An engine includes: an exhaust manifold 7 close to one of left and right side surfaces of an engine; a turbocharger 60 having an exhaust-side inlet connected to the exhaust manifold 7; and a rocker-arm-chamber-integrated intake manifold 8 being disposed on an upper surface of a cylinder head 5 and integrally including a rocker arm chamber 90 and an intake manifold 6. The intake manifold 8 has a wall 101 dividing the rocker arm chamber 90 close to the one of the left and right side surfaces of the engine 1 and the intake manifold 6 close to the other of the left and right side surfaces to isolate the rocker arm chamber 90 and the intake manifold 6 from each other. The rocker arm chamber 90 has, in its upper portion, a positive crankcase ventilation device 69 protruding therefrom and being configured to return blowby gas to an intake system. The positive crankcase ventilation device 69 has, in its side surface, a blowby-gas discharge port 67 connected with a gas conduit 68 through which blowby gas is delivered to an intake-side inlet of the turbocharger 60.

A saddle riding vehicle includes a body frame, an exhaust pipe, a muffler, and a catalyst. The body frame includes a main frame, a seat frame that extends rearward from the main frame and supports a seat for occupant, and a rear frame that extends from the main frame upward to a rear and is connected to the seat frame. The exhaust pipe extends rearward of the vehicle from an exhaust port of an engine. The muffler is connected to a rear end portion of the exhaust pipe. The catalyst is disposed in the muffler. An air cleaner box is disposed rearward of the engine. The catalyst disposed in the muffler is disposed in a space surrounded by the main frame, the seat frame, and the rear frame and overlaps with the air cleaner box as viewed in a side view of the vehicle.

A system includes a generator and an enclosure surrounding the generator, the generator having an air intake and an inside surface. The system also includes an air intake housing affixed to the inside surface of the enclosure and fluidly connected to the air intake, the air intake housing terminating in an air intake housing inner plate positioned at inner edge of the air intake housing. The air intake housing inner plate has a plurality of air intake holes. In addition, the system includes a damper, the damper abutting the air intake housing inner plate, the damper having a plurality of damper holes. The damper is adapted to slide along the air intake housing inner plate.

A cooling device includes a surrounding member, an air inlet, an air outlet, and a flow-path-formation mechanism. The surrounding member is configured to surround an engine. The air inlet is formed in the surrounding member. The air outlet is formed in the surrounding member and is to be coupled to an intake pipe of the engine. The flow-path-formation mechanism is configured to form a flow path that allows outside air to circulate to the air outlet from the air inlet when a temperature of the engine or a temperature inside the surrounding member is greater than or equal to a predetermined temperature.

A cover covering an engine and an intake duct for introducing fresh air outside an engine room into a combustion chamber of the engine are provided in the engine room. The cover includes a top face cover portion covering the engine from above, and a side face cover portion covering the engine from the lateral side. The intake duct is disposed so as to be continuous to a side edge of the side face cover portion such that the intake duct covers the engine from the lateral side together with the side face cover portion.

An engine includes: an exhaust manifold 7 close to one of left and right side surfaces of an engine; a turbocharger 60 having an exhaust-side inlet connected to the exhaust manifold 7; and a rocker-arm-chamber-integrated intake manifold 8 being disposed on an upper surface of a cylinder head 5 and integrally including a rocker arm chamber 90 and an intake manifold 6. The intake manifold 8 has a wall 101 dividing the rocker arm chamber 90 close to the one of the left and right side surfaces of the engine 1 and the intake manifold 6 close to the other of the left and right side surfaces to isolate the rocker arm chamber 90 and the intake manifold 6 from each other. The rocker arm chamber 90 has, in its upper portion, a positive crankcase ventilation device 69 protruding therefrom and being configured to return blowby gas to an intake system. The positive crankcase ventilation device 69 has, in its side surface, a blowby-gas discharge port 67 connected with a gas conduit 68 through which blowby gas is delivered to an intake-side inlet of the turbocharger 60.

An engine includes: an exhaust manifold 7 close to one of left and right side surfaces of an engine; a turbocharger 60 having an exhaust-side inlet connected to the exhaust manifold 7; and a rocker-arm-chamber-integrated intake manifold 8 being disposed on an upper surface of a cylinder head 5 and integrally including a rocker arm chamber 90 and an intake manifold 6. The intake manifold 8 has a wall 101 dividing the rocker arm chamber 90 close to the one of the left and right side surfaces of the engine 1 and the intake manifold 6 close to the other of the left and right side surfaces to isolate the rocker arm chamber 90 and the intake manifold 6 from each other. The rocker arm chamber 90 has, in its upper portion, a positive crankcase ventilation device 69 protruding therefrom and being configured to return blowby gas to an intake system. The positive crankcase ventilation device 69 has, in its side surface, a blowby-gas discharge port 67 connected with a gas conduit 68 through which blowby gas is delivered to an intake-side inlet of the turbocharger 60.

An air intake circuit for a heat engine is intended to be positioned between an air compression element and at least an upper portion of a hollow combustion chamber in a cylinder head of the engine. The air intake circuit includes the cylinder head, an air intake manifold, and at least one air intake duct. The circuit also includes at least one concave receptacle turned towards the outside of the engine, housed in a cavity of the cylinder head, and connected to a tubular element pushed into the at least one air intake duct.

A heat storage cover is provided in an engine room. The heat storage cover covers an engine from above and surrounds the periphery of an upper portion of the engine to internally store, through the medium of air, heat dissipated from the engine and block upward heat dissipation. The engine includes an air inlet for introducing, into a combustion chamber, high temperature air obtained by the heat storage cover blocking the upward heat dissipation.

An air intake system is provided that supplies charge air to multiple cylinders in an in-line configuration in an uniflow-scavenged, two-stroke opposed-piston engine. The engine is configured such that the intake ports of the cylinders are situated in one intake chamber within the engine block. The air intake chamber includes a feature to balance the mass of air that reaches the intake port of each cylinder in the engine.