Ceramic Pilot Chamber Assembly for Durable Engine Ignition
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Solution Overview
Problem
Existing ignition systems in internal combustion engines face challenges with pilot structure durability due to high thermal loads and material erosion from flame and combustion products, particularly in rotary engines like Wankel engines.
Innovation Solution
The pilot structure is designed as a multicomponent assembly, comprising a ceramic first component and a metal or ceramic second component, with a ceramic forming a majority of the pilot chamber volume, allowing for easier tool access and surface finishing, and is shielded by a cover for protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a monolithic pilot structure is used, then manufacturing is simpler, but tool access and surface finishing become difficult
Solution Approach 1:
The pilot structure is divided into multiple components: a first component with a chamber cavity and a second component with a chamber recess. This segmentation allows tools to access the chamber interior through openings in the first component, enabling proper surface finishing while maintaining manufacturing simplicity through modular assembly.
2Temperature
If ceramic material is used for the pilot structure, then thermal resistance is improved, but material erosion from flame and combustion products increases
Solution Approach 1:
The pilot structure uses a composite design where a ceramic first component provides thermal resistance, and a metal or ceramic second component provides erosion resistance. This composite approach allows each material to contribute its advantageous properties, with the metal second component specifically resisting material erosion from flame and combustion products while the ceramic first component handles thermal loads.
3Temperature
If the pilot structure is shielded by a cover, then protection from thermal loads is improved, but assembly complexity increases
Solution Approach 1:
The pilot structure is segmented into multiple components that can be assembled together, with a cover component providing thermal protection. This segmentation allows the cover to be added as a separate protective element, simplifying the overall assembly process while maintaining effective thermal shielding of the pilot chamber.
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 enhances pilot structure durability by mitigating thermal stresses and material erosion, simplifying assembly and maintenance, and maintaining engine performance.
Implementation Method 1
a ceramic first component (78), a metal or ceramic second component (80)... mitigating thermal stresses
Implementation Method 2
internal combustion engine includes an ignition system for igniting a fuel-air mixture for combustion
Data Source
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AI summary
An assembly for a powerplant includes a housing (34), a primary fuel injector (38) and an ignition system (40). The housing (34) forms a combustion volume (66) within the housing (34). The primary fuel injector (38) is configured to inject primary fuel into the combustion volume (66). The ignition system (40) is configured to ignite the primary fuel within the combustion volume (66). The ignition system (40) includes a pilot fuel injector (70), a pilot ignitor (72), a pilot chamber (74), a first component (78) and a second component (80). The pilot fuel injector (70) is configured to inject pilot fuel into the pilot chamber (74). The pilot ignitor (72) is configured to ignite the pilot fuel within the pilot chamber (74). The pilot chamber (74) is fluidly coupled with the combustion volume (66) through an aperture in the first component (78). The pilot chamber (74) is formed by and disposed between the first component (78) and the second component (80). The first component (78) is configured from or otherwise include a ceramic.