Ignition Coil Conductive Polymer Assembly
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Solution Overview
Problem
The existing ignition coil assembly process is complex and costly due to the need for soldering high-voltage and low-voltage ends to their respective terminals, which poses challenges in handling high-voltage terminals and adds expense with the inclusion of separate RF suppression resistors.
Innovation Solution
The ignition coil employs a magnetically-permeable core with primary and secondary windings, where at least one end of the secondary winding is directly electrically connected to a terminal using an electrically conductive polymer within a recessed case, eliminating the need for soldering and incorporating RF suppression directly through the polymer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldering is used to connect secondary winding ends to terminals, then reliable electrical connection is achieved, but assembly complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical soldering process with a chemical bonding process using conductive adhesive. The conductive adhesive is applied to the terminal and bonded to the secondary winding end, eliminating the need for soldering equipment and complex assembly steps while maintaining reliable electrical connection.
Solution Approach 2:
The patent changes the connection method from thermal-mechanical (soldering) to chemical-adhesive (conductive adhesive bonding). This parameter change simplifies the assembly process by eliminating melting, cooling, and flux management steps associated with soldering, while the conductive adhesive provides sufficient electrical and mechanical bonding reliability.
2Object-affected harmful factors
If high-voltage terminals are bent and formed to minimize electric field concentrations, then RF interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent introduces an intermediary substance (conductive adhesive) between the terminal and the secondary winding end. This intermediary not only provides electrical connection but also serves as an insulating barrier and stress distributor, reducing the need for complex terminal shaping to control electric field concentrations.
3Object-affected harmful factors
If separate resistors are added for RF suppression, then radio frequency interference is reduced, but component count and cost increase
Solution Approach 1:
The patent merges multiple functions into the conductive adhesive: electrical connection, mechanical bonding, RF suppression, and insulation. By incorporating resistive properties and dielectric characteristics into the adhesive itself, the need for separate resistors and insulators is eliminated, reducing component count while maintaining RF interference suppression.
Solution Approach 2:
The conductive adhesive serves multiple functions simultaneously: it provides electrical conductivity for signal transmission, mechanical adhesion for structural integrity, RF suppression through its resistive properties, and electrical insulation from the case through its dielectric characteristics. This multi-functionality eliminates the need for multiple separate components.
4Reliability
If conventional terminal assembly methods are used, then electrical connection is achieved, but assembly time and labor cost increase
Solution Approach 1:
The patent replaces the multi-step mechanical soldering process with a single-step chemical bonding process using conductive adhesive. This substitution eliminates the need for soldering irons, flux application, heating, cooling, and cleaning steps, significantly improving assembly productivity while maintaining connection reliability.
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 approach simplifies the assembly process, reduces costs by eliminating soldering steps, and provides effective RF interference suppression without additional components, enhancing the overall efficiency and cost-effectiveness of the ignition coil.
Implementation Method 1
at least one of the low-voltage end of the secondary winding and the high-voltage end of the secondary winding is electrically connected directly to a terminal through an electrically conductive polymer
Implementation Method 2
a secondary winding disposed outward of the primary winding and inductively coupled to the primary winding, the secondary winding terminating at one end thereof in a low-voltage end and terminating at another end thereof in a high-voltage end, wherein a high voltage is induced on the secondary winding when an electric current applied to the primary winding is stopped
Data Source
AI summary
An ignition coil includes a magnetically-permeable core; a primary winding disposed outward of the core; a secondary winding disposed outward of the primary winding, inductively coupled to the primary winding, and terminating at one end thereof in a low-voltage end and terminates at another end thereof in a high-voltage which is electrically connected directly to a terminal through an electrically conductive polymer; and a case defining an interior having an interior surface such that the core, the primary winding, and the secondary winding are received within the interior of the case such that the at least one of the low-voltage end and the high-voltage end, the terminal, and the electrically conductive polymer are disposed within the recess and such that the electrically conductive polymer is in direct contact with the interior surface within the recess.