CN112109697B

CN112109697B - Control method and device for preventing motor overheating of hybrid electric vehicle and controller

Info

Publication number: CN112109697B
Application number: CN202011004558.9A
Authority: CN
Inventors: 吴肇苏; 张丽; 章国光; 许永红; 李松
Original assignee: Dongfeng Motor Corp
Current assignee: Dongfeng Motor Corp
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2022-02-01
Anticipated expiration: 2040-09-22
Also published as: CN112109697A

Abstract

The invention discloses a control method, a control device and a control device for preventing a motor of a hybrid electric vehicle from overheating, belonging to the field of motor control, wherein the method comprises the following steps: acquiring the speed or the rotating speed, the motor temperature, the residual battery capacity and the pedal opening from the CAN bus, and acquiring the required torque of the vehicle according to the pedal opening, wherein the vehicle is a two-drive hybrid vehicle or a four-drive hybrid vehicle; and determining the working mode of the vehicle according to the temperature of the motor, the required torque and the residual battery capacity, and controlling the connection or disconnection of the clutch according to the requirements of different working modes. The invention can improve the dynamic property of the vehicle and improve the capabilities of accelerating climbing, escaping from difficulties and the like; safety, the risk of damaging the motor is reduced.

Description

Control method and device for preventing motor overheating of hybrid electric vehicle and controller

Technical Field

The invention belongs to the field of motor control, and particularly relates to a control method and device for preventing a motor of a hybrid electric vehicle from being overheated and a vehicle control unit.

Background

Compared with the traditional automobile which only uses fuel to drive an engine, the hybrid electric vehicle has different power system working modes due to the addition of a motor and a power battery, so that the requirement on the control technology is higher.

The motor of the hybrid electric vehicle can work in two different working states, namely an electric state and a power generation state. When the motor of the hybrid electric vehicle works in an electric state, the electric energy in the storage battery is converted into mechanical energy to drive the vehicle to run, and when the motor of the hybrid electric vehicle works in a power generation state, the mechanical energy is converted into electric energy to be stored in the storage battery. In any state of the motor, the temperature of the motor changes due to the change of the torque of the motor, especially in the case of large required torque (such as accelerating climbing and getting rid of trouble), the motor may not provide enough power to meet the requirement of a driver, and the motor may be over-heated in a high-load state. The performance of the motor may be affected if the motor temperature overheats.

Therefore, how to control the hybrid electric vehicle to prevent the motor from overheating is a technical problem which needs to be solved urgently at present.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides a control method and device for preventing overheating of a motor of a hybrid electric vehicle and a vehicle control unit, which can prevent the motor from being overheated due to high-load work of a driving motor on the premise of not influencing the dynamic property of the vehicle.

To achieve the above object, according to one aspect of the present invention, there is provided a control method of a hybrid vehicle for preventing overheating of a motor, including:

(1) acquiring the speed or the rotating speed, the motor temperature, the battery residual capacity and the pedal opening from a CAN bus, and acquiring the required torque of the vehicle according to the pedal opening, wherein the vehicle is a two-drive hybrid vehicle or a four-drive hybrid vehicle;

(2) and determining the working mode of the vehicle according to the motor temperature, the required torque and the residual battery capacity, and controlling the connection or disconnection of the clutch according to the requirements of different working modes.

In some alternative embodiments, for a two-drive hybrid vehicle, step (2) comprises:

(2.1) setting a first preset vehicle speed V1 or a first preset rotating speed N1, and setting an idle speed V2 or an idle speed N2;

(2.2) when the vehicle speed is less than V2 or the rotating speed is less than N2, the related working modes comprise a pure electric mode, an idle charging mode, a series mode and an energy recovery mode;

(2.3) when the vehicle speed is greater than V1 or the rotating speed is greater than N1, determining the working mode of the vehicle according to the required torque and the residual capacity of the battery, and controlling the connection or disconnection of the clutch according to the requirements of different working modes;

(2.4) when the vehicle speed is more than V2 and less than V1 or the rotating speed is more than N2 and less than N1, carrying out secondary judgment according to the motor temperature, the required torque and the residual battery capacity, determining whether to engage the clutch, and defining the current working mode, wherein the working modes involved at the moment comprise a pure engine mode, a parallel mode, a series-parallel mode, a double-motor mode and an energy recovery mode.

In some alternative embodiments, for a two-drive hybrid vehicle, step (2.4) comprises:

(2.4.1) setting a temperature T0 according to the performance of the motor, judging whether the temperature of the motor exceeds a set temperature T0 when V2 is less than the vehicle speed and less than V1 or N2 is less than the rotating speed and less than N1, and executing the step (2.4.2) if the temperature of the motor is more than T0;

(2.4.2) setting a first required torque T1 and a second required torque T2, and setting a first remaining capacity S1, a second remaining capacity S2, and a third remaining capacity S3, wherein T1 < T2, S2 < S3 < S1;

(2.4.3) engaging the clutch when the required torque is less than T1, and when the battery remaining capacity is greater than S1, the vehicle enters an engine-only mode, the fuel tank supplies fuel to the engine, the vehicle is driven by the engine alone, and activation of energy recovery is not allowed; when the residual battery capacity is less than S1, the vehicle enters a pure engine mode, the oil tank supplies oil to the engine, the engine drives the vehicle independently, and energy recovery is allowed to be activated;

(2.4.4) when the required torque is greater than T1 and less than T2, engaging the clutch and not allowing the energy recovery to be activated, and when the residual capacity of the battery is greater than S2, engaging the clutch and enabling the vehicle to enter a parallel mode, wherein the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, and the power battery supplies power to the driving battery; when the residual electric quantity of the battery is less than S2, the vehicle enters a series-parallel mode, the engine and the driving motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together;

(2.4.5) when the required torque is greater than T1 and the required torque is greater than T2, engaging the clutch and not allowing the energy recovery to be activated, when the residual capacity of the battery is greater than S3, enabling the vehicle to enter a dual-motor mode, supplying oil to the engine by an oil tank, supplying power to the driving motor and the engine by a power battery, and driving the vehicle by the engine, the driving motor and the generator together; when the residual electric quantity of the battery is less than S3, the vehicle enters a series-parallel mode, the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together.

In some alternative embodiments, for a two-drive hybrid vehicle, if the motor temperature is less than T0 or the vehicle speed is less than V2 or the rotating speed is less than N2, the clutch is disconnected, and a fourth remaining battery capacity S4 is set according to the power supply capacity of the battery, wherein S4 is less than S2 and less than S1;

when the residual electric quantity of the battery is less than S4, the vehicle enters an idle charging mode, the oil tank supplies oil to the engine, the engine works, and the generator charges the power battery to allow the activation of energy recovery;

when the residual battery capacity is greater than S4 and the residual battery capacity is greater than S1, the vehicle enters a pure electric mode, the power battery supplies power to the driving motor, the driving motor drives the vehicle, and the activation of energy recovery is not allowed;

when the residual battery capacity is greater than S4 and S1 is greater than the residual battery capacity is greater than S2, the vehicle enters a pure electric mode, the power battery supplies power to the driving motor, and the driving motor drives the vehicle to allow the energy recovery to be activated;

when the residual electric quantity of the battery is less than S2, the vehicle enters a series mode, the driving motor drives the vehicle, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the driving motor.

In some alternative embodiments, for a four-drive hybrid vehicle, step (2) comprises:

(2.2) when the vehicle speed is less than V2 or the rotating speed is less than N2, the related working modes comprise a pure electric forerunner mode, an idle charging mode, a series forerunner mode and energy recovery;

and (2.4) when the vehicle speed is more than V2 and less than V1 or the rotating speed is more than N2 and less than N1, performing secondary judgment according to the motor temperature, the required torque and the battery residual capacity, determining whether to engage the clutch, and defining the current working mode, wherein the working modes involved at the moment comprise a pure electric rear-drive mode, a series rear-drive mode, a parallel four-drive mode, a series four-drive mode, a double-motor four-drive mode and an energy recovery mode.

In some alternative embodiments, for a four-drive hybrid vehicle, step (2.4) comprises:

(2.4.2) setting the first required torque T1 and the second required torque T2, and setting the first remaining capacity S1, the second remaining capacity S2, and the third remaining capacity S3, wherein T1 < T2, S2 < S3 < S1

(2.4.3) when the required torque is less than T1, disconnecting the clutch, when the residual electric quantity of the battery is greater than S1, enabling the vehicle to enter a pure electric rear-drive mode, supplying power to a rear-drive motor by a power battery, and driving the vehicle by the rear-drive motor independently without allowing to activate energy recovery; when the battery residual capacity is more than S2 and less than S1, the power battery supplies power to the rear drive motor, the rear drive motor drives the vehicle independently, and the energy recovery is allowed to be activated; when the residual electric quantity of the battery is less than S2, the vehicle enters a series rear-drive mode, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the rear-drive motor;

(2.4.4) when T2 is larger than the required torque and is larger than T1, and when the residual electric quantity of the battery is larger than S2, engaging the clutch, enabling the vehicle to enter a parallel four-wheel drive mode, enabling the engine and the rear-drive motor to drive the vehicle together, supplying oil to the engine by an oil tank, and supplying power to the rear-drive motor by a power battery; when the residual electric quantity of the battery is less than S2, the clutch is engaged, the vehicle enters a series-parallel four-wheel drive mode, the engine and the rear-drive motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, the generator and the power battery supply power to the rear-drive motor together, and the activation of energy recovery is not allowed;

(2.4.5) when the required torque is larger than T1 and the required torque is larger than T2, engaging the clutch, not allowing to activate energy recovery, when the remaining battery capacity is larger than S3, enabling the vehicle to enter a dual-motor four-wheel drive mode, supplying oil to the engine by an oil tank, supplying power to the front-drive motor and the rear-drive motor by a power battery, and driving the vehicle by the engine, the front-drive motor and the rear-drive motor together; when the residual electric quantity of the battery is less than S3, the vehicle enters a series-parallel four-wheel drive mode, the engine and the rear-drive motor drive the vehicle together, the oil tank supplies oil to the engine, and the engine and the power battery supply power to the rear-drive motor together.

In some alternative embodiments, for a four-wheel drive hybrid vehicle, if the vehicle speed is less than V2 or the motor temperature is less than T0 or the rotating speed is less than N2, the clutch is disconnected, and the fourth remaining battery capacity S4 is set according to the power supply capacity of the battery, wherein S4 is less than S2 is less than S1:

when the residual battery capacity is greater than S4 and the residual battery capacity is greater than S1, the vehicle enters a pure electric forerunner mode, the power battery supplies power to the forerunner motor, the driving motor drives the vehicle, and the activation of energy recovery is not allowed;

when the battery residual capacity is greater than S4 and S1 is greater than the battery residual capacity is greater than S2, the vehicle enters a pure electric forerunner mode, the power battery supplies power to the forerunner motor, the driving motor drives the vehicle, and the activation energy recovery is allowed;

when the residual electric quantity of the battery is less than S2, the vehicle enters a series-connection forerunner mode, a forerunner motor drives the vehicle, an oil tank supplies oil to an engine, the engine works to drive a generator to generate electricity, and the generator and a power battery jointly supply power to a driving motor.

According to another aspect of the present invention, there is provided a control apparatus for a hybrid vehicle for preventing overheating of a motor, including:

the system comprises a signal acquisition unit, a controller and a control unit, wherein the signal acquisition unit is used for acquiring the speed or the rotating speed, the motor temperature, the residual battery capacity and the pedal opening from a CAN bus and acquiring the required torque of the vehicle according to the pedal opening, and the vehicle is a two-drive hybrid vehicle or a four-drive hybrid vehicle;

and the control unit is used for determining the working mode of the vehicle according to the motor temperature, the required torque and the residual battery capacity and controlling the connection or disconnection of the clutch according to the requirements of different working modes.

According to another aspect of the present invention, a vehicle control unit including the control apparatus for preventing overheating of a motor of the hybrid vehicle is provided.

According to another aspect of the invention, a computer-readable storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any of the above.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

1. the combination condition, the constraint energy recovery and the switching working mode of the clutch are more reasonably given by combining the vehicle speed/the rotating speed with the temperature change of the driving motor, the torque required by a driver and the electric quantity of the battery.

2. On the premise of not influencing the dynamic property of the vehicle, the over-temperature of the motor caused by the high-load work of the driving motor is prevented.

3. The control method can improve the dynamic property of the vehicle and improve the capabilities of accelerating climbing, escaping from difficulties and the like; safety, the risk of damaging the motor is reduced.

Drawings

FIG. 1 is a flowchart illustrating a method for controlling a hybrid vehicle to prevent overheating of a motor according to an embodiment of the present invention;

FIG. 2 is a two-drive configuration diagram provided by an embodiment of the present invention;

FIG. 3 is a schematic flow chart of a two-drive control method according to an embodiment of the present invention;

FIG. 4 is a diagram of a four-wheel drive configuration provided by an embodiment of the present invention;

fig. 5 is a schematic flowchart of a four-wheel drive control method according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the present examples, "first", "second", etc. are used for distinguishing different objects, and are not necessarily used for describing a particular order or sequence.

The invention provides a control method for preventing overheating of a motor, aiming at a hybrid electric vehicle. The combination condition, the constraint energy recovery and the switching working mode of the clutch are more reasonably given by combining the temperature change of the driving motor, the torque required by a driver and the electric quantity of the battery, so that the driving motor is prevented from being over-heated due to high-load work on the premise of not influencing the dynamic property of the vehicle. Under the premise of not changing a motor system and a control circuit, the problem that the motor works under high load and is overheated due to the fact that a clutch cannot be combined is solved, and the vehicle can smoothly realize working conditions such as accelerated climbing and escaping.

Fig. 1 is a schematic flow chart of a method for controlling a hybrid electric vehicle to prevent overheating of a motor according to an embodiment of the present invention, including the following steps:

s1: acquiring the speed or the rotating speed, the motor temperature, the residual battery capacity and the pedal opening from the CAN bus, and acquiring the required torque of the vehicle according to the pedal opening, wherein the vehicle is a two-drive hybrid vehicle or a four-drive hybrid vehicle;

s2: and determining the working mode of the vehicle according to the temperature of the motor, the required torque and the residual battery capacity, and controlling the connection or disconnection of the clutch according to the requirements of different working modes.

Example one

In the embodiment of the invention, for the two-drive hybrid vehicle, the control flow is as follows:

(1) as shown in fig. 2, the power system includes an oil tank 3, a power battery 6, an engine 2, a driving motor 5, a clutch 9, a transmission 8, a generator 10, a Vehicle controller 1, a motor controller 4, and a differential 7, wherein the oil tank 3 is connected to the engine 2, the engine 2 is connected to the generator 10 via a fixed speed ratio, the engine 2 is connected to the clutch 9, the clutch 9 is connected to the transmission 8, the driving motor 5 is connected to the transmission 8, the Vehicle controller (VECU) is connected to the engine 2 and the clutch 9, the battery 6 is connected to the motor controller 4, and the motor controller 4 is connected to the driving motor 5 and the generator 10.

(2) The vehicle control unit obtains a vehicle speed/rotating speed, a motor temperature, a battery electric quantity and a pedal opening degree signal from the CAN bus, and calculates a required torque of the vehicle according to the pedal opening degree.

(3) As shown in fig. 3, the engine driving is determined based on the vehicle speed or the rotational speed. In the embodiment of the invention, the vehicle speed is taken as an example of the judgment condition, the rotating speed is similar to the vehicle speed, the vehicle speed V1 is set according to the working characteristics of the engine, the driving efficiency of the engine is high when the vehicle speed is more than V1, the idling vehicle speed is set as V2, and the engine can be normally driven when the vehicle speed is more than V2.

(4) When the vehicle speed is more than V2 and less than V1, the related working modes comprise a pure engine mode, a parallel mode, a series-parallel mode, a double-motor mode and energy recovery.

(5) When the vehicle speed is less than V2, the working modes include pure electric mode, idle charging mode, series mode and energy recovery.

(6) When the vehicle speed is greater than V1, the vehicle control unit determines the working mode of the vehicle (such as a pure electric mode, a pure engine mode, a series mode and the like) according to the required torque and the battery power signal, and controls the connection and disconnection of the clutch according to the requirements of different working modes, and when the vehicle speed is greater than V1, the related control strategy is mature and the description is not provided.

(7) In the pure engine mode, the vehicle controller controls the combination of the clutch and the driving of the engine; in the parallel mode, the vehicle controller controls the clutch combination and the engine driving, and the motor controller controls the driving motor driving; in the hybrid mode, the vehicle control unit controls the combination of the clutch and the driving of the engine, and the motor controller controls the power generation of the engine and drives the driving of the motor; in the pure electric mode, the vehicle control unit controls the clutch to be disconnected, and the motor controller controls the driving motor to drive; in the series mode, the vehicle control unit controls the clutch to be disconnected and the engine to work, and the motor controller controls the engine to generate power and drives the motor to drive; in the dual-motor mode, the vehicle control unit controls the clutch combination and the engine driving, and the motor controller controls the engine and drives the motor driving; in the idle charging mode, the vehicle control unit controls the clutch to be disconnected and the engine to work, and the motor controller controls the engine to generate power; the energy recovery motor controller of the engine controls the motor to reversely rotate to recover energy to the battery.

(8) Firstly, the VECU judges the vehicle speed, and when the vehicle speed is more than V2 and less than V1, secondary judgment is carried out according to the motor temperature, the required torque signal and the battery electric quantity signal, whether the clutch is combined is determined, and the current working mode is defined.

(9) According to the performance setting temperature T0 of the motor, when the vehicle speed is more than V2 and less than V1, the VECU judges whether the temperature of the motor exceeds the setting temperature T0 or not, and when the temperature of the motor is higher than T0, an over-temperature fault occurs if the high-load work is continued; if the motor temperature is greater than T0, the VECU needs to further judge the required torque and the residual capacity. Setting the required torques T1, T2 according to the power demand, when the required torque is less than T1, the engine can provide enough torque; when the required torque is greater than T1 and less than T2, the engine and the driving motor are required to provide torque together, and energy recovery is not allowed to be activated; when the required torque is greater than T2, the engine, the drive motor, and the generator are required to together provide torque, and energy recovery is not allowed to be activated. Setting residual electric quantity S1, S2 and S3 according to the power supply/recovery capacity of the battery, wherein the power battery is allowed to be charged only when the electric quantity is less than S1; the power battery power residual capacity can provide enough power for the driving motor to drive only when the power battery power residual capacity is greater than S2; the power battery power residual capacity is larger than S3, and enough power can be provided for the driving motor and the generator to drive. Wherein T1 < T2, S2 < S3 < S1:

when the VECU detects that the required torque is larger than T1 and the required torque is larger than T2, the VECU is combined with the clutch, energy recovery is not allowed to be activated, if the residual electric quantity of the battery is larger than S3, the vehicle enters a dual-motor mode, the oil tank supplies oil to the engine, the power battery supplies power to the driving motor and the engine, the driving motor and the generator drive the vehicle together; if the residual electric quantity of the battery is less than S3, the vehicle enters a series-parallel mode, the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together.

When the VECU detects that the required torque is less than T1, the clutch is combined, if the residual electric quantity of the battery is greater than S1, the vehicle enters a pure engine mode, the oil tank supplies oil to the engine, the engine drives the vehicle independently, and the energy recovery is not allowed to be activated; if the remaining battery capacity is less than S1, the vehicle enters the engine only mode, the fuel tank supplies fuel to the engine, and the vehicle is driven by the engine alone, allowing energy recovery to be activated.

When the T2 is larger than the required torque and is larger than T1, the clutch is combined, the energy recovery is not allowed to be activated, if the residual electric quantity of the battery is larger than S2, the clutch is engaged, the vehicle enters a parallel connection mode, the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, and the power battery supplies power to the driving battery; if the residual electric quantity of the battery is less than S2, the vehicle enters a series-parallel mode, the engine and the driving motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together.

(10) And the VECU judges the vehicle speed, and when the vehicle speed is less than V2 or the motor temperature is less than T0, the clutch is disconnected, secondary judgment is carried out according to the required torque signal and the battery power signal, and the current working mode is defined.

(11) When the vehicle speed is less than V2 or the motor temperature is less than T0, the residual battery capacity S4 is set according to the power supply capacity of the battery, when the electric quantity is less than S4, the vehicle cannot be started by means of the driving motor, the engine needs to work, the generator is driven to generate electricity to provide electric energy, and S4 is less than S2 and less than S1:

when the VECU detects that the residual electric quantity of the battery is less than S4, the vehicle enters an idling charging mode, the oil tank supplies oil to the engine, the engine works, and the generator charges the power battery to allow the energy recovery to be activated.

When the VECU detects that the residual battery capacity is greater than S4 and the residual battery capacity is greater than S1, the vehicle enters a pure electric mode, the power battery supplies power to the driving motor, the driving motor drives the vehicle, and the energy recovery is not allowed to be activated.

When the VECU detects that the residual battery capacity is greater than S4 and S1 is greater than the residual battery capacity is greater than S2, the vehicle enters a pure electric mode, the power battery supplies power to the driving motor, and the driving motor drives the vehicle to allow energy recovery to be activated.

When the VECU detects that the residual electric quantity of the battery is less than S2, the vehicle enters a series mode, the driving motor drives the vehicle, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the driving motor.

(12) All the above settings can be obtained by calibration.

Example two

In the embodiment of the invention, for a four-wheel drive hybrid vehicle, the control flow is as follows:

in the embodiment of the invention, for a four-wheel drive hybrid vehicle, only the case that the rear axle has no clutch is listed, and the control flow is as follows:

(1) as shown in fig. 4, the power system comprises an oil tank 3, a power battery 6, an engine 2, a front drive motor 5, a rear drive motor 10, a clutch 13, a first transmission 12, a second transmission 9, a generator 14, a vehicle control unit 1, a front drive motor controller 4, a rear drive motor controller 7, a first differential 11 and a second differential 8, the oil tank 3 is connected with the engine 2, the engine 2 is connected with the generator 14 through a fixed speed ratio, the engine 2 is connected with the clutch 13, the clutch 13 is connected with the first transmission 12, the front-drive motor 5 is connected with the first transmission 12, the vehicle control unit VECU 1 is connected with the engine 2 and the clutch 13, the battery 6 is connected with the front-drive motor controller 4 and the rear-drive motor controller 7, the front-drive motor controller 4 is connected with the front-drive motor 5 and the generator 14, and the rear-drive motor controller 7 is connected with the rear-drive motor 10.

(3) According to the vehicle speed or the rotation speed as the judgment basis of the engine driving, as shown in fig. 5, the vehicle speed is taken as an example of the judgment condition, the rotation speed is similar, according to the working characteristic of the engine, in order to improve the economy of the vehicle, the vehicle speed V1 is set, when the vehicle speed is more than V1, the efficiency of the engine driving is high, the vehicle speed in the idling condition is set as V2, and when the vehicle speed is more than V2, the engine can be normally driven.

(4) When the vehicle speed is more than V2 and less than V1, the related working modes comprise a pure electric rear-drive mode, a series rear-drive mode, a parallel four-drive mode, a series four-drive mode, a double-motor four-drive mode and energy recovery.

(5) When the vehicle speed is less than V2, the related working modes comprise an electric-only forward driving mode, an idle charging mode, a series forward driving mode and energy recovery.

(6) When the vehicle speed is greater than V1, the vehicle control unit determines the working mode of the vehicle (such as a pure electric forward driving mode, a pure engine mode, a series forward driving mode and the like) according to the required torque and the battery power signal, and controls the connection and disconnection of the clutch according to the requirements of different working modes, and because the vehicle speed is greater than V1, the related control strategy is mature and is not described.

(7) In the pure electric forward driving mode, the vehicle control unit controls the clutch to be disconnected, and the forward driving motor controller controls the forward driving motor to drive; in the pure electric rear-drive mode, the vehicle control unit controls the clutch to be disconnected, and the rear-drive motor controller controls the rear-drive motor to drive; in the parallel four-wheel drive mode, the vehicle control unit controls the clutch combination and the engine drive, and the rear-drive motor controller controls the rear-drive motor drive; in the hybrid mode, the vehicle control unit controls the combination of the clutch and the driving of the engine, the front drive motor controller controls the power generation of the engine, and the rear drive motor controller drives the rear drive motor to drive; in the series-connection forerunner mode, the vehicle control unit controls the clutch to be disconnected and the engine to work, and the forerunner motor controller controls the engine to generate power and the forerunner motor to drive; in the dual-motor four-wheel drive mode, the vehicle controller controls the clutch combination and the engine drive, the front-drive motor controller controls the engine and the front-drive motor drive, and the rear-drive motor controller controls the rear-drive motor drive; in the idle charging mode, the vehicle control unit controls the clutch to be disconnected and the engine to work, and the front-drive motor controller controls the engine to generate power; the energy recovery front driving/rear driving motor controller controls the front driving/rear driving motor to reversely rotate to recover energy to the battery.

(8) According to the performance setting temperature T0 of the motor, when the vehicle speed is more than V2 and less than V1, the VECU judges whether the temperature of the motor exceeds the setting temperature T0 or not, and when the temperature of the motor is higher than T0, an over-temperature fault occurs if the high-load work is continued; if the motor temperature is greater than T0, the VECU needs to further judge the required torque and the residual capacity. Setting the required torques T1 and T2 according to the power requirement, wherein when the required torque is less than T1, the rear-drive motor can provide enough torque; when the required torque is greater than T1 and less than T2, the engine and the rear drive motor are required to provide torque together, and energy recovery is not allowed to be activated; when the required torque is greater than T2, the engine, the rear drive motor and the generator are required to provide torque together, and energy recovery is not allowed to be activated. Setting residual electric quantity S1, S2 and S3 according to the power supply/recovery capacity of the battery, wherein the power battery is allowed to be charged only when the electric quantity is less than S1; the power battery power residual capacity can provide enough power for the rear drive motor to drive only when the power battery power residual capacity is greater than S2; the power battery power residual capacity is larger than S3, and enough power can be provided for the front driving motor and the rear driving motor to drive. Wherein T1 < T2, S2 < S3 < S1:

when the VECU detects that the required torque is larger than T1 and the required torque is larger than T2, the VECU combines a clutch and does not allow to activate energy recovery, if the remaining electric quantity of the battery is larger than S3, the vehicle enters a dual-motor four-drive mode, an oil tank supplies oil to the engine, a power battery supplies power to the front-drive motor and the rear-drive motor, and the engine, the front-drive motor and the rear-drive motor drive the vehicle together; if the residual electric quantity of the battery is less than S3, the vehicle enters a series-parallel four-wheel drive mode, the engine and the rear-drive motor drive the vehicle together, the oil tank supplies oil to the engine, and the engine and the power battery supply power to the rear-drive motor together.

When the VECU detects that the required torque is less than T1, the clutch is disconnected, if the residual electric quantity of the battery is greater than S1, the vehicle enters a pure electric rear-drive mode, the power battery supplies power to the rear-drive motor, the rear-drive motor drives the vehicle independently, and the activation of energy recovery is not allowed; if the battery residual capacity is less than S1 and S2, the power battery supplies power to the rear-drive motor, the rear-drive motor drives the vehicle independently, and the energy recovery is allowed to be activated; if the residual electric quantity of the battery is less than S2, the vehicle enters a series rear-drive mode, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the rear-drive motor.

When the T2 is larger than the required torque and is larger than T1, if the residual electric quantity of the battery is larger than S2, the clutch is engaged, the vehicle enters a parallel four-wheel drive mode, the engine and the rear-drive motor drive the vehicle together, the oil tank supplies oil to the engine, and the power battery supplies power to the rear-drive motor; if the residual electric quantity of the battery is less than S2, the vehicle enters a series-parallel four-wheel drive mode, the engine and the rear-drive motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the rear-drive motor together.

(9) And the VECU judges the vehicle speed, and when the vehicle speed is less than V2 or the motor temperature is less than T0, the clutch is disconnected, secondary judgment is carried out according to the required torque signal and the battery power signal, and the current working mode is defined.

(10) When the vehicle speed is less than V2 or the motor temperature is less than T0, the residual battery capacity S4 is set according to the power supply capacity of the battery, when the electric quantity is less than S4, the vehicle cannot be started by means of the driving motor, the engine needs to work, the generator is driven to generate electricity to provide electric energy, and S4 is less than S2 and less than S1:

When the VECU detects that the residual battery capacity is larger than S4 and the residual battery capacity is larger than S1, the vehicle enters a pure electric forward driving mode, the power battery supplies power to the forward driving motor, the driving motor drives the vehicle, and the energy recovery is not allowed to be activated.

When the VECU detects that the residual battery capacity is greater than S4 and S1 is greater than the residual battery capacity is greater than S2, the vehicle enters a pure electric forward driving mode, the power battery supplies power to the forward driving motor, the driving motor drives the vehicle, and energy recovery is allowed to be activated.

When the VECU detects that the residual electric quantity of the battery is less than S2, the vehicle enters a series-connection forerunner mode, the forerunner motor drives the vehicle, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the driving motor.

(11) All the above settings can be obtained by calibration.

EXAMPLE III

In another embodiment of the present invention, there is also provided a control apparatus for a hybrid vehicle for preventing overheating of a motor, including:

the signal acquisition unit is used for acquiring the speed or the rotating speed, the motor temperature, the residual battery capacity and the pedal opening from the CAN bus and acquiring the required torque of the vehicle according to the pedal opening, wherein the vehicle is a two-drive hybrid vehicle or a four-drive hybrid vehicle;

and the control unit is used for determining the working mode of the vehicle according to the temperature of the motor, the required torque and the residual battery capacity and controlling the connection or disconnection of the clutch according to the requirements of different working modes.

The embodiments of the present invention will not be repeated herein, and reference may be made to the description of the method embodiments above for the specific implementation of each unit.

Example four

The present application also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a Random Access Memory (RAM), a Static Random Access Memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application mall, etc., on which a computer program is stored, which when executed by a processor implements the control method of the hybrid electric vehicle for preventing the motor from overheating in the method embodiments.

It should be noted that, according to the implementation requirement, each step/component described in the present application can be divided into more steps/components, and two or more steps/components or partial operations of the steps/components can be combined into new steps/components to achieve the purpose of the present invention.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A control method for preventing overheating of a motor of a hybrid electric vehicle is characterized by comprising the following steps:

(2) determining the working mode of the vehicle according to the motor temperature, the required torque and the residual battery capacity, and controlling the connection or disconnection of a clutch according to the requirements of different working modes;

for a two-drive hybrid vehicle, step (2) comprises:

(2.4) when the vehicle speed is more than V2 and less than V1 or the rotating speed is more than N2 and less than N1, carrying out secondary judgment according to the motor temperature, the required torque and the residual battery capacity, determining whether to engage a clutch, and defining the current working mode, wherein the working mode comprises a pure engine mode, a parallel mode, a series-parallel mode, a double-motor mode and an energy recovery mode;

for a two-drive hybrid vehicle, step (2.4) comprises:

(2.4.4) when the required torque is greater than T1 and less than T2, engaging the clutch and not allowing to activate energy recovery, and when the residual capacity of the battery is greater than S2, engaging the clutch and enabling the vehicle to enter a parallel mode, wherein the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, and the power battery supplies power to the driving motor; when the residual electric quantity of the battery is less than S2, the vehicle enters a series-parallel mode, the engine and the driving motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together;

(2.4.5) when the required torque is greater than T1 and the required torque is greater than T2, engaging the clutch and not allowing the energy recovery to be activated, when the residual capacity of the battery is greater than S3, enabling the vehicle to enter a dual-motor mode, supplying oil to the engine by an oil tank, supplying power to the driving motor and the engine by a power battery, and driving the vehicle by the engine, the driving motor and the generator together; when the residual electric quantity of the battery is less than S3, the vehicle enters a series-parallel mode, the engine and the motor drive the vehicle together, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery supply power to the driving motor together;

for a four-wheel drive hybrid vehicle, the step (2) comprises the following steps:

(2.2) when the vehicle speed is less than V2 or the rotating speed is less than N2, the related working modes comprise a pure electric forerunner mode, an idle charging mode, a series forerunner mode and an energy recovery mode;

(2.4) when the vehicle speed is more than V2 and less than V1 or the rotating speed is more than N2 and less than N1, carrying out secondary judgment according to the motor temperature, the required torque and the battery residual capacity, determining whether to engage a clutch, and defining the current working mode, wherein the related working modes comprise a pure electric rear-drive mode, a series rear-drive mode, a parallel four-drive mode, a series four-drive mode, a double-motor four-drive mode and an energy recovery mode;

for a four-wheel drive hybrid vehicle, step (2.4) comprises:

2. The control method according to claim 1, wherein for a two-drive hybrid vehicle, if the motor temperature is < T0 or the vehicle speed is < V2 or the rotation speed is < N2, the clutch is disconnected, and a fourth remaining battery capacity S4 is set according to the power supply capacity of the power battery, wherein S4 < S2 < S1;

3. The control method according to claim 1, wherein, for a four-wheel drive hybrid vehicle, if the vehicle speed is < V2 or the motor temperature is < T0 or the rotation speed is < N2, the clutch is disconnected, and the fourth remaining battery capacity S4 is set according to the power supply capacity of the power battery, wherein S4 < S2 < S1:

when the residual battery capacity is greater than S4 and the residual battery capacity is greater than S1, the vehicle enters a pure electric forerunner mode, the power battery supplies power to the forerunner motor, the forerunner motor drives the vehicle, and the activation of energy recovery is not allowed;

when the battery residual capacity is greater than S4 and S1 is greater than the battery residual capacity is greater than S2, the vehicle enters a pure electric forerunner mode, the power battery supplies power to the forerunner motor, and the forerunner motor drives the vehicle to allow the energy recovery to be activated;

when the residual electric quantity of the battery is less than S2, the vehicle enters a series-connection forerunner mode, the forerunner motor drives the vehicle, the oil tank supplies oil to the engine, the engine works to drive the generator to generate electricity, and the generator and the power battery jointly supply power to the forerunner motor.

4. A control device for preventing overheating of a motor of a hybrid vehicle, comprising:

the control unit is used for determining the working mode of the vehicle according to the motor temperature, the required torque and the residual battery capacity and controlling the connection or disconnection of the clutch according to the requirements of different working modes;

wherein, for a two-drive hybrid vehicle, the control unit is configured to perform the steps of:

wherein, for a two-drive hybrid vehicle, step (2.4) comprises:

for a four-wheel drive hybrid vehicle, the control unit is configured to perform the steps of:

for a four-wheel drive hybrid vehicle, step (2.4) comprises:

5. A vehicle control unit comprising the control device for preventing the overheating of the motor of the hybrid vehicle according to claim 4.

6. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 3.