Patent ID: 6253727
Filing Date: 2001-07-03
Classification: F01L,F01M,F02B

Abstract:
An engine having an oil passage structure for returning oil comprising:a plurality of cylinder heads;a plurality of cylinder blocks, each of said plurality of cylinder blocks including a plurality of cylinder bores having substantially horizontal axes;a plurality of pistons, each of said plurality of pistons being fitted in a freely slidable manner into said plurality of cylinder bores, respectively;a plurality of combustion chambers corresponding to each of said plurality of cylinder bores are formed between said plurality of pistons and said plurality of cylinder heads, respectively;cam shafts interlocking with and coupled to a plurality of intake valves and a plurality of exhaust valves controlling intake of air to and exhaust emissions from the combustion chambers are positioned within valve chambers formed between the plurality of cylinder heads and head covers coupled to the cylinder heads;transmission mechanisms for reducing the rotational force of a crankshaft of the engine by half for transmission to the camshafts are provided between the crankshaft and the camshafts, said transmission mechanisms including endless chains wrapped around drive sprockets fixed to one end of the crankshaft and driven sprockets fixed to one end of the camshafts, said endless chains being housed in transmission chambers formed across the head covers, cylinder heads, cylinder blocks and crankcases such that first ends of the transmission mechanisms are in communication with the valve chambers and second ends of the transmission mechanisms face one end in the axial direction of the crankshaft; anda return hole for causing the lower part of said second end of the transmission chambers to communicate with the crank chambers, said return hole being provided in the crankcases.