KR20240061617A - Electric machine control method and device for vehicle - Google Patents

Abstract

This application relates to the technical field of vehicle control, and specifically to methods and devices for controlling electric machines for vehicles. An electric machine control method for a vehicle includes the following steps: obtaining vehicle status information in response to a gear shift signal; determining required total vehicle torque according to the vehicle state information; Depending on the operating parameters of the engine, determining whether to perform electromechanical assistance or not; If confirmed to be performing electromechanical assistance, calculating the required engine torque; and determining the required electromechanical torque for the electromechanical auxiliary output according to the required overall vehicle torque and the required engine torque.

Description

Electrical machine control method and device for vehicle {ELECTRIC MACHINE CONTROL METHOD AND DEVICE FOR VEHICLE}

This application relates to the technical field of vehicle control, and specifically to methods and devices for controlling electric machines for vehicles.

The parallel hybrid power system may include a P0 power system, a P1 power system, a P2 power system, and a P3 power system depending on the location of the electric machine. In the P0 power system, the electric machine is coupled to the engine by a belt transmission mechanism, and the torque of the engine and electric machine is output to the power output shaft by the clutch and gearbox (0). In a P1 power system, the electric machine is mounted between the engine and the gearbox, and the electric machine is not separate from the engine. In a P2 power system, the electric machine is mounted between the engine and the gearbox, but the electric machine is separated from the engine by a clutch. That is, when the clutch is disengaged, the electric device is disconnected from the engine. In the P3 power system, the electric machine is mounted between the gearbox and differential.

Regarding the gear shift control of hybrid vehicles, some existing solutions have been disclosed by calculating the electromechanical compensation torque and using the electric drive torque as power compensation when shifting gears, resulting in deceleration during gear shifting due to power interruptions occurring during gear shifting. It solves a series of problems such as shock, jerk, etc.

In an embodiment of the present application, a method and apparatus for controlling an electric machine for a vehicle are provided. Torque distribution is performed after gear shifting is completed, and assistance is performed using an electric machine to assist the engine to respond quickly to power requirements and effectively reduce the impact of power interruption during gear shifting, improving the drivability and safety of the vehicle. .

According to a first aspect of the present application, a method for controlling an electric machine for a vehicle is disclosed, the method comprising: obtaining vehicle state information in response to a gear shift signal; determining required total vehicle torque according to the vehicle state information; Depending on the operating parameters of the engine, determining whether to perform electromechanical assistance or not; calculating required engine torque when it is confirmed that the electromechanical assistance is to be performed; and determining the required electromechanical torque for the electromechanical auxiliary output according to the required overall vehicle torque and the required engine torque.

In one or more embodiments of the first aspect of the application, optionally, the gear shift signal indicates that the upshift is complete, and the vehicle status information includes accelerator pedal opening information and vehicle speed information, wherein the total vehicle torque required is It is determined based on at least the accelerator pedal opening information and vehicle speed information. Optionally, the operating parameters of the engine include actual engine torque, where it is determined that electromechanical assistance is performed when the actual engine torque is determined to be below a threshold. Optionally, calculating the required engine torque includes calculating the required engine torque based on one or more of engine speed, oxygen sensor signal, or longitudinal deceleration. After the upshift is completed, the required engine torque is calculated as the engine and clutch begin to engage each other. Optionally, when the difference between the required total vehicle torque and the required engine torque is determined to be less than or equal to the maximum electric machine torque, the difference is used as the required electric machine torque and the difference between the required total vehicle torque and the required engine torque. When is determined to be greater than the maximum electric machine torque, the difference is used as the required engine torque, and the required engine torque is updated to the difference between the total required vehicle torque and the maximum electric machine torque. The electrical machine is a P0 electrical machine.

According to a second aspect of the present application, a controller for an electric machine is disclosed. The controller includes a processor and a memory, where the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the processor is capable of performing one or more steps in the method according to the first aspect of the present application.

According to a third aspect of the present application, a computer program product for controlling an electric machine is provided. When computer program instructions are executed by a processor, the processor may perform one or more steps in the method according to the first aspect of the present application.

According to a fourth aspect of the present application, a computer-readable storage medium for controlling an electric machine is provided. When the instructions are executed by a processor, the processor may perform one or more steps in the method according to the first aspect of the present application.

The principles, features and advantages of the present invention will be more fully understood from the following detailed description of certain exemplary embodiments with reference to the accompanying drawings.
1 is a schematic architecture diagram of a hybrid power system according to an embodiment of the present application.
Figure 2 is a schematic flowchart of an electric machine control method for a hybrid vehicle according to an embodiment of the present application.
Figure 3 is a schematic flowchart of torque distribution calculation for a hybrid vehicle according to an embodiment of the present application.
4 is a schematic diagram of the torque of a hybrid vehicle with a P0 configuration during gear shifting according to an embodiment of the present application.
Figure 5 is a schematic diagram of a functional unit of an electromechanical control device for a hybrid vehicle according to an embodiment of the present application.

In order to solve the technical problems of the present invention and make the technical solutions and beneficial technical effects more clear, the present invention will be described in more detail with reference to the attached drawings and a plurality of embodiments. It should be understood that the specific examples described herein are only used to illustrate the present invention and are not used to define the protection scope of the present invention. Those skilled in the art will readily recognize that the same principles can be applied to other hybrid power systems that are different from the single-electromechanical hybrid power system described herein, and that the same or similar principles described above can be implemented therein. Any such changes do not depart from the spirit and scope of the present application.

1 is a schematic architecture diagram of a hybrid power system according to an embodiment of the present application. For brevity, Figure 1 shows only some components of the vehicle's hybrid power system. As shown in FIG. 1, the hybrid power system of the vehicle includes an engine 10, and the engine 10 may be an internal combustion engine that uses gasoline, diesel, natural gas, etc. as fuel. The clutch 14 is disposed between the engine 10 and the gearbox 16 and is used to perform or block the transmission of power of the engine 10. The power output of the clutch 14 is transmitted to the transmission shaft by the gearbox 16, and the transmission shaft distributes torque to the wheels 30 by a differential (not shown). The hybrid power system of this embodiment further includes an electric machine 12, and the electric machine 12 and the engine 10 are configured according to the P0 architecture. Electrical machine 12 may consist of a motor and/or generator. The electrical machine 12 may be a belt starter generator (BSG). The electric machine 12 is operably connected to the crankshaft of the engine 10 by means of a transmission belt, so as to effect torque transmission between the engine 10 and the electric machine 12 by means of the transmission belt. Electrical machine 12 is electrically connected to battery 18 and other electrical systems within the vehicle.

Typically, vehicles provided with a P0 electric machine may be used to assist in starting and stopping the engine, recovering braking energy, and assisting with acceleration. The electric machine 12 may assist in starting the engine 10 during startup of the engine 10 or may be configured to perform acceleration assistance by providing additional torque to the engine 10 when the vehicle is moving. . The electric machine 12 can additionally receive torque from the engine 10 and charge the battery 18 as a generator. In other embodiments, engine 10 and electric machine 12 may be configured in different ways. In one example, engine 10 and electric machine 12 are configured according to the P1 architecture. The P1 electric machine is placed as an integrated starter generator (ISG) at the rear end of the engine and is connected to the crankshaft. The P1 electric machine can also be used to help start and stop the engine, recover braking energy, and assist with acceleration.

In one or more embodiments of the invention, torque distribution between engine 10 and electric machine 12 is performed after gear shifting is completed. Assistance is performed using the electric machine 12 to assist the engine 10 to quickly respond to power requirements after the gear shift is completed. For vehicles equipped with a manual transmission (MT) or automatic mechanical transmission (AMT), a power interruption occurs when the vehicle performs a gear shifting operation. In operating conditions such as high load, uphill, plateau, etc., gear shifting operation may result in an undue decrease in vehicle speed and traction, which not only affects vehicle drivability but may also cause safety hazards. In one example, for a P0 power system equipped with an MT or AMT, to improve the speed of response of the engine after a gear shift is completed, when it is determined that the engine cannot provide sufficient torque, the fast response characteristics of the electric machine are used. It outputs auxiliary torque after power engagement. Currently, the technical solution of using the P0 electric machine to perform torque compensation after gear shifting is not provided in the prior art.

Continuing with reference to FIG. 1 , the hybrid power system of the vehicle further includes a controller 20 . Controller 20 communicates with the vehicle control unit (VCU), engine management system (EMS), motor control unit (MCU), battery management system (BMS), and transmission control unit (TCU) via a controller area network (CAN). can do. Controller 20 may receive a vehicle speed signal from a vehicle speed sensor, receive an accelerator pedal opening signal from an accelerator pedal sensor, and determine the required overall vehicle torque, for example, via a table lookup. The controller 20 may additionally receive the charging state of the battery from the battery management system. Controller 20 may further receive engine torque and speed signals from engine 10, electric machine torque and speed signals from electric machine 12, and current gear signals from gearbox 16. The controller 20 is further configured to transmit the required engine torque to the engine 10, transmit the required electric machine torque to the electric machine 12, and transmit upshift or downshift commands to the transmission 16. It can be. Controller 20 may be part of a vehicle control unit (VCU) or engine electronic control unit (ECU).

Operations performed in one or more embodiments of the present application may be implemented by various program modules implemented as computer code within controller 20. The controller 20 is configured to select the vehicle drive sources between the engine 10 and the electric machine 12 and the torque distribution between them. Controller 20 may be further configured to transmit signals to electrical machine 12 to cause electrical machine 12 to operate as a motor or generator. In one example, control logic executed by controller 20 may distribute the required engine torque and the required electromechanical torque according to information obtained after the gear shift is completed and the effects of power interruptions caused by the gear shift process. Auxiliary output of the electric machine 12 may be performed to reduce .

The hardware configuration of the controller 20 may include a processor and memory. Processors and memory communicate with each other by other methods, such as buses or wireless transmission. Memory is used to store instructions. The processor is used to execute instructions stored by memory. The memory stores computer program instructions, and when the computer program instructions are executed by a processor, the processor may perform one or more steps of the methods described herein. The processor may be a central processing unit (CPU), digital signal processor (DSP), application-specific integrated circuit (ASIC), or field-programmable gate array (FPGA). The memory may include read only memory (ROM) and random access memory (RAM) and may store executable instructions used by the controller to control the vehicle's engine, electrical machinery, or other components. The processor may call program codes stored in memory to perform a plurality of steps of the above-described vehicle control method.

Figure 2 is a schematic flowchart of an electric machine control method for a hybrid vehicle according to an embodiment of the present application. As shown in FIG. 2, the process of the method may include steps 210 to 250.

In step 210, vehicle state information is obtained in response to the gear shift signal. The gear shift signal may be a signal indicating that gear shift is complete. In one example, the gear shift signal may be a signal indicating that an upshift is complete. Gear information may be obtained from the transmission control unit. When it is determined that the current gear information has changed, it may be determined that a gear upshift or downshift has occurred. Vehicle status information may include accelerator pedal opening information and vehicle speed information obtained from each sensor.

In step 220, the total required vehicle torque is determined according to vehicle state information. When the vehicle state information includes accelerator pedal opening information and vehicle speed information, the required total vehicle torque may be determined at least according to the accelerator pedal opening information and vehicle speed information (eg, by a table lookup). Those skilled in the art will appreciate that the required overall vehicle torque may also be obtained by other means.

At step 230, whether to perform electromechanical assistance is determined depending on the operating parameters of the engine. The operating parameters of the engine may include actual engine torque, where it is determined that electromechanical assistance is performed when the actual engine torque is determined to be below a threshold. The operating parameters of the engine may also include actual engine speed, where it is determined that electromechanical assistance is performed when the actual engine speed is determined to be below a threshold. The actual torque and actual speed of the engine can be obtained from the engine ECU.

At step 240, the required engine torque is calculated upon confirmation that electromechanical assistance is performed. The required engine torque may be calculated based on one or more of engine speed, oxygen sensor signals, or longitudinal deceleration. After the upshift is complete, the required engine torque can be calculated when the engine and clutch begin to engage each other. In this embodiment, factors such as engine speed, oxygen sensor signal, longitudinal deceleration, etc. are taken into consideration and appropriate torque is distributed to the engine. For example, the torque distributed to the engine may be directly proportional to engine speed and oxygen content, and inversely proportional to longitudinal deceleration.

At step 250, the required electromechanical torque for the electromechanical auxiliary output is determined according to the required overall vehicle torque and the required engine torque. When the difference between the required total vehicle torque and the required engine torque is determined to be less than the maximum electric machine torque, the difference is used as the required electric machine torque, and the difference between the required total vehicle torque and the required engine torque is used as the maximum electric machine torque. When determined to be greater than the machine torque, the difference is used as the required engine torque, and the required engine torque is updated to the difference between the required total vehicle torque and the maximum electric machine torque. The maximum electromechanical torque can be calculated according to electromechanical speed information and electromechanical power information.

Figure 3 is a schematic flowchart of torque distribution calculation for a hybrid vehicle according to an embodiment of the present application.

As shown in Figure 3, at step 301, the engine speed is obtained from the engine ECU, the oxygen content is obtained from the oxygen sensor, and the longitudinal deceleration is obtained from the vehicle speed sensor.

In step 302, the engine torque distribution coefficient ( ) is calculated, and the engine torque distribution coefficient ( )'s numerical range is [0, 1], and the engine torque distribution coefficient ( ) is directly proportional to engine speed and oxygen content, and inversely proportional to longitudinal deceleration. In some examples, the engine torque distribution coefficient ( ) can be determined depending on one of engine speed, oxygen content, and longitudinal deceleration. In this embodiment, the engine torque distribution coefficient ( ) is calculated according to engine speed, oxygen content and longitudinal deceleration, allocating a more reasonable torque increase process to the engine. Engine torque distribution coefficient ( ) can be calculated by using the formula below.

In the above formula, a , b , c , and d are coefficients with value ranges of (0, 1) and adjusted according to different application policies. In one example, d is 22%. In another example, a is greater than 50%. n _eng is the engine speed, which can be obtained from the crankshaft speed sensor. n _engmax is the maximum engine speed and is an engine design parameter. p _lambda is the oxygen content, which can be obtained from an oxygen sensor and is in percentage units. α _dec is the longitudinal deceleration of the vehicle and can be obtained by performing a derivation on the vehicle speed obtained from the vehicle speed sensor. α _decmax is the maximum deceleration when no braking is performed on the vehicle and can be obtained by performing the test at maximum inclination (e.g. 10%) when the vehicle is fully loaded, or calculated depending on the force application situation under specific operating conditions. It can be.

At step 303, the electromechanical torque distribution coefficient ( ) was calculated. Silver 1 - Same as

At step 304, it is determined whether the electromechanical torque is distributed. T _mreq is less than or equal to the maximum electromechanical torque (T _{m_max} ). The electromechanical torque is It is equal to multiplying by T _DrvReq . T _DrvReq is the total vehicle torque required. If it is determined that the electric machine torque (T _mreq ) is less than or equal to the maximum electric machine torque (T _{m_max} ), step 305 is performed, otherwise step 306 is performed.

At step 305, *T _DrvReq is assigned to the required engine torque (T _{ereq_Ini} ), (1- )*T _DrvReq is assigned to the required electromechanical torque (T _{mreq_Ini} ).

At step 306, T _DrvReq -T _{m_max} is assigned to the required engine torque (T _{ereq_Ini} ), and T _{m_max} is assigned to the required electric machine torque (T _{mReq_Ini} ).

In this embodiment, after upshifting, the engine torque distribution coefficient is calculated according to the operating conditions of the engine, and the vehicle requirements are distributed to the engine and the electric machine, effectively reducing the influence caused by power interruption during gear shifting.

Individual steps in the flowcharts of FIGS. 2 and 3 may be implemented by computer program instructions. The foregoing computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing device constituting the machine, causing the processor of the computer or other programmable data processing device to execute the foregoing instructions. . In some alternative implementations, the steps depicted in the blocks may not occur in the order depicted by the flow diagram. For example, two blocks shown in succession may be performed substantially simultaneously or in a different order.

4 is a schematic diagram of the torque of a hybrid vehicle with a P0 configuration during gear shifting according to an embodiment of the present application. During gear shifting of MT or AMT, due to the interruption of engine power, the vehicle is prone to jerk, thereby affecting the comfort of the driver or passengers. In order to alleviate the above problem of power cutoff in gear shifting, according to the electric machine control method and device for a hybrid vehicle of the embodiment, the P0 electric machine is called to output torque after completion of gear shifting, so that the torque output by the engine Increases response speed.

As shown in Figure 4, the horizontal axis represents time. Sg represents the gear state. Sc represents the clutch state. Te and Tm represent engine torque output and electromechanical torque output, respectively.

From time T0 to time T1, the transmission control unit receives a gear shift signal. Gear shifting begins and the clutch is disengaged. The clutch state changes from an engaged state to a disengaged state. Engine torque (Te) begins to drop. The electromechanical torque (Tm) remains unchanged, for example zero. At time T1, the gear shift is completed, and the gear state Sg rises from the low gear to the high gear. The motor control unit of the hybrid vehicle may obtain accelerator pedal opening information and vehicle speed information in response to the gear upshift completion signal of the transmission control unit, and determine the required overall vehicle torque according to the information.

From time T1 to time T2, the transmission upshift is completed and the clutch remains disengaged. The engine torque (Te) continues to drop, and the electromechanical torque (Tm) remains unchanged.

Beginning at time T2, the clutch begins to engage. From time T2 to time T4, the clutch state Sc begins to transition from the disengaged state to the engaged state. From time T2 to time T3, the engine torque Te continues to drop, and the electric machine torque Tm remains unchanged. Starting from time T2, it can be decided, depending on the operating parameters of the engine, whether to perform electromechanical assistance. The operating parameters of the engine include actual engine torque. When it is determined that the actual engine torque is below the threshold, it is determined to perform electromechanical assistance.

Starting from time T3, when it is confirmed that electromechanical assistance is performed, the required engine torque is calculated. Calculating the required engine torque includes calculating the required engine torque based on one or more of engine speed, oxygen sensor signal, or longitudinal deceleration. When the difference between the required total vehicle torque and the required engine torque is determined to be less than the maximum electric machine torque, the difference is used as the required electric machine torque, and the difference between the required total vehicle torque and the required engine torque is used as the maximum electric machine torque. When determined to be greater than the machine torque, the difference is used as the required engine torque, and the required engine torque is updated to the difference between the required total vehicle torque and the maximum electric machine torque. From time T3, for the engine and electric machine according to the distributed torque, the engine begins to increase the torque, and the electric machine begins to perform gear shifting assistance.

At time T4, clutch engagement is completed, and the clutch state Sc changes to the engaged state. From time T3 to time T5, the engine and electric machine provide the required total vehicle torque from the onset of torque to the completion of torque rise. As can be seen from Figure 4, engine torque ramp-up and electromechanical assistance start at time T3, the clutch begins to engage at time T2, and completes engagement at time T4. Electromechanical assistance is initiated during clutch engagement, effectively mitigating the effects of power interruption. However, a person skilled in the art will understand that engine torque ramp-up and electromechanical assistance can also start at time T4.

At time T6, when it is detected that the accelerator pedal condition is stable, the electromechanical assistance begins to end. At this point, the engine begins to build torque again. At time T7, the electromechanical assistance is completely terminated and the entire required vehicle torque is fully provided by the engine. Here, when it is determined that the accelerator pedal opening has been maintained within a certain range for a period exceeding a predetermined time, the accelerator pedal condition is determined to be stable, and the electromechanical assistance shutdown process is initiated.

In embodiments of the present invention, a power compensation control method is formulated to eliminate or alleviate the problem of power cut-off in gear shifting of an AMT utilizing an electric machine.

Figure 5 is a schematic diagram of a functional unit of an electromechanical control device for a hybrid vehicle according to an embodiment of the present application. The electromechanical control device 500 is used to implement the functionality of the controller 20 shown in Figure 1 and is configured to perform one or more steps in the method shown in Figure 2. The control device 500 includes a required overall vehicle torque determination unit 510, an electromechanical auxiliary determination unit 520, and a torque distribution calculation unit 530.

The required overall vehicle torque determination unit 510 obtains vehicle state information in response to the gear shift signal and determines the required overall vehicle torque according to the vehicle state information. The required total vehicle torque determination unit 510 may be configured to determine the required total vehicle torque according to the accelerator pedal opening information and vehicle speed information.

The electromechanical assistance decision unit 520 determines whether to perform electromechanical assistance, depending on the operating parameters of the engine. The electromechanical assistance determination unit 520 may be configured to determine to perform electromechanical assistance when the actual engine torque is determined to be below a threshold.

When it is determined to perform electromechanical assistance, the torque distribution calculation unit 530 calculates the required engine torque and calculates the required electromechanical torque for the electromechanical assistance output according to the required overall vehicle torque and the required engine torque. decide Torque distribution calculation unit 530 may calculate required engine torque based on one or more of engine speed, oxygen sensor signal, or longitudinal deceleration. The torque distribution calculation unit 530 further determines that the difference between the required overall vehicle torque and the required engine torque is less than or equal to the maximum electric machine torque, using the difference as the required overall machine torque, and When it is determined that the difference between the torque and the required engine torque is greater than the maximum electric machine torque, the difference is used as the required engine torque, and the required engine torque is used as the difference between the required total vehicle torque and the maximum electric machine torque. Can be configured to update.

One or more embodiments and various examples above may be implemented in whole or in part by software, hardware, firmware, or a combination thereof. When implemented using software, the embodiments may be implemented in whole or in part in the form of a computer program product. A computer program product includes one or more computer instructions. When computer program instructions are loaded and executed on a computer, processes or functions according to embodiments of the present application are implemented in whole or in part. The computer may be a general-purpose computer, special-purpose computer, computer network, or other programmable device. Computer instructions may be stored on a computer-readable storage medium or transmitted as a computer program product from a network server to another computer, either wired or wirelessly.

In the embodiments of the present application, the described functional units and devices are merely exemplary. The division of functional units is only a logical function division, and other division methods may exist during the implementation process. Multiple units and devices may be physically separate, distributed across network units, and combined or integrated into other systems. The above examples are merely specific examples of the present application. Any changes or replacements that a person skilled in the art may consider according to the specific embodiments provided in this application shall fall within the protection scope of this application.

The above-described embodiments are only specific embodiments of the present application, and the protection scope of the present application is not limited thereto. A person skilled in the art may consider other feasible changes or replacements according to the technical content and teachings disclosed in this application, and such changes or replacements fall within the protection scope of this application. The embodiments of the present application as well as the features of the embodiments may be combined with each other in appropriate circumstances. The scope of protection of this application depends on the claims.

Claims (10)

An electromechanical control method for a vehicle, comprising:
Obtaining vehicle status information in response to a gear shift signal;
determining required overall vehicle torque according to the vehicle state information;
Depending on the operating parameters of the engine, determining whether to perform electromechanical assistance or not;
calculating required engine torque if the electromechanical assistance is confirmed to be performing; and
and determining a required electric machine torque for an electric machine auxiliary output according to the required overall vehicle torque and the required engine torque. According to paragraph 1,
The gear shift signal indicates that the upshift is complete,
The vehicle status information includes accelerator pedal opening information and vehicle speed information,
The method of claim 1 , wherein the required total vehicle torque is determined according to at least the accelerator pedal opening information and the vehicle speed information. According to paragraph 2,
The operating parameters of the engine include actual engine torque,
and wherein it is determined to perform the electromechanical assistance when it is determined that the actual engine torque is below a threshold. According to paragraph 1,
The method of claim 1 , wherein calculating the required engine torque comprises calculating the required engine torque according to one or more of: engine speed, oxygen sensor signal, or longitudinal deceleration. According to paragraph 1,
After the upshift is completed, the required engine torque is calculated when the engine and clutch begin to engage each other. According to paragraph 1,
when it is determined that the difference between the required overall vehicle torque and the required engine torque is less than or equal to the maximum electric machine torque, using the difference as the required electric machine torque;
When it is determined that the difference between the required overall vehicle torque and the required engine torque is greater than the maximum electric machine torque, the difference is used as the required engine torque, and the required engine torque is the required overall vehicle torque. and the maximum electric machine torque. According to paragraph 1,
The method of claim 1, wherein the electrical machine is a P0 electrical machine. 1. A controller for an electric machine, comprising a processor and a memory, wherein the memory stores computer program instructions, and when the computer program instructions are executed by the processor, the processor performs the operations of claims 1 to 7. A controller capable of performing the method according to any one of the above. A computer program product comprising computer program instructions, wherein when the computer program instructions are executed by a processor, the processor is capable of performing the method according to any one of claims 1 to 7. A computer-readable storage medium storing instructions, wherein when the instructions are executed by a processor, the processor is capable of performing the method according to any one of claims 1 to 7. media.