PURPOSE: To cool electrical equipment efficiently by providing the appropriate number of cooling fins protrusively inside of an intake manifold lid member, and prevent a fitting bolt from slipping off by setting the distance between the bolt hole of an intake manifold and each cooling fin to be shorter than the whole length of the fitting bolt.
CONSTITUTION: An intake manifold 5 connected to an intake pipe part 4 formed at a crankcase 11 is covered with a lid member 6 so as to form an intake passage. Intake manifold members 52, 53 are fitted by passing a fitting bolt 54 through bolt holes 522, 532. Electrical equipment 8 for controlling an engine is disposed at the lid member 6. Intake air is supplied into a crank chamber 111 through a throttle valve 7 and the like. In this case, the appropriate number of fins 61 for cooling the electrical equipment 8 are protrusively provided inside of the lid member 6, and the distance (t) between the bolt hole part 532 of the first intake manifold member 53 and the tip of each fin 61 is set to be shorter than the whole length of the fitting bolt 54.
MIYATA SHOICHIRO
MOTOSE JIYUN
NAGAHORA OSAMU
