Fuel Filter Clogging Prevention via Recirculated Fuel Suction
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Solution Overview
Problem
The existing fuel supply systems face challenges in reducing filter clogging due to solidified fuel without increasing the number of parts, complicating the structure, or elevating recirculated fuel pressure, especially when filters are positioned after fuel pumps.
Innovation Solution
A fuel supply apparatus is designed with a filter placed between an electric pump and a mechanical pump, where a branch passage connects the recirculation passage to the filter inlet, and a control unit reduces the electric pump's discharge to generate suction pressure for the mechanical pump, allowing high-temperature recirculated fuel to melt solidified fuel without increasing pressure or adding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the filter is disposed at an outlet of a fuel pump, then the filter can be positioned in the fuel supply path, but the pressure of fuel discharged by the fuel pump is higher than that of recirculated fuel, making it difficult to introduce the recirculated fuel toward the filter
Solution Approach 1:
Instead of trying to push high-pressure recirculated fuel against the filter's suction pressure, the invention reverses the approach by having the electric pump create negative pressure (suction) at the filter inlet. This allows the recirculated fuel to be naturally drawn into the filter without requiring high pressure, effectively solving the pressure differential problem by working in the opposite direction of the traditional push-based system.
2Ease of operation
If the recirculated fuel pressure is increased to introduce fuel into the filter, then the fuel can be introduced into the filter, but the pressure resistance of pipes and parts increases
Solution Approach 1:
The invention replaces the mechanical push-based pressure system with an electrically-driven suction system. The electric pump generates negative pressure through electromagnetic forces, eliminating the need to increase recirculated fuel pressure mechanically. This substitution allows fuel to be introduced into the filter without increasing pressure resistance in pipes and parts.
3Reliability
If a heater is used to heat the solidified fuel, then the solidified fuel can be melted, but a heat source, electric power source, and electric leads are needed, increasing the number of parts
Solution Approach 1:
The invention makes the recirculated fuel serve a dual function: it returns to the fuel tank for cooling and simultaneously flows through the filter to melt solidified fuel. The fuel itself becomes the heating medium, eliminating the need for separate heaters, heat sources, and associated electrical components. This self-service approach prevents filter clogging while maintaining system simplicity.
4Ease of operation
If the fuel quantity discharged from the electric pump is reduced, then suction pressure is generated at the inlet portion of the mechanical pump to introduce recirculated fuel into the filter, but the fuel supply quantity may be insufficient
Solution Approach 1:
The invention dynamically adjusts the electric pump's discharge quantity based on operating conditions. By controlling the electric pump to operate at variable flow rates, the system can reduce discharge to create suction pressure for filter recirculation when needed, while maintaining adequate overall fuel supply. This dynamic control resolves the contradiction between creating suction pressure and maintaining fuel supply quantity.
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 effectively reduces filter clogging by introducing high-temperature fuel without raising recirculated fuel pressure or heating the filter, maintaining a simple structure and part count, and ensuring continuous fuel supply through bypass passages when needed.
Implementation Method 1
If the fuel quantity discharged from the electric pump is decreased, a suction pressure is generated at an inlet portion of the mechanical pump. Thereby, the fuel recirculated from the branch passage to the fuel tank is introduced into the filter.
Implementation Method 2
a relatively high temperature fuel which should be recirculated into the fuel tank is introduced into the filter so that the solidified fuel causing a clogging of the filter is melted
Data Source
AI summary
An ECU reduces a fuel flow rate discharged from an electric pump to the filter when a fuel temperature and a fuel pressure in the filter detected by a sensor portion drop. Since a mechanical pump continues to be driven without respect to the fuel quantity discharged from the electric pumps when the fuel flow rate discharged from the electric pump is decreased, a suction pressure is generated at an inlet of the filter. The fuel in a recirculation passage is introduced into the filter through a branch passage. As the result, relatively high temperature fuel is introduced into the filter to melt a solidified fuel causing a clogging of the filter.