Overheat Protection Method for K0 Clutch and Hybrid Electric Vehicle

Abstract

The present invention provides an overheat protection method for a K0 clutch and a hybrid vehicle. The overheat protection method for the K0 clutch of the present invention monitors the working state and operating temperature of the K0 clutch in real time, sets multiple levels of temperature protection thresholds for the K0 clutch, and multiple levels of overheat protection measures for suppressing the temperature rise of the K0 clutch corresponding to each temperature protection threshold; when the K0 clutch is in the working state and the operating temperature exceeds a certain level of temperature protection threshold, the corresponding level of overheat protection measure is taken. In the process of overheating of the K0 clutch in the overheat protection method for the K0 clutch of the present invention, each time a level of temperature protection threshold is breached, corresponding overheat protection measures will gradually strengthen the suppression of the temperature rise of the K0 clutch, which can effectively slow down the process of overheating of the K0 clutch to reduce the risk of serious overheating of the K0 clutch.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and particularly to an overheat protection method for a K0 clutch. In addition, the present invention also relates to a hybrid vehicle. Background Art

[0002] The K0 clutch is a set of independent clutches used to couple or decouple the engine. It is arranged inside the motor rotor. The spline of the inner hub of the clutch is connected to the dual-mass flywheel of the engine, and the outer hub of the clutch is located on the motor rotor.

[0003] In current hybrid vehicles, as a set of independent clutches, one end of the K0 clutch is connected to the engine and the other end is connected to the P2 motor. By engaging and disengaging the K0 clutch, the vehicle driving mode can be switched between different modes such as EV, series, and parallel, and functions such as starting and stopping control of the engine can be coordinated.

[0004] Since the K0 clutch is located between the engine and the motor, based on the needs of driving mode switching and engine start-stop control and other working conditions, the K0 clutch will frequently switch between states such as slip friction, engagement, and disengagement. Its working environment is more severe than that of other clutches in the transmission. To prevent the clutch from being damaged due to overheating, the TCU (Transmission Control Unit) continuously monitors and diagnoses whether the K0 clutch has an overheat fault.

[0005] When a hybrid vehicle detects that the overheat fault of the K0 clutch is triggered, the fault response method is usually to directly open the K0 clutch and not allow the K0 to continue working. After the temperature sensor of the K0 clutch or the temperature sensor at the oil pan (for vehicles without a temperature sensor for the K0 clutch, the temperature of the K0 clutch is generally estimated by the oil temperature) fails, the fault response is usually to use a fixed value to replace the real oil temperature or open the K0 clutch. The above control and protection strategies for the K0 clutch have three problems:

[0006] (1) When the oil temperature sensor fails, the use of the fixed value replacement strategy lacks further necessary protection, and there is a potential risk of damage to the K0 clutch; directly opening the K0 clutch reduces the usability of the vehicle driving mode;

[0007] (2) Monitoring the overheat of the K0 clutch usually triggers an overheat fault after the clutch reaches the highest temperature threshold it can withstand. At this moment, the clutch has often been ablated, and there is no pre-treatment monitoring and protection before overheating, resulting in lagging protection, poor diagnostic accuracy and effectiveness;

[0008] (3) The K0 clutch stops working when it is overheated and continues to work after the temperature drops. There is a problem of repeated overheating causing the K0 clutch to frequently open and close, resulting in poor vehicle drivability. When the number of overheating times in the same driving cycle is large, it is very easy to cause the K0 clutch to burn out. Summary of the invention

[0009] In view of this, the present invention aims to propose a K0 clutch overheating protection method, so as to provide a K0 clutch overheating protection technical solution which is beneficial to reducing the risk of K0 clutch overheating.

[0010] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0011] A method for overheating protection of a K0 clutch is disclosed. The method monitors the working state and operating temperature of the K0 clutch in real time, and sets multiple levels of temperature protection thresholds for the K0 clutch, and multiple levels of overheating protection measures corresponding to each of the temperature protection thresholds for suppressing the temperature increase of the K0 clutch; when the K0 clutch is in the working state and the operating temperature exceeds a certain level of the temperature protection threshold, the corresponding level of the overheating protection measures is adopted.

[0012] Furthermore, the operating temperature is obtained by a temperature sensor, and the temperature sensor includes a clutch temperature sensor and / or an oil pan temperature sensor.

[0013] Furthermore, when the temperature sensor fails abnormally, the engine is prohibited from shutting down, and the load torque of the K0 clutch is reduced.

[0014] Furthermore, a temperature compensation value Δt is set for the temperature protection threshold of each level; after the overheating protection measures of the corresponding level are taken, the overheating protection measures of this level are lifted only when the operating temperature drops below the difference between the temperature protection threshold of the corresponding level and the temperature compensation value Δt.

[0015] Furthermore, the multiple levels of temperature protection thresholds include a first-level temperature threshold T1, a second-level temperature threshold T2 and a third-level temperature threshold T3 which increase in sequence; the multiple levels of overheating protection measures include a first-level overheating protection measure set corresponding to the first-level temperature threshold T1, a second-level overheating protection measure set corresponding to the second-level temperature threshold T2, and a third-level overheating protection measure set corresponding to the third-level temperature threshold T3.

[0016] Furthermore, the first-level overheat protection measure includes: prohibiting engine shutdown.

[0017] Further, the secondary overheat protection measure includes: reducing the load torque of the K0 clutch and increasing the engagement force of the K0 clutch.

[0018] Further, the tertiary overheat protection measure includes: disengaging the K0 clutch and prohibiting the engine from starting.

[0019] Further, count the number of times the operating condition temperature exceeds the tertiary temperature threshold T3 and accumulate it as the overheat count N, and set a count threshold Nc; when the overheat count N is greater than the count threshold Nc, maintain the tertiary overheat protection measure until the vehicle is powered off, and clear the overheat count N after the vehicle is powered off.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The overheat protection method of the K0 clutch of the present invention, by setting multiple levels of temperature protection thresholds and corresponding multi-level overheat protection measures, during the overheating process of the K0 clutch, each time a level of temperature protection threshold is breached, there will be corresponding overheat protection measures to gradually strengthen the suppression of the temperature rise of the K0 clutch, which can effectively slow down the overheating process of the K0 clutch to reduce the risk of serious overheating of the K0 clutch, thereby providing a technical solution for the overheat protection of the K0 clutch that is conducive to reducing the overheat risk of the K0 clutch.

[0022] In addition, by setting a temperature sensor, the operating condition temperature of the K0 clutch can be detected in a timely and reliable manner, which is conducive to accurately judging the situation where the K0 clutch exceeds each level of temperature protection threshold. The temperature sensor uses a clutch temperature sensor or an oil pan temperature sensor, which is convenient for installation and configuration and is conducive to improving the accuracy of the detected operating condition temperature. When the temperature sensor fails abnormally and the operating condition temperature of the K0 clutch cannot be obtained in real time, measures such as prohibiting the engine from stopping, requesting to reduce the input torque of the transmission to reduce the load torque of the K0 clutch, and supplementing with requests for the K0 clutch to engage urgently can be taken; avoiding the K0 clutch from being directly disengaged, and when the high-voltage battery power is insufficient, the endurance performance of the vehicle can be effectively improved. Moreover, compared with the strategy of using a fixed value to replace the real operating condition temperature, necessary comprehensive protection measures are added, reducing the risk of overheat ablation damage of the K0 clutch.

[0023] Another object of the present invention is to propose a hybrid vehicle, and the K0 clutch of the hybrid vehicle adopts the overheat protection method of the K0 clutch of the present invention. The hybrid vehicle of the present invention has the technical advantages possessed by the above-mentioned overheat protection method of the K0 clutch. Description of the Drawings

[0024] The accompanying drawings that form a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention. The front-back, up-down and other orientation terms involved herein are only used to represent relative positional relationships and do not constitute any undue limitation to the present invention. In the accompanying drawings:

[0025] Figure 1 It is a schematic diagram of the control flow of the overheat protection method for the K0 clutch according to the first embodiment of the present invention;

[0026] Figure 2 It is a schematic diagram of the composition of the control system of the K0 clutch of the hybrid vehicle according to the first embodiment of the present invention.

[0027] Explanation of reference numerals:

[0028] 1. K0 clutch; 2. Control unit; 20. Calculator; 21. Memory; 22. Counter; 3. Temperature sensor; 31. Clutch temperature sensor; 32. Oil pan temperature sensor. Detailed implementation manners

[0029] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0030] In the description of the present invention, it should be noted that the TCU (Transmission Control Unit) refers to the automatic transmission control unit, which controls the transmission to switch different gears to realize the vehicle driving and parking functions; compared with the manual transmission, the automatic transmission adds a controller, a shift actuator and sensors, and can automatically select the best shift working condition according to the vehicle speed and the engine and motor speeds to perform automatic shift operation.

[0031] The HCU (Hybrid Control Unit) refers to the hybrid vehicle controller, which is responsible for functions such as the energy distribution and torque management of the entire power system. The ECM (Engine Control Module) refers to the engine control unit, which is responsible for controlling the normal operation of the engine. In the following description, the control unit mentioned may be the TCU or the HCU, or a combination of both; the HCU herein may also be an ECM or other control devices that can control the engine start-stop and the transmission.

[0032] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection", and "connector" should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific situations.

[0033] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0034] Embodiment 1

[0035] This embodiment relates to an overheat protection method for a K0 clutch, and provides a technical solution for the overheat protection of the K0 clutch 1 that is conducive to reducing the overheat risk of the K0 clutch 1; an exemplary control flow thereof is as Figure 1 shown, and an exemplary composition of the control system involved in this overheat protection method is as Figure 2 shown.

[0036] Overall, this overheat protection method for the K0 clutch monitors the working state and operating temperature of the K0 clutch 1 in real time, and sets multiple levels of temperature protection thresholds for the K0 clutch 1, as well as multiple levels of overheat protection measures for suppressing the temperature rise of the K0 clutch 1 corresponding to each temperature protection threshold; when the K0 clutch 1 is in a working state and the operating temperature exceeds a certain level of temperature protection threshold, the corresponding level of overheat protection measures is taken.

[0037] During the process of real-time monitoring of the working state and operating temperature of the K0 clutch 1, the operating temperature is preferably obtained through a temperature sensor 3, and the temperature sensor 3 includes a clutch temperature sensor 31 and / or an oil pan temperature sensor 32. By setting the temperature sensor 3, the operating temperature of the K0 clutch 1 can be detected in a timely and reliable manner, which is conducive to accurately judging the situation where the K0 clutch 1 exceeds each level of temperature protection threshold. The temperature sensor 3 uses a clutch temperature sensor 31 or an oil pan temperature sensor 32, which is convenient for installation and configuration and is conducive to improving the accuracy of the detected operating temperature. Of course, for the monitoring of the working state, in addition to monitoring different working state conditions such as the opening and disengaging or engaging and pressing of the K0 clutch 1, the pressing pressure of the K0 clutch 1, the engine speed, the vehicle speed, and the cooling oil flow of the transmission can also be monitored to comprehensively control the running conditions of the vehicle.

[0038] In this embodiment, when the temperature sensor 3 fails abnormally, measures are taken to prohibit the engine from shutting down and reduce the load torque of the K0 clutch 1. When the temperature sensor 3 fails abnormally and the operating temperature of the K0 clutch 1 cannot be obtained in real time, comprehensive measures are taken to prohibit the engine from shutting down, request to reduce the input torque of the transmission and thus reduce the load torque of the K0 clutch 1, and can be supplemented by requesting the emergency engagement of the K0 clutch 1; avoiding the direct opening of the K0 clutch 1 can effectively improve the vehicle's endurance performance when the high-voltage battery is insufficient. Moreover, compared with the strategy of using a fixed value to replace the actual operating temperature, necessary comprehensive protection measures are added to reduce the risk of overheating and ablation damage of the K0 clutch 1.

[0039] Moreover, in the overheat protection method of this embodiment, a temperature compensation value Δt is also set for each level of temperature protection threshold; after taking the corresponding level of overheat protection measures, the overheat protection measures of this level are released only when the working temperature drops below the difference between the temperature protection threshold of the corresponding level and the temperature compensation value Δt. Of course, the temperature compensation values ​​Δt set for the temperature protection thresholds of each level can be the same or different; that is, the temperature protection thresholds of each level can use the same value of temperature compensation value Δt, or use different values ​​of temperature compensation value Δt.

[0040] A temperature compensation value Δt is set for each level of temperature protection threshold. After the operating temperature exceeds a certain level of the temperature protection threshold and corresponding overheating protection measures are taken, in the process of the operating temperature dropping accordingly, the overheating protection measures are not immediately lifted after the operating temperature is lower than the overheating protection measures, but the overheating protection measures are lifted after the operating temperature drops back to the temperature compensation value Δt below the overheating protection measures. This can improve the effect of the overheating protection measures and prevent frequent start and stop switching of the overheating protection measures during the control process.

[0041] The number of setting levels of the temperature protection threshold can be flexibly adjusted according to the control effect. In this embodiment, the above-mentioned multiple levels of temperature protection thresholds include a first-level temperature threshold T1, a second-level temperature threshold T2, and a third-level temperature threshold T3 that are successively increased; the multiple levels of overheating protection measures include a first-level overheating protection measure corresponding to the first-level temperature threshold T1, a second-level overheating protection measure corresponding to the second-level temperature threshold T2, and a third-level overheating protection measure corresponding to the third-level temperature threshold T3.

[0042] Based on the highest temperature threshold at which the K0 clutch 1 experiences severe overheating, three different temperature protection intervals are divided downward, and a temperature protection threshold is set at the upper limit position of each interval, thus forming three levels of temperature protection thresholds. Furthermore, a three-level overheating diagnosis and protection strategy can be implemented for the K0 clutch 1. By implementing corresponding different-level overheating protection measures in different temperature protection intervals, active early monitoring and handling are carried out in the early stage when the K0 clutch 1 overheats, thereby effectively improving the accuracy of overheating diagnosis of the K0 clutch 1 and the effectiveness of protection measures, and further improving the driving performance of the vehicle.

[0043] Correspondingly, the above-mentioned overheating protection measures at each level and the content of the measures are specifically set as follows:

[0044] The first-level overheating protection measure includes: prohibiting engine shutdown.

[0045] The second-level overheating protection measure includes: reducing the load torque of the K0 clutch 1 and increasing the engagement force of the K0 clutch 1.

[0046] The third-level overheating protection measure includes: disengaging the K0 clutch 1 and prohibiting engine startup.

[0047] In addition, in this embodiment, the overheating protection method also counts the number of times the operating condition temperature exceeds the third-level temperature threshold T3; that is, it counts the number of times the operating condition temperature exceeds the third-level temperature threshold T3, and accumulates each exceeded time as the over-temperature count N; at the same time, a count threshold Nc is set. When the over-temperature count N is greater than the count threshold Nc, the third-level overheating protection measure is maintained until the vehicle is powered off, and the over-temperature count N is cleared after the vehicle is powered off.

[0048] In each driving cycle when the vehicle is powered on and started, the maximum limit number of overheating occurrences (i.e., the count threshold Nc) at which the operating condition temperature of the K0 clutch 1 is allowed to exceed the third-level temperature threshold T3 is set. After the accumulated over-temperature count N exceeds the count threshold Nc, the third-level overheating protection measure is maintained, and the K0 clutch 1 is no longer allowed to continue operating, thereby effectively reducing the probability of the K0 clutch 1 being ablated due to severe overheating.

[0049] The following combines Figure 1 , Figure 2 , and details the process of specifically controlling the overheating of the K0 clutch 1 by the overheating protection method in this embodiment. The composition of the control system used to implement the overheating protection method is as Figure 2 shown, and the control unit 2 in the control system is described by taking the case of using a TCU as an example.

[0050] First, in the TCU, based on the highest temperature threshold of severe overheating of the K0 clutch 1, three different levels of temperature protection thresholds are sequentially divided downward, specifically including the first-level temperature threshold T1, the second-level temperature threshold T2, and the third-level temperature threshold T3; at the same time, temperature compensation values Δt are set for the temperature protection thresholds of each level. In addition, three fault codes can also be defined in the TCU, specifically the first-level fault code when the working condition temperature exceeds the first-level temperature threshold T1, the second-level fault code when the working condition temperature exceeds the second-level temperature threshold T2, and the third-level fault code when the working condition temperature exceeds the third-level temperature threshold T3; so as to transmit, store, and alarm the corresponding content of the fault code when the working condition temperature exceeds the temperature protection threshold.

[0051] At the same time, a counter 22 is set in the TCU to count the number of times the working condition temperature of the K0 clutch 1 exceeds T3 within the current vehicle power-on cycle; the initial value of the counter 22 is 0, and the counter 22 is automatically cleared whenever the vehicle power-on cycle ends and the vehicle powers off; at the same time, a storage count threshold Nc and the above-mentioned temperature protection thresholds of each level are set in the memory 21 of the TCU. Then the following control steps are carried out:

[0052] Step S1: The TCU collects the temperature signals of the oil pan temperature sensor 32 or the clutch temperature sensor 31 in real time, as well as the relevant signals of the working state of the K0 clutch 1; monitors the working state of the K0 clutch 1 in real time.

[0053] Step S2: The TCU judges the working state of the K0 clutch 1 according to the signals collected in S1 and calculates the working condition temperature of the K0 clutch 1. If the K0 clutch 1 is in the working state, go to step S3; if the K0 clutch 1 is in the non-working state, go to step S21, and the overheat protection logic of the K0 clutch 1 is not triggered.

[0054] Step S3: The TCU collects the operating state signals of the oil pan temperature sensor 32 and the clutch temperature sensor 31 in real time, and judges whether the temperature sensor 3 has a fault or abnormality; judges whether there is a fault or abnormality that affects the normal operation of the K0 clutch 1 according to the collected operating state signals. If so, go to step S31 to take comprehensive measures, the TCU sends a signal to prohibit shutdown to the HCU, prohibits the HCU from sending an engine shutdown instruction, and the HCU needs to respond to the TCU request; if not, go to step S4.

[0055] Step S4: The TCU monitors whether the working condition temperature of the K0 clutch 1 exceeds the first-level temperature threshold T1. If not, return to step S1; if so, go to step S5.

[0056] Step S5: TCU detects that the operating temperature of K0 clutch 1 exceeds the first-level temperature threshold T1, TCU stores the first-level fault code, and executes the first-level overheating protection measure, sending a shutdown prohibition signal to HCU, prohibiting HCU from sending an engine shutdown command, and HCU needs to respond to the TCU request.

[0057] Step S6: After the HCU responds to the TCU shutdown prohibition request, the TCU continues to monitor whether the operating temperature of the K0 clutch 1 exceeds the secondary temperature threshold T2. If not, the process proceeds to step S61; if yes, the process proceeds to step S7.

[0058] Step S61: TCU monitors whether the operating temperature of K0 clutch 1 is lower than T1-Δt (i.e., drops below T1-Δt). If yes, then go to step S62, release the first level overheat protection measure, and stop sending the shutdown prohibition signal to HCU; if no, then return to step S5.

[0059] Step S7: TCU detects that the operating temperature of K0 clutch 1 exceeds the secondary temperature threshold T2, TCU stores the secondary fault code, executes the secondary overheating protection measure, sends a torque reduction signal to HCU, and requests HCU to reduce the transmission input torque signal. HCU needs to respond to TCU request; at the same time, TCU uses high pressure to fully engage K0 clutch 1 in an emergency.

[0060] Step S8: After the HCU responds to the TCU torque reduction request and the K0 clutch 1 performs emergency engagement, the TCU continues to monitor whether the operating temperature of the K0 clutch 1 exceeds the third-level temperature threshold T3. If not, proceed to step S81; if yes, proceed to step S9.

[0061] Step S81: TCU monitors whether the operating temperature of K0 clutch 1 is lower than T2-Δt (i.e., drops below T2-Δt). If so, it proceeds to step S82, releases the secondary overheat protection measure, stops sending the torque reduction signal to HCU, and at the same time, the state of K0 clutch 1 exits the emergency engagement and turns to the normal control state; if not, it returns to step S7.

[0062] Step S9: TCU monitors that the operating temperature of K0 clutch 1 exceeds the third-level temperature threshold T3, TCU stores the third-level fault code, requests K0 clutch 1 to open urgently, and sends an engine start prohibition signal to HCU. HCU needs to respond to TCU request; at the same time, the over-temperature times N is increased by 1.

[0063] Step S10: TCU determines whether the over-temperature times N is greater than the counting threshold Nc. If not, it proceeds to step S101; if yes, it proceeds to step S11, keeps the three-level overheating protection measures unchanged, and the over-temperature times N does not increase.

[0064] Step S101: After the K0 clutch 1 performs emergency opening and the HCU responds to prohibit the engine from starting, the TCU monitors whether the operating temperature of the K0 clutch 1 is lower than T3-Δt (i.e., drops below T3-Δt). If so, the process proceeds to step S102, where the third-level overheating protection measures are released, the engine start prohibition signal is stopped from being sent to the HCU, and the request for emergency opening of the K0 clutch 1 is stopped; if not, the process returns to step S9.

[0065] In summary, the overheating protection method of the K0 clutch of the present embodiment sets multiple levels of temperature protection thresholds and corresponding multiple levels of overheating protection measures. During the overheating process of the K0 clutch 1, each time a level of temperature protection threshold is exceeded, there will be corresponding overheating protection measures to gradually strengthen the suppression of the temperature increase of the K0 clutch 1, which can effectively slow down the overheating process of the K0 clutch 1 and reduce the risk of severe overheating of the K0 clutch 1, thereby providing a K0 clutch 1 overheating protection technical solution that is beneficial to reducing the risk of overheating of the K0 clutch 1.

[0066] Embodiment 2

[0067] This embodiment relates to a hybrid electric vehicle, in which a K0 clutch 1 of the hybrid electric vehicle adopts the overheat protection method of the K0 clutch provided in the first embodiment.

[0068] By adopting the above-mentioned strategy of gradually strengthening overheating protection measures, hierarchical overheating diagnosis protection can be achieved. The TCU implements overheating response protection measures such as prohibiting engine shutdown, prohibiting engine start, requesting reduction of transmission input torque, requesting emergency engagement of K0 clutch 1 and requesting emergency opening of K0 clutch 1 in different temperature protection intervals. In the early stage of overheating of K0 clutch 1, pre-monitoring and intervention processing are carried out, which can effectively improve the accuracy of overheating diagnosis of K0 clutch 1 and the effectiveness of protection measures, thereby improving the driving performance of the vehicle.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for overheat protection of a K0 clutch, Features: The overheat protection method monitors the working state and operating temperature of the K0 clutch (1) in real time, and sets multiple levels of temperature protection thresholds for the K0 clutch (1), and multiple levels of overheat protection measures corresponding to each of the temperature protection thresholds for suppressing the temperature increase of the K0 clutch (1); When the K0 clutch (1) is in a working state and the operating temperature exceeds a temperature protection threshold of a certain level, taking the overheat protection measure of the corresponding level; The multiple levels of temperature protection thresholds include a first-level temperature threshold T1, a second-level temperature threshold T2, and a third-level temperature threshold T3 that are successively increased; the multiple levels of overheating protection measures include a first-level overheating protection measure corresponding to the first-level temperature threshold T1, a second-level overheating protection measure corresponding to the second-level temperature threshold T2, and a third-level overheating protection measure corresponding to the third-level temperature threshold T3; The first level overheat protection measure includes: prohibiting the engine from shutting down; the second level overheat protection measure includes: reducing the load torque of the K0 clutch (1) and increasing the engagement strength of the K0 clutch (1); the third level overheat protection measure includes: opening the K0 clutch (1) and prohibiting the engine from starting; In addition, the number of times the operating temperature exceeds the third-level temperature threshold T3 is counted and accumulated as the number of over-temperature times N, and a counting threshold Nc is set; when the number of over-temperature times N is greater than the counting threshold Nc, the third-level overheating protection measure is maintained until the vehicle is powered off, and the number of over-temperature times N is cleared after the vehicle is powered off.

2. The overheat protection method of the K0 clutch according to claim 1, Features: The operating temperature is obtained via a temperature sensor (3), wherein the temperature sensor (3) comprises a clutch temperature sensor (31) and / or an oil pan temperature sensor (32).

3. The overheat protection method of the K0 clutch according to claim 2, Features: When the temperature sensor (3) fails abnormally, the engine is prohibited from stopping and the load torque of the K0 clutch (1) is reduced.

4. The overheat protection method of the K0 clutch according to claim 1, Features: Setting a temperature compensation value Δt for each level of the temperature protection threshold; After the overheat protection measure of the corresponding level is taken, the overheat protection measure of this level is released only when the operating temperature drops below the difference between the temperature protection threshold of the corresponding level and the temperature compensation value Δt.

5. A hybrid electric vehicle, Features: The K0 clutch (1) of the hybrid vehicle adopts the overheat protection method of the K0 clutch according to any one of claims 1 to 4.

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