Cruise control method and system for pure electric vehicle and pure electric vehicle

Abstract

This invention discloses a cruise control method, system, and vehicle for a pure electric vehicle, comprising: after the vehicle is powered on, clearing the stored target speed; after the cruise mode is activated, if the chassis components require torque control and the accelerator or brake pedal is depressed, the electric drive system enters torque control mode; if the chassis components do not require torque control and neither the accelerator nor brake pedal is depressed, determining whether the current mode is in speed control mode; if not in speed control mode, storing the current speed as the target speed and activating speed control mode to control speed at the target speed while limiting output torque; if in speed control mode, controlling speed at the target speed while limiting output torque. This invention reduces the number of buttons and simplifies operation.

Description

Technical Field

[0001] This invention belongs to the field of cruise control technology for pure electric vehicles, specifically relating to a cruise control method, system, and pure electric vehicle for pure electric vehicles. Background Technology

[0002] Cruise control systems can reduce driver fatigue at high speeds, minimizing the strain on the driver's feet. To achieve cruise control, a vehicle typically requires at least three buttons for starting / stopping it, increasing / decreasing speed. However, applying the brakes disengages cruise control, and re-engaging requires pressing a button. From the perspectives of ease of use and cost, there is an urgent need to reduce the number of buttons and simplify operation.

[0003] Therefore, it is necessary to develop a new cruise control method, system, and electric vehicle for pure electric vehicles. Summary of the Invention

[0004] The purpose of this invention is to provide a cruise control method, system, and electric vehicle for pure electric vehicles, which can reduce the number of buttons and reduce the difficulty of operation.

[0005] The present invention discloses a cruise control method for a pure electric vehicle, comprising the following steps:

[0006] Step 1: After powering on the vehicle, clear the stored target speed;

[0007] Step 2: Determine if cruise mode is activated. If not activated, repeat step 2. If activated, proceed to step 3.

[0008] Step 3: Determine if the chassis components require torque control. If so, proceed to Step 4; otherwise, proceed to Step 5.

[0009] Step 4: Without exiting cruise mode or changing the target speed, the electric drive system enters torque control mode. The chassis components calculate the corresponding torque, and the electric drive system executes according to the target torque calculated by the chassis components, then returns to step 2.

[0010] Step 5: Determine if the brake pedal is depressed. If the brake pedal is depressed, proceed to step 6. If the brake pedal is not depressed, proceed to step 7.

[0011] Step 6: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the torque, the electric drive system performs torque control according to the torque, and returns to step 2.

[0012] Step 7: Determine if the accelerator pedal is pressed. If the accelerator pedal is pressed, proceed to step 8. If the accelerator pedal is not pressed, proceed to step 9.

[0013] Step 8: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the torque, the electric drive system performs torque control according to the torque, and returns to step 2.

[0014] Step 9: Determine whether the current mode of the electric drive system is in speed control mode. If not, proceed to step 10; if yes, proceed to step 11.

[0015] Step 10: Store the current speed as the target speed, activate the speed control mode, and proceed to Step 11;

[0016] Step 11: Control the rotational speed at the target speed while limiting the output torque, and then return to step 2.

[0017] Furthermore, step 11 specifically includes:

[0018] The controller stores the optimal energy consumption speed-torque limit curves for different motor speeds. When the electric drive system is in speed control mode, the controller's output torque will be compared with the highest energy efficiency torque corresponding to the target speed under the limit of the optimal energy consumption speed-torque limit curves for different motor speeds, and the smaller limit will be selected. At the same time, the output torque will be controlled according to the preset torque change gradient.

[0019] Furthermore, the chassis components include an anti-lock braking system and a vehicle stability system.

[0020] Furthermore, the controller is a motor controller for an electric drive system, or a vehicle controller.

[0021] Secondly, the cruise control system for a pure electric vehicle according to the present invention includes:

[0022] A switch used to activate cruise mode;

[0023] Accelerator pedal;

[0024] Brake pedal;

[0025] An electric drive system used to perform torque execution according to torque commands from a controller;

[0026] Chassis components used to intervene in motor torque based on vehicle slippage;

[0027] And a controller for setting braking torque and throttle torque, which is connected to the switch, accelerator pedal, brake pedal, electric drive system and chassis components respectively;

[0028] The controller is programmed to perform the steps of the cruise control method for a pure electric vehicle as described in this invention.

[0029] Thirdly, the pure electric vehicle described in this invention employs a cruise control system as described in this invention.

[0030] The present invention has the following advantages:

[0031] (1) The present invention only requires one switch for starting / stopping the cruise control function, which reduces the need for switches to increase and decrease vehicle speed compared to the prior art.

[0032] (2) After the vehicle is powered on, the cruise mode can be activated by simply switching on the switch. During subsequent driving, the driver can control the vehicle's acceleration, deceleration or constant speed by simply using the accelerator or brake, thus reducing the number of operation steps.

[0033] (3) The present invention can also maintain the optimal energy consumption of the vehicle. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the principle of this embodiment;

[0035] Figure 2 This is a flowchart of this embodiment;

[0036] Figure 3 This is a schematic diagram illustrating the optimal efficiency constraints in this embodiment. Detailed Implementation

[0037] The invention will now be further described with reference to the accompanying drawings.

[0038] like Figure 2 As shown, a cruise control method for a pure electric vehicle includes the following steps:

[0039] Step 1: After powering on the vehicle, clear the stored target speed.

[0040] Step 2: Determine if cruise mode is activated. If not activated, repeat step 2. If activated, proceed to step 3.

[0041] Step 3: Determine if the chassis components require torque control. If so, proceed to Step 4; otherwise, proceed to Step 5.

[0042] Step 4: If the chassis components request torque intervention, such as when the vehicle slips during energy recovery on a wet surface or when climbing a slope on a wet surface, the cruise control mode is not disengaged, and the target speed is not changed. The electric drive system enters torque control mode, the chassis components calculate the corresponding torque, and the electric drive system executes the target torque calculated by the chassis components; then proceed to step 2.

[0043] Step 5: If no chassis component intervention request is received, determine whether the brake pedal is depressed. There are two types of brake pedals: one that only outputs two states (depressed (assuming an output value of "1") and not depressed (assuming an output value of "0"), and another that can output the pedal opening degree. For brake pedals with only "1" and "0" output values, a "1" value indicates the brake pedal is depressed, and a "0" value indicates it is not depressed. For brake pedals that can output the pedal opening degree, determine if the opening degree is less than a preset braking opening value (e.g., 1%). If the opening degree is greater than or equal to 1%, the brake pedal is considered depressed; if it is less than 1%, it is considered not depressed. If the brake pedal is determined to be depressed, proceed to step 6; if no chassis component intervention and braking are not initiated, proceed to step 7.

[0044] Step 6: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the energy recovery torque based on the brake pedal depth or enable signal, and the electric drive system performs torque control according to this torque, then returns to step 2.

[0045] Step 7: If the chassis components and brakes are not engaged, determine whether the accelerator pedal is depressed. There are two types of accelerator pedals: one that only outputs two states (depressed (assuming an output value of "1") and not depressed (assuming an output value of "0"), and another that can output pedal opening. For accelerator pedals with only "1" and "0" output values, if a "1" value is detected, the pedal is considered depressed; if a "0" value is detected, the pedal is considered not depressed. For accelerator pedals that can output pedal opening, determine if the opening is less than a preset accelerator opening value (e.g., 1%). If the opening is greater than or equal to 1%, the pedal is considered depressed; if the opening is less than 1%, the pedal is considered not depressed. If it is determined that the accelerator pedal is pressed, proceed to step 8. If neither the chassis intervenes nor the brakes or accelerator are pressed, proceed to step 9.

[0046] Step 8: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the torque based on the accelerator pedal depth, and the electric drive system performs torque control based on this torque. At the same time, it proceeds to step 2.

[0047] Step 9: Determine whether the current electric drive system is in speed control mode. If not, proceed to step 10; if yes, proceed to step 11.

[0048] Step 10: Store the current speed as the target speed, activate the speed control mode, and proceed to Step 11.

[0049] Step 11: Perform torque control at the target speed while limiting the output torque, and return to Step 2; specifically: the controller stores the optimal energy consumption speed-torque limiting curves (referred to as optimal efficiency curves, obtained through calibration based on the specific motor) for different motor speeds, such as... Figure 3 As shown. When in speed control mode, the controller's output torque is compared with the highest energy-efficient torque corresponding to the target speed under the constraint of the optimal efficiency curve, and the smaller value is selected as the limit to ensure that the vehicle can drive with economical energy consumption in speed control mode. At the same time, the output torque is controlled according to a preset torque change gradient to ensure driving smoothness.

[0050] In actual driving, when the vehicle moves from a flat road to an uphill slope, the output torque controlled by the electric drive system will gradually increase. If the output torque is... Figure 3 After being limited by the optimal efficiency curve 7, the vehicle speed will be forced to decrease when the output torque is insufficient. However, as the vehicle speed decreases, the torque of the limiting curve will gradually increase. Therefore, the vehicle speed will be maintained at a constant speed at a slightly lower level, so that the vehicle is balanced at the optimal driving speed and torque to maintain the cruise mode. Since the road gradient will not change suddenly, the change in vehicle speed is gradual and relatively safe for the user. At the same time, because the torque is limited, it also ensures that if the user needs to accelerate to overtake, the power system still has the ability to accelerate. After the accelerator is fully depressed, the electric drive system will output maximum torque. At this time, the output torque is only limited by the maximum speed torque curve 8 of the motor, which enables overtaking and ensures driving safety.

[0051] like Figure 1 As shown, in this embodiment, a cruise control system for a pure electric vehicle includes a switch 1, an accelerator pedal 6, a brake pedal 5, an electric drive system 3, a controller 2, and a chassis component 4. The switch 1 is used to activate the cruise mode; the switch 1 can be a button, a knob, or another human-machine interface (UI). The electric drive system 3 is used to execute torque according to the torque command from the controller 2. The chassis component 4 is used to intervene in the motor torque based on vehicle slippage. The controller 2 is responsible for setting the braking torque and throttle torque; the controller 2 is connected to the switch 1, the accelerator pedal 6, the brake pedal 5, the electric drive system 3, and the chassis component 4, respectively. The controller 2 is programmed to execute the steps of the cruise control method for a pure electric vehicle as described in this embodiment.

[0052] In this embodiment, the chassis component 4 includes an anti-lock braking system, a vehicle stability system, etc., which can intervene in the motor torque according to the wheel slippage situation to ensure vehicle safety.

[0053] In this embodiment, the controller 2 is a motor controller of the electric drive system or a vehicle controller (VCU). The control algorithm can be implemented by the motor controller of the electric drive system or the vehicle controller. If it is implemented by the motor controller, the corresponding throttle, brake and chassis signals are sent to the motor controller through the communication of the vehicle controller.

[0054] In this embodiment, a pure electric vehicle employs a cruise control system as described in this embodiment.

Claims

1. A cruise control method for a pure electric vehicle, characterized in that, Includes the following steps: Step 1: After powering on the vehicle, clear the stored target speed; Step 2: Determine if cruise mode is activated. If not activated, repeat step 2. If activated, proceed to step 3. Step 3: Determine if the chassis components require torque control. If so, proceed to Step 4; otherwise, proceed to Step 5. Step 4: Without exiting cruise mode or changing the target speed, the electric drive system enters torque control mode. The chassis components calculate the corresponding torque, and the electric drive system executes according to the target torque calculated by the chassis components, then returns to step 2. Step 5: Determine if the brake pedal is depressed. If the brake pedal is depressed, proceed to step 6. If the brake pedal is not depressed, proceed to step 7. Step 6: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the torque, the electric drive system performs torque control according to the torque, and returns to step 2. Step 7: Determine if the accelerator pedal is pressed. If the accelerator pedal is pressed, proceed to step 8. If the accelerator pedal is not pressed, proceed to step 9. Step 8: The electric drive system exits the speed control mode, clears the target speed, and enters the torque control mode. The controller calculates the torque, the electric drive system performs torque control according to the torque, and returns to step 2. Step 9: Determine whether the current mode of the electric drive system is in speed control mode. If not, proceed to step 10; if yes, proceed to step 11. Step 10: Store the current speed as the target speed, activate the speed control mode, and proceed to Step 11; Step 11: Control the rotational speed at the target speed while limiting the output torque, and then return to step 2.

2. The cruise control method for a pure electric vehicle according to claim 1, characterized in that: Step 11 specifically involves: The controller stores the optimal energy consumption speed-torque limit curves for different motor speeds. When the electric drive system is in speed control mode, the controller's output torque will be compared with the highest energy efficiency torque corresponding to the target speed under the limit of the optimal energy consumption speed-torque limit curves for different motor speeds, and the smaller limit will be selected. At the same time, the output torque will be controlled according to the preset torque change gradient.

3. The cruise control method for a pure electric vehicle according to claim 1 or 2, characterized in that: The chassis components include an anti-lock braking system and a vehicle stability system.

4. The cruise control method for a pure electric vehicle according to claim 3, characterized in that: The controller is either a motor controller for an electric drive system or a vehicle controller.

5. A cruise control system for a pure electric vehicle, comprising: Switch (1) for activating cruise mode. Accelerator pedal (6); Brake pedal (5); An electric drive system for performing torque execution according to the torque command of the controller (3); Chassis components (4) used to intervene in the motor torque according to vehicle slippage. And a controller (2) for giving braking torque and throttle torque, which is connected to a switch (1), accelerator pedal (6), brake pedal (5), electric drive system (3) and chassis components (4), respectively; The controller (2) is characterized in that it is programmed to perform the steps of the cruise control method for a pure electric vehicle as described in any one of claims 1 to 4.

6. A pure electric vehicle, characterized in that: The cruise control system for a pure electric vehicle as described in claim 5 is adopted.

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