Camshaft Storage Space Separation in Internal Combustion Engine
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Solution Overview
Problem
Internal combustion engines with dual lubricating oil circulation passages face challenges in reducing the axial dimension of the cylinder head and the entire engine, as the existing designs struggle to prevent communication between the camshaft and chain storage spaces, leading to increased dimensions and potential lubricating oil mixing.
Innovation Solution
The design incorporates a camshaft with rotatably supported portions and cam caps that create a non-communicating interlocking member storage space with the camshaft storage space, using a semi-solidified gasket in cross-sectional area gradually changing gaps to maintain separation and prevent lubricating oil leakage, thereby reducing engine dimensions and maintaining oil purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the camshaft storage space and chain storage space are separated to prevent lubricating oil mixing, then the purity of the second lubricating oil is maintained, but the axial dimension of the engine increases
Solution Approach 1:
The camshaft storage space is nested within the cylinder head structure, with the camshaft positioned in a recess that is integrated into the cylinder head's axial profile. The chain cover adjacent wall forms part of the cylinder head and creates a through-hole that allows the camshaft to pass through, effectively nesting the camshaft storage function within the existing cylinder head volume without increasing axial dimension.
Solution Approach 2:
The separation between camshaft storage space and chain storage space is achieved not by axial displacement but by radial partitioning. The chain cover adjacent wall acts as a partition that divides the internal volume of the cylinder head into separate zones for camshaft storage and chain storage, maintaining compact axial dimensions while ensuring oil purity through spatial separation.
2Reliability
If a partition wall is used to separate the camshaft storage space from the chain storage space, then lubricating oil mixing is prevented, but the device complexity increases
Solution Approach 1:
The chain cover adjacent wall serves multiple functions simultaneously: it forms part of the outer peripheral wall of the cylinder head, provides structural support, creates the through-hole for camshaft passage, and acts as the partition wall separating the camshaft storage space from the chain storage space. This multi-functionality reduces the need for additional dedicated partition components, thereby reducing device complexity.
Solution Approach 2:
The partition wall function is merged with the chain cover adjacent wall structure rather than being implemented as a separate component. The same structural element that provides mechanical support and defines the cylinder head boundary also serves as the separation barrier between the two lubricating oil circulation passages, simplifying the overall device structure.
3Length of moving object
If the camshaft is positioned closer to reduce engine dimensions, then the axial dimension is reduced, but the risk of lubricating oil communication between spaces increases
Solution Approach 1:
The chain cover adjacent wall provides localized separation quality at the critical interface between the camshaft storage space and chain storage space. The through-hole in this wall is specifically designed with oil seal engagement to maintain local separation integrity, ensuring that even when the camshaft is positioned close to other components, the lubricating oil circulation passages remain separated through the localized sealing quality at the partition wall.
Data Source
AI summary
Side surfaces of an end cam cap and a pair of side surfaces of a recess for cam cap form two cross-sectional area gradually changing gaps therebetween. A gasket is filled between an inner surface of the recess for cam cap and an outer surface of the end cam cap. The inner surface includes the side surfaces of the recess for cam cap and the outer surface includes the side surfaces of the end cam cap.