Downstream Fuel Filter with Flow Restriction for Low-Temp Clogging
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Solution Overview
Problem
In pressure accumulation fuel injection systems, fuel filters located upstream of the feed pump experience low fuel pressure, leading to clogging and insufficient flow rates due to increased fuel viscosity at low temperatures, and those located downstream occupy excessive space due to larger sizes.
Innovation Solution
A fuel supply device with a fuel filter positioned downstream of the feed pump, where a positive pressure from the feed pump prevents clogging and a flow rate restricting device upstream of the suction quantity control valve maintains a restricted flow rate, reducing the filter's size and required installation space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel filter is located upstream of the feed pump, then the fuel filter experiences low fuel pressure, but this causes clogging and insufficient flow rate when fuel viscosity increases at low temperatures
Solution Approach 1:
The patent inverts the conventional arrangement by placing the fuel filter downstream of the feed pump instead of upstream. This reversal allows the filter to operate under positive pressure conditions, preventing clogging and ensuring sufficient fuel flow rate even when viscosity increases at low temperatures, while maintaining reliable fuel supply to the high-pressure pump.
2Reliability
If the fuel filter is located downstream of the feed pump, then the passing pressure of the fuel filter increases, but the body size of the fuel filter increases requiring more installation space
Solution Approach 1:
The patent changes the operating pressure parameter of the fuel filter by relocating it downstream of the feed pump. This parameter change allows the filter to operate under positive pressure, improving its filtering performance and preventing clogging. The increased pressure differential across the filter enhances its ability to remove contaminants while maintaining a compact size suitable for tight engine spaces.
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 configuration enhances the reliability and longevity of the fuel injection system by preventing clogging and ensuring sufficient fuel supply, while minimizing the space needed for the fuel filter, thus addressing both clogging and space constraints.
Implementation Method 1
Since the fuel filter is located downstream of the feed pump, a positive pressure of the feed pump is applied to the fuel filter. Accordingly, a passing pressure of the fuel filter increases
Implementation Method 2
The fuel filter is located between the feed pump and the suction control valve to filter the fuel discharged by the feed pump
Implementation Method 3
The flow rate restricting device is located upstream of the suction quantity control valve to restrict a flow rate of the fuel passing through the fuel filter
Data Source
AI summary
A fuel filter is located downstream of a feed pump to filter fuel discharged from the feed pump. An orifice is located between the fuel filter and a suction quantity control valve to restrict a flow rate of the fuel passing through the fuel filter. A positive pressure of the feed pump is applied to the fuel filter, and a passing pressure at the fuel filter increases. Even if viscosity of the fuel increases and the fuel becomes wax-like at low temperature, clogging of the fuel filter or an insufficient flow rate can be inhibited. The orifice restricts the flow rate of the fuel passing through the fuel filter. Accordingly, an increase in size of the fuel filter can be prevented even if the fuel filter is located downstream of the feed pump.