External Combustion Engine Power Modulation via Cylinder Phasing
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Solution Overview
Problem
Existing external combustion engines, such as Stirling engines, lack the ability to modulate power output, limiting their application to only continuous and constant energy delivery, making them unsuitable for traction or propulsion applications requiring variable power.
Innovation Solution
The engine design includes two cylinders kinematically connected to a drive shaft with movable support frames, allowing for variation in phasing and work capacity, enabling power modulation through controlled movement means, such as electric actuators and position transducers, to adjust the relative position of the cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single cylinder is used in external combustion engines, then the structure is simple, but the power cannot be modulated
Solution Approach 1:
The engine is divided into multiple independent cylinders (first cylinder and second cylinder) that can be independently controlled. Each cylinder can be positioned at different angular locations around the drive shaft, allowing independent adjustment of their contribution to the total power output, thereby enabling power modulation while maintaining structural simplicity through modular design
Solution Approach 2:
The cylinders are mounted on movable support frames that allow dynamic adjustment of the cylinders' angular positions relative to the drive shaft. This dynamic reconfigurability enables the engine to modulate its power output by changing the operational phase and contribution of each cylinder, transforming a static single-power-level engine into a dynamically adjustable multi-power-level system
2Adaptability or versatility
If cylinders are fixed in position, then the structure is stable, but the power delivery cannot be varied
Solution Approach 1:
The support frames are designed with movable connections to the drive shaft, allowing the cylinders to be positioned at different angular locations. This dynamic positioning capability enables variation in power delivery by adjusting which cylinders are active and their relative phasing, while the movable support frame mechanism maintains structural stability during operation
Solution Approach 2:
The support frame mechanism serves multiple functions: it provides structural support for the cylinders, enables angular positioning adjustment for power modulation, and maintains stable operation during engine running. This multi-functionality reduces the need for additional separate mechanisms, thereby limiting the increase in device complexity
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 allows for coordinated variations in torque delivery, enabling the engine to be used in applications requiring continuous power variations, such as traction or propulsion, while maintaining the advantages of external combustion engines like silence and low environmental impact.
Implementation Method 1
an external combustion engine, such as for example a Stirling engine, which exploits a cycle of isothermal expansion and compression of a thermodynamic fluid
Implementation Method 2
the expansion chamber is heated by means of a heater member, for example a burner, a resistance or other
Implementation Method 3
the expansion chamber is heated by means of an external heat-carrying fluid, circulating for example in a pipe disposed around the expansion chamber
Implementation Method 4
the compression chamber is cooled by means of an external heat-carrying fluid
Data Source
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AI summary
External combustion engine (10) comprising a drive shaft (13), a first cylinder (11) kinematically connected to the drive shaft (13), a second cylinder (12) kinematically connected to the drive shaft (13), and a thermodynamic circuit (15) fluidly connected to both the cylinders (11, 12), and having at least an expansion chamber (22) and a compression chamber (18, 23) for a heat-carrying fluid, in order to determine the cyclic movement of the first cylinder (11) and the second cylinder (12). The first cylinder (11) is mounted on a first support frame (20) and the second cylinder (12) is mounted on a second support frame (26), distinct from and constrained in a mobile manner to the first support frame (20). Movement means (27) are mechanically connected to the first support frame (20) and/or the second support frame (26), in order to determine the desired relative movement of the first support frame (20) and the second support frame (26) and to vary the reciprocal kinematic connection phasing of the two cylinders (11, 12) with respect to the drive shaft (13).