| Propulsion

Rotary Piston Engine

There are many applications where a high power-to-weight engine is either necessary or helpful. Uses for this type of engine range from handheld power equipment, to motorcycles and aircraft — uses multiply when fuel efficiency, compactness, and versatility are added. Currently, there are few viable options available to fulfill these applications, and those that are available are very inefficient when high power is no longer desired. When the application warrants it, the engine type of choice has been the turbine engine.

Turbine engines are only efficient while high power is desired (heavy lift/movement and/or high speed), becoming very wasteful outside of their design load. Turbine engines often are not economical due to their high manufacturing costs and poor fuel efficiency. Internal combustion engines are much more fuel-efficient at off-peak performance, but currently lack the power-to-weight ratio of turbine engines. Internal combustion engines use readily available fuel to drive them, and are practical for many applications. They are relatively economical to manufacture, reach peak power from idle relatively quickly, and have relatively low heat and noise signatures.

There is a need for a high-power-density engine that is lightweight, fuel-efficient, compact, and versatile.

This invention is a rotary piston engine comprising at least one tows-shaped cylinder defined by an outer wall formed around an exterior circumferential surface of the tows, and a rotor formed around an interior circumferential surface of the torus. The invention includes at least one piston connected to the rotor, at least one compression tunnel for storing compressed gas, an intake port disposed through the outer wall for each wall valve, an exhaust port disposed through the outer wall for each wall valve, at least one wall valve mechanism disposed in the outer wall with each wall valve mechanism located between an intake port and an exhaust port, and an inflow port and outflow port for each piston. Each inflow and outflow port is adapted to fluidly communicate a cylinder with a compression tunnel. The rotor is connected to the drive shaft with at least one spoke, and disposes a fuel port and a spark port between an intake port and the corresponding wall valve mechanism.

The rotary piston engine combines most of the advantages of an internal combustion engine with those of a turbine engine. The rotary piston engine improves on the existing internal combustion and turbine technology by achieving the same or better high-end performance, while improving the efficiency during off-peak operations.

For more information, contact Amanda Horansky-McKinney at amanda.mckinney@ nrl.navy.mil; 202-767-5815.