Stirling Engine Rocking Beam Linkage for Low-Side-Load Pistons
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Solution Overview
Problem
Stirling cycle machines face challenges due to friction and side loads from misaligned pistons, leading to increased noise, reduced efficiency, and shorter engine life, with existing improvements resulting in heavier and bulkier machines.
Innovation Solution
A rocking beam drive mechanism that converts linear piston motion to rotary motion, using a rocking beam with a rocker pivot, coupling assemblies, and a crankshaft, minimizing side loads through linear bearings and flexible coupling means like roller bearings or flexures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional piston and crankshaft linkage is used, then rotary motion is achieved, but side loads and friction increase leading to reduced efficiency and shorter engine life
Solution Approach 1:
The drive mechanism is divided into separate functional components: a rocking beam for motion conversion, linear bearings for guidance, and flexible coupling means for connection. This segmentation allows each component to perform its specific function optimally, reducing overall side loads and friction on the piston
Solution Approach 2:
The rocking beam acts as an intermediary between the piston and crankshaft, converting linear piston motion to rotary motion through rocking motion about a pivot point. This intermediate conversion mechanism eliminates the need for traditional connecting rod linkages that generate harmful side loads
2Loss of energy
If drive mechanisms are modified to reduce side loads, then efficiency improves, but machine weight and bulk increase
Solution Approach 1:
Instead of using a traditional crankshaft-driven mechanism that pulls pistons through lateral forces, this invention inverts the approach by using a rocking beam that naturally converts linear motion to rotary motion through its pivot geometry, eliminating the need for heavy lateral support structures
Solution Approach 2:
The mechanism changes the motion parameters from direct rotary-crank linkage to rocking-beam angular motion, allowing for a more compact and lighter design while maintaining efficient energy transfer and minimizing side loads
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 solution reduces side loads on pistons, enhancing the efficiency and lifespan of Stirling cycle machines while maintaining a compact design, by ensuring linear motion is maintained with minimal angular deviation, thus reducing friction and noise.
Implementation Method 1
a rocking beam having a rocker pivot... The linear motion of the piston is converted to rotary motion of the rocking beam
Implementation Method 2
The cylinder may further include a closed end and an open end. The open end further includes a linear bearing connected to the cylinder
Implementation Method 3
The coupling means is a roller bearing
Implementation Method 4
The coupling means is a flexure
Data Source
AI summary
A Stirling cycle machine with a liquid fuel/gaseous fuel burner. The burner may include a preheater to capture the thermal energy of the exhaust. The burner directs the preheated air to each burner head, where it enters a prechamber. Each burner head includes a fuel nozzle that directs liquid or gaseous fuel into the prechamber. The prechamber is fluidically connected to a combustion chamber via a prechamber nozzle that has a smaller opening than the prechamber. The burner head ignites the fuel air mixture in the prechamber with an ignitor located above or within the prechamber. The flame is initially lit as a diffusion flame in the prechamber. The flame is pushed out of the prechamber into the combustion chamber by an increased air flow rate. The liquid fuel from the nozzle now evaporates in the prechamber and forms a prevaporized flame in the combustion chamber.