Corona Igniter Lip Design for Arcing Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing corona discharge igniters for internal combustion engines experience undesirable arcing and irregular corona emissions in the rollover region due to sharp edges, leading to degraded ignition quality and inefficiency.
Innovation Solution
The design incorporates a corona reducing lip at the upper shell end without sharp edges, ensuring the lip is free of sharp edges and features spherical radii, which reduces arcing and concentrates electrical field emissions at the electrode firing end, enhancing the consistency and strength of the electrical field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shell with a lip is disposed in the rollover region, then the igniter structure is complete and functional, but sharp edges on the lip cause arcing and irregular corona emissions that degrade ignition quality
Solution Approach 1:
The patent applies spheroidality by replacing sharp edges with rounded surfaces. Specifically, the lip at the upper shell end is formed with a spherical radius of curvature (e.g., 0.002 to 0.006 inches) instead of sharp edges. This curvature prevents the concentration of electrical field emissions at edge points, thereby eliminating arcing and irregular corona while maintaining the structural integrity and sealing function of the lip in the rollover region.
2Productivity
If electrical field emissions occur in the rollover region, then the igniter operates, but arcing in this region degrades ignition quality and reduces efficiency
Solution Approach 1:
The spherical radius on the lip prevents electrical field emission in the rollover region by eliminating sharp edges that would concentrate the electrical field. This redirects all electrical field emissions to occur only at the electrode firing end, improving ignition efficiency and preventing energy loss through arcing in the rollover region.
3Use of energy by moving object
If sharp edges are present on the lip, then manufacturing is simpler, but arcing occurs which requires higher voltage to achieve proper ignition
Solution Approach 1:
The spherical radius on the lip eliminates arcing by preventing electrical field emission at the rollover region. This allows the igniter to operate efficiently at lower voltages (e.g., 30 volts) compared to sharp-edged designs that would require higher voltages (e.g., 50 volts) to overcome arcing losses and achieve proper ignition.
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 design results in a more efficient igniter with reduced arcing, improved ignition quality, and significant energy cost savings by emitting a stronger electrical field at lower voltages compared to prior art igniters, providing stable performance over time.
Implementation Method 1
An igniter of a corona discharge ignition system receives a voltage from a power source and emits an electrical field that forms a corona to ionize a mixture of fuel and air
Implementation Method 2
The electrical field includes at least one streamer, and typically a plurality of streamers forming the corona. The corona igniter does not include any grounded electrode element in close proximity to the electrode firing end.
Data Source
AI summary
A corona igniter (20) includes a metal shell (32) with a corona reducing lip (38) spaced from an insulator (26) and being free of sharp edges (40) to prevent arcing (42) in a rollover region and concentrate the electrical field at an electrode firing end (48). The corona reducing lip (38) includes lip outer surfaces (88) being round, convex, concave, or curving continuously with smooth transitions (90) therebetween. The corona reducing lip (38) includes lip outer surfaces (88) presenting spherical lip radii (r1) being at least 0.004 inches. The corona igniter (20) also includes shell inner surfaces (104) and insulator outer surfaces (75) facing one another being free of sharp edges (40).