Variable Compression Ratio Engine Using Connecting Rod Eccentric
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Solution Overview
Problem
Existing engines with variable compression ratios require additional links and joints, increasing manufacturing complexity, inertia, and friction, which limits efficiency gains and requires extensive balancing, making them bulky and costly.
Innovation Solution
A compact engine design with a connecting rod eccentric and eccentric lever system that adjusts the compression ratio by offsetting the crankpin and using a minimal number of links, allowing for controlled variation of the Top Dead Center position of the piston with a compression ratio adjustment mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional links and joints are added to the linkage between the crankshaft and the piston to achieve variable compression ratio, then the compression ratio can be varied, but the manufacturing complexity increases, the number of potential failure points increases, and the overall friction increases
Solution Approach 1:
The patent merges the connecting rod and eccentric lever into a single integrated component called a connecting rod eccentric. This consolidation eliminates the need for separate links and joints between the crankshaft and piston, achieving variable compression ratio capability while reducing linkage complexity and the number of potential failure points
Solution Approach 2:
The connecting rod eccentric serves multiple functions simultaneously: it acts as both the connecting rod and the eccentric lever, provides the crankpin engagement, and enables compression ratio variation. This multi-functionality reduces the overall number of components needed in the linkage system
2Adaptability or versatility
If additional links and joints are added to the linkage between the crankshaft and the piston to achieve variable compression ratio, then the compression ratio can be varied, but the inertia of the reciprocating and/or rotating mass increases, requiring extensive balancing
Solution Approach 1:
By combining the connecting rod and eccentric lever into a single connecting rod eccentric component, the patent reduces the total reciprocating mass. Fewer separate links and joints mean less total mass that requires balancing, thereby reducing inertial forces while maintaining variable compression ratio capability
3Adaptability or versatility
If additional links and joints are added to the linkage between the crankshaft and the piston to achieve variable compression ratio, then the compression ratio can be varied, but the engine becomes bulky
Solution Approach 1:
The integration of the connecting rod and eccentric lever into a single compact connecting rod eccentric component reduces the spatial requirements of the linkage system. This consolidation eliminates the need for multiple separate links and joints, resulting in a more compact engine design with reduced overall volume
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 achieves increased fuel efficiency and reduced emissions by minimizing additional links and joints, lowering inertial forces, and simplifying balancing, resulting in a more compact and efficient engine.
Implementation Method 1
A connecting rod eccentric has an eccentric internal bore engaged with the at least one crankpin. The connecting rod eccentric also has an eccentric external cylindrical surface. The eccentric external cylindrical surface has a centerline that is offset from the centerline of the eccentric internal bore.
Data Source
AI summary
A compression ratio varying arrangement of an engine is adapted to work with a crankshaft having at least one crankpin offset from the centerline of the crankshaft. An eccentric has an internal bore engaged with the crankpin, and an external cylindrical surface that has a centerline that is offset from the centerline of the internal bore. A connecting rod is engaged with the external cylindrical surface of the eccentric, and a piston is connected to the connecting rod. An eccentric lever is attached to the eccentric. A compression ratio adjustment link is connected to the eccentric lever. A compression ratio adjustment mechanism is connected to the compression ratio adjustment link. The compression ratio adjustment mechanism controls the orientation of the connecting rod eccentric, and thereby the compression ratio of the engine, by extending or retracting the compression ratio adjustment link.