New energy commercial vehicle variable speed oil pump control method and system

Abstract

The invention relates to a new energy commercial vehicle variable speed oil pump control method and system, and the method comprises the steps: judging whether a current vehicle needs to enable a power-assisted steering motor or not according to the operation state and the vehicle speed state of a vehicle control unit VCU; the power-assisted steering motor enters a working state, and whether the current vehicle has the power-assisted steering requirement or not is judged according to the hand brake state, the transmission gear state and the vehicle speed state; when the current vehicle has no power-assisted steering requirement, the power-assisted steering motor works at the lowest rotating speed; when the current vehicle has the power-assisted steering requirement, the power-assisted steering motor works at the target rotating speed; on the premise that the cost of the whole vehicle is not increased, the rotating speed of the motor of the vehicle power-assisted steering system can be automatically adjusted, the power consumption of the steering system is reduced when steering is not needed, meanwhile, it is guaranteed that assistance is provided in time when steering is needed, the change of steering hand feeling under the high-speed and low-speed working conditions is reduced, and wider working condition adaptability is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a variable speed oil pump control method and system for a new energy commercial vehicle. Background Art

[0002] In the electric hydraulic power steering system commonly used in new energy heavy-duty trucks, the power of the power steering oil pump comes from the power steering motor (i.e., EHDS motor). The control method of this motor is generally to work at a set speed after the vehicle controller VCU issues an enable command. There are only two states: no rotation and fixed speed to provide power for steering wheel rotation; however, there are the following problems:

[0003] 1. The power steering motor starts to work at the rated speed after the vehicle's high-voltage circuit is connected. When the vehicle is in a static park and does not require steering, although the steering system load is low, there is still work waste in the power steering motor.

[0004] 2. The steering wheel rotation resistance of the whole vehicle is closely related to the current vehicle speed. The resistance that needs to be overcome in a stationary state is the greatest. As the vehicle speed increases, the steering wheel becomes easier to turn. Therefore, the power steering motor works at a fixed speed and cannot balance the steering power demand in situ and the power demand at high speeds, resulting in a large change in driving feel. Summary of the invention

[0005] The purpose of the present invention is to provide a variable speed oil pump control method and system for a new energy commercial vehicle in view of the deficiencies in the prior art.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A variable speed oil pump control method and system for a new energy commercial vehicle, the method comprising:

[0008] According to the running status of the vehicle controller VCU and the vehicle speed status, determine whether the current vehicle needs to enable the power steering motor;

[0009] The power steering motor enters the working state and determines whether the current vehicle needs power steering according to the handbrake state, transmission gear state and vehicle speed state;

[0010] When the vehicle has no steering assistance requirement, the steering assistance motor operates at the lowest speed;

[0011] When the vehicle currently requires power steering, the power steering motor operates at the target speed.

[0012] As a further explanation of the invention, judging whether the current vehicle needs to enable the power steering motor according to the operating state of the vehicle controller VCU and the vehicle speed state; including:

[0013] Get the running state of the vehicle controller VCU. When the running state of the vehicle controller VCU is the upper high voltage state, the power steering motor enters the working state;

[0014] The vehicle speed status is obtained. When the vehicle speed is ≥ the motion speed threshold, the power steering motor enters the working state.

[0015] As a further explanation of the invention, the power steering motor enters a working state, and determines whether the current vehicle has a power steering demand according to the handbrake state, the transmission gear state and the vehicle speed state; including:

[0016] Get the handbrake status, transmission gear status and vehicle speed status;

[0017] When the handbrake is in the pulled-up state, the transmission gear is in neutral, and the vehicle speed is less than the sports speed threshold, when the three conditions are met at the same time, it is judged that the current vehicle has no steering assistance demand; when one of the three conditions is not met, it is judged that the current vehicle has a steering assistance demand.

[0018] As a further explanation of the invention, when there is no steering assistance requirement for the current vehicle, the steering assistance motor operates at the lowest speed; including:

[0019] When there is no steering assistance requirement for the current vehicle, the steering assistance motor operates at a non-zero minimum speed.

[0020] As a further explanation of the invention, when the current vehicle has a steering assist demand, the steering assist motor operates at a target speed; including:

[0021] Get the current vehicle speed status; adjust the target speed according to the vehicle speed-steering power motor speed MAP.

[0022] As a further illustration of the invention, when the current vehicle changes from having no steering assistance demand to having steering assistance demand, the steering assistance motor automatically adjusts to the target speed at a non-zero minimum speed.

[0023] A variable speed oil pump control system for a new energy commercial vehicle, the system comprising a vehicle controller VCU, a power steering motor, a power steering oil pump, a four-in-one controller, a handbrake switch, a gearbox, an instrument and a steering wheel;

[0024] The handbrake switch, the gearbox and the instrument are respectively connected to the vehicle controller VCU, the vehicle controller VCU is connected to the four-in-one controller, the four-in-one controller is connected to the power steering motor, the power steering motor provides power for the power steering oil pump, and the power steering oil pump provides power for steering the steering wheel.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention recognizes that when the vehicle has no steering demand, the steering power motor drives the steering power oil pump at a non-zero minimum stable operating speed; when the vehicle has a steering demand, the steering power motor adjusts the target speed according to the vehicle speed-steering power motor speed MAP, so as to keep the steering feel in line with the driving demand; the present invention realizes automatic adjustment of the motor speed of the vehicle steering power system without increasing the cost of the entire vehicle, reduces the power consumption of the steering system when there is no steering demand, and ensures timely provision of assistance when steering is required, further reduces the change of steering feel under high and low vehicle speed conditions, and has a wider range of adaptability to working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic flow chart of the method of the present invention;

[0028] Figure 2 It is a schematic diagram of the system principle of the present invention;

[0029] Figure 3 It is a schematic diagram of the vehicle speed-steering power motor speed MAP curve law of the present invention. DETAILED DESCRIPTION

[0030] like Figure 1-3 As shown, a variable speed oil pump control method for a new energy commercial vehicle includes:

[0031] According to the running status of the vehicle controller VCU and the vehicle speed status, determine whether the current vehicle needs to enable the power steering motor;

[0032] The power steering motor enters the working state and determines whether the current vehicle needs power steering according to the handbrake state, transmission gear state and vehicle speed state;

[0033] When the vehicle has no steering assistance requirement, the steering assistance motor operates at the lowest speed;

[0034] When the vehicle currently requires steering assistance, the steering assistance motor operates at the target speed; in this way, the motor speed is reduced to reduce idling power consumption when static parking does not require steering assistance. When steering is required, the motor speed is gradually adjusted according to the vehicle speed to maintain a stable steering wheel assistance torque without obvious fluctuations. This can reduce the power consumption of the steering system and improve the situation where the steering feel of the steering wheel changes greatly at high and low speeds.

[0035] According to the running status of the vehicle controller VCU and the vehicle speed status, it is determined whether the current vehicle needs to enable the power steering motor; including:

[0036] Get the running state of the vehicle controller VCU. When the running state of the vehicle controller VCU is the upper high voltage state, the power steering motor enters the working state;

[0037] The vehicle speed status is obtained. When the vehicle speed is ≥ the motion speed threshold, the power steering motor enters the working state.

[0038] The power steering motor enters the working state and determines whether the current vehicle needs power steering according to the handbrake state, transmission gear state and vehicle speed state; including:

[0039] Get the handbrake status, transmission gear status and vehicle speed status;

[0040] When the handbrake is in the pulled-up state, the transmission gear is in neutral, and the vehicle speed is less than the sports speed threshold, when the three conditions are met at the same time, it is judged that the current vehicle has no steering assistance demand; when one of the three conditions is not met, it is judged that the current vehicle has a steering assistance demand.

[0041] When the vehicle has no steering assistance requirement, the steering assistance motor operates at the lowest speed; including:

[0042] When there is no steering assistance requirement for the current vehicle, the steering assistance motor operates at a non-zero minimum speed.

[0043] When the vehicle has a steering assist requirement, the steering assist motor operates at the target speed; including:

[0044] Get the current vehicle speed state; adjust the target speed according to the vehicle speed-steering power motor speed MAP. The vehicle speed-steering power motor speed MAP is obtained based on the vehicle speed-steering power motor speed MAP curve. The curve rule is that low vehicle speed requires high speed, and as the vehicle speed increases, the speed value gradually decreases; after the motor reaches the set maximum speed, the speed no longer increases.

[0045] When the vehicle changes from no steering assistance demand to steering assistance demand, the steering assistance motor automatically adjusts to the target speed at a non-zero minimum speed to ensure that the steering wheel does not get stuck when it is just turned, and the steering wheel turning feel does not change significantly as the vehicle speed increases.

[0046] A variable speed oil pump control system for new energy commercial vehicles, the system includes a vehicle controller VCU, a power steering motor, a power steering oil pump, a four-in-one controller, a handbrake switch, a gearbox, an instrument and a steering wheel;

[0047] The handbrake switch, gearbox and instrument are connected to the vehicle controller VCU respectively, the vehicle controller VCU is connected to the four-in-one controller, the four-in-one controller is connected to the power steering motor, the power steering motor provides power for the power steering oil pump, and the power steering oil pump provides power for steering the steering wheel. The handbrake switch, gearbox and instrument send three related signals of handbrake status, transmission gear status and vehicle speed status to the vehicle controller VCU respectively. The vehicle controller VCU receives the three related signals, calculates and determines whether the current vehicle has a power steering demand. When the current vehicle has a power steering demand, the speed control command is sent to the four-in-one controller through the CAN signal. The four-in-one controller controls the speed of the power steering motor according to this signal, thereby providing power for the power steering oil pump, and the power steering oil pump provides power for steering the steering wheel.

Claims

1. A variable speed oil pump control method for a new energy commercial vehicle, characterized in that: The method comprises: According to the running status of the vehicle controller VCU and the vehicle speed status, determine whether the current vehicle needs to enable the power steering motor; The power steering motor enters the working state and determines whether the current vehicle needs power steering according to the handbrake state, transmission gear state and vehicle speed state; When the vehicle has no steering assistance requirement, the steering assistance motor operates at the lowest speed; When the vehicle currently requires power steering, the power steering motor operates at the target speed.

2. The variable speed oil pump control method for new energy commercial vehicles according to claim 1, characterized in that: According to the running status of the vehicle controller VCU and the vehicle speed status, it is determined whether the current vehicle needs to enable the power steering motor; including: Get the running state of the vehicle controller VCU. When the running state of the vehicle controller VCU is the upper high voltage state, the power steering motor enters the working state; The vehicle speed status is obtained. When the vehicle speed is ≥ the motion speed threshold, the power steering motor enters the working state.

3. The variable speed oil pump control method for new energy commercial vehicles according to claim 2, characterized in that: The power steering motor enters a working state, and determines whether the current vehicle has a power steering demand according to the handbrake state, the transmission gear state and the vehicle speed state; including: Get the handbrake status, transmission gear status and vehicle speed status; When the handbrake is in the pulled-up state, the transmission gear is in neutral, and the vehicle speed is less than the sports speed threshold, when the three conditions are met at the same time, it is judged that the current vehicle has no steering assistance demand; when one of the three conditions is not met, it is judged that the current vehicle has a steering assistance demand.

4. The variable speed oil pump control method for new energy commercial vehicles as claimed in claim 3, characterized in that: When the vehicle has no steering assistance requirement, the steering assistance motor operates at the lowest speed; including: When there is no steering assistance requirement for the current vehicle, the steering assistance motor operates at a non-zero minimum speed.

5. The variable speed oil pump control method for new energy commercial vehicles according to claim 4, characterized in that: When the vehicle has a steering assist requirement, the steering assist motor operates at the target speed; including: Get the current vehicle speed status; adjust the target speed according to the vehicle speed-steering power motor speed MAP.

6. The variable speed oil pump control method for new energy commercial vehicles as claimed in claim 5, characterized in that: When the current vehicle changes from no steering assistance demand to a steering assistance demand, the steering assistance motor automatically adjusts to the target speed at a non-zero minimum speed.

7. A variable speed oil pump control system for a new energy commercial vehicle, comprising a variable speed oil pump control method for a new energy commercial vehicle as claimed in any one of claims 1 to 6, characterized in that: The system includes a vehicle controller VCU, a power steering motor, a power steering oil pump, a four-in-one controller, a handbrake switch, a gearbox, an instrument panel and a steering wheel; The handbrake switch, the gearbox and the instrument are respectively connected to the vehicle controller VCU, the vehicle controller VCU is connected to the four-in-one controller, the four-in-one controller is connected to the power steering motor, the power steering motor provides power for the power steering oil pump, and the power steering oil pump provides power for steering the steering wheel.

Images