A thermal choke, includes (1) a body, comprising a heat conductive material, (2) an electric heater, on or in the body, (3) a temperature sensor, on or in the body, and (4) a fin, in a channel surrounded by the body. The thermal choke is configured to fit between a throttle assembly and a cylinder of a spark ignition engine.

A thermal choke, includes (1) a body, comprising a heat conductive material, (2) an electric heater, on or in the body, (3) a temperature sensor, on or in the body, and (4) a fin, in a channel surrounded by the body. The thermal choke is configured to fit between a throttle assembly and a cylinder of a spark ignition engine.

An intake structure of the present invention is applied to a multi-cylinder engine including an electrically controlled throttle integrally including a throttle valve configured to adjust an amount of air to be supplied to the engine and an electronic control unit configured to control the throttle valve. The engine intake structure includes: an air cleaner configured to purify the air; and an intake manifold configured to distribute the air purified by the air cleaner to an intake port of each cylinder of the multi-cylinder engine. The electrically controlled throttle is attached to the intake manifold such that the electronic control unit is separated outward in a radial direction of an engine rotation shaft.

One embodiment of the invention relates to an internal combustion engine including an engine block having a first cylinder and a second cylinder, a crankshaft configured to rotate about a crankshaft axis, a flywheel coupled to the crankshaft, a throttle body, an air filter assembly, a first electric fan coupled to a first duct, and a second electric fan coupled to a second duct. The first duct is configured to direct cooling air directly over the first cylinder. The second duct is configured to direct cooling air directly over the second cylinder. The first cylinder is at least partially within the first duct. The second cylinder is at least partially within the second duct.

One embodiment of the invention relates to an internal combustion engine including an engine block having a first cylinder and a second cylinder, a crankshaft configured to rotate about a crankshaft axis, a flywheel coupled to the crankshaft, a throttle body, an air filter assembly, a first electric fan coupled to a first duct, and a second electric fan coupled to a second duct. The first duct is configured to direct cooling air directly over the first cylinder. The second duct is configured to direct cooling air directly over the second cylinder. The first cylinder is at least partially within the first duct. The second cylinder is at least partially within the second duct.

A split-cycle engine includes: a first cylinder housing a first piston, wherein the first piston performs an intake stroke and a compression stroke, but does not perform an exhaust stroke; a second cylinder housing a second piston, wherein the second piston performs an expansion stroke and an exhaust stroke, but does not perform an intake stroke; and a valve chamber housing a valve, the valve comprising an internal chamber that selectively fluidly couples to the first and second cylinders, wherein the valve and internal chamber move within the valve chamber and relative to the first and second cylinders.

A split-cycle engine includes: a first cylinder housing a first piston, wherein the first piston performs an intake stroke and a compression stroke, but does not perform an exhaust stroke; a second cylinder housing a second piston, wherein the second piston performs an expansion stroke and an exhaust stroke, but does not perform an intake stroke; and a valve chamber housing a valve, the valve comprising an internal chamber that selectively fluidly couples to the first and second cylinders, wherein the valve and internal chamber move within the valve chamber and relative to the first and second cylinders.

An engine assembly is provided that includes an engine having a crankshaft that is caused to rotate response to a firing of the engine, a backplate affixed to the engine and comprising one or more air flow passages formed therethrough, and an engine cooling fan operatively coupled to the crankshaft so as to be rotated by the crankshaft, the engine cooling fan coupled to the crankshaft on a side of the backplate opposite the engine. The engine assembly also includes a fan cover mounted over the engine cooling fan and secured to the backplate, the fan cover including an opening through which an air flow is provided to the engine cooling. The backplate and the fan cover collectively form an air guide that directs a flow of cooling air generated by the engine cooling fan through the one or more air flow passages of the backplate and to the engine.

A heat management system for air-cooled engines suitable to power yard care equipment or vehicles. The system may generally comprise an engine, a blower configured to blow ambient cooling air across the engine, and an exhaust system comprising an exhaust header and a muffler. The exhaust header has an inlet end which receives heated exhaust gas from the engine and an outlet end fluidly coupled to the muffler. An air control baffle is configured to redirect a portion of the cooling air from the blower towards the exhaust header and the muffler to enhance cooling the exhaust system. The system may further include an outermost protective shield exposed to equipment operators and an inner heat barrier or shield located between the muffler and protective shield. The system is designed to ameliorate both radiative and convective sources of heat transfer to maintain the protective shield at temperatures below established industry standards.

A heat management system for air-cooled engines suitable to power yard care equipment or vehicles. The system may generally comprise an engine, a blower configured to blow ambient cooling air across the engine, and an exhaust system comprising an exhaust header and a muffler. The exhaust header has an inlet end which receives heated exhaust gas from the engine and an outlet end fluidly coupled to the muffler. An air control baffle is configured to redirect a portion of the cooling air from the blower towards the exhaust header and the muffler to enhance cooling the exhaust system. The system may further include an outermost protective shield exposed to equipment operators and an inner heat barrier or shield located between the muffler and protective shield. The system is designed to ameliorate both radiative and convective sources of heat transfer to maintain the protective shield at temperatures below established industry standards.