Brake Circuit Fault Detection via Closed Fluid Line Pressure Build-up
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Solution Overview
Problem
Current brake circuit failure identification methods in vehicles, particularly in electric and hybrid vehicles, cannot differentiate between various error states such as leaks or issues in the active pressure supply, leading to inadequate safety measures.
Innovation Solution
A method that creates a closed fluid line circuit within the brake system, using active and passive pressure build-up and iterative valve operations to determine specific fault conditions, allowing for wheel-specific error differentiation and appropriate countermeasures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor is used to detect brake circuit failures, then failure detection capability is improved, but the ability to differentiate between specific error states (leak location, pressure supply issues) deteriorates
Solution Approach 1:
The brake circuit is divided into multiple segments (first brake circuit and second brake circuit) with separate monitoring. Pressure sensors are placed at different locations to independently monitor each segment, enabling identification of which specific segment has failed while maintaining overall system reliability.
Solution Approach 2:
A control unit acts as an intermediary that receives pressure data from multiple sensors and processes this information to differentiate between various error states. The control unit analyzes pressure changes in response to valve operations to determine whether the failure is due to a leak, pressure supply issue, or sensor malfunction.
2Loss of energy
If the rear axle brake circuit is decoupled from the brake pedal for regenerative braking, then energy recovery efficiency is improved, but functional safety monitoring becomes more difficult
Solution Approach 1:
Pressure sensors in the decoupled brake circuit provide continuous feedback to the control unit. The control unit monitors pressure changes and can detect failures even though the circuit is decoupled from the brake pedal, ensuring functional safety is maintained while allowing regenerative braking operation.
Solution Approach 2:
Pressure sensors are pre-installed in the brake circuits before decoupling occurs. This preliminary placement of monitoring devices ensures that when the rear axle brake circuit is decoupled for regenerative braking, the system is already equipped to detect and report failures, maintaining safety without compromising energy recovery.
3Measurement precision
If iterative valve operations and active pressure build-up are performed for fault diagnosis, then error state differentiation precision is improved, but system complexity and diagnostic time increase
Solution Approach 1:
The diagnostic system dynamically operates valves and pressure build-up mechanisms in sequence based on detected pressure anomalies. Rather than continuously operating all components, the system adaptively activates specific valves and pressure sources only when needed to differentiate between specific error states, reducing overall complexity while maintaining precision.
Solution Approach 2:
The diagnostic process uses periodic valve operations and pressure build-up cycles to systematically test different circuit segments. By repeating standardized sequences of valve opening/closing and pressure application, the system achieves reliable error state differentiation through a structured, manageable process rather than complex continuous monitoring.
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
Enables precise identification of faults in the brake circuit, enhancing driving safety by allowing for situation-specific responses to errors, whether due to leaks or active pressure supply issues.
Implementation Method 1
When there is a pressure drop in the brake system, by creating a closed fluid line circuit (16) within the brake system and iterative active or passive pressure build-up
Data Source
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AI summary
The method involves determining whether a fluid pressure loss in the brake circuit is present. The fluid connection to a hydraulic unit and to the inlet valves (60,70) of to-be braked wheels of the vehicle are closed upon detection of a pressure loss so that a closed fluid system is generated. The generation of a pressure build-up in the closed fluid system is tried by a volume conveying unit. The generation of pressure build-up in the closed fluid system is ascertained. An independent claim is included for a brake system of a vehicle.