Stirling Engine Rocking Beam Drive Reduces Piston Side Loads
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing Stirling cycle machines face challenges with friction and side loads due to piston misalignment and lateral forces, leading to increased noise, reduced efficiency, and shorter engine life, and existing improvements result in heavier and bulkier machines.
Innovation Solution
The implementation of a rocking beam drive mechanism with a crankcase and connecting rod system that converts linear piston motion to rotary motion, utilizing a rolling diaphragm seal and a bidirectional pressure regulator to maintain pressure differential and reduce side loads, along with a lubricating fluid pump to minimize friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a traditional piston and crankshaft drive mechanism is used, then rotary motion is produced, but side loads and friction increase due to piston misalignment and lateral forces
Solution Approach 1:
A rocking beam is introduced as an intermediary component between the linearly reciprocating piston and the rotary crankshaft. The rocking beam converts linear piston motion into rotary motion while minimizing side loads on the piston through its specific geometric configuration and pivot arrangement, thereby reducing friction and piston wear while maintaining power output
2Reliability
If drive mechanism improvements are made to reduce side loads, then piston friction decreases, but the machine becomes heavier and bulkier
Solution Approach 1:
The rocking beam mechanism changes the geometric parameters of the drive system, specifically the arrangement of pivots and beam dimensions, to achieve optimal side load reduction. This parameter optimization allows for reduced friction and improved reliability while maintaining a compact and lightweight design, avoiding the penalty of increased machine weight
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 solution reduces side loads on pistons, enhances efficiency, and extends engine life while maintaining a compact design by effectively converting linear motion to rotary motion and managing pressure differentials, thus addressing the friction and alignment issues in Stirling cycle machines.
Implementation Method 1
an airlock space separating the crankcase and the working space for maintaining a pressure differential between the crankcase housing and the working space housing
Implementation Method 2
an airlock pressure regulator connected between the crankcase and one of the airlock space and working space
Implementation Method 3
a rocking beam rotating about a rocker pivot for driving the crankshaft, a piston rod connected to the piston, a rocking beam driven by the piston rod
Implementation Method 4
a connecting rod connected at a first end to the rocking beam and at a second end to a crankshaft to convert rotary motion of the rocking beam to rotary motion of the crankshaft
Implementation Method 5
along with a lubricating fluid pump to minimize friction
Implementation Method 6
a burner element for heating the working fluid of the engine
Implementation Method 7
at least one heater head defining a working space containing the working fluid
Implementation Method 8
at least one heater head defining a working space containing the working fluid
Implementation Method 9
a cooler for cooling the working fluid
Data Source
AI summary
An external combustion engine is disclosed. The external combustion engine includes a working fluid and a burner element, at least one heater head defining a working space, at least one piston cylinder containing a piston, a cooler, a crankcase including a crankshaft for producing an engine output, a rocking beam, a piston rod connected to the piston, a rocking beam driven by the piston rod, and a connecting rod connected at a first end to the rocking beam and at a second end to a crankshaft to convert rotary motion of the rocking beam to rotary motion of the crankshaft. The external combustion engine also includes an airlock space separating the crankcase and the working space for maintaining a pressure differential between the crankcase housing and the working space housing and an airlock pressure regulator connected between the crankcase and one of the airlock space and working space.