The present invention concerns an air motor comprising a piston and a housing, the piston being received in the housing and dividing the housing into two primary chambers of variable volume. Said motor comprises a first direct supply valve for supplying a first primary chamber of the two primary chambers and a second direct supply valve for supplying the other primary chamber, said two valves each being movable relative to at least one respective seat. The first valve and the second valve are mounted on a same stem movable relative to the housing in a direction parallel to the direction of movement of the piston, and the stem is configured to be moved between a first position and a second position by moving means activated by the piston.

Systems and methods are disclosed of an engine driven power system that includes a permanent magnet generator electrically connected to an energy storage device. An air compressor is coupled to the permanent magnet generator via a clutch. A controller provides power from the energy storage device to the permanent magnet generator to turn the permanent magnet generator to drive the air compressor via the clutch to increase an air pressure level.

A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: receiving at least a first signal; determining a quantity of liquid air to be injected using at least the received first signal; controlling injection of the determined quantity of liquid air into the first end of the cavity at a first time when the piston is closer to the first end than the second end.

A method of controlling a reciprocating internal combustion engine comprising: a cylinder defining a cavity having a first end and a second end; and a piston moveable within the cavity of the cylinder between the first end and the second end, the method comprising: controlling injection of a quantity of liquid air, without fuel, into the first end of the cavity at a first time when the piston is closer to the first end than the second end to cause the piston to perform a first power stroke; and controlling injection of fuel into the first end of the cavity at a second time when the piston is closer to the first end than the second end to cause the piston to perform a second power stroke.

An engine and corresponding driving propulsion system may provide continuous force necessary to keep the engine operating. Utilizing two pressurized tanks with high and low pressures may provide a continuous flow of pressure to the engine necessary for it to operate.

Methods of laser powering unmanned aerial vehicles (UAV) with heat engines are disclosed. The laser powered heat engines are used in conjunction with devices for absorbing laser optical radiation, turning the laser optical radiation into heat, supplying the heat to a working fluid of the heat engine and harvesting mechanical work from expanding working fluid in the heat engine.