Single Shaft Dual Expansion Engine Vibration Control
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Solution Overview
Problem
Internal combustion engines face inefficiencies due to energy losses and vibrations, which are not adequately addressed by traditional four-stroke cycles and balance shafts, particularly in maximizing energy extraction and minimizing mechanical and flow losses.
Innovation Solution
A single-shaft dual expansion internal combustion engine design featuring a multi-link connecting rod assembly, dual balance shafts with counterweights, and a compound cylinder configuration that allows for offset piston motion and phasing control, optimizing energy extraction and balancing first-order vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional four-stroke cycle is used, then engine operation is simplified, but energy extraction efficiency is reduced
Solution Approach 1:
The engine cycle is divided into separate compression and expansion phases, with the expansion phase further segmented into two strokes. This allows each phase to be optimized independently, maximizing energy extraction while managing complexity through functional separation.
Solution Approach 2:
The engine employs a periodic two-stroke expansion cycle where the expansion process is repeated in two distinct strokes rather than one. This periodic action allows for more complete energy extraction from the combustion gases while maintaining a manageable operational rhythm.
2Object-affected harmful factors
If balance shafts are added to reduce vibrations, then vibration control improves, but device complexity increases
Solution Approach 1:
Balance shafts with counterweights are installed within the engine block to generate counterbalancing forces that offset the vibrations produced by the asymmetrical cylinder configuration. This directly addresses the harmful vibrations while integrating the balancing mechanism into the existing engine structure.
Solution Approach 2:
The balance shafts are mounted within the engine block and driven through a chain or gear system that is already rotationally coupled to the engine. This merging of the balancing mechanism with the existing engine components minimizes additional complexity while achieving effective vibration control.
3Use of energy by moving object
If mid-compression heat extraction is implemented, then compression efficiency improves, but device complexity increases
Solution Approach 1:
A heat exchanger is introduced as an intermediary component that extracts heat from the compressed gas during the mid-compression phase. This mediator allows for efficient heat transfer and energy recovery without directly interfering with the compression process, thereby improving compression efficiency while adding a manageable level of complexity.
4Power
If expansion is extended to atmospheric pressure, then energy harnessed increases, but mechanical losses increase
Solution Approach 1:
The expansion process is extended continuously over two strokes, allowing the working gases to expand as far as possible down to atmospheric pressure. This continuous useful action maximizes the energy harnessed from the combustion process while the system is designed to minimize associated mechanical and flow losses.
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 design enhances energy extraction efficiency, reduces mechanical and flow losses, and provides effective balancing of vibrations, leading to improved engine performance with a more compact and efficient layout.
Implementation Method 1
Balance shafts may be mounted in the engine block, and driven at a rotational speed that is double the engine speed employing a chain, gear or belt that is rotationally coupled to the engine. Balance shafts employ counterweights that are timed to cancel the second-order vibrations in the engine.
Implementation Method 2
Balance shafts employ counterweights that are timed to cancel the second-order vibrations in the engine.
Implementation Method 3
Internal combustion engines combust mixtures of air and fuel to generate mechanical power for work.
Data Source
AI summary
A single-shaft dual expansion internal combustion engine includes an engine block, a cylinder head and a crankshaft. First and second power pistons are moveable in first and second power cylinders and are connected to first and second crankpins of the crankshaft. An expander piston is moveable in an expander cylinder and is connected via a multi-link connecting rod assembly to a third crankpin of the crankshaft. A first balance shaft is arranged in a first longitudinal opening in the engine block, and a second balance shaft is arranged in a second longitudinal opening in the engine block. The first and second balance shafts have first and second counterweight portions, respectively, and the crankshaft has a third counterweight portion causing an imbalance in the crankshaft.