Wheel Slip Control via Measured Brake Fluid Volume
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Solution Overview
Problem
Existing motor vehicle braking systems require multiple iterations to achieve desired brake pressure, disrupting driving behavior and increasing braking distance due to inaccuracies in brake fluid management during wheel slip control.
Innovation Solution
A method and system that supply a first measured quantity of brake fluid to a wheel brake device, determine wheel slip, and adjust a second measured quantity based on actual changes in brake fluid volume and braking effect, rather than relying on predefined characteristic curves, to precisely control wheel slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a defined modeled characteristic curve is used to determine brake fluid quantity, then the braking system can operate with standard control logic, but multiple iterations are necessary to achieve desired brake pressure, increasing braking distance
Solution Approach 1:
The patent implements a feedback mechanism where the actual brake fluid volume in the brake device is measured and compared with the target volume. Based on this feedback, the control unit adjusts the brake fluid quantity in real-time, enabling precise control of wheel slip without requiring multiple iterative adjustments. This closed-loop control significantly reduces braking distance while maintaining accurate slip control.
2Ease of operation
If brake fluid quantity is determined based on a defined modeled characteristic curve, then the control system can function with standard algorithms, but the control requires multiple iteration steps that disrupt driving behavior
Solution Approach 1:
The patent replaces the traditional mechanical/hydraulic estimation method (based on modeled characteristic curves) with an electronic sensing and control system. A sensor directly measures the brake fluid volume in the brake device, and an electronic control unit processes this information to precisely control brake fluid quantity. This substitution eliminates the need for iterative control algorithms while ensuring consistent and reliable braking behavior.
3Adaptability or versatility
If multiple iteration steps are used to achieve desired brake pressure, then the system can adjust to varying conditions, but the braking distance increases and driving behavior is disrupted
Solution Approach 1:
The patent employs preliminary action by pre-determining the target brake fluid volume based on the desired wheel slip control objectives before the braking intervention begins. The control unit calculates the exact amount of brake fluid needed to achieve the target pressure, eliminating the need for multiple iterative adjustments during the braking process. This pre-planned approach maintains adaptability while significantly reducing braking distance.
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 allows for faster and more precise control of wheel slip, reducing braking distance and enhancing driving stability, particularly in ESP and RSC systems by minimizing control iterations and adapting to changing conditions.
Implementation Method 1
a sensor configured to detect a quantity of brake fluid used by the modulation cylinder
Implementation Method 2
a brake fluid flow control device configured to control the flow of brake fluid from the modulation cylinder to the brake device
Implementation Method 3
to brake the wheel... determine the wheel slip of the wheel... measure a change in a measure of a braking effect
Data Source
AI summary
Methods for controlling wheel slip of a motor vehicle include braking the wheel by supplying a first measured quantity of brake fluid from a modulation cylinder to a brake device of the wheel, determining the wheel slip of the wheel, and moving a second measured quantity of brake fluid between the modulation cylinder and the brake device. When the wheel slip is too small or too large, a change in a volume of the brake fluid in the modulation cylinder is measured and a change in a measure of a braking effect is determined. The second measured quantity of brake fluid is determined on the basis of the measured change in the volume of the brake fluid in the modulation cylinder and the change in the measure of the braking effect. Braking systems configured to carry out the methods, as well as vehicles including the braking systems, are further contemplated.