A method and apparatus for engine stall prevention control of a vehicle

Abstract

The application discloses a vehicle engine anti-stalling control method and device. The vehicle comprises an automatic transmission, the automatic transmission comprises a hydraulic torque converter and a starting clutch, and the hydraulic torque converter comprises a turbine. When a wrong direction of vehicle shifting (WRD) condition occurs, the turbine may be reversed, so that the engine load rises, resulting in a risk of engine stall. Based on this, the application first identifies whether there is a turbine reverse condition after vehicle shifting. At the same time, whether the WRD condition occurs or not, the starting clutch is controlled to be engaged after vehicle shifting to improve the speed of vehicle power response. Further, when it is confirmed that there is a turbine reverse condition, the risk degree of vehicle stall is estimated. When the risk degree of vehicle stall meets the preset condition, it indicates that the risk degree of vehicle stall is high. At this time, the target oil pressure of the starting clutch is controlled to be reduced to open the starting clutch, cut off the power transmission, relieve the turbine reverse phenomenon and prevent the vehicle engine from stalling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a vehicle engine anti-stalling control method and device. BACKGROUND

[0002] Generally, a vehicle will have a gear shifting demand during driving. For a vehicle equipped with an automatic transmission, a wrong direction (WRD) condition may occur after gear shifting. In the WRD condition, the gear lever is in the D position, but the vehicle is driving backward, or the gear lever is in the R position, but the vehicle is driving forward. The WRD condition may cause the engine of the vehicle to stall.

[0003] Currently, after the WRD condition occurs, the start clutch is directly forced to delay for a certain time before starting to engage. This method alleviates the risk of engine stall to some extent, but this control method relies on a fixed waiting time, and the control has a certain lag. Moreover, there is still a potential risk of engine stall during the engagement of the start clutch after a certain delay.

[0004] Therefore, for the condition that the WRD condition causes the engine of the vehicle to stall, the current method makes the vehicle power response poor and still has the risk of causing the engine of the vehicle to stall. SUMMARY

[0005] To solve the above technical problems, the present application provides a vehicle engine anti-stalling control method and device, which can make the vehicle power response fast and prevent the engine of the vehicle from stalling.

[0006] To achieve the above purpose, the technical scheme provided by the present application is as follows:

[0007] In a first aspect, the present application provides a vehicle engine anti-stalling control method, the vehicle comprising an automatic transmission, the automatic transmission comprising a hydraulic torque converter and a start clutch, the hydraulic torque converter comprising a turbine, the method comprising:

[0008] identifying whether a turbine reverse rotation condition exists after gear shifting of the vehicle, and controlling the start clutch to engage after the gear shifting of the vehicle;

[0009] when the turbine reverse rotation condition exists, estimating the stalling risk degree of the vehicle;

[0010] when the stalling risk degree of the vehicle meets a preset condition, controlling to reduce the target oil pressure of the start clutch to open the start clutch and prevent the engine of the vehicle from stalling.

[0011] In a second aspect, the application provides a vehicle engine anti-stalling control device, the vehicle comprising an automatic transmission, the automatic transmission comprising a hydraulic torque converter and a launch clutch, the hydraulic torque converter comprising a turbine, the device comprising:

[0012] an identifying unit configured to identify whether a turbine reverse rotation condition exists after a gear shift of the vehicle and to control the launch clutch to be engaged after the gear shift of the vehicle;

[0013] an estimating unit configured to estimate a degree of stalling risk of the vehicle when the turbine reverse rotation condition exists;

[0014] a control unit configured to control a target oil pressure of the launch clutch to be reduced to open the launch clutch and prevent the vehicle engine from stalling when the degree of stalling risk of the vehicle meets a preset condition.

[0015] In a third aspect, the application provides an electronic device comprising:

[0016] one or more processors;

[0017] a memory device having one or more programs stored thereon,

[0018] when the one or more programs are executed by the one or more processors, the one or more processors implement any of the vehicle engine anti-stalling control methods.

[0019] In a fourth aspect, the application provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements any of the vehicle engine anti-stalling control methods.

[0020] According to the above technical solution, the application has the following beneficial effects:

[0021] The application provides a vehicle engine anti-flameout control method and device. The vehicle comprises an automatic transmission, the automatic transmission comprises a hydraulic torque converter and a start clutch, and the hydraulic torque converter comprises a turbine. When the vehicle is in a WRD working condition during gear shifting, the turbine may be reversed, so that the engine load rises, thereby causing the engine to have a flameout risk. Based on this, the application first identifies whether the turbine is reversed after the vehicle is shifted. At the same time, whether the WRD working condition occurs or not, the start clutch is controlled to be engaged after the vehicle is shifted, so as to improve the speed of the power response of the vehicle. Further, when it is confirmed that the turbine is reversed, the flameout risk degree of the vehicle is estimated. When the flameout risk degree of the vehicle meets a preset condition, it indicates that the flameout risk degree of the vehicle is high, at this time, the target oil pressure of the start clutch is controlled to be reduced, so as to open the start clutch, cut off the power transmission, relieve the turbine reverse phenomenon, thereby reducing the engine load torque, and preventing the vehicle engine from being flameout. In this way, the application also identifies the turbine reverse working condition and predicts the engine flameout risk degree, and when the engine flameout risk is high, the oil pressure is reduced in time, the start clutch is controlled to be opened, so as to prevent the vehicle engine from being flameout. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, below the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0023] Figure 1 A schematic diagram of power transmission of a continuously variable transmission is provided for the embodiments of the application.

[0024] Figure 2 A flowchart of a vehicle engine anti-flameout control method is provided for the embodiments of the application.

[0025] Figure 3 A schematic diagram of the change of the capacity coefficient bench test value under the turbine reverse working condition is provided for the embodiments of the application.

[0026] Figure 4 A flowchart of another vehicle engine anti-flameout control method is provided for the embodiments of the application.

[0027] Figure 5a A WRD control strategy schematic diagram is provided for the embodiments of the application.

[0028] Figure 5b A flameout control strategy schematic diagram is provided for the embodiments of the application.

[0029] Figure 6A structural schematic diagram of a vehicle engine anti-flameout control device provided by an embodiment of the present application is provided.

[0030] Figure 7 A schematic diagram of an electronic device provided by an embodiment of the present application is provided. DETAILED DESCRIPTION

[0031] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easy to understand, the embodiments of the present application are further described in detail below with reference to the drawings and specific embodiments.

[0032] In order to facilitate understanding and explanation of the technical solutions provided by the embodiments of the present application, the background art related to the embodiments of the present application is first introduced.

[0033] Generally, a vehicle has a gear shifting demand during driving. For a vehicle equipped with an automatic transmission, a wrong direction (WRD) condition may occur after gear shifting. In the WRD condition, the handle position is in the D gear, but the vehicle drives backward, or the handle position is in the R gear, but the vehicle drives forward. The WRD condition may cause the engine of the vehicle to flameout.

[0034] Currently, after the WRD condition occurs, the start clutch is directly forced to delay for a certain time before starting to engage. This method alleviates the risk of engine flameout to a certain extent, but this control method relies on a fixed waiting time, and the control has a certain hysteresis. Moreover, there is still a potential possibility of engine flameout during the engagement of the start clutch after the delay for a certain time. Therefore, for the condition that the WRD condition causes the engine of the vehicle to flameout, the current method makes the power response of the vehicle poor and still may cause the engine of the vehicle to flameout.

[0035] Based on this, this application provides a vehicle engine anti-stalling control method and device. The vehicle includes an automatic transmission, which includes a torque converter and a starting clutch. The torque converter includes a turbocharger. When the vehicle experiences a WRD (Wheel Reversal) condition during gear shifting, the turbocharger may reverse, causing an increase in engine load and potentially leading to engine stalling. Therefore, this application first identifies whether a turbocharger reversal condition exists after gear shifting. Simultaneously, regardless of whether a WRD condition occurs, the starting clutch is engaged after gear shifting to improve the vehicle's power response speed. Furthermore, when a turbocharger reversal condition is confirmed, the degree of engine stalling risk is estimated. When the engine stalling risk meets preset conditions, indicating a high risk, the target oil pressure of the starting clutch is reduced to disengage the clutch, cut off power transmission, alleviate turbocharger reversal, reduce engine load torque, and prevent engine stalling. Thus, this application also prevents engine stalling by promptly reducing oil pressure and disengaging the starting clutch when the engine stalling risk is high through turbocharger reversal identification and engine stalling risk prediction.

[0036] It is understandable that the shortcomings of the above solutions are the result of the applicant's practical experience and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of this application below should be considered contributions made by the applicant to the embodiments of this application.

[0037] In this embodiment, the vehicle includes an automatic transmission, which includes a torque converter and a starting clutch. The torque converter includes a turbine. As an optional example, the automatic transmission may be a continuously variable transmission (CVT). The following description will use a CVT as an example, but this does not constitute a limitation.

[0038] See Figure 1 , Figure 1 This is a schematic diagram of a continuously variable transmission (CVT) power transmission chain provided in an embodiment of this application. The following will be combined with... Figure 1 This section introduces the power transmission process of a continuously variable transmission (CVT).

[0039] A continuously variable transmission (CVT) is an automatic transmission that allows the gear ratio to be continuously varied within a certain range by changing the working radii of its two pulleys. For example... Figure 1As shown, the continuously variable transmission comprises a hydraulic torque converter 1, a launch clutch 2 (including a D-range clutch and an R-range clutch) and a steel belt system 3. The D-range clutch is a forward clutch and the R-range clutch is a reverse clutch. The launch clutch 2 has a friction disc with a friction surface. After the driver switches the gear to the D-range or the R-range, the launch clutch 2 synchronizes the input / output speed of the launch clutch by controlling the oil pressure, so that the power from the engine 4 can be transmitted to the wheel end of the wheel 6 through the turbine 11 of the hydraulic torque converter 1, the launch clutch 2 and the steel belt system 3. Therefore, the launch clutch 2 bears the functions of transmitting power, changing the direction of power transmission and cutting off power transmission.

[0040] The hydraulic torque converter 1 of the continuously variable transmission bears the function of transmitting the power of the engine to the transmission, and its good hydraulic characteristics can better attenuate the torque fluctuation between the engine and the transmission, improving the drivability. The hydraulic torque converter 1 mainly comprises a pump wheel assembly (connected to the engine flywheel), a turbine assembly (connected to the input end of the launch clutch), a lock-up clutch and a guide wheel assembly, and its control states include three states of torque conversion, slip and lock-up. In the torque conversion state, the engine drives the pump wheel to rotate through hydraulic action, and the power is output from the turbine end. The liquid flowing out of the turbine is changed in direction by the guide wheel and then flows back to the pump wheel to form a liquid circulation. In the slip state, the lock-up clutch pressure of the hydraulic torque converter gradually increases, and the engine and the turbine maintain a certain speed difference. At this time, the lock-up clutch is in a slip state. In the lock-up state, the engine speed is synchronized with the turbine speed, and the hydraulic torque converter becomes a rigid transmission at this time.

[0041] As shown in FIG. 1, Figure 1 The output end 31 of the steel belt system of the vehicle is connected to the main reducer 5. The turbine shaft of the hydraulic torque converter 1 of the continuously variable transmission is connected to the input shaft of the launch clutch 2 (D-range or R-range clutch), and the output end 21 of the launch clutch is connected to the driving pulley shaft of the steel belt system, so that the engine torque from the turbine shaft is transmitted to the wheel through the steel belt system-main reducer-differential and other components. Based on the mechanical characteristics of the launch clutch, when the transmission torque of the launch clutch exceeds the positive torque of the engine transmitted to the turbine during the engagement of the launch clutch, the rotational speeds at both ends of the launch clutch tend to be synchronized. The output end of the launch clutch is directly connected to the steel belt system-main reducer-differential-wheel and other components, and the moment of inertia is much larger than that of the input end of the clutch (the input end of the clutch is only connected to the turbine shaft, and during the engagement of the launch clutch, the hydraulic torque converter is in a hydraulic transmission state and is not directly connected to the engine), so during the engagement of the launch clutch, the input end speed of the launch clutch will gradually change to match the output end speed of the clutch (when the launch clutch speed is synchronized, the input / output end speed of the clutch meets the speed ratio relationship).

[0042] For the convenience of understanding the present application, a vehicle engine anti-flameout control method provided by an embodiment of the present application will be described below in conjunction with the accompanying drawings. As an optional example, the vehicle engine anti-flameout control method provided by the embodiment of the present application can be executed by a vehicle controller. For example, when the automatic transmission is a continuously variable transmission, the vehicle controller can be a continuously variable transmission control unit, which is not limited here.

[0043] Referring to Figure 2 FIG. 1 is a flowchart of a vehicle engine anti-flameout control method provided by an embodiment of the present application, as shown in the figure. Figure 2 As shown in the figure, the method can include S201-S203:

[0044] S201: identifying whether there is a turbine reverse rotation condition after vehicle gear shifting, and controlling the launch clutch to be engaged after vehicle gear shifting.

[0045] Based on the above, the transmission torque of the launch clutch will force the rotational speeds at both ends of the launch clutch to be synchronized, and the rotational speed at the input end of the launch clutch will gradually change to the rotational speed at the output end of the launch clutch. The applicant has found that, if the vehicle is in a WRD condition (i.e., a condition in which the vehicle driving direction does not match the vehicle handle position), at this time the transmission torque of the launch clutch will force the turbine to reverse rotation, so as to synchronize the rotational speeds at both ends of the launch clutch, which will cause the engine load to rapidly rise, and thus possibly cause the vehicle engine to flameout.

[0046] Some vehicle conditions in which the turbine may reverse rotation will be introduced below.

[0047] For example, during the forward driving of the vehicle at a low speed, the driver dials the handle to the R gear, at this time the vehicle will continue to drive forward due to inertia and gradually decelerate. Thus, the condition in which the vehicle driving direction does not match the vehicle handle position occurs. Since the vehicle is driving forward but the rotational speed gradually decreases, during this process the output shaft of the launch clutch is still rotating forward. Due to the action of the planetary gear set, the rotational speed at the input end of the launch clutch will form a certain speed ratio with the rotational speed at the output end, and the direction of the rotational speed changes until the rotational speeds at both ends of the R gear clutch are synchronized. The actual vehicle phenomenon is that the rotational speed at the input end of the launch clutch decreases to 0 and then rises, and finally maintains a certain speed ratio relationship with the rotational speed at the output end of the launch clutch. The clutch speed ratio relationship is determined by the clutch hardware structure. Under this condition, during the deceleration of the vehicle forward sliding, the rotational speed at the output end of the launch clutch and the vehicle speed are in a certain speed ratio relationship, which is determined by the steel belt speed ratio and the main reduction ratio, etc. Therefore, when the vehicle has not stopped, the rotational speed at the output end of the clutch also does not decrease to 0. After the engine torque switches the power transmission direction through the R gear clutch, a backward driving force will be formed on the wheels, which, together with the rolling resistance / wind resistance, etc. of the vehicle, hinders the vehicle from continuing to slide forward until the vehicle stops, and the engine can drive the vehicle to drive backward.

[0048] For example, after the driver parks on a sloping road surface, the driver releases the brake and the accelerator, and then selects the D range. The D range clutch starts to gradually engage. However, the vehicle may roll backward due to gravity. Thus, the vehicle driving direction may not match the vehicle handle position. During the gradual increase of the D range clutch torque, the primary / driven end speed of the launch clutch gradually synchronizes, but the primary end speed of the launch clutch may still be in the reverse direction (for example, the vehicle is rolling backward on a slope, but the engine driving torque is not enough to overcome the gravity). In this rolling condition, because the transmission chain is closed (because the D range clutch is locked), the turbine may be in the reverse direction, the engine load increases, and there is a potential risk of engine stall.

[0049] For another example, the driver selects the D range during the vehicle reverse process, the driver rolls backward on an uphill slope, and the vehicle driving direction may not match the vehicle handle position. Alternatively, in the low adhesion road surface (such as snow), the vehicle forward process causes the vehicle to reverse and slide, and the vehicle driving direction may not match the vehicle handle position.

[0050] The above-described conditions may cause the turbine to be in the reverse direction, which may cause the engine to stall and may potentially damage the transmission hardware.

[0051] Therefore, in the embodiments of the present application, whether the turbine is in the reverse direction is identified after the vehicle shifts, so that the subsequent engine stall risk prediction can be performed in time. In addition, after the vehicle shifts, the launch clutch is directly controlled to be engaged without delay, so that the speed of the vehicle power response can be improved without hysteresis.

[0052] In a possible implementation, the embodiments of the present application provide a specific implementation for identifying whether the turbine is in the reverse direction after the vehicle shifts, which includes the following steps.

[0053] According to the vehicle handle position, the transmission output shaft direction, and the turbine speed after the vehicle shifts, whether the turbine is in the reverse direction after the vehicle shifts is identified.

[0054] The vehicle handle position can represent the driver's intention, and the vehicle handle position includes the R range position and the D range position. The transmission output shaft direction is used to represent the vehicle driving direction. The transmission output shaft direction includes three directions: Forward, Standstill, and Reverse. When the transmission output shaft direction is Forward, the vehicle driving direction is Forward; when the output shaft direction is Standstill, the vehicle is stopped; and when the output shaft direction is Reverse, the vehicle driving direction is Reverse. The turbine speed is the current actual speed of the turbine, which can be collected by a corresponding sensor, which is not limited here.

[0055] It can be understood that, according to the vehicle handle position after the vehicle shifts and whether the direction of the gearbox output shaft is consistent, it can be determined whether the WRD condition occurs. Further, the turbine reverse rotation affects the turbine speed. Therefore, in combination with the vehicle handle position after the vehicle shifts, the direction of the gearbox output shaft and the turbine speed, it can be identified whether the turbine reverse rotation condition exists after the vehicle shifts.

[0056] In a specific implementation, according to the vehicle handle position after the vehicle shifts, the direction of the gearbox output shaft and the turbine speed, it can be identified whether the turbine reverse rotation condition exists after the vehicle shifts, including:

[0057] When the vehicle handle position after the vehicle shifts is different from the direction of the gearbox output shaft, the turbine speed has a zero-crossing phenomenon and the turbine speed change rate has opposite signs before and after the turbine speed zero-crossing, it is identified that the turbine reverse rotation condition exists after the vehicle shifts.

[0058] It can be understood that, when the vehicle handle position after the vehicle shifts is different from the direction of the gearbox output shaft, it indicates that the vehicle has the WRD condition. For example, the handle position is in D, but the direction of the gearbox output shaft is Reverse (i.e. when the vehicle is driving in reverse, the driver shifts the handle to D), or the handle position is in R, but the direction of the gearbox output shaft is Forward (i.e. when the vehicle is driving forward, the driver shifts the handle to R).

[0059] The "turbine speed has a zero-crossing phenomenon" means that the turbine speed first decreases to 0 and then gradually increases. This also indicates that the turbine speed change rate has opposite signs before and after the turbine speed zero-crossing, i.e. the turbine speed change rate before the turbine speed zero-crossing is negative, indicating that the turbine speed is decreasing, and the turbine speed change rate after the turbine speed zero-crossing is positive, indicating that the turbine speed is increasing. Generally, the hydraulic torque converter works in the traction condition, and when the starting clutch is not engaged, the turbine speed is affected by the engine torque to rotate in the positive direction at a speed close to the engine speed. When the starting clutch is in the engagement process, the turbine may start to reverse under the action of a larger torque, and in this process, the turbine speed first rotates in the positive direction and decreases to 0, and then reverses and gradually increases. The final speed depends on the output speed of the starting clutch and the speed ratio of the starting clutch. Therefore, on the basis of determining that the WRD condition occurs, by judging the "zero-crossing" phenomenon of the turbine speed and the positive and negative of the turbine speed change rate before and after the "zero-crossing", the turbine reverse rotation condition can be identified.

[0060] S202: When the turbine reverse rotation condition exists, the risk degree of the vehicle stalling is estimated.

[0061] After the vehicle shifts, if the turbine reverse rotation condition exists, the vehicle has a risk of stalling, and at this time, the risk degree of the vehicle stalling needs to be estimated. For example, real-time estimation can be performed to predict the possibility of the vehicle stalling in real time, and then the vehicle control can be performed in advance to prevent the vehicle engine from stalling.

[0062] In the embodiment of the present application, the start clutch is directly controlled to be engaged after the vehicle shifts gears. Then, there are two cases: the start clutch engagement process and the start clutch complete engagement. Since the engine of the vehicle may be at risk of being off in both cases, the present application provides a method for estimating the risk degree of the vehicle being off in both cases: during the start clutch engagement process and after the start clutch complete engagement.

[0063] In a specific implementation, the specific implementation of the method for estimating the risk degree of the vehicle being off includes A1-A2.

[0064] A1: During the engagement process of the start clutch, the engine estimated speed is calculated, and the risk degree of the vehicle being off is estimated according to the engine estimated speed, the engine target idle speed, and the engine current actual speed.

[0065] It can be understood that when the engine speed is lower than the engine idle speed, the risk degree of the vehicle being off is higher. Therefore, in order to realize the prediction of the risk degree of the vehicle being off, the engine estimated speed needs to be calculated first. The engine estimated speed is the estimated engine speed.

[0066] As an optional example, the engine estimated speed can be calculated through steps A11-A12.

[0067] A11: The engine speed change rate and the estimated clutch speed synchronization time are calculated, and the product of the engine speed change rate and the estimated clutch speed synchronization time is calculated.

[0068] A12: The sum of the engine current actual speed and the product is determined as the engine estimated speed.

[0069] If the engine speed change rate is represented by dω e / dt, the estimated clutch speed synchronization time is represented by t engd , the engine current actual speed is represented by ω e , and the engine estimated speed is represented by ω eCalc , then the calculation formula of the engine estimated speed obtained based on A11 and A12 is:

[0070]

[0071] Wherein, the engine speed change rate represents the change of the engine speed, the engine current actual speed can be obtained by a sensor, the engine estimated speed is a predicted value, and the estimated clutch speed synchronization time is the time required for the input speed and the output speed of the start clutch to be synchronized. Wherein, the input speed of the start clutch is the same as the turbine speed.

[0072] It can be understood that the engine estimated speed at the time of clutch speed synchronization is an estimated value. On the basis of confirming that the turbine reverse rotation condition occurs, the vehicle engine is prone to stall at the time of clutch speed synchronization, and therefore the engine estimated speed at the time of clutch speed synchronization is used to estimate the risk degree of vehicle stall in the embodiment of the application.

[0073] For example, the engine speed change rate in step A11 can be calculated by the following step A111:

[0074] A111: Calculate the engine speed change rate based on the engine output torque, the engine load torque, the engine moment of inertia and the pump wheel moment of inertia;

[0075] The engine load torque is calculated by the gearbox oil pump load torque, the capacity coefficient of the torque converter and the current actual engine speed. The capacity coefficient of the torque converter has a first functional relationship with the speed ratio of the torque converter and the gearbox oil temperature. The speed ratio of the torque converter is the ratio of the turbine speed to the current actual engine speed.

[0076] For example, the difference between the engine output torque and the engine load torque is calculated first, and then the sum of the engine moment of inertia and the pump wheel moment of inertia is calculated. The ratio of the difference to the sum is the engine speed change rate.

[0077] Based on this, the embodiment of the application provides a calculation formula of the engine speed change rate, as follows:

[0078]

[0079]

[0080] wherein, T e is the engine output torque, which can be obtained from the real vehicle Can network signal and is related to the position of the accelerator pedal (which can reflect the intention of the driver); J e is the sum of the engine moment of inertia and the pump wheel moment of inertia, which is a hardware parameter; ω e is the current actual engine speed, which can be obtained from the real vehicle Can network signal; dω e / dt is the engine speed change rate; ω Turb is the torque converter turbine shaft speed (i.e. turbine speed), which can be obtained from the gearbox speed sensor signal; the engine load torque includes the gearbox oil pump load torque and the torque converter hydraulic load torque, T TransLoad is the engine load torque, and therefore T TransLoad =T OilPumpLoad +Cω e 2 , T OilPumpLoadCω represents the transmission oil pump load torque, which can be obtained through bench testing and is related to factors such as transmission oil temperature. e 2 The hydraulic load torque of the torque converter is obtained from the torque converter capacity coefficient and the current actual engine speed. T is the transmission oil temperature, and f1 is the first functional relationship.

[0081] C is the capacity coefficient of the torque converter, a parameter related to its hydraulic characteristics. It can be obtained through bench testing and is related to the transmission oil temperature and the torque converter speed ratio, exhibiting a first-order functional relationship. (See also...) Figure 3 , Figure 3 This is a schematic diagram illustrating the change in the capacity coefficient bench test value under turbine reversal conditions, provided as an embodiment of this application. Under turbine reversal conditions, the bench test value of the hydraulic torque converter capacity coefficient is as follows: Figure 3 As shown, during turbo reversal, the C-coefficient increases with the increase of the torque converter speed ratio (the ratio of turbine speed to the current actual engine speed). When the speed ratio exceeds 1.3, the C-coefficient increases sharply, meaning that the higher the turbo reversal speed and the greater the value exceeding the engine speed, the greater the hydraulic load torque of the transmission on the engine.

[0082] For example, the estimated clutch speed synchronization time in step A11 can be calculated from steps A112-A113:

[0083] A112: Calculate the turbine speed change rate based on the turbine end output torque, clutch torque capacity, turbine shaft rotational inertia, and clutch input end rotational inertia.

[0084] For example, first calculate the difference between the turbine output torque and the clutch torque capacity, then calculate the sum of the turbine shaft rotational inertia and the clutch input rotational inertia. The ratio of this difference to the sum is the turbine speed change rate.

[0085] Based on this, during the engagement of the starting clutch, the rate of change of its input speed (turbine speed) can be estimated using the clutch input torque (i.e., turbine output torque) and the clutch torque capacity. The calculation formula is as follows:

[0086]

[0087] Among them, T Turb T is the output torque at the turbine end, which is the input torque at the clutch end; Clch J represents the torque capacity of the clutch; Turb J represents the turbine shaft rotational inertia, a hardware parameter. Clch ω is the moment of inertia at the clutch input end, a hardware parameter. Turb dω represents the turbine speed. Turbdt is the turbine speed change rate.

[0088] As an optional example, the turbine end output torque is calculated by the hydraulic torque converter capacity coefficient, the hydraulic torque converter torque ratio coefficient, the current actual engine speed and the hydraulic torque converter lock-up clutch torque capacity; the hydraulic torque converter lock-up clutch torque capacity is zero during the engagement of the vehicle starting clutch; the hydraulic torque converter torque ratio coefficient has a second function relationship f2 with the hydraulic torque converter speed ratio.

[0089] The turbine end output torque T Turb is related to the hydraulic characteristics of the hydraulic torque converter and the lock-up capacity of the hydraulic torque converter, and for example, the calculation formula of the turbine end output torque T Turb is as follows:

[0090] T Turb = KxCxω e 2 + T TCC

[0091]

[0092] Wherein, K is the hydraulic torque converter torque ratio coefficient, which belongs to the hydraulic characteristic parameters and can be obtained by bench test; C is the hydraulic torque converter capacity coefficient, which belongs to the hydraulic characteristic parameters; ω e is the current actual engine speed, which can be obtained by the real vehicle Can network signal; T TCC is the hydraulic torque converter lock-up clutch torque capacity, which is 0 during the engagement of the clutch.

[0093] As an optional example, the torque capacity of the clutch is calculated by the friction coefficient of the clutch friction plate, the pressure acting on the friction plate, the number of clutch friction pairs, the effective friction area of the clutch friction plate, the inner diameter of the clutch friction plate and the outer diameter of the clutch friction plate.

[0094] For example, the calculation formula of the torque capacity T Clch of the clutch is as follows:

[0095]

[0096] Wherein, T Clch is the torque capacity of the clutch; μ is the friction coefficient of the clutch friction plate, which belongs to the clutch hardware parameters; p is the pressure acting on the friction plate; n is the number of clutch friction pairs, which belongs to the clutch hardware parameters; A is the effective friction area of the clutch friction plate, which belongs to the clutch hardware parameters; R1 is the inner diameter of the clutch friction plate, which belongs to the clutch hardware parameters; R2 is the outer diameter of the clutch friction plate, which belongs to the clutch hardware parameters.

[0097] A113: Based on the turbine speed change rate, the turbine speed and the clutch output end speed, the estimated clutch speed synchronization time is calculated.

[0098] It can be seen that the product of the turbine speed change rate and the estimated clutch speed synchronization time is the gap between the turbine speed and the clutch output end speed, which can be represented by the following calculation formula:

[0099]

[0100] Wherein, t Engd is the estimated clutch speed synchronization time; ω Turb is the turbine speed; ω ClchOtpt is the clutch output end speed. Then, the estimated clutch speed synchronization time can be calculated based on the formula.

[0101] Then, after the engine speed change rate is calculated by step A111 and the estimated clutch speed synchronization time is calculated by steps A112-A113, the engine estimated speed can be calculated by A11 and A12. It can be understood that since the engine estimated speed ω eCalc is calculated, the turbine speed in the first function relationship and the second function relationship formula needs to be replaced by the turbine estimated speed. The turbine estimated speed is obtained from the turbine speed and the turbine speed change rate.

[0102] Then, the turbine estimated speed ω TurbCalc can be represented as:

[0103]

[0104] Based on this, the calculation formula of the engine estimated speed ω eCalc is as follows:

[0105]

[0106] It can be seen from the formula that the engine speed ω Turb at the clutch speed synchronization time can be estimated from the turbine speed ω ClchOtpt , the clutch output end speed ω e , the engine speed ω eCalc and the clutch pressure p.

[0107] After the engine estimated speed is calculated based on A11-A12, the present application provides a specific implementation method for estimating the engine estimated speed, the engine target idle speed and the engine current actual speed to estimate the engine estimated speed. The specific implementation method comprises:

[0108] When the engine estimated speed is lower than the engine target idle speed, or the engine current actual speed is lower than the engine target idle speed, the vehicle's engine stall risk degree is considered to meet the preset condition.

[0109] That is, the engine estimated speed ω ecalc is compared with the engine target idle speed, the lower the engine estimated speed is than the engine target idle speed, the higher the engine stall risk is, and the vehicle's engine stall risk degree is considered to meet the preset condition. In addition, if the engine current actual speed is already lower than the engine target idle speed, the engine stall risk is also considered to be high, and the vehicle's engine stall risk degree is considered to meet the preset condition. Based on this, the engine stall risk coefficient λ can be set, and the calculation formula is as follows:

[0110]

[0111] Wherein, λ is the engine stall risk coefficient, the lower the engine stall risk coefficient is, the greater the stall risk is; ω Idl is the engine target idle speed, which can be obtained from the vehicle Can network signal.

[0112] A2: After the starting clutch is completed, the engine current actual speed, the engine speed change rate, the turbine speed, the turbine rotation direction, the vehicle speed, and the engine load torque are used to estimate the vehicle's engine stall risk degree.

[0113] After the starting clutch is completed, the vehicle engine still has a stall risk. In an optional way, the engine current actual speed and the engine speed change rate can be used to estimate the vehicle's engine stall risk degree. In another optional way, the turbine speed, the turbine rotation direction, the vehicle speed, and the engine load torque can also be used to estimate the vehicle's engine stall risk degree.

[0114] Based on this, the embodiments of the present application provide a specific implementation mode for estimating the vehicle's engine stall risk degree according to the engine current actual speed, the engine speed change rate, the turbine speed, the turbine rotation direction, the vehicle speed, and the engine load torque, which includes:

[0115] When the engine current actual speed is less than or equal to the sum of the engine target idle speed and the speed threshold value and the engine speed change rate is negative, the vehicle's engine stall risk degree is considered to meet the preset condition;

[0116] Or,

[0117] When the turbine rotation direction is identified to be turbine reverse rotation according to the turbine speed, the engine load torque is greater than the torque threshold value, and the vehicle speed is greater than the vehicle speed threshold value, the vehicle's engine stall risk degree is considered to meet the preset condition.

[0118] The specific implementation of "estimating the stalling risk degree of the vehicle based on the current actual engine speed, the engine speed change rate" is that when the current actual engine speed is less than or equal to the sum of the target idle speed of the engine and the speed threshold value and the engine speed change rate is negative, the stalling risk degree of the vehicle is estimated to satisfy the preset condition.

[0119] Specifically, the stalling risk degree of the vehicle can be estimated based on the current actual engine speed and the target idle speed of the engine. It can be known that the stalling risk of the vehicle engine after the start clutch is completed is lower than that during the engagement of the start clutch. In order to make the estimation of the stalling risk degree of the vehicle after the start clutch is completed more accurate, the speed threshold value is set to be negative, and the sum of the target idle speed of the engine and the speed threshold value is calculated. Then, the current actual engine speed is compared with the sum, and when the current actual engine speed is less than or equal to the sum, it can be determined that the stalling risk degree of the vehicle is high. In addition, when the engine speed change rate is negative, it indicates that the engine speed is continuously decreasing below the target idle speed of the engine, at this time, it is determined that the stalling risk degree of the vehicle satisfies the preset condition, that is, the risk of the vehicle engine stalling is large, and the vehicle control needs to be performed.

[0120] In addition, the specific implementation of "estimating the stalling risk degree of the vehicle based on the turbine speed, the turbine rotation direction, the vehicle speed and the engine load torque" is that when the turbine rotation direction is identified to be turbine reverse rotation according to the turbine speed, the engine load torque is greater than the torque threshold value, and the vehicle speed is greater than the vehicle speed threshold value, the stalling risk degree of the vehicle is estimated to satisfy the preset condition.

[0121] Specifically, the turbine rotation direction can be identified according to the turbine speed, and if it is turbine reverse rotation, the vehicle engine stalling may occur. On this basis, the torque threshold value (positive value) and the vehicle speed threshold value are set, and when the engine load torque is greater than the torque threshold value and the vehicle speed is greater than the vehicle speed threshold value, it is determined that the stalling risk degree of the vehicle satisfies the preset condition. It can be understood that when the engine load torque is greater than the torque threshold value, it indicates that the engine capacity is insufficient to overcome the turbine reverse rotation, and then the stalling risk degree of the vehicle is high. In addition, in the above case, the higher the vehicle speed, the easier the vehicle engine stalling.

[0122] S203: When the stalling risk degree of the vehicle satisfies the preset condition, the target oil pressure of the start clutch is controlled to be reduced to open the start clutch and prevent the vehicle engine from stalling.

[0123] When the stalling risk degree of the vehicle satisfies the preset condition, it indicates that the engine stalling risk is large, at this time, the target oil pressure of the start clutch is controlled to be rapidly reduced to quickly open the clutch and cut off the power transmission, thereby preventing the vehicle engine from stalling.

[0124] In a possible implementation, the embodiment of the application provides a specific implementation of controlling the target oil pressure of the starting clutch, comprising the following steps of:

[0125] controlling the target oil pressure of the starting clutch of the vehicle to jump to a range near the half-coupling point of the clutch.

[0126] It can be understood that when it is identified that the engine stall risk is high, the target oil pressure of the starting clutch jumps to the range near the half-coupling point of the clutch. In this way, on the one hand, the clutch torque capacity is reduced by the reduction of the clutch oil pressure, so as to relieve the degree of turbine reverse rotation. On the other hand, the target oil pressure of the clutch is maintained near the half-coupling point, and the re-charging is no longer needed when the clutch is re-locked next time, so that the clutch oil pressure response can be improved, the clutch is quickly engaged, and the power transmission is restored.

[0127] In addition, when it is identified that the engine stall risk is low or the driver steps on the accelerator pedal (indicating that the driver has a strong starting intention), the anti-stall control strategy is exited, the starting clutch is quickly re-locked (i.e., the clutch is re-engaged), the power transmission is restored, the power transmission is timely restored, and the drivability is improved.

[0128] Based on the related content of S201-S203, the application provides a vehicle engine anti-stall control method. The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a starting clutch, and the torque converter includes a turbine. When the vehicle shifts in the WRD working condition, the turbine may be reversed, so that the engine load rises, and the engine has a stall risk. Based on this, the application first identifies whether the turbine reverse rotation working condition exists after the vehicle shifts. At the same time, whether the WRD working condition occurs or not, the starting clutch is controlled to be engaged after the vehicle shifts, so as to improve the speed of the vehicle power response. Further, when it is confirmed that the turbine reverse rotation working condition exists, the stall risk degree of the vehicle is estimated. When the stall risk degree of the vehicle meets the preset condition, it is indicated that the stall risk degree of the vehicle is high, at this time, the target oil pressure of the starting clutch is controlled to be reduced, so as to open the starting clutch, cut off the power transmission, relieve the turbine reverse rotation phenomenon, reduce the engine load torque, and prevent the vehicle engine from stalling. In this way, the application also identifies the turbine reverse rotation working condition and estimates the engine stall risk degree, and when the engine stall risk is high, the oil pressure is timely reduced, the starting clutch is controlled to be opened, and the vehicle engine is prevented from stalling.

[0129] Referring to Figure 4 , Figure 4 FIG. 2 is a flowchart of another vehicle engine anti-stall control method provided by the embodiment of the application. As shown in FIG. 2, the method comprises the following steps of: Figure 4As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed.

[0130] Referring to Figure 5a , Figure 5a is a schematic diagram of a WRD control strategy provided by the embodiment of the present application. As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5a As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5a As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5a As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5a As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed.

[0131] Referring to Figure 5b , Figure 5b is a schematic diagram of a WRD control strategy provided by the embodiment of the present application. As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5b As shown in the embodiment of the present application, first, the turbine reverse rotation condition is identified, and if the turbine reverse rotation condition occurs, the engine stall risk prediction is performed. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset condition is met), the clutch oil pressure is controlled at the half engagement point, otherwise the turbine reverse rotation condition identification is continuously performed. If the stall risk becomes low, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure is controlled to maintain the half engagement oil pressure, and at the same time, the engine stall risk prediction is continuously performed. Figure 5bThe vehicle engine anti-stalling control method provided by the embodiment of the application not only makes the vehicle control response faster, but also avoids the vehicle engine stalling as much as possible.

[0132] Based on the vehicle engine anti-stalling control method provided by the method embodiment, the embodiment of the application further provides a vehicle engine anti-stalling control device, which will be described below in combination with the drawings.

[0133] Referring to Figure 6 As shown in the figure, the figure is a structural schematic diagram of a vehicle engine anti-stalling control device provided by the embodiment of the application. The vehicle comprises an automatic transmission, the automatic transmission comprises a hydraulic torque converter and a launch clutch, the hydraulic torque converter comprises a turbine, and the turbine comprises a turbine wheel. Figure 6 As shown in the figure, the vehicle engine anti-stalling control device comprises:

[0134] An identification unit 601 is configured to identify whether there is a turbine reverse rotation condition after vehicle gear shifting, and control the launch clutch to be engaged after the vehicle gear shifting;

[0135] An estimation unit 602 is configured to estimate a stalling risk degree of the vehicle when the turbine reverse rotation condition exists.

[0136] A control unit 603 is configured to control the target oil pressure of the launch clutch to be reduced to open the launch clutch and prevent the vehicle engine from stalling when the stalling risk degree of the vehicle meets a preset condition.

[0137] In a possible implementation, the identification unit 601 comprises:

[0138] An identification sub-unit is configured to identify whether there is a turbine reverse rotation condition after vehicle gear shifting according to a vehicle handle position after vehicle gear shifting, a direction of a transmission output shaft, and a turbine speed.

[0139] In a possible implementation, the identification sub-unit is specifically configured to:

[0140] When the vehicle handle position after vehicle gear shifting is different from the direction of the transmission output shaft, the turbine speed has a zero-crossing phenomenon, and the turbine speed change rate has opposite signs before and after the turbine speed zero-crossing, it is identified that there is a turbine reverse rotation condition after vehicle gear shifting.

[0141] In a possible implementation, the estimation unit 602 comprises:

[0142] A first calculation sub-unit is configured to calculate an engine estimated speed in the engagement process of the launch clutch, and estimate the stalling risk degree of the vehicle according to the engine estimated speed, an engine target idle speed, and an engine current actual speed.

[0143] an estimation sub-unit, configured to estimate a risk degree of the vehicle being stalled according to the current actual engine speed, the engine speed change rate, the turbine speed, the turbine rotating direction, the vehicle speed and the engine load torque after the start clutch is completed to be engaged.

[0144] In a possible implementation, the first calculation sub-unit is specifically configured to:

[0145] estimate that the risk degree of the vehicle being stalled meets a preset condition when the estimated engine speed is lower than the target engine idle speed or the current actual engine speed is lower than the target engine idle speed;

[0146] The estimation sub-unit is specifically configured to:

[0147] estimate that the risk degree of the vehicle being stalled meets the preset condition when the current actual engine speed is less than or equal to a sum of the target engine idle speed and a speed threshold value and the engine speed change rate is negative;

[0148] or,

[0149] estimate that the risk degree of the vehicle being stalled meets the preset condition when the turbine rotating direction is identified to be turbine reverse rotation according to the turbine speed, the engine load torque is greater than a torque threshold value and the vehicle speed is greater than a vehicle speed threshold value.

[0150] In a possible implementation, the first calculation sub-unit comprises:

[0151] a second calculation sub-unit, configured to calculate the engine speed change rate and an estimated clutch speed synchronization time, and calculate a product of the engine speed change rate and the estimated clutch speed synchronization time;

[0152] a determination sub-unit, configured to determine a sum of the current actual engine speed and the product as an estimated engine speed;

[0153] The second calculation sub-unit further comprises:

[0154] a third calculation sub-unit, configured to calculate the engine speed change rate based on an engine output torque, an engine load torque, an engine moment of inertia and a pump wheel moment of inertia;

[0155] wherein the engine load torque is calculated by a gearbox oil pump load torque, a capacity coefficient of a torque converter and the current actual engine speed; the capacity coefficient of the torque converter has a first functional relationship with a speed ratio of the torque converter and a gearbox oil temperature, and the speed ratio of the torque converter is a ratio of the turbine speed to the current actual engine speed;

[0156] The second calculation subunit comprises:

[0157] The fourth calculation subunit is configured to calculate a turbine speed change rate based on a turbine end output torque, a torque capacity of the clutch, a turbine shaft rotational inertia, and a clutch input end rotational inertia;

[0158] The fifth calculation subunit is configured to calculate an estimated clutch speed synchronization time based on the turbine speed change rate, a turbine speed, and a clutch output end speed.

[0159] The turbine end output torque is calculated based on the torque converter capacity coefficient, a torque converter torque ratio coefficient, a current actual engine speed, and a torque converter lock clutch torque capacity. The torque converter lock clutch torque capacity is zero during the engagement of the vehicle starting clutch. The torque converter torque ratio coefficient has a second function relationship with the torque converter speed ratio.

[0160] The torque capacity of the clutch is calculated based on a friction coefficient of a clutch friction plate, a pressure acting on the friction plate, a number of clutch friction pairs, an effective friction area of the clutch friction plate, an inner diameter of the clutch friction plate, and an outer diameter of the clutch friction plate.

[0161] In a possible implementation, the control unit 603 is specifically configured to:

[0162] Control the target oil pressure step of the vehicle starting clutch to be in a range near a clutch half-joining point.

[0163] It should be noted that the specific implementation of each unit in the embodiment can refer to the related description in the above method embodiments. The division of units in the embodiment of the application is illustrative, and is only a logical function division. In actual implementation, another division mode can be used. Each functional unit in the embodiment of the application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. For example, in the above embodiment, the processing unit and the sending unit can be the same unit, or can be different units. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0164] The embodiment of the application further provides a computer readable medium, which stores a computer program, wherein the program is executed by a processor to implement the vehicle engine anti-flameout control method according to any one of the above.

[0165] Referring to Figure 7 , Figure 7 A schematic diagram of an electronic device according to an example embodiment of the present disclosure is shown.

[0166] Referring toFigure 7 An electronic device according to an example embodiment of the present disclosure includes a storage 71 having one or more programs stored thereon and one or more processors 72, the one or more programs, when executed by the one or more processors, causing the one or more processors to implement the vehicle engine stall prevention control method of any of the above. The vehicle includes an automatic transmission including a torque converter and a launch clutch, the torque converter including a turbine.

[0167] In an example embodiment of the present disclosure, the following steps can be implemented when the computer program is executed by the processor 72:

[0168] identifying whether a turbine reverse condition exists after a vehicle shift, and controlling the launch clutch to be engaged after the vehicle shift;

[0169] estimating a degree of stall risk of the vehicle when the turbine reverse condition exists;

[0170] controlling to reduce a target oil pressure of the launch clutch to open the launch clutch and prevent the vehicle engine from stalling when the degree of stall risk of the vehicle satisfies a preset condition.

[0171] From the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps of the above-mentioned example method can be implemented by means of software and necessary universal hardware platforms. Based on such an understanding, the technical solutions of the present application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) execute the methods described in the various embodiments or some parts of the embodiments.

[0172] It should be noted that the various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be mutually referred to. For the method disclosed by the embodiments, since it corresponds to the system disclosed by the embodiments, the description is relatively simple, and the relevant parts can be referred to the system part.

[0173] It is also to be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component" can include a combination of two or more components, and the term "an element" can include comparable reference to a plurality of elements.

[0174] The foregoing description of the disclosed embodiments enables a person skilled in the art to implement or use the application. Numerous modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preventing engine stalling in a vehicle, characterized in that, The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a starting clutch, the torque converter includes a turbine, and the method includes: Identify whether there is turbo reversal after the vehicle shifts gears, and control the engagement of the starting clutch after the vehicle shifts gears; When the turbo reverse operation occurs, estimate the risk of the vehicle stalling. When the risk of the vehicle stalling meets the preset conditions, the target oil pressure of the starting clutch is reduced to open the starting clutch and prevent the vehicle engine from stalling. The estimated risk level of vehicle stalling includes: During the engagement of the starting clutch, the estimated engine speed is calculated, and based on the estimated engine speed, the target engine idle speed, and the current actual engine speed, the risk of the vehicle stalling is estimated. After the starting clutch is engaged, the risk of the vehicle stalling is estimated based on the engine's current actual speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed, and engine load torque. The calculation of the estimated engine speed includes: Calculate the engine speed change rate and the estimated clutch speed synchronization time, and calculate the product of the engine speed change rate and the estimated clutch speed synchronization time; The sum of the current actual engine speed and the product is determined as the estimated engine speed; The calculation of the estimated clutch speed synchronization time includes: The turbine speed change rate is calculated based on the turbine end output torque, clutch torque capacity, turbine shaft rotational inertia, and clutch input end rotational inertia. Based on the turbine speed change rate, turbine speed, and clutch output speed, the estimated clutch speed synchronization time is calculated.

2. The method according to claim 1, characterized in that, The method of identifying whether the turbocharger reverses after a vehicle shifts gears includes: Based on the position of the vehicle's gear lever, the direction of the transmission output shaft, and the turbine speed after the vehicle shifts gears, it can be determined whether the turbine reverses after the vehicle shifts gears.

3. The method according to claim 2, characterized in that, The method of identifying whether there is turbo reversal after a gear shift based on the vehicle's shift lever position, transmission output shaft direction, and turbo speed includes: When the position of the vehicle's shift lever is different from the direction of the transmission output shaft after the vehicle shifts gears, the turbine speed crosses zero, and the turbine speed change rate has opposite signs before and after the turbine speed crosses zero, the turbine reverses its rotational speed after the vehicle shifts gears.

4. The method according to claim 1, characterized in that, The step of estimating the risk of vehicle stalling based on the estimated engine speed, target engine idle speed, and current actual engine speed includes: When the estimated engine speed is lower than the engine target idle speed, or when the current actual engine speed is lower than the engine target idle speed, the estimated risk of the vehicle stalling meets the preset conditions. The method of estimating the risk of vehicle stalling based on the current actual engine speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed, and engine load torque includes: When the current actual engine speed is less than or equal to the sum of the engine target idle speed and the speed threshold, and the engine speed change rate is negative, the estimated risk level of the vehicle stalling meets the preset conditions. or, When the turbine rotation direction is identified as turbine reversal based on the turbine speed, the engine load torque is greater than the torque threshold, and the vehicle speed is greater than the vehicle speed threshold, the estimated risk of the vehicle stalling meets the preset conditions.

5. The method according to claim 1, characterized in that, The calculation of the engine speed change rate includes: Calculate the rate of change of engine speed based on engine output torque, engine load torque, engine moment of inertia and pump wheel moment of inertia; The engine load torque is calculated from the transmission oil pump load torque, the torque converter capacity coefficient, and the current actual engine speed; the torque converter capacity coefficient has a first functional relationship with the torque converter speed ratio and the transmission oil temperature; and the torque converter speed ratio is the ratio of the turbine speed to the current actual engine speed.

6. The method according to claim 1, characterized in that, The calculation of the estimated clutch speed synchronization time also includes: The turbine-end output torque is calculated from the torque converter capacity coefficient, torque converter torque ratio coefficient, the current actual engine speed, and torque converter lock-up clutch torque capacity; the torque converter lock-up clutch torque capacity is zero during the engagement of the vehicle's starting clutch; the torque converter torque ratio coefficient has a second functional relationship with the torque converter speed ratio; The torque capacity of the clutch is calculated from the friction coefficient of the clutch friction plate, the pressure acting on the friction plate, the number of clutch friction pairs, the effective friction area of ​​the clutch friction plate, the inner diameter of the clutch friction plate, and the outer diameter of the clutch friction plate.

7. The method according to claim 1, characterized in that, The control of reducing the target oil pressure of the starting clutch includes: The target oil pressure of the vehicle's starting clutch is controlled to step up to the vicinity of the clutch half-engagement point.

8. A vehicle engine anti-shutdown control device, characterized in that, The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a starting clutch, the torque converter includes a turbine, and the device includes: The identification unit is used to identify whether there is a turbo reverse condition after the vehicle shifts gears, and to control the engagement of the starting clutch after the vehicle shifts gears. The prediction unit is used to predict the risk of engine stalling of the vehicle when the turbo reverse operation occurs. The control unit is used to control the reduction of the target oil pressure of the starting clutch when the risk level of the vehicle stalling meets the preset conditions, so as to open the starting clutch and prevent the vehicle engine from stalling. The estimated risk level of vehicle stalling includes: During the engagement of the starting clutch, the estimated engine speed is calculated, and based on the estimated engine speed, the target engine idle speed, and the current actual engine speed, the risk of the vehicle stalling is estimated. After the starting clutch is engaged, the risk of the vehicle stalling is estimated based on the engine's current actual speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed, and engine load torque. The calculation of the estimated engine speed includes: Calculate the engine speed change rate and the estimated clutch speed synchronization time, and calculate the product of the engine speed change rate and the estimated clutch speed synchronization time; The sum of the current actual engine speed and the product is determined as the estimated engine speed; The calculation of the estimated clutch speed synchronization time includes: The turbine speed change rate is calculated based on the turbine end output torque, clutch torque capacity, turbine shaft rotational inertia, and clutch input end rotational inertia. Based on the turbine speed change rate, turbine speed, and clutch output speed, the estimated clutch speed synchronization time is calculated.

9. An electronic device, characterized in that, include: One or more processors; Storage device, on which one or more programs are stored, When the one or more programs are executed by the one or more processors, the one or more processors implement the vehicle engine anti-shutdown control method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, It stores a computer program, wherein the computer program, when executed by a processor, implements the vehicle engine anti-shutdown control method as described in any one of claims 1-7.

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