A method, device, system and vehicle for controlling four-wheel drive vehicle hill holding

Abstract

The application provides a four-wheel drive vehicle hill holding control method, device, system and vehicle, and belongs to the technical field of automobiles. When it is determined that the vehicle is in a hill holding braking state, the current parameters of the vehicle are acquired, it is judged whether the vehicle is in a vehicle easy to slide condition, when it is determined that the vehicle is in the vehicle easy to slide condition, the current drive mode is switched to a high-speed four-wheel drive mode or a low-speed drive mode with stronger braking force by controlling a transfer mode switch, so that automatic switching of the drive mode is realized without changing the braking system, the friction between the tire and the ground is increased when the vehicle is on a hill, the risk of sliding down the hill is effectively reduced, and the problem that when the four-wheel drive vehicle is in a high-speed two-wheel drive mode and is parked on a road with a certain slope, only the EPB or the hand brake is used to brake the rear wheels, and the vehicle has a risk of sliding down the hill is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile technology, in particular to a four-wheel drive vehicle hill holding control method, device, system and vehicle. BACKGROUND

[0002] The transfer case is an important component of the power system of the four-wheel drive vehicle, and its main function is to distribute the power output by the power system to the front and rear drive shafts to realize four-wheel drive of the vehicle. The transfer case usually includes a high-speed drive mode and a low-speed drive mode, wherein the high-speed drive mode includes a high-speed four-wheel drive mode and a high-speed two-wheel drive mode, and the low-speed drive mode includes a low-speed four-wheel drive mode.

[0003] In daily use, the four-wheel drive vehicle is mostly used in the high-speed two-wheel drive mode. When the vehicle is in the high-speed two-wheel drive mode and parked on a road surface with a certain slope, only using the EPB (Electrical Park Brake) or hand brake to brake the rear wheels, the vehicle has a risk of rolling down the slope. SUMMARY

[0004] The present application provides a four-wheel drive vehicle hill holding control method, device, system and vehicle to solve the problem that when the four-wheel drive vehicle is in the high-speed two-wheel drive mode and parked on a road surface with a certain slope, only using the EPB or hand brake to brake the rear wheels, the vehicle has a risk of rolling down the slope.

[0005] To solve the above problems, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a vehicle drift control method, which comprises:

[0007] When it is determined that the vehicle is in a parked brake state, acquiring a current parameter of the vehicle;

[0008] According to the current parameter, determining whether the vehicle is in a vehicle easy to roll condition;

[0009] When it is determined that the vehicle is in the vehicle easy to roll condition, controlling the transfer case mode switch to switch the current drive mode to the high-speed four-wheel drive mode or the low-speed drive mode.

[0010] In an embodiment of the present application, the current parameter includes the engine state of the vehicle, the current drive mode of the transfer case, the gear position of the transmission, the slope of the parked position and the rolling speed of the vehicle.

[0011] When it is determined that the vehicle is in the vehicle easy to roll condition, controlling the transfer case mode switch to switch the current drive mode to the high-speed four-wheel drive mode or the low-speed drive mode, comprising:

[0012] In the case that the engine is in the off state, when the current drive mode is in the high-speed two-drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, it is determined that the vehicle is in the easy-to-slip vehicle condition, and the transfer mode switch is controlled to switch the high-speed two-drive mode to the high-speed four-drive mode or the low-speed drive mode.

[0013] In the case that the engine is in the off state, when the current drive mode is in the high-speed two-drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, it is determined that the vehicle is in the easy-to-slip vehicle condition, and the transfer mode switch is controlled to switch the high-speed two-drive mode to the high-speed four-drive mode or the low-speed drive mode.

[0014] In an embodiment of the present application, when the current drive mode is in the high-speed two-drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, it is determined that the vehicle is in the easy-to-slip vehicle condition, and the transfer mode switch is controlled to switch the high-speed two-drive mode to the high-speed four-drive mode or the low-speed drive mode, the method further comprises:

[0015] After the vehicle is powered on, it is determined whether the engine is restarted;

[0016] After it is determined that the engine is restarted, the current vehicle is prompted to be in the high-speed four-drive mode or the low-speed drive mode through an instrument unit.

[0017] In an embodiment of the present application, when the current drive mode is in the high-speed two-drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, it is determined that the vehicle is in the easy-to-slip vehicle condition, and the transfer mode switch is controlled to switch the high-speed two-drive mode to the high-speed four-drive mode or the low-speed drive mode, comprising:

[0018] When the current drive mode is in the high-speed two-drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the slip speed is greater than the speed threshold, it is determined whether a brake pedal trigger signal is received within a preset time;

[0019] When the brake pedal trigger signal is not received within the preset time, the transfer mode switch is controlled to switch the high-speed two-drive mode to the high-speed four-drive mode or the low-speed drive mode, and the current vehicle is prompted to be in the high-speed four-drive mode or the low-speed drive mode through the instrument unit.

[0020] In an embodiment of the present application, when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the vehicle speed is greater than the vehicle speed threshold value, the method further comprises:

[0021] The instrument unit performs a slope sliding warning to remind the driver to brake.

[0022] In an embodiment of the present application, the method further comprises:

[0023] When it is determined that the vehicle is in the state of the parking brake, current weather information is obtained.

[0024] When the current weather information is easy-to-slide weather and the current driving mode is in the high-speed two-wheel drive mode, it is determined that the vehicle is in the easy-to-slide working condition, and the transfer mode switch is controlled to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0025] In a second aspect, based on the same inventive concept, embodiments of the present application provide a four-wheel drive vehicle hill holding control device, the device comprising:

[0026] The acquisition module is configured to, when it is determined that the vehicle is in the state of the parking brake, obtain current parameters of the vehicle.

[0027] The determination module is configured to determine whether the vehicle is in the easy-to-slide working condition according to the current parameters.

[0028] The switching module is configured to, when it is determined that the vehicle is in the easy-to-slide working condition, control the transfer mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0029] In an embodiment of the present application, the switching module comprises:

[0030] The first switching submodule is configured to, when the engine is in the off state and the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold value, determine that the vehicle is in the easy-to-slide working condition, and control the transfer mode switch to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0031] The second switching submodule is configured to, when the engine is in the on state, the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the slope sliding speed is greater than the vehicle speed threshold value, determine that the vehicle is in the easy-to-slide working condition, and control the transfer mode switch to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0032] In an embodiment of the present application, the second switching submodule comprises:

[0033] The judging submodule is configured to judge whether a brake pedal triggered signal is received within a preset time when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the coasting vehicle speed is greater than the vehicle speed threshold.

[0034] The switching submodule is configured to control the transfer case mode switch to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode and prompt the current vehicle to be in the high-speed four-wheel drive mode or the low-speed drive mode through the instrument unit when the brake pedal triggered signal is not received within the preset time.

[0035] In an embodiment of the present application, the second switching submodule further comprises:

[0036] The warning submodule is configured to perform a slope coasting warning through the instrument unit to remind the driver to perform a brake operation when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the coasting vehicle speed is greater than the vehicle speed threshold after the above conditions are met and before the judgment of whether the brake pedal triggered signal is received.

[0037] In an embodiment of the present application, the device further comprises:

[0038] The second judging module is configured to judge whether the engine is restarted after the vehicle is powered on.

[0039] The prompting module is configured to prompt the current vehicle to be in the high-speed four-wheel drive mode or the low-speed drive mode through the instrument unit after it is determined that the engine is restarted.

[0040] In an embodiment of the present application, the four-wheel drive vehicle hill hold control device further comprises:

[0041] The weather acquisition module is configured to acquire current weather information when it is determined that the vehicle is in a hill hold brake state.

[0042] The second switching module is configured to determine that the vehicle is in a vehicle easy to coast condition when the current weather information is easy-to-coast weather and the current driving mode is in the high-speed two-wheel drive mode, and control the transfer case mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed drive mode.

[0043] In a third aspect, the embodiments of the present application provide a four-wheel drive vehicle hill hold control system, which comprises:

[0044] The system further comprises a transfer control unit, a transfer mode switch and a parameter acquisition device connected to the transfer control unit, wherein

[0045] The transfer mode switch is configured to switch a driving mode of the transfer and to transmit the current driving mode to the transfer control unit, wherein the driving mode comprises a high-speed two-wheel drive mode, a high-speed four-wheel drive mode and a low-speed drive mode.

[0046] The parameter acquisition device is configured to acquire a current parameter of the vehicle and transmit the current parameter to the transfer control unit.

[0047] The transfer control unit is configured to receive the current parameter of the vehicle and execute the four-wheel drive vehicle hill-hold control method as proposed in the first aspect of the present application to control the transfer mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed drive mode when it is determined that the vehicle is in a hill-starting condition.

[0048] In an embodiment of the present application, the parameter acquisition device comprises:

[0049] A vehicle body electronic stability system, a transmission control unit and an engine control unit connected to the transfer control unit, wherein:

[0050] The vehicle body electronic stability system is configured to acquire slope information and hill-starting speed of a hill where the vehicle is parked and transmit the slope information and the hill-starting speed to the transfer control unit.

[0051] The transmission control unit is configured to acquire a transmission gear of the vehicle and transmit the transmission gear to the transfer control unit.

[0052] The engine control unit is configured to acquire an engine state of the vehicle and transmit the engine state to the transfer control unit.

[0053] In an embodiment of the present application, the system further comprises:

[0054] An instrument unit and a weather acquisition unit connected to the transfer control unit, wherein:

[0055] The weather acquisition unit is configured to acquire weather information and transmit the weather information to the transfer control unit.

[0056] The transfer control unit is configured to receive the weather information, and send an instruction to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to the transfer mode switch when the current drive mode is in the high-speed two-wheel drive mode and the current weather information is the easy-to-roll weather, and switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode when the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, and send a prompt instruction to the instrument unit when the engine is restarted after the high-speed two-wheel drive mode is switched to the high-speed four-wheel drive mode or the low-speed drive mode; and send a roll-off warning instruction to the instrument unit when the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the roll-off speed is greater than the speed threshold, and before determining whether the brake pedal is triggered.

[0057] The instrument unit is configured to receive the prompt instruction, and prompt a prompt operation according to the prompt instruction to prompt that the current vehicle is in the high-speed four-wheel drive mode, and receive the roll-off warning instruction, and perform a warning operation according to the roll-off warning instruction to remind the driver to perform a brake operation.

[0058] In a fourth aspect, the embodiments of the present application provide a vehicle, which at least comprises the four-wheel drive vehicle hill hold control system provided in the third aspect of the present application.

[0059] Compared with the prior art, the present application has the following advantages:

[0060] When it is determined that the vehicle is in the hill hold brake state, the embodiments of the present application acquire the current parameters of the vehicle, determine whether the vehicle is in the easy-to-roll working condition, switch the current drive mode to the high-speed four-wheel drive mode or the low-speed drive mode with stronger braking force when it is determined that the vehicle is in the easy-to-roll working condition, thereby realizing automatic switching of the drive mode without changing the braking system, increasing the friction between the tire and the ground when the vehicle is on the hill, and effectively reducing the risk of rolling down the hill. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. 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.

[0062] Figure 1 is a step flow chart of a four-wheel drive vehicle hill hold control method in the embodiments of the present application;

[0063] Figure 2 is a functional module schematic diagram of a four-wheel drive vehicle hill holding control device in an embodiment of the present application;

[0064] Figure 3 is a connection relationship schematic diagram of a four-wheel drive vehicle hill holding control system in an embodiment of the present application;

[0065] Figure 4 is a structure schematic diagram of a vehicle in an embodiment of the present application.

[0066] Fig. 200-four-wheel drive vehicle hill holding control device; 201-obtaining module; 202-judging module; 203-switching module; 300-four-wheel drive vehicle hill holding control system; 301-differential control unit; 302-vehicle body electronic stability system; 303-transmission control unit; 304-engine control unit; 305-differential mode switch; 306-instrument unit; 307-weather obtaining unit. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0068] In view of the technical problems proposed in the background art of the present application, the embodiments of the present application propose a four-wheel drive vehicle hill holding control method, which aims to automatically switch the driving mode without changing the brake system, by detecting the current parameters of the vehicle in real time when the vehicle is hill holding, when the current parameters are in a state in which the vehicle is prone to hill rolling, the driving mode can be automatically switched from the high-speed two-wheel drive mode with weak brake force to the high-speed four-wheel drive mode or the low-speed driving mode with stronger brake force, so as to increase the friction between the tire and the ground and effectively reduce the risk of hill rolling.

[0069] Referring to Figure 1 , a four-wheel drive vehicle hill holding control method is shown, which can include the following steps:

[0070] Step S101, when it is determined that the vehicle is in the hill holding brake state, obtaining the current parameters of the vehicle.

[0071] It needs to be explained in this embodiment that the current parameters include the engine state of the vehicle, the current driving mode of the differential, the transmission gear, the slope of the parking position and the hill rolling speed, wherein the driving mode includes the high-speed two-wheel drive mode, the high-speed four-wheel drive mode and the low-speed driving mode, and the hill rolling speed refers to the front wheel speed.

[0072] It needs to be further explained that the transfer usually includes a high-speed driving mode and a low-speed driving mode, the high-speed driving mode includes a high-speed four-wheel drive mode (hereinafter referred to as 4H mode) and a high-speed two-wheel drive mode (hereinafter referred to as 2H mode), and the low-speed driving mode includes a low-speed four-wheel drive mode (hereinafter referred to as 4L mode). When the transfer is in the 4H mode, the transfer rigidly locks the front and rear output shafts and outputs torque at 1:1, so that the vehicle can smoothly travel on complex road conditions such as mud and sand, and the power stability of the vehicle is improved. When the transfer is in the 4L mode, the transfer also rigidly locks the front and rear output shafts and amplifies the output torque of the transmission by more than 2.5 times. In the case that the vehicle is stuck in mud and cannot travel, the 4L mode is usually used for escape. When the vehicle travels on a relatively smooth road, the transfer can be in the 2H mode, so that the vehicle has a high speed. Therefore, when the vehicle is parked on a slope, the transfer is in the lock mode in the 4H mode and the 4L mode, and the front wheels can be inhibited from rolling, so the vehicle braking force in the 4H mode and the 4L mode is obviously stronger than that in the 2H mode.

[0073] In step S102, it is judged whether the vehicle is in the easy-to-slip condition according to the current parameters.

[0074] In the embodiment, considering that the four-wheel drive vehicle in the 2H mode has a risk of slipping on a slope when only using the EPB or the hand brake to brake the rear wheels, the current parameters of the vehicle, including the engine state of the vehicle, the current driving mode of the transfer, the gear of the transmission, the slope of the parking position, and the slipping speed, are combined to accurately determine whether the vehicle is in the easy-to-slip condition.

[0075] In step S103, when it is determined that the vehicle is in the easy-to-slip condition, the current driving mode is switched to the high-speed four-wheel drive mode or the low-speed driving mode by controlling the transfer mode switch.

[0076] In the embodiment, when it is determined that the vehicle is in the easy-to-slip condition, the current driving mode is switched to the high-speed four-wheel drive mode or the low-speed driving mode with stronger braking force by controlling the transfer mode switch, so that the automatic switching of the driving mode can be realized without changing the braking system, the friction between the tire and the ground is increased when parking on a slope, and the risk of slipping is effectively reduced.

[0077] In a possible implementation, step S103 can include the following specific steps:

[0078] Step S103-1, when the engine is in the off state, if the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold value, it is determined that the vehicle is in the easy-to-roll condition, and the control of the transfer mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode.

[0079] In the embodiment, the driving intention of the driver can be known by judging whether the transmission gear is in the N / P gear. When the transmission gear is in the D gear, it means that the driver only temporarily stops and does not need to switch the driving mode. When the transmission gear is in the N / P gear, it means that the driver has left the vehicle or needs to stay on the slope for a long time. At this time, if the current driving mode is in the high-speed two-wheel drive mode and the slope where the vehicle stays is greater than the slope threshold value, the vehicle will have a risk of rolling down the slope. When the above three conditions are met, the control of the transfer mode switch 305 automatically switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode, which increases the friction between the tires and the ground and effectively reduces the risk of rolling down the slope.

[0080] In the embodiment, the transfer mode switch 305 can be physical or virtual. When it is a virtual button, the transfer mode switch 305 can be arranged on the vehicle display screen or in a position suitable for the driver to control, such as the steering wheel. The embodiment does not make specific limitations on the form and position of the transfer mode switch 305.

[0081] In the embodiment, preferably, the slope threshold value can be set to 30%.

[0082] In one example, a driver drives a four-wheel drive vehicle in the high-speed two-wheel drive mode for off-road driving and needs to park on a slope with a slope of 35% to perform path exploration, vehicle chassis confirmation, or maintenance operations. The driver pulls up the EPB switch, sets the transmission gear to the N / P gear, and turns off the engine before getting off the vehicle. At this time, the embodiment can obtain the slope of the current vehicle parking position of the vehicle through the ESP (Electronic Stability Program). After determining that the current slope is greater than 30%, the control of the transfer mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to increase the friction between the tires and the ground and prevent the vehicle from rolling down the slope.

[0083] Step S103-2, in the case where the engine is in the un-off state, the current rolling speed of the vehicle is obtained. When the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the rolling speed is greater than the speed threshold value, it is determined that the vehicle is in the easy-to-roll condition, and the control of the transfer mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode.

[0084] In the embodiment, when it is determined that the vehicle is in the state of hill hold braking, it is considered that there is a risk of rolling even if the driver is in the vehicle when the engine is in the un-ignition state. Therefore, the embodiment can obtain the current rolling speed of the vehicle by the ESP, and when the rolling speed is greater than the vehicle speed threshold, it indicates that the vehicle has a rolling trend. If at this time, the vehicle also meets the conditions that the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold, the control differential mode switch 305 automatically switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to increase the friction between the tire and the ground and prevent the vehicle from rolling.

[0085] In the embodiment, preferably, the vehicle speed threshold can be set to 1 km / h.

[0086] In one example, a driver drives a four-wheel drive vehicle in the high-speed two-wheel drive mode for off-road driving, needs to park on a slope with a slope of 35% for temporary parking, or a companion gets off the vehicle to drive and the driver waits in the vehicle. At this time, the driver pulls up the EPB switch and the transmission gear is in the N / P gear. Since the vehicle only stays for a short time and the driver is in the cab, the engine is usually in the un-ignition state. At this time, if the vehicle has a rolling trend, the embodiment can obtain the current rolling speed of the vehicle and the slope of the vehicle hill-hold position by the ESP. When it is determined that the current slope is greater than 30% and the current rolling speed is greater than 1 km / h, the control differential mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to increase the friction between the tire and the ground and prevent the vehicle from rolling.

[0087] The embodiment can automatically switch the driving mode without changing the braking system by detecting the current parameters of the vehicle in real time when the vehicle is hill-hold. When the current parameters are in a state where the vehicle is prone to rolling, the high-speed two-wheel drive mode with weak braking force is automatically switched to the high-speed four-wheel drive mode or the low-speed drive mode with stronger braking force to increase the friction between the tire and the ground and effectively reduce the risk of rolling.

[0088] In a feasible embodiment, the specific steps of step S103-2 can be:

[0089] Step S103-2-1, when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the rolling speed is greater than the vehicle speed threshold, it is determined whether the brake pedal trigger signal is received within a preset time.

[0090] Step S103-2-2, when the brake pedal triggered signal is not received within the preset time, the control of the transfer case mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode, and prompts the current vehicle to be in the high-speed four-wheel drive mode through the instrument unit 306.

[0091] In the embodiment, considering the case that the driver actively brakes when the vehicle has a tendency to roll, the drive mode switching is not required, therefore, whether the driver has performed the brake operation is judged by detecting whether the brake pedal is triggered, and on this basis, different brake strategies can be taken according to different situations by setting a time threshold. Specifically, when the brake pedal triggered signal is received within the time threshold, it means that the driver has performed the brake operation, and at this time, the drive mode switching is not required; when the brake pedal triggered signal is not received within the time threshold, i.e. when the driver does not have time to perform the brake operation, the control of the transfer case mode switch 305 switches the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode, so as to timely stop the vehicle from rolling on the slope and ensure the safety of the vehicle.

[0092] In the embodiment, preferably, the preset time can be set to 2 seconds.

[0093] In a feasible embodiment, after step S103-1, the hill hold control method for the four-wheel drive vehicle can further include the following steps:

[0094] Step S104, after the vehicle is powered on, whether the engine is restarted is judged.

[0095] Step S105, after it is determined that the engine is restarted, it is prompted through the instrument unit 306 that the current vehicle is in the high-speed four-wheel drive mode or the low-speed drive mode.

[0096] In the embodiment, the driver is prompted by the instrument unit 306 that the vehicle has completed the drive mode switching, so that the driver can select the corresponding drive mode according to the actual road conditions in the subsequent driving. This avoids the driver not knowing that the current mode has been switched, so that the vehicle runs in the wrong drive mode, and reduces the driving experience of the driver.

[0097] In a feasible embodiment, when the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold, and the rolling speed is greater than the vehicle speed threshold, the hill hold control method for the four-wheel drive vehicle can further include the following steps before judging whether the brake pedal triggered signal is received:

[0098] Step S106, a rolling warning is performed through the instrument unit 306 to remind the driver to perform the brake operation.

[0099] In the embodiment, the slope slipping warning can be but not limited to displaying a warning word "vehicle has a tendency of slope slipping, please step on the brake pedal" on the display screen in the instrument unit 306, and / or taking measures such as sound and light alarm.

[0100] In a feasible embodiment, the slope parking control method of the four-wheel drive vehicle can further include the following steps:

[0101] In step S107, when it is determined that the vehicle is in the state of the hill hold brake, current weather information is acquired.

[0102] In step S108, when the two conditions that the current weather information is the easy slope slipping weather and the current driving mode is the high-speed two-wheel drive mode are met simultaneously, the transfer case mode switch 305 is controlled to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0103] It should be noted that the easy slope slipping weather refers to the weather that can easily cause the road to be wet and slippery, such as rainy, snowy or hailing weather.

[0104] In an example, a driver drives a four-wheel drive vehicle in the high-speed two-wheel drive mode for off-road driving, suddenly encounters heavy rain and needs to temporarily stop, and the driver pulls up the EPB switch for hill hold. At this time, the current weather condition of the vehicle in the local area can be acquired through the multimedia function of the vehicle, and the current driving mode is the high-speed two-wheel drive mode, so the automatic switching of the driving mode is performed, the transfer case mode switch 305 is controlled to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed driving mode, the adhesion of the vehicle is increased, and the slope slipping risk is reduced.

[0105] In the embodiment, the current weather condition of the vehicle in the local area can be acquired through the multimedia function of the vehicle, and in the easy slope slipping weather such as rainy and snowy weather, the automatic switching of the driving mode is performed only when the current driving mode is the high-speed two-wheel drive mode, the adhesion of the vehicle is increased, and the slope slipping risk is reduced.

[0106] Based on the same inventive concept, referring to Figure 2 An embodiment of the present application provides a slope parking control device 200 of a four-wheel drive vehicle, which comprises:

[0107] The acquisition module 201 is configured to acquire current parameters of the vehicle when it is determined that the vehicle is in the state of the hill hold brake.

[0108] The judgment module 202 is configured to judge whether the vehicle is in the easy slope slipping working condition according to the current parameters.

[0109] The switching module 203 is configured to control the transfer case mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed driving mode when it is determined that the vehicle is in the easy slope slipping working condition.

[0110] In an embodiment, the switching module 203 comprises:

[0111] a first switching submodule, configured to determine that the vehicle is in the easy-to-roll condition when the engine is in the off state, the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold value, and control the transfer mode switch to switch from the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode;

[0112] a second switching submodule, configured to determine that the vehicle is in the easy-to-roll condition when the engine is in the un-off state, the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the rolling speed is greater than the speed threshold value, and control the transfer mode switch to switch from the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode.

[0113] In an embodiment, the second switching submodule comprises:

[0114] a judging submodule, configured to judge whether a brake pedal triggered signal is received within a preset time when the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the rolling speed is greater than the speed threshold value.

[0115] a switching submodule, configured to control the transfer mode switch to switch from the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode when the brake pedal triggered signal is not received within the preset time, and prompt the current vehicle to be in the high-speed four-wheel drive mode or the low-speed drive mode through the instrument unit.

[0116] In an embodiment, the second switching submodule further comprises:

[0117] a warning submodule, configured to perform a rolling slope warning through the instrument unit to remind the driver to perform a braking operation after the current drive mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the rolling speed is greater than the speed threshold value, and before judging whether the brake pedal triggered signal is received.

[0118] In an embodiment, the four-wheel drive vehicle hill hold control device 200 further comprises:

[0119] a second judging module, configured to judge whether the engine is restarted after the vehicle is powered on;

[0120] a prompting module, configured to prompt the current vehicle to be in the high-speed four-wheel drive mode or the low-speed drive mode through the instrument unit after determining that the engine is restarted.

[0121] In an implementable embodiment, the four-wheel drive vehicle hill hold control device 300 further comprises:

[0122] a weather obtaining module, configured to obtain current weather information when it is determined that the vehicle is in the hill hold braking state;

[0123] a second switching module, configured to determine that the vehicle is in the easy-to-roll vehicle working condition when the current weather information is the easy-to-roll vehicle weather and the current driving mode is the high-speed two-wheel drive mode, and control the transfer case mode switch to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed driving mode.

[0124] Based on the same inventive concept, referring to Figure 3 An embodiment of the present application provides a four-wheel drive vehicle hill hold control system 300, which at least comprises:

[0125] a transfer case control unit 301, and a transfer case mode switch 305 and a parameter obtaining device connected to the transfer case control unit 301 respectively, wherein

[0126] the transfer case mode switch 305 is configured to switch the driving mode of the transfer case and transmit the current driving mode to the transfer case control unit 301, wherein the driving mode comprises a high-speed two-wheel drive mode, a high-speed four-wheel drive mode and a low-speed driving mode;

[0127] the parameter obtaining device is configured to obtain the current parameters of the vehicle and transmit the current parameters to the transfer case control unit, wherein the current parameters comprise the engine state of the vehicle, the current driving mode of the transfer case, the transmission gear, the slope of the parking position and the rolling speed;

[0128] the transfer case control unit is configured to receive the current parameters of the vehicle and execute the four-wheel drive vehicle hill hold control method of the first aspect of the present application, so as to control the transfer case mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed driving mode when it is determined that the vehicle is in the easy-to-roll vehicle working condition.

[0129] In an implementable embodiment, the parameter obtaining device comprises a vehicle body electronic stability system 302, a transmission control unit 303 and an engine control unit 304 connected to the transfer case control unit 301 respectively, wherein

[0130] the vehicle body electronic stability system 302 is configured to obtain the slope information of the parking position of the vehicle and the rolling speed and transmit the slope information and the rolling speed to the transfer case control unit 301;

[0131] the transmission control unit 303 is configured to obtain the transmission gear of the vehicle and transmit the transmission gear to the transfer case control unit 301;

[0132] The engine control unit 304 is configured to acquire the engine state of the vehicle and transmit the engine state to the transfer control unit 301;

[0133] The transfer control unit 301 is configured to receive the current driving mode, the slope information, the transmission gear and the engine state; and further configured to, in the case that the engine is in the engine-off state, transmit an instruction of switching the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to the transfer mode switch 305 when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold value; and further configured to, in the case that the engine is in the engine-on state, acquire the coasting speed of the vehicle, transmit an instruction of switching the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to the transfer mode switch 305 when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the coasting speed is greater than the speed threshold value.

[0134] In an available embodiment, the four-wheel drive vehicle hill hold control system 300 further comprises:

[0135] An instrument unit 306 and a weather acquisition unit 307 connected to the transfer control unit 301, wherein,

[0136] The weather acquisition unit 307 is configured to acquire the weather information and transmit the weather information to the transfer control unit 301;

[0137] The transfer control unit 301 is configured to receive the weather information, and transmit an instruction of switching the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode to the transfer mode switch 305 when the current driving mode is in the high-speed two-wheel drive mode and the current weather information is the easy-coasting weather; and further configured to, after switching the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode when the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, and the slope is greater than the slope threshold value, transmit a prompt instruction to the instrument unit 306 when the engine is restarted; and further configured to, after the current driving mode is in the high-speed two-wheel drive mode, the transmission gear is in the N / P gear, the slope is greater than the slope threshold value, and the coasting speed is greater than the speed threshold value, transmit a coasting warning instruction to the instrument unit 306 before determining whether a brake pedal triggered signal is received;

[0138] The instrument unit 306 is configured to receive the prompt instruction and prompt a prompt operation according to the prompt instruction to prompt that the current vehicle is in the high-speed four-wheel drive mode; and further configured to receive the coasting warning instruction and perform a warning operation according to the coasting warning instruction to remind the driver to perform a brake operation.

[0139] Based on the same inventive concept, refer to Figure 4In an embodiment of the present application, a vehicle is provided, which comprises a four-wheel drive vehicle hill holding control system 300 according to the third aspect of the present application. The four-wheel drive vehicle hill holding control system 300 can automatically switch the driving mode from a high-speed two-wheel drive mode with weak braking force to a high-speed four-wheel drive mode or a low-speed driving mode with strong braking force, without changing the braking system, by detecting the current parameters of the vehicle in real time when the vehicle is holding on a slope, and switching the driving mode automatically when the current parameters are in a state in which the vehicle is prone to rolling down the slope, so as to increase the friction between the tires and the ground and effectively reduce the risk of rolling down the slope.

[0140] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, device, or computer program product. Therefore, the embodiments of the present application can be in the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present application can be in the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0141] The embodiments of the present application are described with reference to flowcharts and / or block diagrams of the method, terminal device (system), and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, so that the instructions executed by the computer or other programmable data processing terminal device produce the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0142] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing terminal device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including instruction means that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0143] These computer program instructions can also be loaded into a computer or other programmable data processing terminal device, so that a series of operation steps are performed on the computer or other programmable terminal device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable terminal device provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 steps of the functions specified in the one or more blocks or one or more blocks.

[0144] While the preferred embodiments of the application have been described above, it should be understood that many modifications and variations to these embodiments can be derived in light of the above disclosure without departing from the scope of the present application. It is therefore intended that the appended claims shall cover all such modifications and variations as falling within the scope of the present application.

[0145] Finally, it should be noted that the terms "first", "second", and the like, herein do not denote any order, quantity, combination, or importance, but rather are used to distinguish one element from another, and are not intended to denote a physical or logical relationship between such elements. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0146] The above describes in detail the four-wheel drive vehicle hill-holding control method, device, system and vehicle provided by the present application. The principles and implementation manners of the present application are described by using specific examples. The above description of the embodiments is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application scope can be changed. In summary, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A method of hill hold control for a four-wheel drive vehicle, the method comprising: The method comprises: When it is determined that the vehicle is in the state of parking brake, current parameters of the vehicle are acquired, including engine state of the vehicle, current drive mode of the transfer case, gear position of the transmission, slope of the parking position and hill start speed; According to the current parameters, it is judged whether the vehicle is in the hill start condition, in the case that the engine is in the off state, when the current drive mode is in the high-speed two-wheel drive mode, the gear position is in the N / P gear, and the slope is greater than the slope threshold value, it is determined that the vehicle is in the hill start condition, and the high-speed two-wheel drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode; In the case that the engine is in the un-off state, when the current drive mode is in the high-speed two-wheel drive mode, the gear position is in the N / P gear, the slope is greater than the slope threshold value, and the hill start speed is greater than the speed threshold value, it is determined that the vehicle is in the hill start condition, and the high-speed two-wheel drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode; When it is determined that the vehicle is in the hill start condition, the current drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode.

2. The method of claim 1, wherein, After it is determined that the vehicle is in the hill start condition when the current drive mode is in the high-speed two-wheel drive mode, the gear position is in the N / P gear, and the slope is greater than the slope threshold value, the high-speed two-wheel drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode, the method further comprises: After the vehicle is powered on, it is judged whether the engine is restarted; After it is determined that the engine is restarted, it is prompted by the instrument unit that the current vehicle is in the high-speed four-wheel drive mode or the low-speed drive mode.

3. The method of claim 1, wherein, When it is determined that the vehicle is in the hill start condition when the current drive mode is in the high-speed two-wheel drive mode, the gear position is in the N / P gear, the slope is greater than the slope threshold value, and the hill start speed is greater than the speed threshold value, the high-speed two-wheel drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode, comprising: When it is determined that the vehicle is in the hill start condition when the current drive mode is in the high-speed two-wheel drive mode, the gear position is in the N / P gear, the slope is greater than the slope threshold value, and the hill start speed is greater than the speed threshold value, it is judged whether the brake pedal trigger signal is received within a preset time; When the brake pedal trigger signal is not received within the preset time, the high-speed two-wheel drive mode of the transfer case mode switch is switched to the high-speed four-wheel drive mode or the low-speed drive mode, and it is prompted by the instrument unit that the current vehicle is in the high-speed four-wheel drive mode or the low-speed drive mode.

4. The method of claim 1, further comprising: When it is determined that the vehicle is in the state of parking brake, current weather information is acquired; When the current weather information is easy-to-roll-off weather and the current driving mode is the high-speed two-wheel drive mode, it is determined that the vehicle is in the easy-to-roll-off condition, and the transfer mode switch is controlled to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode.

5. A four-wheel drive vehicle hill hold control device characterized by comprising: The device comprises: The acquisition module is configured to acquire current parameters of the vehicle when it is determined that the vehicle is in the state of the parking brake, including an engine state of the vehicle, a current driving mode of the transfer, a gear position of the transmission, a slope of the parking position, and a rolling-off speed on the slope; The judgment module is configured to determine whether the vehicle is in the easy-to-roll-off condition according to the current parameters, and when the engine is in the off state, it is determined that the vehicle is in the easy-to-roll-off condition when the current driving mode is the high-speed two-wheel drive mode, the gear position is the N / P gear, and the slope is greater than a slope threshold value, and the transfer mode switch is controlled to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode; When the engine is in the on state, it is determined that the vehicle is in the easy-to-roll-off condition when the current driving mode is the high-speed two-wheel drive mode, the gear position is the N / P gear, the slope is greater than the slope threshold value, and the rolling-off speed is greater than a speed threshold value, and the transfer mode switch is controlled to switch the high-speed two-wheel drive mode to the high-speed four-wheel drive mode or the low-speed drive mode; The switching module is configured to control the transfer mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed drive mode when it is determined that the vehicle is in the easy-to-roll-off condition.

6. A four-wheel drive vehicle hill hold control system characterized by, The system comprises: The transfer control unit, and a transfer mode switch and a parameter acquisition device connected to the transfer control unit, wherein The transfer mode switch is configured to switch the driving mode of the transfer, and to transmit the current driving mode to the transfer control unit, wherein the driving mode includes the high-speed two-wheel drive mode, the high-speed four-wheel drive mode, and the low-speed drive mode; The parameter acquisition device is configured to acquire the current parameters of the vehicle, and to transmit the current parameters to the transfer control unit; The transfer control unit is configured to receive the current parameters of the vehicle, and to perform the method of any one of claims 1-4 to control the transfer mode switch to switch the current driving mode to the high-speed four-wheel drive mode or the low-speed drive mode when it is determined that the vehicle is in the easy-to-roll-off condition.

7. The system of claim 6, wherein, The parameter acquisition device comprises: A vehicle body electronic stability system, a transmission control unit, and an engine control unit connected to the transfer control unit, wherein The vehicle body electronic stability system is configured to acquire slope information and a rolling-off speed of the parking position of the vehicle, and to transmit the slope information and the rolling-off speed to the transfer control unit; The transmission control unit is configured to acquire the gear position of the vehicle, and to transmit the gear position to the transfer control unit; The engine control unit is configured to acquire the engine state of the vehicle, and to transmit the engine state to the transfer control unit.

8. A vehicle characterized by comprising: A four-wheel drive vehicle hill hold control system including any one of claims 6 and 7.

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