Temperature protection method for electric drive system of four-wheel-drive electric automobile and related equipment

Abstract

The invention belongs to the technical field of electric automobiles, and discloses a four-wheel-drive electric automobile electric drive system temperature protection method and related equipment.According to the method, the water pump gear of a cooling system is dynamically adjusted based on the real-time temperature of a first drive device and the real-time temperature of a second drive device, and the accuracy and intelligence of cooling control are achieved; unnecessary high-power operation of the cooling water pump is effectively avoided, and the energy consumption of the whole vehicle and the maintenance cost of the water pump are reduced; moreover, after the gear of the water pump is switched to the high gear, a torque distribution strategy can be selected and executed according to the current temperature, it is ensured that when the motor is over-temperature, the four-wheel-drive electric vehicle does not directly cut off power, but keeps the running state by adjusting the output torque of the driving device, and therefore the safety and reliability of the electric vehicle are greatly improved, and the service life of the electric vehicle is prolonged. The risk of traffic accidents caused by sudden loss of power is reduced, and the safety of an electric drive system, the whole vehicle and passengers is better guaranteed.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicles, and in particular relates to a temperature protection method for an electric drive system of a four-wheel drive electric vehicle and related equipment. Background Art

[0002] With the continuous advancement of electric vehicle technology, consumers have higher and higher requirements for vehicle performance and safety. Four-wheel drive electric vehicles are gradually gaining favor in the market due to their excellent power performance, handling stability and ability to pass under complex road conditions.

[0003] However, compared with traditional two-wheel drive electric vehicles, which often use a single motor layout with front drive or rear drive, four-wheel drive electric vehicles use dual motor drive, and their electric drive system structure is more complex, which significantly increases the difficulty of thermal management. At present, the application of four-wheel drive dual electric drive solutions in electric vehicles is relatively small, and the corresponding electric drive temperature protection strategy solutions are not comprehensive enough. Specifically, when a temperature fault occurs in the existing four-wheel drive dual electric drive system electric vehicle, the whole vehicle usually directly cuts off the power; although this treatment method can avoid serious damage caused by overheating of the electric drive system to a certain extent, it does not conduct a more detailed analysis and corresponding actions on temperature warnings or faults, and cannot adopt safe and effective driving strategies to ensure the safety of the electric drive system, the whole vehicle and the passengers. In actual driving, sudden power cut-off may cause the vehicle to lose power support, causing traffic accidents such as rear-end collisions, and threatening the life safety of drivers and passengers. Traditional temperature protection strategies often lack accuracy and intelligence when controlling the cooling system. For example, the cooling water pump may continue to run at high power when it is not necessary. This not only increases the power consumption of the water pump, resulting in an increase in the energy consumption of the entire vehicle, but also reduces the reliability of the water pump due to long-term high-load operation, increasing the vehicle's maintenance costs and failure risks.

[0004] It can be seen that the existing temperature protection measures for four-wheel drive electric vehicles usually adopt a method of directly cutting off power when the motor is overheated, resulting in the electric vehicle being unable to operate safely and reliably. Summary of the invention

[0005] The present invention provides a temperature protection method and related equipment for an electric drive system of a four-wheel drive electric vehicle, so as to solve the technical problem that the existing temperature protection measures for four-wheel drive electric vehicles usually adopt a method of directly cutting off power when the motor is overheated, resulting in the electric vehicle being unable to operate safely and reliably.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A temperature protection method for an electric drive system of a four-wheel drive electric vehicle, comprising: Switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; After the water pump gear is switched to the water pump high gear, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device; the torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0007] Furthermore, before switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device, the method further includes: According to the received vehicle start signal, the water pump and fan of the cooling system are controlled to be in the closed state; The real-time temperatures reported by the first driving device and the second driving device are monitored.

[0008] Further, switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device includes: Collecting the real-time temperatures reported by the first driving device and the second driving device, and judging the real-time temperatures of the first driving device and the second driving device; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the first temperature range, the water pump gear is switched to a low water pump gear; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the second temperature range, the water pump gear is switched to the water pump middle gear; If the real-time temperature of the first driving device and / or the real-time temperature of the second driving device are within the third temperature range, the water pump gear is switched to the water pump high gear.

[0009] Further, When the water pump gear is switched to the water pump middle gear, the fan is controlled to start the low speed mode; When the water pump gear is switched to the water pump high gear, the fan is controlled to start the high-speed mode.

[0010] Further, When the water pump gear is switched to the water pump low gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to open; When the water pump gear is switched to the water pump middle gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to be adjusted to a half-open state; When the water pump gear is switched to the water pump high gear, the control straight-through valve is adjusted to a fully open state.

[0011] Furthermore, the real-time temperature of the first drive device is the highest temperature among the first vehicle-mounted power supply and charger two-in-one temperature, the first motor controller temperature and the first reduction device temperature; the real-time temperature of the second drive device is the highest temperature among the second vehicle-mounted power supply and charger two-in-one temperature, the second motor controller temperature and the second reduction device temperature.

[0012] Further, after the water pump gear is switched to the high gear of the cooling system, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device, including: After the water pump gear is switched to the high gear of the cooling system, the current temperature of the first drive device and the current temperature of the second drive device are continuously monitored; Determining the current temperature of the first drive device and the current temperature of the second drive device; If the current temperature of the first drive device is greater than the over-temperature threshold and the current temperature of the second drive device is less than the over-temperature threshold, selecting and executing the first torque distribution strategy; If the current temperature of the first drive device is less than the over-temperature threshold and the current temperature of the second drive device is greater than the over-temperature threshold, selecting and executing the second torque distribution strategy; If the current temperature of the first drive device and the current temperature of the second drive device are both greater than the over-temperature threshold, selecting and executing the third torque distribution strategy; Wherein, the torque distribution strategy includes a first torque distribution strategy, a second torque distribution strategy and a third torque distribution strategy; The first torque distribution strategy is: limiting the output torque of the first drive device to a preset safety limit, and the second drive device compensating the power; The second torque distribution strategy is: limiting the output torque of the second drive device to a preset safety limit, and the first drive device compensating the power; The third torque distribution strategy is: synchronously reducing the output torque of the first drive device and the output torque of the second drive device so that the electric vehicle switches to the limp home mode.

[0013] A temperature protection system for an electric drive system of a four-wheel drive electric vehicle, comprising: A water pump gear switching module, used to switch the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; The distribution strategy execution module is used to select and execute the torque distribution strategy based on the current temperature of the first drive device and the current temperature of the second drive device after the water pump gear is switched to the water pump high gear; the torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0014] A device comprising: Memory for storing computer programs; The processor is used to implement the steps of the temperature protection method of the electric drive system of the four-wheel drive electric vehicle when executing the computer program.

[0015] A computer-readable storage medium stores a computer program, which is used to implement the steps of the temperature protection method for the electric drive system of a four-wheel drive electric vehicle when executed by a processor.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a temperature protection method for an electric drive system of a four-wheel-drive electric vehicle. The method not only dynamically adjusts the water pump gear of a cooling system based on the real-time temperatures of a first drive device and a second drive device, thereby achieving precision and intelligence in cooling control, but also effectively avoiding unnecessary high-power operation of a cooling water pump, thereby reducing energy consumption of the entire vehicle and maintenance costs of the water pump; moreover, after the water pump gear is switched to a high gear, a torque distribution strategy can be selected and executed according to the current temperature, thereby ensuring that the four-wheel-drive electric vehicle will not directly cut off power when the motor is overheated, but maintains the operating state by adjusting the output torque of the drive device, namely, ensuring that the four-wheel-drive electric vehicle can maintain the operating state when the motor temperature rises, thereby greatly improving the safety and reliability of the electric vehicle, reducing the risk of traffic accidents caused by sudden loss of power, and better protecting the safety of the electric drive system, the entire vehicle and the occupants.

[0017] Preferably, in the present invention, the water pump and fan of the cooling system are initialized and controlled when the vehicle is started, and the real-time temperature of the drive device is monitored, which provides a basis for the subsequent temperature protection strategy, ensures that the cooling system can respond quickly when necessary, and improves the response speed and efficiency of the system.

[0018] Preferably, in the present invention, by judging the real-time temperature of the driving device and switching the water pump gear accordingly, refined management of the cooling system is achieved, which not only ensures the cooling effect, but also avoids unnecessary energy consumption and improves the energy efficiency of the system. Preferably, in the present invention, the fan opening mode and speed are controlled according to the switching of the water pump gear, which further enhances the flexibility and response speed of the cooling system and ensures that an effective cooling effect can be provided under different temperature conditions. Preferably, in the present invention, the flow rate of the coolant is controlled by adjusting the opening state of the through valve, thereby further refining the control strategy of the cooling system and improving the cooling efficiency and the stability of the system.

[0019] Preferably, in the present invention, the real-time temperature of the driving device is defined as the highest temperature among the temperatures of multiple key components, which ensures the accuracy and comprehensiveness of temperature monitoring and provides reliable data support for subsequent temperature protection strategies.

[0020] Preferably, in the present invention, after the water pump gear is switched to high gear, different torque distribution strategies are selected and executed according to the current temperature of the two drive devices, ensuring that the electric vehicle can continue to operate when the motor is overheated, while avoiding power loss caused by overheating of a single motor, thereby improving the driving safety and stability of the electric vehicle. In addition, by limiting the output torque of the overheated motor and compensating the power by other motors, or synchronously reducing the output torque of the two motors to switch to limp mode, the method also provides a variety of strategies for dealing with motor overheating, enhancing the flexibility and adaptability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of temperature arrangement information of a drive device is provided for an embodiment of the present invention; Figure 2 A schematic diagram of a cooling system for a vehicle drive device provided in an embodiment of the present invention; Figure 3 A flow chart of a temperature protection method for an electric drive system of a four-wheel drive electric vehicle provided by an embodiment of the present invention; Figure 4 A flow chart of a temperature protection method for an electric drive system of a four-wheel drive electric vehicle provided by the present invention; Figure 5 A schematic structural diagram of a temperature protection system for an electric drive system of a four-wheel drive electric vehicle provided by the present invention. DETAILED DESCRIPTION

[0022] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0023] The following is an explanation of the technical terms involved in the present invention: DCDC / OBC: A two-in-one device that combines an onboard power supply and a charger. DCDC (Direct Current - Direct Current) is a DC-DC converter that converts a fixed DC voltage into a variable DC voltage. In electric vehicles, it is often used to convert the voltage of a high-voltage battery into a low-voltage DC power suitable for onboard electronic equipment. OBC (On-Board Charger) is an onboard charger that converts AC power in the power grid into DC power to charge the power battery of an electric vehicle. "DCDC / OBC" means that these two functions are integrated into one device.

[0024] MCU: Motor Control Unit. It is the core control component of the electric drive system of electric vehicles, responsible for controlling the speed, torque, steering and other operating states of the drive motor. By receiving instructions from the vehicle controller and feedback signals from the motor, the MCU accurately adjusts the input voltage, current and frequency of the motor to meet the needs of different driving conditions of the vehicle.

[0025] MOT: Motor. In electric vehicles, the motor is a key component that converts electrical energy into mechanical energy and provides power for the vehicle. It operates according to the control signal of the motor controller to drive the vehicle forward, backward or accelerate, etc.

[0026] REDUT: Reduction Gear Unit. Since the speed of the drive motor is usually high, but the output torque is relatively small, and the vehicle needs appropriate torque and speed to travel. The function of the reduction gear unit is to reduce the speed of the drive motor and increase the output torque to meet the power requirements of the vehicle under different driving conditions.

[0027] As described in the background technology, when a temperature fault occurs in an existing four-wheel drive dual-electric drive system electric vehicle, the procedure usually adopted by the entire vehicle is to directly cut off the power, without taking corresponding actions for temperature warnings or faults and adopting safe and effective driving strategies to ensure the safety of the electric drive system, the entire vehicle and the passengers.

[0028] Example 1 In order to solve the above problems, the present embodiment provides a temperature protection method for the electric drive system of a four-wheel drive electric vehicle. The method is used to dynamically adjust the performance output of the front drive device or the rear drive device according to the temperature alarm or temperature fault phenomenon of the front drive device or the rear drive device in the four-wheel drive; at the same time, the scheme also proposes a scheme to ensure the driving of the vehicle, and proposes a problem of power cutting during the driving of the whole vehicle due to temperature fault, thereby improving the safety of the whole vehicle.

[0029] This embodiment provides a temperature protection method for an electric drive system of a four-wheel drive electric vehicle, comprising: Switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; After the water pump gear is switched to the water pump high gear, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device; the torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0030] The control method provided by this embodiment is further explained below in conjunction with the accompanying drawings: The core technology on which this embodiment is based is: First, integrated drive device: Integrate the vehicle power supply (DCDC / OBC), motor controller (MCU), drive motor (MOT) and reduction device (REDUT) into a single module, collect the temperature of each sub-component in real time, and use the highest temperature as the basis for over-temperature judgment. Figure 1 As shown, the real-time temperature of the first drive device is the highest temperature among the temperature of the first on-board power supply and charger two-in-one (DCDC / OBC1), the temperature of the first motor controller (MCU1) and the temperature of the first reduction device (REDUT1); the real-time temperature of the second drive device is the highest temperature among the temperature of the second on-board power supply and charger two-in-one (DCDC / OBC2), the temperature of the second motor controller (MCU2) and the temperature of the second reduction device (REDUT2).

[0031] Second, graded cooling control: dynamically adjust the water pump power and fan start and stop according to the temperature threshold range (low temperature, medium temperature, high temperature), optimize the coolant flow rate, and reduce energy consumption.

[0032] Third, dynamic torque distribution: When a drive unit is overheated, its output torque is limited and the power of another drive unit is increased to maintain the power of the entire vehicle and avoid driving interruptions.

[0033] Among them, Figure 2 As shown, the cooling system of the drive device includes: a cooling fan, a water pump, a first through valve and a second through valve. The first drive device includes DCDC / OBC1 (first vehicle power supply and charger two-in-one), MCU1 (first motor controller), MOT1 (first drive motor), REDUT1 (first reduction gear); the second drive device includes DCDC / OBC2 (second vehicle power supply and charger two-in-one), MCU2 (second motor controller), MOT2 (second drive motor), REDUT2 (second reduction gear); the coolant flows through DCDC / OBC→MCU→MOT in sequence to achieve efficient heat dissipation.

[0034] The first driving device and the second driving device both operate independently and report temperature data in real time.

[0035] This embodiment provides a temperature protection method for an electric drive system of a four-wheel drive electric vehicle, comprising: Starting phase: When the vehicle enters the Ready state, the water pump and fan remain closed and the coolant does not circulate.

[0036] Temperature monitoring: Drive device 1 and drive device 2 report the temperature of each sub-component in real time, and the highest temperature is taken as the judgment basis.

[0037] Staged cooling control: Low - temperature range (T < T1): The water pump operates at low gear, the direct - through valve is closed, and the coolant only maintains the basic circulation.

[0038] Medium - temperature range (T1 ≤ T < T2): The water pump operates at medium gear, the fan starts in low - speed mode to increase the coolant flow rate.

[0039] High - temperature range (T ≥ T2): The water pump operates at high gear, the fan switches to high - speed mode, the direct - through valve is fully open, and the coolant flow rate is maximized.

[0040] Dynamic torque distribution: Single - drive device over - temperature (T ≥ T2): Limit the output torque of the over - temperature device to the safety limit value, and the other drive device compensates for the power.

[0041] Dual - drive device over - temperature (T ≥ T2): Synchronously reduce the torque of both, and switch to the "limp - home mode" to ensure the vehicle can drive safely at low speed.

[0042] As Figure 3 shown, as a further preferred solution of this embodiment, the specific implementation steps are as follows: Startup and initial state: When the whole vehicle starts, neither the water pump nor the fan is turned on. After the vehicle runs for a period of time, drive device 1 and drive device 2 respectively report the temperatures of their sub - components in real time.

[0043] Cooling system control strategy: According to the temperature rise range where the highest temperature reported by the first drive device and the second drive device is located, perform corresponding actions. When the temperature is in the low - temperature zone (i.e., T1 ≤ the temperature of the first drive device < T2 or T1 ≤ the temperature of the second drive device < T2), the water pump is turned on; as the temperature rises, when T2 ≤ the temperature of the first drive device < T3 or T2 ≤ the temperature of the second drive device < T3, the water pump is turned on at medium gear and the fan is turned on at low gear; when T3 ≤ the temperature of the first drive device or T3 ≤ the temperature of the second drive device, the water pump is turned on at high gear.

[0044] Torque distribution strategy: After the water pump is turned on at high gear, enter the torque distribution strategy. At this time, it is determined that the temperature of the first drive device is greater than T3 and the temperature of the second drive device is less than T3. If this condition is met, the first drive device enters the first torque distribution strategy, and the first torque distribution strategy is the external characteristic of the temperature protection output limit value of the first drive device; If this condition is not met, then it is judged that the temperature of the second drive device is greater than T3 and the temperature of the first drive device is less than T3. When this condition is met, the second drive device enters the second torque distribution strategy, and the second torque distribution strategy is the external characteristic of the temperature protection output limit value of the second drive device; If the above conditions are not met, the first drive device and the second drive device enter the third torque distribution strategy, which is the minimum protection strategy for safe driving formulated by the first drive device and the second drive device according to the temperature fault strategy, ensuring that the vehicle can drive normally and no temperature protection will continue to occur, and reaching the natural temperature balance limit of the first drive device and the second drive device. Of course, the execution order of the above three determination steps can be interchangeable or performed simultaneously.

[0045] Example 2 This embodiment provides a temperature protection method for the electric drive system of a four-wheel drive electric vehicle. This protection method is used for temperature protection under normal driving conditions on urban roads. The specific implementation process is as follows: Vehicle startup phase: Assuming that the vehicle is started in an urban road environment, the vehicle is in a ready state. According to the temperature protection method of the present invention, the water pump is not turned on, the fan is not turned on, and the first through valve and the second through valve in the cooling water circuit are not turned on during startup. When the vehicle starts to travel, the first drive device and the second drive device start to work and report the temperature of their sub-components in real time.

[0046] Temperature rise and cooling system start-up: During normal driving on urban roads, the temperature of the first drive unit and the second drive unit gradually rises due to frequent acceleration and deceleration. When the temperature of the first drive unit reaches T1 (assuming T1=40℃), and satisfies T1≤first drive unit temperature<T2 (assuming T2=50℃), and the temperature of the second drive unit is still lower than T1, the water pump is turned on according to the protection strategy. At this time, the water pump runs at low power, and the coolant begins to circulate in the cooling water circuit to cool the first drive unit. As the vehicle continues to drive, the temperature of the first drive unit and the second drive unit continues to rise. When the temperature of the first drive unit reaches T2 (50℃), and the temperature of the second drive unit also reaches T2 (assuming that the temperature of the second drive unit is 50℃ at this time), and satisfies T2≤first drive unit temperature<T3 (assuming T3=60℃) or T2≤second drive unit temperature<T3, the water pump is turned on at mid-gear and the fan is turned on at low gear. At this time, the cooling capacity of the cooling system is further enhanced, the cooling flow to the first drive unit and the second drive unit is increased, and the temperature rise rate is effectively controlled.

[0047] Temperature approaches the upper limit and torque distribution strategy: If the vehicle travels on a congested road for a long time, the temperature of the first drive unit continues to rise and reaches T3 (60°C), while the temperature of the second drive unit is 55°C, satisfying T3≤first drive unit temperature and second drive unit temperature<T3. At this time, the water pump high gear is turned on and the torque distribution strategy is entered. According to the strategy, the first drive unit enters torque distribution strategy 1, that is, the first drive unit adjusts the torque output according to its temperature protection output limit characteristics. At this time, the first drive unit will appropriately reduce the torque output to reduce its own heat generation, while ensuring that the vehicle can still maintain a certain driving speed in an urban road environment. During this process, the second drive unit continues to work normally to maintain the power output balance of the vehicle and ensure safe driving of the vehicle.

[0048] Example 3 This embodiment provides a temperature protection method for the electric drive system of a four-wheel drive electric vehicle. This protection method is used for temperature protection under high-speed driving conditions. The specific implementation process is as follows: Initial stage of high-speed driving: The vehicle is driving at a high speed on the highway. In the startup stage, the water pump, fan and through valve are not turned on. As the driving time increases, the temperature of the first drive unit and the second drive unit rises rapidly under high-speed operation. When the temperature of the first drive unit and the second drive unit reaches T1 (40°C) at the same time, the water pump is turned on and runs at low power to initially cool the drive unit.

[0049] Rapid temperature rise and cooling system strengthening: Due to the large motor load at high speed, the temperature of the first drive unit and the second drive unit rises rapidly. Soon, the temperature of both drive units reaches T2 (50°C), at which time the water pump is turned on at mid-gear and the fan is turned on at low gear to increase the cooling flow. However, the vehicle continues to drive at high speed, and the temperature of the first drive unit first reaches T3 (60°C), followed by the temperature of the second drive unit. At this time, the water pump is turned on at high gear and the torque distribution strategy is entered.

[0050] Torque distribution and safe driving of the vehicle: Because the temperature of the first drive unit and the second drive unit is greater than T3, the first drive unit and the second drive unit enter torque distribution strategy 3. Under torque distribution strategy 3, the first drive unit and the second drive unit adjust the torque according to the minimum protection strategy for safe driving formulated by the temperature fault strategy. The two drive units reduce the torque output at the same time, but maintain a certain power output level, so that the vehicle can drive safely at a relatively low speed on the highway, avoiding serious failures caused by excessive temperature, and also preventing safety accidents caused by sudden power cut-off. In this process, the vehicle speed may drop from the original 120km / h to about 80km / h, but it can still ensure the safe driving of the vehicle on the highway until the vehicle drives to the service area or the temperature drops to a safe range.

[0051] It can be seen that in practical applications, different vehicle driving conditions (such as climbing, rapid acceleration, rapid deceleration, etc.) will cause different temperature changes in the drive device. The temperature protection method of this embodiment can accurately control the cooling system and adjust the torque output of the drive device according to the real-time temperature conditions, ensuring the safe and stable operation of the electric drive system of the four-wheel drive electric vehicle under various complex conditions, and effectively improving the performance and safety of the vehicle. At the same time, by reasonably controlling the operation of the water pump and fan, the energy consumption of the whole vehicle is reduced, the reliability of related components is improved, and strong technical support is provided for the development of four-wheel drive electric vehicles.

[0052] Example 4 like Figure 4 As shown, this embodiment provides a temperature protection method for an electric drive system of a four-wheel drive electric vehicle, comprising the following steps: Switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; After the water pump gear is switched to the water pump high gear, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device; the torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0053] In this embodiment, before switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device, the method further includes: According to the received vehicle start signal, the water pump and fan of the cooling system are controlled to be in the closed state; The real-time temperatures reported by the first driving device and the second driving device are monitored.

[0054] In this embodiment, switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device includes: Collecting the real-time temperatures reported by the first driving device and the second driving device, and judging the real-time temperatures of the first driving device and the second driving device; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the first temperature range, the water pump gear is switched to a low water pump gear; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the second temperature range, the water pump gear is switched to the water pump middle gear; If the real-time temperature of the first driving device and / or the real-time temperature of the second driving device are within the third temperature range, the water pump gear is switched to the water pump high gear.

[0055] In this implementation, when the water pump gear is switched to the water pump middle gear, the fan is controlled to start the low speed mode; When the water pump gear is switched to the water pump high gear, the fan is controlled to start the high-speed mode.

[0056] In this embodiment, when the water pump gear is switched to the water pump low gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to open; When the water pump gear is switched to the water pump middle gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to be adjusted to a half-open state; When the water pump gear is switched to the water pump high gear, the control straight-through valve is adjusted to a fully open state.

[0057] In this embodiment, the real-time temperature of the first drive device is the highest temperature among the first vehicle power supply and charger two-in-one temperature, the first motor controller temperature and the first reduction device temperature; the real-time temperature of the second drive device is the highest temperature among the second vehicle power supply and charger two-in-one temperature, the second motor controller temperature and the second reduction device temperature.

[0058] In this implementation, after the water pump gear is switched to the high gear of the cooling system, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device, including: After the water pump gear is switched to the high gear of the cooling system, the current temperature of the first drive device and the current temperature of the second drive device are continuously monitored; Determining the current temperature of the first drive device and the current temperature of the second drive device; If the current temperature of the first drive device is greater than the over-temperature threshold and the current temperature of the second drive device is less than the over-temperature threshold, selecting and executing the first torque distribution strategy; If the current temperature of the first drive device is less than the over-temperature threshold and the current temperature of the second drive device is greater than the over-temperature threshold, selecting and executing the second torque distribution strategy; If the current temperature of the first drive device and the current temperature of the second drive device are both greater than the over-temperature threshold, selecting and executing the third torque distribution strategy; Wherein, the torque distribution strategy includes a first torque distribution strategy, a second torque distribution strategy and a third torque distribution strategy; The first torque distribution strategy is: limiting the output torque of the first drive device to a preset safety limit, and the second drive device compensating the power; The second torque distribution strategy is: limiting the output torque of the second drive device to a preset safety limit, and the first drive device compensating the power; The third torque distribution strategy is: synchronously reducing the output torque of the first drive device and the output torque of the second drive device so that the electric vehicle switches to the limp home mode.

[0059] like Figure 5 As shown, the present embodiment also provides a temperature protection system for the electric drive system of a four-wheel drive electric vehicle, including: a water pump gear switching module, used to switch the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; an allocation strategy execution module, used to select and execute a torque allocation strategy based on the current temperature of the first drive device and the current temperature of the second drive device after the water pump gear is switched to a high gear of the water pump; the torque allocation strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0060] The present invention also provides a device, comprising: a memory for storing a computer program; and a processor for implementing the steps of the temperature protection method for the electric drive system of a four-wheel drive electric vehicle when executing the computer program.

[0061] When the processor executes the computer program, the steps of temperature protection of the electric drive system of the four-wheel drive electric vehicle are implemented, for example: based on the real-time temperature of the first drive device and the real-time temperature of the second drive device, the water pump gear of the cooling system is switched; after the water pump gear is switched to the water pump high gear, based on the current temperature of the first drive device and the current temperature of the second drive device, a torque distribution strategy is selected and executed; the torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0062] Alternatively, the processor implements the functions of each module in the above-mentioned system when executing the computer program, for example: a water pump gear switching module, which is used to switch the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; an allocation strategy execution module, which is used to select and execute the torque allocation strategy based on the current temperature of the first drive device and the current temperature of the second drive device after the water pump gear is switched to the water pump high gear; the torque allocation strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0063] Exemplarily, the computer program can be divided into one or more modules / units, and the one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments that can complete the preset functions, and the instruction segments are used to describe the execution process of the computer program in the temperature protection device of the electric drive system of the four-wheel drive electric vehicle. For example, the computer program can be divided into a water pump gear switching module and an allocation strategy execution module; the specific functions of each module are as follows: a water pump gear switching module, which is used to switch the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; an allocation strategy execution module, which is used to select and execute a torque distribution strategy based on the current temperature of the first drive device and the current temperature of the second drive device after the water pump gear is switched to the water pump high gear; the torque distribution strategy is used to control the output torque of the first drive device or / and the second drive device so that the four-wheel drive electric vehicle is always in operation.

[0064] The temperature protection device of the electric drive system of the four-wheel drive electric vehicle can be a computing device such as a desktop computer, a notebook, a PDA and a cloud server. The temperature protection device of the electric drive system of the four-wheel drive electric vehicle may include, but is not limited to, a processor and a memory. Those skilled in the art will understand that the above is an example of a temperature protection device of the electric drive system of a four-wheel drive electric vehicle, and does not constitute a limitation on the temperature protection device of the electric drive system of a four-wheel drive electric vehicle. It may include more components than the above, or a combination of certain components, or different components. For example, the temperature protection device of the electric drive system of the four-wheel drive electric vehicle may also include input and output devices, network access devices, buses, etc.

[0065] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The processor is the control center of the temperature protection of the electric drive system of the four-wheel drive electric vehicle, and uses various interfaces and lines to connect various parts of the temperature protection device of the electric drive system of the four-wheel drive electric vehicle.

[0066] The memory can be used to store the computer program and / or module, and the processor implements various functions of the temperature protection device of the electric drive system of the four-wheel drive electric vehicle by running or executing the computer program and / or module stored in the memory and calling the data stored in the memory.

[0067] The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0068] The present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the temperature protection method for the electric drive system of a four-wheel drive electric vehicle are implemented.

[0069] If the module / unit integrated in the temperature protection system of the electric drive system of the four-wheel drive electric vehicle is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0070] Based on such understanding, the present invention implements all or part of the processes in the temperature protection method of the electric drive system of the four-wheel drive electric vehicle, and can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, the steps of the temperature protection method of the electric drive system of the four-wheel drive electric vehicle can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or preset intermediate form, etc.

[0071] The computer-readable storage medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0072] It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electrical carrier signals and telecommunication signals.

[0073] The present invention provides a temperature protection method for an electric drive system of a four-wheel drive electric vehicle, which has the following advantages: First, safety is improved: Compared with the traditional method of directly cutting off power when the motor is overheated, the present invention can ensure the safe and reliable operation of the vehicle when the temperature of the electric drive system is abnormal by dynamically adjusting the performance output of the fan, water pump and dual drive device. According to different temperature fault conditions, the torque output of the drive device is reasonably adjusted to avoid safety accidents caused by sudden loss of power of the vehicle, providing a safer driving environment for drivers and passengers.

[0074] Second, clear logic and reduced hidden dangers: The protection method of the present invention has clear logic and simple strategy, which greatly reduces the risk of the vehicle losing power or other safety hazards due to temperature warnings or failures caused by failure of the drive device. Through clear temperature range judgment and corresponding action execution, it can quickly and accurately deal with the temperature problem of the electric drive system, ensuring that the vehicle is always in a safe operating state.

[0075] Third, energy consumption reduction and reliability improvement: The protection method of the present invention greatly reduces the power consumption of the water pump and the energy consumption of the whole vehicle by accurately controlling the operating power of the water pump. At the same time, due to the reduction of the power consumption of the water pump, its workload is reduced, the reliability of the water pump is improved to a certain extent, the maintenance cost and failure probability of the vehicle are reduced, and the overall performance of the vehicle is improved.

[0076] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A temperature protection method for an electric drive system of a four-wheel drive electric vehicle, characterized in that: include: Switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; If the water pump gear is switched to the water pump high gear, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device; The torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in a running state.

2. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 1, characterized in that: Before switching the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device, the method further includes: According to the received vehicle start signal, the water pump and fan of the cooling system are controlled to be in the closed state; The real-time temperatures reported by the first driving device and the second driving device are monitored.

3. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 1, characterized in that: The step of switching the water pump gear of the cooling system based on the real-time temperature of the first driving device and the real-time temperature of the second driving device comprises: Collecting the real-time temperatures reported by the first driving device and the second driving device, and judging the real-time temperatures of the first driving device and the second driving device; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the first temperature range, the water pump gear is switched to a low water pump gear; If the real-time temperature of the first drive device and / or the real-time temperature of the second drive device is within the second temperature range, the water pump gear is switched to the water pump middle gear; If the real-time temperature of the first driving device and / or the real-time temperature of the second driving device are within the third temperature range, the water pump gear is switched to the water pump high gear.

4. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 3, characterized in that: When the water pump gear is switched to the water pump middle gear, the fan is controlled to start the low speed mode; When the water pump gear is switched to the water pump high gear, the fan is controlled to start the high-speed mode.

5. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 3, characterized in that: When the water pump gear is switched to the water pump low gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to open; When the water pump gear is switched to the water pump middle gear, the through valve corresponding to the first driving device and / or the second driving device is controlled to be adjusted to a half-open state; When the water pump gear is switched to the water pump high gear, the control straight-through valve is adjusted to a fully open state.

6. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 1, characterized in that: The real-time temperature of the first drive device is the highest temperature among the first vehicle-mounted power supply and charger two-in-one temperature, the first motor controller temperature and the first reduction device temperature; the real-time temperature of the second drive device is the highest temperature among the second vehicle-mounted power supply and charger two-in-one temperature, the second motor controller temperature and the second reduction device temperature.

7. The temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to claim 1, characterized in that: After the water pump gear is switched to the high gear of the cooling system, the torque distribution strategy is selected and executed based on the current temperature of the first drive device and the current temperature of the second drive device, including: After the water pump gear is switched to the high gear of the cooling system, the current temperature of the first drive device and the current temperature of the second drive device are continuously monitored; Determining the current temperature of the first drive device and the current temperature of the second drive device; If the current temperature of the first drive device is greater than the over-temperature threshold and the current temperature of the second drive device is less than the over-temperature threshold, selecting and executing the first torque distribution strategy; If the current temperature of the first drive device is less than the over-temperature threshold and the current temperature of the second drive device is greater than the over-temperature threshold, selecting and executing the second torque distribution strategy; If the current temperature of the first drive device and the current temperature of the second drive device are both greater than the over-temperature threshold, selecting and executing the third torque distribution strategy; Wherein, the torque distribution strategy includes a first torque distribution strategy, a second torque distribution strategy and a third torque distribution strategy; The first torque distribution strategy is: limiting the output torque of the first drive device to a preset safety limit, and the second drive device compensating the power; The second torque distribution strategy is: limiting the output torque of the second drive device to a preset safety limit, and the first drive device compensating the power; The third torque distribution strategy is: synchronously reducing the output torque of the first drive device and the output torque of the second drive device so that the electric vehicle switches to the limp home mode.

8. A temperature protection system for a four-wheel drive electric vehicle electric drive system, characterized in that: include: A water pump gear switching module, used to switch the water pump gear of the cooling system based on the real-time temperature of the first drive device and the real-time temperature of the second drive device; A distribution strategy execution module, for selecting and executing a torque distribution strategy based on a current temperature of the first drive device and a current temperature of the second drive device after the water pump gear is switched to a water pump high gear; The torque distribution strategy is used to control the output torque of the first drive device and / or the second drive device so that the four-wheel drive electric vehicle is always in a running state.

9. A device, characterized in that: include: Memory for storing computer programs; A processor is used to implement the steps of the temperature protection method for the electric drive system of a four-wheel drive electric vehicle according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, it is used to implement the steps of the temperature protection method of the electric drive system of a four-wheel drive electric vehicle according to any one of claims 1 to 7.

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