Brake-By-Wire Diagnostic Valve for Leak-Tightness Checks
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Solution Overview
Problem
Existing brake-by-wire systems require additional structural space and electromagnetic actuation for comprehensive leak-tightness checks, which is inefficient and costly.
Innovation Solution
Incorporating a diagnostic valve composed of a check valve and a restrictor in the connection between the reservoir and the master brake cylinder, allowing for hydraulic operation without electromagnetic actuation, enabling a throttled pressure dissipation gradient for leak-tightness assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnetically actuated diagnostic valve is used to check leak-tightness, then comprehensive leak-tightness check is enabled, but additional structural space and electromagnetic actuation are required
Solution Approach 1:
The diagnostic function is merged into the existing check valve by adding a restrictor element to the connection between the reservoir and master brake cylinder. This combines the leak-tightness checking capability with the existing hydraulic connection, eliminating the need for a separate electromagnetic diagnostic valve and its actuation system.
Solution Approach 2:
The electromagnetic actuation system is extracted and removed from the diagnostic function. Instead of using an electromagnetically actuated valve, the patent uses a purely mechanical/hydraulic solution with a check valve and restrictor, eliminating the need for electrical components and electromagnetic actuation.
2Measurement precision
If the restrictor cross section is made narrow for reliable diagnosis, then measurement precision is improved, but pressure medium flow rate is reduced
Solution Approach 1:
The check valve acts as an intermediary element that allows pressure medium to flow from the reservoir to the master brake cylinder during normal operation, but restricts and controls the reverse flow during diagnostic mode. The restrictor within the check valve provides a known flow resistance that enables precise measurement of pressure dissipation while maintaining adequate flow capability.
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 reliable leak-tightness checks with minimal additional valve outlay, eliminating the need for electromagnetic actuation and reducing structural complexity, while maintaining system functionality.
Implementation Method 1
a check valve, which blocks in the direction of the reservoir
Implementation Method 2
a restrictor connected in parallel with respect to said check valve... this takes place relatively slowly, such that it can be stated that the brake system is functional if the gradient of the brake pressure dissipation corresponds to the selected restrictor cross section
Data Source
AI summary
To check the functionality/leak-tightness of a brake-by-wire brake system, a motor-operated brake pressure transducer is actuated. In this case, a pressure medium would flow out into a reservoir via a master brake cylinder. A diagnostic valve is therefore provided between the master brake cylinder and the reservoir, which diagnostic valve is composed of a check valve and a restrictor connected in parallel with respect to the check valve. The outflow of pressure medium is limited by the restrictor. Because the gradient of the pressure dissipation can be calculated, a measured pressure build-up can be compared with that which is to be expected, and a determination of functionality/leak-tightness can be derived from the comparison.