An intake manifold is connected to a cylinder head, and extends backward therefrom. An injector is attached to either the cylinder head or the intake manifold. At least one of the cylinder head and the intake manifold includes a curve pipe portion shaped to curve backward from a lateral surface of the cylinder head. An injector is attached to the cylinder head at either an outer lateral surface of the curve pipe portion in a right-and-left direction of an outboard motor or a position located forward of the curve pipe potion.

An air cooling device includes a first inlet surge tank, a first heat exchanger to cool air introduced from the first surge tank, a second inlet surge tank, a second heat exchanger to cool air introduced from the second surge tank, and an outlet surge tank. The outlet surge tank receives both of airs introduced from the first heat exchanger and the second heat exchanger and the airs flows from the outlet surge tank toward an internal combustion engine. The outlet surge tank includes a merging space and a fixing hole. The merging space is where the airs introduced from the first heat exchanger and the second heat exchanger merge with each other. A fastening member to fasten the outlet surge tank passes through the fixing hole from an outer surface of the outlet surge tank away from the merging space toward the internal combustion engine.

An intake device for an internal combustion engine configures a flow passage for intake air that is drawn into combustion chambers. The intake device includes an intake manifold configuring multiple runners that respectively distribute intake air to multiple cylinders, a surge tank including a cavity that is connected to the runners and defines a convergence portion, a throttle body incorporating a throttle valve, and a connection pipe connecting the surge tank and the throttle body and configuring a curved flow passage extending between the throttle body and the surge tank. The connection pipe includes a partition plate that divides the curved flow passage into a circumferentially inner flow passage and a circumferentially outer flow passage.

An airflow modifier device for reducing air velocity fluctuations in a multi-throttle internal combustion engine. The device includes: first and second air input ports for receiving respective first and second airflows outputted from respective first and second throttles; first and second air output ports for providing air from one or both of the airflows to manifold input ports of a pair of intake air manifolds; and first and second passageways respectively connecting the first air input port with the first air output port and the second air input port with the second air output port. The airflow modifier device further includes a central passageway interconnecting the first and second passageways so that air entering the first and second air input ports can move between the first and second passageways and can thereby reduce air flow velocity fluctuations at flow sensors located in the airflows upstream of the airflow modifier device.

An airflow modifier device for reducing air velocity fluctuations in a multi-throttle internal combustion engine. The device includes: first and second air input ports for receiving respective first and second airflows outputted from respective first and second throttles; first and second air output ports for providing air from one or both of the airflows to manifold input ports of a pair of intake air manifolds; and first and second passageways respectively connecting the first air input port with the first air output port and the second air input port with the second air output port. The airflow modifier device further includes a central passageway interconnecting the first and second passageways so that air entering the first and second air input ports can move between the first and second passageways and can thereby reduce air flow velocity fluctuations at flow sensors located in the airflows upstream of the airflow modifier device.

A first throttle body and a second throttle body include valve rotation devices that independently drive respective throttle valves. The first throttle body and the second throttle body are arranged such that the respective valve rotation devices have states rotated around respective bore central axes to cause respective throttle valve rotation shafts to have angles with respect to straight lines parallel to a crankshaft in an engine top view.

A first throttle body and a second throttle body include valve rotation devices that independently drive respective throttle valves. The first throttle body and the second throttle body are arranged such that the respective valve rotation devices have states rotated around respective bore central axes to cause respective throttle valve rotation shafts to have angles with respect to straight lines parallel to a crankshaft in an engine top view.

The present disclosure provides a charge air cooler system having a manifold charge air cooler, a first charge air cooler and a second charge air cooler wherein each charge air cooler are in fluid communication with each other. The manifold charge air cooler is within a plenum and defines a first chamber and a second chamber within the plenum. The manifold charge air cooler is configured to cool of unsteady flow between the first and second chambers. The first charge air cooler may be configured to cool a first ambient air flow and may be in fluid communication with the first chamber. The second charge air cooler may be configured to cool a second ambient air flow wherein the second charge air cooler is in fluid communication with the second chamber.

The present disclosure provides a charge air cooler system having a manifold charge air cooler, a first charge air cooler and a second charge air cooler wherein each charge air cooler are in fluid communication with each other. The manifold charge air cooler is within a plenum and defines a first chamber and a second chamber within the plenum. The manifold charge air cooler is configured to cool of unsteady flow between the first and second chambers. The first charge air cooler may be configured to cool a first ambient air flow and may be in fluid communication with the first chamber. The second charge air cooler may be configured to cool a second ambient air flow wherein the second charge air cooler is in fluid communication with the second chamber.

An intake manifold 10 includes: a blowby gas introduction port 16g that is configured to introduce blowby gas into a PCV chamber 15; a blowby gas exhaust port 16f that is configured to discharge the blowby gas from the PCV chamber 15 into a surge tank 11; and a drain hole 17c that is configured to discharge water contained in the blowby gas, from the PCV chamber 15 into the surge tank 11. A bottom wall 17d of the surge tank 11 includes protruding parts 17e, 17f that protrude upward, the blowby gas exhaust port 16f is located upstream of the most upstream side protruding part 17e located on the most upstream side, and the drain hole 17c is located downstream of the most upstream side protruding part.