Four-Wire Elastomeric Seal for Fuel Injector
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Solution Overview
Problem
The integration of electrical actuators in fuel injectors poses new challenges for sealing against fuel leakage, particularly due to the need to bring electrical power without compromising the sealing strategy, and existing sealing solutions are prone to damage during assembly.
Innovation Solution
A four-wire elastomeric sealing member with external annular sealing ridges and internal conductor passages is used to seal against fuel leakage, featuring a unitary elastomeric body with a cylindrical outer surface and elongate guide segment to facilitate assembly and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing strategies like o-rings are used in fuel injectors with electrical actuators, then the sealing against fuel leakage is compromised, but the device complexity remains low
Solution Approach 1:
The sealing member is divided into multiple functional segments: external annular sealing ridges for sealing against the injector body, internal sealing segments for gripping electrical conductors, and an elongate guide segment for assembly guidance. This segmentation allows each portion to perform its specific sealing function effectively while maintaining overall reliability
Solution Approach 2:
The sealing member features nested structures where internal sealing segments are positioned within conductor passages that extend through the elastomeric body. The internal sealing segments are nested within the larger external sealing ridges, creating a multi-layered sealing system that addresses multiple leakage pathways simultaneously
2Reliability
If existing sealing methods are used during assembly, then the sealing strategy may be undermined by damage to sealing members, but the ease of manufacture remains high
Solution Approach 1:
The elongate guide segment is positioned between the annular sealing ridges and internal sealing segments during manufacturing, creating a protective and guiding structure before assembly begins. This preliminary configuration ensures that during assembly, the guide segment leads the sealing member into proper alignment and protects vulnerable sealing surfaces from damage
Solution Approach 2:
The elongate guide segment acts as an intermediary element between the external sealing ridges and internal sealing segments during assembly. It mediates the assembly process by providing a protective interface that prevents direct contact between opposing sealing surfaces, thereby preventing tearing and scratching while maintaining ease of assembly
3Reliability
If electrical conductors are brought to actuators without adequate sealing, then fuel leakage pathways are created, but the ease of operation improves
Solution Approach 1:
The sealing member provides localized sealing quality at different positions: external annular sealing ridges at the outer surface for sealing against the injector body, and internal sealing segments within conductor passages for gripping individual electrical conductors. This localized approach ensures fuel migration is prevented at each specific interface where leakage could occur
Solution Approach 2:
The sealing member features asymmetric geometry with external ridges positioned at the outer circumference and internal sealing segments positioned within internal passages. This asymmetric arrangement optimizes sealing at each interface - external ridges seal against the cylindrical bore while internal segments conform to and grip the round electrical conductors, maintaining reliability while facilitating proper installation
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 effectively seals against fuel leakage along electrical conductors and prevents damage during assembly, ensuring reliable operation over millions of injection cycles by utilizing annular ridges and internal sealing segments to grip conductors and maintain a secure seal.
Implementation Method 1
An elastomeric sealing member has a plurality of external annular sealing ridges in sealing contact with the injector body
Implementation Method 2
each of the four conductor passages includes an internal sealing segment
Data Source
AI summary
A fuel injector includes first and second electrical actuators positioned within an injector body. First and second pairs of electrical conductors extend from a socket connector outside of the injector body to the first and second electrical actuators, respectively. The electrical conductors extend through an elastomeric sealing member that seals against fuel leakage from the fuel injector. The elastomeric sealing member provides annular sealing ridges in sealing contact with an access passage of the injector body and includes individual conductor seal passages that form seals around the outer surface of the individual electrical conductors. The elastomeric sealing member includes features that facilitate assembly of the fuel injector in a manner that reduces risk of damage to the sealing strategy.