Vehicle downhill control methods and vehicles

Abstract

This invention belongs to the field of vehicle technology and discloses a vehicle downhill control method and vehicle. The vehicle downhill control method includes a downhill cruise mode. When the activation conditions for the downhill cruise mode are met, the vehicle enters the downhill cruise mode, using the vehicle speed at the time of entry as the set speed. The method calculates the total braking force required for the vehicle to descend the slope at the set speed. It compares the maximum electric braking force provided by the motor with the total braking force. When the maximum electric braking force provided by the motor is greater than or equal to the total braking force, the motor is controlled to apply electric braking with the total braking force. When the maximum electric braking force provided by the motor is less than the total braking force, the motor is controlled to apply electric braking with the maximum electric braking force, and the air brake controller is controlled to implement air braking to compensate for the electric braking. By timely intervention of the air brake, the electric braking can be compensated, allowing the vehicle to decelerate to a safe speed that the motor can maintain for a uniform downhill descent, without driver intervention.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and more particularly to a method for controlling vehicle downhill and a vehicle. Background Technology

[0002] In terms of braking for non-drive-by-wire chassis new energy engineering vehicles, many new energy vehicles currently use a combination of slow braking and pedal braking. Slow braking is achieved by reversing the motor. This braking method can only provide electric braking at low speeds, depending on the slope and vehicle speed. Moreover, it is necessary to frequently adjust the slow braking lever to output different braking forces to decelerate or maintain the vehicle speed. When the vehicle speed is high or the vehicle load is high, the electric braking will be insufficient, and air braking can only be added by the brake pedal to ensure the vehicle's braking capacity. The driver needs to frequently press the brake pedal, which not only makes the driver more fatigued but also makes it difficult to control the vehicle speed stably. Summary of the Invention

[0003] The purpose of this invention is to provide a vehicle downhill control method and vehicle that can achieve a stable downhill speed, avoid the risk of speeding and rolling back, and eliminate the need for driver control.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] A vehicle downhill control method, including a downhill cruise mode, wherein the downhill cruise mode includes:

[0006] When the conditions for starting the downhill cruise mode are met, the vehicle enters the downhill cruise mode and uses the vehicle speed at the moment of entering the downhill cruise mode as the set speed.

[0007] Calculate the total braking force required for the vehicle to descend the slope at the set speed at a constant speed.

[0008] The maximum electric braking force that the motor can provide is compared with the total braking force. When the maximum electric braking force that the motor can provide is greater than or equal to the total braking force, the motor is controlled to perform electric braking with the total braking force. When the maximum electric braking force that the motor can provide is less than the total braking force, the motor is controlled to perform electric braking with the maximum electric braking force, and the air brake controller is controlled to implement air braking to compensate for the electric braking.

[0009] As a preferred technical solution for vehicle downhill control, the activation conditions of the downhill cruise mode include activating the downhill cruise rocker switch, deactivating the deceleration lever, releasing the accelerator pedal, releasing the brake pedal, and releasing the handbrake.

[0010] As a preferred technical solution for vehicle downhill control, calculating the total braking force required for the vehicle to descend a slope at a set speed includes:

[0011] The feedforward braking force is calculated based on the vehicle's longitudinal dynamics formula, the vehicle's empty and fully loaded states, and the gradient of the downhill slope.

[0012] The compensating braking force is calculated based on the difference between the set vehicle speed and the actual vehicle speed.

[0013] The total braking force is obtained by adding the feedforward braking force and the compensation braking force.

[0014] As a preferred technical solution for vehicle downhill control, the downhill cruise mode is exited when the brake pedal is detected to be depressed to a set depth or the accelerator pedal is detected to be depressed.

[0015] As a preferred technical solution for vehicle downhill control, an auxiliary braking mode is also included, wherein the auxiliary braking mode includes:

[0016] When the auxiliary brake rocker switch is activated and the retarder lever is in the high position, the auxiliary brake mode is entered.

[0017] The motor is controlled to apply electric braking with maximum electric braking force, and the air brake controller is controlled to output corresponding air braking force according to the gear position of the deceleration handle.

[0018] As a preferred technical solution for vehicle downhill control, after the vehicle comes to a stop, the air brake controller continues to apply air braking while the parking controller applies parking; when the vehicle is detected to be parked, the air brake controller releases the air braking.

[0019] As a preferred technical solution for vehicle downhill control, when the accelerator is detected to be pressed, it is determined whether the vehicle needs to lift the cargo. If not, the parking brake is released; if so, the parking brake is kept in place.

[0020] As a preferred technical solution for vehicle downhill control, a safety redundancy braking mode is also included, which includes:

[0021] The system detected that braking force was required, that the maximum electric braking force provided by the motor was insufficient, and that the air brake controller was malfunctioning.

[0022] Send the maximum air braking command to the air brake valve.

[0023] As a preferred technical solution for vehicle downhill control, after sending the maximum air braking command to the air brake valve, the vehicle speed is detected in real time. When the vehicle speed is detected to be less than the set value, a parking command is sent to the parking valve.

[0024] The vehicle uses the downhill control method described in any of the above schemes.

[0025] The beneficial effects of this invention are:

[0026] This invention provides a vehicle downhill control method, including a downhill cruise mode. When the activation conditions of the downhill cruise mode are met, the vehicle enters the downhill cruise mode, and the vehicle speed at the moment of entering the downhill cruise mode is used as the set speed. The method calculates the total braking force required for the vehicle to descend the slope at the set speed. The method compares the maximum electric braking force that the motor can provide with the total braking force. When the maximum electric braking force that the motor can provide is greater than or equal to the total braking force, the method controls the motor to perform electric braking with the total braking force. When the maximum electric braking force that the motor can provide is less than the total braking force, the method controls the motor to perform electric braking with the maximum electric braking force, and controls the air brake controller to implement air braking to compensate for the electric braking. When the set speed is not high, the braking torque provided by the motor is sufficient to keep the vehicle moving at the set speed at a constant speed. At this time, there is no need to intervene with air brakes for additional deceleration. When the set speed is high, the braking torque provided by the motor is insufficient to keep the vehicle moving at the set speed at a constant speed. At this time, by intervening with air brakes, the electric brakes can be compensated, and the vehicle can be decelerated to a safe speed that the motor can maintain when going downhill at a constant speed. This avoids the risk of speeding and rolling back, and no driver intervention is required.

[0027] The present invention also provides a vehicle employing the vehicle downhill control method provided by the present invention. By employing the vehicle downhill control method improved by the present invention, the vehicle achieves a constant and stable downhill descent, avoiding the risks of speeding and rolling back, and eliminating the need for driver intervention. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the downhill cruise mode in the vehicle downhill control method provided in this embodiment of the invention.

[0029] Figure 2 This is a flowchart illustrating the auxiliary braking mode in the vehicle downhill control method provided in this embodiment of the invention.

[0030] Figure 3 This is a flowchart illustrating the safety redundancy braking mode in the vehicle downhill control method provided in this embodiment of the invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0032] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0035] like Figure 1 As shown, this embodiment of the invention provides a vehicle downhill control method, including a downhill cruise mode, which includes:

[0036] S11. When the conditions for starting the downhill cruise mode are met, the downhill cruise mode is entered, and the vehicle speed at the moment of entering the downhill cruise mode is used as the set speed.

[0037] The conditions for activating downhill cruise mode include activating the downhill cruise rocker switch, deactivating the retarder lever, releasing the accelerator pedal, releasing the brake pedal, and releasing the handbrake; or detecting that the vehicle speed increases by a set range within a set time period, such as detecting that the vehicle speed increases by 0.5-1.0 km / h within 1-2 seconds, and that the retarder lever is deactivated, the accelerator pedal is released, and the brake pedal is released.

[0038] After entering downhill cruise mode, the driver can use the speed adjustment button to increase or decrease the set speed within a range of ±3km / h.

[0039] Once downhill cruise mode is activated, the vehicle controller will issue a notification, such as sending a notification message to the instrument panel or emitting a notification sound.

[0040] S12. Calculate the total braking force required for the vehicle to descend the slope at a set speed.

[0041] Specifically, step S12 includes:

[0042] S121. The feedforward braking force is calculated based on the vehicle's longitudinal dynamics formula, the vehicle's empty and fully loaded states, and the gradient of the vehicle going downhill.

[0043] The longitudinal dynamics formula for a vehicle is: F m =F f +F t +F w

[0044] Among them, F m The component of gravity is the total weight of the vehicle, which can be calculated from the vehicle's load and tare weight. Then, based on the total weight and the slope of the downhill section, the component of the total weight, F, can be calculated. m ;F f Rolling resistance, F, can be calculated based on the total vehicle weight and the rolling resistance coefficient. f ;F w For wind resistance, since the vehicle has a large tonnage and a low speed, wind resistance can be ignored; F t As feedforward braking force, in F m and F f Once all this information is known, F can be calculated using the aforementioned vehicle longitudinal dynamics formula. t .

[0045] S122. Calculate the compensating braking force based on the difference between the set vehicle speed and the actual vehicle speed.

[0046] S123. The feedforward braking force and the compensation braking force are added together to obtain the total braking force.

[0047] The feedforward braking force may be too large or too small. By calculating the compensation braking force and adding the feedforward braking force to the compensation braking force, the feedforward braking force can be PID-regulated to obtain a more accurate total braking force.

[0048] S13. Compare the maximum electric braking force that the motor can provide with the total braking force. When the maximum electric braking force that the motor can provide is greater than or equal to the total braking force, control the motor to perform electric braking with the total braking force. When the maximum electric braking force that the motor can provide is less than the total braking force, control the motor to perform electric braking with the maximum electric braking force and control the air brake controller to implement air braking to compensate for the electric braking.

[0049] When the set speed is not high, the braking torque provided by the motor is sufficient to keep the vehicle moving at the set speed at a constant speed. At this time, there is no need to intervene with air brakes for additional deceleration. When the set speed is high, the braking torque provided by the motor is insufficient to keep the vehicle moving at the set speed at a constant speed. At this time, by intervening with air brakes, the electric brakes can be compensated, and the vehicle can be decelerated to a safe speed that the motor can maintain when going downhill at a constant speed. This avoids the risk of speeding and rolling back, and no driver intervention is required.

[0050] Furthermore, during step S13, if it is detected that the air brake controller cannot implement air braking, a maximum air braking command is directly sent to the air brake valve. It should be noted that both the air brake controller and the air brake valve can implement air braking. When the air brake controller is functioning correctly, air braking is implemented preferentially by controlling the air brake controller; when the air brake controller malfunctions, the maximum air braking is implemented by directly controlling the air brake valve, which can bring the vehicle to a stop, ensuring safe braking and avoiding the risks of speeding and rolling backwards.

[0051] S14. When the brake pedal is detected to be pressed to the set depth or the accelerator pedal is detected to be pressed, the downhill cruise mode is exited.

[0052] Furthermore, when it is detected that the brake pedal is pressed but not to the set depth, a prompt is issued to encourage the driver to press the brake pedal further until the set depth is reached. In this embodiment, the braking force required to press the brake pedal to the set depth is greater than the total braking force required for the vehicle to descend the slope at a set speed.

[0053] like Figure 2 As shown, the vehicle downhill control method provided in this embodiment of the invention further includes an auxiliary braking mode, which includes:

[0054] S21. When the auxiliary brake rocker switch is activated and the retarder lever is in the high gear, the auxiliary brake mode is entered.

[0055] S22. Control the motor to perform electric braking with maximum electric braking force, and control the air brake controller to output the corresponding air braking force according to the gear position of the deceleration handle.

[0056] By combining electric braking and air braking, the vehicle can be brought to a stop on a slope.

[0057] During step S22, if the air brake controller is detected to be unable to implement air braking, a maximum air braking command is directly sent to the air brake valve. It should be noted that both the air brake controller and the air brake valve can implement air braking. When the air brake controller is functioning correctly, air braking is implemented preferentially by controlling the air brake controller; when the air brake controller malfunctions, the maximum air braking is implemented by directly controlling the air brake valve, which can bring the vehicle to a stop and ensure safe braking.

[0058] S23. When the vehicle comes to a stop, the air brake controller continues to apply air braking, and at the same time, the parking controller applies parking. When the vehicle is detected to be parked, the air brake controller releases the air braking.

[0059] This step ensures the vehicle comes to a stable stop, preventing the risk of it rolling away.

[0060] S24. When the accelerator is detected to be pressed, determine whether the vehicle needs to lift the cargo. If not, control the parking brake to release the parking brake. If so, control the parking brake to keep the parking brake in place.

[0061] When the downhill slope is steep, the auxiliary braking mode provided in this embodiment can be activated to assist braking of the vehicle, ensure safe braking, and avoid the risk of the vehicle rolling away.

[0062] like Figure 3 As shown, the vehicle downhill control method provided in this embodiment of the invention further includes a safety redundancy braking mode, which includes:

[0063] S31. It is detected that braking force is required, and the maximum electric braking force provided by the motor is insufficient, and the air brake controller is detected to be faulty.

[0064] S32, Send the maximum air braking command to the air brake valve;

[0065] S33. Real-time detection of vehicle speed. When the vehicle speed is detected to be less than the set value, a parking command is sent to the parking valve.

[0066] When the air brake controller malfunctions, the safety redundancy braking mode provided in this embodiment can be activated to ensure safe braking of the vehicle.

[0067] This invention also provides a vehicle that employs the aforementioned vehicle downhill control method. By employing this method, the vehicle achieves a stable, uniform downhill descent, avoiding the risks of speeding and slipping, and eliminating the need for driver intervention; it also enables auxiliary braking; and it provides redundant control in case of air brake control failure, ensuring safe braking of the vehicle.

[0068] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling vehicle downhill, characterized in that, It includes downhill cruise mode, assisted braking mode, and safety redundancy braking mode, wherein the downhill cruise mode includes: When the conditions for starting the downhill cruise mode are met, the vehicle enters the downhill cruise mode and uses the vehicle speed at the moment of entering the downhill cruise mode as the set speed. Calculate the total braking force required for the vehicle to descend the slope at the set speed at a constant speed. The maximum electric braking force that the motor can provide is compared with the total braking force. When the maximum electric braking force that the motor can provide is greater than or equal to the total braking force, the motor is controlled to perform electric braking with the total braking force. When the maximum electric braking force that the motor can provide is less than the total braking force, the motor is controlled to perform electric braking with the maximum electric braking force, and the air brake controller is controlled to implement air braking to compensate for the electric braking. The auxiliary braking modes include: When the auxiliary brake rocker switch is activated and the retarder lever is in the high position, the auxiliary brake mode is entered. The motor is controlled to apply electric braking with the maximum electric braking force, and the air brake controller is controlled to output the corresponding air braking force according to the gear position of the deceleration handle. In the auxiliary braking mode, after the vehicle comes to a stop, the air brake controller continues to apply air braking, while the parking controller applies parking; when the vehicle is detected to be parked, the air brake controller releases the air braking. In the auxiliary braking mode, when the accelerator is detected to be pressed, it is determined whether the vehicle needs to lift the cargo. If not, the parking brake is released; if so, the parking brake is kept in place. The safety redundancy braking mode includes: The system detected that braking force was required, that the maximum electric braking force provided by the motor was insufficient, and that the air brake controller was malfunctioning. Send the maximum air braking command to the air brake valve.

2. The vehicle downhill control method according to claim 1, characterized in that, The activation conditions for the downhill cruise mode include activating the downhill cruise rocker switch, deactivating the deceleration lever, releasing the accelerator pedal, releasing the brake pedal, and releasing the handbrake.

3. The vehicle downhill control method according to claim 1, characterized in that, The total braking force required for a vehicle to descend a slope at a constant speed at a set speed includes: The feedforward braking force is calculated based on the vehicle's longitudinal dynamics formula, the vehicle's empty and fully loaded states, and the gradient of the downhill slope. The compensating braking force is calculated based on the difference between the set vehicle speed and the actual vehicle speed. The total braking force is obtained by adding the feedforward braking force and the compensation braking force.

4. The vehicle downhill control method according to claim 1, characterized in that, When the brake pedal is detected to be depressed to a set depth or the accelerator pedal is detected to be depressed, the downhill cruise mode is discontinued.

5. The vehicle downhill control method according to claim 1, characterized in that, In the safety redundancy braking mode, after sending the maximum air braking command to the air brake valve, the vehicle speed is detected in real time. When the vehicle speed is detected to be less than the set value, a parking command is sent to the parking valve.

6. A vehicle, characterized in that, The vehicle downhill control method according to any one of claims 1-5 is adopted.

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