EV Donut Mode Torque Control for AWD Traction Limits
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Solution Overview
Problem
Performing a donut maneuver on an all-wheel drive vehicle is challenging due to traction limits and elevated differentials on front and rear axles, making it difficult for inexperienced drivers.
Innovation Solution
A vehicle system with a motor, steering wheel, instrument panel, and controller enables a donut mode by delivering torque differentially to the rear wheels, allowing speed differentiation and steering input to create a donut pattern, with conditions like battery charge, steering direction, and ground level ensuring safe execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque is delivered to all wheels in an all-wheel drive vehicle, then traction is improved, but it becomes difficult to perform donut maneuvers due to elevated differentials on front and rear axles
Solution Approach 1:
The patent segments the torque distribution by disabling the front axle and directing torque exclusively to the rear wheels. The controller isolates the rear axle from the front axle, allowing independent control of rear wheel torque while the front wheels remain stationary or rotate minimally, enabling the donut maneuver without the restraint of front axle differential limitations
Solution Approach 2:
The system dynamically adjusts torque distribution based on the selected maneuver mode. When donut mode is activated, the controller dynamically redirects torque flow from the front axle to the rear axle, creating a dynamic reconfiguration of the all-wheel drive system that prioritizes rear-wheel torque for the donut maneuver
2Adaptability or versatility
If torque is delivered to rear wheels for donut maneuver, then donut capability is improved, but vehicle control complexity increases due to multiple conditions to satisfy
Solution Approach 1:
The system performs preliminary actions by checking multiple vehicle conditions (battery charge level, steering wheel position, brake status, gear selection) before enabling donut mode. The controller validates these conditions in advance and provides user interface guidance to ensure the vehicle is properly prepared, preventing premature or unsafe activation of the maneuver
Solution Approach 2:
The system implements feedback through the user interface menu that displays the current status of each condition required for donut mode. The controller continuously monitors vehicle state and provides real-time feedback to the driver about which conditions are satisfied and which need to be addressed before the maneuver can be executed
Data Source
AI summary
A vehicle system and method for a vehicle implements a donut mode to vehicle wheels for creating a donut. A motor provides drive torque to at least one wheel of the vehicle wheels for propelling the vehicle. A steering wheel communicates a steering wheel signal indicative of a direction intended for the vehicle to travel. An instrument panel cluster displays a user interface menu that includes a user selectable donut mode. The controller initiates a donut mode based on user selection of the donut mode. The controller determines whether vehicle conditions are satisfied and enables torque to be delivered from the motor to the left and right rear wheels. Speed differential is enabled between the left and right rear wheels and the left and right front wheels. Based on a direction of the steering wheel, a desired torque input is determined to one of the left and right rear wheels.