Corona Ignition Device Compression Spring Shield
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Solution Overview
Problem
Corona ignition devices in internal combustion engines face mechanical stresses from shocks and vibrations, which existing designs struggle to withstand effectively due to manufacturing tolerances and lack of efficient shielding against electromagnetic interference.
Innovation Solution
A mechanically robust corona ignition device is designed with a compression spring between the coil and cover to compensate for manufacturing tolerances, and a metal plate with spring lugs that also serves as an electromagnetic shield, made from conductive materials like copper or aluminum to reduce eddy current losses and provide axial shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid fixed structure is used to hold the coil in the housing, then manufacturing precision is improved, but mechanical robustness against shocks and vibrations deteriorates
Solution Approach 1:
The patent changes the mechanical parameter of the mounting structure from rigid to elastic by introducing a compression spring. This spring allows the coil to be held with sufficient contact force while accommodating position variations due to manufacturing tolerances and external mechanical stresses, thus resolving the contradiction between positioning precision and mechanical robustness.
Solution Approach 2:
The patent introduces a dynamic element (compression spring) that can adapt its compression state based on external forces. The spring allows the coil to move slightly under shock or vibration loads and then return to its positioned state, providing both stability and resilience against mechanical stresses.
2Object-affected harmful factors
If a complete electromagnetic shield is used around the coil, then shielding effectiveness is improved, but device complexity and manufacturing cost deteriorate
Solution Approach 1:
The patent merges two separate functions into a single component: the compression spring also serves as the electromagnetic shield. By coating the spring with conductive material, it simultaneously provides mechanical compensation and electromagnetic shielding, eliminating the need for a separate shield structure and reducing overall device complexity.
Solution Approach 2:
The compression spring is designed to perform multiple functions: mechanical compensation for position variations, providing contact force to hold the coil, and electromagnetic shielding through conductive coating. This multi-functionality reduces the number of components and simplifies the overall device structure.
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 enhances the device's mechanical robustness and reduces electromagnetic interference, allowing it to better withstand mechanical stresses and operate efficiently while being cost-efficiently manufactured.
Implementation Method 1
a spring is arranged between coil and cover. This spring is a compression spring which presses the coil towards the central electrode
Implementation Method 2
the metal plate can complete a shielding of the coil in the axial direction... for this, it is advantageous if the metal plate has a high electrical conductivity
Data Source
AI summary
A corona ignition device is described, with a central electrode, an insulator, in which the central electrode sits, a coil, which is connected to the central electrode, a metal housing, which holds the insulator and surrounds the coil, and a cover, which closes the metal housing at its end facing away from the insulator. According to this disclosure, provision is made for a spring arranged between the cover and the coil. In another aspect, a shield is provided that surrounds the housing and comprises several shell elements which each surround a section of the circumference of the coil.