Electric Vehicle Creep Torque Control With Autohold Stability
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Solution Overview
Problem
Existing electric vehicles lack the ability to replicate the creep behavior of conventional vehicles with internal combustion engines, which can lead to unexpected movement when stationary, and there is a need to adapt vehicle behavior to driver preferences regarding creep torque levels and autohold functions.
Innovation Solution
A method for controlling a traction electric motor to generate adjustable creep torque, which can be activated or deactivated based on driver input, including the use of a control device to manage creep torque levels and an autohold function that activates the brake system when certain conditions are met, such as incline or brake actuation, to prevent unintended movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If creep torque is generated to simulate conventional vehicle behavior, then driver familiarity and ease of operation are improved, but unexpected movement when stationary and safety risks worsen
Solution Approach 1:
The patent implements dynamic control of creep torque by allowing drivers to select between multiple creep levels (first, second, third levels) and enabling automatic deactivation when braking is detected. The system transitions between different creep torque states based on driving conditions and driver input, rather than maintaining a fixed creep behavior.
Solution Approach 2:
The patent changes the parameter of creep torque magnitude by providing multiple discrete levels (first level with higher torque, second level with moderate torque, third level with lower torque). This allows the system to adapt the creep effect intensity according to different driving situations, resolving the contradiction between providing creep behavior and preventing unintended movement.
2Device complexity
If fixed creep torque is implemented, then vehicle behavior is simplified, but adaptability to different driver preferences and conditions worsens
Solution Approach 1:
The system provides dynamic adaptability through multiple creep levels and conditional activation/deactivation based on braking detection. Drivers can choose their preferred creep level, and the system automatically adjusts behavior when braking is applied, combining simplicity with adaptability.
Solution Approach 2:
The patent makes the creep function multi-functional by providing different creep levels for different driving conditions and situations. The same creep mechanism serves multiple purposes: providing familiar vehicle behavior, allowing driver preference selection, and automatically adapting when braking is detected.
3Ease of operation
If creep torque is continuously active, then ease of movement from stationary position is improved, but energy consumption and unnecessary propulsion worsen
Solution Approach 1:
The patent implements periodic or conditional activation of creep torque rather than continuous operation. The creep function is activated based on driver selection and driving conditions, and automatically deactivated when braking is detected, creating an on-demand operation pattern that reduces energy consumption while maintaining ease of movement when needed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables electric vehicles to mimic the behavior of conventional vehicles with adjustable creep torque levels and an autohold function that prevents rolling, allowing drivers to set preferences for movement and stationary behavior, ensuring the vehicle remains stationary without continuous brake actuation.
Implementation Method 1
a traction electric motor (2), wherein the traction electric motor (2) can be controlled to generate a creep torque that causes the motor vehicle to move slowly
Implementation Method 2
A braking system of the motor vehicle is actuated
Data Source
Figure 1~2
AI summary
Method for operating a motor vehicle (1) comprising a traction electric motor (2), wherein the traction electric motor (2) is controllable to generate a creeping torque that causes the motor vehicle (1) to move slowly, wherein several creeping torques of different levels are adjustable by a user of the motor vehicle.