Eccentric Component Half-Shell Indexing for Compression Ratio Variation
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Solution Overview
Problem
Existing systems for varying the compression ratio in heat engines face challenges in ensuring precise axial and radial positioning of eccentric parts and resisting load peaks during engine operation, particularly during explosion phases.
Innovation Solution
The proposed solution involves eccentric parts split into half-shells with irregularities on contact faces for improved alignment and resistance, eliminating the need for indexing studs and enhancing load resistance through micro-irregularities or machined shapes, along with a locking mechanism that allows for plastic deformation and easy dismantling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the eccentric part is made as a one-piece structure, then the manufacturing is simpler, but the assembly and disassembly for maintenance becomes difficult
Solution Approach 1:
The eccentric part is divided into two half-shells that can be assembled together to form the complete eccentric structure. This segmentation allows the eccentric part to be disassembled for maintenance while maintaining the structural integrity and functionality when assembled, directly resolving the contradiction between manufacturing simplicity and ease of repair.
2Device complexity
If conventional locking elements are used without irregularities, then the assembly is simpler, but the resistance to load peaks during combustion is insufficient
Solution Approach 1:
Irregularities are introduced at specific locations on the locking elements and corresponding recesses in the half-shells. These localized irregularities create interference fits that significantly enhance the resistance to load peaks during combustion, while the overall locking mechanism remains relatively simple in design and implementation.
3Manufacturing precision
If indexing pins are used for positioning, then the positioning precision is achieved, but the device complexity increases
Solution Approach 1:
The conventional indexing pins are removed from the design. Instead, the positioning function is achieved through the irregularities on the locking elements and corresponding recesses in the half-shells, which provide both positioning and locking functions in a single integrated feature, thereby reducing device complexity while maintaining positioning precision.
Data Source
Figure 1~2
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Figure 5~6a
AI summary
The invention relates mainly to an eccentric component (18) for a system for varying the compression ratio of an internal combustion engine comprising: - a body (19) made from two half-shells (22) assembled with one another, said body (19) comprising a face (23) that is eccentric with respect to an internal face (27) of said body (19), and two annulus gears (24) positioned one on each side of said eccentric face (23), characterized in that said contact faces (50, 51) are centred relative to one another by means of an indexing device (101, 102) and/or of irregularities in relief (52) of complementing shapes formed in said contact faces (50, 51).