Sub-chamber Communication Holes for Residual Gas Purging
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Solution Overview
Problem
In internal combustion engines with a sub-chamber for spark ignition, residual gases from previous cycles often lead to deteriorated ignitability and combustibility due to inadequate purging in the sub-chamber.
Innovation Solution
The engine design includes strategically positioned and inclined communication holes between the sub-chamber and the main combustion chamber, with the first hole closer to the piston and inclined towards the piston, and the second hole closer to the cylinder head, both narrowing in specific directions to enhance intake and discharge of purge flows, and a third hole in the sub-chamber's bottom wall to promote negative pressure for effective purging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sub-chamber is provided in the main combustion chamber for spark ignition, then combustion efficiency is improved, but residual gases accumulate in the sub-chamber causing deteriorated ignitability and combustibility
Solution Approach 1:
The combustion chamber is segmented into a main combustion chamber and a sub-chamber, with the sub-chamber serving as a dedicated ignition zone. This segmentation allows for focused combustion initiation while managing residual gas effects within the confined sub-chamber space through strategically positioned communication holes.
Solution Approach 2:
Communication holes are provided in the sub-chamber to extract residual gases from the sub-chamber into the main combustion chamber. This extraction mechanism prevents residual gas accumulation that would otherwise deteriorate ignitability and combustibility in the sub-chamber.
2Reliability
If communication holes are provided in the sub-chamber for purging residual gases, then ignitability is improved, but the structural complexity of the sub-chamber increases
Solution Approach 1:
The communication holes are strategically positioned at specific locations on the sub-chamber (intake side and exhaust side) rather than uniformly distributed. This local quality approach provides effective purging functionality while minimizing the number of holes needed, thus reducing structural complexity.
Solution Approach 2:
The communication holes serve multiple functions: they enable purging of residual gases during the intake stroke, facilitate flame propagation from the sub-chamber to the main combustion chamber, and contribute to tumble flow generation. This multi-functionality reduces the need for additional separate structures.
3Productivity
If the first communication hole is positioned closer to the piston and inclined towards the piston, then intake flow entry into the sub-chamber is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The first communication hole is positioned asymmetrically closer to the piston side and is inclined towards the piston, while the second communication hole is positioned closer to the exhaust opening portion. This asymmetric arrangement optimizes the intake flow entry into the sub-chamber by aligning the hole inclination with the flow direction, enhancing purge efficiency.
Solution Approach 2:
The communication holes are designed with predetermined inclination angles and positions that pre-align with the expected intake flow direction. This preliminary action ensures that the flow enters the sub-chamber efficiently without requiring complex real-time adjustments or higher manufacturing tolerances during operation.
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 configuration improves purging efficiency in the sub-chamber, reducing residual gases and enhancing ignitability and combustibility, while also strengthening the tumble flow in the main combustion chamber during combustion.
Implementation Method 1
The first communication hole is inclined so as to be closer to the piston as the first communication hole is positioned toward the inside from the outside of the sub-chamber
Implementation Method 2
a sufficient amount of intake flow is introduced into the sub-chamber through the first communication hole
Implementation Method 3
the first communication hole may narrow toward the inside from the outside of the sub-chamber
Implementation Method 4
a spark plug provided so as to perform ignition in the sub-chamber
Implementation Method 5
combustion is started by performing spark ignition in the sub-chamber
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An internal combustion engine includes: a main combustion chamber (10); an intake port (30) connected to the main combustion chamber; an exhaust port (40) connected to the main combustion chamber; a sub-chamber (50); and a spark plug (60) in the sub-chamber. The sub-chamber is provided between the intake opening portion and the exhaust opening portion and connected to the main combustion chamber through a plurality of communication holes. The communication holes include a first communication hole (51i) provided on the intake opening portion side, and a second communication hole (51e) provided on the exhaust opening portion side. The first communication hole (51i) is closer to the piston than the second communication hole (51e) is. The first communication hole (51i) is inclined to be closer to the piston as the first communication hole (51i) is positioned toward the inside from the outside of the sub-chamber (50).