A mobile emissions control system is provided for diesel engines operated on ocean-going ships at-berth. The emissions control system comprises two essential elements: an emissions capturing system and an emissions control system. The emissions control system may be mounted on a towable chassis or mounted on a barge, allowing it to be placed alongside ocean-going ships at-berth. The emission capturing system captures exhaust from a ship's diesel engine and conducts it into the emissions control system, which cleans the exhaust and then passes clean air into the atmosphere through an exhaust outlet.

An outboard motor is provided with an upper separator disposed on the lower side of an oil case for storing a lubricating oil of an engine, and an extension case which is separably connected on the lower side of the upper separator. The upper separator has a central exhaust passage through which exhaust gas flows, and a cooling water flow part through which cooling water flows on the outside of the central exhaust passage, the central exhaust passage and the cooling water flow part forming an integrated structure. The exhaust gas and the cooling water are caused to mix in the extension case.

A marine propulsion device includes an engine, an exhaust pipe to allow exhaust gas of the engine to pass through the exhaust pipe, and a cooling water supply passage to supply cooling water for the engine into the exhaust pipe toward a downstream side in a flow direction of the exhaust gas and cause the cooling water to flow circumferentially along an inner peripheral surface of the exhaust pipe.

A marine propulsion device includes an engine, an exhaust pipe to allow exhaust gas of the engine to pass through the exhaust pipe, and a cooling water supply passage to supply cooling water for the engine into the exhaust pipe toward a downstream side in a flow direction of the exhaust gas and cause the cooling water to flow circumferentially along an inner peripheral surface of the exhaust pipe.

A watercraft and a marine engine assembly for mounting to a watercraft are disclosed. The marine engine assembly includes an engine unit including: an engine unit housing being sealed such that water in which the engine unit housing is immersed is impeded from entering the engine unit housing; an engine in the housing; and an air intake assembly in the engine unit housing which forms a conduit between an exterior of the engine unit housing and the engine, the air intake assembly defining an inlet fluidly communicating with exterior air, the engine unit housing defining at least one aperture aligned with the inlet, the air intake assembly defining at least one outlet fluidly connected with the engine intake, the air intake assembly being sealed such that surrounding fluids within the engine unit housing are impeded from entering the air intake assembly; and a propulsion device operatively connected to the engine.

An outboard motor includes a first case accommodating an engine and an upper housing below the first case. At least a portion of an exhaust passage is in the upper housing and extends downward from the engine. A second case is below the upper housing. The second case includes a torpedo portion, an exhaust inlet, an exhaust outlet, and an exhaust chamber. The torpedo portion includes an internal space and a rear end. A propeller shaft is in the internal space of the torpedo portion. The rear end of the torpedo portion is forward of at least a portion of the exhaust passage as seen in a side view. The exhaust passage is connected to the exhaust inlet. The exhaust outlet communicates with the internal space of the torpedo section. The exhaust chamber communicates the exhaust inlet with the exhaust outlet.

An outboard motor includes a first exhaust passage connected to an exhaust port and extending downward from the exhaust port through a support frame on a lateral side of a cylinder head. A first case accommodates an engine. A second case accommodates a propeller shaft. A third case is between the first case and the second case in a vertical direction. An exhaust pipe is between the first case and the second case in the vertical direction. The exhaust pipe is connected to the first exhaust passage. At least a portion of the exhaust pipe is outside the third case as seen in a side view of the outboard motor. An exterior cover is between the first case and the second case in the vertical direction. The exterior cover covers the exhaust pipe.

An outboard motor includes a first exhaust passage connected to an exhaust port and extending downward from the exhaust port through a support frame on a lateral side of a cylinder head. A first case accommodates an engine. A second case accommodates a propeller shaft. A third case is between the first case and the second case in a vertical direction. An exhaust pipe is between the first case and the second case in the vertical direction. The exhaust pipe is connected to the first exhaust passage. At least a portion of the exhaust pipe is outside the third case as seen in a side view of the outboard motor. An exterior cover is between the first case and the second case in the vertical direction. The exterior cover covers the exhaust pipe.

A marine drive is configured to propel a marine vessel in a body of water. The marine drive has an engine; a primary exhaust conduit receiving exhaust gases from the engine and discharging the exhaust gases to a primary exhaust outlet discharging the exhaust gases to the body of water; an idle relief exhaust outlet discharging exhaust gases to atmosphere, above the body of water; a primary idle relief muffler receiving exhaust gases from the primary exhaust conduit; a secondary idle relief muffler receiving exhaust gases from the primary idle relief muffler; and a tertiary idle relief muffler configured to receive exhaust gases from the secondary idle relief muffler and discharges exhaust gases to atmosphere via the idle relief exhaust outlet.

A marine drive is configured to propel a marine vessel in a body of water. The marine drive has an engine; a primary exhaust conduit receiving exhaust gases from the engine and discharging the exhaust gases to a primary exhaust outlet discharging the exhaust gases to the body of water; an idle relief exhaust outlet discharging exhaust gases to atmosphere, above the body of water; a primary idle relief muffler receiving exhaust gases from the primary exhaust conduit; a secondary idle relief muffler receiving exhaust gases from the primary idle relief muffler; and a tertiary idle relief muffler configured to receive exhaust gases from the secondary idle relief muffler and discharges exhaust gases to atmosphere via the idle relief exhaust outlet.