A control method, device, system and vehicle for hill start

Abstract

The embodiment of the application provides a control method, device and system of hill start and vehicle, relates to the vehicle control technical field, can carry out pressure compensation to the vehicle with the worm function when starting on the hill, thereby avoiding the vehicle from sliding when starting; meanwhile, pressure relief can be carried out at the appropriate time, thereby ensuring the normal start of the vehicle. The control method of hill start comprises the following steps: in response to the hill start auxiliary function of the vehicle being in the open state, determining the minimum driving torque under the current slope value; in response to reaching the exit condition of the hill start auxiliary function, controlling the hill start auxiliary function to exit; according to the relative size between the minimum driving torque and the maximum worm torque, exerting a target pressure on the wheels of the vehicle; receiving the actual driving torque curve from the vehicle controller; within the time range in which the actual driving torque increases to the minimum driving torque, the target pressure is reduced to 0, so as to control the vehicle to start after reaching the minimum driving torque.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of vehicle control, and particularly relate to a control method, device, system and vehicle for hill start. BACKGROUND

[0002] Currently, for a vehicle with a crawling function, if the driver wants to start on a hill after temporarily parking on the hill and starting the hill start assist function, the following two problems may occur after the hill start assist function is exited: first, the vehicle may slide when starting due to the crawling torque being less than the minimum drive torque of the vehicle on the current hill; second, even if the crawling torque is greater than the minimum drive torque of the current hill, the vehicle may still slide when starting due to the crawling torque increasing taking a certain amount of time. SUMMARY

[0003] Embodiments of the present application provide a control method, device, system and vehicle for hill start, which can compensate for pressure when a vehicle with a crawling function starts on a hill, thereby avoiding the vehicle from sliding during starting, and can also release pressure at an appropriate time, thereby ensuring normal starting of the vehicle.

[0004] In a first aspect, embodiments of the present application provide a control method for hill start, the method comprising:

[0005] in response to a hill start assist function of a vehicle being in an enabled state, determining a minimum drive torque at a current slope value, the minimum drive torque being a minimum torque for the vehicle to enter a running state from a stationary state;

[0006] in response to a condition for exiting the hill start assist function being met, controlling the hill start assist function to exit;

[0007] applying a target pressure to wheels of the vehicle according to a relative size between the minimum drive torque and a maximum crawling torque, wherein the vehicle is in a stationary state at the current slope value under the target pressure;

[0008] receiving an actual drive torque curve from a vehicle control unit;

[0009] in a time range in which an actual drive torque in the actual drive torque curve increases to the minimum drive torque, reducing the target pressure to 0, so that the actual drive torque controls the vehicle to start after the minimum drive torque is reached.

[0010] In the embodiments of the present application, when the slope starting assist function of the vehicle is in an open state, the minimum drive torque required for starting on the current slope can be determined, and then after the slope starting assist function is exited, the relative size between the minimum drive torque and the maximum creep torque can be used to compensate the pressure of the wheels of the vehicle, so that the vehicle can be kept stationary on the current slope under the action of the pressure, and the vehicle from rolling. On this basis, in the process that the actual drive torque of the vehicle gradually increases to the minimum drive torque, the compensated pressure is gradually reduced to 0, that is, when the actual drive torque increases to the minimum drive torque, the compensated pressure is just reduced to 0, so that the vehicle can be controlled to start in time based on the minimum drive torque, avoiding the problem of starting delay caused by slow pressure release when the actual drive torque increases to the minimum drive torque, and also avoiding the problem of rolling caused by too fast pressure release before the actual drive torque increases to the minimum drive torque.

[0011] Optionally, the target pressure applied to the wheels of the vehicle according to the relative size between the minimum drive torque and the maximum creep torque comprises:

[0012] In response to determining that the minimum drive torque is less than the maximum creep torque, a first pressure is used as the target pressure, wherein the first pressure is the pressure required to keep the vehicle stationary on the maximum creep slope corresponding to the maximum creep torque.

[0013] The first pressure is applied to the wheels.

[0014] In the embodiments of the present application, if the minimum drive torque is less than the maximum creep torque, it indicates that the current slope of the vehicle is less than or equal to the maximum creep slope corresponding to the maximum creep torque, and therefore the pressure required to keep the vehicle stationary on the maximum creep slope is used as the compensation pressure of the vehicle on the current slope, which can ensure that the vehicle will not roll.

[0015] Optionally, the target pressure applied to the wheels of the vehicle according to the relative size between the minimum drive torque and the maximum creep torque comprises:

[0016] In response to determining that the minimum drive torque is greater than the maximum creep torque, a second pressure value corresponding to the current slope value is determined; the second pressure is the pressure required to keep the vehicle stationary when there is a creep torque at the current slope value;

[0017] The second pressure is used as the target pressure, and the second pressure is applied to the wheels.

[0018] In the embodiments of the present application, if the minimum driving torque is greater than the maximum crawling torque, it indicates that the current slope is already greater than the maximum crawling slope corresponding to the maximum crawling torque, and thus the pressure corresponding to the current slope can be determined according to the corresponding relationship between the slope value greater than the maximum crawling slope and the pressure required for maintaining the vehicle stationary when the crawling torque exists, and the pressure is taken as the compensation pressure of the vehicle at the current slope, which can ensure that the vehicle will not roll.

[0019] Optionally, the target pressure is reduced to 0 in a time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, including:

[0020] According to the minimum driving torque corresponding to the maximum crawling slope and the preset torque slope, a reference time length required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum crawling slope is determined;

[0021] According to the reference time length, the current slope value and the maximum crawling slope, a first actual time length required for the actual driving torque to increase to the minimum driving torque corresponding to the current slope value is determined;

[0022] The target pressure is reduced to 0 in the first actual time length.

[0023] In the embodiments of the present application, since the minimum driving torque corresponding to the maximum crawling slope and the preset torque slope of the crawling torque growth in the vehicle controller are known, the reference time length required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum crawling slope can be determined. On this basis, since the current slope is less than the maximum crawling slope, the minimum driving torque corresponding to the current slope is necessarily less than the minimum driving torque corresponding to the maximum crawling slope, and thus the time for the crawling torque to reach the minimum driving torque corresponding to the current slope is also necessarily less than the time for the crawling torque to reach the minimum driving torque corresponding to the maximum crawling slope. Therefore, according to the reference time length, the current slope and the maximum crawling slope, the actual time length for the crawling torque to reach the minimum driving torque corresponding to the current slope can be determined, and then the compensation pressure is released in the actual time length, so that the vehicle can be controlled to start in time based on the minimum driving torque corresponding to the current slope, avoiding the start delay problem caused by slow pressure release when the actual driving torque increases to the minimum driving torque of the current slope, and also avoiding the rolling problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0024] Optionally, the target pressure is reduced to 0 in the actual time length, including:

[0025] According to the first actual time length and the target pressure, an actual pressure release slope is determined.

[0026] decreasing the target pressure to 0 based on the actual pressure relief slope within the first actual time length.

[0027] In the embodiments of the present application, the actual pressure relief slope can be determined according to the target pressure and the first actual time length, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the first actual time length, so as to avoid the problem of vehicle slipping caused by too fast pressure relief in the early stage of pressure relief.

[0028] Optionally, within a time range in which the actual drive torque in the actual drive torque curve increases to the minimum drive torque, the target pressure is decreased to 0, comprising:

[0029] determining a first slope at which the driver requested torque increases to the maximum creep torque;

[0030] determining a second actual time length at which the actual drive torque increases from the maximum creep torque to the minimum drive torque based on the first slope;

[0031] in response to determining that the actual drive torque increases to the maximum creep torque, decreasing the target pressure to 0 within the second actual time length.

[0032] In the embodiment of the present application, in the case that the maximum creep torque is less than the minimum driving torque corresponding to the current slope, the user needs to step on the accelerator pedal to generate additional driving force. Once the user steps on the accelerator pedal, the vehicle control unit determines the driver request torque according to the accelerator pedal opening. At this time, if the driver request torque is less than the maximum creep torque, it can be considered that the vehicle control unit will not respond to the driver request torque, but will output based on the maximum creep torque, but the electronic stability control system can calculate the first slope of the increase of the driver request torque from 0 to the maximum creep torque. When the driver request torque exceeds the maximum creep torque, the creep torque exits, and the vehicle control unit takes the driver request torque as the actual driving torque. Since the increase of the driver request torque from 0 to the maximum creep torque is based on the first slope, theoretically, the increase of the driver request torque from the maximum creep torque to the minimum driving torque should also be based on the first slope. Therefore, the second actual time length of the increase of the driver request torque from the maximum creep torque to the minimum driving torque can be determined based on the first slope. After the driver request torque reaches the maximum creep torque, that is, after the additional driving force is generated by stepping on the accelerator pedal, the supplementary pressure is released within the second actual time length, so that the vehicle can be controlled to start in time based on the minimum driving torque corresponding to the current slope, avoiding the start delay problem caused by slow pressure release when the actual driving torque increases to the minimum driving torque of the current slope, and avoiding the problem of coasting caused by fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0033] Optionally, before the target pressure is reduced to 0 within the second actual time length, the method further comprises:

[0034] determining a real-time slope of the increase of the driver request torque from the maximum creep torque to the minimum driving torque corresponding to the current slope;

[0035] determining a corrected second actual time length according to the first slope, the real-time slope, and the second actual time length;

[0036] in response to determining that the actual driving torque increases to the maximum creep torque, reducing the target pressure to 0 within the second actual time length, comprising:

[0037] in response to determining that the actual driving torque increases to the maximum creep torque, reducing the target pressure to 0 within the corrected second actual time length.

[0038] In the embodiments of the present application, the first slope can be considered as an ideal slope of the driver request torque increasing from the maximum creep torque to the minimum drive torque corresponding to the current slope, and the real-time slope can be considered as a real slope of the driver request torque increasing from the maximum creep torque to the minimum drive torque corresponding to the current slope. Then, according to the first slope, the real-time slope and the second actual time length, a modified second actual time length available for pressure relief can be determined, and then pressure relief is performed within the modified second actual time length, so as to ensure the accuracy of the pressure relief time range, avoid the start delay problem caused by late pressure release, and also avoid the coasting problem caused by early pressure release.

[0039] Optionally, in response to determining that the actual drive torque increases to the maximum creep torque, the target pressure is reduced to 0 within the modified second actual time length, comprising:

[0040] In response to determining that the actual drive torque increases to the maximum creep torque, an actual pressure relief slope is determined according to the target pressure and the modified second actual time length;

[0041] The target pressure is reduced to 0 within the modified second actual time length according to the actual pressure relief slope.

[0042] In the embodiments of the present application, the actual pressure relief slope can be determined according to the target pressure and the modified second actual time length, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the modified second actual time length, so as to avoid the coasting problem caused by too fast pressure relief in the early stage of pressure relief.

[0043] In a second aspect, the embodiments of the present application provide a control device for hill start, comprising:

[0044] A determination unit is configured to determine a minimum drive torque at a current slope value in response to a hill start assist function of a vehicle being in an open state, the minimum drive torque being a minimum torque for the vehicle to enter a running state from a stationary state;

[0045] A control unit is configured to control the hill start assist function to exit in response to an exit condition of the hill start assist function being met;

[0046] A pressurization unit is configured to apply a target pressure to wheels of the vehicle according to a relative size between the minimum drive torque and a maximum creep torque, wherein the vehicle is in a stationary state at the current slope value under the action of the target pressure;

[0047] A receiving unit is configured to receive an actual drive torque curve from a vehicle control unit;

[0048] A pressure relief unit is configured to reduce the target pressure to 0 in a time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, so that the actual driving torque controls the vehicle to start after reaching the minimum driving torque.

[0049] Optionally, the pressure increasing unit is specifically configured to:

[0050] In response to determining that the minimum driving torque is less than the maximum creep torque, the first pressure is determined as the target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep slope corresponding to the maximum creep torque.

[0051] The first pressure is applied to the wheels.

[0052] Optionally, the pressure increasing unit is specifically configured to:

[0053] In response to determining that the minimum driving torque is greater than the maximum creep torque, a second pressure value corresponding to the current slope value is determined; the second pressure is a pressure required to maintain the vehicle stationary when there is a creep torque at the current slope value.

[0054] The second pressure is determined as the target pressure, and the second pressure is applied to the wheels.

[0055] Optionally, the pressure relief unit includes:

[0056] A reference time length determination sub-unit is configured to determine a reference time length required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum creep slope according to the minimum driving torque corresponding to the maximum creep slope and a preset torque slope.

[0057] An actual time length determination sub-unit is configured to determine a first actual time length required for the actual driving torque to increase to the minimum driving torque corresponding to the current slope value according to the reference time length, the current slope value, and the maximum creep slope.

[0058] A pressure relief sub-unit is configured to reduce the target pressure to 0 in the first actual time length.

[0059] Optionally, the pressure relief sub-unit is configured to:

[0060] An actual pressure relief slope is determined according to the first actual time length and the target pressure.

[0061] The target pressure is reduced to 0 based on the actual pressure relief slope in the first actual time length.

[0062] Optionally, the pressure relief unit includes:

[0063] a slope determination sub-unit configured to determine a first slope of the driver-requested torque increasing to the maximum creep torque;

[0064] a real duration determination sub-unit configured to determine a second real duration of the actual driving torque increasing from the maximum creep torque to the minimum driving torque based on the first slope;

[0065] a pressure relief sub-unit configured to reduce the target pressure to 0 within the second real duration in response to determining that the actual driving torque increases to the maximum creep torque.

[0066] Optionally, the slope determination sub-unit is further configured to:

[0067] determine a real-time slope of the driver-requested torque increasing from the maximum creep torque to the minimum driving torque corresponding to a current slope;

[0068] the real duration determination sub-unit is further configured to:

[0069] determine a corrected second real duration based on the first slope, the real-time slope and the second real duration;

[0070] the pressure relief sub-unit is specifically configured to:

[0071] reduce the target pressure to 0 within the corrected second real duration in response to determining that the actual driving torque increases to the maximum creep torque.

[0072] Optionally, the pressure relief sub-unit is specifically configured to:

[0073] determine an actual pressure relief slope based on the target pressure and the corrected second real duration in response to determining that the actual driving torque increases to the maximum creep torque;

[0074] reduce the target pressure to 0 within the corrected second real duration according to the actual pressure relief slope.

[0075] In a third aspect, an embodiment of the present application provides an electronic stability control system, the electronic stability control system comprising a memory for storing computer program instructions and a processor for executing the program instructions, wherein when the computer program instructions are executed by the processor, the electronic stability control system is triggered to perform the steps of the method according to any embodiment of the first aspect.

[0076] In a fourth aspect, an embodiment of the present application provides a vehicle, the vehicle comprising the electronic stability control system according to the third aspect.

[0077] In a fifth aspect, an embodiment of the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions make a computer execute steps of the method according to any one of the embodiments of the first aspect when the computer runs.

[0078] It should be understood that the second to fifth aspects of the embodiments of the present application are consistent with the technical solution of the first aspect of the embodiments of the present application, and the beneficial effects obtained by each aspect and the corresponding feasible implementation manners are similar, and will not be repeated. BRIEF DESCRIPTION OF DRAWINGS

[0079] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows. 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.

[0080] Figure 1 A flowchart of a control method for ramp starting provided by an embodiment of the present application;

[0081] Figure 2 A flowchart of a method for applying a target pressure to a wheel provided by an embodiment of the present application;

[0082] Figure 3 A flowchart of another method for applying a target pressure to a wheel provided by an embodiment of the present application;

[0083] Figure 4 A flowchart of a method for relieving a target pressure provided by an embodiment of the present application;

[0084] Figure 5 A flowchart of a method for relieving pressure provided by an embodiment of the present application;

[0085] Figure 6 A flowchart of another method for relieving a target pressure provided by an embodiment of the present application;

[0086] Figure 7 A flowchart of another method for relieving a target pressure provided by an embodiment of the present application;

[0087] Figure 8 A flowchart of a method for relieving pressure provided by an embodiment of the present application;

[0088] Figure 9 A control device for ramp starting provided by an embodiment of the present application;

[0089] Figure 10A structural schematic diagram of an electronic stability control system is provided for an embodiment of the present application.

[0090] Figure 11 A structural schematic diagram of a vehicle is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0091] In order to better understand the technical solutions of the present specification, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0092] It should be clear that the described embodiments are only part of the embodiments of the present specification, rather than all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present specification.

[0093] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present specification. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0094] At present, the crawling function is generally configured in new energy vehicles. The crawling function refers to the function that when the vehicle is in the forward gear (D gear) or the reverse gear (R gear) and the accelerator pedal and the brake pedal are not stepped on, the vehicle will slowly drive at a certain speed, and a maximum crawling torque, i.e. a maximum crawling torque, will be set to ensure that the vehicle drives at a set speed on a certain slope (maximum crawling slope).

[0095] For a vehicle with a crawling function, if the driver wants to start on the slope after temporarily parking on the slope and starting the slope start assist function, the following two problems may occur after the slope start assist function is exited: first, the vehicle may slide when starting due to the crawling torque being less than the minimum drive torque of the vehicle on the current slope; second, even if the crawling torque is greater than the minimum drive torque of the current slope, the vehicle may still slide when starting due to the time required for the crawling torque to increase.

[0096] In view of this, the embodiments of the present application provide a control method for slope starting. In the method, the electronic stability control system can combine the relative size between the minimum drive torque required for the vehicle to start on the current slope and the maximum crawling torque that the vehicle can provide to compensate the pressure of the vehicle, so as to avoid the vehicle from sliding when starting. During the process of the actual drive torque of the vehicle increasing to the minimum drive torque, the compensated pressure is gradually reduced to 0, so that the vehicle can be controlled to start in time based on the above minimum drive torque.

[0097] The technical solutions protected by the embodiments of the present application will be described in detail below with reference to the drawings.

[0098] Please refer to Figure 1 A control method for hill start provided by the embodiments of the present application is applied to an electronic stability control system (ESC), and the flow of the method is described as follows.

[0099] Step 101: In response to the hill start assist function of the vehicle being in an open state, the minimum driving torque under the current slope value is determined.

[0100] In the embodiments of the present application, when the driver makes the vehicle stationary on the current hill by stepping on the brake pedal, if it is detected that the brake pedal opening is less than a set threshold, it can be considered that the driver releases the brake pedal, at which time the hill start assist function is triggered to be opened. When the hill start assist function is opened, it can be considered that the target time length of brake force is applied to the vehicle, so that even if the driver releases the brake pedal, the vehicle can be stationary on the current hill within the target time length after the driver releases the brake pedal. At this time, the ESC can obtain the current hill value of the current hill, and then determine the minimum driving torque corresponding to the current slope value according to the pre-stored corresponding relationship between the slope value and the minimum driving torque. It should be understood that the minimum driving torque here can be considered as the minimum torque required for driving the vehicle to start (from stationary to start driving) under the current slope value.

[0101] Step 102: In response to reaching the exit condition of the hill start assist function, the hill start assist function is controlled to exit.

[0102] In the embodiments of the present application, the ESC starts timing from the time when the brake pedal opening is less than the set threshold. If the timing duration reaches the preset duration, it is considered that the vehicle has had enough time to start after releasing the brake pedal, and therefore the hill start assist function can be controlled to exit.

[0103] Step 103: According to the relative size between the minimum driving torque and the maximum creep torque, a target pressure is applied to the wheels of the vehicle.

[0104] In the embodiments of the present application, after the hill start assist function exits, the brake force provided by the function naturally disappears. At this time, the ESC can determine the target pressure applied to the brake master cylinder of the vehicle according to the relative size between the minimum driving torque corresponding to the current slope and the maximum creep torque of the creep function of the vehicle. It should be understood that since the pressure in the brake master cylinder acts on the wheels, the target pressure here can also be considered as the pressure acting on the vehicle.

[0105] The following will be described in detail for different situations on how to apply a target pressure to the wheels.

[0106] Case one: the minimum driving torque corresponding to the current slope is less than the maximum creep torque.

[0107] Please refer to Figure 2 , a flowchart of a method for applying a target pressure to the wheels is provided. Step 103 can be implemented by executing sub-step 1031 and sub-step 1032.

[0108] Step 1031: in response to determining that the minimum driving torque is less than the maximum creep torque, the first pressure is taken as the target pressure, wherein the first pressure is the pressure required to maintain the vehicle stationary on the maximum creep slope corresponding to the maximum creep torque.

[0109] Step 1032: apply the first pressure to the wheels.

[0110] In the present embodiment, if the minimum driving torque is less than the maximum creep torque, it indicates that the current slope of the vehicle is less than or equal to the maximum creep slope corresponding to the maximum creep torque, so the pressure required to maintain the vehicle stationary on the maximum creep slope is applied to the wheels as the compensation pressure of the vehicle on the current slope, which can ensure that the vehicle will not roll under the action of the compensation pressure.

[0111] For example, the maximum creep torque is the creep torque that makes the vehicle travel at a set speed on a 10% slope, and the maximum creep slope corresponding to the maximum creep torque is 10%. Since the minimum driving torque of the current slope is less than the maximum creep torque, it can be considered that the current slope is less than or equal to the maximum creep slope (10%), so the first pressure required to maintain the vehicle stationary on a 10% slope can be taken as the target pressure.

[0112] Case two: the minimum driving torque corresponding to the current slope is greater than the maximum creep torque.

[0113] Please refer to Figure 3 , another flowchart of a method for applying a target pressure to the wheels is provided. Step 103 can be implemented by executing sub-step 1033 and sub-step 1034.

[0114] Step 1033: in response to determining that the minimum driving torque is greater than the maximum creep torque, the second pressure value corresponding to the current slope value is determined; the second pressure is the pressure required to maintain the vehicle stationary when there is a creep torque on the current slope value.

[0115] Step 1034: take the second pressure as the target pressure and apply the second pressure to the wheels.

[0116] In the embodiments of the present application, if the minimum driving torque is greater than the maximum crawling torque, it indicates that the current slope where the vehicle is located is already greater than the maximum crawling slope corresponding to the maximum crawling torque. Therefore, the pressure corresponding to the current slope can be determined according to the corresponding relationship between the slope value greater than the maximum crawling slope and the pressure required for maintaining the vehicle stationary when the crawling torque exists, and the pressure is applied to the wheel end as the compensation pressure of the vehicle at the current slope, so as to ensure that the vehicle will not slide when the crawling torque and the compensation pressure act simultaneously.

[0117] For example, if the maximum crawling slope is 10% and the minimum driving torque is greater than the maximum crawling torque, it indicates that the current slope where the vehicle is located is already greater than the maximum crawling slope (10%). The ESC has previously established the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 15% slope value, the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 20% slope value, the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 25% slope value, and the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 30% slope value. If the current slope value is 15%, the pressure required for maintaining the vehicle stationary when the crawling torque exists corresponding to the current slope value is determined; if the current slope value is between 15% and 20%, the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 15% slope value is calculated, and the pressure average of the pressure required for maintaining the vehicle stationary when the crawling torque exists at the 20% slope value is calculated, and the pressure average is applied to the wheel end as the target pressure.

[0118] Step 104: receiving the actual driving torque curve from the vehicle control unit.

[0119] In the embodiments of the present application, after the ESC applies the target pressure to the wheel end, it can be ensured that the vehicle is stationary at the current slope after the hill start assist function is exited. At this time, the vehicle control unit (VCU) can control the actual driving torque to be output, and the actual driving torque can be the crawling torque or the torque generated by the driver stepping on the accelerator pedal, which will be described in detail below. Meanwhile, the VCU also sends the actual driving torque curve formed by the actual driving torque to the ESC.

[0120] Step 105: in the time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, the target pressure is reduced to 0, so as to control the vehicle to start after the actual driving torque reaches the minimum driving torque.

[0121] In the embodiment of the present application, the ESC can determine the time range in which the actual drive torque increases to the minimum drive torque from the actual drive torque curve received from the VCU, and then gradually reduce the target pressure to 0 within the time range, that is, the target pressure to be compensated is just reduced to 0 when the actual drive torque increases to the minimum drive torque, so that the vehicle can be controlled to start in time based on the minimum drive torque, avoiding the start delay problem caused by slow pressure release when the actual drive torque increases to the minimum drive torque, and also avoiding the coasting problem caused by too fast pressure release before the actual drive torque increases to the minimum drive torque.

[0122] The way of reducing the target pressure to 0 under different conditions will be described in detail below.

[0123] Case one: the minimum drive torque corresponding to the current slope is less than the maximum creep torque, then the pressure is released from when the actual drive torque has a trend of increasing.

[0124] Please refer to Figure 4 A flowchart of a method for releasing the target pressure provided in the embodiment of the present application is shown in FIG. 5. Step 105 can be realized by executing sub-step 1051 to sub-step 1053.

[0125] Step 1051: determining the reference time length required for the actual drive torque to increase to the minimum drive torque corresponding to the maximum creep slope according to the minimum drive torque corresponding to the maximum creep slope and the preset torque slope.

[0126] Step 1052: determining the first actual time length required for the actual drive torque to increase to the minimum drive torque corresponding to the current slope value according to the reference time length, the current slope value and the maximum creep slope.

[0127] In the embodiment of the present application, in the case where the minimum drive torque corresponding to the current slope is less than the maximum creep torque, the start of the vehicle mainly depends on the creep torque. Since the minimum drive torque corresponding to the maximum creep slope and the preset torque slope of the creep torque growth in the vehicle controller are known, the ratio of the minimum drive torque corresponding to the maximum creep slope and the preset torque slope can be calculated, so as to determine the reference time length required for the actual drive torque to increase to the minimum drive torque corresponding to the maximum creep slope. On this basis, since the current slope is less than the maximum creep slope, the time for the creep torque to reach the minimum drive torque corresponding to the current slope is also necessarily less than the time for the creep torque to reach the minimum drive torque corresponding to the maximum creep slope, therefore, the first actual time length for the creep torque to reach the minimum drive torque corresponding to the current slope can be determined according to the reference time length, the current slope and the maximum creep slope. The calculation method of the first actual time length is shown in formula (1):

[0128] (1)

[0129] wherein, t1 represents the first actual duration, t0 represents the reference duration, x represents the current slope, x max represents the maximum creep slope.

[0130] It is worth noting that in the embodiments of the present application, the first actual duration can also be directly determined based on the ratio of the minimum driving torque corresponding to the current slope to the preset torque slope.

[0131] Step 1053: reducing the target pressure to 0 within the first actual duration.

[0132] After calculating the first actual duration, if the ESC determines that the actual driving torque has an increasing trend through the actual driving torque curve, the supplementary first pressure is depressurized within the first actual duration, so that the vehicle can be controlled to start in time based on the minimum driving torque corresponding to the current slope, avoiding the start delay problem caused by slow pressure release when the actual driving torque increases to the minimum driving torque of the current slope, and also avoiding the coasting problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0133] In some embodiments, considering that the VCU loads the creep torque based on the fixed preset torque slope, in the embodiments of the present application, a fixed pressure release slope can also be used for pressure release during the pressure release process, avoiding the coasting problem caused by too fast pressure release in the early stage of pressure release.

[0134] Please refer to Figure 5 , a flowchart of a pressure release method provided by the embodiments of the present application. Step 1053 can be implemented by executing sub-step 10531 to sub-step 10532:

[0135] Step 10531: determining the actual pressure release slope according to the first actual duration and the target pressure.

[0136] Step 10532: reducing the target pressure to 0 based on the actual pressure release slope within the first actual duration.

[0137] In the embodiments of the present application, the actual pressure release slope can be determined according to the target pressure and the first actual duration, and then the target pressure is uniformly depressurized based on the determined actual pressure release slope within the first actual duration, avoiding the coasting problem caused by too slow growth of the creep torque due to too fast pressure release in the early stage of pressure release. Of course, a slow-to-fast pressure release mode can also be used, that is, the actual pressure release slope can be small first and large later for pressure release within the second actual duration after correction.

[0138] Case two: when the minimum driving torque corresponding to the current slope is greater than the maximum crawling torque, the actual driving torque is increased to the maximum crawling torque, and then the pressure is released.

[0139] Please refer to Figure 6 Another flowchart of the method for releasing pressure to the target pressure is provided in the embodiments of the present application. Step 105 can be implemented by executing sub-step 1054 to sub-step 1056.

[0140] Step 1054: determining a first slope at which the driver-requested torque is increased to the maximum crawling torque.

[0141] Step 1055: determining a second actual time length at which the actual driving torque is increased from the maximum crawling torque to the minimum driving torque based on the first slope.

[0142] In the embodiments of the present application, when the minimum driving torque corresponding to the current slope is greater than the maximum crawling torque, the start of the vehicle mainly depends on the combined action of the crawling torque and the driving force generated by the driver stepping on the driving pedal. After the user steps on the accelerator pedal, the vehicle control unit detects the accelerator pedal opening, and then determines the driver-requested torque based on the accelerator pedal opening. At this time, if the driver-requested torque is less than the maximum crawling torque, the vehicle control unit will not respond to the driver-requested torque, but will output based on the maximum crawling torque, but the vehicle control unit will send the driver-requested torque to the ESC. The ESC records the corresponding time stamp while receiving the driver-requested torque from the VCU, and then the ESC can determine the first slope according to the time at which the maximum crawling torque and the driver-requested torque increase from 0 to the maximum crawling torque. When the VCU determines that the driver-requested torque exceeds the maximum crawling torque, the VCU will control the crawling torque to exit, and the vehicle control unit will take the driver-requested torque as the actual driving torque. Since the driver-requested torque increases from 0 to the maximum crawling torque based on the first slope when the driver steps on the accelerator pedal, theoretically, the driver-requested torque increases from the maximum crawling torque to the minimum driving torque based on the first slope after the driver-requested torque is taken as the actual driving torque. Therefore, the second actual time length at which the driver-requested torque increases from the maximum crawling torque to the minimum driving torque can be determined based on the above first slope.

[0143] Step 1056: in response to determining that the actual driving torque increases to the maximum crawling torque, the target pressure is reduced to 0 within the second actual time length.

[0144] In the embodiments of the present application, before the driver request torque is greater than the maximum creep torque, although the driver steps on the accelerator pedal, no additional driving torque can be generated, at this time, the vehicle is still maintained stationary by relying on the combined action of the creep torque and the applied target pressure, therefore, before the driver request torque is greater than the maximum creep torque, the target pressure cannot be released, and once released, the vehicle will slide. After the driver request torque is greater than the maximum creep torque, the creep torque is withdrawn, and the driver request torque plays a role equivalent to generating additional driving torque on the basis of the creep torque, therefore, in the case of generating additional driving torque, the target pressure can be gradually released within the second actual time, so that the vehicle is controlled to start in time when the driver request torque reaches the minimum driving torque corresponding to the current slope, avoiding the problem of start delay caused by slow pressure release when the driver request torque increases to the minimum driving torque of the current slope, and also avoiding the problem of sliding caused by too fast pressure release before the driver request torque increases to the minimum driving torque of the current slope.

[0145] In some embodiments, the slope of the driver request torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope can be the same as the slope of the driver request torque increasing from 0 to the maximum creep torque, or can be different. Therefore, in the embodiments of the present application, the second actual time can be corrected based on the first slope and the slope of the driver request torque increasing from the maximum creep torque to the minimum driving torque, so as to ensure that the target pressure can be released more accurately.

[0146] Please refer to Figure 7 Another flowchart of a method for releasing the target pressure provided by the embodiments of the present application is shown in FIG. 10. Before step 1056 is performed, steps 1057 to 1058 can also be performed.

[0147] Step 1057: determining the real-time slope of the driver request torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope.

[0148] Step 1058: determining the corrected second actual time according to the first slope, the real-time slope and the second actual time.

[0149] Step 1056 can be implemented by performing sub-step 10561:

[0150] Step 10561: in response to determining that the actual driving torque increases to the maximum creep torque, the target pressure is reduced to 0 within the corrected second actual time.

[0151] In the embodiments of the present application, the first slope can be considered as an ideal slope of the driver request torque increasing from the maximum creep torque to the minimum drive torque corresponding to the current slope, and the real-time slope can be considered as a real slope of the driver request torque increasing from the maximum creep torque to the minimum drive torque corresponding to the current slope. Then, the corrected second actual time length available for pressure relief can be determined according to the first slope, the real-time slope, and the second actual time length. The calculation formula of the corrected second actual time length is shown in formula (2):

[0152] (2)

[0153] wherein, represents the corrected second actual time length, t2 represents the second actual time length, k1 represents the first slope, and k2 represents the real-time slope. It should be understood that the greater k2 is, the smaller , that is, the faster the speed of the driver request torque increasing from the maximum creep torque to the minimum drive torque corresponding to the current slope, and correspondingly, the faster the pressure relief speed needs to be.

[0154] After the corrected second actual time length is determined, the pressure relief can be performed within the corrected second actual time length, so as to ensure the accuracy of the pressure relief time range, avoid the start-up delay problem caused by late pressure release, and also avoid the coasting problem caused by early pressure release.

[0155] In some embodiments, when the target pressure is relieved, the pressure relief can be performed based on a fixed pressure relief slope, so as to avoid the coasting problem caused by too fast pressure relief in the early stage of pressure relief.

[0156] Please refer to Figure 8 , a flowchart of a pressure relief method provided in the embodiments of the present application. Step 10561 can be implemented by executing sub-step 201 to sub-step 202:

[0157] Step 201: In response to determining that the actual drive torque increases to the maximum creep torque, an actual pressure relief slope is determined according to the target pressure and the corrected second actual time length.

[0158] Step 202: The target pressure is reduced to 0 according to the actual pressure relief slope within the corrected second actual time length.

[0159] In the embodiments of the present application, the actual pressure relief slope can be determined according to the target pressure and the corrected second actual time length, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the corrected second actual time length, so as to avoid the problem of vehicle slipping caused by too fast pressure relief in the early stage of pressure relief. Of course, the pressure relief mode of slow first and then fast can also be adopted, that is, the actual pressure relief slope can be small first and then large for pressure relief within the corrected second actual time length.

[0160] Please refer to Figure 9 Based on the same inventive concept, the embodiments of the present application provide a control device for hill start, which comprises:

[0161] A determination unit 301 is configured to determine a minimum driving torque at a current slope value in response to the hill start assist function of the vehicle being in an open state, the minimum driving torque being the minimum torque for the vehicle to enter a running state from a stationary state;

[0162] A control unit 302 is configured to control the hill start assist function to exit in response to the exit condition of the hill start assist function being met;

[0163] A pressurizing unit 303 is configured to apply a target pressure to the wheels of the vehicle according to the relative size between the minimum driving torque and the maximum creep torque, wherein the vehicle is in a stationary state at the current slope value under the action of the target pressure;

[0164] A receiving unit 304 is configured to receive an actual driving torque curve from a vehicle control unit;

[0165] A pressure relief unit 305 is configured to reduce the target pressure to 0 within a time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, so as to control the vehicle to start after the actual driving torque reaches the minimum driving torque.

[0166] Optionally, the pressurizing unit 303 is specifically configured to:

[0167] In response to determining that the minimum driving torque is less than the maximum creep torque, the first pressure is taken as the target pressure, wherein the first pressure is the pressure required to maintain the vehicle stationary on the maximum creep slope corresponding to the maximum creep torque;

[0168] The first pressure is applied to the wheels.

[0169] Optionally, the pressurizing unit 303 is specifically configured to:

[0170] In response to determining that the minimum driving torque is greater than the maximum creep torque, a second pressure value corresponding to the current slope value is determined, the second pressure being the pressure required to maintain the vehicle stationary when there is a creep torque at the current slope value;

[0171] The second pressure is taken as a target pressure, and the second pressure is applied to the wheel.

[0172] Optionally, the pressure relief unit 305 comprises:

[0173] a reference time length determining sub-unit configured to determine a reference time length required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum creep slope according to the minimum driving torque corresponding to the maximum creep slope and the preset torque slope;

[0174] an actual time length determining sub-unit configured to determine a first actual time length required for the actual driving torque to increase to the minimum driving torque corresponding to the current slope value according to the reference time length, the current slope value and the maximum creep slope;

[0175] a pressure relief sub-unit configured to reduce the target pressure to 0 within the first actual time length.

[0176] Optionally, the pressure relief sub-unit is configured to:

[0177] determine an actual pressure relief slope according to the first actual time length and the target pressure;

[0178] reduce the target pressure to 0 within the first actual time length based on the actual pressure relief slope.

[0179] Optionally, the pressure relief unit 305 comprises:

[0180] a slope determining sub-unit configured to determine a first slope at which the driver-requested torque increases to the maximum creep torque;

[0181] an actual time length determining sub-unit configured to determine a second actual time length at which the actual driving torque increases from the maximum creep torque to the minimum driving torque based on the first slope;

[0182] a pressure relief sub-unit configured to reduce the target pressure to 0 within the second actual time length in response to determining that the actual driving torque increases to the maximum creep torque.

[0183] Optionally, the slope determining sub-unit is further configured to:

[0184] determine a real-time slope at which the driver-requested torque increases from the maximum creep torque to the minimum driving torque corresponding to the current slope;

[0185] the actual time length determining sub-unit is further configured to:

[0186] determine a corrected second actual time length according to the first slope, the real-time slope and the second actual time length;

[0187] the pressure relief sub-unit is specifically configured to:

[0188] In response to determining that the actual driving torque increases to the maximum creep torque, the target pressure is decreased to 0 in the second actual time length after the correction.

[0189] Optionally, the pressure relief subunit is specifically configured to:

[0190] In response to determining that the actual driving torque increases to the maximum creep torque, the actual pressure relief slope is determined according to the target pressure and the second actual time length after the correction.

[0191] The target pressure is decreased to 0 according to the actual pressure relief slope in the second actual time length after the correction.

[0192] Please refer to Figure 10 , based on the same inventive concept, the electronic stability control system provided in the embodiments of the present application includes at least one processor 401, and the processor 401 is configured to execute a computer program stored in a memory, so as to realize the flowchart of the control method of the ramp starting provided in the embodiments of the present application as shown in Figures 1-8 .

[0193] Optionally, the processor 401 can be a central processing unit, a specific ASIC, and can be one or more integrated circuits for controlling program execution.

[0194] Optionally, the electronic stability control system can further include a memory 402 connected with the at least one processor 401, and the memory 402 can include a ROM, a RAM and a disk memory. The memory 402 is used to store the data required by the processor 401 during operation, that is, the instructions executable by the at least one processor 401 are stored, and the at least one processor 401 executes the method as shown in Figures 1-8 by executing the instructions stored in the memory 402. Wherein, the number of memories 402 is one or more. Wherein, the number of memories 402 is one or more.

[0195] Please refer to Figure 11 , based on the same inventive concept, the vehicle provided in the embodiments of the present application includes the electronic stability control system as shown in Figure 10 . The vehicle can be a pure electric vehicle, a plug-in hybrid vehicle or a range extender vehicle, and the present application does not make special limitations here.

[0196] The embodiments of the present application further provide a computer storage medium, wherein the computer storage medium stores computer instructions, and when the computer instructions are run on a computer, the computer executes the method as shown in Figures 1-8 .

[0197] The above description is only the preferred embodiment of the present specification, and is not used to limit the present specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present specification shall be included in the protection scope of the present specification.

Claims

1. A control method for hill start, characterized by, The method comprises: determining a minimum drive torque at a current slope value in response to a hill start assist function of a vehicle being in an on state, the minimum drive torque being a minimum torque to bring the vehicle from a stationary state into a running state; controlling the hill start assist function to exit in response to an exit condition of the hill start assist function being met; applying a target pressure to wheels of the vehicle according to a relative size between the minimum drive torque and a maximum creep torque, wherein the vehicle is in a stationary state at the current slope value under the target pressure; receiving an actual drive torque curve from a vehicle control unit; lowering the target pressure to 0 within a time range in which an actual drive torque in the actual drive torque curve increases to the minimum drive torque, so that the actual drive torque controls the vehicle to start after the minimum drive torque is reached.

2. The method of claim 1, wherein, applying a target pressure to wheels of the vehicle according to a relative size between the minimum drive torque and a maximum creep torque, comprises: in response to determining that the minimum drive torque is less than the maximum creep torque, applying a first pressure as the target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep slope corresponding to the maximum creep torque; applying the first pressure to the wheels.

3. The method of claim 1, wherein, applying a target pressure to wheels of the vehicle according to a relative size between the minimum drive torque and a maximum creep torque, comprises: in response to determining that the minimum drive torque is greater than the maximum creep torque, determining a second pressure value corresponding to the current slope value; the second pressure being a pressure required to maintain the vehicle stationary when there is a creep torque at the current slope value; applying the second pressure to the wheels as the target pressure.

4. The method of claim 2, wherein, lowering the target pressure to 0 within a time range in which an actual drive torque in the actual drive torque curve increases to the minimum drive torque, comprises: determining a reference time length required for the actual drive torque to increase to the minimum drive torque corresponding to the maximum creep slope according to the minimum drive torque corresponding to the maximum creep slope and a preset torque slope; determining a first actual time length required for the actual drive torque to increase to the minimum drive torque corresponding to the current slope value according to the reference time length, the current slope value and the maximum creep slope; lowering the target pressure to 0 within the first actual time length.

5. The method of claim 4, wherein, lowering the target pressure to 0 within the actual time length, comprises: determining an actual pressure relief slope according to the first actual time length and the target pressure; lowering the target pressure to 0 based on the actual pressure relief slope within the first actual time length.

6. The method of claim 3, wherein, lowering the target pressure to 0 within a time range in which an actual drive torque in the actual drive torque curve increases to the minimum drive torque, comprises: determining a first slope at which a driver requested torque increases to the maximum creep torque; determining a second actual time length in which the actual drive torque increases from the maximum creep torque to the minimum drive torque based on the first slope; in response to determining that the actual drive torque increases to the maximum creep torque, decreasing the target pressure to 0 within the second actual time length.

7. The method of claim 6, wherein, Before decreasing the target pressure to 0 within the second actual time length, the method further comprises: determining a real-time slope of the driver-requested torque increasing from the maximum creep torque to a minimum drive torque corresponding to the current slope; determining a modified second actual time length according to the first slope, the real-time slope, and the second actual time length; in response to determining that the actual drive torque increases to the maximum creep torque, decreasing the target pressure to 0 within the second actual time length, comprises: in response to determining that the actual drive torque increases to the maximum creep torque, decreasing the target pressure to 0 within the modified second actual time length.

8. The method of claim 7, wherein, in response to determining that the actual drive torque increases to the maximum creep torque, decreasing the target pressure to 0 within the modified second actual time length, comprises: in response to determining that the actual drive torque increases to the maximum creep torque, determining an actual pressure relief slope according to the target pressure and the modified second actual time length; decreasing the target pressure to 0 within the modified second actual time length according to the actual pressure relief slope.

9. A control device for hill start assist, characterized by, The apparatus comprises: a determining unit configured to, in response to a hill start assist function of a vehicle being in an on state, determine a minimum drive torque at a current slope value, the minimum drive torque being a minimum torque for the vehicle to start from a static state; a control unit configured to, in response to a exit condition of the hill start assist function being met, control the hill start assist function to exit; a pressurizing unit configured to, according to a relative size between the minimum drive torque and a maximum creep torque, apply a target pressure to a wheel of the vehicle, wherein the vehicle is in a static state at the current slope value under the target pressure; a receiving unit configured to receive an actual drive torque curve from a vehicle control unit; a pressure relief unit configured to, within a time range in which an actual drive torque in the actual drive torque curve increases to the minimum drive torque, decrease the target pressure to 0, so that the actual drive torque controls the vehicle to start after the minimum drive torque is reached.

10. An electronic stability control system, characterized by The electronic stability control system comprises a memory for storing computer program instructions and a processor for executing the program instructions, wherein when the computer program instructions are executed by the processor, the electronic stability control system is triggered to perform the steps of the method according to any one of claims 1-8.

11. A vehicle characterized by comprising: The vehicle comprises an electronic stability control system according to claim 10. The vehicle comprises an electronic stability control system according to claim 10.

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