Variable Compression Piston Rod Grooves for Compression Ratio Increase
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Solution Overview
Problem
In engine systems with compression adjustment devices, it is challenging to move the piston rod away from the bottom surface of the fluid chamber due to a small pressure receiving area, making it difficult to increase the compression ratio effectively.
Innovation Solution
A variable compression device with a grooved flow path on the bottom surface of the fluid chamber and a concave part on the piston rod, allowing the working fluid to flow into the grooved path and increase the contact area, facilitating the upward movement of the piston rod.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the piston rod is disposed on the bottom surface of the fluid chamber, then the structure is simplified, but the pressure receiving area becomes small making it difficult to move the piston rod upward
Solution Approach 1:
The invention introduces a grooved flow path that extends in the radial direction from the bottom surface of the fluid chamber toward the piston rod. This transforms the pressure application from a purely axial dimension to include radial dimension, allowing the working fluid to access the piston rod through both axial and radial pathways, thereby increasing the effective pressure receiving area without changing the basic bottom-surface disposal structure
2Adaptability or versatility
If the piston rod contacts the bottom surface of the fluid chamber, then the compression ratio can be minimized, but the working fluid cannot effectively push the piston rod upward to increase compression ratio
Solution Approach 1:
The grooved flow path acts as an intermediary structure between the working fluid and the piston rod. When the piston rod contacts the bottom surface, the grooved flow path provides an alternative pathway for the working fluid to flow radially and reach the piston rod's lateral surfaces, enabling continued upward movement even when axial contact occurs
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
The increased contact area with the working fluid enables easier upward movement of the piston rod, allowing for effective adjustment of the compression ratio even when the piston rod contacts the bottom surface, enhancing the engine's operational efficiency.
Implementation Method 1
a grooved flow path is formed in a bottom surface of the fluid chamber or a contact surface of the movable piston in contact with the bottom surface of the fluid chamber
Data Source
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AI summary
A variable compression device includes: a piston rod (6); and a fluid chamber (R3) in which, when a pressurized working fluid is supplied thereinto, the piston rod (6) is caused to move in a direction in which a compression ratio increases. A grooved flow path (R6) is formed in a bottom surface of the fluid chamber (R3) or a contact surface of the piston rod (6) in contact with the bottom surface of the fluid chamber (R3).