Patent ID: 7249587
Filing Date: 2007-07-31
Classification: F02D

Abstract:
1. An air-intake device of an engine for a leisure vehicle, in which at least two air-intake passages are arranged within a cylinder head of the engine, the air-intake device comprising: an air-intake pipe having a passage through which fresh air is supplied to the at least two air-intake passages arranged within the cylinder head; and a throttle valve openably mounted within the passage of the air-intake pipe; wherein the passage of the air-intake pipe has an air-flow cross-section of a non-perfect circle shape in a direction perpendicular to a longitudinal direction of the air-intake pipe, and the non-perfect circle shape is substantially an elongated circle shape having long and short axes or substantially an oval shape having long and short axes; wherein the throttle valve has a valve disc of a non-perfect circle shape conforming to the shape of the air-flow cross-section of the passage of the air-intake pipe; wherein an area of the air-flow cross-section of a portion of the air-intake pipe that is located in the vicinity of the air-intake passage of the cylinder head, gradually decreases toward the air-intake passage, and with a first taper angle of an inner wall of the air-intake pipe which is formed when sectioned along the long axis of the air-flow cross-section and with a second a taper angle of the inner wall of the air-intake pipe which is formed when sectioned along the short axis, the first taper angle being configured to be smaller than the second taper angle.