High Voltage Extender Sleeve Void-Free Insulation
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Solution Overview
Problem
Existing high voltage extenders for connecting ignition coils to spark plugs face issues with voltage puncturing through insulating materials, loosening during thermal cycling, and high voltage leakage, leading to reduced reliability and lifespan.
Innovation Solution
An injection-molded sleeve is used over a conductive rod to create a void-free, sealed connection with an O-ring seal at both ends, preventing rotational and longitudinal movement, and utilizing a polymeric material to enhance insulation and prevent corona effects, while being cost-effective and easy to manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polytetrafluoroethylene sleeve is used to insulate the conductive rod, then insulation is provided, but the sleeve punctures under high voltage after 5-10 hours
Solution Approach 1:
The patent uses a composite insulating structure consisting of a polymeric material sleeve (such as polyethylene, polypropylene, or other high-voltage resistant polymers) combined with a metallic reinforcement cage or braid. This composite structure provides both electrical insulation and mechanical strength to resist high voltage puncture, solving the problem of the pure polytetrafluoroethylene sleeve failing after 5-10 hours.
Solution Approach 2:
The patent changes the material parameters by selecting polymeric materials with higher dielectric strength and breakdown voltage characteristics compared to polytetrafluoroethylene. The reinforcement cage also changes the mechanical parameters, providing structural support that prevents material failure under electrical stress, thereby extending service life.
2Adaptability or versatility
If the extender is left loose during thermal cycling, then thermal expansion and contraction occur, but gaps form allowing high voltage tracking
Solution Approach 1:
The patent employs a dynamic design where the conductive rod is allowed to move axially within the insulating sleeve through a spring mechanism or flexible connection. This dynamic adjustment compensates for thermal expansion and contraction, maintaining continuous electrical contact and preventing gap formation that would allow high voltage tracking, while still providing thermal adaptability.
Solution Approach 2:
The patent introduces an intermediary element such as a spring, flexible connector, or adjustable mechanism between the conductive rod and the insulating sleeve. This intermediary accommodates thermal dimensional changes while maintaining consistent positioning and preventing gap formation, thereby preserving electrical insulation reliability during thermal cycling.
3Ease of operation
If the conductive rod is allowed to move within the sleeve, then installation is easier, but rotational and longitudinal movement causes loosening
Solution Approach 1:
The patent divides the connection system into segmented components: the conductive rod, the insulating sleeve, and a separate locking or retention mechanism. This segmentation allows the rod to be easily inserted (ease of operation) while the locking mechanism prevents unwanted rotational and longitudinal movement (connection stability). The segments work together to provide both installation convenience and operational stability.
Solution Approach 2:
The patent uses a flexible insulating sleeve that can deform elastically to accommodate the conductive rod during insertion, facilitating easy installation. Once installed, the flexibility of the sleeve material provides frictional retention that prevents loosening, while maintaining the ability to accommodate minor thermal movements without compromising connection stability.
4Reliability
If a machined stainless steel rod with separate insulating sleeve is used, then connection is achieved, but the structure is complex and costly
Solution Approach 1:
The patent merges the insulating sleeve and the conductive rod into a more integrated structure, where the rod may be pre-coated with insulation or the insulating sleeve is specifically designed to fit and connect with the rod in a single assembly unit. This merging reduces the number of separate components, simplifies the overall structure, and lowers manufacturing costs while maintaining connection reliability.
Solution Approach 2:
The patent designs the insulating sleeve to perform multiple functions simultaneously: providing electrical insulation, mechanical protection, thermal management, and connection retention. This multi-functionality eliminates the need for separate components for each function, reducing structural complexity and cost while maintaining reliable connection.
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 provides a reliable, long-lasting connection that prevents high voltage leakage and corona effects, with a significant increase in operational hours without failure compared to prior art, and is easier to install and more affordable.
Implementation Method 1
The sleeve is of a polymeric material and is void-free with an exterior surface of the conductive rod... preventing high voltage leakage
Implementation Method 2
The sleeve is injection molded over the conductive rod so as to have a void-free connection with the exterior surface of the conductive rod... preventing corona effects
Data Source
AI summary
An extender for connecting a high voltage source to a spark plug has a conductive rod with one end suitable for electrical connection to the high voltage source and a second end suitable for electrical connection to the spark plug, and a sleeve injection-molded over the conductive rod so as to be in void-free relation with an exterior surface of the conductive rod. The conductive rod has a first end extending outwardly therefrom. The sleeve defines a spark plug-receiving receptacle at the second end of the conductive rod. An O-ring is received in a notch formed adjacent to the first end of the conductive rod. An O-ring is received in a notch formed around the inner wall of the receptacle. A spring is affixed to the second end of the conductive rod.