Rotary positive displacement machines based on trochoidal geometry, that comprise a helical rotor that undergoes planetary motion within a helical stator are described. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides structural and/or operational advantages in the rotary machine.

A pump housing for an eccentric screw pump, with a longitudinal axis and a hollow space constituted running axially between a drive-side opening and a pump-side opening, wherein the pump-side opening is enclosed by a main housing body and a lid fastened removably thereto, wherein the main housing body includes a ring segment-shaped axial guiding surface lying opposite the lid.

A hermetic compressor may include a cylinder having an elliptical inner circumferential surface; a roller eccentric from the inner circumferential surface; and at least one vane withdrawn towards the inner circumferential surface when the roller is rotated to divide a compression chamber. On the basis of a contact point where the inner circumferential surface and an outer circumferential surface are closest, a first center line passes through a center of the cylinder, an ellipse positioned at a first side of the first center line and forming the inner circumferential surface is a first ellipse, a center point of the first ellipse is a first center point, an ellipse positioned at a second side of the first center line and forming the inner circumferential surface is a second ellipse, a center point of the second ellipse is a second center point, and the first center point and the second center point are spaced apart from the center.

A compressor includes a rotary shaft, a rotating body, a fixed body, a vane, and a compression chamber. The vane has a vane end that contacts the surface of fixed body. The fixed body surface includes two curved surfaces. The curved surface includes a convex surface and a concave surface. The convex surface has a convex surface inner end and a convex surface outer end. The curvature of the convex surface inner end is greater than the curvature of the convex surface outer end. The concave surface has a concave surface inner end and a concave surface outer end. The curvature of the concave surface inner end is greater than the curvature of the concave surface outer end.

A vane rotary compressor includes: a cylinder forming a compression space having an inlet port and an outlet port, a roller having an outer circumferential surface of one side thereof almost coming into contact with an inner circumferential surface of the cylinder to form a contact point, and a plurality of vanes slidably inserted into the roller to protrude toward the inner circumferential surface of the cylinder so as to divide the compression space into a plurality of compression chambers, wherein ion at least one of the outer circumferential surface of the roller and the inner circumferential surface of the cylinder is provided a surface contact portion between the outer circumferential surface of the cylinder and the inner circumferential surface of the roller is constantly maintained in a preset section including the contact point in a circumferential direction.

A rotary engine having an insert in a peripheral wall of the stator body, the insert being made of a material having a greater heat resistance than that of the peripheral wall, having a subchamber defined therein and having an inner surface, the subchamber communicating with the cavity through at least one opening defined in the inner surface and having a shape forming a reduced cross-section adjacent the opening, a pilot fuel injector having a tip received in the subchamber, an ignition element having a tip received in the subchamber, and a main fuel injector extending through the stator body and having a tip communicating with the cavity at a location spaced apart from the insert. The subchamber has a volume corresponding to from 5% to 25% of a sum of the minimum volume and the volume of the subchamber. A method of injecting heavy fuel into a Wankel engine is also discussed.

Rotary positive displacement machines based on trochoidal geometry, that comprise a helical rotor that undergoes planetary motion within a helical stator are described. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides structural and/or operational advantages in the rotary machine.

Sealing in rotary positive displacement machines based on trochoidal geometry that comprise a helical rotor that undergoes planetary motion within a helical stator is described. Seals can be mounted on the rotor, the stator, or both. The rotor can have a hypotrochoidal cross-section, with the corresponding stator cavity profile being the outer envelope of the rotor as it undergoes planetary motion, or the stator cavity can have an epitrochoidal cross-section with the corresponding rotor profile being the inner envelope of the trochoid as it undergoes planetary motion. In some embodiments, the geometry is offset in a manner that provides advantages with respect to sealing in the rotary machine. In multi-stage embodiments, the rotor-stator geometry remains substantially constant or varies along the axis of the rotary machine.

A rotary engine having an outer body having an internal cavity with a peripheral wall having an insert opening defined therethrough in communication with the internal cavity, and a plurality of coolant passages defined through the peripheral wall in proximity of the insert opening, a rotor body rotatable within the internal cavity, and an insert removably received in the insert opening of the peripheral wall, the insert having a subchamber defined therein communicating with the internal cavity, with a minimum width of the insert opening being at least 0.75 inches. An outer body for a rotary engine and a method of inspecting in an internal cavity in an outer body of a rotary engine are also discussed; also, a rotary engine including a fuel injector having a tip received in the injector hole of the peripheral wall without protruding in the insert opening.

A compound engine system includes a rotary engine with rotating chambers, a compressor section in successive communication with the rotating chambers, and a turbine section in successive communication with the rotating chambers. The turbine section has an output shaft. The output shaft and the engine shaft are drivingly engaged to each other and wherein the turbine section has a power output corresponding to from 20% to 35% of a total power output of the compound engine system. A method of compounding power in a compound engine system is also discussed.