CN116767205A

CN116767205A - Vehicle speed control method and system based on off-road cruising function

Info

Publication number: CN116767205A
Application number: CN202310931422.XA
Authority: CN
Inventors: 张温; 李超; 庞志强; 黄如兵; 张汝琳
Original assignee: China National Heavy Duty Truck Group Jinan Power Co Ltd
Current assignee: China National Heavy Duty Truck Group Jinan Power Co Ltd
Priority date: 2023-07-27
Filing date: 2023-07-27
Publication date: 2023-09-19

Abstract

The application provides a vehicle speed control method and a vehicle speed control system based on an off-road cruising function, wherein the method is operated in a vehicle body electronic stability control system and comprises the following steps: receiving a switch request signal for starting an off-road cruising function, judging whether one of the conditions that TOD is in a 4L mode, a gear D of a gearbox or an electronic parking brake system is released is met, and if so, activating the off-road cruising function; after receiving a brake pedal release command, sending an engine torque lifting control command to an engine management system to enable the engine management system to execute engine torque lifting control; and simultaneously calculating the current vehicle speed, comparing the current vehicle speed with the cruising target vehicle speed, and continuously controlling the engine management system to adjust the engine torque so that the current vehicle speed is equal to the cruising target vehicle speed. Based on the method, a vehicle speed control system based on an off-road cruising function is also provided. The application enables the vehicle to achieve the performance targets of simple, comfortable and safe driving.

Description

Vehicle speed control method and system based on off-road cruising function

Technical Field

The application belongs to the technical field of vehicle speed control, and particularly relates to a vehicle speed control method and system based on an off-road cruising function.

Background

Off-road vehicles are vehicles that are specifically designed for off-road use. The main characteristics are four-wheel drive, higher chassis, better grip tires, higher exhaust pipes, higher horsepower and thick and firm bumpers.

The traditional off-road vehicle is matched with a four-wheel drive system, when the vehicle runs on a road condition with complex, bumpy and tortuous routes or a steep and dangerous mountain area, a driver needs to put in great effort to control the accelerator and the brake to control the vehicle speed, and in the process of intense driving, the planning and maintenance of the driving route are difficult to become more than usual, so that the off-road driving is often highly dependent on the driving skill of the driver, and the playability of the on-road player and the safety of the driving process are limited. The traditional cruising function can be activated only after the vehicle reaches a higher speed, which obviously cannot be suitable for the off-road low-speed driving condition.

Disclosure of Invention

In order to solve the technical problems, the application provides a vehicle speed control method and a vehicle speed control system based on an off-road cruising function, so that a vehicle achieves the performance targets of simplicity, comfort and safety in driving.

In order to achieve the above purpose, the present application adopts the following technical scheme:

a vehicle speed control method based on an off-road cruising function operates in an electronic stability control system of a vehicle body, and comprises the following steps:

receiving a switch request signal for starting an off-road cruising function, judging whether one of the conditions that TOD is in a 4L mode, a gear D of a gearbox or an electronic parking brake system is released is met, and if so, activating the off-road cruising function;

after receiving a brake pedal release command, sending an engine torque lifting control command to an engine management system to enable the engine management system to execute engine torque lifting control; and simultaneously calculating the current vehicle speed, comparing the current vehicle speed with the cruising target vehicle speed, and continuously controlling the engine management system to adjust the engine torque so that the current vehicle speed is equal to the cruising target vehicle speed.

Further, the method for calculating the current vehicle speed comprises the following steps: the electronic stability control system of the vehicle body calculates the current vehicle speed according to the acquired front left wheel speed, front right wheel speed, rear left wheel speed and rear right wheel speed.

Further, the method further comprises: in the off-road cruise function on state, the first cruise target vehicle speed is increased or decreased.

Further, the method further comprises: under the state that the off-road cruising function is started, receiving an accelerator pedal signal, and if the accelerator pedal is stepped on, deactivating the cruising function, so that the vehicle speed is increased along with the intention of a driver; if the accelerator pedal is released, the magnitude of the cruise target vehicle speed is determined again.

Further, the method further comprises: receiving a brake pedal signal when the off-road cruising function is started, and if the brake pedal is stepped on, deactivating the cruising function, wherein the vehicle speed is reduced along with the intention of a driver; if the brake pedal is released, the magnitude of the cruise target vehicle speed is determined again.

Further, the method further comprises: under the starting state of the off-road cruising function, the electronic stability control system of the vehicle body judges whether the cruising target vehicle speed is required to be realized by the engine torque up or torque down according to the gear of the gearbox, the actual torque of the flywheel end of the engine, the rotating speed of the transmitter and the wheel speed, and if the torque up or torque down is required, the electronic stability control system of the vehicle body controls the engine management system to execute the torque up or torque down operation; if the cruise target vehicle speed can not be achieved only through engine torque control, the vehicle body electronic stability control system judges whether braking intervention is needed to achieve the cruise target vehicle speed, and if so, a brake lamp is turned on and a brake pipeline is simultaneously pressed.

Further, the method further comprises: in the off-road cruising function on state, if the vehicle body electronic stability control system calculates that the current vehicle speed is not equal to the cruising target vehicle speed, the engine management system is controlled to make the vehicle stable at the cruising target vehicle speed.

Further, the method further comprises: and in the off-road cruising function starting state, the electronic stability control system of the vehicle body receives the TAB turning auxiliary braking function signal and forwards the TAB turning auxiliary braking function signal to the PBC controller, and when the PBC controller detects that the corner signal value is greater than 90% of the maximum corner, the TAB turning auxiliary braking function is started, and the cruising target vehicle speed is set through the cruising switch, the accelerator and the brake pedal.

Further, the method further comprises: in the off-road cruise function on state, a switch request signal to turn off the off-road cruise function is received and the off-road cruise function is executed.

The application also provides a vehicle speed control system based on the off-road cruising function, which comprises an activating module and a control module;

the activation module is used for receiving a switch request signal for starting the off-road cruising function, judging whether one of the conditions of TOD in a 4L mode, D gear of a gearbox or release of an electronic parking brake system is met, and activating the off-road cruising function if the condition is met;

the control module is used for sending an engine torque lifting control instruction to the engine management system after receiving a brake pedal loosening command so that the engine management system can execute engine torque lifting control; and simultaneously calculating the current vehicle speed, comparing the current vehicle speed with the cruising target vehicle speed, and continuously controlling the engine management system to adjust the engine torque so that the current vehicle speed is equal to the cruising target vehicle speed.

The effects provided in the summary of the application are merely effects of embodiments, not all effects of the application, and one of the above technical solutions has the following advantages or beneficial effects:

the application provides a vehicle speed control method and a vehicle speed control system based on an off-road cruising function, wherein the method is operated in a vehicle body electronic stability control system and comprises the following steps: receiving a switch request signal for starting an off-road cruising function, judging whether one of the conditions that TOD is in a 4L mode, a gear D of a gearbox or an electronic parking brake system is released is met, and if so, activating the off-road cruising function; after receiving a brake pedal release command, sending an engine torque lifting control command to an engine management system to enable the engine management system to execute engine torque lifting control; and simultaneously calculating the current vehicle speed, comparing the current vehicle speed with the cruising target vehicle speed, and continuously controlling the engine management system to adjust the engine torque so that the current vehicle speed is equal to the cruising target vehicle speed. A vehicle speed control system based on the off-road cruising function is also provided. The application enables the vehicle to achieve the performance targets of simple, comfortable and safe driving.

According to the application, a driver can start the CCO off-road cruising function in real time according to road conditions, under the complex road conditions such as mountain areas, curves and the like, the driver does not need to control an accelerator pedal and a brake pedal all the time under the function activation, and the CCO system realizes stable control of the vehicle speed of 5 km/h-15 km/h according to the target vehicle speed requested by the driver, so that the cruising vehicle speed range is wider.

According to the application, the cruise speed control is realized by optimizing the gear shifting strategy of the gearbox, and meanwhile, the engine is ensured to work in a reasonable and efficient rotating speed range, so that the speed stability is high. Meanwhile, the problem of speed fluctuation of the conventional gear shifting strategy cruise working condition is avoided, the problem of narrow cruise speed range and overhigh engine speed caused by single gear control is avoided, and the cruise function is comfortable and good in economical efficiency.

According to the application, through optimizing the engine torque request strategy, the problems of vehicle movement and vehicle shake caused by continuous clamping and releasing of the brake calipers after the TAB function is activated are solved, and the stable control of the vehicle speed of the TAB function is realized. And the vehicle speed in the switching process of different road surfaces is well transited, and the control is stable.

Drawings

Fig. 1 is a signal flow chart of a vehicle speed control method based on an off-road cruising function according to embodiment 1 of the present application;

FIG. 2 is a flow chart of the off-road cruise function execution proposed by embodiment 1 of the present application;

FIG. 3 is a flowchart showing the TAB function execution proposed in embodiment 1 of the present application;

fig. 4 is a schematic diagram of a vehicle speed control system based on an off-road cruise function according to embodiment 2 of the present application.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present application will be described in detail below with reference to the following detailed description and the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different structures of the application. In order to simplify the present disclosure, components and arrangements of specific examples are described below. Furthermore, the present application may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and processes are omitted so as to not unnecessarily obscure the present application.

Example 1

The embodiment 1 of the application provides a vehicle speed control method based on an off-road cruising function, so that a vehicle achieves the performance targets of simplicity, comfort and safety in driving.

CCO is a value-added function that helps stabilize vehicle speed at a target vehicle speed through active control. The vehicle controls speed without driver intervention. Starting the vehicle, switching the gear box to N gear, and switching the TOD to 4L; and D, stepping on the brake, loosening the EPB, and pressing a CCO button to realize the opening and closing of the CCO function. After CCO is activated, a brake pedal is released, the vehicle automatically starts to accelerate to the current target vehicle speed, and the vehicle speed is stabilized to run. If desired, the driver may change the target speed by means of a brake pedal or an accelerator pedal, a cruise switch. The speed control precision of the brake pedal and the accelerator pedal is low, and especially, a novice driver is difficult to quickly adjust the target speed in place; the cruise switch control is added, so that the target vehicle speed can be adjusted in a grading manner according to the set control precision, and the control is accurate and simple.

The TOD controller is a four-wheel drive control system.

In the cruising process, a driver does not need to control an accelerator and brake, and can concentrate on controlling the direction, so that the vehicle can more accurately run along an expected route, and the driving safety is improved.

Fig. 1 is a signal flow chart of a vehicle speed control method based on an off-road cruising function according to embodiment 1 of the present application; the modules required for implementing the method include: an ESP controller, a TCU controller communicatively connected to the ESP controller, an EMS engine controller, a TOD controller, an instrument, a BLS brake light switch, a CCO switch, a brake light, a steering wheel angle, a TAB switch, and a PBC controller.

The definition of the signals in the present application is given in table 1 below:

wherein the TCU controller is connected to the shift button.

when the ESP controller receives the CCO Switch request signal GW_CCO_switch, the electronic stability control system of the vehicle body firstly judges whether the value of the signal GW_CCO_switch is 0x1, if the value is 0x1, the driver requests to enter a CCO function, and the ESP controller judges the current TOD mode, the gear of the gearbox and the EPB state: if the mode is TOD or the transmission is not D or EPB is not released, the CCO function is not activated; if TOD is in 4L mode, or transmission D-range, or EPB is released, the CCO function is ready to switch to on-state.

Wherein gw_cco_switch indicates CCO Switch status; 0x0, not pressed; 0x1, pressing down; 0x2:reserved;0x3, invalid.

EPB is an electronic parking brake system.

The CCO function is ready to switch to on state, the driver releases the brake pedal, the ESP controller sends esp_cco_ TargetEngineTorque, ESP _targetenginetorquerrelease to the EMS, which is the engine management system, which receives and then controls the engine torque up and down according to the request signal value, calculates the current vehicle speed according to the esp_wheelspeed_fl, esp_wheelspeed_fr, esp_wheelspeed_rl, esp_wheelspeed_rr signals, and compares the current target vehicle speed with the cruise target vehicle speed esp_drivetargetvelocity, and continuously adjusts the esp_cco_ TargetEngineTorque, ESP _targetenginetorquerrelease to the EMS until the vehicle reaches the current target vehicle speed. The default target vehicle speed after CCO activation is 5km/h.

Wherein ESP_CCO_TargetEngineToque is the target engine torque up control command and ESP_TargetEngineTorToque release is the target engine torque down control command.

The process realized by the application also comprises the following steps: in the off-road cruise function on state, the first cruise target vehicle speed is increased or decreased.

In the CCO function activated state, the cruise switch is utilized to increase/decrease the cruise target speed, the ESP controller calculates the current speed according to ESP_Wheelspeed_FL, ESP_Wheelspeed_FR, ESP_Wheelspeed_RL and ESP_Wheelspeed_RR signals, and the current speed is compared with the current target speed, and the ESP_CCO_ TargetEngineTorque, ESP _TargetEngineTorTorque release is continuously adjusted and sent to the EMS until the vehicle reaches the current target speed.

And (3) reducing the working condition of the target vehicle speed, if the target vehicle speed cannot be realized by the independent engine torque control, sending an ESP_BLRequestController signal value 0x0 to a gateway by the ESP controller, sending the signal value to EMS, TCU, IP by the gateway, and turning on a brake lamp and simultaneously building a brake pipeline to build pressure so as to perform CCO target vehicle speed control. The setting range of the target vehicle speed is generally 5 km/h-10 km/h, and the control strategy can realize the control of the vehicle speed of 5 km/h-15 km/h.

ESP_BLRequestController represents that the brake light is on, 0x0 is braking force; 0x1, no braking force.

The process realized by the application also comprises the following steps: under the state that the off-road cruising function is started, receiving an accelerator pedal signal, and if the accelerator pedal is stepped on, deactivating the cruising function, so that the vehicle speed is increased along with the intention of a driver; if the accelerator pedal is released, the magnitude of the cruise target vehicle speed is determined again.

In the CCO function activation state, the driver steps on the accelerator, the CCO function is not activated, and the vehicle speed is increased along with the intention of the driver. After throttle release, the ESP controller calculates the current vehicle speed from the ESP_WheelSpeed_FL, ESP_WheelSpeed_FR, ESP_WheelSpeed_RL, and ESP_WheelSpeed_RR signals. And if the current vehicle speed is not more than 15km/h, activating the CCO system, and performing cruise control by taking the current vehicle speed as a new target vehicle speed. If the current speed is greater than 15km/h and not greater than 30km/h, the CCO system is activated, the cruising target speed is set to 15km/h, the CCO system sends an ESP_BLRequestController signal value 0x0 to the gateway, the gateway sends the signal value to EMS, TCU, IP, a brake lamp is lightened, a brake pipeline is built up, and cruising control is performed after the speed is 15 km/h. If the current speed is greater than 30km/h, the CCO system exits. Wherein IP is the instrumentation system.

The process realized by the application also comprises the following steps: receiving a brake pedal signal when the off-road cruising function is started, and if the brake pedal is stepped on, deactivating the cruising function, wherein the vehicle speed is reduced along with the intention of a driver; if the brake pedal is released, the magnitude of the cruise target vehicle speed is determined again.

In the CCO function activated state, the driver depresses the brake pedal, the CCO function is deactivated, and the vehicle speed decreases with the intention of the driver. The driver releases the brake pedal and the ESP controller calculates the current vehicle speed according to the ESP_Wheelspeed_FL, the ESP_Wheelspeed_FR, the ESP_Wheelspeed_RL and the ESP_Wheelspeed_RR signals, and if the current vehicle speed is not more than 15km/h, the CCO system is activated, and the current vehicle speed is used as a new target vehicle speed ESP_drive target vehicle speed for cruise control. If the current speed is greater than 15km/h and not greater than 30km/h, the CCO system is activated, the cruising target speed is set to 15km/h, the CCO system sends an ESP_BLRequestController signal value 0x0 to the gateway, the gateway sends the signal value to EMS, TCU, IP, a brake lamp is lightened, a brake pipeline is built up, and cruising control is performed after the speed is 15 km/h. If the current speed is greater than 30km/h, the CCO system exits.

Wherein ESP_DriveTargetVecity is the drive target speed.

The process realized by the application also comprises the following steps: under the starting state of the off-road cruising function, the electronic stability control system of the vehicle body judges whether the cruising target vehicle speed is required to be realized by the engine torque up or torque down according to the gear of the gearbox, the actual torque of the flywheel end of the engine, the rotating speed of the transmitter and the wheel speed, and if the torque up or torque down is required, the electronic stability control system of the vehicle body controls the engine management system to execute the torque up or torque down operation; if the cruise target vehicle speed can not be achieved only through engine torque control, the vehicle body electronic stability control system judges whether braking intervention is needed to achieve the cruise target vehicle speed, and if so, a brake lamp is turned on and a brake pipeline is simultaneously pressed.

In the CCO function active state, the ESP controller receives TCU_ CurrentGear, EMS _ EffectiveEngineTorque, EMS _ EngineSpeed, ESP _WheelSpeed_FL, ESP_WheelSpeed_FR, ESP_WheelSpeed_RL, ESP_WheelSpeed_RR to determine whether an engine torque up is required or will be required to achieve the CCO target vehicle speed ESP_DriveTargetVecity, if a torque reduction of the engine is required, the ESP controller sends an ESP_Basc signal value 0x1, an ESP_CCO_TargetEngineTorTorque, or a certain value between the ESP_TargetEngineTorTorTorRelease signal values 0x 1-0 Xffe to the EMS, and the EMS executes a torque reduction request; if the engine is required to be up-twisted, the ESP controller sends an ESP_Torque IncSt signal value 0x1, a certain value between the ESP_CCO_TargetEngineTorTorque signal values 0x 1-0 Xffe to the EMS, and the EMS executes an up-twisted request; thereby realizing CCO target vehicle speed esp_drivertargetviocity.

If the engine torque is not needed, or the target vehicle speed cannot be realized simply through engine torque control, the ESP controller judges whether braking intervention is needed to realize the CCO target vehicle speed, if the braking intervention is needed, the ESP controller sends an ESP_BLRequestController signal value 0x0 to a gateway, the gateway sends the signal value to EMS, TCU, IP, a brake lamp is turned on, and meanwhile, a brake pipeline is pressurized, so that the CCO target vehicle speed is controlled.

Wherein TCU_Currentgear is the current gear of TCU; 0x0, the drive chain is disconnected; 0x1:gear 1;0x2:gear 2;0x3:gear 3;0x4:gear 4;0x5:gear 5;0x6:gear 6;0x7:gear 7;0x8:gear 8;0x 9-0 xD; 0xE: gear R;0xF, invalid.

EMS_effective EngineTorTorTorTorTorTherTherTherEquipped is the actual torque of the flywheel end of the engine; 0x0: minimum, -300

0xA28: maximum value, 1000; offset amount: -300; precision: 0.5.

EMS_EngineSpeed is the engine speed.

The process realized by the application also comprises the following steps: in the off-road cruising function on state, if the vehicle body electronic stability control system calculates that the current vehicle speed is not equal to the cruising target vehicle speed, the engine management system is controlled to make the vehicle stable at the cruising target vehicle speed.

In the CCO function activation state, such as the vehicle is ascending a slope, the vehicle resistance is increasing, the ESP controller calculates that the real-time vehicle speed is smaller than the current target vehicle speed, based on the difference between the current vehicle speed and the target vehicle speed, ESP_CCO_ TargetEngineTorque, ESP _TargetEngineTorTorTorRelease is sent to the EMS to stabilize the vehicle at the current target vehicle speed. If the vehicle runs down a slope and accelerates, and the current vehicle speed is greater than the target vehicle speed, the ESP controller sends an ESP_BLRequestController signal value 0x0 to the gateway, the gateway sends the signal value to EMS, TCU, IP, and a brake lamp is turned on and a brake pipeline is simultaneously pressed for CCO target vehicle speed control. According to the application, a gear shifting strategy of the gearbox is optimized, the cruising speed in the original control strategy corresponds to the highest gear from 5 gears to 6 gears, the rotating speed of an engine is below 1200r/min, when a vehicle CCO mode goes up a slope, the running resistance is increased, and the speed is reduced; the speed of the gearbox is increased by gear-down and torque-up, and the speed of the vehicle is slowly increased again. In the existing reference control strategy, the gear of the gearbox is locked to be 1 gear, the cruising speed is up to 10km/h, the corresponding engine speed is more than 4000r/min, the engine noise is high at the moment, the engine speed is obviously beyond the rated speed 2500r/min of the diesel engine, and the method is not suitable for diesel vehicles. In order to solve the problem, the control strategy optimizes a gear shifting strategy of the gearbox, the corresponding rotating speed of a gear shifting point is increased in a 4L mode, the highest cruising speed is 15km/h, the corresponding gear of the gearbox is 3 gears, and the rotating speed of an engine is below 1700 r/min. Through verification, the vehicle speed fluctuation caused by the running resistance change of different slopes and complex road surfaces can be avoided under the strategy, and the cruise vehicle speed is stably controlled to be 5 km/h-15 km/h.

The process realized by the application also comprises the following steps: and in the off-road cruising function starting state, the electronic stability control system of the vehicle body receives the TAB turning auxiliary braking function signal and forwards the TAB turning auxiliary braking function signal to the PBC controller, and when the PBC controller detects that the corner signal value is greater than 90% of the maximum corner, the TAB turning auxiliary braking function is started, and the cruising target vehicle speed is set through the cruising switch, the accelerator and the brake pedal.

Fig. 3 is a flowchart of TAB function execution proposed in embodiment 1 of the present application.

In the CCO function activation state, a TAB turning auxiliary brake function Switch is pressed, an ESP controller receives a GW_TAB_switch signal, a signal value 0x1 is forwarded to the PBC controller, the TAB system enters a standby state, and the PBC controller sends an ESP_TABSts signal value 0x1 to the ESP controller. The PBC controller detects a steering wheel angle signal SAS_SteerWheeleAngle, when the angle signal value is larger than 90% of the maximum angle, the TAB function is switched into an active state, and the PBC controller sends an ESP_TABSts signal value 0x2; when the driver releases the brake pedal, the vehicle starts.

Taking a left turn as an example, in the TAB function activation process, the PBC controller sends PBC_caliper_L_APPLY and PBC_caliper_L_release to the ESP controller according to a specified logic, and the ESP controller realizes clamping and releasing of the inner rear wheel calipers according to a set slip rate.

The control strategy optimizes TAB slip ratio setting parameters and reduces turning radius. Meanwhile, an engine control strategy of a CCO function is optimized, the engine torque request slope is reduced based on the response characteristic of the diesel engine, the engine response is ensured to be close to a CCO request value, and the vehicle speed fluctuation and starting movement caused by overshoot control and response delay are avoided. The control strategy realizes the stable control of the speed in the TAB activation state turning process, realizes the stable transition of the speed of switching different road surfaces, and improves the functional comfort and the driving safety. In the TAB activation state of the control strategy, the CCO speed can still be set through a cruise switch, an accelerator and a brake pedal. Reference is made in particular to the above method procedure.

In CCO and TAB function activation states, when the rotation angle signal value is smaller than 90% of the maximum rotation angle, the TAB function is switched into standby state, and the PBC controller sends an ESP_TABSts signal value of 0x1; the TAB turning auxiliary brake function Switch is pressed again, the ESP controller receives the gw_tab_switch signal with a signal value of 0x0, the ESP controller forwards to the PBC controller, the TAB system enters a function OFF state, and the PBC controller sends an esp_tabs signal value of 0x0 to the ESP controller. The ESP controller forwarding controller sends the esp_tabs signal value 0x0 to the gateway and the gateway forwarding controller sends the esp_tabs signal value 0x0 to the meter, which no longer displays TAB ON and TAB function exits.

The process realized by the application also comprises the following steps: in the off-road cruise function on state, a switch request signal to turn off the off-road cruise function is received and the off-road cruise function is executed.

When the CCO is in an active state, the driver presses the CCO switch again, the ESP controller receives the CCO switch request signal gw_ccoswitch to switch to 0x0, indicating that the driver requests to exit CCO control, the ESP controller sends an esp_ccostatus signal value of 0x0 to the gateway, the gateway sends the signal value to EMS, TCU, TOD, IP, the instrument CCO ON information is no longer displayed, the CCO switch indicator is turned off, and the CCO function exits. When the CCO is in an activated state, the driver exits the 4L mode, and the TOD controller sends TOD_SystemOperMode to the ESP controller; the ESP controller judges that the CCO activation condition is not met, and sends an ESP_CCOStatus signal value 0x0 to the gateway; the gateway sends the signal value to EMS, TCU, TOD, IP and the meter CCO ON message is no longer displayed and the CCO switch indicator is turned off and the CCO function exits. When CCO is in an activated state, the driver exits from the D gear, and the TCU sends TCU_CurrentGear to the ESP controller; the ESP controller judges that the CCO activation condition is not met, and sends an ESP_CCOStatus signal value 0x0 to the gateway; the gateway sends the signal value to EMS, TCU, TOD, IP and the meter CCO ON message is no longer displayed and the CCO switch indicator is turned off and the CCO function exits.

The vehicle speed control method based on the off-road cruising function provided by the embodiment 1 of the application enables the vehicle to achieve the performance targets of simplicity, comfort and safety in driving.

According to the vehicle speed control method based on the off-road cruising function, provided by the embodiment 1 of the application, a driver can start the CCO off-road cruising function in real time according to road conditions, under the condition of function activation in mountain areas, curves and other complex road conditions, the driver does not need to control an accelerator pedal and a brake pedal all the time, the CCO system realizes stable control of the vehicle speed of 5km/h to 15km/h according to the target vehicle speed requested by the driver, and the cruising vehicle speed range is wider.

In the vehicle speed control method based on the off-road cruising function, which is provided by the embodiment 1 of the application, the cruising vehicle speed control is realized by optimizing the gear shifting strategy of the gearbox, and meanwhile, the engine is ensured to work in a reasonable and efficient rotating speed range, and the vehicle speed stability is high. Meanwhile, the problem of speed fluctuation of the conventional gear shifting strategy cruise working condition is avoided, the problem of narrow cruise speed range and overhigh engine speed caused by single gear control is avoided, and the cruise function is comfortable and good in economical efficiency.

In the vehicle speed control method based on the off-road cruising function, provided by the embodiment 1 of the application, the problems of vehicle movement and vehicle shake caused by continuous clamping and releasing of the brake calipers after the TAB function is activated are solved by optimizing the engine torque request strategy, and the vehicle speed stability control of the TAB function is realized. And the vehicle speed in the switching process of different road surfaces is well transited, and the control is stable.

Example 2

Based on the vehicle speed control method based on the off-road cruising function provided in embodiment 1 of the present application, embodiment 2 of the present application further provides a vehicle speed control system based on the off-road cruising function, and fig. 4 is a schematic diagram of the vehicle speed control system based on the off-road cruising function provided in embodiment 2 of the present application, where the system includes: an activation module and a control module;

the activation module is used for receiving a switch request signal for starting the off-road cruising function, judging whether one of the conditions that TOD is in a 4L mode, the D gear of the gearbox or the electronic parking brake system is released is met, and if so, activating the off-road cruising function;

The control module comprises: the method for calculating the current vehicle speed comprises the following steps: the electronic stability control system of the vehicle body calculates the current vehicle speed according to the acquired front left wheel speed, front right wheel speed, rear left wheel speed and rear right wheel speed.

The control module further comprises:

in the off-road cruise function on state, the first cruise target vehicle speed is increased or decreased.

Under the state that the off-road cruising function is started, receiving an accelerator pedal signal, and if the accelerator pedal is stepped on, deactivating the cruising function, so that the vehicle speed is increased along with the intention of a driver; if the accelerator pedal is released, the magnitude of the cruise target vehicle speed is determined again.

Receiving a brake pedal signal when the off-road cruising function is started, and if the brake pedal is stepped on, deactivating the cruising function, wherein the vehicle speed is reduced along with the intention of a driver; if the brake pedal is released, the magnitude of the cruise target vehicle speed is determined again.

Under the starting state of the off-road cruising function, the electronic stability control system of the vehicle body judges whether the cruising target vehicle speed is required to be realized by the engine torque up or torque down according to the gear of the gearbox, the actual torque of the flywheel end of the engine, the rotating speed of the transmitter and the wheel speed, and if the torque up or torque down is required, the electronic stability control system of the vehicle body controls the engine management system to execute the torque up or torque down operation; if the cruise target vehicle speed can not be achieved only through engine torque control, the vehicle body electronic stability control system judges whether braking intervention is needed to achieve the cruise target vehicle speed, and if so, a brake lamp is turned on and a brake pipeline is simultaneously pressed.

In the off-road cruising function on state, if the vehicle body electronic stability control system calculates that the current vehicle speed is not equal to the cruising target vehicle speed, the engine management system is controlled to make the vehicle stable at the cruising target vehicle speed.

And in the off-road cruising function starting state, the electronic stability control system of the vehicle body receives the TAB turning auxiliary braking function signal and forwards the TAB turning auxiliary braking function signal to the PBC controller, and when the PBC controller detects that the corner signal value is greater than 90% of the maximum corner, the TAB turning auxiliary braking function is started, and the cruising target vehicle speed is set through the cruising switch, the accelerator and the brake pedal.

In the off-road cruise function on state, a switch request signal to turn off the off-road cruise function is received and the off-road cruise function is executed.

The vehicle speed control system based on the off-road cruising function provided by the embodiment 2 of the application enables the vehicle to achieve the performance targets of simplicity, comfort and safety in driving.

In the vehicle speed control system based on the off-road cruising function provided by the embodiment 2 of the application, a driver can start the CCO off-road cruising function in real time according to road conditions, under the condition of complex road conditions such as mountainous regions, curves and the like, the driver does not need to control an accelerator pedal and a brake pedal all the time, the CCO system realizes stable control of the vehicle speed of 5km/h to 15km/h according to the target vehicle speed requested by the driver, and the cruising vehicle speed range is wider.

In the vehicle speed control system based on the off-road cruising function, which is provided by the embodiment 2 of the application, the cruising vehicle speed control is realized by optimizing the gear shifting strategy of the gearbox, and meanwhile, the engine is ensured to work in a reasonable and efficient rotating speed range, and the vehicle speed stability is high. Meanwhile, the problem of speed fluctuation of the conventional gear shifting strategy cruise working condition is avoided, the problem of narrow cruise speed range and overhigh engine speed caused by single gear control is avoided, and the cruise function is comfortable and good in economical efficiency.

In the vehicle speed control system based on the off-road cruising function provided by the embodiment 2 of the application, the problems of vehicle movement and vehicle shake caused by continuous clamping and releasing of the brake calipers after the TAB function is activated are solved by optimizing the engine torque request strategy, and the vehicle speed stability control of the TAB function is realized. And the vehicle speed in the switching process of different road surfaces is well transited, and the control is stable.

The description of the relevant parts in the vehicle speed control system based on the off-road cruising function provided by the embodiment of the application can be referred to the detailed description of the corresponding parts in the vehicle speed control method based on the off-road cruising function provided by the embodiment 1 of the application, and will not be repeated here.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is inherent to. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element. In addition, the parts of the above technical solutions provided in the embodiments of the present application, which are consistent with the implementation principles of the corresponding technical solutions in the prior art, are not described in detail, so that redundant descriptions are avoided.

While the specific embodiments of the present application have been described above with reference to the drawings, the scope of the present application is not limited thereto. Other modifications and variations to the present application will be apparent to those of skill in the art upon review of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. On the basis of the technical scheme of the application, various modifications or variations which can be made by the person skilled in the art without the need of creative efforts are still within the protection scope of the application.

Claims

1. The vehicle speed control method based on the off-road cruising function is characterized by running in an electronic stability control system of a vehicle body and comprising the following steps of:

2. The method for controlling vehicle speed based on off-road cruise function according to claim 1, wherein the method for calculating the current vehicle speed is as follows: the electronic stability control system of the vehicle body calculates the current vehicle speed according to the acquired front left wheel speed, front right wheel speed, rear left wheel speed and rear right wheel speed.

3. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: in the off-road cruise function on state, the first cruise target vehicle speed is increased or decreased.

4. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: under the state that the off-road cruising function is started, receiving an accelerator pedal signal, and if the accelerator pedal is stepped on, deactivating the cruising function, so that the vehicle speed is increased along with the intention of a driver; if the accelerator pedal is released, the magnitude of the cruise target vehicle speed is determined again.

5. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: receiving a brake pedal signal when the off-road cruising function is started, and if the brake pedal is stepped on, deactivating the cruising function, wherein the vehicle speed is reduced along with the intention of a driver; if the brake pedal is released, the magnitude of the cruise target vehicle speed is determined again.

6. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: under the starting state of the off-road cruising function, the electronic stability control system of the vehicle body judges whether the cruising target vehicle speed is required to be realized by the engine torque up or torque down according to the gear of the gearbox, the actual torque of the flywheel end of the engine, the rotating speed of the transmitter and the wheel speed, and if the torque up or torque down is required, the electronic stability control system of the vehicle body controls the engine management system to execute the torque up or torque down operation; if the cruise target vehicle speed can not be achieved only through engine torque control, the vehicle body electronic stability control system judges whether braking intervention is needed to achieve the cruise target vehicle speed, and if so, a brake lamp is turned on and a brake pipeline is simultaneously pressed.

7. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: in the off-road cruising function on state, if the vehicle body electronic stability control system calculates that the current vehicle speed is not equal to the cruising target vehicle speed, the engine management system is controlled to make the vehicle stable at the cruising target vehicle speed.

8. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: and in the off-road cruising function starting state, the electronic stability control system of the vehicle body receives the TAB turning auxiliary braking function signal and forwards the TAB turning auxiliary braking function signal to the PBC controller, and when the PBC controller detects that the corner signal value is greater than 90% of the maximum corner, the TAB turning auxiliary braking function is started, and the cruising target vehicle speed is set through the cruising switch, the accelerator and the brake pedal.

9. The off-road cruise function-based vehicle speed control method according to claim 1, characterized in that the method further comprises: in the off-road cruise function on state, a switch request signal to turn off the off-road cruise function is received and the off-road cruise function is executed.

10. The vehicle speed control system based on the off-road cruising function is characterized by comprising an activating module and a control module;