Variable Compression Piston Rod Damping With Bypass Fluid Channel
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Solution Overview
Problem
Existing variable compression devices face challenges in stably supplying working fluid to an upper space, which is essential for absorbing collision energy between the regulation member and piston rod, due to difficulties in fluid supply through a sealed portion between the piston rod and fluid chamber forming member.
Innovation Solution
A variable compression device with a fluid chamber forming member and sliding rings, where a communication channel guides working fluid from a lower space to an upper space, bypassing the sliding ring, and includes an adjustment unit, such as a reduced diameter portion or check valve, to control fluid flow, ensuring stable fluid supply and energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sliding ring seals the portion between the piston rod and fluid chamber forming member, then sealing performance is improved, but stable supply of working fluid to the upper space deteriorates
Solution Approach 1:
The fluid chamber is segmented into a lower space and an upper space by the sliding ring, with the communication channel providing a dedicated fluid supply path from the lower space to the upper space. This segmentation allows the sliding ring to maintain sealing while the communication channel ensures stable fluid supply to the upper space.
Solution Approach 2:
The communication channel acts as an intermediary pathway that bypasses the sliding ring seal. It provides a separate route for working fluid to reach the upper space without compromising the sealing function of the sliding ring, thus resolving the contradiction between sealing and fluid supply.
2Ease of operation
If the piston rod moves in a state where combustion pressure is not generated, then engine starting is enabled, but collision between the piston rod and regulation member occurs
Solution Approach 1:
The upper space is pre-filled with working fluid before the piston rod moves during engine starting. This working fluid acts as a cushion that absorbs collision energy when the piston rod contacts the regulation member, preventing damage while allowing engine starting without combustion pressure.
Solution Approach 2:
The patent uses hydraulic principles by filling the upper space with working fluid that functions as a damper. The incompressible nature of the hydraulic fluid provides immediate cushioning force to absorb collision energy, enabling safe engine starting operations.
3Strength
If working fluid is stored in the upper space to absorb collision energy, then collision damage is prevented, but stable fluid supply becomes difficult
Solution Approach 1:
The fluid chamber is divided into lower and upper spaces, with the lower space serving as the primary fluid reservoir and the upper space serving as the collision absorption zone. The communication channel connects these segments, ensuring stable fluid supply to the upper space while maintaining sufficient fluid volume for energy absorption.
Solution Approach 2:
The working fluid serves multiple functions simultaneously: it acts as a coolant, provides hydraulic pressure for compression ratio adjustment, and functions as a damper to absorb collision energy. The communication channel ensures all these functions are maintained by providing stable fluid supply to the upper space.
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 configuration allows for stable working fluid supply to the upper space, effectively absorbing collision energy between the regulation member and piston rod, preventing collisions and maintaining appropriate fluid levels.
Implementation Method 1
absorbing collision energy between the regulation member and the piston rod by storing a working fluid in a space (upper space) between the regulation member and the piston rod and causing the working fluid to function as a damper
Implementation Method 2
the fluid chamber forming member includes a communication channel that is configured to guide a portion of the working fluid, which is supplied to the lower space as a coolant, to the upper space
Implementation Method 3
a portion between the piston rod and a fluid chamber forming member is sealed by a sliding ring
Data Source
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AI summary
A variable compression device of the present disclosure includes: a piston rod (6); a fluid chamber forming member (7a) which forms a portion of a fluid chamber (R3) configured to move the piston rod in a direction in which a compression ratio is increased by supplying a boosted working fluid thereto; a regulation member (7c) which is configured to regulate movement of the piston rod in a direction in which a compression ratio is increased; and a sliding ring (6d) which is provided on a circumferential surface of the piston rod to be slidable with respect to the fluid chamber forming member, in which a lower space (R7) surrounded by the fluid chamber forming member and the piston rod is formed below the sliding ring, an upper space (R6) surrounded by the fluid chamber forming member, the piston rod, and the regulation member is formed above the sliding ring, and the fluid chamber forming member includes a communication channel (R11) that is configured to guide a portion of the working fluid, which is supplied to the lower space as a coolant, to the upper space.