Vehicle Tank Venting Pump for Leak Detection and Filter Flushing
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Solution Overview
Problem
The existing tank venting systems for motor vehicles are unable to effectively utilize a pump for both filter flushing and leak testing during normal operation, as they rely on a fresh air system that may not be sufficient for venting gas through the filter.
Innovation Solution
A tank venting system with a pump fluidically interconnected between the filter and a shut-off valve connected to the fresh air system, allowing the pump to generate a flushing air stream and perform a leak test by detecting pressure changes, with the option to operate at a neutral speed to detect leaks without influencing the pressure signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pump is installed in the tank venting system to enable automated leak testing and filter flushing, then the system's diagnostic capability and maintenance functionality are improved, but the device complexity increases
Solution Approach 1:
The pump is designed to perform multiple functions: it conveys venting gas from the filter to the internal combustion engine during normal operation, generates flushing air streams for filter regeneration, and creates pressure differentials for leak testing. This multi-functionality eliminates the need for separate diagnostic and maintenance equipment, resolving the contradiction between improved reliability and reduced device complexity.
2Measurement precision
If the pump is used to generate pressure for leak testing, then the measurement precision of leak detection is improved, but the pump cannot be used for venting gas during normal operation
Solution Approach 1:
The system dynamically switches the pump's operational mode based on system needs. During normal operation, the pump conveys venting gas at appropriate flow rates. During leak testing, the pump generates controlled pressure differentials by operating in reverse or at different speeds. This dynamic adaptability allows the single pump to satisfy both productivity requirements for venting and measurement precision requirements for leak detection without permanent compromise to either function.
3Productivity
If the pump operates at high speed to convey venting gas efficiently, then the productivity of the venting system is improved, but the pump influences the pressure signal and cannot be used for leak testing
Solution Approach 1:
The system employs periodic operation where the pump alternates between conveying mode (high speed for productivity) and diagnostic mode (controlled speed for measurement). The control unit coordinates these periodic switches, ensuring that leak testing occurs during designated periods when the pump operates at speeds that do not interfere with pressure signal accuracy, while venting gas conveyance occurs during other periods at high efficiency speeds.
4Device complexity
If the filter is flushed using passive negative pressure from the fresh air system, then the device complexity is reduced, but the flushing effectiveness is insufficient compared to active pump-driven flushing
Solution Approach 1:
The pump serves as a universal component that provides both active flushing capability and maintains compatibility with passive flushing modes. When active flushing is required for reliable filter regeneration, the pump generates controlled air streams through the filter. The system design allows flexibility to use passive negative pressure from the fresh air system when conditions permit, thus achieving both flushing effectiveness and device simplicity through the pump's multi-functional design.
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 automated leak testing and filter flushing, allowing for the detection of leaks as small as 0.5 mm and facilitating maintenance by enabling reversible connections in the tank venting system, improving the system's reliability and maintenance friendliness.
Implementation Method 1
a pump (25) to generate a flushing air stream (29) in order to flush the filter (16)
Implementation Method 2
the pump or another diagnosis pump can be employed to generate a gas pressure in the fuel tank, that is to say, an excess pressure or a negative pressure in comparison to the ambient pressure
Implementation Method 3
The control unit is configured to detect a pressure signal that serves for the likewise provided leak test and that is dependent on the gas pressure present in the fuel tank
Data Source
AI summary
A tank venting system (14) for a motor vehicle (10) has a filter (16) to filter a venting gas (15) of a fuel tank (12) of the motor vehicle (10), a pump (25) to generate a flushing air stream (29) in order to flush the filter (16), and a control unit (30) that, for purposes of performing a leak test, is configured to detect a pressure signal (34) that is dependent on the gas pressure (P) present in the fuel tank (12) and to check whether the pressure signal (34) meets a prescribed leakage criterion (33). The pump (25) is fluidically interconnected between the filter (16) and a shut-off valve (26), whereby the shut-off valve (26) is configured to fluidically couple the pump (25) to an inlet site (27) of a fresh air system (19) of an internal combustion engine (11) of the motor vehicle (10), and whereby the control unit (30) is configured to operate the pump (25) for flushing the filter (16) as well as for performing the leak test.