Performance simulation of a non conventional gasoline MOD engine
Paper in proceeding, 2009

A new engine design concept, characterized by torroidal cylindrical cross section cylinders and rotating disc shape flat pistons instead of the conventional design has been developed by Markus Olofsson, Sweden. Such engine has neither crankshaft, nor connecting rods. A rotor in shape of the half-cylindrical torroid is covered by the other half of the static cylindrical torroid forming a new design for the combustion chamber. Such rotor is equipped with a fixed disc shape flat piston, while the other half-static torroid has a groove channel. Inside the groove a disc shape wall (which serves as a movable cylinder head) slides up and down in order to allow the bypass of the piston. The half-static torroid contains four different valve series for fresh air at low pressure, for air mixture at high pressure, for exhaust process and for high-pressure receiver filling. Each turn of the rotor (equipped with rotating piston) corresponds to four virtual stroke processes. Thus, a full engine cycle is developed for a single non-conventional driving shaft revolution. Having separate combustion and compression chambers at both sides of the flat piston, the new design is believed to have the potential to provide typical engine performance. Therefore, it has been subjected to an engine thermodynamics simulation, to provide an insight to engine performance. Simulation results and preliminary evaluations have shown that the further work for optimization of the torroid-rotating piston engine parameters might lead to a compact and lower friction engine. Lower friction performance might be due to the crankshaft and connecting rod missing, which are normally the main components for the friction losses. Further reduction of the friction losses might come from the rotating pistons, which do not have any side force as in the conventional reciprocating engine. Therefore, the new developed design would lead to the reduction of the engine vibrations and noise level. Since the torroidal cylinder-rotating piston engine promises to display good performance and reduced size compared to conventional combustion engines, the new engine design concept should be further investigated and compared with other conventional engines.


Savo Gjirja

Chalmers, Applied Mechanics, Combustion and Propulsion Systems

Erik Olsson

SAE Technical Papers

01487191 (ISSN) 26883627 (eISSN)

SAE World Congress and Exhibition
Detroit, USA,

Subject Categories

Mechanical Engineering



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