A fluid-cooled manifold is configured to cool exhaust from an engine. The fluid-cooled manifold includes a plurality of exhaust runners. Each of the exhaust runners includes a runner body having an inlet end and an outlet end, an exhaust conduit extending through the runner body, and a coolant passage extending through the runner body. The fluid-cooled manifold also includes an exhaust collection manifold including a plurality of inlets. Each inlet of the exhaust collection manifold is coupled to the exhaust outlet opening of a respective one of the exhaust runners. The fluid-cooled manifold also includes a coolant feed pipe and a coolant exit pipe. The coolant feed pipe includes a plurality of outlets coupled to the coolant inlets of the exhaust runners. Likewise, the coolant exit pipe includes a plurality of inlets coupled to the coolant outlets of the exhaust runners.

A vortex generating exhaust component is installed in-line within a marine exhaust system downstream of the water can whereby a mixture of hot exhaust gas and entrained cooling water flows there through and vortex flow is enhanced by the component to increase cooling of exhaust gas by increasing the mixing of hot exhaust gas with entrained cooling water thereby resulting in enhanced exhaust gas cooling.

A cooling structure for an outboard motor comprises an oil case which has an oil chamber for storing lubricant oil for an engine. Said cooling structure further comprises: a main exhaust gas passage which guides exhaust gas to a lower side; a cooling water outbound path which guides cooling supply water taken from outside the outboard motor to an upper side, and cools the periphery of the main exhaust gas passage in the oil case by means of the cooling supply water; a cooling water inbound path which guides cooling discharge water that has cooled the engine to the lower side and cools the oil chamber by means of said cooling discharge water; and a mixed fluid passage which, on a side below the oil case, cools the exhaust gas by mixing the exhaust gas and the cooling discharge water.

A catalyst device includes a catalyst carrier serving as a heating element that generates heat when energized. The catalyst device includes a guide pipe that guides exhaust into the case. The catalyst device includes a connecting pipe that connects the guide pipe to the case. The case has an end that is an insulative portion and projects further upstream, in the direction in which exhaust flows, from an end surface of the catalyst carrier. A temperature difference inducing structure, which induces a state in which the connecting pipe is relatively lower in temperature than the end of the case, includes a heat shield, encompassing an outer circumferential surface of the connecting pipe and having an opening in part of a portion opposing the outer circumferential surface of the connecting pipe, and a stay fixing the outer circumferential surface of the connecting pipe to an internal combustion engine.

An applied-ignition internal combustion engine includes first and second combustion chambers, an exhaust-gas system with an exhaust-gas purification system is disposed at the first and second combustion chambers, and an exhaust-gas manifold. An exhaust gas from a combustion of a an air/fuel mixture firstly flows through the exhaust-gas manifold and subsequently flows through the exhaust-gas purification system. A first section of the exhaust-gas system from the first combustion chamber to the exhaust-gas purification system is cooled more than a second section of the exhaust-gas system from the second combustion chamber to the exhaust-gas purification system. The first combustion chamber is operated with a lean air/fuel mixture, the second combustion chamber is operated with a rich air/fuel mixture, and an overall exhaust-gas lambda value at an inlet into the exhaust-gas purification system is stoichiometric.

A fluid-cooled manifold is configured to cool exhaust from an engine. The fluid-cooled manifold includes a plurality of exhaust runners. Each of the exhaust runners includes a runner body having an inlet end and an outlet end, an exhaust conduit extending through the runner body, and a coolant passage extending through the runner body. The fluid-cooled manifold also includes an exhaust collection manifold including a plurality of inlets. Each inlet of the exhaust collection manifold is coupled to the exhaust outlet opening of a respective one of the exhaust runners. The fluid-cooled manifold also includes a coolant feed pipe and a coolant exit pipe. The coolant feed pipe includes a plurality of outlets coupled to the coolant inlets of the exhaust runners. Likewise, the coolant exit pipe includes a plurality of inlets coupled to the coolant outlets of the exhaust runners.

A cylinder head is disclosed herein to allow for temperature control of exhaust gases exiting from an associated exhaust manifold. The cylinder head includes a combustion section that defines a plurality of combustion chambers and an exhaust manifold coupled to the combustion section. The combustion section fluidly couples to exhaust inlets defined by the exhaust manifold. The exhaust manifold includes at least one exhaust passageway in fluid communication with the exhaust inlets and in fluid communication with an exhaust outlet to receive combustion gases from the combustion section and output the same via the exhaust outlet. The exhaust manifold further includes at least one coolant passageway that at least partially surrounds the at least one exhaust passageway to pass coolant therethrough in order to draw and reject heat from exhaust gases.

An exhaust gas purification structure of an outboard motor includes an exhaust gas pipe that has an exhaust gas passage through which exhaust gas of an engine can flow; and a catalyst that is provided in the exhaust gas passage and purifies the exhaust gas by allowing the exhaust gas to pass through the inside thereof. The exhaust gas pipe includes a coolant flow passage allowing a coolant that cools the exhaust gas to flow therethrough. An exhaust gas bypass passage allowing the exhaust gas to flow without passing through the catalyst is formed between the catalyst and an inner surface of the exhaust gas pipe forming the exhaust gas passage.

A system includes an engine defining a water jacket fluidly coupled to a heat exchanger. An exhaust manifold defines an exhaust manifold cooling passage. A pump is fluidly coupled to the water jacket, and to each of the heat exchanger and the exhaust manifold cooling passage. An engine cooling circuit includes the water jacket, the heat exchanger, and the pump. An exhaust cooling circuit is selectively fluidly coupled to the engine cooling circuit. The exhaust cooling circuit includes the water jacket, the exhaust manifold cooling passage, and the pump. A control valve includes an inlet fluidly coupled to a first portion of the water jacket. A first outlet is fluidly coupled to a second portion of the water jacket. A second outlet is fluidly coupled to the exhaust cooling circuit. The control valve is structured to selectively control flow of coolant fluid through the second outlet.

A system includes an engine defining a water jacket fluidly coupled to a heat exchanger. An exhaust manifold defines an exhaust manifold cooling passage. A pump is fluidly coupled to the water jacket, and to each of the heat exchanger and the exhaust manifold cooling passage. An engine cooling circuit includes the water jacket, the heat exchanger, and the pump. An exhaust cooling circuit is selectively fluidly coupled to the engine cooling circuit. The exhaust cooling circuit includes the water jacket, the exhaust manifold cooling passage, and the pump. A control valve includes an inlet fluidly coupled to a first portion of the water jacket. A first outlet is fluidly coupled to a second portion of the water jacket. A second outlet is fluidly coupled to the exhaust cooling circuit. The control valve is structured to selectively control flow of coolant fluid through the second outlet.