Oil-cooled electric drive assembly for electric vehicle, and oil leakage detection strategy for oil-cooled electric drive assembly

Abstract

The present invention relates to the field of electric vehicles. Disclosed are an oil-cooled electric drive assembly for an electric vehicle, and an oil leakage detection strategy for an oil-cooled electric drive assembly. The detection strategy comprises: first, determining whether an enabling condition for oil leakage detection is met; when the enabling condition is met, controlling an oil pump of an electric vehicle to operate at a preset rotation speed; determining whether an end flag has been received; when the end flag has not been received, determining a first cumulative time; on the basis of a comparison between the first cumulative time and a preset time, determining that no oil leakage occurs; and on the basis of other flags, determining other oil leakage situations. In the detection strategy, oil in an oil chamber of an oil pump can be diagnosed by means of an electric motor and the oil pump, without adding an oil level sensor; oil leakage detection is enabled on the basis of a preset condition; at the same time, the phase current of the oil pump is measured; and whether a dry-run fault has occurred in the oil pump is determined on the basis of the magnitude of the phase current. Compared with a means in which an oil leakage prevention pipe is additionally provided, the detection strategy can reduce costs, and enables real-time detection so as to actively identify the occurrence of oil leakage, thereby ensuring the operation safety of electric vehicles.

Description

Oil-cooled electric drive assembly for electric vehicles and its oil leak detection strategy Technical Field

[0001] This invention relates to the field of electric vehicles, and more specifically to an oil-cooled electric drive assembly for electric vehicles and its oil leakage detection strategy. Background Technology

[0002] Electric vehicles use electricity stored in batteries as their energy source, offering advantages such as high efficiency, energy saving, low noise, and zero emissions. They possess unparalleled advantages in energy conservation and environmental protection, thus gradually becoming a significant development trend in the automotive industry. Oil-cooled electric drive systems, a crucial component of electric vehicles, include a motor controller, oil-cooled motor, reducer, and oil pump, among other oil-cooled accessories. Cooling oil is stored within the reducer; leaks not only affect the cooling of the motor and reducer but can also contaminate surrounding components, potentially posing a fire hazard. Traditional methods for detecting oil levels involve adding an oil level sensor, but this is difficult to implement in complex oil-cooled electric drives and requires additional hardware circuitry on the motor controller, making it disadvantageous in terms of cost and space. Existing technologies include built-in oil channels or leak-proof sleeves to reduce the risk of leaks by eliminating external piping. However, these are all mechanical structural optimizations and lack proactive diagnosis of leak events. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides an oil-cooled electric drive assembly for electric vehicles and its oil leakage detection strategy. This detection strategy can diagnose the oil in the oil pump chamber through the motor and oil pump without adding an oil level sensor, and determine whether an oil leak has occurred based on the performance of the oil pump. Compared with using an oil level sensor or adding an anti-leakage pipeline, this method can reduce costs and space occupancy, and can detect and actively identify oil leaks in real time, thus ensuring the safety of electric vehicle operation.

[0004] To achieve the above objectives, the present invention provides an oil leakage detection strategy for an oil-cooled electric drive assembly of an electric vehicle, the electric vehicle including a motor and an oil pump, the detection strategy comprising:

[0005] Determine if the conditions for activating the oil leak detection are currently met;

[0006] If the activation conditions are met, control the oil pump of the electric vehicle to a preset speed;

[0007] Determine whether the end flag from the oil pump feedback has been received;

[0008] If the end flag is not currently received, determine a first cumulative time during which the end flag has not been received;

[0009] Determine whether the first cumulative time is greater than or equal to a preset first time threshold;

[0010] If the first cumulative time is greater than or equal to a preset first time threshold, it is determined that there is no oil leakage.

[0011] Preferably, determining whether the current conditions for activating oil leak detection are met includes:

[0012] Determine whether the oil pump has reported any faults before it is started;

[0013] If no fault is reported before the oil pump is turned on, determine whether the speed of the electric vehicle is between the preset first minimum speed and the first maximum speed, whether the temperature of the cooling oil of the oil pump is between the preset first minimum temperature and the first maximum temperature, and whether the absolute value of the driving gradient of the electric vehicle is less than the preset first gradient.

[0014] When the vehicle speed of the electric vehicle is between a preset first minimum speed and a preset first maximum speed, the oil temperature of the cooling oil in the oil pump is between a preset first minimum temperature and a preset first maximum temperature, and the absolute value of the driving gradient of the electric vehicle is within a preset first gradient, it is determined that the current conditions for opening the oil leak detection are met.

[0015] Preferably, when it is determined that the opening conditions are currently met, controlling the vehicle's oil pump to a preset speed includes:

[0016] After the oil pump reaches a preset speed, phase current is detected and it is determined whether the second cumulative time of the oil pump operation is greater than or equal to a preset second time threshold, and the first time threshold is greater than the second time threshold.

[0017] If the second cumulative time of the oil pump operation is greater than or equal to a preset second time threshold, the oil pump will output the end flag.

[0018] Determine whether a vacuum failure has occurred based on the phase current;

[0019] In the event of a vacuum failure, the oil pump will report a vacuum failure flag, stop the phase current detection, and reset the second cumulative time to zero.

[0020] In the absence of a vacuum failure, the oil pump stops the phase current detection and resets the second cumulative time to zero.

[0021] Preferably, determining whether an end flag has been received from the oil pump includes:

[0022] Determine whether the current termination condition is met;

[0023] If the aforementioned termination conditions are met, the oil leak detection operation is terminated, and the first accumulated time is cleared.

[0024] Preferably, determining whether an oil pump feedback end flag has been received includes:

[0025] Determine if an oil pump cavitation fault indicator has been received.

[0026] If no cavitation fault indicator is received from the oil pump, it is determined that there is no oil leak;

[0027] Upon receiving a feedback alarm from the oil pump indicating a vacuum fault, an oil leak is confirmed.

[0028] Preferably, determining whether the current termination condition is met includes:

[0029] Determine whether the oil pump reports a fault during oil leak detection;

[0030] If a fault is reported when the oil pump is performing an oil leak detection, it is determined that the termination condition is met; it is determined whether the speed of the electric vehicle is less than the preset second minimum speed or greater than the second maximum speed, wherein the second minimum speed is less than the first minimum speed and the second maximum speed is greater than the first maximum speed.

[0031] If the speed of the electric vehicle is less than the preset second minimum speed or greater than the second maximum speed, it is determined that the termination condition is met.

[0032] Preferably, determining whether the current termination condition is met includes:

[0033] Determine whether the temperature of the cooling oil in the oil pump is less than a preset second minimum temperature or greater than a preset second maximum temperature, wherein the second minimum temperature is less than the first minimum temperature and the second maximum temperature is greater than the first maximum temperature.

[0034] If the temperature of the cooling oil in the oil pump is less than the preset second minimum temperature or greater than the second maximum temperature, the termination condition is determined to be met.

[0035] Preferably, determining whether the current termination condition is met includes:

[0036] Determine whether the absolute value of the driving gradient of the electric vehicle is greater than a preset second gradient, and whether the second gradient is greater than the first gradient;

[0037] If the absolute value of the driving gradient of the electric vehicle is greater than the preset second gradient, it is determined that the termination condition is met.

[0038] Preferably, the electric vehicle acquires the oil leak detection information only once per driving cycle.

[0039] A second aspect of the present invention provides an oil-cooled electric drive assembly for an electric vehicle, the oil-cooled electric drive assembly comprising:

[0040] Motor controller;

[0041] An oil-cooled motor, wherein the oil-cooled motor is electrically connected to the motor controller;

[0042] The speed reducer is connected to the oil-cooled motor.

[0043] An oil pump, the oil pump pipeline being connected to the oil-cooled motor and the reducer;

[0044] The motor controller is used to execute any of the detection strategies described above.

[0045] Through the above technical solution, this detection strategy can diagnose the oil in the oil pump's oil chamber through the motor and oil pump without adding an oil level sensor. It can activate oil leakage detection according to preset conditions, and at the same time, the oil pump performs phase current detection. After detection, the oil pump can determine whether a cavitation fault has occurred based on the magnitude of the phase current. Compared with setting an oil level sensor or adding an anti-leakage pipeline, it can reduce costs and space occupation, and can detect and actively identify oil leakage in real time, thus ensuring the safety of electric vehicle operation. Attached Figure Description

[0046] Figure 1 is a flowchart of an oil leakage detection strategy for an oil-cooled electric drive assembly of an electric vehicle according to an embodiment of the present invention;

[0047] Figure 2 is a schematic block diagram of the oil leak detection activation condition of an oil leak detection strategy for an oil-cooled electric drive assembly of an electric vehicle according to an embodiment of the present invention.

[0048] Figure 3 is a schematic block diagram of the oil pump feedback flag condition of an oil-cooled electric drive assembly oil leakage detection strategy for an electric vehicle according to an embodiment of the present invention.

[0049] Figure 4 is a schematic block diagram of the oil leakage situation discrimination of an oil-cooled electric drive assembly oil leakage detection strategy for an electric vehicle according to an embodiment of the present invention.

[0050] Figure 5-8 is a schematic block diagram of the oil leak detection termination condition of an oil leak detection strategy for an oil-cooled electric drive assembly of an electric vehicle according to an embodiment of the present invention. Detailed Implementation

[0051] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0052] Figure 1 shows a flowchart of an oil leakage detection strategy for an oil-cooled electric drive assembly of an electric vehicle according to an embodiment of the present invention.

[0053] An electric vehicle includes a set of motors and a set of oil pumps. As shown in Figure 1, the detection strategy may include the following steps:

[0054] In step S10, it is determined whether the conditions for activating the oil leak detection are met.

[0055] In step S11, if it is determined that the opening conditions are met, the oil pump of the electric vehicle is controlled to a preset speed;

[0056] In step S12, it is determined whether an end flag has been received from the oil pump feedback.

[0057] In step S13, if no end flag is currently received, the first cumulative time for not receiving the end flag is determined;

[0058] In step S14, it is determined whether the first cumulative time is greater than or equal to a preset first time threshold.

[0059] In step S15, if the first cumulative time is greater than or equal to a preset first time threshold, it is determined that there is no oil leakage.

[0060] In Figure 1, step S10 first determines whether the conditions for starting the oil leak detection are met based on data such as the current vehicle speed and oil temperature of the electric vehicle.

[0061] In step S11, when the electric vehicle meets the opening conditions, the oil pump is adjusted to reach the preset speed.

[0062] Step S12 determines whether an end flag has been received from the oil pump.

[0063] Step S13: If no end flag is received at present, determine the first cumulative time during which no end flag has been received;

[0064] Step S14 determines whether the first cumulative time is greater than or equal to the preset first time threshold;

[0065] Step S15 determines that there is no oil leakage if the first cumulative time is greater than or equal to the preset first time threshold.

[0066] This detection strategy, without adding an oil level sensor, can diagnose the oil level in the oil pump's oil chamber through the motor and oil pump. It can activate oil leakage detection based on preset conditions and simultaneously detect the phase current of the oil pump. After detection, the oil pump can determine whether a cavitation fault has occurred based on the magnitude of the phase current. Compared with setting an oil level sensor or adding an anti-leakage pipeline, this approach reduces costs and space occupancy, enables real-time detection, and proactively identifies oil leakage, thus ensuring the safety of electric vehicle operation.

[0067] Figure 2 is a schematic block diagram of the oil leak detection activation condition of an oil-cooled electric drive assembly oil leak detection strategy for an electric vehicle according to an embodiment of the present invention.

[0068] In Figure 2, considering the activation conditions that need to be met when the electric vehicle starts the oil leak detection, it is necessary to determine whether the activation conditions of the oil leak detection are met at present. Feedback is required based on the current vehicle condition. In one embodiment of the present invention, step S20 determines whether the oil pump has reported a fault before starting. If the oil pump has a problem, subsequent phase current detection cannot be performed. Therefore, it is necessary to determine whether the oil pump has reported a fault before starting.

[0069] Step S21: If no fault is reported before the oil pump is turned on, determine whether the electric vehicle's speed is between a preset first minimum speed and a preset first maximum speed, whether the oil pump's cooling oil temperature is between a preset first minimum temperature and a preset first maximum temperature, and whether the absolute value of the electric vehicle's driving gradient is less than a preset first gradient. Multiple conditions must coexist for the activation condition to be met.

[0070] In step S22, the electric vehicle only meets the activation conditions when its speed is between the preset first minimum speed and the preset first maximum speed, the oil temperature of the oil pump's cooling oil is between the preset first minimum temperature and the preset first maximum temperature, and the absolute value of the electric vehicle's driving gradient is within the preset first gradient.

[0071] Figure 3 is a schematic block diagram illustrating the determination of the oil pump feedback flag in an oil-cooled electric drive assembly oil leakage detection strategy according to an embodiment of the present invention. In Figure 3, considering that the motor can only perform oil leakage detection judgment after receiving feedback from the oil pump, the oil pump needs to perform phase current detection before feeding back the flag to the motor. In one embodiment of the present invention...

[0072] Step S30 involves setting the oil pump to reach a preset speed, then performing phase current detection and determining whether the second cumulative time of the oil pump operation is greater than or equal to a preset second time threshold. The first time threshold is greater than the second time threshold, ensuring that the phase current detection time of the oil pump is greater than the preset second time threshold before feedback results are generated. At the same time, the first time threshold is greater than the second time threshold to prevent the oil leakage detection from being shut down before the motor receives a feedback flag.

[0073] Step S31: If the second cumulative time of oil pump operation is greater than or equal to the preset second time threshold, the oil pump feedback ends.

[0074] Step S32 determines whether a cavitation failure has occurred based on the phase current result after the oil pump performs phase current detection.

[0075] In step S33, if a vacuum failure occurs, the oil pump will report a vacuum failure flag, and at the same time, the oil pump will stop phase current detection and reset the second cumulative time to zero.

[0076] In step S34, if no cavitation failure occurs, the oil pump stops phase current detection and resets the second cumulative time to zero.

[0077] Figure 4 shows a schematic block diagram of the oil leakage detection strategy for an oil-cooled electric drive assembly of an electric vehicle according to an embodiment of the present invention. Considering that the electric vehicle needs to maintain a certain vehicle condition during the process of receiving the feedback end flag, and the test of the termination condition is tested in real time, in one embodiment of the present invention, step S40 determines whether the current vehicle condition meets the termination condition, and at this time it also determines whether the end flag of the oil pump feedback has been received.

[0078] In step S41, if the termination conditions are met, the electric vehicle ends the oil leak detection operation and clears the first accumulated time.

[0079] In Figure 4, considering that when the motor receives the end flag from the oil pump feedback, it needs to report whether an oil leak has occurred based on the received suction fault flag, therefore, in one embodiment of the present invention,

[0080] Step S50 determines whether the current motor has received a suction fault flag from the oil pump;

[0081] In step S51, if the motor does not receive a suction fault indicator from the oil pump, the motor reports that the oil pump is not leaking oil.

[0082] Step S52: If the motor receives a suction failure flag from the oil pump, it is determined that the oil pump has experienced an oil leakage failure.

[0083] Figure 5-8 is a schematic block diagram illustrating the determination of the oil leak detection termination condition in an oil-cooled electric drive assembly oil leak detection strategy for an electric vehicle according to an embodiment of the present invention. In the figure, considering that changes in vehicle condition during the oil pump detection process may affect the oil leak detection, it is necessary to terminate the oil leak detection to ensure accuracy. Therefore, in one embodiment of the present invention, it is necessary to determine whether the termination condition is met based on the current vehicle condition. The termination condition includes:

[0084] Determine if a fault is reported when the oil pump performs an oil leak detection. If a fault is reported when the oil pump performs an oil leak detection, the current vehicle condition meets the conditions for termination.

[0085] Determine whether the electric vehicle's speed is less than the preset second minimum speed or greater than the preset second maximum speed. If the second minimum speed is less than the first minimum speed and the second maximum speed is greater than the first maximum speed, the current vehicle condition meets the termination condition.

[0086] Determine whether the oil temperature of the oil pump's cooling oil is lower than the preset second minimum temperature or higher than the second maximum temperature. If the second minimum temperature is lower than the first minimum temperature and the second maximum temperature is higher than the first maximum temperature, the current vehicle condition meets the termination condition.

[0087] Determine whether the absolute value of the electric vehicle's driving gradient is greater than the preset second gradient, and if the second gradient is greater than the first gradient, then the current vehicle condition meets the termination condition if the absolute value of the electric vehicle's driving gradient is greater than the preset second gradient.

[0088] If any of the following conditions are met in the current vehicle condition, such as vehicle speed, coolant temperature, oil pump, or the gradient of the electric vehicle, the oil leak detection will be stopped.

[0089] Considering the vehicle's operating conditions and the oil leak detection process, in one embodiment of the invention, the electric vehicle only acquires an oil leak detection result once per driving cycle, and the result is recorded. New oil leak detections can only be performed after the electric vehicle is restarted. This method helps ensure the accuracy of the detection while avoiding excessive use of the electric vehicle's equipment or systems.

[0090] A second aspect of the present invention provides an oil-cooled electric drive assembly for an electric vehicle. The oil-cooled electric drive assembly includes a motor controller, an oil-cooled motor, a reducer, and an oil pump. The oil-cooled motor is electrically connected to the motor controller, the reducer is drivenly connected to the oil-cooled motor, and the oil pump pipeline is connected to the oil-cooled motor and the reducer. The motor controller can be used to execute any of the detection strategies described above to realize oil leakage detection of the oil pump by the oil-cooled electric drive assembly.

[0091] Through the above technical solution, this detection strategy can diagnose the oil in the oil pump's oil chamber through the motor and oil pump without adding an oil level sensor. It can activate oil leakage detection according to preset conditions, and at the same time, the oil pump performs phase current detection. After detection, the oil pump can determine whether a cavitation fault has occurred based on the magnitude of the phase current. Compared with setting an oil level sensor or adding an anti-leakage pipeline, it can reduce costs and space occupation, and can detect and actively identify oil leakage in real time, thus ensuring the safety of electric vehicle operation.

[0092] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0093] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A leak detection strategy for an oil-cooled electric drive assembly in an electric vehicle, the electric vehicle comprising a motor and an oil pump, characterized in that, The detection strategy includes: Determine if the conditions for activating the oil leak detection are currently met; If the activation conditions are met, control the oil pump of the electric vehicle to a preset speed; Determine whether the end flag from the oil pump feedback has been received; If the end flag is not currently received, determine a first cumulative time during which the end flag has not been received; Determine whether the first cumulative time is greater than or equal to a preset first time threshold; If the first cumulative time is greater than or equal to a preset first time threshold, it is determined that there is no oil leakage.

2. The detection strategy according to claim 1, characterized in that, Determine whether the conditions for activating the oil leak detection are currently met, including: Determine whether the oil pump has reported any faults before it is started; If no fault is reported before the oil pump is turned on, determine whether the speed of the electric vehicle is between the preset first minimum speed and the first maximum speed, whether the temperature of the cooling oil of the oil pump is between the preset first minimum temperature and the first maximum temperature, and whether the absolute value of the driving gradient of the electric vehicle is less than the preset first gradient. When the vehicle speed of the electric vehicle is between a preset first minimum speed and a preset first maximum speed, the oil temperature of the cooling oil in the oil pump is between a preset first minimum temperature and a preset first maximum temperature, and the absolute value of the driving gradient of the electric vehicle is within a preset first gradient, it is determined that the current conditions for opening the oil leak detection are met.

3. The detection strategy according to claim 2, characterized in that, If the activation conditions are met, control the vehicle's oil pump to a preset speed, including: After the oil pump reaches a preset speed, phase current is detected and it is determined whether the second cumulative time of the oil pump operation is greater than or equal to a preset second time threshold, and the first time threshold is greater than the second time threshold. If the second cumulative time of the oil pump operation is greater than or equal to a preset second time threshold, the oil pump will output the end flag. Determine whether a vacuum failure has occurred based on the phase current; In the event of a vacuum failure, the oil pump will report a vacuum failure flag, stop the phase current detection, and reset the second cumulative time to zero. In the absence of a vacuum failure, the oil pump stops the phase current detection and resets the second cumulative time to zero.

4. The detection strategy according to claim 3, characterized in that, Determine whether an end flag has been received from the oil pump, including: Determine whether the current termination condition is met; If the aforementioned termination conditions are met, the oil leak detection operation is terminated, and the first accumulated time is cleared.

5. The detection strategy according to claim 4, characterized in that, Determine whether the oil pump feedback end flag has been received, including: Determine if an oil pump cavitation fault indicator has been received. If no cavitation fault indicator is received from the oil pump, it is determined that there is no oil leak; Upon receiving a feedback alarm from the oil pump indicating a vacuum fault, an oil leak is confirmed.

6. The detection strategy according to claim 4, characterized in that, Determining whether the current termination conditions are met includes: Determine whether the oil pump reports a fault during oil leak detection; If a fault is reported during the oil pump's leak detection, the termination condition is determined to be met. Determine whether the speed of the electric vehicle is less than a preset second minimum speed or greater than a preset second maximum speed, wherein the second minimum speed is less than the first minimum speed and the second maximum speed is greater than the first maximum speed; If the speed of the electric vehicle is less than the preset second minimum speed or greater than the second maximum speed, it is determined that the termination condition is met.

7. The detection strategy according to claim 4, characterized in that, Determine whether the current termination conditions are met, including: Determine whether the temperature of the cooling oil in the oil pump is less than a preset second minimum temperature or greater than a preset second maximum temperature, wherein the second minimum temperature is less than the first minimum temperature and the second maximum temperature is greater than the first maximum temperature. If the temperature of the cooling oil in the oil pump is less than the preset second minimum temperature or greater than the second maximum temperature, the termination condition is determined to be met.

8. The detection strategy according to claim 4, characterized in that, Determine whether the current termination conditions are met, including: Determine whether the absolute value of the driving gradient of the electric vehicle is greater than a preset second gradient, and whether the second gradient is greater than the first gradient; If the absolute value of the driving gradient of the electric vehicle is greater than the preset second gradient, it is determined that the termination condition is met.

9. The detection strategy according to claim 1, characterized in that, The electric vehicle acquires the oil leak detection information only once per driving cycle.

10. An oil-cooled electric drive assembly for an electric vehicle, characterized in that, The oil-cooled electric drive assembly includes: Motor controller; An oil-cooled motor, wherein the oil-cooled motor is electrically connected to the motor controller; The speed reducer is connected to the oil-cooled motor. An oil pump, the oil pump pipeline being connected to the oil-cooled motor and the reducer; The motor controller is used to execute the detection strategy as described in any one of claims 1 to 9.

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