Variable-Heat Spark Plug for Fouling and Pre-Ignition Control
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Solution Overview
Problem
Boosted engines face issues with spark plug fouling at low loads and pre-ignition at high loads, particularly during vehicle marshalling, where the engine operates at varying loads and temperatures.
Innovation Solution
A spark plug design featuring a metallic body, ceramic insulator, and bias device that adjusts the crimp flange to switch between lower and higher heat dispersal states, reducing fouling and pre-ignition by modifying the spark plug gap based on engine load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cold spark plug is used, then spark plug fouling is reduced at low engine loads, but pre-ignition risk increases at high engine loads
Solution Approach 1:
The spark plug incorporates a movable ceramic insulator that can shift position to dynamically change the spark plug gap dimensions. A bias device applies force to position the ceramic insulator, enabling the system to adapt between cold and hot operating characteristics based on engine load conditions, thus resolving the contradiction between fouling resistance and pre-ignition prevention
Solution Approach 2:
The invention changes the physical parameters of the spark plug by adjusting the position of the ceramic insulator, which directly alters the spark plug gap size and heat dispersal characteristics. This parameter adjustment allows the spark plug to transition between cold and hot states, simultaneously addressing both fouling resistance and pre-ignition prevention requirements
2Object-affected harmful factors
If a hot spark plug is used, then pre-ignition is prevented at high engine loads, but spark plug fouling increases at low engine loads
Solution Approach 1:
The movable ceramic insulator with bias device enables dynamic adjustment of spark plug gap dimensions, allowing the system to switch between hot and cold characteristics. This dynamic capability ensures the spark plug can prevent pre-ignition at high loads while avoiding fouling at low loads, resolving the contradiction between these two opposing requirements
Solution Approach 2:
By changing the position of the ceramic insulator, the invention alters the spark plug gap parameters and heat dispersal properties. This parameter change mechanism allows the spark plug to adapt its thermal characteristics, simultaneously achieving pre-ignition prevention and fouling resistance across different operating conditions
3Ease of manufacture
If the spark plug gap is fixed, then manufacturing simplicity is maintained, but adaptability to varying engine load conditions is reduced
Solution Approach 1:
The spark plug is segmented into movable and fixed components, with the ceramic insulator designed to move independently within the metallic body. This segmentation allows the gap dimensions to be adjusted while maintaining relatively simple manufacturing processes for each individual component, thus balancing manufacturing ease with operational adaptability
Solution Approach 2:
The invention introduces dynamic capability to the spark plug gap through the movable ceramic insulator. The bias device provides a simple mechanical solution to enable this movement, maintaining manufacturing simplicity while achieving adaptability to varying engine load conditions through the dynamic adjustment of gap dimensions
Data Source
AI summary
System and methods for operating a vehicle that includes a boosted engine are described. In one example, a spark plug may be adjusted between two operating states to reduce a possibility of pre-ignition and spark plug fouling. A first operating state may be conducive to operating the engine at light loads. The first operating state may be conducive to operating the engine at higher loads.