Fuel Pump Assembly with Grounded Plastic Components
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Solution Overview
Problem
The unpredictability of conductive paths and electromagnetic interference (EMI) protection in molded conductive plastic materials used in in-tank fuel pumps leads to inconsistent performance in electrostatic charge dissipation and shielding.
Innovation Solution
A non-conductive plastic reservoir and fuel pump assembly with a conductive material coating applied through a dipping process to ensure a uniform and reliable conductive path for electrostatic discharge and EMI protection, including a fuel filter assembly and support members, providing a continuous conductive layer for effective grounding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive material is mixed with plastic and molded into a single component, then manufacturing is simplified and integrated, but the conductive path becomes unpredictable and non-uniform
Solution Approach 1:
The fuel pump assembly is divided into separate non-conductive plastic components (reservoir, cover, support members) that are assembled together, with conductive material applied as a coating on each component's exterior surfaces. This segmentation allows each component to be manufactured independently from standard plastic materials, while the conductive coating is applied uniformly through a dipping process, resolving the contradiction between manufacturing integration and conductive path uniformity.
Solution Approach 2:
The solution uses a composite structure where non-conductive plastic materials are combined with conductive material coatings. The plastic provides structural integrity and non-conductive properties, while the conductive coating provides uniform electrostatic discharge paths and EMI shielding. This composite approach allows standard plastic materials to be used while achieving reliable conductive performance.
2Object-affected harmful factors
If conductive material is molded into plastic components, then EMI shielding is provided, but the conductive path becomes unpredictable due to variations in conductive material content and disbursement
Solution Approach 1:
The conductive material coating is applied to the exterior surfaces of the plastic components before assembly. This preliminary action ensures that the conductive material is uniformly distributed on the surfaces that will be exposed to the fuel tank environment, creating reliable conductive paths for EMI shielding and electrostatic discharge before the components are assembled into the final product.
Solution Approach 2:
The conductive material is applied as a coating layer rather than being mixed into the plastic matrix. This parameter change from internal mixing to external coating allows for controlled, uniform application of conductive material on surfaces, ensuring consistent conductive properties and reliable EMI shielding performance.
3Ease of manufacture
If standard non-conductive plastic materials are used, then manufacturing cost is reduced, but electrostatic discharge and EMI protection are compromised
Solution Approach 1:
The conductive material coating acts as an intermediary layer between the non-conductive plastic components and the required conductive performance. This coating mediates between the use of inexpensive standard plastic materials and the need for reliable electrostatic discharge and EMI shielding, allowing both cost-effectiveness and protective functionality to coexist.
Solution Approach 2:
The conductive material is applied as a thin film coating on the exterior surfaces of the plastic components. This thin film approach provides sufficient conductive protection for electrostatic discharge and EMI shielding while using minimal conductive material, maintaining cost-effectiveness while achieving the required protective functionality.
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
The solution ensures a uniform and reliable conductive path for static electricity discharge and complete EMI shielding, while allowing the use of economical standard plastic materials, ensuring consistent performance and manufacturing efficiency.
Implementation Method 1
The conductive material within the molded component provides a conductive path through which electrostatic charges can be dissipated
Implementation Method 2
providing shielding against electromagnetic interference (EMI)
Implementation Method 3
A coating of conductive material is bonded to the housing
Data Source
AI summary
A vehicle fuel pump assembly, method of construction thereof, and a fuel tank assembly is provided. The fuel pump assembly includes a non-conductive plastic reservoir and an electrically powered fuel pump disposed in the reservoir. The fuel pump is configured to receive fuel through an inlet and to dispense fuel through an outlet. A fuel filter assembly having a non-conductive plastic housing is disposed in the reservoir and a coating of conductive material is bonded to the housing. A conductive lead is configured in electrical communication with the coating and is further configured for attachment to an electrical ground.