Single Cylinder Engine Breather Chamber Design
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Solution Overview
Problem
Single cylinder internal combustion engines face challenges in improving gas/liquid separation performance while maintaining compactization due to the small size of the cylinder head and head cover, which limits the effectiveness of breather chamber designs.
Innovation Solution
A single cylinder internal combustion engine design featuring a long hole portion in the plug hole between the cylinder head and head cover, with the breather chamber surrounding this long hole, and strategically placed cam holder attaching bolts within the long hole portion, along with a partition wall to separate the cam chain chamber and inlet, enhancing gas circulation and preventing oil mist intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the breather chamber is designed with a long gas circulation route to improve gas/liquid separation performance, then the gas/liquid separation performance is improved, but the engine compactization is compromised due to increased space requirements
Solution Approach 1:
The breather chamber is nested within the existing cylinder head and head cover structure, utilizing the long hole portion of the plug hole as a core component. The chamber is formed by strategically positioning cam holder attaching bolts within the long hole portion, allowing the breather chamber to be integrated into the existing engine architecture without requiring additional external space, thus maintaining compactization while achieving improved gas/liquid separation performance
Solution Approach 2:
The breather chamber utilizes the longitudinal dimension of the engine by extending the gas circulation route through the long hole portion of the plug hole, which stretches in the cylinder arraying direction. This dimensional approach allows the chamber to achieve adequate gas circulation path length within the constrained transverse dimensions of a single-cylinder engine, improving separation performance without proportionally increasing overall engine volume
2Reliability
If the plug hole is modified to include a long hole portion to accommodate breather chamber and cam holder attaching bolts, then the gas circulation route is extended, but the structural complexity of the plug hole increases
Solution Approach 1:
The long hole portion of the plug hole serves multiple functions simultaneously: it acts as a structural reinforcement element for the plug hole, provides a mounting location for cam holder attaching bolts, and forms the core structure of the breather chamber to enable extended gas circulation. This multi-functionality reduces the need for separate structural components, thereby limiting the increase in overall structural complexity despite the modified plug hole geometry
Data Source
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AI summary
In a single cylinder internal combustion engine in which a plug hole (96) is provided striding between a cylinder head (30) and a head cover (31), and an intake side camshaft (57) and an exhaust side camshaft (58) are disposed at positions sandwiching the plug hole (96) therebetween, a long hole portion formed long in a direction orthogonal to axes of the camshafts (57, 58) is formed as a part of the plug hole (96). A part of a plurality of cam holder (61) attaching bolts (66-69) used for fastening the cam holder (61) to the cylinder head (30) are disposed within the long hole portion. A breather chamber (106) disposed around the long hole portion is formed between the head cover (31) and a breather plate (105) attached thereto.