CN120171507B

CN120171507B - Hybrid Electric Vehicle Mode Control Method

Info

Publication number: CN120171507B
Application number: CN202510659702.9A
Authority: CN
Inventors: 宋华; 陈韶庆; 吴恭敏; 李雅军; 庞艳红
Original assignee: Anhui Jianghuai Automobile Group Corp
Current assignee: Anhui Jianghuai Automobile Group Corp
Priority date: 2025-05-21
Filing date: 2025-05-21
Publication date: 2025-09-02
Anticipated expiration: 2045-05-21
Also published as: CN120171507A

Abstract

The present invention discloses a hybrid vehicle mode control method. Targeted at a P2.5+P4 hybrid vehicle architecture with a four-speed gearbox, the method makes targeted designs for the control of engine starting scenarios and hybrid mode operating conditions. The method mainly includes: presetting a mandatory power generation zone and a priority power generation zone of a battery; if the power level is in the mandatory power generation zone, the engine is started to conserve power; if the power level is in the priority power generation zone and the vehicle is traveling at a predetermined speed, the engine is started to generate power; and when the vehicle is traveling normally in pure electric mode, if the battery or motor is under heavy workload for a long time, the engine is started accordingly to enter a series mode or a parallel mode respectively; in addition, based on the above architecture, the present invention further proposes executing different mode judgment mechanisms according to the driver's operating intentions, so that the vehicle can reliably and accurately respond to the driver's needs, thereby providing a more ideal solution for the mode control of hybrid vehicles with the above architecture.

Description

Mode control method for hybrid electric vehicle

Technical Field

The invention relates to the technical field of hybrid electric vehicles, in particular to a hybrid mode management control of a P2.5+P4 hybrid architecture, and specifically relates to a hybrid electric vehicle mode management control method.

Background

In the industry, the P2.5 is used as a parallel hybrid electric vehicle route, the P2.5 motor can realize an engine start-stop function and a parallel power assisting function (power assisting or power generating when the engine is directly driven), and can realize a series connection function after being matched with a P4 motor (wheel direct driving motor layout). However, there is no relatively ideal solution in the industry for achieving reliable and stable mode control under the architecture p2.5+p4, especially engine start and related mode switching.

Disclosure of Invention

In view of the foregoing, the present invention is directed to a method for controlling a mode of a hybrid vehicle, so as to solve the above-mentioned technical problems.

The technical scheme adopted by the invention is as follows:

The invention provides a mode control method of a hybrid electric vehicle, which comprises a whole vehicle controller, a rear motor controller, a gearbox controller, a front motor controller and an engine controller, wherein the hybrid electric vehicle is provided with a four-gear gearbox with four clutches, and the mode control method comprises the following steps:

pre-configuring a battery power partition, wherein the battery power partition at least comprises a forced power generation area and a preferential power generation area;

If the SOC is detected to be in the priority power generation area and the vehicle runs at a set speed, starting the engine to generate power;

when the vehicle runs normally in the pure electric mode, if the duration of the battery discharging working condition is detected to be longer than a first set duration, the engine is started to enter a series mode, or if the duration of the motor operating working condition is detected to be longer than a second set duration, the engine is started to enter a parallel mode;

The method comprises the steps of executing different mode judging mechanisms according to the operation intention of a driver, starting an engine to enter a parallel mode if a full accelerator acceleration condition is detected when the vehicle runs normally, starting the engine to enter a series mode if the vehicle is detected to park in a P gear and an accelerator pedal is stepped down or a user trigger is received to enter an in-situ power-up function, starting the engine to enter the series mode if the vehicle is detected to park in a D gear, starting the engine if a brake pedal is detected to be stepped down and is switched to the accelerator pedal to be stepped down, and switching from the series mode to the parallel mode after the brake pedal is released.

In at least one possible implementation, the starting the engine into the series mode includes:

After the engine is started in the pure electric rear-drive mode, the whole vehicle controller sends a serial mode requirement to the gearbox controller;

The first clutch is controlled to be closed by the gearbox controller, the front motor controller is switched to a torque mode, and a pre-calibrated torque is applied to enable the output rotating speed of the engine controller to reach a preset rotating speed;

the engine controller triggers oil injection ignition, and after the engine outputs positive torque, the front motor controller is switched to a rotating speed mode to adjust the economic working point of the engine, and simultaneously negative torque is applied to enable the vehicle to be switched from a pure electric rear drive mode to a series mode.

In at least one possible implementation manner, the control method further comprises the step of distributing torque to the engine, the front motor and the rear motor according to the current vehicle speed, the SOC, the accelerator opening and the whole vehicle state if the front motor controller is switched from the rotating speed mode to the torque mode.

In at least one possible implementation manner, the control method further comprises a target mode requirement decision mechanism:

After the rear motor controller, the gearbox controller, the front motor controller and the engine controller all feed back the fault-free state, the capacities of the current series mode and the parallel mode are calculated according to the available power of the current battery, the available power of the front motor, the available power of the engine and the available power of the rear motor respectively, and the formula is as follows:

Series mode capability = { [ battery available power + (engine available power, front motor available power) _min ], rear motor available power } _min;

Parallel mode capability = engine available power + [ battery available power, (front motor available power + rear motor available power) ] _min;

The vehicle controller judges a target mode demand according to the obtained serial mode capacity, parallel mode capacity and wheel end demand torque, wherein the target mode demand is a parallel mode entering if the current parallel mode capacity is larger than the serial mode capacity and the wheel end demand torque is larger than the serial mode capacity, and the target mode demand is a serial mode entering if the current serial mode capacity is larger than the parallel mode capacity and the wheel end demand torque is larger than the parallel mode capacity.

In at least one possible implementation manner, the control method further includes:

Before switching to the parallel mode, judging whether the current vehicle speed is greater than a preset switching vehicle speed threshold value;

if yes, calculating to obtain a minimum torque value in a parallel mode according to the current vehicle speed, the available power of the battery, the current SOC and the speed ratio of the preselected gear;

and if the wheel end required torque is greater than the minimum torque value, allowing to enter a parallel mode.

In at least one possible implementation manner, the switching speed threshold value is obtained according to the engine speed or a gear shift line based on a gearbox, and the switching speed threshold value is regulated down if the vehicle is currently under a sudden acceleration working condition.

In the process that the vehicles are in series driving, the gearbox controller calculates the current relative optimal preselected gear in real time according to the current speed, the opening degree of an accelerator and the rotating speed of an engine;

Before the whole vehicle controller sends a switching request of a parallel mode to the gearbox controller, regulating the speed of a front motor according to the speed ratio of the preselected gear, the current speed and the rotating speed of a front shaft output shaft of the vehicle;

after receiving an instruction for triggering the parallel mode to start, the gearbox controller controls the clutch corresponding to the preselected gear to be closed;

After determining that the clutch is closed, the gearbox controller updates the current actual gear to the corresponding parallel gear;

And the whole vehicle controller completes switching from a series mode to a parallel mode.

In at least one possible implementation, if the preselected gear is changed, the whole vehicle controller carries out speed regulation again according to the changed preselected gear.

In at least one possible implementation manner, the step of adjusting the speed of the front motor includes:

in the speed regulation process, the whole vehicle controller sends an oil pre-filling instruction to the gearbox controller;

and the gearbox controller combines the current preselected gear, charges oil to the corresponding clutch until the clutch reaches a preset half-combining point.

Aiming at the architecture of the hybrid electric vehicle with the P2.5+P4 of the four-gear gearbox, the invention carries out targeted design on the control of the engine starting scene and the working condition of the hybrid mode, and mainly comprises the following steps of presetting a forced power generation area and a priority power generation area of a battery; the invention further provides a method for executing different mode judging mechanisms according to the operation intention of a driver on the basis of the framework, so that the vehicle can reliably and accurately respond to the requirement of the driver to enter a parallel mode and a serial mode or realize the switching of the serial-parallel mode. Furthermore, the invention provides detailed implementation references for the process and the details related to the mode switching, and provides an ideal solution for the mode control of the P2.5+P4 architecture hybrid vehicle.

Drawings

For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings, in which:

fig. 1 is a schematic diagram of a mode control method of a hybrid electric vehicle according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

The invention provides an embodiment of a mode control method of a hybrid electric vehicle, in particular to a hybrid electric vehicle adopting a P2.5+P4 architecture, wherein control units related to the architecture can be referred to as a VCU whole vehicle controller, an MCU rear motor controller (namely, a P4 motor controller), a TCU gearbox controller, a GCU front motor controller (namely, a P2.5 motor controller), an SOC battery electric quantity, a BMS battery management system and an ECU engine controller.

In some preferred embodiments, the present invention also contemplates the deployment of a multi-speed transmission, which may be a four-speed AT transmission in particular, so that the vehicle can double as a power economy and has rich driving modes.

In terms of development, through the cooperation control of the four clutches A, B, C, D of the four-gear gearbox, the control of two gears of a motor and four gears of an engine can be realized, so that the vehicle is provided with pure electric rear drive, pure electric front drive, pure electric four drive, serial, parallel power generation, parallel power assistance and the like. The GCU can execute a driving function on a front shaft through closing a clutch C or D to realize pure electric four-drive or pure electric precursor, can drag an engine to generate electricity through closing a clutch A and adjust the economy and power point of the engine so as to realize vehicle series connection, and after the vehicle series connection is started, the clutch A is kept closed, meanwhile, the front shaft is closed to drive the clutch B or C or D to realize direct engine drive, and the vehicle series connection can enter a parallel state (AC-1 gear, AD-2 gear, AB-3 gear and CD-4 gear) when all the four clutches are disconnected, and the vehicle series connection is pure electric rear drive.

For the mode control method proposed in this example, as shown in fig. 1, the following implementation references are given here:

Step S1, pre-configuring battery power partitions, wherein the battery power partitions at least comprise a forced power generation area and a preferential power generation area;

In actual operation, the battery power partition may be preconfigured, that is, the VCU partitions the battery power SOC according to the battery power sent by the BMS and the current environmental temperature and altitude information, and may specifically be divided into a forced power generation area, a preferential power generation area, and the like, which may also involve a balance area, a preferential power consumption area, and a forced power consumption area in other embodiments, which are not limited in the present invention. The forced power generation region refers to the forced start of the engine to supplement power for the battery when the electric quantity of the battery is too low, and the preferential power generation region refers to the fact that the engine is easier to start in the SOC region and can supplement power for the battery or be used for driving a motor.

It can be further expanded that several energy modes can be preset for the control method provided by the invention, for example:

And in the pure electric priority mode, in order to ensure the driving experience of a user, the engine is generally difficult to start, and the mode can be started only when the discharge power of the battery or the capacity of the motor cannot meet the power requirement of the front wheel end, or the electric quantity of the battery falls below the priority power generation area, or the engine is started due to the requirement of certain parts of the vehicle, and the power-saving SOC cannot be modified in the mode.

The fuel priority mode is to keep electricity and balance SOC preferentially, and the torque required by the wheel end is larger than the minimum torque required for starting the engine (the torque is smaller in the mode), the engine is started when the adjustment is met, and the electricity keeping SOC can not be modified in the mode.

And in the forced pure electric mode, the engine is forbidden to be started until the electric quantity of the whole vehicle is reduced to be extremely low (which can be determined according to a pre-calibrated lower limit threshold), the vehicle automatically goes to the pure electric priority, and the engine is forced to be started for supplementing electricity.

And in the intelligent mode, the electricity-keeping SOC point set by the user can be received to solve the electricity consumption anxiety based on the angle of the user.

Step S2, if the SOC is detected to be in the forced power generation area, starting the engine to keep electricity until the electricity is supplemented to the priority power generation area, if the SOC is detected to be in the priority power generation area and the vehicle runs at a set speed (the vehicle can be controlled to run at a preset low speed value to keep pure electricity, and the aim of the set speed is to ensure the driving feeling of a user), starting the engine to generate electricity;

Step S3, when the vehicle runs normally in the pure mode, if the duration of the battery discharging working condition is detected to be longer than a first set duration, starting the engine to enter a series mode, or if the duration of the motor operating working condition is detected to be longer than a second set duration, starting the engine to enter a parallel mode;

Specifically, when the vehicle runs normally only (mainly in a pure electric rear-drive mode), if the battery is detected to be in a higher load discharge state for a long time, that is, the available discharge power of the battery may jump, the available power generation power of the battery cannot meet the wheel end driving power of a driver when the driver runs at a constant speed at the current speed, so that the engine is required to start to enter into series connection, and the power is supplemented for the wheel end driving. For the development, the engine is started in a pure electric drive mode, the VCU sends a target mode to the TCU in series, the TCU closes the clutch A, the GCU is rigidly connected with the ECU at the moment, the GCU is switched to a torque mode, a certain torque (a calibration quantity) is applied to enable the rotation speed of the ECU to reach a specified rotation speed, the ECU is used for fuel injection and ignition, the GCU is switched to a rotation speed mode to regulate the economic point of the engine after the engine outputs positive torque, a negative torque is applied, and the actual mode of the whole vehicle is switched from the pure electric drive mode to the series mode to supply power for the battery.

Correspondingly, when the vehicle runs normally in pure electricity, if the motor is detected to be in a higher load working state for a long time, namely the motor is likely to have motor power reduction due to over-temperature and other problems, the current wheel end driving power of the vehicle running continuously at a constant speed cannot be met, the engine is required to start to enter parallel connection, the engine participates in driving, the vehicle is converted into direct engine driving or parallel four-wheel driving (the engine and the P4 motor are simultaneously driven), and regarding the four-wheel driving mode, because the mode provides reliable four-wheel driving capability based on the mixed driving architecture of the P2.5+P4, the vehicle can enter the pure four-wheel driving mode from pure rear-wheel driving or enter the low-speed parallel four-wheel driving mode when a user selects an off-road mode.

Next, step S4, execute the following mode judgment mechanism according to the operation intention of the driver:

when the vehicle runs normally in pure electricity, if the full accelerator overtaking of the driver is detected, the vehicle starts the engine to enter parallel connection, and the vehicle is converted into four-wheel drive in parallel connection so as to improve the dynamic property of the vehicle;

if the vehicle is detected to be in P gear parking and the driver steps on the accelerator in situ, or the user receiving MP4 feedback triggers to enter an in situ power supply function, the engine is started to enter a series connection to supply power to the vehicle;

If the vehicle is in a preset vehicle ejection mode, namely, the vehicle is in an ejection mode by stepping on a brake pedal under D gear and switching to an accelerator pedal to enter the ejection mode, the engine is started at the moment, and after a user releases the brake pedal, the vehicle can quickly enter parallel connection from serial connection, so that the whole vehicle has the maximum acceleration capability.

In addition, when the vehicle is in a low-temperature environment, the vehicle is started, and then the air conditioner is turned on to heat the vehicle, and the engine starts the heating heat management water pump to heat the passenger compartment. The present invention is not described and limited in detail, but may specifically be described as to a decision to enter a series mode or a parallel mode, and may further include the following procedures:

firstly, judging whether the series connection or the parallel connection is allowed or not according to GCU, MCU, TCU and the fault state of the engine, secondly, because of the characteristics of the P2.5+P4 architecture in the embodiment, if the speed of the vehicle is too low during the parallel connection, the engine speed can be pulled back to be very low due to the resistance of the wheel end, so that the engine is flameout, and the parallel connection condition is entered, and at least the current speed is required to meet the preset speed value.

The capabilities of the current series and parallel modes (i.e., available drive power in series/parallel) are calculated from the current battery capability (available power), GCU capability, engine capability, and MCU capability, as follows:

serial capability = { [ battery capability + (engine capability, GCU capability) _min ], MCU capability } _min

Parallel capability = engine capability + [ battery capability, (GCU capability + MCU capability) ] _min

The VCU judges the actual series or parallel connection requirement according to the current series and parallel connection capability and the required torque of the wheel end, wherein if the current parallel connection capability is larger than the series connection capability and the required torque of the wheel end is larger than the series connection capability, the VCU requirement enters the parallel connection, and the same series connection can be also realized, and the description is omitted herein. If the series and parallel connection capacities are large (i.e. the difference between the series and parallel connection capacities is not large), the judging mode is only effective when the wheel end required torque is large, and then the series or parallel connection mode is decided based on the current series and parallel connection capacities when the wheel end required torque is large due to the consideration of dynamic property.

In combination with the above-mentioned vehicle speed influence, for entering the parallel mode, especially for the switching working condition of series connection and parallel connection in normal running, the vehicle speed for maintaining the lowest rotation speed of the engine with the lowest gear (the maximum speed ratio) is generally impossible to be 0 in parallel connection precursor, so that the vehicle speed is the premise of entering the parallel connection, the parallel connection can be allowed when the vehicle speed is larger than a certain vehicle speed, and meanwhile, the parallel connection can be performed when the vehicle speed is higher than a certain value under the lower vehicle speed, mainly in series connection, based on the consideration of economy. In addition, when NVH is considered, the rotating speed of the engine for series power generation is not too high, so that the series and parallel switching speed can be obtained according to the rotating speed of the engine, furthermore, the series and parallel switching speed can also be obtained based on a gear shifting line of a gearbox, and of course, the embodiment based on the intention of a driver can be combined, and further, in addition, under the condition of sudden acceleration (full throttle), the driver needs large torque, so that a low gear and large speed ratio can be selected, and meanwhile, under the condition of sudden acceleration, the series and parallel switching speed can be reduced, so that the vehicle can enter a parallel mode as soon as possible.

After the vehicle speed condition meets the switching requirement, a minimum torque value in a parallel mode can be calculated according to the current vehicle speed, the battery capacity, the current electric quantity, the speed ratio of a preselected gear and the like, and therefore, the calculation result shows that once the requirement enters parallel, the required torque of the wheel end is larger than the minimum torque value.

In connection with the architectural embodiment described above involving a 4-speed transmission, the entire vehicle cannot be directly shifted from series (a-clutch) to parallel 4-speed, only to parallel 1/2/3-speed, because of the parallel 4-speed use of clutches C and D.

Thus, during series drive, the TCU calculates an ideal pre-selected gear in real time based on vehicle speed, throttle, engine speed, etc., where the ideal gear is the currently calculated relatively optimal gear.

Before the VCU sends a parallel mode switching request to the TCU, the GCU is required to be regulated according to the speed ratio of a preselected gear sent by the TCU, the current speed and the rotation speed of the front shaft output shaft, specifically, in the speed regulating process, the VCU sends a prefill oil command to the TCU, and the TCU searches a corresponding clutch according to the current preselected gear and fills oil to enable the corresponding clutch to be at a point Kisspoint (half-combining point). It should be added here that the pre-fueling in advance prevents the TCU from shifting to a preselected gear due to a change in vehicle speed or other reasons.

Thereafter, the TCU waits for the VCU to initiate a parallel mode, and the TCU performs a closing clutch action. If in the process the preselected gear is changed due to network delays, the VCU resumes the above-described speed regulation with the changed preselected gear. Then, after the clutch is closed, the TCU updates the current actual gear to parallel 1/2/3 gear, and the VCU changes the current mode to parallel mode.

Finally, it may be further described that, in combination with the embodiment based on the user intention, if the GCU is in the working condition that the rotation speed mode is switched to the torque mode, the VCU allocates the torques of the ECU, the GCU and the MCU according to the current vehicle speed, the electric quantity, the accelerator and other vehicle states. For example, the current vehicle speed and the electric quantity are higher, the user is driven by a large accelerator, after the actual mode of the whole vehicle enters in parallel from serial connection, the original driving force of the whole vehicle is all from an MCU, and in consideration of power and safety, part of the driving force of the MCU needs to be transferred to a front axle to be distributed by the ECU and the GCU, the vehicle is in parallel connection with four-wheel drive and GCU power assisted, if the current electric quantity is low, the GCU can possibly separate part of negative torque for generating power, the MCU can only recover energy, the driving force of the whole vehicle is borne by the ECU, and the vehicle is in a parallel connection precursor power generation state.

In summary, the main design concept of the invention is that, aiming at the architecture of the hybrid electric vehicle with the P2.5+p4 of the four-gear transmission, the control of the engine starting scene and the hybrid mode working condition is designed in a targeted manner, and mainly comprises the steps of presetting a forced power generation area and a priority power generation area of a battery, starting the engine to keep power if the SOC is in the forced power generation area, starting the engine to generate power if the SOC is in the priority power generation area and the vehicle runs at a preset speed, and correspondingly starting the engine to enter a series mode or a parallel mode respectively if the battery or the motor has a large long-time work load when the vehicle runs normally in the pure electric mode. Furthermore, the invention provides detailed implementation references for the process and the details related to the mode switching, and provides an ideal solution for the mode control of the P2.5+P4 architecture hybrid vehicle.

In embodiments of the present invention, when reference is made to a phrase that expresses an orientation, it is based on the relative concepts of the embodiments, with the proviso that "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relation of association objects, and indicates that there may be three kinds of relations, for example, a and/or B, and may indicate that a alone exists, a and B together, and B alone exists. Wherein A, B may be singular or plural. The character "/" generally indicates that the context-dependent object is an "or" relationship. "at least one of the following" and the like means any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c may represent a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c may be single or plural.

The construction, features and effects of the present invention are described in detail with reference to the embodiments shown in the drawings, but the above-mentioned embodiments and the technical features related to the preferred embodiments are only preferred embodiments of the present invention, and it should be understood that those skilled in the art may reasonably combine and arrange the above-mentioned embodiments into various equivalent schemes without departing from or changing the design concept and technical effects of the present invention, so that the present invention is not limited by the scope of the embodiments shown in the drawings, and all changes made according to the concepts of the present invention or modifications to equivalent embodiments are within the scope of the present invention without departing from the spirit covered by the specification and drawings.

Claims

1. The mode control method of the hybrid electric vehicle comprises a whole vehicle controller, a rear motor controller, a gearbox controller, a front motor controller and an engine controller, and the hybrid electric vehicle is provided with a four-gear gearbox with four clutches, and is characterized by comprising the following steps of:

Executing different mode judging mechanisms according to the operation intention of a driver, namely starting an engine to enter a parallel mode if a full accelerator acceleration condition is detected when the vehicle runs normally in pure electricity, starting the engine to enter a series mode if the vehicle is detected to park in P gear and an accelerator pedal is stepped down, or receiving a user trigger to enter an in-situ power-up function;

The vehicle controller judges the target mode requirement according to the obtained serial mode capability, parallel mode capability and wheel end required torque:

If the current parallel mode capability is greater than the series mode capability and the wheel end required torque is greater than the series mode capability, the target mode requirement is to enter a parallel mode;

if the current series mode capability is greater than the parallel mode capability and the wheel end required torque is greater than the parallel mode capability, the target mode requirement is to enter a series mode;

if the series capacity is similar to the parallel capacity, deciding to enter a series mode or a parallel mode based on the current series capacity and the parallel capacity only when the torque required by the wheel end is larger;

The control method further comprises the following steps:

2. The method of claim 1, wherein the starting the engine into the series mode comprises:

3. The method of controlling a mode of a hybrid vehicle of claim 2, further comprising distributing torque to the engine, the front motor, and the rear motor based on a current vehicle speed, an SOC, an accelerator opening, and a vehicle state if the front motor controller is switched from the rotational speed mode to the torque mode.

4. The method for mode control of a hybrid vehicle according to claim 1, the control method is characterized by further comprising a target mode demand decision mechanism:

series mode capability = { [ battery available power + (engine available power, front motor available power) min ], rear motor available power } _min;

Parallel mode capability = engine available power + [ battery available power, (front motor available power + rear motor available power) ] _min.

5. The method according to claim 1, wherein the switching vehicle speed threshold is obtained according to an engine speed or a shift line based on a transmission, and the switching vehicle speed threshold is lowered if a rapid acceleration condition is currently in.

6. The method for controlling a mode of a hybrid vehicle according to claim 1, characterized in that the method for controlling a mode further comprises:

7. The method according to claim 6, wherein if the preselected gear is changed, the whole vehicle controller resumes the speed regulation according to the changed preselected gear.

8. The method according to claim 6 or 7, characterized in that the step of adjusting the speed of the front motor includes: