Hill starting control method, device and system and vehicle

Abstract

The embodiment of the invention provides a hill starting control method, device and system and a vehicle, relates to the technical field of vehicle control, and can perform pressure compensation on the vehicle with a crawling function during hill starting so as to prevent the vehicle from sliding during starting. And meanwhile, the pressure can be relieved at a proper time, so that the normal starting of the vehicle is ensured. The hill starting control method comprises the steps that in response to the situation that a hill starting auxiliary function of the vehicle is in an open state, the minimum driving torque under the current slope value is determined; responding to the exit condition of the hill starting auxiliary function, and controlling the hill starting auxiliary function to exit; according to the relative magnitude between the minimum driving torque and the maximum creeping torque, target pressure is applied to wheels of the vehicle; receiving an actual driving torque curve from a vehicle control unit; and within the time range when the actual driving torque is increased to the minimum driving torque, the target pressure is reduced to be 0, so that the vehicle is controlled to be started after the minimum driving torque is reached.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of vehicle control technology, and in particular to a control method, device, system and vehicle for hill start. Background Art

[0002] At present, for a vehicle with a creeping function, after temporarily parking on a slope and turning on the hill start assist function, if the driver wants to start on the slope, the following two problems may occur after the hill start assist function is exited: first, the creeping torque may be less than the minimum driving torque of the vehicle on the current slope, causing the vehicle to slip when starting; second, even if the creeping torque is greater than the minimum driving torque of the current slope, it takes a certain amount of time for the creeping torque to increase, so the vehicle may still slip when starting. Summary of the invention

[0003] The embodiments of the present application provide a control method, device, system and vehicle for hill starting, which can perform pressure compensation for a vehicle with a creeping function when starting on a hill, thereby preventing the vehicle from slipping during the starting process, and can also release pressure at an appropriate time to ensure normal starting of the vehicle.

[0004] In a first aspect, an embodiment of the present application provides a method for controlling a hill start, the method comprising: In response to a hill start assist function of the vehicle being in an on state, determining a minimum driving torque at a current slope value, the minimum driving torque being a minimum torque for enabling the vehicle to enter a driving state from a stationary state; In response to reaching an exit condition of the hill start assist function, controlling the hill start assist function to exit; applying a target pressure to the wheels of the vehicle according to the relative magnitude 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; Receive the actual driving torque curve from the vehicle controller; In the time range when the actual driving torque in the actual driving torque curve increases to the minimum driving torque, the target pressure is reduced to 0, so that the vehicle is controlled to start after the actual driving torque reaches the minimum driving torque.

[0005] In the embodiment of the present application, when the slope start assist function of the vehicle is turned on, the minimum driving torque required for starting on the current slope can be determined. Then, after the slope start assist function is exited, the pressure compensation of the vehicle's wheels can be performed according to the relative size between the above minimum driving torque and the maximum creep torque, so that the vehicle can be stationary on the current slope under the action of the pressure to avoid slipping. On this basis, in the process of the actual driving torque of the vehicle gradually increasing to the above minimum driving torque, the compensated pressure is gradually reduced to 0, that is, when the actual driving torque increases to the minimum driving torque, the compensated pressure is just reduced to 0, so that the vehicle can be controlled to start in time based on the above minimum driving torque, avoiding the starting delay problem caused by slow pressure release when the actual driving torque increases to the minimum driving torque, and also avoiding the slipping problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque.

[0006] Optionally, applying a target pressure to the wheels of the vehicle according to a relative magnitude between the minimum driving torque and the maximum creep torque comprises: In response to determining that the minimum driving torque is less than the maximum creep torque, taking a first pressure as the target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep gradient corresponding to the maximum creep torque; The first pressure is applied to the wheel.

[0007] In an embodiment of the present application, 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. Therefore, the pressure required to maintain the vehicle stationary at the maximum creep slope is used as the compensation pressure of the vehicle at the current slope, which can ensure that the vehicle will not slip.

[0008] Optionally, applying a target pressure to the wheels of the vehicle according to a relative magnitude between the minimum driving torque and the maximum creep torque comprises: In response to determining that the minimum driving torque is greater than the maximum creep torque, determining a second pressure value corresponding to the current slope value; the second pressure is a pressure required to maintain the vehicle at rest when creep torque exists at the current slope value; The second pressure is used as the target pressure, and the second pressure is applied to the wheel.

[0009] In an embodiment of the present application, if the minimum driving torque is greater than the maximum creep torque, it indicates that the current slope of the vehicle is already greater than the maximum creep slope corresponding to the maximum creep torque. Therefore, the pressure corresponding to the current slope can be determined based on the correspondence between the slope value greater than the maximum creep slope and the pressure required to maintain the vehicle stationary when the creep torque exists, and this pressure is used as the compensation pressure of the vehicle at the current slope, which can ensure that the vehicle will not slip.

[0010] Optionally, within a time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, reducing the target pressure to 0 includes: Determining a reference time 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; Determine a first actual time required for the actual driving torque to increase to a minimum driving torque corresponding to the current slope value according to the reference time, the current slope value and the maximum creep slope; The target pressure is reduced to 0 within the first actual time period.

[0011] In the embodiment of the present application, since the minimum driving torque corresponding to the maximum creep slope and the preset torque slope of the creep torque increase in the vehicle controller are both known, the benchmark time required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum creep slope can be determined. On this basis, since the current slope is smaller than the maximum creep slope, the minimum driving torque corresponding to the current slope must also be smaller than the minimum driving torque corresponding to the maximum creep slope, and thus the time for the creep torque to reach the minimum driving torque corresponding to the current slope must also be smaller than the time for the minimum driving torque to reach the maximum creep slope. Therefore, the actual time for the creep torque to reach the minimum driving torque corresponding to the current slope can be determined based on the benchmark time, the current slope and the maximum creep slope, and then the supplementary pressure is released within the actual time range, so that the vehicle can be controlled to start in time based on the minimum driving torque corresponding to the current slope, avoiding the starting 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 slipping problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0012] Optionally, reducing the target pressure to 0 within the actual time period includes: Determining an actual pressure relief slope according to the first actual duration and the target pressure; The target pressure is reduced to 0 based on the actual pressure relief slope within the first actual time period.

[0013] In the embodiment of the present application, an actual pressure relief slope can be determined based on the target pressure and the first actual duration, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the first actual duration, so as to avoid the problem of slipping caused by too fast pressure relief in the early stage of pressure relief when the target pressure is reached.

[0014] Optionally, within a time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, reducing the target pressure to 0 includes: determining a first slope at which the driver requested torque increases to the maximum creep torque; determining a second actual time duration for the actual driving torque to increase from the maximum creep torque to the minimum driving torque based on the first slope; In response to determining that the actual driving torque increases to the maximum creep torque, the target pressure is reduced to 0 within the second actual time period.

[0015] In the embodiment of the present application, when 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 controller will determine the driver's request torque according to the accelerator pedal opening. At this time, if the driver's request torque is less than the maximum creep torque, it can be considered that the vehicle controller will not respond to the driver's request torque, but will output based on the maximum creep torque, but the electronic stability control system can calculate the first slope of the driver's request torque from 0 to the maximum creep torque. When the driver's request torque exceeds the maximum creep torque, the creep torque will exit, and the vehicle controller will use the driver's request torque as the actual driving torque. Since the driver's request torque increases from 0 to the maximum creep torque based on the first slope, then after the driver's request torque is used as the actual driving torque, in theory, the driver's request torque increases from the maximum creep torque to the minimum driving torque, and should also increase based on the first slope. Therefore, the second actual duration of the driver's request torque from the maximum creep torque to the minimum driving torque can be determined based on the above first slope. After the driver's requested torque reaches the maximum creep torque, that is, after the additional driving force begins to be generated by pressing the accelerator pedal, the supplementary pressure is released within the above-mentioned second actual time range, so that the vehicle can be controlled to start in time based on the minimum driving torque corresponding to the current slope, avoiding the starting 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 slipping problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0016] Optionally, before reducing the target pressure to 0 within the second actual time period, the method further includes: determining a real-time slope of the driver request torque increasing from the maximum creep torque to a minimum drive torque corresponding to a current slope; Determine a corrected second actual duration according to the first slope, the real-time slope, and the second actual duration; 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 period comprises: 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 period.

[0017] In the embodiment of the present application, the first slope can be considered as the ideal slope of the driver's requested torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope, and the real-time slope can be considered as the actual slope of the driver's requested torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope. Then, based on the first slope, the real-time slope and the second actual duration, the corrected second actual duration that can be used for pressure relief can be determined, and then pressure relief is performed within the corrected second actual duration, thereby ensuring the accuracy of the pressure relief time range, avoiding the starting delay problem caused by late pressure release, and avoiding the slipping problem caused by early pressure release.

[0018] Optionally, 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 period comprises: In response to determining that the actual driving torque increases to the maximum creep torque, determining an actual pressure relief slope according to the target pressure and the corrected second actual time length; The target pressure is reduced to 0 according to the actual pressure relief slope within the corrected second actual time period.

[0019] In the embodiment of the present application, the actual pressure relief slope can be determined based on 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 slipping caused by too fast pressure relief in the early stage of pressure relief when the target pressure is reached.

[0020] In a second aspect, an embodiment of the present application provides a control device for hill start, the device comprising: a determination unit, configured to determine a minimum driving torque at a current slope value in response to a hill start assist function of the vehicle being in an on state, wherein the minimum driving torque is a minimum torque for enabling the vehicle to enter a driving state from a stationary state; a control unit, configured to control the exit of the hill start assist function in response to reaching an exit condition of the hill start assist function; a boost unit, configured to apply a target pressure to the wheels of the vehicle according to a relative magnitude 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; A receiving unit, used for receiving an actual driving torque curve from a vehicle controller; The pressure relief unit is used 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.

[0021] Optionally, the boost unit is specifically used for: In response to determining that the minimum driving torque is less than the maximum creep torque, taking a first pressure as the target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep gradient corresponding to the maximum creep torque; The first pressure is applied to the wheel.

[0022] Optionally, the boost unit is specifically used for: In response to determining that the minimum driving torque is greater than the maximum creep torque, determining a second pressure value corresponding to the current slope value; the second pressure is a pressure required to maintain the vehicle at rest when creep torque exists at the current slope value; The second pressure is set as the target pressure, and the second pressure is applied to the wheel.

[0023] Optionally, the pressure relief unit includes: a reference time determination subunit, configured to determine a reference time 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; an actual duration determination subunit, configured to determine, according to the reference duration, the current slope value and the maximum creep slope, a first actual duration required for the actual driving torque to increase to a minimum driving torque corresponding to the current slope value; The pressure relief subunit is used to reduce the target pressure to 0 within the first actual time period.

[0024] Optionally, the pressure relief subunit is used for: Determining an actual pressure relief slope according to the first actual duration and the target pressure; The target pressure is reduced to 0 based on the actual pressure relief slope within the first actual time period.

[0025] Optionally, the pressure relief unit includes: a slope determination subunit, for determining a first slope at which the driver's requested torque increases to the maximum creep torque; an actual duration determining subunit, configured to determine, based on the first slope, a second actual duration for the actual driving torque to increase from the maximum creep torque to the minimum driving torque; The pressure relief subunit is configured to reduce the target pressure to 0 within the second actual time period in response to determining that the actual driving torque increases to the maximum creep torque.

[0026] Optionally, the slope determination subunit is further used for: determining a real-time slope of the driver request torque increasing from the maximum creep torque to a minimum drive torque corresponding to a current slope; The actual duration determination subunit is further used for: Determine a corrected second actual duration according to the first slope, the real-time slope, and the second actual duration; The pressure relief subunit is specifically used for: 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 period.

[0027] Optionally, the pressure relief subunit is specifically used for: In response to determining that the actual driving torque increases to the maximum creep torque, determining an actual pressure relief slope according to the target pressure and the corrected second actual time length; The target pressure is reduced to 0 according to the actual pressure relief slope within the corrected second actual time period.

[0028] In a third aspect, an embodiment of the present application provides an electronic stability control system, which includes 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 execute the steps of the method described in any embodiment of the first aspect.

[0029] In a fourth aspect, an embodiment of the present application provides a vehicle, comprising the electronic stability control system in the embodiment of the third aspect.

[0030] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store computer instructions, and when the computer is running, the computer enables the computer to execute the steps of the method described in any embodiment of the first aspect.

[0031] It should be understood that the second to fifth aspects of the embodiments of the present application are consistent with the technical solutions of the first aspect of the embodiments of the present application, and the beneficial effects achieved by each aspect and the corresponding feasible implementation methods are similar and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic flow chart of a hill start control method provided in an embodiment of the present application; Figure 2 A schematic flow chart of a method for applying a target pressure to a wheel provided in an embodiment of the present application; Figure 3 A schematic flow chart of another method for applying target pressure to a wheel provided in an embodiment of the present application; Figure 4 A schematic diagram of a process for relieving target pressure provided in an embodiment of the present application; Figure 5 A schematic diagram of a pressure relief method provided in an embodiment of the present application; Figure 6 A schematic flow chart of another method for relieving target pressure provided in an embodiment of the present application; Figure 7 A schematic flow chart of another method for relieving target pressure provided in an embodiment of the present application; Figure 8 A schematic diagram of a pressure relief method provided in an embodiment of the present application; Fig. 9 A hill start control device provided in an embodiment of the present application; Fig.10 A schematic diagram of the structure of an electronic stability control system provided in an embodiment of the present application; Fig.11 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to better understand the technical solution of this specification, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] It should be clear that the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this specification.

[0036] 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 this specification. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0037] At present, new energy vehicles are generally equipped with creeping function. The creeping function means that when the vehicle is in the forward gear (D gear) or reverse gear (R gear), and the accelerator pedal and brake pedal are not pressed, the vehicle will move slowly at a certain speed. At the same time, a maximum creeping torque, that is, the maximum creeping torque, will be set to ensure that the vehicle can travel at a set speed at a certain slope (maximum creeping slope).

[0038] For a vehicle with a creep function, after temporarily parking on a slope and turning on the hill start assist function, if the driver wants to start on the slope, the following two problems may occur after the hill start assist function is exited: First, the creep torque may be less than the minimum driving torque of the vehicle on the current slope, causing the vehicle to slip when starting; second, even if the creep torque is greater than the minimum driving torque of the current slope, it takes a certain amount of time for the creep torque to increase, so the vehicle may still slip when starting.

[0039] In view of this, an embodiment of the present application provides a control method for hill starting, in which the electronic stability control system can compensate the vehicle for pressure based on the relative size between the minimum driving torque required for the vehicle to start on the current slope and the maximum creep torque that the vehicle can provide, so as to prevent the vehicle from slipping when starting; and in the process of the actual driving torque of the vehicle increasing to the minimum driving torque, the compensated pressure is gradually reduced until it is 0, so that the vehicle can be controlled to start in a timely manner based on the above-mentioned minimum driving torque.

[0040] The technical solution protected by the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0041] See also Figure 1 , a hill start control method provided in an embodiment of the present application is applied to an electronic stability control system (ESC). The process of the method is described as follows: Step 101: In response to a hill start assist function of the vehicle being in an on state, determining a minimum driving torque at a current slope value.

[0042] In an embodiment of the present application, when the driver stops the vehicle on the current slope 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 has released the brake pedal, and the hill start assist function will be triggered to turn on. When the hill start assist function is turned on, it can be considered that a braking force of a target duration is applied to the vehicle, so even if the driver releases the brake pedal, the vehicle can stop on the current slope within the target duration after the driver releases the brake pedal. At this time, the ESC can obtain the current slope value of the current slope, and then determine the minimum driving torque corresponding to the current slope value based on the pre-stored correspondence between the slope value and the minimum driving torque. It should be understood that the minimum driving torque here can be considered to be the minimum torque required to drive the vehicle to start (from rest to start driving) at the current slope value.

[0043] Step 102: In response to reaching an exit condition of the hill start assist function, controlling the hill start assist function to exit.

[0044] In the embodiment of the present application, the ESC starts timing when the brake pedal opening is less than a set threshold. If the timing reaches the preset time, it is considered that there is enough time for the vehicle to start after the brake pedal is released, so the hill start assist function can be controlled to exit.

[0045] Step 103: Apply target pressure to the wheels of the vehicle according to the relative magnitude between the minimum driving torque and the maximum creep torque.

[0046] In the embodiment of the present application, after the hill start assist function is exited, the braking force provided by the function naturally disappears. At this time, the ESC can determine the target pressure applied to the vehicle's brake master cylinder based on the relative size between the minimum driving torque corresponding to the current slope and the maximum creep torque of the vehicle's creep function. 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.

[0047] The following describes in detail the target pressure applied to the wheel in different situations.

[0048] Case 1: The minimum driving torque corresponding to the current slope is less than the maximum creep torque.

[0049] See also Figure 2 , is a flow chart of a method for applying a target pressure to a wheel provided in an embodiment of the present application. Step 103 can be implemented by executing sub-steps 1031 and 1032: Step 1031: In response to determining that the minimum driving torque is less than the maximum creep torque, taking a first pressure as a target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep gradient corresponding to the maximum creep torque.

[0050] Step 1032: Apply a first pressure to the wheel.

[0051] In an embodiment of the present application, 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. Therefore, the pressure required to maintain the vehicle stationary at the maximum creep slope is applied to the wheel end as the compensation pressure of the vehicle at the current slope, which can ensure that the vehicle will not slip under the action of the compensation pressure.

[0052] For example, the maximum creep torque is the creep torque that allows the vehicle to 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 keep the vehicle stationary on a 10% slope can be used as the target pressure.

[0053] Case 2: The minimum driving torque corresponding to the current slope is greater than the maximum creep torque.

[0054] See also Figure 3 , is a flow chart of another method for applying target pressure to a wheel provided in an embodiment of the present application. Step 103 can be implemented by executing sub-steps 1033 and 1034: Step 1033: In response to determining that the minimum driving torque is greater than the maximum creep torque, determine a second pressure value corresponding to the current slope value; the second pressure is the pressure required to maintain the vehicle at rest when the creep torque exists at the current slope value.

[0055] Step 1034: Taking the second pressure as the target pressure, and applying the second pressure to the wheel.

[0056] In an embodiment of the present application, if the minimum driving torque is greater than the maximum creep torque, it indicates that the current slope of the vehicle is already greater than the maximum creep slope corresponding to the maximum creep torque. Therefore, the pressure corresponding to the current slope can be determined based on the correspondence between the slope value greater than the maximum creep slope and the pressure required to maintain the vehicle stationary when the creep torque exists, and this pressure can be applied to the wheel end as the compensation pressure of the vehicle at the current slope, which can ensure that the vehicle will not slip under the simultaneous action of the creep torque and the compensation pressure.

[0057] For example, if the maximum creep slope is 10% and the minimum driving torque is greater than the maximum creep torque, it indicates that the current slope of the vehicle is greater than the maximum creep slope (10%). The ESC pre-establishes the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 15% slope value; the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 20% slope value; the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 25% slope value; and the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 30% slope value. If the current slope value is 15%, the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the current slope value is determined; if the current slope value is between 15% and 20%, the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 15% slope value and the pressure required to maintain the vehicle stationary when there is creep torque corresponding to the 20% slope value are calculated, and the pressure average is applied to the wheel end as the target pressure.

[0058] Step 104: Receive the actual driving torque curve from the vehicle controller.

[0059] In the embodiment of the present application, after the ESC applies the target pressure to the wheel end, it can ensure that the vehicle remains stationary on 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 for output. The actual driving torque here may be the creeping torque or the torque generated by the driver stepping on the accelerator pedal, which will be described in detail below. At the same time, the VCU also sends the actual driving torque curve formed by the actual driving torque to the ESC.

[0060] Step 105 : Within the time range from when the actual driving torque in the actual driving torque curve increases to the minimum driving torque, the target pressure is reduced to 0, so that the vehicle is controlled to start after the actual driving torque reaches the minimum driving torque.

[0061] In the embodiment of the present application, the ESC receives the actual driving torque curve from the VCU and can determine the time range for the actual driving torque to increase to the minimum driving torque from the actual driving torque curve, and then gradually reduces the target pressure to 0 within the time range, that is, when the actual driving torque increases to the minimum driving torque, the compensated target pressure is just reduced to 0, so that the vehicle can be controlled to start in time based on the above-mentioned minimum driving torque, avoiding the starting delay problem caused by slow pressure release when the actual driving torque increases to the minimum driving torque, and avoiding the slipping problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque.

[0062] The following is a detailed description of how to reduce the target pressure to 0 in different situations.

[0063] Case 1: When the minimum driving torque corresponding to the current slope is less than the maximum creep torque, the pressure relief begins when the actual driving torque tends to increase.

[0064] See also Figure 4 , is a flow chart of a method for relieving target pressure provided in an embodiment of the present application. Step 105 can be implemented by executing sub-steps 1051 to 1053: Step 1051: Determine a reference time 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.

[0065] Step 1052: Determine a first actual time required for the actual driving torque to increase to the minimum driving torque corresponding to the current slope value according to the reference time, the current slope value and the maximum creep slope.

[0066] In the embodiment of the present application, when the minimum driving torque corresponding to the current slope is less than the maximum creeping torque, the starting of the vehicle mainly depends on the creeping torque. Since the minimum driving torque corresponding to the maximum creeping slope and the preset torque slope of the creeping torque growth in the vehicle controller are both known, the ratio of the minimum driving torque corresponding to the maximum creeping slope to the preset torque slope can be calculated to determine the reference time required for the actual driving torque to increase to the minimum driving torque corresponding to the maximum creeping slope. On this basis, since the current slope is less than the maximum creeping slope, the time for the creeping torque to reach the minimum driving torque corresponding to the current slope must also be less than the time for the creeping torque to reach the minimum driving torque corresponding to the maximum creeping slope. Therefore, the first actual time for the creeping torque to reach the minimum driving torque corresponding to the current slope can be determined based on the reference time, the current slope and the maximum creeping slope. The calculation method of the first actual time is shown in formula (1): (1) Among them, t1 represents the first actual duration, t0 represents the reference duration, x represents the current slope, and x max Indicates the maximum creep slope.

[0067] It is worth noting that in the embodiment 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.

[0068] Step 1053: Reduce the target pressure to 0 within the first actual time period.

[0069] After calculating the first actual duration, if the ESC determines through the actual driving torque curve that the actual driving torque has an increasing trend, the supplemented first pressure is released 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, thereby avoiding the starting 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 slipping problem caused by too fast pressure release before the actual driving torque increases to the minimum driving torque of the current slope.

[0070] In some embodiments, considering that the VCU loads the creep torque based on a fixed preset torque slope, a fixed pressure relief slope can also be used for pressure relief during the pressure relief process in the embodiments of the present application to avoid the problem of slipping caused by too fast pressure relief in the early stage of pressure relief when the target pressure is reached.

[0071] See also Figure 5 , which is a flow chart of a pressure relief method provided in an embodiment of the present application. Step 1053 can be implemented by executing sub-steps 10531 to 10532: Step 10531: Determine the actual pressure relief slope according to the first actual duration and the target pressure.

[0072] Step 10532: Reduce the target pressure to 0 based on the actual pressure relief slope within the first actual time period.

[0073] In the embodiment of the present application, the actual pressure relief slope can be determined according to the target pressure and the first actual duration, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the first actual duration, so as to avoid the problem of slipping caused by the target pressure being relieved too quickly in the early stage of pressure relief and the creep torque increasing slowly. Of course, a pressure relief method of first slow and then fast can also be adopted, that is, the actual pressure relief slope can be first small and then large for pressure relief within the corrected second actual duration.

[0074] Case 2: When the minimum driving torque corresponding to the current slope is greater than the maximum creep torque, the pressure relief starts after the actual driving torque increases to the maximum creep torque.

[0075] See also Figure 6 , which is a flow chart of another method for relieving target pressure provided in an embodiment of the present application. Step 105 can be implemented by executing sub-steps 1054 to 1056: Step 1054: Determine a first slope at which the driver requested torque increases to the maximum creep torque.

[0076] Step 1055: Determine a second actual time duration for the actual driving torque to increase from the maximum creep torque to the minimum driving torque based on the first slope.

[0077] In the embodiment of the present application, when the minimum driving torque corresponding to the current ramp is greater than the maximum creep torque, the starting of the vehicle mainly depends on the creep torque and the driving force generated by the driver stepping on the driving pedal. After the user steps on the accelerator pedal, the vehicle controller will detect the accelerator pedal opening, and then determine the driver's request torque based on the accelerator pedal opening. At this time, if the driver's request torque is less than the maximum creep torque, the vehicle controller will not respond to the driver's request torque, but will output based on the maximum creep torque, but the vehicle controller will send the driver's request torque to the ESC. While receiving the driver's request torque from the VCU, the ESC will record the corresponding timestamp, and then the ESC can determine the first slope based on the maximum creep torque and the time for the driver's request torque to increase from 0 to the maximum creep torque. When the VCU determines that the driver's request torque exceeds the maximum creep torque, the VCU will control the creep torque to exit, and the vehicle controller will use the driver's request torque as the actual driving torque. Since when the driver steps on the accelerator pedal, the driver's requested torque increases from 0 to the maximum creep torque based on the first slope, then after the driver's requested torque is used as the actual driving torque, in theory, the driver's requested torque increases from the maximum creep torque to the minimum driving torque, and should also increase based on the first slope. Therefore, the second actual time for the driver's requested torque to increase from the maximum creep torque to the minimum driving torque can be determined based on the first slope.

[0078] Step 1056: In response to determining that the actual driving torque increases to the maximum creep torque, reducing the target pressure to 0 within a second actual time period.

[0079] In the embodiment of the present application, before the driver's request torque is greater than the maximum creep torque, although the driver has stepped on the accelerator pedal, no additional driving torque can be generated. At this time, the vehicle still depends on the combined effect of the creep torque and the applied target pressure to maintain the vehicle stationary. Therefore, before the driver's request torque is greater than the maximum creep torque, the target pressure cannot be released. Once the pressure is released, the vehicle will slip. After the driver's request torque is greater than the maximum creep torque, the creep torque is exited. The role played by the driver's request torque is equivalent to generating additional driving torque on the basis of the creep torque. Therefore, when the additional driving torque is generated, the target pressure can be gradually released within the second actual time, so that the vehicle can be controlled to start in time when the driver's request torque reaches the minimum driving torque corresponding to the current slope, avoiding the starting delay problem caused by slow pressure release when the driver's request torque increases to the minimum driving torque of the current slope, and avoiding the slipping problem caused by too fast pressure release before the driver's request torque increases to the minimum driving torque of the current slope.

[0080] In some embodiments, considering that the slope of the driver's requested torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope may be the same as or different from the slope of the driver's requested torque increasing from 0 to the maximum creep torque, in this embodiment of the present application, the second actual duration can be corrected using the slope of the driver's requested torque increasing from the maximum creep torque to the minimum driving torque on the basis of determining the second actual duration based on the first slope, thereby ensuring that the target pressure can be released more accurately.

[0081] See also Figure 7 , which is a flow chart of another method for relieving target pressure provided in an embodiment of the present application. Before executing step 1056, steps 1057 to 1058 may also be executed: Step 1057 : Determine the real-time slope of the driver's requested torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope.

[0082] Step 1058: Determine a corrected second actual duration according to the first slope, the real-time slope, and the second actual duration.

[0083] Step 1056 can be specifically implemented by executing sub-step 10561: 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 period.

[0084] In the embodiment of the present application, the first slope can be considered as the ideal slope of the driver's request torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope, and the real-time slope can be considered as the actual slope of the driver's request torque increasing from the maximum creep torque to the minimum driving torque corresponding to the current slope. Then, according to the first slope, the real-time slope and the second actual duration, the corrected second actual duration that can be used for pressure relief can be determined. The calculation formula of the corrected second actual duration is shown in formula (2): (2) in, represents the second actual duration after correction, t2 represents the second actual duration, k1 represents the first slope, and k2 represents the real-time slope. It should be understood that the larger k2 is, the The smaller it is, that is, the faster the driver's requested torque increases from the maximum creep torque to the minimum driving torque corresponding to the current slope, and accordingly, the pressure relief speed also needs to be faster.

[0085] After determining the corrected second actual duration, pressure relief can be performed within the corrected second actual duration, thereby ensuring the accuracy of the pressure relief time range, avoiding starting delays caused by late pressure release, and avoiding slipping problems caused by early pressure release.

[0086] In some embodiments, when the target pressure is released, the pressure release may be performed based on a fixed pressure release slope to avoid the problem of the vehicle slipping due to excessively fast pressure release in the early stage of the target pressure release.

[0087] See also Figure 8 , which is a flow chart of a pressure relief method provided in an embodiment of the present application. Step 10561 can be implemented by executing sub-steps 201 to 202: Step 201 : In response to determining that the actual driving torque increases to the maximum creep torque, an actual pressure relief slope is determined according to a target pressure and a corrected second actual time period.

[0088] Step 202: reducing the target pressure to 0 according to the actual pressure relief slope within the corrected second actual time period.

[0089] In the embodiment of the present application, the actual pressure relief slope can be determined according to the target pressure and the corrected second actual duration, and then the target pressure is uniformly relieved based on the determined actual pressure relief slope within the corrected second actual duration, so as to avoid the problem of slipping caused by excessive pressure relief in the early stage of the target pressure relief. Of course, a slow-first-fast-later pressure relief method can also be adopted, that is, the actual pressure relief slope can be small first and then large to relieve pressure within the corrected second actual duration.

[0090] See also Fig. 9 Based on the same inventive concept, an embodiment of the present application provides a control device for hill start, the device comprising: A determination unit 301 is configured to determine a minimum driving torque at a current slope value in response to a hill start assist function of the vehicle being in an on state, wherein the minimum driving torque is a minimum torque for enabling the vehicle to enter a driving state from a stationary state; A control unit 302, configured to control the exit of the hill start assist function in response to reaching an exit condition of the hill start assist function; A boost unit 303, configured to apply a target pressure to the wheels of the vehicle according to a relative magnitude 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 target pressure; A receiving unit 304 is used to receive an actual driving torque curve from a vehicle controller; The pressure relief unit 305 is used to reduce the target pressure to 0 within the time range from the actual driving torque in the actual driving torque curve increasing to the minimum driving torque, so as to control the vehicle to start after the actual driving torque reaches the minimum driving torque.

[0091] Optionally, the boost unit 303 is specifically used for: In response to determining that the minimum driving torque is less than the maximum creep torque, taking a first pressure as a target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep gradient corresponding to the maximum creep torque; Apply a first pressure to the wheel.

[0092] Optionally, the boost unit 303 is specifically used for: In response to determining that the minimum driving torque is greater than the maximum creep torque, determining a second pressure value corresponding to the current slope value; the second pressure is the pressure required to maintain the vehicle at rest when the creep torque exists at the current slope value; The second pressure is used as the target pressure, and the second pressure is applied to the wheel.

[0093] Optionally, the pressure relief unit 305 includes: A reference time determination subunit, for determining a reference time 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; an actual duration determination subunit, for determining a first actual duration required for the actual driving torque to increase to a minimum driving torque corresponding to the current slope value according to the reference duration, the current slope value and the maximum creep slope; The pressure relief subunit is used to reduce the target pressure to 0 within a first actual time period.

[0094] Optionally, the pressure relief subunit is used to: Determine an actual pressure relief slope according to the first actual duration and the target pressure; The target pressure is reduced to 0 based on the actual pressure relief slope within the first actual time period.

[0095] Optionally, the pressure relief unit 305 includes: a slope determination subunit, for determining a first slope at which the driver's requested torque increases to a maximum creep torque; an actual duration determining subunit, configured to determine, based on the first slope, a second actual duration for the actual driving torque to increase from the maximum creep torque to the minimum driving torque; The pressure relief subunit is configured to reduce the target pressure to 0 within a second actual time period in response to determining that the actual driving torque increases to the maximum creep torque.

[0096] Optionally, the slope determination subunit is further configured to: determining a real-time slope of the driver's requested torque increasing from a maximum creep torque to a minimum drive torque corresponding to a current grade; The actual duration determination subunit is also used to: Determine a corrected second actual duration according to the first slope, the real-time slope, and the second actual duration; The pressure relief subunit is specifically used for: 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 period.

[0097] Optionally, the pressure relief subunit is specifically used for: In response to determining that the actual driving torque increases to the maximum creep torque, determining an actual pressure relief slope according to the target pressure and the corrected second actual time length; The target pressure is reduced to 0 according to the actual pressure relief slope within the corrected second actual time period.

[0098] See also Fig.10 Based on the same inventive concept, an embodiment of the present application provides an electronic stability control system, the electronic stability control system includes at least one processor 401, the processor 401 is used to execute a computer program stored in a memory, and implement the embodiment of the present application as provided in Figure 1-8 The flowchart diagram steps of the hill start control method are shown.

[0099] Optionally, the processor 401 may specifically be a central processing unit, a specific ASIC, or one or more integrated circuits for controlling program execution.

[0100] Optionally, the electronic stability control system may further include a memory 402 connected to the at least one processor 401, and the memory 402 may include a ROM, a RAM, and a disk memory. The memory 402 is used to store data required by the processor 401 when it is running, that is, to store instructions that can be executed by the at least one processor 401. The at least one processor 401 executes the instructions stored in the memory 402 to execute the following steps: Figure 1-8 The method shown. Wherein, the number of memories 402 is one or more. Wherein, the number of memories 402 is one or more.

[0101] See also Fig.11 Based on the same inventive concept, the present application embodiment provides a vehicle, which includes Fig.10 The electronic stability control system shown in the figure can be a pure electric vehicle, a plug-in hybrid vehicle, or an extended-range vehicle, and this application does not impose any special restrictions on this.

[0102] The present application also provides a computer storage medium, wherein the computer storage medium stores computer instructions, and when the computer instructions are executed on a computer, the computer executes Figure 1-8 method.

[0103] The above description is only a preferred embodiment of this specification and is not intended to limit this specification. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this specification should be included in the scope of protection of this specification.

Claims

1. A control method for starting on a hill, characterized in that: The method comprises: In response to a hill start assist function of the vehicle being in an on state, determining a minimum driving torque at a current slope value, the minimum driving torque being a minimum torque for enabling the vehicle to enter a driving state from a stationary state; In response to reaching an exit condition of the hill start assist function, controlling the hill start assist function to exit; applying a target pressure to the wheels of the vehicle according to a relative magnitude 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; Receive the actual driving torque curve from the vehicle controller; Within a time range when the actual driving torque in the actual driving torque curve increases to the minimum driving torque, the target pressure is reduced to 0, so that the vehicle is controlled to start after the actual driving torque reaches the minimum driving torque.

2. The method according to claim 1, characterized in that Applying a target pressure to the wheels of the vehicle according to a relative magnitude between the minimum driving torque and the maximum creep torque comprises: In response to determining that the minimum driving torque is less than the maximum creep torque, taking a first pressure as the target pressure, wherein the first pressure is a pressure required to maintain the vehicle stationary on a maximum creep gradient corresponding to the maximum creep torque; The first pressure is applied to the wheel.

3. The method according to claim 1, characterized in that Applying a target pressure to the wheels of the vehicle according to a relative magnitude between the minimum driving torque and the maximum creep torque comprises: In response to determining that the minimum driving torque is greater than the maximum creep torque, determining a second pressure value corresponding to the current slope value; the second pressure is a pressure required to maintain the vehicle at rest when creep torque exists at the current slope value; The second pressure is used as the target pressure, and the second pressure is applied to the wheel.

4. The method according to claim 2, characterized in that: In the time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, reducing the target pressure to 0 comprises: determining a reference time 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; Determine a first actual time required for the actual driving torque to increase to a minimum driving torque corresponding to the current slope value according to the reference time, the current slope value and the maximum creep slope; The target pressure is reduced to 0 within the first actual time period.

5. The method according to claim 4, characterized in that Reducing the target pressure to 0 within the actual time period includes: Determining an actual pressure relief slope according to the first actual duration and the target pressure; The target pressure is reduced to 0 based on the actual pressure relief slope within the first actual time period.

6. The method according to claim 3, characterized in that In the time range in which the actual driving torque in the actual driving torque curve increases to the minimum driving torque, reducing the target pressure to 0 comprises: determining a first slope at which the driver requested torque increases to the maximum creep torque; determining a second actual time duration for the actual driving torque to increase from the maximum creep torque to the minimum driving torque based on the first slope; In response to determining that the actual driving torque increases to the maximum creep torque, the target pressure is reduced to 0 within the second actual time period.

7. The method according to claim 6, characterized in that Before reducing the target pressure to 0 within the second actual time period, the method further includes: determining a real-time slope of the driver request torque increasing from the maximum creep torque to a minimum drive torque corresponding to a current slope; Determine a corrected second actual duration according to the first slope, the real-time slope, and the second actual duration; 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 period comprises: 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 period.

8. The method according to claim 7, characterized in that 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 period, comprises: In response to determining that the actual driving torque increases to the maximum creep torque, determining an actual pressure relief slope according to the target pressure and the corrected second actual time length; The target pressure is reduced to 0 according to the actual pressure relief slope within the corrected second actual time period.

9. A hill start control device, characterized in that: The device comprises: a determination unit, configured to determine a minimum driving torque at a current slope value in response to a hill start assist function of the vehicle being in an on state, wherein the minimum driving torque is a minimum torque for enabling the vehicle to enter a driving state from a stationary state; a control unit, configured to control the exit of the hill start assist function in response to reaching an exit condition of the hill start assist function; a boost unit, configured to apply a target pressure to the wheels of the vehicle according to a relative magnitude 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; A receiving unit, used for receiving an actual driving torque curve from a vehicle controller; The pressure relief unit is used 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.

10. An electronic stability control system, characterized in that: 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 execute the steps of the method according to any one of claims 1 to 8.

11. A vehicle, characterized in that: The vehicle comprises an electronic stability control system as claimed in claim 10.

Images