Vehicle Control Unit for Anti-Rollback During Auto Stop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current automatic switch-off systems for internal combustion engines in vehicles do not adequately prevent undesired vehicle motion during the switch-off process, particularly when the driver attempts to change their mind and continue moving before the vehicle has reached a standstill, leading to potential rolling back.
Innovation Solution
A control unit that initiates the automatic switch-off process before the vehicle reaches a standstill by acquiring signals indicating imminent stoppage and inability of the engine to self-sustain, and locks in a suitable brake pressure to prevent rollback, using a combination of speed, slope, and brake pedal release signals to ensure safe standstill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the automatic switch-off process is initiated before the vehicle reaches standstill, then the motor shaking is concealed with a stopping jerk and the switch-off timing is optimized, but the vehicle is no longer secured against rolling back when the driver releases the brake pedal
Solution Approach 1:
The control unit applies preliminary anti-action by detecting the switch-off process initiation and preemptively applying braking force before the vehicle reaches standstill. This prevents the harmful effect of rollback by counteracting gravitational force on inclined surfaces before the drive machine loses its self-sustaining capability
Solution Approach 2:
The control unit performs preliminary action by activating the braking system in advance during the switch-off process. The braking force is applied before the vehicle actually reaches standstill, ensuring the vehicle is secured against rolling back when the driver releases the brake pedal and the drive machine can no longer operate in a self-sustaining manner
2Reliability
If the brake pressure is locked in during the automatic switch-off process, then the vehicle is secured against rolling back, but the brake system must maintain additional pressure load
Solution Approach 1:
The control unit applies dynamics by continuously monitoring vehicle speed, slope, and drive machine operation status to dynamically adjust brake pressure. The braking force is locked in only when necessary (during switch-off process on inclined surfaces) and released when conditions change, optimizing energy usage while maintaining vehicle stability
Data Source
AI summary
A method and a corresponding device are provided for preventing an undesired vehicle motion during an automatic switch-off process of a drive machine in a motor vehicle. An automatic switch-off process is initiated by a start-stop apparatus before the standstill is reached if the motor vehicle is braked because of a deceleration request and the speed of the vehicle is less than a specified first speed threshold. A brake pressure of suitable magnitude is caused to be locked-in in the brake system even before the vehicle reaches the standstill if a first signal indicating that the vehicle standstill will soon be reached and a second signal indicating that an inability of the drive machine to operate in a self-sustaining manner will soon be reached are acquired because of an initiated automatic switch-off process of the drive machine.