Brake Fluid Cross-Flow for Rapid Pressure Build-Up
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Solution Overview
Problem
In electronically controlled hydraulic brake systems, rapid and real-time pressure build-up is crucial during dynamic situations, but adding hardware like high-pressure accumulators increases packaging space, weight, and cost, necessitating a method to leverage existing components for efficient pressure distribution.
Innovation Solution
The electronic control unit redirects brake fluid from a wheel brake already under high pressure to another wheel brake in need of pressure increase, while the pump supplements pressure, allowing for quick pressure build-up without additional hardware, prioritizing algorithms like ARP over ESC during rollover risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-pressure accumulators are added to provide fluid pressure quickly during active braking operations, then the pressure build-up speed is improved, but the packaging space, weight, and price increase
Solution Approach 1:
The brake system uses its own existing high-pressure brake fluid from active wheel brakes to rapidly pressurize wheels requiring intervention, eliminating the need for external high-pressure accumulators. The system serves itself by redirecting fluid from wheels under ESC control to wheels requiring ARP intervention.
Solution Approach 2:
The brake fluid circulation system is made multi-functional by enabling cross-wheel fluid transfer. The same brake circuit that normally operates independently for each wheel is made capable of sharing high-pressure fluid between wheels, allowing the system to serve both normal braking and emergency intervention functions.
2Speed
If high-pressure accumulators are added to provide fluid pressure quickly during active braking operations, then the pressure build-up speed is improved, but the packaging space, weight, and price increase
Solution Approach 1:
The brake system uses its own existing high-pressure brake fluid from active wheel brakes to rapidly pressurize wheels requiring intervention, eliminating the need for external high-pressure accumulators. The system serves itself by redirecting fluid from wheels under ESC control to wheels requiring ARP intervention.
Solution Approach 2:
The brake fluid circulation system is made multi-functional by enabling cross-wheel fluid transfer. The same brake circuit that normally operates independently for each wheel is made capable of sharing high-pressure fluid between wheels, allowing the system to serve both normal braking and emergency intervention functions.
3Device complexity
If the pump is used alone to build up pressure in wheel brakes during active braking operations, then the system complexity is kept low, but the pressure build-up time increases
Solution Approach 1:
The invention uses hydraulic principles to transfer high-pressure brake fluid from one wheel brake circuit to another through controlled valve operations. This hydraulic cross-feed mechanism enables rapid pressure build-up without requiring mechanical modifications to the pump or addition of pneumatic components.
Solution Approach 2:
The system dynamically adjusts brake fluid distribution based on real-time wheel speed and pressure conditions. The control unit continuously monitors wheel behavior and dynamically redirects fluid flow to prioritize wheels requiring intervention, enabling adaptive rapid response without fixed mechanical configurations.
4Speed
If brake fluid is redirected from one wheel brake to another during active braking operations, then the pressure distribution speed is improved, but the control complexity increases
Solution Approach 1:
The control unit continuously monitors wheel speed, brake pressure, and vehicle dynamics to determine when and where to redirect brake fluid. This feedback mechanism enables intelligent, real-time decisions about fluid distribution, prioritizing wheels requiring intervention while maintaining system stability through closed-loop control.
Solution Approach 2:
The electronic control unit acts as an intermediary that coordinates between different brake control algorithms (ESC and ARP). It mediates the conflict between maintaining vehicle stability through ESC and preventing rollover through ARP by intelligently managing brake fluid distribution to satisfy both control objectives.
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 enables rapid pressure distribution within the brake circuit, enhancing real-time performance and stability during dynamic maneuvers without increasing system weight or cost, effectively managing pressure demands across wheel brakes.
Implementation Method 1
If the electronic control unit decides that, within a brake circuit, one wheel brake needs a pressure increase and the other wheel brake of the same brake circuit is already under high pressure, it will be beneficial to connect the wheel brake presently under high pressure with the wheel brake needing a pressure build-up through the inlet valves, so the pressure fluid can flow across
Implementation Method 2
At the same time, the pump will supply additional brake fluid to further build up the pressure in the prioritized wheel
Data Source
AI summary
In an unstable driving situation of a vehicle with an electronically controlled hydraulic brake system with a front/rear split of brake circuits, for instance during a lane change, the inlet valve of one of the two front wheel brakes may be closed for the ESC in order to raise the pressure in only the other wheel brake of the brake circuit. If then the vehicle runs the risk of tipping over, ARP sets in. The vehicle path needs to be readjusted to reduce lateral forces. The ARP demands a pressure build-up in the curve-outer front wheel brake. The corresponding inlet valve will be opened for the ARP to allow a pressure build-up. However, the ESC may still demand a higher pressure on the initially actuated wheel brake to counter understeering. In this event, the inlet valve of the curve-inner wheel brake, which is under high pressure from the ESC intervention, will remain open to allow a cross-flow of brake fluid from the ESC wheel to the ARP wheel.