Patent ID: 8784086

Claim:
An engine comprising: a fluid inlet; a fluid outlet; a rotary valve downstream from the fluid inlet, the rotary valve including a drum defining a rotation axis and a circumference, a first channel-structure configured to conduct fluid from the fluid inlet, a length of the first channel-structure, along the circumference, varying with the displacement of the drum along the rotation axis, and a second channel-structure configured to conduct fluid from the fluid inlet, the second channel-structure being connected in parallel with the first channel-structure, the second channel-structure being located such that the rotation axis is between the second channel-structure and the first channel-structure; a first rotary piston including a first abutment, the first abutment being configured to be driven by fluid from the rotary valve, and a second abutment, the second abutment being configured to drive fluid to the fluid outlet; and a second rotary piston including a first abutment, the first abutment being configured to be driven by fluid from the rotary valve, and a second abutment, the second abutment being configured to drive fluid to the fluid outlet, and to drive the first abutment of the first rotary piston, wherein the second abutment of the first rotary piston is configured to drive the first abutment of the second rotary piston, wherein the rotary valve is configured to rotate synchronously with the first rotary piston.