Anti-flameout control method and device for vehicle engine

Abstract

The invention discloses a vehicle engine flameout prevention control method and device, a 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 the WRD working condition of wrong direction occurs during vehicle gear shifting, a turbine may reversely rotate, so that the load of an engine is increased, and the risk of flameout of the engine is caused. On the basis, whether the turbine reverse rotation working condition exists or not after vehicle gear shifting is firstly recognized. Meanwhile, no matter whether the WRD working condition occurs or not, the starting clutch is controlled to be connected after gear shifting of the vehicle, so that the power response speed of the vehicle is increased. And furthermore, when it is confirmed that the turbine reverse rotation working condition exists, the flameout risk degree of the vehicle is pre-estimated. When the flameout risk degree of the vehicle meets the preset condition, it is indicated that the flameout 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 power transmission, relieve the turbine reverse rotation phenomenon and prevent the vehicle engine from stalling.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a vehicle engine anti-stall control method and device. Background Art

[0002] Usually, a vehicle will need to shift gears while driving. After a vehicle equipped with an automatic transmission shifts gears, a Wrong Direction (WRD) condition may occur. In a WRD condition, the handle is in D gear but the vehicle is moving backward, or the handle is in R gear but the vehicle is moving forward. The WRD condition may cause the vehicle engine to stall.

[0003] At present, when the WRD condition occurs, the starting clutch will be forced to engage after a certain delay. This method alleviates the risk of engine stalling to a certain extent, but this control method relies on a fixed waiting time and has a certain hysteresis. Moreover, there is still a potential possibility of engine stalling during the starting clutch engagement process after a certain delay.

[0004] Therefore, in the case where the WRD condition causes the vehicle engine to stall, the current method causes the vehicle power response to be poor and may still cause the vehicle engine to stall. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a vehicle engine anti-stall control method and device, which can enable the vehicle power to respond quickly and prevent the vehicle engine from stalling.

[0006] In order to achieve the above objectives, the technical solutions provided by this application are as follows:

[0007] In a first aspect, the present application provides a vehicle engine anti-stall control method, wherein 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:

[0008] identifying whether a turbine reversal condition exists after a vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears;

[0009] When the turbine reverse working condition exists, estimating the risk of flameout of the vehicle;

[0010] When the flameout risk level of the vehicle meets a preset condition, the target oil pressure of the starting clutch is controlled to be reduced to open the starting clutch to prevent the vehicle engine from flameout.

[0011] In a second aspect, the present application provides a vehicle engine anti-stall control device, the vehicle includes an automatic transmission, the automatic transmission includes a hydraulic torque converter and a starting clutch, the hydraulic torque converter includes a turbine, and the device includes:

[0012] an identification unit, used for identifying whether a turbine reversal condition exists after the vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears;

[0013] an estimating unit, configured to estimate a flameout risk level of the vehicle when the turbine reverse working condition exists;

[0014] The control unit is used for controlling the reduction of the target oil pressure of the starting clutch to open the starting clutch to prevent the vehicle engine from stalling when the risk level of the vehicle stalling meets a preset condition.

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

[0016] one or more processors;

[0017] a storage 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-stall control methods.

[0019] In a fourth aspect, the present 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-stall control methods described above.

[0020] Through the above technical solution, it can be seen that the present application has the following beneficial effects:

[0021] The present application provides a method and device for preventing a vehicle engine from stalling. 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 gears and a WRD condition occurs, the turbine may reverse, causing the engine load to increase, thereby causing the engine to stall. Based on this, the present application first identifies whether there is a turbine reversal condition after the vehicle shifts gears. At the same time, regardless of whether the WRD condition occurs, the starting clutch is controlled to engage after the vehicle shifts gears to increase the speed of the vehicle's power response. Further, when it is confirmed that there is a turbine reversal condition, the stall risk level of the vehicle is estimated. When the stall risk level of the vehicle meets the preset conditions, it indicates that the stall risk level of the vehicle 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, and alleviate the turbine reversal phenomenon, thereby reducing the engine load torque and preventing the vehicle engine from stalling. In this way, the present application also reduces the oil pressure in time when the engine stall risk is high, controls the starting clutch to open, and prevents the vehicle engine from stalling by identifying the turbine reversal condition and predicting the engine stall risk level. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of a continuously variable transmission power transmission chain provided in an embodiment of the present application;

[0024] Figure 2 A flow chart of a vehicle engine anti-stall control method provided in an embodiment of the present application;

[0025] Figure 3 A schematic diagram of the change of the capacity coefficient bench test value under a turbine reverse working condition provided in an embodiment of the present application;

[0026] Figure 4 A flow chart of another vehicle engine anti-stall control method provided in an embodiment of the present application;

[0027] Figure 5a A schematic diagram of a WRD control strategy provided in an embodiment of the present application;

[0028] Figure 5b A schematic diagram of an anti-stall control strategy provided in an embodiment of the present application;

[0029] Figure 6A schematic diagram of the structure of a vehicle engine anti-stall control device provided in an embodiment of the present application;

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

[0031] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

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

[0033] Usually, a vehicle will need to shift gears while driving. After a vehicle equipped with an automatic transmission shifts gears, a Wrong Direction (WRD) condition may occur. In a WRD condition, the handle is in D gear but the vehicle is moving backward, or the handle is in R gear but the vehicle is moving forward. The WRD condition may cause the vehicle engine to stall.

[0034] At present, after the WRD condition occurs, the starting clutch will be forced to delay for a certain period of time before engaging. This method alleviates the risk of engine stalling to a certain extent, but this control method relies on a fixed waiting time and has a certain hysteresis in the control. Moreover, there is still a potential possibility of engine stalling during the starting clutch engagement process after a certain delay. Therefore, in the case of vehicle engine stalling caused by WRD condition, the current method makes the vehicle power response poor and may still cause the vehicle engine to stall.

[0035] Based on this, the embodiment of the present application provides a method and device for preventing a vehicle engine from stalling, wherein 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 gears and a WRD condition occurs, the turbine may reverse, causing the engine load to increase, thereby causing the engine to stall. Based on this, the present application first identifies whether there is a turbine reversal condition after the vehicle shifts gears. At the same time, regardless of whether the WRD condition occurs, the starting clutch is controlled to engage after the vehicle shifts gears to increase the speed of the vehicle's power response. Further, when it is confirmed that there is a turbine reversal condition, the degree of stalling risk of the vehicle is estimated. When the degree of stalling risk of the vehicle meets the preset conditions, it indicates that the degree of stalling risk of the vehicle 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, and alleviate the turbine reversal phenomenon, thereby reducing the engine load torque and preventing the vehicle engine from stalling. In this way, the present application also reduces the oil pressure in time when the risk of engine stalling is high, and controls the starting clutch to open, through the identification of the turbine reversal condition and the prediction of the degree of engine stalling risk.

[0036] It is understandable that the defects in the above solutions are the results obtained by the applicant after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in the embodiments of the present application for the above problems below should be the contributions made by the applicant to the embodiments of the present application during the application process.

[0037] In the embodiment of the present application, the vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a starting clutch, and the torque converter includes a turbine. As an optional example, the automatic transmission may be a continuously variable transmission, and the following description will be made by taking the automatic transmission as an example, which does not constitute a limitation.

[0038] See also Figure 1 , Figure 1 A schematic diagram of a continuously variable transmission power transmission chain provided in an embodiment of the present application. Figure 1 The power transmission process of the continuously variable transmission is introduced.

[0039] A continuously variable transmission is an automatic transmission that can achieve continuous changes in the transmission ratio within a certain range by changing the working radius of the two pulleys. Figure 1As shown, the continuously variable transmission includes a torque converter 1, a starting clutch 2 (including a D gear clutch and an R gear clutch) and a steel belt system 3. Among them, the D gear clutch is a forward clutch, and the R gear clutch is a reverse clutch. There is a friction disk on the starting clutch 2, and the friction disk has a friction surface. After the driver switches the gear to the D gear or the R gear, the starting clutch 2 controls the oil pressure to complete the synchronization of the speed of the input / output end of the starting clutch, 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 torque converter 1, the starting clutch 2 and the steel belt system 3. Therefore, the starting clutch 2 plays the role of transmitting power, changing the direction of power transmission and cutting off power transmission.

[0040] The torque converter 1 of the continuously variable transmission is responsible for transmitting the power of the engine to the transmission. Its good hydraulic characteristics can effectively attenuate the torque fluctuation between the engine and the transmission and improve the drivability. The torque converter 1 mainly includes a pump wheel assembly (connected to the engine flywheel), a turbine assembly (connected to the input end of the starting clutch), a locking clutch and a guide wheel assembly. Its control state is divided into three states: torque conversion, slip and lock. In the torque conversion condition, the engine drives the pump wheel to drive the turbine to rotate through the hydraulic action, and the power is output from the turbine end. The liquid flowing out of the turbine will flow back to the pump wheel after changing the direction through the guide wheel to form a liquid cycle. In the slip condition, the pressure of the torque converter lock clutch gradually increases, and the engine and the turbine maintain a certain speed difference. At this time, the lock clutch is in a slip state. In the locking condition, the engine speed is synchronized with the turbine speed. At this time, the torque converter becomes a rigid transmission.

[0041] like Figure 1 As shown, the output end 31 of the steel belt system of the vehicle is connected to the main reducer 5. The turbine shaft of the torque converter 1 of the continuously variable transmission is connected to the input shaft of the starting clutch 2 (D gear or R gear clutch), and the output end 21 of the starting 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 starting clutch, during the engagement process of the starting clutch, when the starting clutch torque value exceeds the positive torque transmitted from the engine to the turbine, the speed of the two ends of the starting clutch will be synchronized. The output end of the starting clutch is directly connected to the steel belt system-main reducer-differential-wheel and other components, and the moment of inertia is far greater than the input end of the clutch (the input end of the clutch is only connected to the turbine shaft, and during the engagement process of the starting clutch, the torque converter is in a hydraulic transmission state and is not directly connected to the engine). Therefore, during the engagement process of the starting clutch, the speed of the input end of the starting clutch will gradually change to match the speed of the output end of the clutch (when the speed of the starting clutch is synchronized, the speed of its input / output end conforms to the clutch speed ratio relationship).

[0042] In order to facilitate understanding of the present application, a vehicle engine flameout prevention control method provided by an embodiment of the present application is described below in conjunction with the accompanying drawings. As an optional example, the vehicle engine flameout prevention control method provided by an 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] See also Figure 2 As shown in FIG. 1 , this figure is a flow chart of a vehicle engine anti-stall control method provided by an embodiment of the present application. Figure 2 As shown, the method may include S201-S203:

[0044] S201: Identify whether there is a turbine reversal condition after the vehicle shifts gears, and control the start clutch to engage after the vehicle shifts gears.

[0045] Based on the above, it can be known that the torque transmission of the starting clutch will cause the speeds of both ends of the starting clutch to be synchronized, and the speed of the input end of the starting clutch will gradually change to the speed of the output end of the starting clutch. The applicant has found through research that if the vehicle is in the WRD condition (i.e., the condition where the vehicle's driving direction does not match the position of the vehicle handle), the torque transmission of the starting clutch will force the turbine to reverse to achieve the speed synchronization of both ends of the starting clutch, which will cause the engine load to increase rapidly, and may cause the vehicle engine to stall.

[0046] The following describes some vehicle operating conditions where turbine reversal may occur.

[0047] For example, when the vehicle is moving forward at a low speed, the driver switches the handle to the R gear. At this time, the vehicle will continue to move forward due to inertia and gradually slow down. As a result, the vehicle's driving direction does not match the position of the vehicle handle. Since the vehicle is moving forward, but the speed is gradually decreasing, the output shaft of the starting clutch still rotates forward during this process. Due to the action of the planetary gear, the speed of the input end of the starting clutch will form a certain speed ratio with the speed of the output end, and the direction of the speed changes until the speeds of both ends of the R gear clutch are synchronized. The actual vehicle phenomenon is that the speed of the input end of the starting clutch drops to 0 and then rises, and finally maintains a certain speed ratio relationship with the speed of the output end of the starting clutch. Among them, the clutch speed ratio relationship is determined by the clutch hardware structure. Under this working condition, when the vehicle is sliding forward and decelerating, the speed of the output end of the starting clutch is in a certain speed ratio relationship with the vehicle speed, and the speed ratio relationship is determined by the steel belt speed ratio and the main reduction ratio. Therefore, when the vehicle does not stop, the speed of the clutch output end does not drop to 0. After the engine torque switches the power transmission direction through the R gear clutch, it will act on the wheels to form a backward driving force, which together with the vehicle's rolling resistance / wind resistance, will prevent the vehicle from continuing to slide forward. Only after the vehicle stops can the engine drive the vehicle to move backward.

[0048] For another example, after the driver stops the car on a slope, he releases the brake and accelerator, moves the handle to the D gear, and the D gear clutch begins to engage gradually. However, the vehicle will slide backwards due to gravity. As a result, the vehicle's driving direction does not match the position of the vehicle's handle. As the torque of the D gear clutch gradually increases, the speed of the master / slave end of the starting clutch gradually synchronizes, but the speed direction of the active end of the starting clutch may still be reversed (for example, the vehicle slides backwards at this time, but the engine drive torque is not enough to overcome the effect of gravity). Under this sliding condition, due to the closure of the transmission chain of the transmission (because the D gear clutch is locked), the turbine may reverse, increasing the load on the engine and potentially posing a risk of flameout.

[0049] Another example is that when the vehicle is reversing, the driver shifts the steering wheel to the D gear, or the driver reverses uphill and the vehicle slips, resulting in a situation where the vehicle's driving direction does not match the position of the vehicle's steering wheel. Or, when the vehicle is moving forward on a low-adhesion road (such as snow), the steering wheel is turned sharply, causing the vehicle to slide backward, etc., resulting in a situation where the vehicle's driving direction does not match the position of the vehicle's steering wheel.

[0050] The operating conditions described above may cause the vehicle's turbine to reverse, which may cause the engine to stall and may potentially damage the transmission hardware.

[0051] Based on this, the embodiment of the present application first identifies whether there is a turbine reversal condition after the vehicle shifts gears, so as to timely predict the subsequent vehicle flameout risk. In addition, after the vehicle shifts gears, the start clutch is directly controlled to engage without delay, which can improve the speed of the vehicle's power response without lag.

[0052] In a possible implementation, the embodiment of the present application provides a specific implementation method for identifying whether there is a turbine reversal condition after a vehicle shifts gears, including:

[0053] According to the vehicle handle position, gearbox output shaft direction and turbine speed after the vehicle shifts gears, it is identified whether there is a turbine reversal condition after the vehicle shifts gears.

[0054] Among them, the vehicle handle position can reflect the driver's intention, and the vehicle handle position includes the R gear position and the D gear position. Among them, the direction of the gearbox output shaft is used to indicate the direction of vehicle travel. The gearbox output shaft direction includes three directions: Forward, Standstill and Reverse. When the gearbox output shaft direction is forward, the vehicle travels in the forward direction; when the output shaft direction is stop, the vehicle stops; when the output shaft direction is reverse, the vehicle travels in the reverse direction. The turbine speed is the current actual speed of the turbine, which can be collected by the corresponding sensor and is not limited here.

[0055] It is understandable that whether the WRD condition has occurred can be determined based on whether the vehicle handle position and the gearbox output shaft direction are consistent after the vehicle shifts. Furthermore, turbine reversal affects the turbine speed. Combining the vehicle handle position, gearbox output shaft direction and turbine speed after the vehicle shifts, it can be identified whether the turbine reversal condition has occurred after the vehicle shifts.

[0056] In specific implementation, according to the vehicle handle position, the gearbox output shaft direction and the turbine speed after the vehicle shifts gears, it is identified whether there is a turbine reversal condition after the vehicle shifts gears, including:

[0057] When the vehicle handle position after the vehicle shifts gears is different from the direction of the gearbox output shaft, the turbine speed crosses zero, and the turbine speed change rate has opposite signs before and after the turbine speed crosses zero, it is identified that the turbine reversal condition exists after the vehicle shifts gears.

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

[0059] "The turbine speed has a zero-crossing phenomenon" means that the turbine speed first decreases to 0 and then gradually increases. This also shows that the turbine speed change rate has opposite signs before and after the turbine speed passes through zero, that is, the turbine speed change rate before the turbine speed passes through zero is negative, indicating that the turbine speed is decreasing, and the turbine speed change rate after the turbine speed passes through zero is positive, indicating that the turbine speed is increasing. Usually, the torque converter works in the traction condition. When the starting clutch is not engaged, the turbine speed is affected by the engine torque and rotates forward at a speed close to the engine speed. When the starting clutch is in the process of engagement, the turbine may start to reverse under the action of a large torque. During this process, the turbine speed first rotates forward and decelerates, and then reverses after decelerating to 0. The speed gradually increases, and the final speed depends on the output speed of the starting clutch and the starting clutch speed ratio. Therefore, on the basis of determining the occurrence of the WRD condition, the turbine reversal condition can be identified by judging the "zero-crossing" phenomenon of the turbine speed and the positive and negative change rate of the turbine speed before and after the "zero-crossing".

[0060] S202: When a turbine reversal condition exists, estimate the risk of the vehicle stalling.

[0061] After the vehicle shifts gears, if there is a turbine reverse working condition, the vehicle is at risk of stalling. At this time, it is necessary to estimate the risk of the vehicle stalling. For example, real-time estimation can be performed to predict the possibility of vehicle stalling in real time, and then the vehicle can be controlled in advance to prevent the vehicle engine from stalling.

[0062] In the embodiment of the present application, after the vehicle shifts gears, the starting clutch is directly controlled to engage. There are two situations: the starting clutch engagement process and the starting clutch engagement completion. Since the vehicle engine may have the risk of flameout in both situations, the embodiment of the present application provides a method for estimating the flameout risk of the vehicle in the two situations of "during the starting clutch engagement process" and "after the starting clutch engagement completion".

[0063] In specific implementation, the specific implementation method for estimating the risk level of vehicle stalling includes A1-A2:

[0064] A1: During the engagement of the starting clutch, the estimated engine speed is calculated, and the risk of vehicle stalling is estimated based on the estimated engine speed, the target engine idle speed, and the current actual engine speed.

[0065] It is understandable that when the engine speed is lower than the engine idle speed, the risk of the vehicle stalling is higher. Therefore, in order to predict the risk of the vehicle stalling, it is necessary to first calculate the estimated engine speed, which is the estimated engine speed.

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

[0067] A11: 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.

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

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

[0070]

[0071] Among them, the engine speed change rate represents the change of the engine speed, the current actual engine speed can be collected by the sensor, the estimated engine speed is the predicted value, and the estimated clutch speed synchronization time is the time required for the starting clutch input speed to synchronize with the output speed. Among them, the starting clutch input speed is the same as the turbine speed.

[0072] It is understandable that the estimated engine speed is the estimated engine speed when the clutch speed is synchronized, which is a predicted quantity. On the basis of confirming that the turbine reversal condition occurs, the vehicle engine is prone to stall when the clutch speed is synchronized, so the embodiment of the present application estimates the degree of stall risk of the vehicle based on the estimated engine speed when the clutch speed is synchronized.

[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 impeller moment of inertia;

[0075] Among them, the engine load torque is calculated by 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.

[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 present application provides a calculation formula for the engine speed change rate, as follows:

[0078]

[0079]

[0080] Among them, T e is the engine output torque, which can be obtained from the actual vehicle Can network signal and is related to the accelerator pedal position (which can reflect the driver's intention); 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 speed of the engine, which can be obtained from the actual vehicle Can network signal; dω e / dt is the rate of change of engine speed; ω Turb is the torque converter turbine shaft speed (i.e., turbine speed), which can be obtained from the transmission speed sensor signal; the engine load torque includes the transmission oil pump load torque and the torque converter hydraulic load torque, T TransLoad is the engine load torque, then T TransLoad =T OilPumpLoad +Cω e 2 , T OilPumpLoadis the gearbox oil pump load torque, which can be obtained through bench testing and is related to factors such as the gearbox oil temperature. e 2 is the hydraulic load torque of the torque converter, which is obtained by the capacity coefficient of the torque converter and the current actual speed of the engine. T is the transmission oil temperature, and f1 is the first functional relationship.

[0081] C is the capacity coefficient of the torque converter, which is a hydraulic characteristic parameter of the torque converter and can be obtained through bench tests. It is related to the transmission oil temperature and the torque converter speed ratio and has a first function relationship. Figure 3 , Figure 3 The following is a schematic diagram of the change of the bench test value of the capacity coefficient under the turbine reverse working condition provided in the embodiment of the present application. Under the turbine reverse working condition, the bench test value of the capacity coefficient of the torque converter is as follows: Figure 3 As shown in the figure. When the turbine is reversed, the C coefficient increases with the increase of the torque converter speed ratio (the ratio of the turbine speed to the current actual engine speed). When the speed ratio exceeds 1.3, the C coefficient increases sharply, that is, the greater the turbine reverse speed and the more it exceeds the engine speed, the greater the hydraulic load torque of the gearbox on the engine.

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

[0083] A112: Calculates the turbine speed change rate based on the turbine output torque, the clutch torque capacity, the turbine shaft moment of inertia, and the clutch input moment of inertia.

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

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

[0086]

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

[0088] As an optional example, the turbine end output torque is calculated by the torque converter capacity coefficient, the torque converter torque ratio coefficient, the current actual engine speed and the torque capacity of the torque converter lockup clutch; the torque capacity of the torque converter lockup clutch is zero during the engagement process of the vehicle's starting clutch; the torque converter torque ratio coefficient and the torque converter speed ratio have a second functional relationship f2.

[0089] Turbine end output torque T Turb The size of is related to the hydraulic characteristics of the torque converter and the locking capacity of the torque converter. For example, the turbine end output torque T Turb The calculation formula is as follows:

[0090] T Turb =K×C×ω e 2 +T TCC

[0091]

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

[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 torque capacity of the clutch is T Clch The calculation formula is as follows:

[0095]

[0096] Among them, T Clch is the torque capacity of the clutch; μ is the friction coefficient of the clutch friction plate, which is a clutch hardware parameter; p is the pressure acting on the friction plate; n is the number of clutch friction pairs, which is a clutch hardware parameter; A is the effective friction area of ​​the clutch friction plate, which is a clutch hardware parameter; R1 is the inner diameter of the clutch friction plate, which is a clutch hardware parameter; R2 is the outer diameter of the clutch friction plate, which is a clutch hardware parameter.

[0097] A113: Calculates the estimated clutch speed synchronization time based on the turbine speed change rate, turbine speed, and clutch output speed.

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

[0099]

[0100] Among them, t Engd To estimate the clutch speed synchronization time; Turb is the turbine speed; ω ClchOtpt is the clutch output speed. Based on this formula, the estimated clutch speed synchronization time can be calculated.

[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 estimated engine speed can be calculated by A11 and A12. It can be understood that since the estimated engine speed ω is calculated eCalc , then the turbine speed in the first functional relationship and the second functional relationship formula needs to be replaced with the turbine estimated speed. The turbine estimated speed is obtained from the turbine speed and the turbine speed change rate.

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

[0103]

[0104] Based on this, the estimated engine speed ω can be obtained eCalc The calculation formula is as follows:

[0105]

[0106] From this formula, we can know that the turbine speed ω Turb 、Clutch output speedω ClchOtpt , engine speedω e , clutch pressure p and other information, and estimate the engine speed ω when the clutch speed is synchronized eCalc .

[0107] After the estimated engine speed is calculated based on A11-A12, the embodiment of the present application provides a specific implementation method for estimating the risk of vehicle stalling according to the estimated engine speed, the target engine idle speed and the current actual engine speed, including:

[0108] 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, the estimated vehicle stall risk level meets the preset conditions.

[0109] That is, the estimated engine speed ω ecalc Compared with the target idle speed of the engine, the lower the estimated engine speed is than the target idle speed, the higher the risk of engine stalling is, and it can be considered that the risk of stalling of the vehicle meets the preset conditions. In addition, if the current actual engine speed is lower than the target idle speed of the engine, it is also identified as a high risk of engine stalling, and it can be considered that the risk of stalling of the vehicle meets the preset conditions. Based on this, the engine stalling risk coefficient λ can be set, and its calculation formula is as follows:

[0110]

[0111] Among them, λ is the engine flameout risk coefficient. The lower the engine flameout risk coefficient, the greater the flameout risk; ω Idl It is the target idle speed of the engine, which can be obtained from the vehicle CAN network signal.

[0112] A2: After the starting clutch is engaged, estimate the risk of the vehicle stalling based on the current actual engine speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed and engine load torque.

[0113] After the start clutch is engaged, the vehicle engine still has a risk of stalling. In one optional manner, the vehicle's stalling risk may be estimated based on the current actual engine speed and the engine speed change rate. In another optional manner, the vehicle's stalling risk may also be estimated based on the turbine speed, turbine rotation direction, vehicle speed, and engine load torque.

[0114] Based on this, the embodiment of the present application provides a specific implementation method for estimating the risk of vehicle stalling according to the current actual engine speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed and engine load torque, including:

[0115] 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, it is estimated that the vehicle's flameout risk level meets the preset conditions;

[0116] or,

[0117] When it is identified based on the turbine speed that the turbine rotation direction is turbine reverse, the engine load torque is greater than the torque threshold and the vehicle speed is greater than the vehicle speed threshold, it is estimated that the vehicle's stall risk level meets the preset conditions.

[0118] Among them, the specific implementation method of "estimating the vehicle's stall risk level based on the current actual engine speed and the engine speed change rate" is: 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 vehicle stall risk level meets the preset conditions.

[0119] Specifically, the degree of flameout risk of the vehicle can be estimated based on the current actual speed of the engine and the target idle speed of the engine. It can be seen that the flameout risk of the vehicle engine after the start clutch is engaged is lower than the flameout risk of the vehicle engine during the engagement of the start clutch. In order to make the flameout risk estimate of the vehicle after the start clutch is engaged more accurate, a speed threshold can be set, the speed threshold is a negative value, and the sum of the engine target idle speed and the speed threshold is calculated. Then, the current actual speed of the engine is compared with the sum value, and when the current actual speed of the engine is less than or equal to the sum value, it can be determined that the flameout risk of the vehicle is high. In addition, when the engine speed change rate is negative, it means that the engine speed is still continuing to decrease on the basis of being lower than the target idle speed of the engine. At this time, it is determined that the flameout risk degree of the vehicle meets the preset conditions, that is, the risk of the vehicle engine being flameout is high, and vehicle control is required.

[0120] In addition, the specific implementation method of "estimating the vehicle's stall risk level based on turbine speed, turbine rotation direction, vehicle speed and engine load torque" is: when it is identified according to the turbine speed that the turbine rotation direction is turbine reverse, the engine load torque is greater than the torque threshold and the vehicle speed is greater than the vehicle speed threshold, the estimated vehicle stall risk level meets the preset conditions.

[0121] Specifically, the direction of turbine rotation can be identified based on the turbine speed. If the turbine is reversed, the vehicle engine may stall. On this basis, a torque threshold (a positive value) and a vehicle speed threshold are set. When the engine load torque is greater than the torque threshold and the vehicle speed is greater than the vehicle speed threshold, it is determined that the vehicle's stall risk meets the preset conditions. It can be understood that when the engine load torque is greater than the torque threshold, it means that the engine capacity is insufficient to overcome the turbine reversal, and the vehicle's stall risk is high. In addition, in the above case, the higher the vehicle speed, the easier it is for the vehicle engine to stall.

[0122] S203: When the risk level of the vehicle stalling meets a preset condition, the target oil pressure of the starting clutch is controlled to be reduced to open the starting clutch to prevent the vehicle engine from stalling.

[0123] When the vehicle's stall risk level meets the preset conditions, it indicates that the risk of engine stall is relatively high. At this time, the starting clutch target oil pressure is controlled to decrease rapidly to quickly open the clutch, cut off power transmission, and prevent the vehicle's engine from stalling.

[0124] In a possible implementation, the embodiment of the present application provides a specific implementation method of controlling and reducing the target oil pressure of the starting clutch, including:

[0125] The target oil pressure of the vehicle's starting clutch is controlled to step to a range near the clutch half-engagement point.

[0126] It is understandable that when the risk of engine stalling is detected to be high, the starting clutch target oil pressure is stepped to near the clutch half-engagement point. In this way, on the one hand, the clutch torque capacity is reduced by reducing the clutch oil pressure, thereby alleviating the degree of turbine reversal. On the other hand, the clutch target oil pressure is maintained near the half-engagement point, and no pre-charging is required when the clutch is re-locked next time, thereby improving the clutch oil pressure response, quickly completing the clutch engagement, and restoring power transmission.

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

[0128] Based on the above S201-S203 related contents, it can be known that the present 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 WRD working condition occurs during the vehicle shift, the turbine may be reversed, causing the engine load to increase, thereby causing the engine to stall. Based on this, the present application first identifies whether there is a turbine reversal working condition after the vehicle shifts. At the same time, regardless of whether the WRD working condition occurs, the starting clutch is controlled to engage after the vehicle shifts to increase the speed of the vehicle's power response. Furthermore, when it is confirmed that there is a turbine reversal working condition, the degree of stall risk of the vehicle is estimated. When the degree of stall risk of the vehicle meets the preset conditions, it indicates that the degree of stall risk of the vehicle 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, and alleviate the turbine reversal phenomenon, thereby reducing the engine load torque and preventing the vehicle engine from stalling. In this way, the present application also prevents the vehicle engine from stalling by identifying the turbine reversal condition and predicting the risk of engine stalling, reducing the oil pressure in time when the risk of engine stalling is high, and controlling the starting clutch to open.

[0129] See also Figure 4 , Figure 4 A flow chart of another vehicle engine anti-stall control method provided in an embodiment of the present application. Figure 4As shown, in the embodiment of the present application, the turbine reversal condition is first identified, and if the turbine reversal condition occurs, the engine stall risk is predicted. Otherwise, the clutch oil pressure is controlled to rise to complete the engagement. If the engine stall risk is high (indicating that the preset conditions are met), the clutch oil pressure is controlled at the semi-engagement point, otherwise the turbine reversal condition is continuously identified. If the stall risk becomes lower, the clutch oil pressure is controlled to rise to complete the engagement. If the stall risk is still high, the clutch oil pressure continues to be controlled to maintain the semi-engagement oil pressure, and the engine stall risk is continuously predicted at the same time.

[0130] See also Figure 5a , Figure 5a A schematic diagram of a WRD control strategy provided in an embodiment of the present application. Figure 5a As shown in the figure, during the vehicle shifting process, the accelerator and brake are released, if the lever position is changed from D gear to R gear (intermediate N gear transition), and the transmission output shaft speed direction continues to be Forward, then the WRD condition occurs. In the WRD control strategy of the related art, when the WRD condition occurs, the starting clutch is immediately controlled to delay for a certain period of time before starting to engage, which is reflected in Figure 5a In the middle, the target oil pressure of the starting clutch is supplied after a period of time. Figure 5a It can be seen that after the start clutch is engaged, the turbine reversal condition still occurs, but the occurrence of the turbine reversal condition is delayed. When the engine speed is low, the start clutch is controlled to open, the engine is turned off, the transmission output shaft speed direction is Standstill, and the vehicle stops. After the vehicle stops, the engine can drive the vehicle to move backward. It can be seen that Figure 5a The control strategy shown not only makes the vehicle control have a certain hysteresis, but also still cannot avoid the vehicle engine stalling.

[0131] See also Figure 5b , Figure 5b A schematic diagram of an anti-stall control strategy provided in an embodiment of the present application. Figure 5b As shown, during the vehicle shifting process, release the accelerator and brake, if the handle position is changed from D gear to R gear (intermediate N gear transition), and the transmission output shaft speed direction continues to be Forward, the WRD condition will occur. At this time, in the vehicle engine anti-stall control method provided in the embodiment of the present application, if the WRD condition occurs, the clutch target oil pressure is still supplied, and the turbine reversal condition is identified. When the turbine reversal condition occurs, the engine stall risk is predicted based on the estimated engine speed. When the risk of engine stall is high, the clutch target oil pressure is controlled at the half-engagement point to alleviate the turbine reversal condition. When the risk of engine stall is low or the driver steps on the accelerator pedal, the clutch is reengaged to complete the reverse driving of the vehicle. It can be seen that Figure 5bThe vehicle engine anti-stall control method provided in the embodiment of the present application not only makes the vehicle control response speed faster, but also avoids the vehicle engine stalling as much as possible.

[0132] Based on a vehicle engine anti-stall control method provided by the above method embodiment, the embodiment of the present application also provides a vehicle engine anti-stall control device, and the vehicle engine anti-stall control device will be described below in conjunction with the accompanying drawings.

[0133] See also Figure 6 As shown in FIG. 1 , this figure is a schematic diagram of the structure of a vehicle engine anti-stall control device provided by an embodiment of the present application. The vehicle includes an automatic transmission, the automatic transmission includes a hydraulic torque converter and a starting clutch, the hydraulic torque converter includes a turbine, such as Figure 6 As shown, the vehicle engine flameout prevention control device comprises:

[0134] an identification unit 601, for identifying whether a turbine reversal condition exists after the vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears;

[0135] An estimating unit 602, configured to estimate the risk of flameout of the vehicle when the turbine reverse working condition exists;

[0136] The control unit 603 is used to control the reduction of the target oil pressure of the starting clutch to open the starting clutch to prevent the vehicle engine from stalling when the stall risk level of the vehicle meets a preset condition.

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

[0138] The identification subunit is used to identify whether there is a turbine reversal condition after the vehicle shifts gears according to the vehicle handle position, the gearbox output shaft direction and the turbine speed after the vehicle shifts gears.

[0139] In a possible implementation, the identification subunit is specifically used to:

[0140] When the position of the vehicle handle after the vehicle shifts gears is different from the direction of the gearbox output shaft, the turbine speed crosses zero, and the turbine speed change rate has opposite signs before and after the turbine speed crosses zero, it is recognized that the turbine reversal condition exists after the vehicle shifts gears.

[0141] In a possible implementation, the estimating unit 602 includes:

[0142] a first calculation subunit, configured to calculate an estimated engine speed during the engagement process of the starting clutch, and estimate a flameout risk degree of the vehicle according to the estimated engine speed, an engine target idle speed, and a current actual engine speed;

[0143] The estimation subunit is used to estimate the risk of stalling of the vehicle according to the current actual engine speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed and engine load torque after the starting clutch is engaged.

[0144] In a possible implementation manner, the first computing subunit is specifically configured to:

[0145] 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, it is estimated that the flameout risk level of the vehicle meets a preset condition;

[0146] The estimation subunit is specifically used for:

[0147] When the current actual speed of the engine is less than or equal to the sum of the target idle speed of the engine and the speed threshold and the engine speed change rate is negative, it is estimated that the flameout risk level of the vehicle meets a preset condition;

[0148] or,

[0149] When it is identified based on the turbine speed that the turbine rotation direction is turbine reverse, the engine load torque is greater than a torque threshold, and the vehicle speed is greater than a vehicle speed threshold, it is estimated that the flameout risk level of the vehicle meets preset conditions.

[0150] In a possible implementation, the first computing subunit includes:

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

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

[0153] The second computing subunit further includes:

[0154] a third calculation subunit, for calculating the engine speed change rate based on the engine output torque, the engine load torque, the engine rotational inertia, and the pump impeller rotational inertia;

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

[0156] The second computing subunit comprises:

[0157] a fourth calculation subunit, for calculating a turbine speed change rate based on the turbine end output torque, the torque capacity of the clutch, the turbine shaft rotational inertia, and the clutch input end rotational inertia;

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

[0159] The turbine end output torque is calculated by the torque converter capacity coefficient, the torque converter torque ratio coefficient, the current actual engine speed and the torque converter lockup clutch torque capacity; the torque converter lockup clutch torque capacity is zero during the engagement process of the vehicle's starting clutch; the torque converter torque ratio coefficient and the torque converter speed ratio have a second functional relationship;

[0160] The torque capacity of the clutch is calculated based on 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.

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

[0162] The target oil pressure of the starting clutch of the vehicle is controlled to step to a range near the clutch half-engagement point.

[0163] It should be noted that the specific implementation of each unit in this embodiment can refer to the relevant description in the above method embodiment. The division of units in the embodiment of the present application is schematic and is only a logical function division. There may be other division methods in actual implementation. The functional units in the embodiment of the present application can be integrated in a processing unit, or each unit can exist physically separately, 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 different units. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0164] An embodiment of the present application further provides a computer-readable medium having a computer program stored thereon, wherein when the program is executed by a processor, the vehicle engine anti-stall control method as described above is implemented.

[0165] See also Figure 7 , Figure 7 A schematic diagram illustrating an electronic device according to an exemplary embodiment of the present disclosure.

[0166] Reference Figure 7 According to an exemplary embodiment of the present disclosure, an electronic device includes a storage device 71 and one or more processors 72. The storage device 71 stores one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement any of the above-mentioned vehicle engine anti-stall control methods. The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a starting clutch, and the torque converter includes a turbine.

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

[0168] identifying whether a turbine reversal condition exists after a vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears;

[0169] When the turbine reverse working condition exists, estimating the risk of flameout of the vehicle;

[0170] When the flameout risk level of the vehicle meets a preset condition, the target oil pressure of the starting clutch is controlled to be reduced to open the starting clutch to prevent the vehicle engine from flameout.

[0171] It can be known from the description of the above implementation mode that those skilled in the art can clearly understand that all or part of the steps in the above-mentioned embodiment method can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product can be stored in a storage medium such as ROM / RAM, a disk, an optical disk, etc., including several instructions for enabling a computer device (which can be a personal computer, a server, or a network communication device such as a media gateway, etc.) to execute the methods described in the various embodiments of the present application or certain parts of the embodiments.

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

[0173] It should also be noted that, in this article, the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0174] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vehicle engine flameout prevention control method, characterized in that: The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a launch clutch, the torque converter includes a turbine, and the method includes: identifying whether a turbine reversal condition exists after a vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears; When the turbine reverse working condition exists, estimating the risk of flameout of the vehicle; When the flameout risk level of the vehicle meets a preset condition, the target oil pressure of the starting clutch is controlled to be reduced to open the starting clutch to prevent the vehicle engine from flameout.

2. The method according to claim 1, characterized in that The identifying whether there is a turbine reverse working condition after the vehicle shifts gears includes: According to the vehicle handle position, gearbox output shaft direction and turbine speed after the vehicle shifts gears, it is identified whether there is a turbine reversal condition after the vehicle shifts gears.

3. The method according to claim 2, characterized in that The method of identifying whether there is a turbine reversal condition after the vehicle shifts gears according to the vehicle handle position, the gearbox output shaft direction and the turbine speed after the vehicle shifts gears comprises: When the position of the vehicle handle after the vehicle shifts gears is different from the direction of the gearbox output shaft, the turbine speed crosses zero, and the turbine speed change rate has opposite signs before and after the turbine speed crosses zero, it is recognized that the turbine reversal condition exists after the vehicle shifts gears.

4. The method according to claim 1, characterized in that: The estimating the risk level of the vehicle stalling includes: During the engagement of the starting clutch, an estimated engine speed is calculated, and a flameout risk of the vehicle is estimated based on the estimated engine speed, an engine target idle speed, and a current actual engine speed; After the starting clutch is engaged, the flameout risk of the vehicle is estimated based on the current actual engine speed, engine speed change rate, turbine speed, turbine rotation direction, vehicle speed, and engine load torque.

5. The method according to claim 4, characterized in that The estimating the flameout risk of the vehicle according to the estimated engine speed, the target engine idle speed and the current actual engine speed includes: 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, it is estimated that the flameout risk level of the vehicle meets a preset condition; The estimating the flameout risk of the vehicle according to the current actual engine speed, the engine speed change rate, the turbine speed, the turbine rotation direction, the vehicle speed and the engine load torque includes: When the current actual speed of the engine is less than or equal to the sum of the target idle speed of the engine and the speed threshold and the engine speed change rate is negative, it is estimated that the flameout risk level of the vehicle meets a preset condition; or, When it is identified based on the turbine speed that the turbine rotation direction is turbine reverse, the engine load torque is greater than a torque threshold, and the vehicle speed is greater than a vehicle speed threshold, it is estimated that the flameout risk level of the vehicle meets preset conditions.

6. The method according to claim 4, characterized in that The calculating of the estimated engine speed includes: Calculating an engine speed change rate and an estimated clutch speed synchronization time, and calculating a product of the engine speed change rate and the estimated clutch speed synchronization time; Determine the sum of the current actual speed of the engine and the product as the estimated speed of the engine; The calculating the engine speed change rate comprises: Calculating the engine speed change rate based on the engine output torque, the engine load torque, the engine rotational inertia, and the pump impeller rotational inertia; The engine load torque is calculated by the gearbox oil pump load torque, the torque converter capacity coefficient and the current actual speed of the engine; the torque converter capacity coefficient has a first functional relationship with the torque converter speed ratio and the gearbox oil temperature, and the torque converter speed ratio is the ratio of the turbine speed to the current actual speed of the engine; The calculating and estimating the clutch speed synchronization time includes: Calculate the turbine speed change rate based on the turbine end output torque, the clutch torque capacity, the turbine shaft rotational inertia, and the clutch input end rotational inertia; Calculating an estimated clutch speed synchronization time based on the turbine speed change rate, the turbine speed, and the clutch output end speed; The turbine end output torque is calculated by the torque converter capacity coefficient, the torque converter torque ratio coefficient, the current actual engine speed and the torque converter lockup clutch torque capacity; the torque converter lockup clutch torque capacity is zero during the engagement process of the vehicle's starting clutch; the torque converter torque ratio coefficient and the torque converter speed ratio have a second functional relationship; The torque capacity of the clutch is calculated based on 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 controlling lowers the target oil pressure of the starting clutch, including: The target oil pressure of the starting clutch of the vehicle is controlled to step to a range near the clutch half-engagement point.

8. A vehicle engine flameout prevention control device, characterized in that: The vehicle includes an automatic transmission, the automatic transmission includes a torque converter and a start clutch, the torque converter includes a turbine, and the device includes: an identification unit, used for identifying whether a turbine reversal condition exists after the vehicle shifts gears, and controlling the start clutch to engage after the vehicle shifts gears; an estimating unit, configured to estimate a flameout risk level of the vehicle when the turbine reverse working condition exists; The control unit is used for controlling the reduction of the target oil pressure of the starting clutch to open the starting clutch to prevent the vehicle engine from stalling when the risk level of the vehicle stalling meets a preset condition.

9. An electronic device, characterized in that: include: one or more processors; a storage device having one or more programs stored thereon, When the one or more programs are executed by the one or more processors, the one or more processors implement the vehicle engine anti-stall control method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: A computer program is stored thereon, wherein when the computer program is executed by a processor, the vehicle engine anti-stall control method as described in any one of claims 1-7 is implemented.

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