Braking System Leakage Detection via Valve Actuation Segmentation
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Solution Overview
Problem
Conventional methods fail to accurately determine hydraulic leakage in motor vehicle braking systems, especially during dynamic braking actions, due to the continuous changes in brake circuit elasticity caused by high-frequency valve actuations, making it difficult to distinguish between intended volume losses and actual leakage.
Innovation Solution
The method involves calculating leakage by considering valve actuation, using the difference between actual and setpoint hydraulic volumes, and accounting for volume losses caused by discharge valve actuations, with the aid of sensors and the Bernoulli/Darcy-Weisbach equation, to precisely detect undesirable leakage during dynamic braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If discharge valves are actuated at high frequency to maintain driving stability during dynamic braking, then braking stability is improved, but the ability to accurately determine leakage is worsened due to continuous changes in brake circuit elasticity
Solution Approach 1:
The patent segments the volume change measurement into two distinct components: intended volume loss (VOV) from valve actuation and actual leakage (Vleak). By separately calculating and subtracting the intended volume loss from the total observed volume change, the system can accurately determine actual leakage even during high-frequency valve actuation. This segmentation resolves the contradiction by allowing continuous valve operation for stability while maintaining precise leakage detection capability.
2Device complexity
If conventional hydraulic volume monitoring methods are used during dynamic braking, then system simplicity is maintained, but leakage detection accuracy deteriorates due to oscillations in the braking system
Solution Approach 1:
The patent applies preliminary action by pre-calculating the intended volume loss (VOV) based on known valve actuation parameters and characteristics before determining actual leakage. By having this reference value ready and subtracting it from the total volume change, the system achieves accurate leakage measurement without requiring complex real-time filtering or analysis during dynamic braking operations.
3Reliability
If the hydraulic piston is moved further over time to compensate for leakage, then pressure generation capability is maintained, but the indication of increasing leakage is lost in the overall volume changes during valve actuation
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual leakage volume (Vleak) after separating it from intended volume loss, and using this information to trigger alerts or warnings when leakage exceeds predetermined thresholds. This feedback mechanism allows the system to maintain pressure generation reliability through piston compensation while simultaneously providing continuous information about leakage status, preventing information loss during valve actuation.
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 reliable and precise leakage detection even during active brake interventions, enhancing the reliability of the braking system by promptly identifying critical leaks and maintaining driving stability.
Implementation Method 1
When using a pressure generator including a displaceable hydraulic piston for pressure generation
Implementation Method 2
with the aid of sensors and the Bernoulli/Darcy-Weisbach equation
Implementation Method 3
with the aid of sensors and the Bernoulli/Darcy-Weisbach equation
Data Source
AI summary
A method for ascertaining a leakage in a hydraulic braking system of a motor vehicle, the braking system including at least one hydraulically actuatable wheel brake, at least one pressure generator and at least one discharge valve which is assigned to the wheel brake and actuated as a function of a driving situation of the motor vehicle to maintain driving stability, and a hydraulic volume of the braking system being monitored. It is provided that the leakage is ascertained as a function of the ascertained hydraulic volume and as a function of an actuation of the discharge valve.