Hydraulic Variable-Compression Piston With Eccentric Pin Control
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Solution Overview
Problem
Fixed compression ratios in internal combustion engines lead to inefficient combustion at varying engine loads, resulting in partial combustion and reduced fuel efficiency due to the inability to adjust compression ratio dynamically.
Innovation Solution
A hydraulic variable compression ratio piston system that adjusts its position relative to the connecting rod through an eccentric piston pin, utilizing return springs and a contra-acting lifter to change compression ratio in response to combustion pressure, maintaining a fixed piston position and adapting to changes in engine load and power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed compression ratio is used in the engine, then the engine structure is simple, but combustion efficiency is reduced at varying engine loads due to partial combustion
Solution Approach 1:
The piston is designed with variable compression capability that dynamically adjusts the compression ratio based on engine load conditions. The piston can shift between different compression ratios (e.g., 12:1 for high load, 8:1 for low load) to optimize combustion efficiency across varying operating conditions, transforming a static component into a dynamic one that adapts to changing requirements.
2Productivity
If a traditional variable compression engine is implemented, then combustion efficiency is improved across all engine speeds, but device complexity and cost increase significantly
Solution Approach 1:
The variable compression mechanism is merged with the existing piston and connecting rod assembly. The piston incorporates an eccentric pin that rotates within the connecting rod, integrating the compression ratio adjustment function directly into the moving components rather than adding separate adjustment mechanisms. This merging approach enables variable compression capability while maintaining relative structural simplicity.
Solution Approach 2:
The system uses the existing combustion pressure and engine inertia to drive the eccentric pin rotation, which in turn adjusts the compression ratio. The combustion wave front pushing against the piston during the power stroke automatically causes the eccentric pin to rotate, creating a self-regulating system that adapts compression ratio based on real-time engine conditions without requiring external control systems.
3Adaptability or versatility
If the piston moves fully relative to the connecting rod, then compression ratio adjustment range is maximized, but harmful pre-detonation occurs at high compression ratios
Solution Approach 1:
The system dynamically changes the compression ratio parameter based on engine operating conditions. By adjusting the eccentric pin position, the compression ratio can be varied between 12:1 and 8:1, allowing the engine to optimize combustion efficiency at different loads while avoiding the harmful effects of excessively high compression ratios that would cause pre-detonation.
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
Enables full and efficient combustion across all engine speeds by dynamically adjusting the compression ratio, preventing pre-detonation and maintaining optimal engine performance without the complexity and cost of traditional variable compression engines.
Implementation Method 1
The function of the return springs, to return the eccentric to its original position, is opposed and controlled by the opposing lifter
Implementation Method 2
The lifter eventually loses oil and contracts, but very slowly at lower combustion and engine loads. At higher combustion and greater engine loads, the lifter expands as the return springs contract
Implementation Method 3
As the combustion wave front pushes against the piston, the piston shrinks down relative to the connecting rod, much like a shock absorber, to avoid harmful pre-detonation
Data Source
AI summary
The invention in question relates, in particular, to a hydraulic variable compression ratio piston comprising a full floating eccentric mounted in the body of said piston, wherein the eccentric accepts a piston pin, with the pin in turn, accepting the small end of the connecting rod. The eccentric moves in a circular manner against the force of preloaded springs installed at the bottom of the piston, thereby allowing the piston to move up or down relative to the connecting rod. An adjustment mechanism within the piston comprising of a combination of said preloaded springs and a lifter acting against the movement of the eccentric, holds the piston's current position relative to the connecting rod until an increase or decrease in combustion forces act upon the piston and changes the compression ratio.