Oil temperature control method and device of water-cooling electric drive system

Abstract

The invention discloses an oil temperature control method and device for a water-cooling electric drive system. The method comprises the steps that the rotating speed and torque of a vehicle motor at the current collection moment and historical accumulated heat in reducer oil at the previous collection moment are obtained; if the rotating speed is larger than a preset rotating speed threshold value, table look-up calculation is conducted in a preset target relation table according to the rotating speed and the torque, and the duration corresponding to the rotating speed is determined; according to the duration and the historical accumulated heat at the previous collection moment, target accumulated heat in the reducer oil at the current collection moment is determined; and if the target accumulated heat is greater than the heat threshold value, performing limit value updating on the torque according to the rotating speed and the target relation table to obtain the updated torque for motor adjustment and operation. Therefore, an accurate pre-judgment mechanism of the oil temperature risk is formed by collecting motor parameters in real time, looking up a table to judge the risk and calculating the accumulated heat; and when the heat exceeds the threshold value, the maximum torque output meeting the duration requirement is screened, and balance of safe temperature control and power retention is achieved.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to a method and apparatus for controlling oil temperature in a water-cooled electric drive system. Background Technology

[0002] In current automotive water-cooled electric drive systems, some reducer designs suffer from a critical lack of monitoring: the absence of an oil temperature sensor. This design flaw can lead to significant safety hazards under real-world conditions. For instance, when the reducer operates at high speed for extended periods, the internal gears and other components agitate the oil, causing the lubricating oil temperature to rise continuously. Due to the lack of a direct oil temperature detection device, the system cannot promptly detect overheating.

[0003] Excessive oil temperature can severely damage the reducer, especially accelerating the aging, deformation, and even failure of internal non-metallic components (such as seals and gaskets). Failure of non-metallic components not only compromises the reducer's sealing performance, leading to lubricant leakage, but also affects gear transmission accuracy, thus causing reducer malfunction. In severe cases, it can paralyze the entire water-cooled electric drive system, posing a significant threat to the vehicle's driving safety and reliability. Summary of the Invention

[0004] In view of the above problems, the present invention provides an oil temperature control method and device for a water-cooled electric drive system, realizing an accurate prediction mechanism for oil temperature risks; and when the heat exceeds the threshold, selecting the maximum torque output that meets the duration requirements, thereby achieving a balance between safe temperature control and power retention.

[0005] According to a first aspect of the present invention, a method for oil temperature control in a water-cooled electric drive system is provided, comprising:

[0006] Obtain the vehicle motor speed and torque at the current data collection time, as well as the historical cumulative heat in the reducer oil at the previous data collection time;

[0007] If the rotational speed is greater than a preset rotational speed threshold, then based on the rotational speed and the torque, the duration corresponding to the rotational speed is determined by looking up the table in the preset target relationship table; wherein, the target relationship table includes the target rotational speed and multiple sets of target test data corresponding to the target rotational speed, the target test data includes the target power, the target torque and the target duration, the target duration refers to the duration during which the reducer oil temperature is lower than the target temperature when the motor is running at the target rotational speed;

[0008] Based on the duration and the historical accumulated heat at the previous sampling time, the target accumulated heat in the reducer oil at the current sampling time is determined.

[0009] If the target accumulated heat is greater than the heat threshold, the torque is updated according to the rotational speed and the target relationship table to obtain the updated torque, which is used to adjust the operation of the motor.

[0010] Optionally, constructing the target relation table includes:

[0011] The drain plug in the reducer of the test vehicle was modified.

[0012] An oil temperature sensor is placed in the oil tank of the reducer to collect the oil temperature of the reducer in the oil tank;

[0013] Operating condition tests were conducted on a test bench to obtain a target relationship table regarding the target speed, target torque, target power, and target duration.

[0014] Optionally, after acquiring the vehicle motor's speed and torque at the current acquisition time, and the historical accumulated heat generated in the reducer at the previous acquisition time, the method further includes:

[0015] If the rotation speed is less than or equal to a preset rotation speed threshold, then the historical accumulated heat at the previous acquisition time will be used as the target accumulated heat at the current acquisition time.

[0016] Optionally, determining the target cumulative heat in the reducer oil at the current sampling time based on the duration and the historical cumulative heat at the previous sampling time includes:

[0017] Based on the duration, the change in heat between the current sampling time and the previous sampling time is determined;

[0018] Based on the change in heat and the historical cumulative heat at the previous sampling time, the target cumulative heat in the reducer oil at the current sampling time is determined.

[0019] Optionally, updating the torque based on the rotational speed and the target relationship table to obtain the updated torque includes:

[0020] Based on the rotational speed, match the target relationship table to obtain multiple sets of corresponding target test data;

[0021] The corresponding multiple sets of target test data are filtered and processed, and the target test data with a target duration greater than the duration threshold are retained;

[0022] From the screened target test data, the target torque with the largest value is taken as the updated torque.

[0023] Optionally, the method further includes:

[0024] If the collected rotational speeds are all less than the rotational speed threshold within a preset time period after the motor has been adjusted and operated, the motor will stop adjusting and operating.

[0025] Optionally, before obtaining the vehicle motor speed and torque at the current sampling time and the historical accumulated heat in the reducer oil at the previous sampling time, the method further includes:

[0026] Set the historical cumulative heat corresponding to the initial data collection time to 0.

[0027] According to a second aspect of the present invention, an oil temperature control device for a water-cooled electric drive system is provided, comprising:

[0028] The acquisition module is used to acquire the vehicle motor speed and torque at the current acquisition time, as well as the historical cumulative heat in the reducer oil at the previous acquisition time.

[0029] The lookup table module is used to determine the duration corresponding to the rotational speed by looking up a table in a preset target relationship table based on the rotational speed and the torque if the rotational speed is greater than a preset rotational speed threshold. The target relationship table includes a target rotational speed and multiple sets of target test data corresponding to the target rotational speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature is lower than the target temperature at the target rotational speed.

[0030] The determination module is used to determine the target cumulative heat in the reducer oil at the current acquisition time based on the duration and the historical cumulative heat at the previous acquisition time.

[0031] The adjustment module is used to update the torque limit according to the rotational speed and the target relationship table if the target accumulated heat is greater than the heat threshold, so as to obtain the updated torque for adjusting the operation of the motor.

[0032] According to a third aspect of the present invention, a controller is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the aforementioned oil temperature control method for a water-cooled electric drive system.

[0033] According to a fourth aspect of the present invention, a vehicle is provided, the vehicle including a vehicle body and a controller installed in the vehicle body, wherein the controller executes the aforementioned oil temperature control method for a water-cooled electric drive system.

[0034] The above-described one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0035] This specification provides an oil temperature control method and apparatus for a water-cooled electric drive system. It acquires the vehicle motor's speed and torque at the current acquisition time, as well as the historical accumulated heat in the reducer oil at the previous acquisition time. If the speed is greater than a preset speed threshold, it calculates the duration corresponding to the speed by looking up the speed and torque in a preset target relationship table. The target relationship table includes a target speed and multiple sets of target test data corresponding to the target speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature remains below the target temperature when the motor is running at the target speed. Based on the duration and the historical accumulated heat at the previous acquisition time, it determines the target accumulated heat in the reducer oil at the current acquisition time. If the target accumulated heat is greater than a heat threshold, it updates the torque limit based on the speed and the target relationship table to obtain an updated torque for adjusting the motor's operation. In this way, by collecting motor parameters in real time, looking up tables to assess risks, and calculating accumulated heat, a precise prediction mechanism for oil temperature risks is formed. When the heat exceeds the threshold, the maximum torque output that meets the duration requirements is selected, achieving a balance between safe temperature control and power preservation. Overall, this effectively avoids the failure of non-metallic components in the reducer due to high temperatures, ensures the stable operation of the electric drive system, and significantly improves the safety, reliability, and power practicality of the entire vehicle.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0037] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0038] Figure 1 A flowchart of an oil temperature control method for a water-cooled electric drive system according to an embodiment of the present invention is shown.

[0039] Figure 2 A block diagram of an oil temperature control device for a water-cooled electric drive system according to an embodiment of the present invention is shown. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] This invention provides a method for oil temperature control in a water-cooled electric drive system, combined with... Figure 1 The flowchart shown illustrates that the oil temperature control method for this water-cooled electric drive system includes steps 101 to 104:

[0045] Step 101: Obtain the vehicle motor speed and torque at the current data collection time, as well as the historical cumulative heat in the reducer oil at the previous data collection time;

[0046] In this embodiment, the vehicle motor's operating parameters at the current acquisition time are obtained by relying on the CAN bus data transmission network of the vehicle's electric drive system. The motor speed data can be obtained from the speed sensor built into the motor controller, which can capture the motor rotor rotation frequency in real time and convert it into a standard speed signal (unit: r / min). The motor torque data can be calculated and generated by the motor controller based on the current and voltage signals and motor characteristic curves under the current operating conditions, ensuring that the data can reflect the actual output torque of the motor (unit: N·m).

[0047] At the same time, the historical accumulated heat of the reducer oil (or the lubricating oil in the reducer) at the previous acquisition time will be retrieved synchronously. This historical data was generated within the previous acquisition cycle. It should be noted that if the current acquisition time is the first data acquisition time (i.e., the initial acquisition time), then the historical accumulated heat of the reducer oil at the previous acquisition time involved in this step will be set to 0.

[0048] Step 102: If the rotational speed is greater than a preset rotational speed threshold, then based on the rotational speed and the torque, the duration corresponding to the rotational speed is determined by looking up the table in the preset target relationship table; wherein, the target relationship table includes the target rotational speed and multiple sets of target test data corresponding to the target rotational speed, the target test data includes the target power, the target torque and the target duration, and the target duration refers to the duration during which the reducer oil temperature is lower than the target temperature when the motor is running at the target rotational speed;

[0049] In this embodiment, the actual motor speed obtained at the current acquisition time is compared with a preset speed threshold. This speed threshold is a key critical value set based on previous bench test data, which usually corresponds to the node where the vehicle switches from low-speed operation to medium-high-speed operation.

[0050] When the speed is below the threshold, the reducer's oil stirring intensity is low and the oil temperature rises slowly, so there is no need to start searching for the duration. At this time, the historical accumulated heat at the previous collection time can be used as the target accumulated heat at the current collection time for updating.

[0051] The table lookup calculation is only initiated when the rotational speed exceeds the threshold, thus avoiding unnecessary computational overhead.

[0052] Subsequently, using the current motor speed and torque as the core search criteria, a matching calculation is performed in a pre-set target relationship table to determine the duration at the corresponding speed. The target relationship table is a structured data table constructed through prior bench testing. The table uses "target speed" as the core classification dimension, and each target speed is associated with multiple sets of target test data: each set of data includes target power (corresponding to different load conditions), target torque (with a conversion relationship to power), and target duration. This target duration specifically refers to the maximum duration for which the motor can operate stably at the target speed, corresponding target power / target torque, and the reducer oil temperature remains below the pre-set target temperature (e.g., the upper limit of the safe temperature to prevent non-metallic component failure), ensuring that the duration obtained from the table directly reflects the safe operating boundary of the oil temperature under the current operating conditions.

[0053] In an optional embodiment, the step of constructing the target relation table may include:

[0054] The drain plug in the reducer of the test vehicle was modified to connect to the oil temperature sensor.

[0055] An oil temperature sensor is placed in the oil tank of the reducer to collect the oil temperature of the reducer in the oil tank;

[0056] Operating condition tests were conducted on a test bench to obtain a target relationship table regarding the target speed, target torque, target power, and target duration.

[0057] The test vehicle refers to a modified vehicle with the same model as the aforementioned vehicle. In this embodiment, the vehicle does not have an oil temperature sensor in its transmission.

[0058] The drain bolt of the test vehicle's reducer was modified accordingly: After disassembling the original drain bolt, a suitable mounting channel and sealing groove were machined inside the bolt according to the interface specifications of the oil temperature sensor (such as thread size and signal transmission interface type). At the same time, a sensor cable lead-out hole was reserved on the outer wall of the bolt. After the modification was completed, the detection end of the oil temperature sensor was inserted into the reducer through the bolt channel to ensure that the sensor could directly contact the oil. Then, the installation gap was sealed with a sealant to prevent oil leakage and achieve a stable connection between the drain bolt and the oil temperature sensor.

[0059] Secondly, additional oil temperature sensors are installed inside the reducer oil tank: based on the characteristics of the oil flow path and temperature distribution inside the oil tank, select locations with active oil circulation and strong temperature representativeness (such as the side wall of the oil tank near the gear meshing area, or the oil accumulation area at the bottom of the oil tank), and install additional oil temperature sensors by welding or thread fixing. This forms a "dual-point monitoring" system with the sensor on the modified drain bolt, avoiding data loss due to the failure of a single sensor and ensuring accurate and real-time collection of reducer oil temperature data in different areas of the oil tank.

[0060] Finally, systematic operating condition tests were conducted on a test bench to construct a target relationship table: First, the electric drive system (including reducer and motor) of the test vehicle was fixed on the test bench, and the power simulation device, data acquisition system, and oil temperature monitoring system were connected; then, the test operating condition parameters were set, in which the motor speed covered the vehicle's high-speed cruising speed (e.g., 1500 r / min) to the speed corresponding to the maximum vehicle speed (e.g., 6000 r / min), and multiple target speed levels could be divided in 500 r / min increments; the motor power gradually decreased from the rated power (e.g., 120 kW) downwards (e.g., in increments of 10 kW), corresponding to different target torques (calculated by power = speed × torque ÷ constant); under each combination of target speed and target power, the test bench was started and the oil temperature changes were recorded. When the oil temperature reached the preset target temperature (e.g., 120 degrees Celsius, i.e., the upper limit of the safe temperature for non-metallic parts), the timing was stopped, and this duration was the target duration under that operating condition; the target speed, target torque, target power, and corresponding target duration of all test groups were compiled and summarized to form a structured target relationship table.

[0061] Step 103: Determine the target cumulative heat in the reducer oil at the current sampling time based on the duration and the historical cumulative heat at the previous sampling time;

[0062] The duration obtained from the table in the aforementioned steps is essentially the critical time for the reducer oil temperature to reach its safe upper limit under the current speed and torque conditions. The steps for calculating the target accumulated heat may include:

[0063] Based on the duration, the change in heat between the current sampling time and the previous sampling time is determined;

[0064] Based on the change in heat and the historical cumulative heat at the previous sampling time, the target cumulative heat in the reducer oil at the current sampling time is determined.

[0065] Specifically, the target cumulative heat can be calculated using the following formula:

[0066]

[0067] Among them, C t C represents the target accumulated heat in the reducer oil at the previous data acquisition time. t-1 This represents the historical accumulated heat at the previous data collection time. The change in heat is represented by d, and the duration is d.

[0068] Additionally, if the rotational speed cannot be directly matched to the target rotational speed in the target relationship table, interpolation can be used to calculate the duration. The interpolation calculation steps may include:

[0069] Traverse the target relationship table to find the maximum rotational speed n that is less than the rotational speed n. s Then find the maximum torque T that is less than the torque T. s1 The minimum torque T greater than T s2 The first duration is d. s :

[0070]

[0071] Traverse the target relation table to find the minimum rotational speed n greater than n. b Then find the maximum torque T that is less than T. b1 The minimum torque T greater than T b2 The second duration is d. b :

[0072]

[0073] Calculate the duration d corresponding to the rotational speed n and torque T:

[0074]

[0075] Step 104: If the target accumulated heat is greater than the heat threshold, then according to the rotational speed and the target relationship table, the torque is updated to obtain the updated torque, which is used to adjust the operation of the motor.

[0076] After calculating the target cumulative heat, a comparison is made between the target cumulative heat and the heat threshold. If the current target cumulative heat is greater than the heat threshold, it means that the reducer oil is close to or has reached the upper limit of the safe temperature. The torque limit needs to be updated to reduce heat generation and avoid failure of non-metallic parts.

[0077] In an optional embodiment, the step of updating the limit value of the torque may include:

[0078] Based on the rotational speed, match the target relationship table to obtain multiple sets of corresponding target test data;

[0079] The corresponding multiple sets of target test data are filtered and processed, and the target test data with a target duration greater than the duration threshold are retained;

[0080] From the screened target test data, the target torque with the largest value is taken as the updated torque.

[0081] Specifically, the process begins by using the current engine speed as the core search condition. It precisely matches the same or closest "target speed" entry in the target relationship table (e.g., if the current speed is 3200 r / min, match target speeds of 3000 r / min or 3500 r / min in the table, prioritizing entries with an error of less than 5%). This yields all sets of target test data corresponding to that target speed (each set includes target power, target torque, and target duration). Next, this data is filtered, and a duration threshold is set (e.g., 30 minutes, which can be adjusted according to the vehicle model and usage scenario). Data with a target duration longer than this threshold are retained. This filtering ensures that the selected torque can support stable long-term motor operation, avoiding frequent adjustments. Finally, the target torque with the largest value is extracted from the filtered test data as the updated torque limit. This limit satisfies the heat dissipation balance requirements at the current speed while maximizing the preservation of motor power performance, avoiding excessive torque limitation that could negatively impact the driving experience.

[0082] After receiving the updated torque limit, the motor controller will adjust the output current and voltage in real time to control the actual output torque of the motor within the limit (i.e., the updated torque). By reducing power loss, the heat generation of the reducer oil is reduced, and the oil temperature is gradually controlled within a safe range, thus achieving risk warning and dynamic regulation.

[0083] In addition, if the collected rotational speeds are all less than the rotational speed threshold within a preset time period after the motor has been adjusted (e.g., 30 minutes), the motor will end the current adjustment operation and exit the current torque limitation.

[0084] In summary, the oil temperature control method for a water-cooled electric drive system provided in this specification involves acquiring the vehicle motor's speed and torque at the current acquisition time, as well as the historical accumulated heat in the reducer oil at the previous acquisition time. If the speed is greater than a preset speed threshold, the method calculates the duration corresponding to the speed by looking up the speed and torque in a preset target relationship table. The target relationship table includes a target speed and multiple sets of target test data corresponding to the target speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature remains below the target temperature when the motor is running at the target speed. The method determines the target accumulated heat in the reducer oil at the current acquisition time based on the duration and the historical accumulated heat at the previous acquisition time. If the target accumulated heat is greater than a heat threshold, the torque is updated according to the speed and the target relationship table to obtain an updated torque for adjusting the motor's operation. In this way, by collecting motor parameters in real time, looking up tables to assess risks, and calculating accumulated heat, a precise prediction mechanism for oil temperature risks is formed. When the heat exceeds the threshold, the maximum torque output that meets the duration requirements is selected, achieving a balance between safe temperature control and power preservation. Overall, this effectively avoids the failure of non-metallic components in the reducer due to high temperatures, ensures the stable operation of the electric drive system, and significantly improves the safety, reliability, and power practicality of the entire vehicle.

[0085] Based on the same inventive concept, combined with Figure 2 As shown, this embodiment of the invention also provides an oil temperature control device for a water-cooled electric drive system, comprising:

[0086] The acquisition module is used to acquire the vehicle motor speed and torque at the current acquisition time, as well as the historical cumulative heat in the reducer oil at the previous acquisition time.

[0087] The lookup table module is used to determine the duration corresponding to the rotational speed by looking up a table in a preset target relationship table based on the rotational speed and the torque if the rotational speed is greater than a preset rotational speed threshold. The target relationship table includes a target rotational speed and multiple sets of target test data corresponding to the target rotational speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature is lower than the target temperature at the target rotational speed.

[0088] The determination module is used to determine the target cumulative heat in the reducer oil at the current acquisition time based on the duration and the historical cumulative heat at the previous acquisition time.

[0089] The adjustment module is used to update the torque limit according to the rotational speed and the target relationship table if the target accumulated heat is greater than the heat threshold, so as to obtain the updated torque for adjusting the operation of the motor.

[0090] Optionally, the table lookup module is also used for:

[0091] The drain plug in the reducer of the test vehicle was modified.

[0092] An oil temperature sensor is placed in the oil tank of the reducer to collect the oil temperature of the reducer in the oil tank;

[0093] Operating condition tests were conducted on a test bench to obtain a target relationship table regarding the target speed, target torque, target power, and target duration.

[0094] Optionally, the acquisition module is also used for:

[0095] If the rotation speed is less than or equal to a preset rotation speed threshold, then the historical accumulated heat at the previous acquisition time will be used as the target accumulated heat at the current acquisition time.

[0096] Optionally, the determination module is also used for:

[0097] Based on the duration, the change in heat between the current sampling time and the previous sampling time is determined;

[0098] Based on the change in heat and the historical cumulative heat at the previous sampling time, the target cumulative heat in the reducer oil at the current sampling time is determined.

[0099] Optionally, the adjustment module is also used for:

[0100] Based on the rotational speed, match the target relationship table to obtain multiple sets of corresponding target test data;

[0101] The corresponding multiple sets of target test data are filtered and processed, and the target test data with a target duration greater than the duration threshold are retained;

[0102] From the screened target test data, the target torque with the largest value is taken as the updated torque.

[0103] Optionally, the adjustment module is also used for:

[0104] If the collected rotational speeds are all less than the rotational speed threshold within a preset time period after the motor has been adjusted and operated, the motor will stop adjusting and operating.

[0105] Optionally, the acquisition module is also used for:

[0106] Set the historical cumulative heat corresponding to the initial data collection time to 0.

[0107] In summary, the oil temperature control device for a water-cooled electric drive system provided in this specification acquires the vehicle motor's speed and torque at the current acquisition time, as well as the historical accumulated heat in the reducer oil at the previous acquisition time. If the speed is greater than a preset speed threshold, the device calculates the duration corresponding to the speed by looking up the speed and torque in a preset target relationship table. The target relationship table includes a target speed and multiple sets of target test data corresponding to the target speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature remains below the target temperature when the motor is running at the target speed. The device determines the target accumulated heat in the reducer oil at the current acquisition time based on the duration and the historical accumulated heat at the previous acquisition time. If the target accumulated heat is greater than a heat threshold, the torque is updated according to the speed and the target relationship table to obtain an updated torque for adjusting the motor's operation. In this way, by collecting motor parameters in real time, looking up tables to assess risks, and calculating accumulated heat, a precise prediction mechanism for oil temperature risks is formed. When the heat exceeds the threshold, the maximum torque output that meets the duration requirements is selected, achieving a balance between safe temperature control and power preservation. Overall, this effectively avoids the failure of non-metallic components in the reducer due to high temperatures, ensures the stable operation of the electric drive system, and significantly improves the safety, reliability, and power practicality of the entire vehicle.

[0108] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the oil temperature control device of the water-cooled electric drive system described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0109] According to a third aspect of the present invention, a controller is provided, the controller including an oil temperature control device for a water-cooled electric drive system, a memory, a processor and a communication unit, the memory storing machine-readable instructions executable by the processor, and when the controller is running, the processor and the memory communicate via a bus, the processor executes the machine-readable instructions and executes the oil temperature control method for the water-cooled electric drive system.

[0110] The memory, processor, and communication unit are electrically connected directly or indirectly to achieve signal transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The oil temperature control device of the water-cooled electric drive system includes at least one software function module that can be stored in the memory in the form of software or firmware. The processor is used to execute the executable module stored in the memory (e.g., the software function module or computer program included in the oil temperature control device of the water-cooled electric drive system).

[0111] The memory can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc.

[0112] In some embodiments, the processor is used to perform one or more functions described in this embodiment. In some embodiments, the processor may include one or more processing cores (e.g., a single-core processor (S) or a multi-core processor (S)).

[0113] In this embodiment, the memory is used to store the program, and the processor is used to execute the program after receiving the execution instruction. The process definition method disclosed in any implementation of this embodiment can be applied to the processor, or implemented by the processor.

[0114] The communication unit is used to establish communication connections between the controller and other devices via the network, and to send and receive data via the network.

[0115] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the controller described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0116] According to a fourth aspect of the present invention, a vehicle is provided, including a vehicle body and a controller installed in the vehicle body, the controller being used to implement the aforementioned oil temperature control method for a water-cooled electric drive system.

[0117] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the vehicle controller described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0118] The above are merely various embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for controlling oil temperature in a water-cooled electric drive system, characterized in that, include: Obtain the vehicle motor speed and torque at the current data collection time, as well as the historical cumulative heat in the reducer oil at the previous data collection time; If the rotational speed is greater than a preset rotational speed threshold, then based on the rotational speed and the torque, the duration corresponding to the rotational speed is determined by looking up the table in the preset target relationship table; wherein, the target relationship table includes the target rotational speed and multiple sets of target test data corresponding to the target rotational speed, the target test data includes the target power, the target torque and the target duration, the target duration refers to the duration during which the reducer oil temperature is lower than the target temperature when the motor is running at the target rotational speed; Based on the duration and the historical accumulated heat at the previous sampling time, the target accumulated heat in the reducer oil at the current sampling time is determined. If the target accumulated heat is greater than the heat threshold, the torque is updated according to the rotational speed and the target relationship table to obtain the updated torque, which is used to adjust the operation of the motor.

2. The method according to claim 1, characterized in that, Constructing the target relation table includes: The drain plug in the reducer of the test vehicle was modified. An oil temperature sensor is placed in the oil tank of the reducer to collect the oil temperature of the reducer in the oil tank; Operating condition tests were conducted on a test bench to obtain a target relationship table regarding the target speed, target torque, target power, and target duration.

3. The method according to claim 1, characterized in that, After acquiring the vehicle motor's speed and torque at the current acquisition time, and the historical accumulated heat generated in the reducer at the previous acquisition time, the method further includes: If the rotation speed is less than or equal to a preset rotation speed threshold, then the historical accumulated heat at the previous acquisition time will be used as the target accumulated heat at the current acquisition time.

4. The method according to claim 1, characterized in that, Determining the target cumulative heat in the reducer oil at the current sampling time based on the duration and the historical cumulative heat at the previous sampling time includes: Based on the duration, the change in heat between the current sampling time and the previous sampling time is determined; Based on the change in heat and the historical cumulative heat at the previous sampling time, the target cumulative heat in the reducer oil at the current sampling time is determined.

5. The method according to claim 1, characterized in that, The step of updating the torque limit based on the rotational speed and the target relationship table to obtain the updated torque includes: Based on the rotational speed, match the target relationship table to obtain multiple sets of corresponding target test data; The corresponding multiple sets of target test data are filtered and processed, and the target test data with a target duration greater than the duration threshold are retained; From the screened target test data, the target torque with the largest value is taken as the updated torque.

6. The method according to claim 1, characterized in that, The method further includes: If the collected rotational speeds are all less than the rotational speed threshold within a preset time period after the motor has been adjusted and operated, the motor will stop adjusting and operating.

7. The method according to claim 1, characterized in that, Before acquiring the vehicle motor speed and torque at the current acquisition time, and the historical cumulative heat in the reducer oil at the previous acquisition time, the method further includes: Set the historical cumulative heat corresponding to the initial data collection time to 0.

8. An oil temperature control device for a water-cooled electric drive system, characterized in that, include: The acquisition module is used to acquire the vehicle motor speed and torque at the current acquisition time, as well as the historical cumulative heat in the reducer oil at the previous acquisition time. The lookup table module is used to determine the duration corresponding to the rotational speed by looking up a table in a preset target relationship table based on the rotational speed and the torque if the rotational speed is greater than a preset rotational speed threshold. The target relationship table includes a target rotational speed and multiple sets of target test data corresponding to the target rotational speed. The target test data includes target power, target torque, and target duration. The target duration refers to the duration during which the reducer oil temperature is lower than the target temperature at the target rotational speed. The determination module is used to determine the target cumulative heat in the reducer oil at the current acquisition time based on the duration and the historical cumulative heat at the previous acquisition time. The adjustment module is used to update the torque limit according to the rotational speed and the target relationship table if the target accumulated heat is greater than the heat threshold, so as to obtain the updated torque for adjusting the operation of the motor.

9. A controller, characterized in that, The controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the oil temperature control method of the water-cooled electric drive system according to any one of claims 1-7.

10. A vehicle, characterized in that, The vehicle includes a vehicle body and a controller installed in the vehicle body, wherein the controller executes the oil temperature control method of the water-cooled electric drive system according to any one of claims 1-7.

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