Lubricant supplying system for dohc type multi-cylinder internal

Abstract

A lubricant supplying system for a DOHC type multicylinder internal combustion engine comprising a plurality of cylinders arranged in series in a cylinder block, a pair of cam shafts parallel to each other and rotatably supported by a cylinder head and cam holders fixed to the cylinder head at opposite sides of the respective cylinders along the cylinder arranging direction, a plurality of cams including low speed cams corresponding to intake and exhaust valves of the respective cylinders and fixed to the cam shafts, a plurality of rocker arms in slidable contact with the respective cams corresponding to the intake and exhaust valves of the respective cylinders, and a connection switching mechanism for switching connection and disconnection of the rocker arms in response to a hydraulic pressure to vary the operating states of the valves responsive to the operating state of the engine, wherein a hydraulic pressure supply passage independent from an oil supply passage for supplying a hydraulic pressure to the connection switching mechanism is provided in the cylinder head substantially at its center portion along the cylinder arranging direction so as to extend vertically, and a branch oil passage is provided to have intake and exhaust side portions disposed in one cam holder of substantially center location along the cylinder arranging direction for communicating with the upper end of the hydraulic pressure supply passage to supply oil to the slidably contacting portions of low speed cams of the respectively cylinders at both intake and exhaust sides with the rocker arms and the cam journal portions of the cam shafts.