Digital Hydraulic Opposed Free Piston Engine Vibration Control
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Solution Overview
Problem
Hydraulic free piston engines experience significant vibration due to the reciprocating motion of combustion pistons, which limits the operational efficiency and mechanical energy extraction.
Innovation Solution
The engines are designed with paired free pistons arranged in a configuration where their axes of motion are parallel or co-linear, with a controller managing their equal and opposite motions to balance forces and reduce vibration, utilizing three-way valves to efficiently switch between high and low pressure rails and a reservoir for optimal energy conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If hydraulic free piston engines use reciprocating combustion pistons for energy conversion, then chemical to hydraulic energy conversion is achieved, but significant vibration is generated
Solution Approach 1:
The patent employs opposed pistons that move in opposite directions within their respective cylinders. The reciprocating motion of one piston generates forces that are counterbalanced by the opposing piston, effectively canceling out vibration and harmful dynamic loads on the engine structure while maintaining continuous energy conversion.
Solution Approach 2:
The patent combines two piston-cylinder assemblies into a single integrated unit where both pistons share common combustion and exhaust manifolds. This merging allows the system to achieve balanced operation while reducing overall structural complexity and improving thermal efficiency through integrated heat management.
2Adaptability or versatility
If free piston motion is used without crankshaft, then operational flexibility is improved, but vibration control becomes difficult
Solution Approach 1:
The opposed piston configuration provides inherent vibration cancellation through counterbalancing forces, enabling the engine to maintain operational flexibility without crankshaft constraints while simultaneously controlling vibration through the natural opposition of piston motions.
Solution Approach 2:
The patent incorporates electronic control systems with sensors that monitor piston position, combustion parameters, and vibration levels in real-time. The controller adjusts fuel injection timing and quantity, valve actuation, and hydraulic pressure to optimize performance and minimize vibration, creating a closed-loop feedback system that maintains operational flexibility.
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 significantly reduces vibration and enhances the efficiency of chemical to hydraulic energy conversion by allowing each piston to operate at its most efficient phase, balancing forces, and optimizing energy extraction.
Implementation Method 1
converting the energy in petrochemical fuels such as gasoline or diesel fuel to rotary mechanical energy by using the pressure created by confined combustion
Implementation Method 2
Hydraulic free piston engines couple the combustion free piston to a hydraulic cylinder that acts as both the load and rebound device using a hydraulic control system
Data Source
AI summary
Digital hydraulic opposed free piston internal combustion engines having a pair of free pistons in a pair of cylinders defining a combustion chamber above each free piston. The pair of free pistons is arranged to move within the pair of cylinders with parallel axes of free piston motion, and preferably co-linear axes of free piston motion. At least one hydraulic plunger is under each free piston with each hydraulic plunger in a respective hydraulic cylinder. The hydraulic cylinders are coupled to electronically controlled hydraulic cylinder valving. A controller controls the electronically controlled hydraulic cylinder valving to control the pair of free pistons to have substantially equal and opposite motions.