Fuel Pump Plastic Sealing for Electronics Protection
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Solution Overview
Problem
Existing fuel pump sealing technologies using metal-glass feedthroughs are complex, costly, and prone to leaks due to thermal expansion issues and brittleness, making them unsuitable for cost-effective and long-term protection of pump electronics.
Innovation Solution
The use of plastic as a sealing material for the metal housing of fuel pumps, where only 2% of the surface area has reduced tightness, allowing fuel vapor entry without damaging electronics, and the design includes plastic injection molding for secure electrical connections and embossing for secure placement, reducing production complexity and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass bushings are used to seal electrical connections in metal housing, then hermetic sealing is achieved, but production complexity and costs increase due to high temperature requirements and precision needs
Solution Approach 1:
The patent replaces expensive glass bushings with inexpensive plastic seals that are easier to manufacture and install. The plastic seals achieve sufficient protection for electronics without requiring the high hermetic standards of glass, thereby reducing production complexity and costs while maintaining adequate reliability for the application.
Solution Approach 2:
The patent changes the material parameter from glass to plastic, which has lower melting temperature and different sealing requirements. This allows sealing to occur at lower temperatures that are compatible with electronic component tolerances, and simplifies the sealing process by eliminating the need for high-precision alignment and specialized glass processing equipment.
2Reliability
If glass bushings are used for sealing, then hermetic tightness is achieved, but handling problems occur due to brittleness
Solution Approach 1:
The patent replaces fragile glass bushings with durable plastic seals that are resistant to impact and handling damage. Plastic materials provide sufficient toughness for assembly and service operations while maintaining adequate sealing performance, eliminating the brittleness issues associated with glass components.
3Reliability
If metal-glass sealing is used, then high tightness is achieved, but thermal expansion differences cause leaks over service life
Solution Approach 1:
The patent changes the sealing material from glass to plastic, which has thermal expansion characteristics more compatible with metal housings and electronic components. This reduces thermal stress and expansion mismatch issues that cause leaks over time, thereby improving long-term sealing stability and service life.
Solution Approach 2:
The patent employs plastic as a composite sealing material that combines flexibility, thermal compatibility, and sealing effectiveness. The plastic material can accommodate thermal expansion and contraction of the metal housing and electronic components without creating stress concentrations or gaps that would lead to leaks.
4Reliability
If high temperature sealing is used for glass-m metal seals, then hermetic sealing is achieved, but electronic components are damaged due to temperature tolerance limits
Solution Approach 1:
The patent changes the sealing temperature parameter from high temperature (required for glass-m metal bonding) to low temperature (compatible with electronic component tolerances). Plastic sealing materials can be molded and cured at temperatures that do not damage sensitive electronics, eliminating the thermal damage problem while achieving adequate sealing.
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 solution provides reliable and cost-effective protection for pump electronics with reduced thermal load, preventing leaks and ensuring long-term stability while maintaining electronic functionality, and allows for simpler and less expensive production processes.
Implementation Method 1
a small amount of fuel, mainly in the form of fuel vapor, can penetrate into the metal housing
Implementation Method 2
The electrical connections can be sealed off from the openings in the floor in a particularly simple manner if the plastic is introduced by means of injection molding
Data Source
Figure 1~2
Figure 3~4
AI summary
The pump (1) has a housing (21), and a pumping stage (4) arranged in the housing for conveying fuel. An electric motor (6) has a stator (8) and a rotor (7) arranged on a shaft (5) that drives the pumping stage. Pump electronics for controlling the pump are arranged in a metal housing (10) that comprises a base and a cover. The metal housing is arranged in the housing of the pump, where the cover and the base are connected with one another. The base has openings in which electrical connections i.e. pins, are arranged, where the connections are sealed against the openings by using plastic.