An electrical unit mounting structure is provided to dispose an electrical unit
that emits a large amount of heat such that cooling performance is ensured. In
one embodiment, an injector drive unit (IDU) 7 is mounted to an upper wall
of a collector 6, which is disposed on an uppermost part of the engine 1
between the banks. The injector drive unit 7 is equipped with the cooling
fins 7b on the lower surface thereof and is cooled with good efficiency
by cooling air flowing in the longitudinal direction between the engine cover 10
and the collector 6. The electrical unit mounting structure can be used
in a variety of engine arrangements such as a longitudinally arranged V-type engine,
a transversely arranged V-type engine, a longitudinally arranged inline engine,
or a transversely arranged inline engine.
