Abstract: Embodiments of a combination piston and piston ring to reduce the volume of a crevice defined between the circumferential wall of a cylinder and a portion of the outer wall of a piston within the cylinder, the portion extending down from the top of the piston. The combination piston and piston ring is configured such that pressurized fluid within the cylinder reliably urges a radial face of the piston ring to sealingly engage the circumferential wall of the cylinder, even as the piston reciprocates within the cylinder.

Abstract: Various embodiments describe modifications to X-engines, which would utilize a dedicated chamber to implement bottoming Rankine cycle as well as additional improvements in sealing and combustion efficiency—all contributing to high efficiency. Improvements in sealing include a face seal having multiple surfaces.

Abstract: A method of operating an internal combustion engine having a housing, a piston mounted in the housing for complex motion about a plurality of axes and coupled to a shaft, and wherein occur phases of compression, combustion, and expansion in the housing, and wherein, in the compression phase, air introduced through an intake port into the housing is compressed by reducing volume of a compression chamber in the housing from an initial volume to a second volume that is less than the initial volume, and in the expansion phase, byproducts of combustion expand from the second volume to a third volume that is greater than the initial volume.

Abstract: A rotary engine includes an intake port, an exhaust port, a rotor having an intake channel and/or an exhaust channel, and a rotor shaft coupled to the rotor. The rotor shaft has an inflow channel in communication with the intake channel and/or an outlet channel in communication with the exhaust channel. The rotary engine includes a housing having a working chamber formed between the housing and the rotor, the working chamber configured to handle, in succession, an intake phase, a compression phase, a combustion phase, an expansion phase, and an exhaust phase. The inflow channel cyclically communicates with the intake port and forms a passage between the intake port and the working chamber through the rotor shaft and the intake channel. The outlet channel cyclically communicates with the exhaust port and forms a passage between the exhaust port and the working chamber through the rotor shaft and the exhaust channel.

Abstract: Engines and methods execute a high efficiency hybrid cycle, which is implemented in a volume within an engine. The cycle includes isochoric heat addition and over-expansion of the volume within the engine, wherein the volume is reduced in a compression portion of the cycle from a first quantity to a second quantity, the volume is held substantially constant at the second quantity during a heat addition portion of the cycle, and the volume is increased in an expansion portion of the cycle to a third quantity, the third quantity being larger than the first quantity.

Abstract: An internal combustion rotary engine includes an air passage configured to allow cool air to flow through the rotor as the rotor moves relative to the housing within the engine. Some embodiments include a removable fuel cartridge.

Abstract: A rotary engine includes a housing having a working cavity, a shaft, the shaft having an eccentric portion, a rotor having a first axial face, and a second axial face opposite the first axial face, the rotor disposed on the eccentric portion and within the working cavity, the rotor comprising a first cam on the first axial face, the first came having an eccentricity corresponding to the eccentricity of the eccentric portion of the shaft, and a cover integral with, or fixedly attached to, the housing, the cover comprising a plurality or rollers, each roller engaged with the cam, wherein the cam guides the rotation of the rotor as the rotor rotates within the working cavity and orbits around the shaft.

Abstract: An internal combustion engine includes in one aspect a source of a pressurized working medium and an expander. The expander has a housing and a piston, movably mounted within and with respect to the housing, to perform one of rotation and reciprocation, each complete rotation or reciprocation defining at least a part of a cycle of the engine. The expander also includes a septum, mounted within the housing and movable with respect to the housing and the piston so as to define in conjunction therewith, over first and second angular ranges of the cycle, a working chamber that is isolated from an intake port and an exhaust port. Combustion occurs at least over the first angular range of the cycle to provide heat to the working medium and so as to increase its pressure.

Abstract: An internal combustion rotary engine includes an air passage configured to allow cool air to flow through the rotor as the rotor moves relative to the housing within the engine. Some embodiments include a removable fuel cartridge.

Abstract: A method of operating an internal combustion engine having a housing with a recess, and a piston rotatably mounted in the housing, wherein the housing and the piston form, over the course of shaft rotation, initial, second and third volumes in differing amounts for the phases of compression, combustion and expansion, in a manner that is smooth and continuous, which method includes (a) compressing air into a chamber formed by the recess and the piston, (b) introducing fuel into the chamber of compressed air, and (c) igniting the mixture of compressed air and fuel.

Abstract: Engines and methods execute a high efficiency hybrid cycle, which is implemented in a volume within an engine. The cycle includes isochoric heat addition and over-expansion of the volume within the engine, wherein the volume is reduced in a compression portion of the cycle from a first quantity to a second quantity, the volume is held substantially constant at the second quantity during a heat addition portion of the cycle, and the volume is increased in an expansion portion of the cycle to a third quantity, the third quantity being larger than the first quantity.

Abstract: A seal assembly includes first and second seal elements configured to lie adjacent to one another with a lower portion of each one disposed in a groove and an upper portion of each one projecting above the groove. The groove has a length disposed transverse to the direction of relative motion of a housing and a moving member and is located in the housing. The seal elements are further configured so that a contact surface of the upper portion of each seal element abuts the moving member and configured to allow independent movement of each seal element relative to each other in a direction transverse to the groove length. The seal elements are shaped to define a lubrication channel therebetween that is configured to allow the passage of a lubricant therein so as to lubricate motion of the seal elements relative to each other and relative to the moving member.

Abstract: An internal combustion engine includes in one aspect a source of a pressurized working medium and an expander. The expander has a housing and a piston, movably mounted within and with respect to the housing, to perform one of rotation and reciprocation, each complete rotation or reciprocation defining at least a part of a cycle of the engine. The expander also includes a septum, mounted within the housing and movable with respect to the housing and the piston so as to define in conjunction therewith, over first and second angular ranges of the cycle, a working chamber that is isolated from an intake port and an exhaust port. Combustion occurs at least over the first angular range of the cycle to provide heat to the working medium and so as to increase its pressure.

Abstract: Engines and methods execute a high efficiency hybrid cycle, which is implemented in a volume within an engine. The cycle includes isochoric heat addition and over-expansion of the volume within the engine, wherein the volume is reduced in a compression portion of the cycle from a first quantity to a second quantity, the volume is held substantially constant at the second quantity during a heat addition portion of the cycle, and the volume is increased in an expansion portion of the cycle to a third quantity, the third quantity being larger than the first quantity.

Abstract: An improved internal combustion engine of the four-stroke variable volume type operates by refraining from introducing substantial fuel into the working medium during the compression stroke until substantially maximum pressure of the working medium has been reached and utilizing at least one of the following processes: (a) causing combustion of fuel under substantially constant volume conditions; and (b) causing the power stroke to provide a larger volume to combustion products than the compression stroke provides to the working medium. Related methods are also provided.

Abstract: An internal combustion rotary engine includes an air passage configured to allow cool air to flow through the rotor as the rotor moves relative to the housing within the engine. Some embodiments include a removable fuel cartridge.

Abstract: A seal assembly includes first and second seal elements configured to lie adjacent to one another with a lower portion of each one disposed in a groove and an upper portion of each one projecting above the groove. The groove has a length disposed transverse to the direction of relative motion of a housing and a moving member and is located in the housing. The seal elements are further configured so that a contact surface of the upper portion of each seal element abuts the moving member and configured to allow independent movement of each seal element relative to each other in a direction transverse to the groove length. The seal elements are shaped to define a lubrication channel therebetween that is configured to allow the passage of a lubricant therein so as to lubricate motion of the seal elements relative to each other and relative to the moving member.

Abstract: A rotary engine has a cycloid rotor and a sealing grid including a face seal that rotates with the rotor, and including other seals that do not rotate with the rotor. As the rotor rotates within a housing, the rotor, housing and seal grid form at least one working chamber between them, the chamber undergoing a change from initial volume V1 to V2, which is less than V1, thus compressing a working medium, and subsequently expanding to volume V3, which may be larger than V1, such that the chamber volume is a smooth and continuous function of rotor's rotational angle.

Abstract: An improved internal combustion engine of the four-stroke variable volume type operates by refraining from introducing substantial fuel into the working medium during the compression stroke until substantially maximum pressure of the working medium has been reached and utilizing at least one of the following processes: (a) causing combustion of fuel under substantially constant volume conditions; and (b) causing the power stroke to provide a larger volume to combustion products than the compression stroke provides to the working medium. Related methods are also provided.

Abstract: An internal combustion engine includes in one aspect a source of a pressurized working medium and an expander. The expander has a housing and a piston, movably mounted within and with respect to the housing, to perform one of rotation and reciprocation, each complete rotation or reciprocation defining at least a part of a cycle of the engine. The expander also includes a septum, mounted within the housing and movable with respect to the housing and the piston so as to define in conjunction therewith, over first and second angular ranges of the cycle, a working chamber that is isolated from an intake port and an exhaust port. Combustion occurs at least over the first angular range of the cycle to provide heat to the working medium and so as to increase its pressure.