An engine configuration that uses multiple opposing piston pairs to form respective expansion chambers for expanding a gas within to move the pistons to drive a main shaft. The engine can be configured to operate as an internal combustion engine that uses diesel fuel, gasoline, or natural gas, or it can be configured as an expander to convert high pressure high temperature gas to rotary power. The pistons may be mounted on the circumference of one or more disks. For any given set of choices of numbers of pistons and sizes of pistons, disks, and gears, there are disclosed dimensional constraints useful for more efficient functioning of the engine. This engine can be provided with a compact design which results in high power to weight ratios.

An engine configuration that uses multiple opposing piston pairs to form respective expansion chambers for expanding a gas within to move the pistons to drive a main shaft. The engine can be configured to operate as an internal combustion engine that uses diesel fuel, gasoline, or natural gas, or it can be configured as an expander to convert high pressure high temperature gas to rotary power. The pistons may be mounted on the circumference of one or more disks. For any given set of choices of numbers of pistons and sizes of pistons, disks, and gears, there are disclosed dimensional constraints useful for more efficient functioning of the engine. This engine can be provided with a compact design which results in high power to weight ratios.

In one aspect, described is a rotary engine having a purge port located rearwardly of the inlet port and forwardly of the exhaust port along a direction of the revolutions of the rotor, the purge port being in communication with the exhaust port through each of the chambers along a respective portion of each revolution, and the inlet and outlet ports being relatively located such that a volumetric compression ratio of the engine is lower than a volumetric expansion ratio of the engine.

In one aspect, described is a rotary engine having a purge port located rearwardly of the inlet port and forwardly of the exhaust port along a direction of the revolutions of the rotor, the purge port being in communication with the exhaust port through each of the chambers along a respective portion of each revolution, and the inlet and outlet ports being relatively located such that a volumetric compression ratio of the engine is lower than a volumetric expansion ratio of the engine.

A method of controlling an air intake flow in a rotary engine having primary and secondary inlet ports, including positioning the secondary inlet port rearwardly of the primary inlet port and forwardly of the exhaust port along a direction of a revolution of the rotor, providing independently closable communications between an air source and the primary and secondary inlet ports, and controlling air intake flows between the air source and the primary and secondary inlet ports. Controlling air intake flows includes simultaneously allowing the air intake flow between the primary inlet port and the air source and between the secondary inlet port and the air source. Exhaust gases of the engine are purged with the air intake flow of the secondary inlet port. A rotary engine is also discussed.

A method of controlling an air intake flow in a rotary engine having primary and secondary inlet ports, including positioning the secondary inlet port rearwardly of the primary inlet port and forwardly of the exhaust port along a direction of a revolution of the rotor, providing independently closable communications between an air source and the primary and secondary inlet ports, and controlling air intake flows between the air source and the primary and secondary inlet ports. Controlling air intake flows includes simultaneously allowing the air intake flow between the primary inlet port and the air source and between the secondary inlet port and the air source. Exhaust gases of the engine are purged with the air intake flow of the secondary inlet port. A rotary engine is also discussed.

A rotary drive apparatus includes a housing, within which is located a first rotor and second rotor. The first rotor is rotatable about a first axis and has a rotor element projecting radially therefrom. The second rotor is rotatable about a second axis parallel to the first axis and in a direction opposite to the first rotor. The second rotor includes a recess able to receive the rotor element. The first rotor and the second rotor and housing define a chamber around the first rotor through which the rotor element passes. The chamber has an inlet and an outlet through which a fluid can enter and exit the chamber.

A rotary drive apparatus includes a housing, within which is located a first rotor and second rotor. The first rotor is rotatable about a first axis and has a rotor element projecting radially therefrom. The second rotor is rotatable about a second axis parallel to the first axis and in a direction opposite to the first rotor. The second rotor includes a recess able to receive the rotor element. The first rotor and the second rotor and housing define a chamber around the first rotor through which the rotor element passes. The chamber has an inlet and an outlet through which a fluid can enter and exit the chamber.

A method of controlling an air intake flow in a rotary engine having primary and secondary inlet ports, including positioning the secondary inlet port rearwardly of the primary inlet port and forwardly of the exhaust port along a direction of a revolution of the rotor, and controlling air intake flows communicating between an air source and the primary and secondary inlet ports. During engine start-up, a primary valve is closed to prevent the intake air flow between the primary inlet port and the air source and a secondary valve is opened to allow the intake air flow between the secondary inlet port and the air source. A rotary engine defining different compression ratios through actuation of a valve is also discussed.

A method of controlling an air intake flow in a rotary engine having primary and secondary inlet ports, including positioning the secondary inlet port rearwardly of the primary inlet port and forwardly of the exhaust port along a direction of a revolution of the rotor, and controlling air intake flows communicating between an air source and the primary and secondary inlet ports. During engine start-up, a primary valve is closed to prevent the intake air flow between the primary inlet port and the air source and a secondary valve is opened to allow the intake air flow between the secondary inlet port and the air source. A rotary engine defining different compression ratios through actuation of a valve is also discussed.