Low Pressure Fuel Pump Water Detection in Diesel Systems
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Solution Overview
Problem
Water in diesel fuel can lead to reduced engine performance and degradation of high pressure fuel pumps and fuel injectors, as existing water separators may not provide timely indication of water reaching the high pressure fuel pump.
Innovation Solution
Activating a low pressure fuel pump downstream of a water separator to determine the presence of water by measuring the time it takes for pressure to reach a threshold, providing early notification of water in the fuel system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a water separator is installed to remove water from fuel, then water removal function is improved, but the separator cannot provide timely indication that water may pass through and reach the high pressure fuel pump
Solution Approach 1:
A low pressure fuel pump is introduced as an intermediary component between the water separator and the high pressure fuel pump. This intermediary pump enables the detection system to measure pressure build-up time, which serves as an indicator of water presence in the fuel. The intermediary pump allows the system to detect water passage before it reaches the high pressure fuel pump, thus providing timely warning while maintaining the water separation function.
2Measurement precision
If the water separator uses a sensor to indicate water amount in the reservoir, then water detection is provided, but it takes substantial time for the separator to indicate water mixed in fuel and advise vehicle service
Solution Approach 1:
The system performs preliminary detection by measuring the pressure build-up time in the low pressure fuel pump line before water reaches the high pressure fuel pump. This preliminary action allows the system to detect water presence earlier than traditional sensors that only monitor the water reservoir. By detecting water in the fuel stream before it reaches critical components, the system reduces the time delay in providing water contamination warnings.
3Device complexity
If no detection system is used beyond the water separator sensor, then the system remains simple, but water may pass through the separator and reach the high pressure fuel pump causing degradation
Solution Approach 1:
The system replaces complex mechanical water detection methods with a pressure-based detection approach. By measuring the pressure build-up time in the low pressure fuel pump line, the system can detect water presence using simple pressure sensors and timing logic. This mechanical substitution approach provides effective water detection and protection against fuel pump degradation while maintaining relatively simple system architecture.
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 approach reduces the risk of engine and fuel system degradation by providing early detection of water, improving water level estimation, and detecting diesel exhaust fluid in the fuel system, thereby allowing for timely vehicle service.
Implementation Method 1
determining an amount of time for a pressure downstream of the fuel pump to reach a threshold pressure
Data Source
AI summary
A method for determining the presence of water and diesel exhaust fluid mixed with diesel fuel is disclosed. In one example, output pressure of a fuel pump may be indicative of the presence or absence of water in diesel fuel. The presence or absence of water in fuel may be evaluated in response to filling a fuel tank.