Piston Arrangement with Rotatable Track for Wear Reduction
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Solution Overview
Problem
Existing power transfer mechanisms in engines, such as those described in WO 2015/107330 A2, FR2655378 A1, and US1374164 A, subject the cam surface and follower to high loads, leading to wear and inefficiencies.
Innovation Solution
A piston arrangement with a rotatable element and track system, featuring engagement profiles and followers, reduces wear by distributing forces and optimizing power transfer through non-sinusoidal piston movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a cam surface and follower are used to transfer power from the piston, then power transfer is achieved, but the cam surface and follower are subjected to high loads leading to wear
Solution Approach 1:
The power transfer function is segmented between two separate engagement mechanisms: the first engagement profile (rigidly coupled to the piston) transfers power during the power stroke, while the second engagement profile (on the rotatable element) transfers power during the return stroke. This segmentation distributes the mechanical loads across different components and time periods, reducing wear on any single component while maintaining continuous power transfer capability.
2Power
If the piston is directly coupled to the track by a follower, then power transfer is achieved, but wear on the track increases
Solution Approach 1:
The rotatable element acts as an intermediary mechanism between the piston-coupled track and the output shaft. The engagement profiles on the rotatable element provide a controlled interface for power transfer, distributing forces more evenly and reducing direct wear on the track surface while maintaining effective power transmission to the output shaft.
Data Source
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AI summary
A piston arrangement includes a piston movable within a cylinder in reciprocating motion along a piston axis, a rack movable with the piston, a sector gear configured to engage and disengage the rack and rotatable around a sector gear axis, a track adapted to rotate relative to the cylinder around a track axis of rotation, the piston being coupled to the track. The sector gear and the track are coupled in rotation. The track may have a shape such that the movement of the piston coupled to the track is substantially non simple harmonic. Also, an internal combustion engine comprising the piston arrangement.