Brake Pressure Channel Isolation for Leak-Tolerant Deceleration
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Solution Overview
Problem
Existing brake systems in commercial vehicles face challenges in reliably detecting leaks in pressure lines, which lead to degradation of braking power and safety risks, especially at higher levels of automation.
Innovation Solution
A method for controlling a brake system with multiple modulators, involving leak detection and localization through test control signals, and adaptive pressure control to maintain high braking performance by isolating affected pressure lines and compensating for deceleration losses using additional pressure channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure lines are monitored for leaks using conventional methods, then leak detection capability is provided, but braking performance degrades when a leak is detected due to shutdown of affected sections
Solution Approach 1:
The brake system is divided into multiple independent pressure channels, each with its own modulator and pressure medium supply. When a leak is detected in one channel, only that specific channel is isolated while other channels remain operational, maintaining overall braking capability.
Solution Approach 2:
The system continuously monitors pressure lines for leaks using test control signals before critical failures occur. By detecting leaks early and isolating them promptly, the system prevents total brake failure and maintains braking performance through proactive fault management.
2Reliability
If a leak is detected in a pressure line downstream of a modulator, then safety risks are identified, but pressure medium escapes from the supply affecting other pressure channels
Solution Approach 1:
Each pressure channel has its own dedicated pressure medium supply and modulator, creating isolated segments. A leak in one segment does not affect the pressure medium supply of other segments, preventing cascading failures and pressure medium loss across the entire system.
Solution Approach 2:
The affected pressure line with the leak is isolated and disconnected from the pressure medium supply using isolation valves. This extracts the problematic segment from the system, preventing pressure medium escape while maintaining operation of healthy segments.
3Loss of substance
If the affected pressure channel is shut down to stop pressure medium escape, then pressure medium loss is prevented, but deceleration performance is reduced
Solution Approach 1:
The brake system operates with multiple independent pressure channels. When one channel is shut down to prevent pressure medium loss, other channels remain active and can compensate for the lost deceleration performance, maintaining overall braking effectiveness.
Solution Approach 2:
The control unit adjusts the working pressure in remaining operational channels to compensate for the shutdown channel. By increasing pressure parameters in healthy channels, the system maintains required deceleration performance despite losing one pressure channel.
Data Source
AI summary
A method is for controlling a brake system having at least two modulators. A pressure can be modulated via the respective modulator and provided at a connection. The method includes: determining if there is a leak; localizing a detected leak by controlling a modulator with a test signal to change the pressure, and determining a deviation between a target value specified as a function of the signal and an actual value assigned to the connection; if a threshold is exceeded, the line has a leak; controlling a modulator so a flow connection is interrupted between the leaky line and the pressure supply from which the pressure for the connection is modulated; and at a connection to which no line with a located leak is connected, an adjusted pressure is provided, dependent on the braking demand and a deceleration loss from the interruption of the flow connection to the leaky line.