Active Steering Synchronization During Auto-Stop Events
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Solution Overview
Problem
The challenge in implementing start-stop technology in vehicles is synchronizing the steering system during low power situations, especially on low-friction surfaces, where the Active Front Steering (AFS) motor cannot adjust the drive angle to match the steering wheel angle due to insufficient energy, leading to potential steering mismatches.
Innovation Solution
A controller powers an electrical actuator coupled to the steering mechanism to synchronize the drive angle and steering wheel angle when a wheel slip event is detected and the steering-wheel angle exceeds a threshold, ensuring proper alignment and operation during auto-stop and auto-start events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the AFS motor is stopped or frozen during auto-stop events to save energy, then fuel economy is improved, but steering wheel and drive angle synchronization is lost
Solution Approach 1:
The controller detects wheel slip events in advance and proactively powers the AFS motor before steering angle mismatch becomes critical, maintaining synchronization between the steering wheel and drive angle during low-friction surface conditions
Solution Approach 2:
The system continuously monitors wheel slip parameters and steering angle differential, using this feedback to determine when to activate the AFS motor during auto-stop events, ensuring synchronization is maintained only when necessary
2Stability of the object's composition
If the AFS motor is frozen to hold wheel position during auto-stop, then vehicle stability is improved, but steering responsiveness and angle matching deteriorate
Solution Approach 1:
The system dynamically adjusts the AFS motor state based on real-time conditions, transitioning between frozen and active states according to detected wheel slip events and steering angle differentials, optimizing both stability and responsiveness
3Object-generated harmful factors
If the engine auto-stops to reduce emissions, then emissions performance is improved, but steering system power availability decreases
Solution Approach 1:
The controller prepares the AFS motor by powering it in advance upon detecting wheel slip conditions, ensuring sufficient power availability before steering adjustments are needed during engine off periods
Solution Approach 2:
The system uses vehicle operational parameters (wheel slip detection, steering angle monitoring) to autonomously manage AFS motor power state, eliminating the need for continuous external power input while maintaining steering functionality
Data Source
AI summary
A vehicle is provided. The vehicle may include an engine that is configured to auto-stop and auto-start. The system may also include a controller programmed to power an electrical actuator coupled to a steering mechanism to synchronize a drive angle of the vehicle and a steering wheel angle of the vehicle, in response to a parameter indicative of a likelihood of a wheel slip event exceeding a threshold and the steering-wheel angle being greater than a predetermined threshold.