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Stirling engine

Ce site appartient au réseau de sites relatifs aux moteurs à air chaud

Stirling engine
Beta model or rhombic-drive engine

This page shows a constructive example of a Beta Stirling engine. It has been the subject of a first approach, in the page “the principles”.

1. The four basic stages :

Compared to the ideal cycle described in the page "The principles", the different phases of the cycle of a beta engine are less differentiated. However, the following drawings seek to represent them.

1.1. Heating :

Heating Heating Heating

The gas is transferred from the cold part towards the hot part.
- the operating piston is almost motionless.
- the displacer goes down.

1.2. Expansion :

Expansion Expansion Expansion

It is the expansion phase, the gaz is near the hot part.
- the operating piston goes down.
- the displacer too.

1.3. Cooling :

Cooling Cooling Cooling

The gas is transferred from the hot part towards the cold part.
- the operating piston is almost motionless.
- the displacer goes up.

1.4. Compression :

Compression Compression Compression

The gas is compressed, it is near the cold part.
- the operating piston goes up.
- the displacer is almost motionless at the top.

The following animation shows the complete cycle of a beta engine:

Animation of the complete cycle of a beta engine

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2. The PV diagram :

2.1. The volume variations :

Volume variations

On the diagram above, one can see :
- the variations of hot volume (red area).
- the variations of cold volume (blue area).

2.2. The PV diagram :

PV diagram


This diagram is characteristic of the engine described above.
The calculations were made with TM = 2 Tm.
The theoretical efficiency would be 0.5.
One can see that this cycle is clearly different from the theoretical cycle. But it is similar.
The important thing is to have the gray area as large as possible. It is representative of the work recovered during a cycle (see the page ."the principles").

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This site was created and is maintained by Pierre Gras. Thank you with all the people who contributed their shares: articles, photographs, vidéos, worksheets… The author is opened with any suggestion allowing to improve this site for happiness of everybody. Finally, a big thank you to Robert Stirling !

"stirlinengine.fr" site by Pierre Gras is licensed under a Creative Commons License Creative Commons License .

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