when detecting that the speed difference between the two ends of the clutch 5 is within 50 revolutions per minute (rpm), thereby realizing that the clutch 5 is in the engaged state.

Please refer to FIG. 6 , which is a lever diagram of the dual-motor vehicle 1000 at the fifth stage T5. In the fifth stage T5 (torque exchange stage), the vehicle control module 400 controls the brake 4 to be in a disengaged state and keeps the clutch 5 in a coupled state. In this stage, the vehicle control module 400 exchanges the wheel-end torque provided by the second motor torque for the wheel-end torque provided by the engine torque. Specifically, the vehicle control module 400 again obtains the engine torque demand by looking up the table 1 according to the engine speed and the wheel-end torque demand in the parallel hybrid second gear and sends it to the engine management system 100. The vehicle control module 400 further controls the second motor 3 to provide auxiliary power through the second motor controller 300 to meet the wheel-end power demand when the wheel-end power demand is greater than or equal to the actual engine power. When the wheel-end power demand is less than the actual engine power, the vehicle control module 400 controls the first motor 2 to generate electricity through the first motor controller 200 and provides it to other components of the dual-motor vehicle 1000.

The vehicle control module 400 further calculates the first motor target power or the second motor target power according to the actual engine torque and the wheel end torque demand.

Among them, the target power of the first motor can be calculated according to the following formula 13.

Among them, T _EM1toICE is the target torque of the first motor; T _WheelReq is the vehicle wheel end torque requirement; i _ICE2 is the transmission ratio from the engine 1 to the vehicle wheel end 7 in the parallel hybrid second gear mode; T _ICEActl is the actual engine torque; i _EM1toICE is the transmission ratio from the first motor 2 to the vehicle wheel end 7 in the parallel hybrid second gear mode.

The second motor target torque can be calculated according to the following formula 14.

Among them, T _EM2toICE is the target torque of the second motor; T _WheelReq is the vehicle wheel-end torque requirement; T _ICEActl is the actual engine torque; T _{EM2REQLasValue} is the torque value of the second motor at the previous moment; i _ICE2 is the transmission ratio from the engine 1 to the vehicle wheel end 7 in the parallel hybrid second gear mode; i _EM2toICE is the transmission ratio from the second motor 3 to the vehicle wheel end 7 in the parallel hybrid second gear mode.

The vehicle control module 400 further controls the input shaft torque to increase in a step-by-step manner at a second step length at predetermined intervals, and controls the second motor torque to decrease in a step-by-step manner at a second step length at predetermined intervals. In at least one embodiment of the present application, the predetermined time is 10 milliseconds (ms) to maintain the wheel end torque of the vehicle wheel end 7 unchanged. The second step length may be the same as or different from the first step length.

The input shaft torque can be calculated according to the following formula 15.

Among them, T _Input is the input shaft torque; T _{InputlastValue} is the value of the input shaft torque at the previous moment, T _WheelGrad2 is the second step size; i _ICE2 is the transmission ratio from engine 1 to vehicle wheel end 7 in the parallel hybrid second gear mode; T _EM1Target is the target torque of the first motor; i _EM1toWheel is the transmission ratio from the first motor 2 to the vehicle wheel end 7 in the parallel hybrid second gear mode; T _ICEREQ is the required engine torque.

The second motor torque requirement can be calculated according to the following formula six.

Among them, T _EM2REQ is the torque of the second motor; T _{EM2REQLasValue} is the torque value of the second motor at the previous moment; T _WheelGrad2 is the second step size; i _EM2toWheel is the transmission ratio of the second motor 3 to the vehicle wheel end 7 in the parallel hybrid second gear mode, and T _EM2Target is the target torque requirement of the second motor.

After completing the torque exchange, the engine 1 provides the input shaft torque T _Input to the input shaft 8 as the main provider of wheel-end torque.

In the above dual-motor vehicle 1000, when the parallel hybrid first gear is switched to the parallel hybrid second gear, the vehicle control module 400 uses the second motor 3 to maintain the torque required by the vehicle wheel end 7, and uses the engine 1 to provide the torque required by the vehicle wheel end 7 after the switching is completed, so as to achieve a smooth transition of the wheel end torque during the mode switching process, and has good smoothness. At the same time, the performance requirements for the brakes, clutches and other components during the gear shifting process are reduced, and the service life of the brakes, clutches and other components can be improved. At the same time, the complexity of the gear shifting process of the dual-motor vehicle 1000 is reduced.

Please refer to Fig. 7, which is a schematic diagram of a module of an application environment of a dual-motor vehicle 1000. The dual-motor vehicle 1000 further includes a memory 102, a processor 103, a communication bus 104, and a network interface 105. The network interface 105 is used to establish data communication between the dual-motor vehicle 1000 and a server or other electronic devices.

The memory 102 is used to store program codes. The memory 102 may be a circuit with storage function in an integrated circuit without a physical form, such as a memory stick, a TF card (Trans-flash Card), a smart media card, a secure digital card, a flash memory card, and other storage devices. The memory 102 may communicate data with the processor 103 via a communication bus 104. The memory 102 may include an operating system A and a shift control system B. The operating system A is a program for managing and controlling the hardware and software resources of the dual-motor vehicle 1000, and supports the operation of the shift control system B and other software and/or programs.

The processor 103 may include one or more microprocessors or digital processors. The processor 103 may call the program code stored in the memory 102 to execute related functions. The processor 103, also known as the central processing unit (CPU), is a large-scale integrated circuit, which is a computing core (Core) and a control core (Control Unit). For example, the shift control system B is a program code stored in the memory 102 and executed by the processor 103 to implement a shift control method.

Furthermore, the shift control system B can communicate with components such as the engine 1, the first motor 2, the second motor 3, the brake 4, the clutch 5, the differential 6 and the vehicle wheel end 7 to execute the shift control method.

Please refer to FIG8 , which is a flowchart of the shift control method. The shift control method includes the following steps:

Step S10: In the parallel hybrid first gear mode, the engine speed and actual engine torque of the engine 1 are obtained, and the wheel end torque demand is obtained.

In at least one embodiment of the present application, the engine speed and actual engine torque of the engine 1 are obtained by the engine management system 100. The wheel end torque demand is obtained by looking up the table according to the accelerator pedal and the vehicle speed signal.

Step S11, obtaining the engine torque demand according to the engine speed and the wheel end torque demand.

In at least one embodiment of the present application, the engine torque demand is obtained by looking up the above Table 1. Table 1 is formed in the manner described above and will not be described again.

Step S12: Calculate the actual power of the engine in the first gear of the parallel hybrid according to the actual engine power, and calculate the wheel-end required power according to the wheel-end torque demand.

In at least one embodiment of the present application, the actual engine power can be calculated by the above-described formula 1. The wheel-end required power can be calculated by the above-described formula 2, which will not be described in detail here.

Step S13, comparing the actual engine power and the wheel-end required power, and controlling the working mode of the first motor 2 or the second motor 3 according to the comparison result.

In at least one embodiment of the present application, when the wheel-end power requirement is greater than or equal to the actual engine power, the second motor 3 provides auxiliary power to meet the wheel-end power requirement. When the wheel-end power requirement is less than the actual engine power, the first motor 2 generates electricity to provide voltage to other components of the dual-motor vehicle 1000. When the first motor 2 is working, the first motor torque requirement can be calculated according to the above formula 7.

In at least one embodiment of the present application, the first motor torque demand is calculated by the above formula three, and the second motor torque demand is calculated by the above formula four, which will not be repeated here.

Step S14: When receiving the designated gear shift switching signal, the dual-motor vehicle 1000 operates in the first stage to switch the wheel end torque provided by the engine 1 through the input shaft 8 to the wheel end torque provided by the second motor 3.

In at least one embodiment of the present application, the designated gear shift switch signal instructs the dual-motor vehicle 1000 to switch from the parallel hybrid first gear to the parallel hybrid second gear.

In at least one embodiment of the present application, the input shaft torque decreases in a step-by-step manner with a first step length at a predetermined time, and the second motor torque is controlled to increase in a step-by-step manner with a first step length at a predetermined time. In at least one embodiment of the present application, the predetermined time is 10 milliseconds (ms) to maintain the wheel end torque of the vehicle wheel end 7 unchanged. The change mode of the input shaft torque can be calculated according to the above formula five. The change mode of the second motor torque can be calculated according to the above formula six.

In at least one embodiment of the present application, in the first stage T1 , the brake 4 is controlled to be in an engaged state and the clutch 5 is controlled to be in a disengaged state.

Step S15 : The dual-motor vehicle 1000 operates in the second stage T2 to control the brake 4 to be combined with the sun gear 13 .

In at least one embodiment of the present application, the oil pressure of the brake 4 is controlled to be reduced to a half-engagement point (Kisspoint, KP) so that the brake 4 is engaged with the sun gear 13. The clutch 5 is in a disengaged state.

Step S16: The dual-motor vehicle 1000 operates in the third stage T3, so as to use the first motor 2 to adjust the speed of the engine 1 to the target engine speed in the parallel hybrid second gear.

In at least one embodiment of the present application, in the third stage T3, the dual-motor vehicle 1000 is in the series hybrid mode, that is, the brake 4 and the clutch 5 are both in the disengaged state.

Please refer to FIG. 9 . In at least one embodiment of the present application, step S16 specifically includes the following steps:

Step S161, calculating the target engine speed;

Step S162, calculating the engine power demand according to the second motor torque obtained in the first stage T1;

Step S163, calculating the engine torque requirement according to the engine target speed and the engine power requirement and sending it to the second motor controller 300;

Step S164 , calculating the speed difference between the target engine speed and the current actual engine speed, and calculating the first motor torque demand based on the speed difference based on a proportional integral (PI) control algorithm and sending it to the first motor controller 200 .

In at least one embodiment of the present application, the target engine speed is the engine speed of the parallel hybrid second gear.

In at least one embodiment of the present application, in the current series hybrid mode, the engine power demand includes the second motor demand and the power demand of other components. That is, part of the engine power is provided to the second motor 3, and the other part is provided to other accessories. Since the second motor 3 provides power to the vehicle wheel end 7 at the end of the first stage T1, the vehicle control module 400 can calculate the second motor torque demand based on the wheel end torque demand, the engine target speed can be calculated by the above formula 10, the second motor torque demand can be calculated according to the above formula 8, the engine power demand can be calculated according to the above formula 9, the engine torque demand can be calculated according to the above formula 11, and the first motor torque demand can be calculated according to the above formula 12, which will not be repeated here.

In at least one embodiment of the present application, the first motor torque demand can be calculated according to the above formula twelve, which will not be described in detail here.

Step S17: The dual-motor vehicle 1000 operates in the fourth stage T4 to control the clutch 5 to be in the engaged state.

In at least one embodiment of the present application, the vehicle control module 400 controls the clutch 5 to load the oil pressure (as shown in FIG. 4 ) when detecting that the speed difference between the two ends of the clutch 5 is within 50 revolutions per minute (rpm), thereby realizing that the clutch 5 is in a engaged state.

Step S18 : The dual-motor vehicle 1000 operates in the fifth stage T5 to switch the wheel-end torque provided by the second motor 3 to the wheel-end torque provided by the engine 1 through the input shaft 8 .

In at least one embodiment of the present application, the input shaft torque increases in a step-by-step manner with a second step length at predetermined intervals, and the second motor torque is controlled to increase in a step-by-step manner with a second step length at predetermined intervals. In at least one embodiment of the present application, the predetermined time is 10 milliseconds (ms). The second step length may be the same as or different from the first step length to maintain the wheel end torque of the vehicle wheel end 7 unchanged. At this time, the change mode of the input shaft torque can be calculated according to the above formula fifteen. The change mode of the second motor torque can be calculated according to the above formula sixteen.

In at least one embodiment of the present application, in the first stage T1 , the brake 4 is in a disengaged state, and the clutch 5 is in a engaged state.

The above-mentioned shift control system B and shift method use the second motor 3 to maintain the torque required by the vehicle wheel end 7 when switching from the parallel hybrid first gear to the parallel hybrid second gear, and use the engine 1 to provide the torque required by the vehicle wheel end 7 after the switching is completed, so as to achieve a smooth transition of the wheel end torque during the mode switching process, and have good smoothness. At the same time, the performance requirements for the brake, clutch and other components during the shifting process are reduced, and the service life of the brake, clutch and other components can be improved. At the same time, the complexity of the shifting process of the dual-motor vehicle 1000 is reduced.

Those skilled in the art should recognize that the above embodiments are only used to illustrate the present application and are not intended to be limiting of the present application. As long as they are within the spirit and scope of the present application, appropriate changes and modifications to the above embodiments are within the scope of protection claimed in the present application.

Claims

A shift control method is applied to a dual-motor vehicle; the dual-motor vehicle includes an engine, a first motor, a second motor, a brake, a clutch and a vehicle wheel end, characterized in that the shift control method includes:

When receiving a designated shift switching signal, the dual-motor vehicle switches the wheel-end torque provided by the engine through the input shaft to the wheel-end torque provided by the second motor;

The dual-motor vehicle controls the brake to be combined with the sun gear;

The dual-motor vehicle uses the first motor to adjust the speed of the engine to a target engine speed corresponding to a target gear position;

The dual-motor vehicle controls the clutch to be in an engaged state;

The dual-motor vehicle switches the wheel-end torque provided by the second motor to the wheel-end torque provided by the engine through the input shaft.
The shift control method according to claim 1 is characterized in that the step of switching the wheel end torque provided by the engine through the input shaft to the wheel end torque provided by the second motor in the dual-motor vehicle comprises:

The input shaft torque of the input shaft is controlled to decrease in a stepwise manner with a first step length every predetermined time, and the second motor torque of the second motor is controlled to increase in a stepwise manner with the first step length at the predetermined time to maintain the wheel end torque of the vehicle wheel end unchanged.
The shift control method according to claim 2 is characterized in that the step of the dual-motor vehicle using the first motor to adjust the speed of the engine to the target engine speed corresponding to the target gear position comprises:

Calculating an engine target speed; wherein the engine target speed is the engine speed after the gear shift;

Calculating the engine power demand according to the second motor torque when the input shaft torque is zero;

Calculating an engine torque demand according to the engine target speed and the engine power demand;

The speed difference between the engine target speed and the actual speed of the engine is calculated, and the first motor torque demand is calculated based on the speed difference based on a proportional integral (PI) control algorithm; wherein the first motor torque demand serves as a feedback torque demand, which together with the second motor torque demand adjusts the engine speed to the engine target speed.
The shift control method according to claim 1, characterized in that the shift control method further comprises:

When it is detected that the speed difference between the two ends of the clutch is within 50 revolutions per minute, the clutch is controlled to load oil pressure, thereby achieving the clutch being in a engaged state.
The shift control method according to claim 1 is characterized in that the step of switching the wheel end torque provided by the second motor to the wheel end torque provided by the engine through the input shaft in the dual-motor vehicle comprises:

The input shaft torque of the input shaft is controlled to increase stepwise with a second step size at every predetermined time, and the second motor torque of the second motor is controlled to decrease stepwise with the second step size at the predetermined time to maintain the wheel end torque of the vehicle wheel end unchanged.
The shift control method according to claim 1, characterized in that the designated shift switching signal instructs the dual-motor vehicle to switch from a parallel hybrid first gear to a parallel hybrid second gear; the shift control method further comprises:

In the first gear of the parallel hybrid, obtaining the engine speed and actual engine torque of the engine, and obtaining the wheel end torque demand;

Acquiring an engine torque demand according to the engine speed and the wheel end torque demand;

Calculating the actual power of the engine in the first gear of the parallel hybrid according to the actual torque of the engine, and calculating the required wheel-end power according to the wheel-end torque requirement;

The actual engine power and the wheel-end required power are compared, and the working mode of the first motor or the second motor is controlled according to the comparison result.
The shift control method according to claim 6, characterized in that the shift control method further comprises:

When the wheel end required power is greater than or equal to the actual power of the engine, controlling the second motor to provide auxiliary power to the vehicle wheel end to meet the wheel end required power;

When the wheel end power requirement is less than the actual power of the engine, the first motor is controlled to generate power and provide power to the Other elements of the dual motor vehicle.
The shift control method as described in claim 1 is characterized in that when the dual-motor vehicle uses the first motor to adjust the speed of the engine to the engine target speed corresponding to the target gear, the dual-motor vehicle is in a series hybrid mode.
A gear shift control system comprises a memory and a processor; wherein the processor is used to implement the gear shift control method as described in any one of claims 1 to 8 when executing the computer program code stored in the memory.
A dual-motor vehicle comprises a memory and a processor; wherein the processor can implement the shift control method as claimed in any one of claims 1 to 8 when executing the computer program code stored in the memory.