Low-noise-level internal combustion engine

摘要

A reciprocating piston internal combustion engine comprises an integrally formed or cast engine block having an upper half of main bearings for receiving the journal of a crankshaft, a bearing support frame secured to the bottom portion of the engine block and having a lower half of the main bearings, and a sound-insulating cover secured to the outer surface of the engine block to cover the lower part of the engine block, so that the engine noise and vibration can be effectively decreased.