Hydraulic Brake Pressure Control for Jolt-Free Vehicle Stopping
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Solution Overview
Problem
Current foot-force-actuable brake systems do not offer jolt-free stopping functionality, unlike electrohydraulic systems, which lack driver feedback and are limited in their response characteristics.
Innovation Solution
A method to reduce hydraulic fluid pressures by 30% to 70% automatically based on vehicle velocity, with optional adjustments for dynamic axle load distribution, allowing for reduced pressure on front wheels during extreme braking, and complete reduction in specific brake circuits to maintain vehicle stability and driver control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulic fluid pressure is reduced by 30% to 70% based on vehicle velocity to minimize jolt, then stopping comfort is improved, but braking force is reduced
Solution Approach 1:
The brake system dynamically adjusts hydraulic fluid pressure based on real-time vehicle velocity measurements. The control device continuously monitors velocity and modulates brake pressure accordingly, transitioning from static to dynamic pressure control to optimize both comfort and braking effectiveness throughout the stopping process.
Solution Approach 2:
The system changes the physical parameter of hydraulic fluid pressure in response to changing vehicle velocity. By reducing pressure by 30% to 70% as velocity decreases, the system adapts braking force to match the vehicle's kinetic energy, providing gentle stopping at low speeds while maintaining adequate braking force at higher speeds.
2Ease of operation
If hydraulic fluid pressure is reduced to compensate for static friction, then vehicle jolt is minimized, but braking reliability may be compromised
Solution Approach 1:
The control device implements a feedback mechanism by continuously monitoring vehicle velocity and using this information to adjust hydraulic pressure. This closed-loop control ensures that pressure reduction is precisely matched to the vehicle's kinetic state, preventing over-reduction that would compromise stopping reliability while still minimizing jolt effects.
Solution Approach 2:
The system performs preliminary pressure reduction before the vehicle comes to a complete stop, anticipating the transition from kinetic to static friction. By proactively reducing pressure as velocity decreases, the system prepares the brake system for the friction transition, preventing jolt while maintaining control.
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
This approach minimizes vehicle jolt upon stopping by compensating for static friction, maintains vehicle stability, and ensures reliable braking with reduced pressure, while allowing driver control and increased pressure upon reaching a stationary state for enhanced braking force.
Implementation Method 1
the vehicle jolt that arises upon reaching the stationary state of the vehicle is at least minimized because the—compared to the sliding friction—higher static friction of the brake linings is compensated by a lower brake pressure
Data Source
AI summary
A method of stopping a motor vehicle without jolting is described, which is characterized in that a sum of the hydraulic fluid pressures generated by a foot-force-actuable brake system and acting upon the braking devices of the motor vehicle during the stopping operation is reduced in a driver-independent manner by 30% to 70% in dependence upon a variable that is related to the vehicle velocity.