Electric Fuel Pump Terminal Insulation Against Corrosion
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Solution Overview
Problem
Conventional fuel pumps experience electrochemical corrosion when exposed to gasoline-alternate fuels with high electric conductivity, as the terminals are directly exposed to the fuel, leading to potential conduction failures and breakage.
Innovation Solution
The design incorporates an insulative terminal support member with a projection and recess to increase the distance between the positive and negative electrode terminals, reducing exposure to the fuel and preventing corrosion, while resin-molding the terminals to further minimize contact with the conductive fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the terminals are arranged closer together, then the fuel pump size is reduced, but electrochemical corrosion occurs due to exposure to conductive fuel
Solution Approach 1:
The patent introduces an insulative bearing holder as an intermediary component between the terminals and the conductive fuel. This bearing holder supports the rotation axis and provides electrical insulation, preventing direct contact between the terminals and the fuel, thereby eliminating the corrosion issue while allowing compact terminal arrangement.
2Reliability
If the terminals are arranged further apart, then electrochemical corrosion is suppressed, but the fuel pump size increases
Solution Approach 1:
The patent employs a composite structure combining insulative bearing holder material with the overall pump housing. The bearing holder is made of insulative material that both supports the rotation axis and provides electrical isolation, creating a multi-functional component that prevents corrosion without increasing pump dimensions.
3Use of energy by moving object
If the terminals are fully exposed to the fuel passage, then electrical conduction is ensured, but electrochemical corrosion occurs
Solution Approach 1:
The insulative bearing holder acts as a mediator that allows the terminals to maintain their electrical conduction function while preventing harmful contact with the conductive fuel. The bearing holder's insulative property blocks the electrochemical corrosion pathway while not interfering with the electrical function of the terminals.
Solution Approach 2:
The patent applies local quality by providing insulation only where needed - specifically at the bearing holder location where the terminals are supported. This localized insulative measure prevents corrosion at the critical terminal areas without requiring complete insulation of the entire fuel passage, maintaining electrical conduction where required.
Data Source
AI summary
A fuel pump includes a case member defining a fuel passage, an inlet, and an outlet. A pump portion is provided in the fuel passage for pumping fuel from the inlet to the outlet. A motor portion is provided in the case member for driving the pump portion. A positive electrode terminal and a negative electrode terminal are provided for conducting electricity to the motor portion. A holder being insulative is provided inside the case member. The holder is mounted with the positive electrode terminal and the negative electrode terminal. The positive electrode terminal and the negative electrode terminal are resin-molded.