Free-Piston Stirling Engine Dual-Spring Displacer Support
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Solution Overview
Problem
The existing free-piston Stirling engine is limited to a perpendicular installation due to unstable reciprocation of the displacer and power piston caused by excessive friction when installed at an angle, leading to tilting and resistance issues.
Innovation Solution
The engine employs a dual elastic supporting system, with a first elastic supporting member supporting the displacer and its rod at the proximal end and a second supporting member supporting the rod at the distal end, maintaining an airtight communication hole to allow phase-different reciprocation and prevent tilting, ensuring stability regardless of installation orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the displacer is supported in a lower portion of the housing in a cantilevered manner by a spring, then the structure is simple and easy to manufacture, but the displacer and rod portion tilt causing excessive friction and unstable reciprocation when installed at an angle
Solution Approach 1:
The single cantilevered spring support is segmented into two separate elastic supporting members: a first elastic supporting member (spring) that supports the proximal end of the displacer rod in the first space, and a second elastic supporting member (spring) that supports the distal end of the displacer rod in the second space. This segmentation allows each spring to independently provide support and restore the displacer rod to its initial position, preventing tilting and ensuring stable reciprocation regardless of installation angle while maintaining structural simplicity.
2Device complexity
If the displacer is supported by a single spring in a cantilevered manner, then the device complexity is low, but friction between the displacer and housing increases causing reciprocation to stop
Solution Approach 1:
The support system is divided into two separate elastic supporting members positioned in different spaces. The first spring supports the proximal end of the displacer rod while the second spring supports the distal end, creating a balanced support system that prevents the displacer rod from tilting against the housing walls, thereby minimizing friction resistance and preventing reciprocation stoppage.
Solution Approach 2:
The two elastic supporting members work in opposition to each other, with the first spring counterbalancing the second spring to maintain the displacer rod in a neutral, non-tilted position. This counterbalancing action ensures that the displacer rod remains centered in the housing, reducing contact and friction with the housing walls during reciprocation.
3Reliability
If the engine is installed perpendicular to the ground, then the single spring support system works reliably, but the installed state is limited and cannot accommodate other angles
Solution Approach 1:
The dual spring support system creates a balanced configuration where the first and second elastic supporting members counterbalance each other's forces. This counterbalancing mechanism automatically adjusts to maintain the displacer rod in a stable, non-tilted position regardless of the engine's installation angle, enabling reliable operation in vertical, horizontal, or inclined positions without requiring reconfiguration.
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 reciprocation of the displacer and power piston across various installation angles, eliminating the restriction on the engine's installation state and maintaining operational stability.
Implementation Method 1
The first elastic supporting member is arranged in the first space and elastically supports at least one of the displacer and the displacer rod at its proximal end in the case. The second elastic supporting member is arranged in the second space and elastically supports the displacer rod at its distal end in the case.
Implementation Method 2
the power piston and the displacer reciprocate respectively along the predetermined axis with a predetermined phase difference therebetween, by means of the working gas in the first space being expanded and compressed by cooling and heating
Data Source
AI summary
A free-piston type stirling engine 1 includes a power piston 30 which partitions the inside of a case 2 into a work space 80 and a bounce space 90, a displacer 40, a communication hole 32 provided in the power piston 30, a displacer rod 41 extending from the displacer 40 and passing through the communication hole 32, a first displacer supporting spring 50 elastically supporting the displacer rod 41 at its proximal end, and a second displacer supporting spring 60 elastically supporting the displacer rod 41 at its distal end. The power piston 30 and the displacer 40 reciprocate along a central axis X of the case 2 with a phase difference therebetween by expansion and compression of a working gas in the work space 80, and bias forces of the first displacer supporting spring 50 and the second displacer supporting spring 60 restrict tilting of the displacer 40 and the displacer rod 41 with respect to the central axis X.