Brake Pressure Hold Control During Shift Out of Park
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Solution Overview
Problem
Existing vehicle systems fail to adequately manage brake pressure when shifting out of park, particularly on inclined surfaces, leading to potential vehicle rolling and unnecessary wear of the parking brake.
Innovation Solution
A vehicle control system that includes a hold controller to dynamically adjust brake pressure based on vehicle status and operator intent, applying a temporary augmenting brake force when shifting out of park to prevent rolling and minimize brake wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the driver applies less force to the brake pedal when shifting out of park, then the ease of operation is improved, but the vehicle stability deteriorates causing unintended movement on inclined surfaces
Solution Approach 1:
The system performs preliminary action by automatically applying service brake pressure before and during the gear shift operation. The controller detects when the gear selector is moved from park and proactively applies brake pressure to maintain vehicle stability, eliminating the need for the driver to manually apply sufficient brake force and preventing unintended movement during the transition.
2Stability of the object's composition
If the service brake remains applied during shift out of park, then the vehicle stability is improved, but the loss of time increases due to extended brake application
Solution Approach 1:
The system applies dynamics by dynamically adjusting brake pressure based on real-time vehicle conditions. The controller monitors gear selector position, brake pedal input, and vehicle motion status to modulate brake pressure - applying it when needed during the shift transition and automatically releasing it once the vehicle is stable in the new gear position, thereby minimizing unnecessary brake application time while maintaining stability during critical moments.
3Stability of the object's composition
If the parking brake pads remain applied during unnecessary shifts, then the vehicle stability is improved, but the loss of substance increases due to brake pad wear
Solution Approach 1:
The system introduces an intermediary mechanism by using the service brake system as a mediator between the driver's shift action and the parking brake. The service brake temporarily assumes the load-holding function during gear transitions, allowing the parking brake to release or remain inactive, thereby preventing unnecessary wear on parking brake pads while maintaining vehicle stability throughout the shift operation.
Data Source
AI summary
A method for controlling brake pressure during a shift of a vehicle out of park may include determining that a first status condition is met when the vehicle is in park with an electric parking brake applied, determining that a second status condition is met when the vehicle is not moving, responsive to detecting a shift of the vehicle out of park when the first and second status conditions are both met, directing a build-up of brake pressure until a brake pressure target is reached, and holding the brake pressure at the brake pressure target until a release condition is met.