Control method and device for vehicle to start smoothly, and vehicle

Abstract

The application discloses a control method and device for smooth starting of a vehicle and the vehicle. The control method comprises the following steps: acquiring starting information of the vehicle; determining whether the vehicle meets low-temperature starting conditions according to the starting information; when it is determined that the vehicle meets the low-temperature starting conditions, determining a torque limiting value of an engine according to an actual torque of the engine, a first torque compensation value determined by a temperature value of a transmission of the vehicle and a second torque compensation value determined by an opening degree of a throttle of the vehicle and the temperature value of the transmission at a current time; and controlling a torque output by the engine according to the torque limiting value of the engine. In the low-temperature conditions, the torque limiting value of the engine is taken as a maximum value of the torque output by the engine, the torque output by the engine is limited in the torque limiting value, and a torque change rate of the engine is reduced. The response time of a clutch is prolonged, so that the clutch can follow the change rate of the engine, and smooth starting of the vehicle is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile technology, in particular to a vehicle smooth starting control method and device and vehicle. BACKGROUND

[0002] The vehicle includes a transmission and a clutch. During the starting process of the vehicle, the torque of the engine is smoothly transmitted to the gear of the transmission through the clutch. Through the action of the gear inside the transmission, the torque of the engine is finally applied to the driving wheel of the vehicle, realizing the smooth starting process of the vehicle.

[0003] However, in the actual starting process of the vehicle, the torque output rate of the engine will be too fast or too slow due to changes in external conditions, which puts high requirements on the system, such as good followability of the clutch pressure, linear torque transmission control process of the clutch, and linear transmission of the engine torque by the transmission. However, the transmission usually uses a hydraulic system as a power transmission component. Under low temperature conditions, the pressure response of the hydraulic system is relatively slow, which causes the transmission to fail to follow the torque change of the engine when the torque of the engine changes too fast, resulting in an increase in the engine speed and the occurrence of the vehicle jolt phenomenon, which is not good for the driver's experience. SUMMARY

[0004] The present application provides a vehicle smooth starting control method and device and vehicle to control the smooth starting of the vehicle under low temperature conditions and improve the user experience.

[0005] According to an aspect of the present application, a vehicle smooth starting control method is provided, comprising:

[0006] obtaining starting information of the vehicle;

[0007] determining whether the vehicle meets low temperature starting conditions according to the starting information;

[0008] when it is determined that the vehicle meets the low temperature starting conditions, determining a torque limit value of the engine at the current time according to the actual torque of the engine, a first torque compensation value determined by the temperature value of the transmission of the vehicle, and a second torque compensation value determined by the opening degree of the accelerator of the vehicle and the temperature value of the transmission;

[0009] controlling the torque output by the engine according to the torque limit value of the engine, so that the torque output by the engine is less than or equal to the torque limit value.

[0010] Optionally, the low-temperature starting condition at least comprises: the temperature of the transmission is greater than or equal to a first temperature threshold and less than or equal to a second temperature threshold, the actual speed of the clutch is less than or equal to a clutch speed threshold corresponding to the opening degree of the accelerator at the current time, the vehicle meets a starting control preset condition, and the current gear of the transmission is less than a starting gear threshold.

[0011] The starting control preset condition is that a difference between an absolute value of a first deviation and an absolute value of a second deviation is greater than a set speed threshold, wherein the first deviation is a difference between the actual speed of the engine and the actual speed of the clutch at the current time, and the second deviation is a difference between the actual speed of the clutch and the target speed of the engine at the current time.

[0012] Optionally, the low-temperature starting condition further comprises: the opening degree of the accelerator is greater than a first accelerator threshold, the speed of the vehicle is greater than or equal to a first speed threshold and less than or equal to a second speed threshold, and the actual torque of the engine is greater than a set torque threshold.

[0013] Optionally, after the torque output by the engine is controlled according to the torque limit value of the engine, the method further comprises:

[0014] acquiring the pressure of the clutch of the vehicle or the speed of the vehicle;

[0015] determining whether the clutch meets a following condition according to the pressure of the clutch or the speed of the vehicle;

[0016] when the clutch meets the following condition, determining the torque output by the engine according to the torque limit value of the engine at a previous time when the clutch meets the following condition and a torque change rate step value set according to the temperature of the transmission.

[0017] Optionally, the following condition comprises: the pressure of the clutch is greater than a set pressure threshold, or the speed of the vehicle is greater than or equal to a third speed threshold; wherein the third speed threshold is greater than the second speed threshold.

[0018] Optionally, when the clutch meets the following condition, determining the torque output by the engine according to the torque limit value of the engine at a previous time when the clutch meets the following condition and a torque change rate step value set according to the temperature of the transmission, comprises:

[0019] the torque M output by the engine meets the formula:

[0020] M=M0+kt, wherein M0 is the torque limit value of the engine at a previous time when the clutch meets the following condition, k is the torque change rate step value, and t is time.

[0021] Optionally, after the torque limit value of the engine at the previous time point when the clutch of the vehicle meets the follow condition and the torque change rate step set according to the temperature of the transmission are determined, comprising:

[0022] The actual torque of the engine, the expected torque of the engine and the speed of the vehicle are obtained;

[0023] It is determined whether the vehicle meets the torque limit exit condition according to the actual torque of the engine, the expected torque of the engine and the speed of the vehicle;

[0024] When the engine meets the torque limit exit condition, the engine is controlled to output torque according to the opening degree of the throttle.

[0025] Optionally, the torque limit exit condition includes: the absolute value of the difference between the actual torque of the engine and the expected torque of the engine is less than a set torque deviation threshold, or the speed of the vehicle is less than the first speed threshold.

[0026] According to another aspect of the present application, there is provided a vehicle smooth starting control device, comprising:

[0027] A starting information acquisition module is configured to acquire starting information of a vehicle;

[0028] A starting determination module is configured to determine whether the vehicle meets a low-temperature starting condition according to the starting information;

[0029] A torque limit value determination module is configured to, when it is determined that the vehicle meets the low-temperature starting condition, determine a torque limit value of an engine of the vehicle at a current time point according to the actual torque of the engine, a first torque compensation value determined by a temperature value of a transmission of the vehicle and a second torque compensation value determined by an opening degree of a throttle of the vehicle and the temperature value of the transmission;

[0030] An output module is configured to control torque output by the engine according to the torque limit value of the engine, so that the torque output by the engine is less than or equal to the torque limit value.

[0031] According to another aspect of the present application, there is provided a vehicle comprising the above-mentioned vehicle smooth starting control device.

[0032] The control method for vehicle smooth starting provided by the embodiment of the present application comprises: obtaining starting information of the vehicle; determining whether the vehicle meets low-temperature starting conditions according to the starting information; when it is determined that the vehicle meets the low-temperature starting conditions, determining a torque limiting value of an engine of the vehicle according to an actual torque of the engine, a first torque compensation value determined by a temperature value of a transmission of the vehicle, and a second torque compensation value determined by an opening degree of an accelerator of the vehicle and the temperature value of the transmission; and controlling a torque output by the engine according to the torque limiting value of the engine, so that the torque output by the engine is less than or equal to the torque limiting value. In the low-temperature conditions, when the vehicle meets certain conditions, the torque limiting value of the engine is generated according to the actual torque of the vehicle, the first torque compensation value, and the second torque compensation value, the torque limiting value of the engine is taken as the maximum value of the torque output by the engine, the torque output by the engine is limited within the torque limiting value, and the torque change rate of the engine is reduced. Then, the response time of the clutch is prolonged, so that the clutch can follow the change rate of the engine, and the vehicle can start smoothly.

[0033] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0035] Figure 1 is a flow chart of a control method for vehicle smooth starting provided by the embodiment of the present application;

[0036] Figure 2 is a structural schematic diagram of a vehicle provided by the embodiment of the present application;

[0037] Figure 3 is a flow chart of another control method for vehicle smooth starting provided by the embodiment of the present application;

[0038] Figure 4 is a working curve diagram of a vehicle in a low-temperature starting process provided by the embodiment of the present application;

[0039] Figure 5 is a flow chart of another control method for vehicle smooth starting provided by the embodiment of the present application;

[0040] Figure 6is a structural schematic view of a vehicle smooth starting control device provided by the embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0042] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0043] Figure 1 A flowchart of a vehicle smooth starting control method provided by the embodiment of the present application, the embodiment can be applicable to the case of controlling the vehicle to start smoothly at low temperature, the method can be executed by a vehicle smooth starting control device, the vehicle smooth starting control device can be realized in the form of hardware and / or software, and the vehicle smooth starting control device can be configured in the vehicle. Figure 2 A structural schematic view of a vehicle provided by the embodiment of the present application is shown in Figure 2 The vehicle includes an engine 1, a transmission 2, a clutch 3, a driving control unit 4 and a transmission control unit 5, the engine 1 is connected through the clutch 3 and the transmission 2, the driving control unit 4 is connected with the engine 1, for torque or speed control of the engine 1, the transmission control unit 5 is connected with the clutch 3 and the transmission 2 respectively, for gear control of the transmission 2, and controls whether the torque output by the engine 1 is transmitted to the inside of the transmission 2 through the control of the clutch 3. The driving control unit 4 and the transmission control unit 5 are electrically connected to transmit information. The transmission control unit 5 is also used to control the pressure of the clutch 3, to further determine the size of the torque transmitted by the engine. The following vehicle smooth starting control method is executed by the transmission control unit 5.

[0044] ReferenceFigure 1 and Figure 2 The control method of the vehicle smooth starting includes:

[0045] S110: Obtain the starting information of the vehicle.

[0046] For example, the starting information of the vehicle at least includes the temperature of the transmission, the current gear of the transmission, the actual speed of the engine, the actual speed of the clutch, the opening degree of the throttle and the target speed of the engine. Among them, the temperature of the transmission, the current gear of the transmission and the actual speed of the clutch are obtained by the transmission control unit 5 through different function sensors, which can be temperature sensor, gear sensor and speed sensor. The actual speed of the engine can be obtained by the driving control unit 4 and transmitted to the transmission control unit 5. The target speed of the engine and the opening degree of the throttle are directly determined by the transmission control unit 5. The target speed of the engine can be set according to the opening degree of the throttle. One throttle opening degree corresponds to one target speed of the engine. The corresponding relationship is set according to user demand, which is not limited here.

[0047] S120: Determine whether the vehicle meets the low-temperature starting condition according to the starting information.

[0048] The low-temperature starting condition at least includes that the temperature of the transmission is greater than or equal to the first temperature threshold and less than or equal to the second temperature threshold. The first temperature threshold and the second temperature threshold can be set according to user demand, for example, the first temperature threshold is-40℃ and the second temperature threshold is 10℃. Because the response of the transmission is slower when the temperature is lower, which is the main factor that causes the vehicle to start smoothly. Therefore, the low-temperature starting condition at least includes the limitation of the temperature of the transmission. When the temperature of the transmission is low, the torque limiting control of the engine is triggered to solve the problem of unstable vehicle starting at low temperature.

[0049] S130: When it is determined that the vehicle meets the low-temperature starting condition, at the current time, the torque limiting value of the engine is determined according to the actual torque of the engine of the vehicle, the first torque compensation value determined by the temperature value of the transmission of the vehicle and the second torque compensation value determined by the opening degree of the throttle of the vehicle and the temperature value of the transmission.

[0050] The transmission control unit 5 acquires the actual torque of the engine through the driving control unit 4. The first torque compensation value is determined according to the temperature value of the transmission, specifically, the temperature value of the transmission and the first torque compensation value are one-to-one corresponding, for example, when the temperature value of the transmission is -40℃, the first torque compensation value is 20Nm, when the temperature of the transmission is -20℃, the first torque compensation value is 30Nm. The second torque compensation value is determined by the opening degree of the vehicle's throttle and the temperature value of the transmission, specifically, the opening degree of the throttle and the temperature value of the transmission determine a unique second torque compensation value, for example, when the opening degree of the throttle is 5% and the temperature value of the transmission is -40℃, the second torque compensation value is 1Nm, when the opening degree of the throttle is 10% and the temperature value of the transmission is -20℃, the second torque compensation value is 2Nm. The torque limit value of the engine is less than or equal to the sum of the actual torque of the engine, the first torque compensation value and the second torque compensation value.

[0051] S140: Control the torque output by the engine according to the torque limit value of the engine, so that the torque output by the engine is less than or equal to the torque limit value.

[0052] Generally, the size of the torque output by the engine is determined by the opening degree of the throttle. In this embodiment, when it is determined that the vehicle meets the low-temperature starting condition, the control process of the torque of the engine is triggered, that is, the torque output by the engine is less than or equal to the torque limit value. That is, the torque limit value of the engine is determined through S130, the transmission control unit 5 controls the torque output by the engine to be less than or equal to the torque limit value through the driving control unit 4, thereby reducing the torque change rate of the engine.

[0053] Specifically, at low temperature, when the opening degree of the throttle is large, such as 70%, the torque of the engine changes quickly, the engine 1 changes from 0Nm to 200Nm within 0.5S, the clutch 3 responds slowly at low temperature and cannot follow the change of the engine 100%, resulting in that the torque transmitted to the transmission 2 is 150Nm at 0.5S, and the excess 50Nm will cause the speed of the engine 1 to rise. After the speed of the engine rises, the difference between the speed of the engine and the speed of the clutch increases, and after the clutch meets the following condition, the following condition can be referred to in the subsequent S161, the pressure of the clutch will immediately increase, causing the speed of the engine and the speed of the clutch to decrease to 0rpm within a short time, thereby causing the vehicle to appear to be unstable and causing the vehicle to start unevenly. In this embodiment, the torque output by the engine is limited within the torque limit value, the change process of the engine torque is delayed, for example, the engine 1 needs 3S to change from 0Nm to 200Nm, thereby prolonging the change time, so that the clutch 3 can follow the change of the engine torque after a certain time of buffering, the torque is completely transmitted to the transmission 2, thereby avoiding the occurrence of the vehicle, and ensuring the stability of the vehicle starting.

[0054] In the low temperature condition, when the vehicle meets certain conditions, the torque limit value of the engine is generated according to the actual torque of the vehicle, the first torque compensation value and the second torque compensation value, the torque limit value of the engine is taken as the maximum value of the torque output by the engine, the torque output by the engine is limited in the torque limit value, and the torque change rate of the engine is reduced. Further, by prolonging the response time of the clutch, the clutch can follow the change rate of the engine, and the vehicle can be ensured to start smoothly.

[0055] Figure 3 Another flowchart of the control method for the vehicle to start smoothly provided by the embodiment of the application is provided, and the flowchart is shown in FIG. 12. Figure 3 Optionally, the control method comprises:

[0056] S111: Obtain the starting information of the vehicle.

[0057] S121: Determine whether the vehicle meets the low temperature starting condition according to the starting information.

[0058] Optionally, the low temperature starting condition at least comprises: the temperature of the transmission is greater than or equal to the first temperature threshold value and less than or equal to the second temperature threshold value, the actual speed of the clutch is less than or equal to the clutch speed threshold value corresponding to the opening degree of the throttle at the current time, the vehicle meets the starting control preset condition, and the current gear of the transmission is less than the starting gear threshold value.

[0059] The starting control preset condition is that the difference between the absolute value of the first deviation and the absolute value of the second deviation is greater than the set speed threshold value, wherein the first deviation is the difference between the actual speed of the engine and the actual speed of the clutch at the current time, and the second deviation is the difference between the actual speed of the clutch and the target speed of the engine at the current time.

[0060] The first temperature threshold, the second temperature threshold, the starting gear threshold and the set speed threshold can be set according to user requirements. For example, the first temperature threshold is -40℃, the second temperature threshold is 10℃, the starting gear threshold is 2 gears, and the set speed threshold is 50 rpm. The opening degree of the accelerator is one-to-one corresponding to the clutch speed threshold. For example, at the current moment, when the opening degree of the accelerator is 10%, the clutch speed threshold is 850 rpm, when the opening degree of the accelerator is 50%, the clutch speed threshold is 1200 rpm, and when the opening degree of the accelerator is 80%, the clutch speed threshold is 1800 rpm. The actual speed of the engine is transmitted to the transmission control unit 5 through the driving control unit 4, and the transmission control unit 5 calculates the first deviation according to the actual speed of the engine and the actual speed of the clutch, and calculates the second deviation according to the actual speed of the clutch and the target speed of the engine. The target speed of the engine is determined according to the opening degree of the accelerator, and one opening degree of the accelerator corresponds to one target speed of the engine. When the absolute value of the first deviation and the absolute value of the second deviation are greater than the set speed threshold, it indicates that the vehicle is in the starting stage, and the control process of the torque limitation is triggered only in the starting stage of the vehicle.

[0061] In addition to the temperature of the transmission, the gear of the transmission and whether the vehicle is in the starting stage are also comprehensively judged to determine whether to trigger the torque limiting strategy, so that the control process of the torque limitation does not need to be triggered when the gear of the vehicle is large and the driving force of the vehicle is strong, and the control process of the torque limitation does not need to be triggered when the vehicle ends the starting stage, thereby ensuring that the triggering condition of the control process of the torque limitation is more accurate.

[0062] Optionally, the low-temperature starting condition further includes that the opening degree of the accelerator is greater than a first accelerator threshold, the speed of the vehicle is greater than or equal to a first speed threshold and less than or equal to a second speed threshold, and the actual torque of the engine is greater than a set torque threshold.

[0063] The first accelerator threshold, the first speed threshold, the second speed threshold and the set torque threshold can be set according to user requirements. For example, the first accelerator threshold can be 10%, the first speed threshold can be 1Km / h, the second speed threshold can be 8Km / h, and the set torque threshold can be 40Nm. The low-temperature starting condition meets the above six conditions at the same time, thereby triggering the control process of the torque limitation, avoiding the false triggering of the control process of the torque limitation when the user steps on the accelerator lightly at the initial stage of the starting of the vehicle and then gives up starting the vehicle, and improving the triggering accuracy of the control process of the torque limitation.

[0064] S131: When it is determined that the vehicle meets the low-temperature starting condition, at the current moment, a torque limitation value of the engine is determined according to the actual torque of the engine of the vehicle, a first torque compensation value determined by the temperature value of the transmission of the vehicle, and a second torque compensation value determined by the opening degree of the accelerator of the vehicle and the temperature value of the transmission.

[0065] S141: controlling the torque outputted by the engine according to the torque limit value of the engine, so that the torque outputted by the engine is less than or equal to the torque limit value.

[0066] S151: acquiring the pressure of the clutch of the vehicle or the speed of the vehicle.

[0067] The vehicle further comprises a speed sensor connected with the transmission control unit, so as to transmit the acquired speed of the vehicle to the transmission control unit. The pressure of the transmission can be transmitted to the transmission control unit by the pressure sensor.

[0068] S161: determining whether the clutch meets the following condition according to the pressure of the clutch or the speed of the vehicle.

[0069] The following condition is determined according to the magnitude of the pressure of the clutch and the pressure set value or the magnitude of the speed of the vehicle and the speed set value.

[0070] Optionally, the following condition comprises that the pressure of the clutch is greater than a set pressure threshold value or the speed of the vehicle is greater than or equal to a third speed threshold value; wherein the third speed threshold value is greater than the second speed threshold value, and the second speed threshold value is greater than the first speed threshold value. The set pressure threshold value corresponds to the temperature of the clutch in a one-to-one manner, and the set pressure threshold value is different at different temperatures. When the pressure of the clutch is greater than the set pressure threshold value, it indicates that the clutch can transmit the torque of the engine to the transmission to a greater extent, or when the speed of the vehicle is greater than the third speed threshold value, it indicates that the speed of the vehicle is large, and the vehicle has ended the starting stage.

[0071] S171: when the clutch meets the following condition, determining the torque outputted by the engine according to the torque limit value of the engine at the previous time when the clutch meets the following condition and the torque change rate step length set according to the temperature of the transmission.

[0072] When the vehicle meets the low-temperature starting condition but the clutch does not meet the following condition, the torque outputted by the engine is less than or equal to the torque limit value. When the clutch of the vehicle meets the following condition, it indicates that the clutch can better transmit the torque of the engine to the transmission or the vehicle is about to end the starting stage, and the torque outputted by the engine can be changed to the expected torque quickly through a certain control strategy. Optionally, when the clutch meets the following condition, the torque M outputted by the engine meets the formula:

[0073] M=M0+kt, wherein M0 is the torque limit value of the engine at the previous time when the clutch meets the following condition, k is the torque change rate step length, and t is time.

[0074] The torque change rate step length can be calibrated according to the temperature of the transmission. Table 1 is a corresponding relationship table between the torque change rate step length and the temperature of the transmission.

[0075] Table 1 is a corresponding relationship table between the torque change rate step length and the temperature of the transmission.

[0076] Temperature of the transmission (°C) -40 -30 -20 -10 0 10 Torque change rate step (Nm / 10ms) 1 1.2 1.5 2 2.5 3

[0077] According to Table 1, the torque change rate step length at different temperatures of the transmission can be determined, and then the size of the torque output by the engine can be determined.

[0078] Optionally, after determining the torque output by the engine according to the clutch follow-up condition of the vehicle and the torque change rate step length set according to the temperature of the transmission, the method comprises:

[0079] The actual torque of the engine, the expected torque of the engine and the speed of the vehicle are obtained.

[0080] Specifically, the expected torque of the engine is related to the opening degree of the accelerator pedal, and one opening degree of the accelerator pedal corresponds to one expected torque of the engine.

[0081] According to the actual torque of the engine, the expected torque of the engine and the speed of the vehicle, it is determined whether the vehicle meets the torque limitation exit condition.

[0082] Optionally, the torque limitation exit condition comprises that the absolute value of the difference between the actual torque of the engine and the expected torque of the engine is less than a set torque deviation threshold, or the speed of the vehicle is less than a first speed threshold. The set torque deviation threshold can be set according to user demand. When the absolute value of the difference between the actual torque of the engine and the expected torque of the engine is less than the set torque deviation threshold, it indicates that the deviation between the actual torque of the engine and the expected torque of the engine is small, and the torque limitation control process can be exited. Or, when the speed of the vehicle is less than the first speed, it indicates that the vehicle has a parking trend, and the vehicle is no longer started, and the torque limitation control process can be exited.

[0083] When the engine meets the torque limitation exit condition, the engine is controlled to output torque according to the opening degree of the accelerator pedal.

[0084] When the engine meets the torque limitation exit condition, the vehicle is controlled to perform normal driving operation, that is, the torque output by the engine is determined by the opening degree of the accelerator pedal.

[0085] The embodiment increases the torque slope following link, that is, when the clutch of the vehicle meets the following condition, the torque output by the engine increases according to the torque change rate step, so that the torque output by the engine can change to the expected torque quickly, and the control process of the torque limitation of the engine is smoothly transferred to the expected torque of the driver, and the smooth starting of the vehicle under low temperature conditions is realized.

[0086] Figure 4 A working curve diagram of the vehicle during the low-temperature starting process is provided for the embodiment of the application, Figure 4 The three groups of diagrams include a first group of time and speed relationship curves, the horizontal axis is time T, and the vertical axis is speed RPM, the first group includes three curves: the expected speed of the engine 01, the actual speed of the engine 02 and the actual speed of the clutch 03. The second group is a time and torque relationship curve, the horizontal axis is time T, and the vertical axis is torque Nm, the second group includes three curves: the expected torque of the engine 04, the torque limitation value of the engine 05 and the actual torque of the engine 06. The third group is a visual window diagram, the horizontal axis is time T, and the vertical axis is a control characteristic Bool, the vehicle during the low-temperature starting process includes a torque limitation control stage t1, a torque limitation slope control stage t2 and a driver control stage t3. In the torque limitation control stage t1, the torque output by the engine is less than or equal to the torque limitation value determined according to the actual torque of the engine and the first compensation value and the second compensation value. In the torque limitation slope control stage t2, the torque output by the engine is determined according to the torque limitation value of the engine at the previous time when the clutch meets the following condition and the torque change rate step set according to the temperature of the transmission, so that the torque output by the engine can quickly reach the expected torque. In the driver control stage t3, when the torque output by the engine is equal to the expected torque, the torque output by the engine is controlled by the driver, and the torque output by the engine is determined by the opening degree of the throttle. It is worth noting that the control characteristic is high in the torque limitation control stage t1 and the torque limitation slope control stage t2, and is low in the remaining stages. The low level indicates that the torque output by the engine is completely controlled by the driver. In the prior art, the torque of the engine changes too quickly, for example, from 0Nm to 200Nm within 0.3S. The embodiment prolongs the time of the torque change of the engine from 0Nm to 200Nm through the control of the torque limitation control stage t1 and the torque limitation slope control stage t2, and thus the buffering time of the clutch under low temperature is longer, the clutch can follow the torque change of the engine, and the smooth starting of the vehicle is ensured.

[0087] Figure 5 The flowchart of another vehicle smooth starting control method is provided for the embodiment of the application, referring to Figure 5 Optionally, the vehicle smooth starting control method comprises the following steps.

[0088] S112: The vehicle is in a low-temperature starting working condition.

[0089] Specifically, the temperature of the transmission is acquired, and when the temperature of the transmission is greater than or equal to a first temperature threshold and less than or equal to a second temperature threshold, it is determined that the vehicle is in the low-temperature starting condition.

[0090] S122: Determine whether the vehicle meets the low-temperature starting condition. If yes, perform S132, and if no, perform step S142.

[0091] S132: Implement the torque limiting control process of the engine.

[0092] The transmission implements the torque limiting control process of the engine, which can be specifically referred to S130 and S140, and the present embodiment does not make specific limitations thereto.

[0093] S142: When the vehicle starts, the torque limiting process is not implemented on the engine.

[0094] S152: Determine whether the clutch meets the following condition. If yes, perform S162, and if no, perform S132.

[0095] S162: Implement the torque limiting slope control of the engine.

[0096] Referring to the control process of S171, when the torque limiting slope control of the engine is implemented, the torque output by the engine is determined according to the torque limiting value of the engine at the previous time when the clutch meets the following condition and the torque change rate step set according to the temperature of the transmission.

[0097] S172: Determine whether the engine meets the torque limiting exit condition. If yes, perform S182, and if no, perform S162.

[0098] S182: Exit the torque limiting control process of the engine.

[0099] After exiting the torque limiting control process of the engine, the torque output by the engine is controlled by the user, that is, determined by the opening degree of the throttle.

[0100] The present embodiment also provides a control device for smooth starting of a vehicle, Figure 6 A structural schematic diagram of a control device for smooth starting of a vehicle provided by the present embodiment is shown in Figure 6 The control device comprises:

[0101] A starting information acquisition module 10 is configured to acquire starting information of the vehicle.

[0102] A starting determination module 20 is configured to determine whether the vehicle meets a low-temperature starting condition according to the starting information.

[0103] The torque limit value determination module 30 is configured to determine the torque limit value of the engine according to the actual torque of the engine, a first torque compensation value determined by the temperature value of the transmission of the vehicle, and a second torque compensation value determined by the opening of the accelerator of the vehicle and the temperature value of the transmission when it is determined that the vehicle meets the low-temperature starting condition at the current time.

[0104] The output module 40 is configured to control the torque output by the engine according to the torque limit value of the engine, so that the torque output by the engine is less than or equal to the torque limit value.

[0105] The vehicle smooth starting control device has the same beneficial effects as the vehicle smooth starting control method, and thus the description is not repeated here.

[0106] Optionally, the vehicle smooth starting control device further comprises:

[0107] The pressure and speed acquisition module is configured to acquire the pressure of the clutch of the vehicle or the speed of the vehicle.

[0108] The following condition determination module is configured to determine whether the clutch meets the following condition according to the pressure of the clutch or the speed of the vehicle.

[0109] The slope control output module is configured to determine the torque output by the engine according to the torque limit value of the engine at the previous time when the clutch meets the following condition and the torque change rate step set according to the temperature of the transmission when the clutch meets the following condition.

[0110] Optionally, the vehicle smooth starting control device further comprises:

[0111] The information acquisition module is configured to acquire the actual torque of the engine, the expected torque of the engine, and the speed of the vehicle.

[0112] The exit determination module is configured to determine whether the vehicle meets the torque limit exit condition according to the actual torque of the engine, the expected torque of the engine, and the speed of the vehicle.

[0113] The accelerator control output module is configured to control the engine to output torque according to the opening of the accelerator when the engine meets the torque limit exit condition.

[0114] The embodiment of the application further provides a vehicle comprising the vehicle smooth starting control device, wherein the vehicle smooth starting control device is integrated into the transmission control unit. The vehicle has the same beneficial effects as the vehicle smooth starting control method, and thus the description is not repeated here.

[0115] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps recited in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which are not limited herein.

[0116] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A control method for smooth vehicle start-up, characterized in that, include: Obtain vehicle start-up information; Determine whether the vehicle meets the low-temperature start-up conditions based on the starting information; When it is determined that the vehicle meets the low-temperature start-up conditions, at the current moment, the torque limit value of the engine is determined based on the actual torque of the vehicle's engine, a first torque compensation value determined by the temperature value of the vehicle's transmission, and a second torque compensation value determined by the throttle opening and the temperature value of the transmission. The torque output of the engine is controlled according to the torque limit value of the engine, so that the torque output of the engine is less than or equal to the torque limit value; The low-temperature start conditions include at least the following: the temperature of the transmission is greater than or equal to a first temperature threshold and less than or equal to a second temperature threshold; the actual speed of the clutch is less than or equal to the clutch speed threshold corresponding to the current throttle opening; the vehicle meets the preset start control conditions; and the current gear of the transmission is less than the start gear threshold. The preset condition for starting control is that the difference between the absolute value of the first deviation and the absolute value of the second deviation is greater than a set speed threshold. The first deviation is the difference between the actual speed of the engine and the actual speed of the clutch at the current moment, and the second deviation is the difference between the actual speed of the clutch and the target speed of the engine at the current moment.

2. The vehicle smooth start control method according to claim 1, characterized in that, The low-temperature start-up conditions also include: the throttle opening is greater than a first throttle threshold, the vehicle speed is greater than or equal to a first speed threshold and less than or equal to a second speed threshold, and the actual torque of the engine is greater than a set torque threshold.

3. The vehicle smooth start control method according to claim 2, characterized in that, After controlling the torque output of the engine according to the engine's torque limit value, so that the torque output of the engine is less than or equal to the torque limit value, the method further includes: Obtain the clutch pressure or the speed of the vehicle; Determine whether the clutch meets the following conditions based on the clutch pressure or the vehicle speed; When the clutch meets the following condition, the torque output of the engine is determined based on the engine torque limit value at the moment before the clutch meets the following condition and the torque change rate step size set according to the temperature of the transmission.

4. The vehicle smooth start control method according to claim 3, characterized in that, The following conditions include: the clutch pressure is greater than a set pressure threshold, or the vehicle speed is greater than or equal to a third speed threshold; wherein the third speed threshold is greater than the second speed threshold.

5. The vehicle smooth start control method according to claim 3, characterized in that, The step of determining the engine output torque based on the engine torque limit value at the moment preceding the clutch meeting the following conditions and the torque change rate step size set according to the temperature of the transmission when the clutch meets the following conditions includes: The torque M output by the engine conforms to the formula: M = M0 + kt, where M0 is the torque limit value of the engine at the moment before the clutch meets the following condition, k is the torque change rate step size, and t is time.

6. The vehicle smooth start control method according to claim 3, characterized in that, After determining the engine output torque based on the engine torque limit value at the moment preceding the vehicle's clutch meeting the following conditions and the torque change rate step size set according to the transmission temperature, the process includes: Obtain the actual torque of the engine, the desired torque of the engine, and the speed of the vehicle; Determine whether the vehicle meets the torque limit exit conditions based on the engine's actual torque, the engine's desired torque, and the vehicle's speed; When the engine meets the torque limit exit condition, the engine is controlled to output torque according to the throttle opening.

7. The vehicle smooth start control method according to claim 6, characterized in that, The torque limit exit conditions include: the absolute value of the difference between the actual torque of the engine and the expected torque of the engine is less than a set torque deviation threshold, or the speed of the vehicle is less than a first speed threshold.

8. A control device for smooth vehicle start-up, characterized in that, include: The starting information acquisition module is used to acquire the vehicle's starting information; The starting determination module is used to determine whether the vehicle meets the low-temperature starting conditions based on the starting information. The torque limit value determination module is used to determine the engine torque limit value at the current moment when it is determined that the vehicle meets the low temperature start-up conditions, based on the actual torque of the vehicle's engine, a first torque compensation value determined by the temperature value of the vehicle's transmission, and a second torque compensation value determined by the throttle opening and the temperature value of the transmission. An output module is used to control the torque output by the engine according to the torque limit value of the engine, so that the torque output by the engine is less than or equal to the torque limit value; The low-temperature start conditions include at least the following: the temperature of the transmission is greater than or equal to a first temperature threshold and less than or equal to a second temperature threshold; the actual speed of the clutch is less than or equal to the clutch speed threshold corresponding to the current throttle opening; the vehicle meets the preset start control conditions; and the current gear of the transmission is less than the start gear threshold. The preset condition for starting control is that the difference between the absolute value of the first deviation and the absolute value of the second deviation is greater than a set speed threshold. The first deviation is the difference between the actual speed of the engine and the actual speed of the clutch at the current moment, and the second deviation is the difference between the actual speed of the clutch and the target speed of the engine at the current moment.

9. A vehicle, characterized in that, Includes the vehicle smooth start control device as described in claim 8.

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