An outboard motor has a vertical-shaft vee engine unit provided with a crankshaft arranged approximately vertically and left and right cylinder units aligned to be open backward in a V shape as seen in a plan view. A surge tank and an air intake system unit provided with an intake pipe to connect the surge tank to intake ports of the left and right cylinder heads are arranged in a center of a width direction of a rear side of the engine unit. In addition, an electronic control unit is arranged in an approximate center of a height direction in the right side of the air intake system unit. Furthermore, a high-pressure fuel filter is arranged in an approximate center of a height direction in the left side of the air intake system unit. Moreover, a vapor separator embedded with a high-pressure fuel pump is arranged under the high-pressure fuel filter.

An intake manifold is provided that controls swirl on entry to a combustion chamber. Each intake manifold includes a fin or rib portion positioned to reduce or eliminate swirl induced by the configuration of the intake manifold, particularly when used in a large engine having a left bank and a right bank of combustion chambers. By controlling swirl induced by the intake manifold, swirl consistency is improved between engine cylinders and between the left bank and the right bank, improving the consistency of power output and reducing emissions, particularly particulate emissions, also called smoke.

An intake manifold is provided that controls swirl on entry to a combustion chamber. Each intake manifold includes a fin or rib portion positioned to reduce or eliminate swirl induced by the configuration of the intake manifold, particularly when used in a large engine having a left bank and a right bank of combustion chambers. By controlling swirl induced by the intake manifold, swirl consistency is improved between engine cylinders and between the left bank and the right bank, improving the consistency of power output and reducing emissions, particularly particulate emissions, also called smoke.

An intake manifold is provided that controls swirl on entry to a combustion chamber. Each intake manifold includes a fin or rib portion positioned to reduce or eliminate swirl induced by the configuration of the intake manifold, particularly when used in a large engine having a left bank and a right bank of combustion chambers. By controlling swirl induced by the intake manifold, charge motion consistency is improved between engine cylinders and between the left bank and the right bank, thereby improving the consistency of combustion and power output, improving efficiency and reducing emissions (e.g., decreased particulate emissions (also described as smoke), hydrocarbon emissions, and NOx emissions), and further including an improved knock margin, improved fuel economy, wider rich and lean limits, etc.

An intake manifold is provided that controls swirl on entry to a combustion chamber. Each intake manifold includes a fin or rib portion positioned to reduce or eliminate swirl induced by the configuration of the intake manifold, particularly when used in a large engine having a left bank and a right bank of combustion chambers. By controlling swirl induced by the intake manifold, charge motion consistency is improved between engine cylinders and between the left bank and the right bank, thereby improving the consistency of combustion and power output, improving efficiency and reducing emissions (e.g., decreased particulate emissions (also described as smoke), hydrocarbon emissions, and NOx emissions), and further including an improved knock margin, improved fuel economy, wider rich and lean limits, etc.

An induction system for a supercharged internal V-type combustion engine includes a monolithic continuous unitary casting housing a supercharger with a rotor and gear assembly operative to discharge pressurized air to a common bounding receiving plenum, through a first slidably-removable intercooler providing a first cooling, and then to a pair of second side intercoolers providing a second cooling within the bounded plenum and in fluid communication therewith. First and second intercoolers are secured within the monolithic housing. The monolithic housing provides a robust and stable housing of light weight and allows an exterior air cooling as well. Side walls of the supercharger are separate from and are spaced from air intake runners of a cylinder block. Air in the plenum is additionally cooled by convective surface cooling while being guided in an appropriate direction. The intercoolers are plumbed in parallel allowing for enhanced temperature management of the air flow in combination with the convective cooling. The monolithic housing includes rib elements for sound attenuation and strength while minimizing weight. This arrangement allows for enhanced cooling, and simplifies manufacture and service.

An induction system for a supercharged internal V-type combustion engine includes a monolithic continuous unitary casting housing a supercharger with a rotor and gear assembly operative to discharge pressurized air to a common bounding receiving plenum, through a first slidably-removable intercooler providing a first cooling, and then to a pair of second side intercoolers providing a second cooling within the bounded plenum and in fluid communication therewith. First and second intercoolers are secured within the monolithic housing. The monolithic housing provides a robust and stable housing of light weight and allows an exterior air cooling as well. Side walls of the supercharger are separate from and are spaced from air intake runners of a cylinder block. Air in the plenum is additionally cooled by convective surface cooling while being guided in an appropriate direction. The intercoolers are plumbed in parallel allowing for enhanced temperature management of the air flow in combination with the convective cooling. The monolithic housing includes rib elements for sound attenuation and strength while minimizing weight. This arrangement allows for enhanced cooling, and simplifies manufacture and service.

A thermal fuel delivery system includes an insertion assembly and a fuel device. The insertion assembly includes a housing defining a cavity for housing the fuel device. The housing is disposed above and coupled to a pair of frame members via a plurality of connecting members. The frame members extend laterally away from the housing. The insertion assembly further includes an intake manifold coupled to the housing via a tube. A plurality of runner tubes extend laterally away from the intake manifold and pass through the frame members at an inner portion of the frame members and terminate at an outer portion of the frame members.

A thermal fuel delivery system includes an insertion assembly and a fuel device. The insertion assembly includes a housing defining a cavity for housing the fuel device. The housing is disposed above and coupled to a pair of frame members via a plurality of connecting members. The frame members extend laterally away from the housing. The insertion assembly further includes an intake manifold coupled to the housing via a tube. A plurality of runner tubes extend laterally away from the intake manifold and pass through the frame members at an inner portion of the frame members and terminate at an outer portion of the frame members.

An intake manifold includes a surge tank and a plurality of inlet pipes extending from the surge tank. Of the inlet pipes, proximal portions of an adjacent pair of inlet pipes are integrated, for example, by being connected with a plate-like connecting portion. The proximal portions of the two adjacent inlet pipes are integrated with a side wall of the surge tank by a reinforcing rib. The reinforcing rib extends, for example, from the connecting portion to the side wall of the surge tank. The intake manifold may be formed by a lower half body and an upper half body, which are welded to each other by using welding margins provided in the half bodies. In this case, it is preferable that parts of each welding margin that are located to correspond to the proximal portions of the inlet pipes be wider than the remainder of the same welding margin.