A rotary engine where the rotor cavity has a peripheral inner surface having a peritrochoid configuration defined by a first eccentricity and the rotor has a peripheral outer surface having a peritrochoid inner envelope configuration defined by a second eccentricity larger than the first eccentricity. Also, a rotary engine where the rotor cavity has a peripheral inner surface having a peritrochoid configuration defined by an eccentricity, and a rotor with a peripheral outer surface between adjacent ones of the apex portions being inwardly offset from a peritrochoid inner envelope configuration defined by the eccentricity. The engine may have an expansion ratio with a value of at most 8. The rotary engine may be part of a compound engine system.

A control device prevents damage due to backward rotation of a rotary engine and prevents misjudgment of backward rotation of the rotary engine. The control device for a rotary engine includes a motor mechanically connected to the shaft of the rotary engine, a controller (a motor ECU) that performs energization control of the motor to start the rotary engine by driving the motor, and a sensor (such as a motor rotation sensor). When starting the rotary engine, the controller stops energization to the motor based on an electric signal from the sensor when the shaft of the rotary engine rotates backward a predetermined angle or more, and then the shaft of the rotary engine continues to rotate backward for a predetermined time.

Closing timing of an intake port is changed without using a variable valve timing mechanism. An electric vehicle includes an engine for electricity generation in which closing timing of an intake port maximizes intake air charging efficiency in a specific revolution speed region, a sensor which outputs a signal related to a revolution speed of the engine, a controller which drives the engine at a revolution speed based on the signal of the sensor, a requested electricity generation amount being satisfied at the revolution speed, and a motor which applies a positive or negative torque to the engine. When the engine is driven in a revolution speed region other than the specific revolution speed region, the controller uses the motor to apply a positive or a negative torque to the engine in an intake stroke to change the closing timing of the intake port to increase intake air charging efficiency.

Aircraft power plants including combustion engines, and associated methods for recuperating waste heat from such aircraft power plants are described. A method includes transferring the heat rejected by the internal combustion engine to supercritical CO.sub.2 (sCO.sub.2) used as a working fluid in a heat engine. The heat engine converts at least some the heat transferred to the sCO.sub.2 to mechanical energy to perform useful work onboard the aircraft.

A rotary internal combustion engine has: a rotor; a housing circumscribing a rotor cavity, the rotor received within the rotor cavity, the housing having a peripheral wall and a side housing assembly secured to the peripheral wall, the side housing assembly having plates located at spaced apart ends of the peripheral wall, the plates defining seal running surfaces in sealing engagement with opposed end faces of the rotor, the plates made of silicon carbide.

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.

Aircraft power plants and associated methods are provided. A method for driving a load on an aircraft includes: transferring motive power from an internal combustion (IC) engine to the load; discharging a flow of first exhaust gas from the IC engine when transferring motive power from the IC engine to the load; receiving the flow of first exhaust gas from the IC engine into a combustor; mixing fuel with the first exhaust gas in the combustor and igniting the fuel to generate a flow of second exhaust gas; receiving the flow of second exhaust gas at a turbine and driving the turbine with the flow of second exhaust gas from the combustor; and transferring motive power from the turbine to the load.

The disclosure provides rotary machines that include, in one embodiment, a rotatable shaft defining a central axis A, the shaft having a first end and a second end. The shaft can have a first hub that defines a first gearbox disposed thereon with a plurality pivots. At least one contour also having pivots is connected to the first gearbox pivots by two linkages exterior to the first gearbox. The contour has a convex outer surface that cooperates with an inwardly facing curved surface of a housing to form a working volume. A gearbox mechanism including gears, crankshafts, bearings and connecting rods creates an oscillatory motion 2 times per revolution in the linkages such that the contour is forced to navigate about the arcuate cavity without contacting the cavity at a high rate of rotating speed.

A rotary internal combustion engine with a housing having a fluid passage defined therethrough opening into a portion of its inner surface engaging each peripheral or apex seal of the rotor. An injector has an inlet for fluid communication with a pressurized lubricant source and a selectively openable and closable outlet in fluid communication with the fluid passage for delivering the pressurized lubricant to each seal through the fluid passage. A housing for a Wankel engine and a method of lubricating peripheral seals of a rotor in an internal combustion engine are also discussed.

Pressure changing devices and methods of making and using the same are disclosed. One pressure changing device includes an elliptic cylinder and a piston that has an external surface with a trochoid cross-section. Another pressure changing device includes a piston and a rotating cylinder that has an internal surface with a trochoid cross-section. Another pressure changing device includes two fixed axes, one for rotation of one component and another for orbiting or oscillation of the other component. The devices and methods include stacked pressure changing devices with one or more common shafts. The pressure changing device may be easier and less expensive to manufacture and repair than prior pressure changing devices of the same or similar functionality, and can provide efficient gap sealing in a high-pressure expansion part of a compression or expansion cycle.