Fuel Tank System Leak Testing via Compressor Permeability
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Solution Overview
Problem
Current fuel tank systems for internal combustion engines lack a comprehensive method to check the tightness of the entire system, particularly beyond the section between the tank ventilation valve and the check valve, which is crucial to prevent uncontrolled escape of fuel vapors into the environment.
Innovation Solution
A fuel tank system incorporating a vane compressor with defined gas permeability, integrated shut-off valves, and pressure sensors allows for the generation and measurement of pneumatic pressure across sections to determine tightness, enabling the detection of leaks and ensuring the system's overall integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is arranged between the tank ventilation valve and the check valve to diagnose the tank ventilation system, then the tightness of the tank ventilation system in the section between the tank ventilation valve and the check valve can be inferred, but it is not possible to check the tightness of the remaining sections of the tank ventilation system
Solution Approach 1:
The scavenging air line is divided into two separate testable sections by introducing a shut-off valve. The first section extends from the fuel vapor filter to the shut-off valve, and the second section extends from the shut-off valve to the compressor. This segmentation allows independent tightness testing of each section, enabling comprehensive system-wide tightness checking while maintaining measurement precision in each segment.
2Object-affected harmful factors
If the scavenging air line is emptied of fuel vapors by means of a compressor after the internal combustion engine has been switched off, then fuel vapors are prevented from escaping via the fresh gas line into the environment, but there is no method to check the overall tightness of the fuel tank system
Solution Approach 1:
The shut-off valve is positioned to enable preliminary isolation of test sections before tightness testing. This allows the system to prepare test sections in advance by closing the shut-off valve, isolating the first and second sections, and then performing pressure change measurements to detect leaks before actual operation occurs.
Solution Approach 2:
A pressure sensor provides feedback on pressure changes within isolated sections of the scavenging air line. By monitoring pressure changes after isolating sections with the shut-off valve, the system receives feedback that indicates whether leaks are present, enabling reliable tightness verification of the entire fuel tank system including previously uncheckable sections.
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 solution allows for the effective testing of the fuel tank system's tightness, identifying both significant and small leaks, and ensuring the system remains leak-proof, thereby adhering to emission regulations by preventing fuel vapor escape.
Implementation Method 1
A fuel tank system incorporating a vane compressor with defined gas permeability, integrated shut-off valves, and pressure sensors allows for the generation and measurement of pneumatic pressure across sections to determine tightness
Implementation Method 2
A fuel tank system incorporating a vane compressor with defined gas permeability, integrated shut-off valves, and pressure sensors allows for the generation and measurement of pneumatic pressure across sections to determine tightness
Data Source
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AI summary
A fuel tank system having - a fuel tank (10), - a fuel vapour filter (14), which is fluidically connected to an opening into the environment (62), - a breather line (12) leading from the fuel tank (10) to the fuel vapour filter (14), - a scavenging air line (16) leading from the fuel vapour filter (14) to a fresh gas line (18) of the internal combustion engine, - a compressor (64) integrated into the scavenging air line (16) and - a shut-off valve (60) integrated into the scavenging air line (16), which valve is arranged between an opening (50) of the scavenging air line (16) into the fresh gas line (18) and the compressor (64), is characterised in that a specified gas permeability is implemented for the compressor (64) in the event that it is not operating. A fuel tank system of this kind makes an advantageous testing of the leak-tightness of the fuel tank system possible, in that a specified pneumatic pressure is generated in at least one section of the scavenging air line (16) centrally encompassing the compressor (64), which section is specifically closed against the inflow and outflow of a gas, and then a distinction is made between an adequate and inadequate leak-tightness of this section on the basis of a change in this pressure.