Patent ID: 6532914
Filing Date: 2003-03-18
Classification: F01L,F02B,F05C

Abstract:
A four-cycle internal combustion engine comprising a cylinder block defining a cylinder bore, a piston reciprocally disposed within the cylinder bore, a cylinder head member closing an end of the cylinder bore to define a combustion chamber together with the cylinder bore and the piston, the cylinder head member defining an inner passage having a first end communicating with the combustion chamber and a second end opening at an exterior surface of the cylinder head member, a valve assembly having a valve section and an actuateable section, the valve section selectively placed at an open position and a closed position to connect and disconnect the inner passage with the combustion chamber, respectively, the actuateable section being formed oppositely from the valve section, a valve actuation mechanism arranged to actuate the actuateable section to move the valve section between the open position and the closed position, the cylinder head member further defining a guide opening through which the actuateable section is slideably disposed, and an external conduit defining an outer passage communicating with the inner passage, the external conduit depending from an end portion of the cylinder head member, the cylinder head member defining a recessed portion disposed between the guide opening and the second end of the inner passage, wherein the inner passage, the valve assembly and the external conduit are an exhaust inner passage, an exhaust valve assembly and an exhaust conduit, respectively, and together define an exhaust system through which exhaust gases are discharged from the combustion chamber, additionally comprising a fastener to affixing the external conduit to the cylinder head member, wherein the second end of the inner passage forms a mounting boss, and the fastener is connected to the mounting boss, wherein the fastener includes a bolt, the mounting boss defines a bolt hole into which the bolt is fitted, and an imaginary cylindrical portion extending straight along an axis of the bolt hole toward the valve assembly from the bolt hole intersects, at least in part, the recessed portion.