INTAKE SYSTEM IN V-TYPE 4-STROKE ENGINE FOR OUTBOARD ENGINE SYSTEM

摘要

An intake system in a V-type 4-stroke engine for anoutboard engine system is provided. A crankshaft of the engineis disposed vertically, and heads of left and right banks aredisposed to face rearwards. The engine is covered with anengine hood. In the intake system, an intake air inlet isprovided in an upper portion of a longitudinally flat intakeair dispensing box disposed between the left and right banksand a rear wall of the engine hood, and leads to an intakepassageway in a throttle body. The inside of the intake airdispensing box is divided by a partition wall into first andsecond dispensing chambers communicating with the intake airinlet and extending longitudinally. An on-off valve is mountedon the partition wall and is capable of bringing the first andsecond dispensing chambers into and out of communication witheach other. Intake ports are provided in the left and rightbanks to communicate with the first and second dispensingchambers, respectively. Thus, it is possible to provide anintake system for a V-type 4-stroke engine in an outboard enginesystem, in which the air-charging characteristic can be changedin accordance with the operation state of the engine, whileavoiding an increase in size of the engine hood.