Open-Faced Piston Groove Openings for Crevice Combustion
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Solution Overview
Problem
Conventional combustion engines experience unburned hydrocarbon emissions due to the high surface area to volume ratio in crevice volumes between the piston and cylinder, leading to incomplete combustion and reduced efficiency.
Innovation Solution
The piston assembly features a circumferential groove with strategically sized and arranged openings that allow a combustion reaction to propagate into the volume between the piston ring and the cylinder, ensuring a quench distance is exceeded, thereby allowing complete combustion of the fuel and air mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crevice volume between piston and cylinder is maintained for sealing, then sealing effectiveness is improved, but hydrocarbon emissions increase due to incomplete combustion
Solution Approach 1:
The circumferential groove is segmented into multiple sections with openings distributed around the groove. This segmentation allows the combustion reaction to propagate into the crevice volume through multiple access points, ensuring complete combustion while maintaining the sealing function of the piston ring assembly.
Solution Approach 2:
The openings in the circumferential groove act as intermediaries that connect the combustion chamber to the crevice volume. These openings allow the combustion reaction to reach the fuel-air mixture in the crevice volume, enabling complete combustion without compromising the sealing effectiveness of the piston ring assembly.
2Object-generated harmful factors
If openings are added to allow combustion propagation, then hydrocarbon emissions are reduced, but device complexity increases
Solution Approach 1:
The circumferential groove serves multiple functions: it houses the piston ring assembly for sealing, provides structural support, and contains openings that enable combustion propagation. By integrating these functions into a single component, the design reduces overall device complexity while achieving the goal of reducing hydrocarbon emissions.
Solution Approach 2:
The openings are strategically positioned at specific locations around the circumferential groove where they can effectively facilitate combustion propagation. This localized approach ensures that combustion can reach the crevice volume without requiring openings throughout the entire piston structure, thereby minimizing added complexity.
3Object-generated harmful factors
If the distance between piston outer surface and piston ring inner surface is increased to reduce emissions, then combustion completeness is improved, but mechanical strength decreases
Solution Approach 1:
The circumferential groove is divided into multiple sections with openings distributed around it. This segmentation allows combustion to propagate through multiple pathways into the crevice volume, ensuring complete combustion even with a larger distance between the piston surface and ring inner surface, while the segmented structure maintains structural integrity.
Solution Approach 2:
Instead of increasing the radial distance uniformly, the design uses openings in the circumferential groove to create additional pathways for combustion propagation. This dimensional approach allows combustion to reach the crevice volume through the groove openings rather than relying solely on increasing the radial gap, thereby maintaining structural strength.
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 significantly reduces hydrocarbon emissions and improves engine efficiency by ensuring that a majority of the fuel and air mixture is burned within the crevice volumes, enhancing combustion completeness.
Implementation Method 1
the plurality of openings is configured to allow a combustion reaction to propagate into a volume defined between an inner surface of the piston ring assembly and the piston
Implementation Method 2
each of the plurality of openings is sized and arranged such that a minimum opening along a gas path between each opening and the inner surface of the piston ring assembly is at least a quench distance of an oxidizer and fuel mixture in the volume
Data Source
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AI summary
The present disclosure provides an open-faced piston with a circumferential groove into which a piston ring assembly is arranged. Openings at the bottom of the circumferential groove and between a front land of the open-faced piston and the piston face are provided. The openings are arranged to allow for a combustion reaction to propagate through the volume defined between the bottom of the piston ring assembly and the piston face such that at least a portion of an air and fuel mixture located in that volume is reacted.