Patent ID: 7523727

Claim:
An engine comprising: a cylinder head ( 14 ) forming a portion of an engine body ( 11 ); an intake valve operating device ( 28 ) having an intake camshaft ( 30 ); an intake valve ( 20 ) driven for opening and closing operations by the intake valve operating device ( 28 ), the intake valve ( 20 ) being provided in the cylinder head ( 14 ); an exhaust valve operating device ( 33 ) having an exhaust camshaft ( 35 ); and an exhaust valve ( 21 ) driven for opening and closing operations by the exhaust valve operating device ( 33 ), the exhaust valve ( 21 ) being provided in the cylinder head ( 14 ), characterized in that the intake camshaft ( 30 ) is placed higher in position than the exhaust camshaft ( 35 ) by increasing the distance between the intake camshaft ( 30 ) and a combustion chamber ( 17 ) along a cylinder axis (C) of the engine body ( 11 ) relative to the distance between the exhaust camshaft ( 35 )and the combustion chamber ( 17 ), wherein the intake valve operating device ( 28 ) has a variable lift mechanism ( 32 ) capable of changing the valve opening lift amount of the intake valve ( 20 ), and the exhaust valve operating device ( 33 ) has the exhaust camshaft ( 35 ) and an exhaust rocker arm ( 36 ) linked and connected to the exhaust valve ( 21 ) so as to swing by following the exhaust camshaft ( 35 ), and wherein the intake valve operating device ( 28 ) includes the intake camshaft ( 30 ) having an intake valve operating cam ( 29 ), an intake rocker arm having a cam contact portion ( 50 ) which contacts the intake valve operating cam ( 29 ), the intake rocker arm ( 31 ) being liked and connected to the intake valve ( 20 ) so as to apply a force to the intake valve ( 20 ) in the valve opening direction, and the variable lift mechanism ( 32 ), and wherein the variable lift mechanism ( 32 ) has a first link arm ( 58 ) having one end thereof turnably connected to the intake rocker arm ( 31 ) and the other end turnably supported at a fixed position on the engine body ( 11 ) through a fixed supporting shaft ( 57 ), and a second link arm ( 59 ) having one end thereof turnably connected to the intake rocker arm ( 31 ) and the other end turnably supported on a movable supporting shaft ( 60 ) capable of being displaced.