Engine including motorized throttle valve

An engine, comprising:

• a cylinder head joined to an upper end face of a cylinder block having three or more cylinders disposed in series to each other;
• a head cover connected to an upper end face of the cylinder head;
• a valve system accommodated in a valve chamber defined by and between the cylinder head and the head cover and including first and second camshafts extending in parallel to each other;
• a plurality of throttle bodies disposed at a side of the valve chamber and corresponding to the cylinders;
• an electric motor connected to a valve shaft for throttle valves, for opening and closing intake paths of the throttle bodies, and configured to drive the throttle valves to open or close;
• and
• a gear train configured to transmit output power of the electric motor to the valve shaft,
• wherein the electric motor is disposed at one side of the group of the throttle bodies with the speed reduction mechanism being disposed between a second pair of predetermined throttle bodies, said second pair of predetermined throttle bodies being disposed at a different location in the group of the throttle bodies with respect to the first pair of predetermined throttle bodies,
• wherein the electric motor is disposed between the valve chamber and the group of the throttle bodies in an offset relationship from an enlarged portion of the valve chamber in an axial direction of the first and second camshafts, and
• wherein the gear train comprises:
• a pinion gear attached to the electric motor;
• a first gear meshing with the pinion gear;
• and
• a second gear attached to the valve shaft meshing with the first gear,
• wherein the second gear is sector shaped.