Dual clutch automatic transmission clutch thermal management method and thermal management system

Abstract

This invention relates to the field of automotive control technology, specifically to a thermal management method and system for a dual-clutch automatic transmission clutch. The method comprises the following steps: S1, collecting clutch operating parameters for the current cycle; S2, calculating the clutch temperature for the current cycle; S3, formulating a thermal management strategy based on the clutch temperature for the current cycle. The method for calculating the clutch temperature for the current cycle comprises the following steps: S21, calculating the clutch slippage power for the current cycle; S22, calculating the clutch lubrication power for the current cycle; S23, calculating the clutch temperature change value for the current cycle; S24, calculating the clutch temperature value for the current cycle. This application provides a simple clutch thermal management method. During vehicle operation, without disrupting the vehicle's operating state and without a clutch temperature sensor, the clutch temperature can be estimated and monitored in real time through oil temperature estimation, preventing clutch burn-out due to excessive thermal load under extreme operating conditions.

Description

Technical Field

[0001] This invention relates to the field of automotive control technology, specifically to a thermal management method and thermal management system for a dual-clutch automatic transmission clutch. Background Technology

[0002] Dual-clutch transmissions, as a type of automatic transmission, have two independent clutch systems. When the clutches engage, they transmit the engine's speed and torque to the input shaft and output power. The clutch control process ranges from macro-slip to micro-slip. During slip control, the speed difference generates slip work, causing the clutch to heat up. Excessive heat accumulation leads to an increase in transmission oil temperature and clutch plate temperature. When the temperature exceeds a critical value, it degrades drivability and, in severe cases, can cause clutch burning and damage to the transmission.

[0003] To ensure the transmission operates at its optimal level and prevent clutch damage due to overheating, the internal temperature of the transmission needs to be monitored and adjusted in real time to keep it within a reasonable temperature range. Due to cost considerations, only the oil pan temperature is measured by a temperature sensor; however, the clutch plate temperature and friction temperature cannot be detected in real time, thus preventing real-time monitoring of the clutch's own temperature.

[0004] To address this technical problem, a Chinese invention patent (CN110110377B) entitled "A Method for Estimating the Temperature of a Clutch Friction Plate" describes a method for estimating the temperature of a clutch friction plate. The method involves the following steps: First, data input: collecting relevant data such as engine speed, clutch torque, and ambient temperature; Second, slippage work calculation: calculating the slippage work of the driven plate and pressure plate using clutch torque, engine speed, and input shaft speed; Third, clutch temperature calculation: calculating the temperatures of the driven plate and pressure plate; Fourth, data output: outputting the temperature signal for clutch protection. While this method can estimate the clutch friction plate temperature by collecting engine speed, clutch torque, ambient temperature, and input shaft speed, it is not very accurate and the calculation is cumbersome. During vehicle operation, the collected parameters change in real time, and the method estimates a temperature value over a period of time. This method cannot accurately reflect the real-time temperature of the clutch, which is a disadvantage for subsequent control and adjustment. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide a thermal management method and thermal management system for a dual-clutch automatic transmission clutch.

[0006] The technical solution of this invention is: a thermal management method for a dual-clutch automatic transmission clutch, comprising the following steps:

[0007] S1. Set the calculation cycle and collect the clutch operating parameters for this cycle, including the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slip speed, and lubricant flow rate for this cycle.

[0008] S2. Calculate the clutch temperature for this cycle based on the above collected parameters;

[0009] S3. Compare the calculated clutch temperature for this cycle with the first set threshold and the second set threshold. If the clutch temperature for this cycle is less than or equal to the first set threshold, no adjustment is made.

[0010] If the clutch temperature in this cycle is greater than the first set threshold and less than or equal to the second set threshold, then the clutch is controlled to adjust according to the first control strategy.

[0011] If the clutch temperature in this cycle is greater than the second set threshold, the clutch is controlled to adjust according to the second control strategy.

[0012] The first set threshold is less than the second set threshold;

[0013] In step S2, the method for calculating the clutch temperature for this cycle is performed according to the following steps:

[0014] S21. Calculate the clutch slip power for this cycle based on the collected parameters;

[0015] S22. Calculate the clutch lubrication power for this cycle based on the collected parameters;

[0016] S23. Calculate the clutch temperature change value for this cycle based on the calculated clutch slippage power and clutch lubrication power for this cycle.

[0017] S24. The clutch temperature value for this cycle is calculated based on the clutch temperature change value for this cycle and the clutch temperature value for the previous cycle.

[0018] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, step S21, the method for calculating the clutch slippage power of the current cycle based on the collected parameters, includes: calculating the clutch slippage power of the current cycle according to the following formula.

[0019] P fric =T clu *n slip

[0020] Where: P fric —Clutch slippage power during this cycle;

[0021] T clu—Clutch torque for this cycle;

[0022] n slip —The clutch slippage speed in this cycle is the difference between the engine speed and the input shaft speed in this cycle.

[0023] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, step S22, the method for calculating the clutch lubrication power for the current cycle based on the collected parameters, includes: calculating the clutch lubrication power for the current cycle according to the following formula.

[0024] P lube =ΔT1*k

[0025] Where: P lube —Clutch lubrication power for this cycle;

[0026] ΔT1—The temperature difference caused by lubrication during this cycle;

[0027] k — thermal conductivity.

[0028] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, the temperature change difference caused by lubrication in the current cycle is calculated according to the following formula:

[0029] ΔT1=clu_temp_old-clu_lube_temp

[0030] Where: ΔT1——the temperature change difference caused by lubrication in this cycle;

[0031] clu_temp_old — Lubrication temperature in the previous cycle;

[0032] clu_lube_temp — Lubrication temperature for this cycle.

[0033] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, step S23, the method for calculating the clutch temperature change value for the current cycle based on the calculated clutch slippage power and clutch lubrication power for the current cycle includes: calculating the clutch static friction power for the current cycle based on the clutch slippage power and clutch lubrication power for the current cycle, and calculating the static friction power for the current cycle according to the following formula:

[0034]

[0035] Where: ΔT——clutch temperature change value in this cycle;

[0036] ΔP—Clutch static friction power in this cycle;

[0037] Δt — period time;

[0038] C—Specific heat capacity of lubricant;

[0039] Q—Lubricant flow rate for this cycle;

[0040] ρ — Lubricant density.

[0041] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, the method for calculating the static friction power of the current cycle based on the clutch slippage power and the clutch lubrication power of the current cycle includes: calculating according to the following formula:

[0042] ΔP=P fric -P lube

[0043] Where: ΔP——clutch static friction power in this cycle;

[0044] P fric —Clutch slippage power during this cycle;

[0045] P lube —Clutch lubrication power for this cycle.

[0046] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, step S24, the method for calculating the clutch temperature value of the current cycle based on the clutch temperature change value of the current cycle and the clutch temperature value of the previous cycle, includes:

[0047] T n =T n-1 +ΔT

[0048] Wherein: T n —Clutch temperature value for this cycle;

[0049] T n-1 —Clutch temperature value from the previous cycle;

[0050] ΔT — The change in clutch temperature during this cycle.

[0051] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, the first control strategy includes: sending a fault signal to the instrument to prompt the driver that the current clutch thermal load is too high; the controller controls the periodic fluctuation of clutch torque to cool the clutch; adjusting the lubrication flow according to temperature changes; and the controller increasing the fan speed.

[0052] According to the dual-clutch automatic transmission clutch thermal management method provided in this application, the second control strategy includes: increasing lubrication flow, increasing fan speed, and disengaging the clutch to interrupt power transmission.

[0053] This application also provides a dual-clutch automatic transmission clutch thermal management system, the management system being used to implement the above-described thermal management method, including...

[0054] The data acquisition module is used to collect the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slippage speed, and lubricant flow rate for the current cycle.

[0055] The calculation module calculates the clutch temperature value for this cycle based on the parameters collected by the data acquisition module.

[0056] The control module is used to compare the calculated clutch temperature value for the current cycle with a set threshold to formulate a corresponding thermal management strategy.

[0057] The advantages of this application are: 1. This application is a periodic sampling calculation with a high update frequency, short periodic sampling delay, fast response, and extremely high adjustment and control accuracy. This application calculates the clutch slip power of the current cycle first, then the clutch lubrication power of the current cycle, calculates the clutch temperature change value of the current cycle through the clutch slip power and the clutch lubrication power of the current cycle, and calculates the clutch temperature value of the current cycle based on the clutch temperature change value of the current cycle and the clutch temperature value of the previous cycle. The entire calculation process is simple. It can monitor the clutch temperature in real time by estimating the oil temperature without damaging the vehicle's operating state and without a clutch temperature sensor. This prevents the clutch from burning due to excessive heat load under extreme conditions. The control method is simple and easy to operate. There is no need to add extra monitoring equipment, and the cost of use is extremely low.

[0058] 2. The clutch slip power of this application is calculated by the clutch torque and clutch slip speed of this application. The clutch torque and clutch slip speed of this application are items that the vehicle controller needs to monitor in real time. The management method of this application does not require the addition of new monitoring equipment when obtaining the clutch slip power of this application. The method of real-time monitoring of the clutch slip power of this application is simple and convenient.

[0059] 3. The method of calculating the clutch lubrication power in this application is simple. It is calculated by the temperature change difference caused by lubrication in this cycle and the thermal conductivity. The temperature change difference caused by lubrication in this cycle is easy to obtain. The thermal conductivity is the product of the heat conducted per unit area when the temperature difference between the two sides is 1K and the flow rate of the coolant (lubricant in this application). It can be stored in the control system and called up during calculation, which is simple and convenient.

[0060] 4. The temperature change difference caused by lubrication in this cycle is the difference between the lubrication temperature of the previous cycle and the lubrication temperature of this cycle. In fact, it is the change in lubrication temperature. The lubrication temperature is obtained by a sensor that monitors the temperature of the lubricant. This is also an existing equipment structure. The actual calculation process does not require the investment of new equipment structure. The calculation method is simple and extremely convenient to use.

[0061] 5. The clutch temperature change value for this cycle is calculated based on the clutch static friction power, cycle time, lubricant specific heat capacity, lubricant flow rate, and lubricant density for this cycle. The calculation method is simple. The parameters such as cycle time, lubricant specific heat capacity, and lubricant density are pre-stored in the controller and are known values. The lubricant flow rate for this cycle can be calculated by flow velocity measurement or flow measurement device. These devices are conventional structures, and this application does not need to invest in new equipment. The method of obtaining parameters is simple and the calculation is convenient, which can accurately obtain the clutch temperature change value for this cycle.

[0062] 6. The static friction power of this application in this cycle is calculated based on the clutch slip friction power and clutch lubrication power in this cycle. The calculation method is simple. The clutch slip friction power and clutch lubrication power in this cycle can be easily obtained. The calculated static friction power of the clutch in this cycle is directly related to the clutch temperature change value in this cycle, and the clutch temperature can be quickly obtained.

[0063] 7. This application calculates the clutch temperature value of the current cycle by using the clutch temperature change value of the current cycle and the clutch temperature value of the previous cycle. Then, the clutch can be thermally managed based on the clutch temperature value of the current cycle. The overall method is simple and the logic is clear. It does not directly obtain the clutch temperature, but obtains the clutch temperature indirectly, which is simple and convenient.

[0064] 8. This application compares the clutch temperature value of the current cycle with the set threshold. When the first control strategy is required to control thermal management, it proves that the clutch temperature is too high at this time. However, the clutch can be cooled down by existing methods. The first control strategy is simple, easy to operate, and has a good cooling effect on the clutch.

[0065] 9. This application compares the clutch temperature value of the current cycle with the set threshold. When the second control strategy is required to control thermal management, it proves that the clutch temperature is too high. In addition to increasing the lubricant flow and fan speed in time, it is also necessary to open the clutch to interrupt power transmission, eliminate the heating factor from the root, and prevent clutch damage. This control strategy can protect the clutch in time and avoid problems caused by excessive heat load.

[0066] 10. This application also provides a management system that collects the required parameters through a data acquisition module. The data acquisition module is a sampling structure that is already present on the vehicle. Therefore, the management system of this application does not need to add sampling equipment. The calculation module analyzes and processes the data collected by the data sampling module to obtain the clutch temperature value for the week. The control module formulates a corresponding control strategy based on the clutch temperature value for the current cycle. The overall method is simple, easy to use, and has an excellent thermal management effect on the clutch, avoiding damage to the clutch caused by excessive thermal load.

[0067] This application presents a simple method for clutch thermal management. During vehicle operation, the clutch temperature can be estimated and monitored in real time through oil temperature estimation without disrupting the vehicle's operating state or requiring a clutch temperature sensor. This prevents the clutch from burning out due to excessive thermal load under extreme operating conditions. The clutch temperature is controlled in real time based on lubrication flow to maintain the transmission within its optimal operating temperature range, thereby improving transmission efficiency, enhancing power and comfort, and extending clutch lifespan. Attached Figure Description

[0068] Figure 1 : Flowchart of the thermal management method of this application. Detailed Implementation

[0069] Embodiments of the present invention are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0070] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0072] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0073] This application relates to a thermal management method and system for a dual-clutch automatic transmission clutch. The thermal management method of this application mainly obtains the clutch temperature (the clutch temperature in this application refers to the temperature of the clutch steel plate) in real time through indirect calculation or estimation. Then, the clutch temperature is compared with a set threshold, and the control strategy to be used for thermal management is determined based on the comparison result. The main purpose is to prevent the clutch from burning due to excessive heat load under extreme operating conditions. The clutch temperature is controlled in real time according to the lubrication flow to make the transmission operate in the optimal temperature range, improve transmission efficiency, improve power and comfort, and extend the service life of the clutch.

[0074] Specifically, the thermal management method of this application can be carried out according to the following steps:

[0075] S1. Set the calculation cycle and collect the clutch operating parameters for this cycle, including the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slip speed, and lubricant flow rate for this cycle.

[0076] The calculation method of this application is time periodic calculation, that is, assuming the set period is 10ms, when the vehicle is running, the corresponding calculation is performed once every 10ms, which is to calculate the instantaneous value at that moment, that is, real-time calculation and monitoring.

[0077] The lubrication temperature of this cycle refers to the temperature of the lubricant used to lubricate the clutch in this cycle. This temperature can be monitored by a temperature sensor that monitors the lubricant temperature. This temperature sensor is built into the vehicle itself, and the vehicle itself needs to monitor the lubricant temperature in real time.

[0078] The engine speed, input shaft speed, clutch torque, and clutch slippage speed of this cycle are all sampled and obtained through corresponding monitoring equipment. These parameters are also parameters that the vehicle controller needs to obtain in real time.

[0079] The lubricant flow rate in this cycle actually refers to the product of the lubricant flow rate and the cycle time. The flow rate can be monitored by the corresponding flow rate sensor, and the cycle time is actually the cycle time, such as 10ms mentioned above.

[0080] S2. Calculate the clutch temperature for this cycle based on the above collected parameters;

[0081] This application is based on the above-mentioned collected parameters to perform corresponding calculations to obtain the clutch temperature of the current cycle. The clutch temperature of the current cycle actually refers to the clutch steel plate temperature of the current cycle. The clutch temperature of the current cycle is a calculated value, not a measured value. It is calculated based on the above-mentioned collected parameters. The advantage of this is that there is no need to add new sampling equipment. During the operation of the vehicle, the clutch temperature can be estimated and monitored in real time by estimating the lubricant oil temperature without damaging the vehicle's operating state and without a clutch temperature sensor.

[0082] S3. Compare the calculated clutch temperature for this cycle with the first set threshold and the second set threshold;

[0083] This application sets a first set threshold and a second set threshold according to the vehicle clutch specifications and model. The first set threshold is less than the second set threshold. After calculating the clutch temperature of the current cycle in step S2, the clutch temperature of the current cycle can be compared with the first set threshold and the second set threshold.

[0084] If the clutch temperature in this cycle is less than or equal to the first set threshold, it proves that the clutch temperature is appropriate and no adjustment is needed.

[0085] If the clutch temperature in this cycle is greater than the first set threshold and less than or equal to the second set threshold, it indicates that the clutch temperature is too high and the clutch needs to be cooled down. However, if the clutch can still be operated, the clutch will be adjusted according to the first control strategy.

[0086] If the clutch temperature in this cycle exceeds the second set threshold, it indicates that the clutch temperature is too high and the clutch needs to be cooled down and the heating factor needs to be cut off. If the clutch cannot maintain normal operation, the clutch will be adjusted according to the second control strategy.

[0087] Among them, such as Figure 1 As shown, in step S2 of this application, the method for calculating the clutch temperature for this cycle can be performed according to the following steps:

[0088] S21. Calculate the clutch slip power for this cycle based on the collected parameters;

[0089] The clutch slip friction power in this cycle refers to the power of the clutch sliding friction in this cycle. The main reason for the clutch temperature rise is the frictional energy generated by the sliding friction. By calculating the clutch slip friction power in this cycle, the theoretical temperature rise of the clutch can be obtained.

[0090] S22. Calculate the clutch lubrication power for this cycle based on the collected parameters;

[0091] The clutch lubrication power of this cycle refers to the cooling power of the clutch by the lubricant during this cycle. In addition to lubricating the clutch, the lubricant flowing through the clutch also carries away some of the heat from the clutch, playing a certain cooling role. The clutch lubrication power is the main reason for the clutch cooling. By calculating the clutch lubrication power of this cycle, the theoretical cooling of the clutch can be obtained.

[0092] S23. Calculate the clutch temperature change value for this cycle based on the calculated clutch slippage power and clutch lubrication power for this cycle.

[0093] By obtaining the clutch slip power and clutch lubrication power for this cycle, we can obtain the actual heat change of the clutch. Based on this heat change, we can obtain the heat accumulated by the clutch in this cycle, and then we can calculate the clutch temperature change value for this cycle using this heat value.

[0094] S24. The clutch temperature value for the current cycle is calculated based on the clutch temperature change value for the current cycle and the clutch temperature value for the previous cycle.

[0095] The clutch temperature change value for the current cycle is obtained. Then, based on the clutch temperature value of the previous cycle, the clutch temperature value for the current cycle can be obtained. The clutch temperature value of the previous cycle is stored in the controller after it is calculated. When calculating the clutch temperature value for the current cycle, it can be directly called.

[0096] In some embodiments of this application, the method for calculating the clutch temperature value of the current cycle described above has been optimized. Specifically, in step S24 above, the method for calculating the clutch temperature value of the current cycle based on the clutch temperature change value of the current cycle and the clutch temperature value of the previous cycle is as follows:

[0097] T n =T n-1 +ΔT

[0098] Wherein: T n —Clutch temperature value for this cycle;

[0099] T n-1 —Clutch temperature value from the previous cycle;

[0100] ΔT — The change in clutch temperature during this cycle.

[0101] To obtain the clutch temperature value T for this cycle n We need to obtain the clutch temperature value T from the previous cycle. n-1 And the clutch temperature change value ΔT in this cycle, as mentioned above, the clutch temperature value T in the previous cycle. n-1 These are known parameters stored in the controller, so we only need to calculate the clutch temperature change value ΔT for this cycle.

[0102] In step S23 above, the method for calculating the clutch temperature change value for this cycle based on the calculated clutch slippage power and clutch lubrication power for this cycle is as follows: The clutch static friction power for this cycle is calculated based on the clutch slippage power and clutch lubrication power for this cycle, and then calculated according to the following formula:

[0103]

[0104] Where: ΔT——clutch temperature change value in this cycle;

[0105] ΔP—Clutch static friction power in this cycle;

[0106] Δt — period time;

[0107] C—Specific heat capacity of lubricant;

[0108] Q—Lubricant flow rate for this cycle;

[0109] ρ — Lubricant density.

[0110] In this process, the cycle time Δt is known (set to 10ms in this application); the specific heat capacity C of the lubricant is a characteristic parameter of the lubricant, which is obtained by looking up a table based on the material of the lubricant, and the manufacturer will generally provide the relevant parameters; similarly, the density ρ of the lubricant is also determined by the material of the lubricant, and the manufacturer will provide the parameters; the flow rate Q of the lubricant in this cycle can be determined based on the flow rate and cycle time of this cycle, and the flow rate can be obtained by the flow rate sensor in the lubricant equipment.

[0111] The static friction power ΔP of the clutch in this cycle is a value calculated using the clutch slip friction power and clutch lubrication power in this cycle. Specifically, the method for calculating the static friction power of the current cycle based on the clutch slip friction power and clutch lubrication power is as follows: The calculation is performed according to the following formula:

[0112] ΔP=P fric -P lube

[0113] Where: ΔP——clutch static friction power in this cycle;

[0114] P fric —Clutch slippage power during this cycle;

[0115] P lube —Clutch lubrication power for this cycle.

[0116] Therefore, to obtain the static friction power of the clutch in this cycle, it is necessary to calculate the slip friction power P of the clutch in this cycle. fric and the clutch lubrication power P in this cyclelube .

[0117] In step S21 above, the method for calculating the clutch slippage power for this cycle based on the collected parameters is as follows: The clutch slippage power for this cycle is calculated according to the following formula.

[0118] P fric =T clu *n slip

[0119] Where: P fric —Clutch slippage power during this cycle;

[0120] T clu —Clutch torque for this cycle;

[0121] n slip —The clutch slippage speed in this cycle is the difference between the engine speed and the input shaft speed in this cycle.

[0122] This week's clutch torque T clu and the clutch slippage speed n in this cycle slip These two parameters are the control parameters that the vehicle controller needs to monitor in real time. Therefore, these two parameters can be sampled using the existing monitoring equipment and then called.

[0123] In step S22 above, the method for calculating the clutch lubrication power for this cycle based on the collected parameters includes: calculating the clutch lubrication power for this cycle according to the following formula.

[0124] P lube =ΔT1*k

[0125] Where: P lube —Clutch lubrication power for this cycle;

[0126] ΔT1—The temperature difference caused by lubrication during this cycle;

[0127] k — thermal conductivity.

[0128] The thermal conductivity k is the heat transferred per unit area when the temperature difference between the two surfaces is 1K, multiplied by the cooling flow rate. The unit of thermal conductivity k is W / K, and it can be calculated using the following formula:

[0129] k = lube_flow * α

[0130] Where: k — thermal conductivity

[0131] lube_flow — Lubrication flow rate, obtained by looking up a table according to software settings;

[0132] α – a coefficient that characterizes the relationship between thermal conductivity and lubrication flow rate, obtained from bench experiments.

[0133] The temperature change difference caused by lubrication during this period is calculated using the following formula:

[0134] ΔT1=clu_temp_old-clu_lube_temp

[0135] Where: ΔT1——the temperature change difference caused by lubrication in this cycle;

[0136] clu_temp_old — Lubrication temperature in the previous cycle;

[0137] clu_lube_temp — Lubrication temperature for this cycle.

[0138] The lubrication temperature clu_temp_old of the previous cycle and the lubrication temperature clu_lube_temp of the current cycle are both obtained by temperature sensors that monitor the lubricant temperature.

[0139] Therefore, the clutch temperature for this cycle can be obtained through the steps described above.

[0140] In other embodiments of this application, the control strategy described above is optimized. Specifically, the first control strategy includes: sending a fault signal to the instrument to alert the driver that the current clutch thermal load is too high; the controller controls the periodic fluctuation of the clutch torque to cool the clutch; adjusting the lubrication flow according to temperature changes; and the controller increasing the fan speed.

[0141] The first control strategy is to ensure that the clutch can still operate normally, but the clutch needs to be cooled down. The current cooling methods mainly involve increasing the lubrication flow (i.e., increasing the flow of lubricant through the clutch so that the lubricant can carry away more heat), increasing the fan speed, and expanding the cooling effect of the fan on the clutch.

[0142] The second control strategy includes: increasing lubrication flow, increasing fan speed, and disengaging the clutch to interrupt power transmission.

[0143] The second control strategy is to interrupt the clutch operation when it can no longer continue to operate, to prevent the clutch from continuing to rub and heat up, and then to quickly cool down the clutch by adjusting the lubrication flow and fan speed.

[0144] In this embodiment, the first set threshold can be 130°C, and the second set threshold can be 140°C.

[0145] In addition, this application also provides a dual-clutch automatic transmission clutch thermal management system. The thermal management system of this application is mainly for implementing the above-mentioned dual-clutch automatic transmission clutch thermal management method, specifically including:

[0146] The data acquisition module is used to collect the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slippage speed, and lubricant flow rate for the current cycle.

[0147] The calculation module calculates the clutch temperature value for this cycle based on the parameters collected by the data acquisition module.

[0148] The control module is used to compare the calculated clutch temperature value for the current cycle with a set threshold to formulate a corresponding thermal management strategy.

[0149] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for thermal management of the clutch in a dual-clutch automatic transmission, characterized in that: Follow these steps: S1. Set the calculation cycle and collect the clutch operating parameters for this cycle, including the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slip speed, and lubricant flow rate for this cycle. S2. Calculate the clutch temperature for this cycle based on the above collected parameters; S3. Compare the calculated clutch temperature for this cycle with the first set threshold and the second set threshold. If the clutch temperature for this cycle is less than or equal to the first set threshold, no adjustment is made. If the clutch temperature in this cycle is greater than the first set threshold and less than or equal to the second set threshold, then the clutch is controlled to adjust according to the first control strategy. If the clutch temperature in this cycle is greater than the second set threshold, the clutch is controlled to adjust according to the second control strategy. The first set threshold is less than the second set threshold; In step S2, the method for calculating the clutch temperature for this cycle is performed according to the following steps: S21. Calculate the clutch slip power for this cycle based on the collected parameters; S22. Calculate the clutch lubrication power for this cycle based on the collected parameters; S23. Calculate the clutch temperature change value for this cycle based on the calculated clutch slippage power and clutch lubrication power for this cycle. S24. The clutch temperature value for the current cycle is calculated based on the clutch temperature change value for the current cycle and the clutch temperature value for the previous cycle. In step S22, the method for calculating the clutch lubrication power for this cycle based on the collected parameters includes: calculating the clutch lubrication power for this cycle according to the following formula. Where: P lube —Clutch lubrication power for this cycle; ΔT1—The temperature difference caused by lubrication during this cycle; k—thermal conductivity; The temperature change difference caused by lubrication in this cycle is calculated according to the following formula: Where: ΔT1——the temperature change difference caused by lubrication in this cycle; clu_temp_old — Lubrication temperature in the previous cycle; clu_lube_temp — Lubrication temperature for this cycle; In step S23, the method for calculating the clutch temperature change value for the current cycle based on the calculated clutch slippage power and clutch lubrication power for the current cycle includes: calculating the clutch static friction power for the current cycle based on the clutch slippage power and clutch lubrication power for the current cycle, and calculating the static friction power for the current cycle according to the following formula: Where: ΔT——clutch temperature change value in this cycle; ΔP—Clutch static friction power in this cycle; Δt — period time; C—Specific heat capacity of lubricant; Q—Lubricant flow rate for this cycle; ρ—Lubricant density; The method for calculating the static friction power of the current cycle based on the clutch slippage power and clutch lubrication power of the current cycle includes the following calculation formula: Where: ΔP——clutch static friction power in this cycle; P fric —Clutch slippage power during this cycle; P lube —Clutch lubrication power for this cycle.

2. The thermal management method for a dual-clutch automatic transmission clutch as described in claim 1, characterized in that: In step S21, the method for calculating the clutch slippage power for this cycle based on the collected parameters includes: calculating the clutch slippage power for this cycle according to the following formula. Where: P fric —Clutch slippage power during this cycle; T clu —Clutch torque for this cycle; n slip —The clutch slippage speed in this cycle is the difference between the engine speed and the input shaft speed in this cycle.

3. The thermal management method for a dual-clutch automatic transmission clutch as described in claim 1, characterized in that: In step S24, the method for calculating the clutch temperature value for the current cycle based on the clutch temperature change value for the current cycle and the clutch temperature value for the previous cycle includes: Wherein: T n —Clutch temperature value for this cycle; T n-1 —Clutch temperature value from the previous cycle; ΔT — The change in clutch temperature during this cycle.

4. The thermal management method for a dual-clutch automatic transmission clutch as described in claim 1, characterized in that: The first control strategy includes: sending a fault signal to the instrument to alert the driver that the current clutch thermal load is too high; the controller controls the periodic fluctuation of clutch torque to cool the clutch; adjusting the lubrication flow according to temperature changes; and the controller increasing the fan speed.

5. The thermal management method for a dual-clutch automatic transmission clutch as described in claim 1, characterized in that: The second control strategy includes: increasing lubrication flow, increasing fan speed, and disengaging the clutch to interrupt power transmission.

6. A clutch thermal management system for a dual-clutch automatic transmission, characterized in that: The management system is used to implement the thermal management method according to any one of claims 1 to 5, including, The data acquisition module is used to collect the lubrication temperature, engine speed, input shaft speed, clutch torque, clutch slippage speed, and lubricant flow rate for the current cycle. The calculation module calculates the clutch temperature value for this cycle based on the parameters collected by the data acquisition module. The control module is used to compare the calculated clutch temperature value for the current cycle with a set threshold to formulate a corresponding thermal management strategy.

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