Fuel Supply System Leak Testing via Sequential Pressure Segmentation
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Solution Overview
Problem
Current methods for testing the leak-tightness of fuel supply systems in motor vehicles are inadequate, particularly in preventing the escape of gaseous fuel constituents, which is a regulatory requirement, and existing solutions are cumbersome or inefficient in detecting leaks.
Innovation Solution
A method involving a gas-conveying device to generate differential pressures in the fuel tank and volume-changing element, with shut-off valves controlling these pressures to determine leak-tightness by monitoring pressure thresholds over time, allowing for sequential and selective testing of system components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a volume-changing element is provided in the fuel tank to compensate for pressure changes, then the tank can maintain pressure equilibrium and reduce emissions, but the complexity of the fuel supply system increases due to additional components and testing requirements
Solution Approach 1:
The leak-tightness test is segmented into multiple sequential phases: first testing the fuel tank without the volume-changing element, then testing the volume-changing element separately. This segmentation allows each component to be tested independently, simplifying the overall testing process despite the system's complexity
Solution Approach 2:
The testing method dynamically adapts to the system's configuration by sequentially isolating and testing different components. The gas-conveying device dynamically adjusts pressure conditions based on which component is being tested, making the testing process flexible rather than rigid
2Measurement precision
If sequential pressure testing is performed on both the fuel tank and volume-changing element, then accurate leak detection is achieved, but the testing time and process complexity increase
Solution Approach 1:
The fuel tank is tested for leak-tightness before the volume-changing element is connected and activated. This preliminary action ensures that the tank itself is leak-free before adding the complexity of the volume-changing element, streamlining the overall testing sequence
Solution Approach 2:
The method skips unnecessary intermediate steps by directly transitioning between testing phases. After confirming the tank is leak-tight, the system immediately proceeds to test the volume-changing element, eliminating redundant waiting or adjustment periods
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 method effectively identifies leaks in the fuel supply system, ensuring compliance with regulatory standards by accurately determining the leak-tightness of both the tank and volume-changing element, thereby preventing fuel vapor emissions.
Implementation Method 1
a differential pressure in relation to the surroundings is generated in the tank interior space with the volume-changing element shut off with respect to the surroundings, and b) a differential pressure in relation to ambient pressure is generated in the volume-changing element
Data Source
AI summary
A method for testing the tightness of a fuel supply system of a motor vehicle is provided. The fuel supply system includes a volume-changing element provided in the fuel tank, the volume of which volume-changing element is in contact with the environment. The fuel tank is customarily sealed off against the environment by way of a valve unit. For testing the tightness, a differential pressure with respect to environment is generated in the tank by way of a gas conveying device, sequentially and thus not simultaneously, the volume-changing element being sealed off against the environment, and the volume-changing element not being sealed off against the environment, a differential pressure with respect to environmental pressure is generated in the volume-changing element or in the tank. The differential pressures are maintained and monitored over a certain period of time, and if after this period of time, the differential pressures still exceed a certain threshold value, a sufficient tightness of the fuel supply system is concluded.