Method for realizing lock-up function of pure electric heavy truck in manual mode of transmission

Abstract

The application provides a method for realizing the locking function of a pure electric heavy truck in a manual mode of a transmission, related hardware includes a vehicle controller and a driving motor; the method comprises the following steps: when the vehicle controller detects that the transmission is switched to the manual mode, the wheel edge torque C is calculated first, then the motor demand torque is calculated according to the locking function enabling condition and whether the locking function enabling condition is established or not according to the corresponding strategy. The application has the beneficial technical effects that the method for realizing the locking function of the pure electric heavy truck in the manual mode of the transmission is provided, the scheme can prevent the forced gear shifting of the transmission, and the driving safety and comfort are improved.

Description

Technical Field

[0001] This invention relates to a control technology for pure electric heavy-duty trucks, and more particularly to a method for implementing a gear locking function in the manual mode of a pure electric heavy-duty truck. Background Technology

[0002] Based on existing technology, it is known that pure electric heavy-duty trucks under heavy load will generally switch the transmission to manual mode when going uphill or downhill to avoid power loss caused by frequent gear shifting. During vehicle acceleration, the motor speed continuously increases. When the motor speed approaches the maximum motor speed, the transmission will force a gear shift. Forced gear shifting poses certain safety hazards. In addition, the gear shifting process will cause a power interruption, especially under the aforementioned heavy-load uphill conditions. This phenomenon will be amplified and, in severe cases, will cause vehicle vibration, which is detrimental to driving comfort. Summary of the Invention

[0003] The technical problem to be solved by this invention is to avoid the problem of forced gear shifting caused by continuous acceleration in the manual mode of the transmission of pure electric heavy trucks under heavy load.

[0004] The technical solution of this invention is:

[0005] A method for implementing a gear-locking function in manual mode of a pure electric heavy-duty truck, involving hardware including a vehicle controller and a drive motor; its innovation lies in: the method includes:

[0006] When the vehicle controller detects that the transmission has switched to manual mode, proceed as follows:

[0007] 1) Using the set speed A as the target speed, set the target angular acceleration B of the motor based on the difference between the actual motor speed and A; in order to make the actual angular acceleration of the motor reach B, the required torque C of the wheel side is calculated using a PID algorithm;

[0008] The set speed A is less than the upshift speed threshold of the transmission in the current gear;

[0009] 2) Determine if all five locking function enable conditions are met: If all five locking function enable conditions are met, proceed to step 3); otherwise, return to step 1).

[0010] The five locking functions are enabled under the following conditions: the transmission is in manual mode, the motor speed is greater than the threshold E, the brake opening is less than the threshold F, the handbrake is not engaged, and the transmission is not in the process of shifting gears.

[0011] The reason for using a motor speed greater than a threshold E as the enable condition for the aforementioned five gear locking functions is that the purpose of this invention is to enable the gear locking function in any gear position. This requires that the motor should not be forced to shift gears because its speed is close to the maximum speed of the motor. Therefore, a threshold E is set so that we can control the motor speed between the threshold E and the set speed A.

[0012] The reason for using a brake opening less than the threshold F as the condition for enabling the gear locking function is that the purpose of applying the brake is to decelerate, which, when mapped to the motor, means reducing torque output or even outputting negative torque. However, in this invention, maintaining the rotational speed is actually outputting positive torque. Therefore, the gear locking function is not executed when the brake opening is greater than or equal to the threshold F.

[0013] 3) Assign the locking torque value to C; continue to determine whether the two locking torque execution conditions are met: if either of the two locking torque execution conditions is met, proceed to step 4); if neither of the two locking torque execution conditions is met, proceed to step 5).

[0014] The two locking torque execution conditions are as follows:

[0015] 1. The vehicle is in forward gear, the throttle opening is greater than the threshold H, and the wheel-side torque demand C is less than the driver's torque demand I;

[0016] 2. The vehicle is in reverse gear, and the throttle opening is greater than the threshold H, and the wheel-side torque demand C is greater than the driver's torque demand I.

[0017] If the first locking torque execution condition is met, it means that the motor is rotating forward in D gear and outputting positive torque. The wheel-side torque calculated by the locking function is less than the torque required by the driver, meaning that the motor speed needs to be controlled to stop increasing. If the second locking torque execution condition is met, it means that the motor is rotating backward in R gear and outputting negative torque. The wheel-side torque calculated by the locking function is greater than the torque required by the driver, meaning that the motor speed needs to be controlled to stop increasing negatively.

[0018] 4) Calculate the required torque of the motor based on the lock-up adjustment torque and the transmission ratio, and control the drive motor according to the required torque; at this time, the required torque of the motor = lock-up adjustment torque ÷ transmission ratio;

[0019] 5) Calculate the required torque of the motor based on the driver's required torque and the transmission ratio, and control the drive motor according to the required torque of the motor; at this time, the required torque of the motor = the required torque of the driver ÷ the transmission ratio.

[0020] By adopting the aforementioned solution, while ensuring safe driving, it is possible to prevent the transmission from being forced to shift gears due to continuous acceleration in manual mode, which can effectively improve driving safety and driving comfort.

[0021] Preferably, the set rotational speed A is in the range of 2600 to 2650 rpm.

[0022] Preferably, the target angular acceleration B of the motor is in the range of -15 to 15 rad / s². 2 .

[0023] Preferably, the threshold E is in the range of 2500 to 2550 rpm.

[0024] Preferably, the threshold F ranges from 3 to 5%, and the threshold H ranges from 3 to 5%.

[0025] The aforementioned numerical ranges are the optimal ranges obtained from actual vehicle road tests. Combined with the technical solution of this invention, they can effectively ensure driving safety and comfort.

[0026] The beneficial technical effects of this invention are: it proposes a method for implementing a gear locking function in the manual mode of a pure electric heavy truck, which can prevent forced gear shifting and improve driving safety and comfort. Detailed Implementation

[0027] A method for implementing a gear-locking function in manual mode of a pure electric heavy-duty truck, involving hardware including a vehicle controller and a drive motor; its innovation lies in: the method includes:

[0028] When the vehicle controller detects that the transmission has switched to manual mode, proceed as follows:

[0029] 1) Using the set speed A as the target speed, set the target angular acceleration B of the motor based on the difference between the actual motor speed and A; in order to make the actual angular acceleration of the motor reach B, the required torque C of the wheel side is calculated using a PID algorithm;

[0030] The set speed A is less than the upshift speed threshold of the transmission in the current gear;

[0031] 2) Determine if all five locking function enable conditions are met: If all five locking function enable conditions are met, proceed to step 3); otherwise, return to step 1).

[0032] The five locking functions are enabled under the following conditions: the transmission is in manual mode, the motor speed is greater than the threshold E, the brake opening is less than the threshold F, the handbrake is not engaged, and the transmission is not in the process of shifting gears.

[0033] 3) Assign the locking torque value to C; continue to determine whether the two locking torque execution conditions are met: if either of the two locking torque execution conditions is met, proceed to step 4); if neither of the two locking torque execution conditions is met, proceed to step 5).

[0034] The two locking torque execution conditions are as follows:

[0035] 1. The vehicle is in forward gear, the throttle opening is greater than the threshold H, and the wheel-side torque demand C is less than the driver's torque demand I;

[0036] 2. The vehicle is in reverse gear, and the throttle opening is greater than the threshold H, and the wheel-side torque demand C is greater than the driver's torque demand I;

[0037] 4) Calculate the required torque of the motor based on the lock-up adjustment torque and the transmission ratio, and control the drive motor according to the required torque; at this time, the required torque of the motor = lock-up adjustment torque ÷ transmission ratio;

[0038] 5) Calculate the required torque of the motor based on the driver's required torque and the transmission ratio, and control the drive motor according to the required torque of the motor; at this time, the required torque of the motor = the required torque of the driver ÷ the transmission ratio.

[0039] Furthermore, the set rotational speed A is in the range of 2600 to 2650 rpm.

[0040] Furthermore, the target angular acceleration B of the motor ranges from -15 to 15 rad / s². 2 .

[0041] Furthermore, the threshold E ranges from 2500 to 2550 rpm.

[0042] Furthermore, the threshold F ranges from 3 to 5%, and the threshold H ranges from 3 to 5%.

Claims

1. A method for implementing a gear-locking function in manual mode of a pure electric heavy-duty truck, the hardware involved including a vehicle controller and a drive motor; characterized in that: The method includes: When the vehicle controller detects that the transmission has switched to manual mode, proceed as follows: 1) Using the set speed A as the target speed, set the target angular acceleration B of the motor based on the difference between the actual motor speed and A; in order to make the actual angular acceleration of the motor reach B, the required torque C of the wheel side is calculated using a PID algorithm; The set speed A is less than the upshift speed threshold of the transmission in the current gear; 2) Determine if all five locking function enable conditions are met: If all five locking function enable conditions are met, proceed to step 3); otherwise, return to step 1). The five locking functions are enabled under the following conditions: the transmission is in manual mode, the motor speed is greater than the threshold E, the brake opening is less than the threshold F, the handbrake is not engaged, and the transmission is not in the process of shifting gears. 3) Assign the locking torque value to C; continue to determine whether the two locking torque execution conditions are met: if either of the two locking torque execution conditions is met, proceed to step 4); if neither of the two locking torque execution conditions is met, proceed to step 5). The two locking torque execution conditions are as follows:

1. The vehicle is in forward gear, the throttle opening is greater than the threshold H, and the wheel-side torque demand C is less than the driver's torque demand I; 2. The vehicle is in reverse gear, and the throttle opening is greater than the threshold H, and the wheel-side torque demand C is greater than the driver's torque demand I; 4) Calculate the required torque of the motor based on the lock-up adjustment torque and the transmission ratio, and control the drive motor according to the required torque; at this time, the required torque of the motor = lock-up adjustment torque ÷ transmission ratio; 5) Calculate the required torque of the motor based on the driver's required torque and the transmission ratio, and control the drive motor according to the required torque of the motor; at this time, the required torque of the motor = the required torque of the driver ÷ the transmission ratio.

2. The method for implementing gear locking function in manual mode of a pure electric heavy-duty truck according to claim 1, characterized in that: The set rotational speed A is in the range of 2600 to 2650 rpm.

3. The method for implementing gear locking function in manual mode of a pure electric heavy-duty truck according to claim 1, characterized in that: The target angular acceleration B of the motor ranges from -15 to 15 rad / s². 2 .

4. The method for implementing gear locking function in manual mode of a pure electric heavy-duty truck according to claim 1, characterized in that: The threshold E ranges from 2500 to 2550 rpm.

5. The method for implementing gear locking function in manual mode of transmission for a pure electric heavy-duty truck according to claim 1, characterized in that: The threshold F ranges from 3 to 5%, and the threshold H ranges from 3 to 5%.