Manson engine

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The Manson engine is a hot air engine that was first described by A. D. Manson in the March 1952 issue of Newnes Practical Mechanics-Magazines. ^[1] Manson engines can be started in either direction (clockwise or anti-clockwise). ^[2] It has a stepped piston. The front part acts as a displacer and the back part acts as a work piston (the displacer and the work piston move as a single component). ^{[3] [1]} The engine only requires three moving parts: piston, ^[3] piston rod, and crank.

The engine is double acting, ^[1] using both the expansion of the warmed air and atmospheric pressure overcoming the reducing pressure of the cooling air to do work. ^{[3] [4] [5]}

The engine currently has no commercial or practical applications. The engines are built mainly as desk toys, physics demonstrations, and novelties. ^[2]

Functioning mechanism

Drawing based on the original design

ideal PV-Diagramm

• Phase 1 (cooling down the work medium, suction stroke)
  • when the Piston is moved toward the heat source, the hot gas inside the engine is moved to the cool side of the cylinder.
  • the gas is cooled there, resulting in pressure dropping below atmospheric, further moving the piston toward the heat source.
• Phase 2 (top dead centre)
  • When the piston reaches top dead centre, the inlet valve is open, releasing the vacuum.
  • the flywheel keeps the piston moving
• Phase 3 (heating up the work medium, expansion stroke)
  • when the piston is moving away from the heat source, the air is pushed toward the heat source.
  • the air is then heating up, resulting in the air expanding and the piston being further pushed away from the heat source
• Phase 4 (bottom dead centre)
  • when the piston reaches bottom dead centre, the exhaust valve is open, releasing the build up pressure and hot air.
  • the flywheel keeps the piston moving

Differences from Stirling engines

Stirling engines are typically closed systems, while Manson engines are open systems. ^{[3] [5] [8] [2]} The displacer and work piston of the Manson engine have zero phase angle. ^[4]

Variations

Manson-Ruppel-Engine

• Manson-Guise Engine

The valves and gas paths are considered by some to be complicated to manufacture, so various variants exist with improved, modified, or simplified valves and gas paths. ^{[9] [10]}

Sources

1. "The Manson experimental double acting engine". stirlingengines.org.uk.
2. "Nano Disc Manson-Guise Engine". stirlingengine.co.uk.
3. "Manson". techref.massmind.org.
4. "New generation of hot air engines: Manson engine". Archived from the original on 2019-09-13. Retrieved 2021-06-18. (gone)
5. "Manson". geocities.ws.
6. "Principes de fonctionnement du moteur Manson". December 22, 2018. Archived from the original on 2018-12-22.
7. "Manson-Motor". w-haag.de.
8. "A Novel Hot-air Engine" (PDF). Archived from the original (PDF) on 2021-06-24.
9. C2 DE 19904269 C2,Michael Ruppel,"Heißluftmotor - Heat engine has a simplified design with combined piston and valve and with alternate sides of the piston vented in either limits of the piston movement",published 2000-11-9,issued 2001-6-5 
10. GBapplication 2554458A,Christopher Guise,"Improvement to Manson engine",published 2000-11-09