Cam Pulley Seal Layout for Compact Internal Combustion Engines
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Solution Overview
Problem
The existing internal combustion engines with timing belts suffer from lubricating oil adhesion, leading to deterioration and size constraints due to suboptimal sealing between the cylinder head and camshaft support member, which limits the reduction of lubricating oil leakage and engine size.
Innovation Solution
An internal combustion engine design featuring a seal member that provides axial-direction sealing between the cylinder head and support structure, increasing the seal surface area and reducing lubricating oil leakage, while allowing for a smaller overall engine size by recessing the cam pulley within the support structure, thereby minimizing interference with the cam pulley.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sealing between the cylinder head and camshaft support member is provided in the height direction, then leakage of lubricating oil is reduced, but the overall engine size cannot be reduced due to the cam pulley occupying space
Solution Approach 1:
The seal member extends in the axial direction of the camshaft rather than only in the height direction, utilizing a different spatial dimension to achieve sealing. This allows the seal surface to be positioned outside the cam pulley's radial range, enabling both effective sealing and compact engine size by recessing the cam pulley within the support structure.
2Volume of moving object
If the cam pulley is positioned closer to the cylinder head to reduce engine size, then the overall dimensions are reduced, but sealing performance deteriorates due to limited seal surface area
Solution Approach 1:
The seal member is configured to extend in the axial direction of the camshaft, creating a seal surface that is positioned radially outside the cam pulley's range. This dimensional arrangement allows the seal surface area to be increased without increasing the radial dimensions of the engine, thus maintaining compact size while improving sealing performance.
3Reliability
If the seal surface area is increased to improve sealing performance, then lubricating oil leakage is reduced, but the engine size increases due to the cam pulley occupying space
Solution Approach 1:
The seal member extends axially along the camshaft, positioning the seal surface in a location that does not conflict with the cam pulley's radial space. This allows the seal surface area to be maximized in the axial direction while the cam pulley is recessed within the support structure, achieving both improved sealing and compact engine dimensions.
Solution Approach 2:
The cam pulley is recessed within the support structure, nesting it inside the available space. This nesting arrangement allows the seal member to extend around the cam pulley in the axial direction, creating a large seal surface area without increasing the overall engine envelope dimensions.
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 ensures effective sealing performance, reducing lubricating oil leakage and enabling a more compact engine size, even with Variable Valve Timing (VVT) applications.
Implementation Method 1
A seal member is provided to cover a gap provided between the cylinder head and the support structure at a facing surface facing the cam pulley. The seal member provides sealing between the cylinder head and the support structure in the axial direction of the camshaft.
Data Source
AI summary
An internal combustion engine includes a cylinder head, a support structure, a cam pulley, and a seal member. The support structure is provided above the cylinder head and supports the camshaft. The cam pulley is provided at an end of the camshaft. A timing belt is wound around the cam pulley. A seal member is provided to cover a gap provided between the cylinder head and the support structure at a facing surface facing the cam pulley. The seal member provides sealing between the cylinder head and the support structure in an axial direction of the camshaft.