Breather Chamber Design for Compact Engine Volume
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Solution Overview
Problem
Conventional internal combustion engine designs with a breather chamber outside the cam chain locus result in increased engine size due to the bulging of the breather chamber, which is not ideal for space-constrained applications.
Innovation Solution
A breather chamber design that utilizes the space formed by the rotation locus of the cam chain, with a rib sloping downward from the cam chain chamber cover to facilitate oil discharge and a partitioning member formed of a flat plate to divide the breather chamber from the cam chain chamber, allowing for a larger breather chamber volume without increasing the engine size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the breather chamber is provided outside the rotation locus of the cam chain, then the breather chamber can be formed with sufficient volume, but the cam chain chamber bulges outward causing an increase in engine size
Solution Approach 1:
The breather chamber is repositioned from a conventional external location to an internal location within the cam chain chamber, specifically on the side of the plane formed by the cam chain rotation locus. This spatial reconfiguration allows the breather chamber to utilize previously unused internal space, achieving sufficient volume without external bulging that would increase engine size.
2Volume of moving object
If the breather chamber is positioned to maximize volume, then oil discharge becomes difficult, but compact positioning limits breather chamber size
Solution Approach 1:
The cam chain chamber is divided into two functional regions by a partitioning member: a cam chain housing region and a breather chamber region. This segmentation allows the breather chamber to be positioned internally with optimized volume while maintaining distinct functional zones that facilitate proper oil discharge pathways and prevent oil scattering into the breather chamber.
Solution Approach 2:
A partitioning member is introduced as an intermediary structure between the cam chain chamber and breather chamber. This partitioning member not only separates the two functional regions but also provides a structured interface that guides oil flow and prevents oil from entering the breather chamber, thereby maintaining both compact size and effective oil discharge.
3Length of stationary object
If a partitioning member is used to divide the breather chamber, then the breather chamber can be formed internally without increasing engine size, but the device complexity increases
Solution Approach 1:
The partitioning member serves multiple functions simultaneously: it divides the cam chain chamber into distinct regions for the cam chain and breather chamber, provides structural support for maintaining chamber integrity, facilitates oil flow management, and prevents oil scattering into the breather chamber. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 enables a larger breather chamber volume while maintaining a compact engine size, facilitating easy oil discharge and installation, especially in vehicles with longitudinal space limitations.
Implementation Method 1
a rib protruding from the cam chain chamber cover into the breather chamber is formed to slope downward along an inner surface of the cam chain chamber cover between the inlet and the outlet, the rib being formed to be inclined downward from an end connected to an inner circumferential wall surrounding the crankshaft to an open end in the breather chamber
Data Source
Figure 1
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AI summary
A breather chamber 7 of an internal combustion engine 4 includes looped cam chains 65L and 65R for transmitting power from a horizontally disposed crankshaft 31 to camshafts 61 L and 61 R provided in cylinder heads 43L and 43R, and includes cam chain chambers 63L and 63R disposed along side portions 46La and 46Ra of cylinder block portions 46L and 46R which intersect the direction of the crankshaft 31. The breather chamber 7 is located on a side of a plane P formed by a rotation locus L of the cam chain 65R in the direction of the crankshaft 31 in the cam chain chamber 63R. Thus, a breather chamber having a large size can be formed while an increase in the size of the internal combustion engine is suppressed.