Air induction system for engine

An internal combustion engine for powering a marine propulsion device comprising an engine body and an air induction system, the engine body comprising a cylinder block defining a cylinder bore, a piston reciprocally mounted in the cylinder bore, and a cylinder head assembly closing an end of the cylinder bore to define a combustion chamber together with the cylinder bore and the piston, the air induction system arranged to introduce air into the combustion chamber, the induction system including a first intake conduit through which the air flows to the combustion chamber, a first plenum chamber unit being disposed upstream of the first intake conduit, a control mechanism arranged to control an amount of the air flowing through the first intake conduit, a second intake conduit through which the air flows to the combustion chamber, and a second plenum chamber unit being disposed upstream of the second intake conduit, the second intake conduit being coupled with the first intake conduit downstream of the control mechanism.

An internal combustion engine comprising an engine body, a moveable member moveable relative to the engine body, movement of the moveable member being transferred to a marine propulsion device, the engine body and the moveable member together at least partially defining a combustion chamber, an air induction system arranged to introduce air into the combustion chamber, the induction system including a primary intake conduit through which the air flows to the combustion chamber, a first voluminous unit disposed upstream of and communicating with the primary intake conduit, a throttle valve arranged to control an amount of the air flowing through the primary intake conduit, the throttle valve generally allowing the majority of the air to flow through the primary intake conduit at an engine speed above an idle speed, an auxiliary intake conduit through which air at the idle speed flows to the combustion chamber, and a second voluminous unit disposed upstream of the auxiliary intake conduit, the auxiliary intake conduit communicating with the primary intake conduit downstream of the throttle valve.

An internal combustion engine comprising an engine body, a moveable member moveable relative to the engine body, the engine body and the moveable member together defining a combustion chamber, an air induction system arranged to introduce air into the combustion chamber, the induction system including an intake conduit through which the air flows, a first member, and a second member together with the first member defining a plenum chamber disposed upstream the intake conduit, both the first and second members being mounted on the engine body, and the first and second members being coupled with one another to form a gap therebetween through which the air enters the plenum chamber.

An outboard motor comprising a drive unit, and a bracket assembly adapted to be mounted on an associated watercraft to support the drive unit, the drive unit including an internal combustion engine, the engine comprising an engine body, a moveable member moveable relative to the engine body, the engine body and the moveable member together defining a combustion chamber, an air induction system arranged to introduce air into the combustion chamber, the induction system including a first intake conduit through which the air flows to the combustion chamber, a first plenum chamber unit disposed upstream of the first intake conduit, a control mechanism configured to control an amount of the air flowing through the first intake conduit, a second intake conduit through which the air flows to the combustion chamber, and a second plenum chamber unit disposed upstream of the second intake conduit, the second intake conduit being coupled with the first intake conduit downstream of the control mechanism, and the second plenum chamber unit being disposed opposite to the bracket assembly relative to the engine body.

An internal combustion engine comprising an engine body, a moveable member moveable relative to the engine body, the engine body and the moveable member together at least partially defining a combustion chamber, an air induction system arranged to introduce air into the combustion chamber, the induction system including a primary intake conduit through which the air flows to the combustion chamber, a first voluminous unit disposed upstream of the primary intake conduit, a throttle valve arranged to control an amount of the air flowing through the primary intake conduit, the throttle valve generally allowing the majority of the air to flow through the primary intake conduit at an engine speed above an idle speed, an auxiliary intake conduit through which air at the idle speed flows to the combustion chamber, and a second voluminous unit disposed upstream of the auxiliary intake conduit, the second voluminous unit being only connected to a portion of the primary intake conduit located downstream of the throttle valve through the auxiliary intake conduit.