| 摘要 |
PROBLEM TO BE SOLVED: To aim at promotion of fuel evaporation so as to enhance fuel stability during a low load/low speed operation by interposing a switching valve for communicating a pressure introduction system to the atmosphere during a low load/low speed operation of an engine in the pressure introduction system for providing communication between a pressure regulator and an air suction system. SOLUTION: As well as forcibly feeding fuel by means of a high pressure fuel pump 30 to the bottom end of a fuel rail 29 to which the fuel injector 21 of an outboard motors is connected, any residual fuel is returned to a vapor separator tank 23 via a pressure regulator 31 from the top end of the fuel rail 29. This pressure regulator 31 is communicated with an intake air passage inside of a surge tank 12a via a pressure introduction system consisting of the pressure introduction tube 32 and the solenoid type switching valve 33 of a negative pressure chamber. And this solenoid type switching valve 33 is subjected to driving control by means of a controller 25 in which a way that the negative pressure chamber is released to the atmosphere when the engine 2 is in its low load/low speed operational state and the negative pressure chamber is in its state of communicating with the surge tank 12a in other operational state. |
