A quasiturbine is a rotary engine concept incorporating a central rotor made from four hinged elements. The elements take the form of blades in simple designs and involve the use of wheeled carriages in more complex versions. The rotor elements seal against the interior of an oval housing, dividing it into four chambers. Ports arranged sequentially around the housing allow for the intake, compression, combustion and exhaust cycle. The design provides for nearly continuous turbine-like combustion with four cycles for every turn of the rotor.
The wheeled carriage design makes the engine more sturdy and able to withstand the demands of very high compression ratios such as in photo-detonation. This is a pressure-heated self-ignition of fuel unsuited to piston engines or Wankel type rotary engines. Photo-detonation completely consumes the fuel and no hydrocarbon pollutants are produced. Less fuel is required for combustion, resulting in improved fuel efficiency. One of the objectives in the continuing development of the engine is to produce a working prototype that makes effective use of this type of combustion.
Functioning models of the quasiturbine have been demonstrated as a pneumatic engine running on compressed air, and as a steam engine. Other proposed applications for the design include use as a turbocharger, a compressor or a pump. A virtually vibration free pneumatic design is used to power a chain saw that is under commercial development.
The quasiturbine concept was developed by a research group under the direction of Dr. Gilles Saint-Hilaire in 1996. Patents for the device are held by the Saint-Hilaire family. The design evolved from a critical reassessment of the internal combustion engine as it is currently implemented. Increased fuel efficiency and lower exhaust emissions as an inherent part of the design were central tenets of the project.
Advantages of the quasiturbine design include a much more efficient combustion chamber than in a Wankel type rotary engine. Fuel is more completely burned, delivering better fuel efficiency with less pollution. The engine has excellent balance and is essentially vibration free. It has higher torque at lower revolutions per minute (RPM) than other engines and has the potential for faster acceleration without the use of a flywheel. The quasiturbine does not need a crankshaft, operates nearly oil-free and has fewer moving parts than most internal combustion engines.
The engine is designed to run on gasoline, kerosene, diesel or natural gas. It could be adapted for hydrogen fuels with little modification. These features are contained in a compact and lightweight structure making for easy installation and repair. The disadvantages of a quasiturbine arise from its early, conceptual stage of development. There are also other engine designs that show the potential for equal or superior efficiency.