Patent ID: 8137425

Claim:
An intake system for a vehicle internal combustion engine, comprising: an air cleaner box that has a first air intake opening, a second air intake opening and a communication opening that communicates with an intake port of the vehicle internal combustion engine; a first air intake duct that has an air intake inlet and is connected to the air cleaner box such that air is inhaled from the air intake inlet into the air cleaner box through the first air intake opening; a second air intake duct that is connected to the air cleaner box such that air is inhaled into the air cleaner box through the second air intake opening, wherein the air intake inlet is farther apart from the air cleaner box than the second air intake duct is; and an on-off valve that is provided in the second air intake duct such that air is inhaled into the air cleaner box through the first air intake opening when the on-off valve is closed, and air is inhaled into the air cleaner box through both of the first air intake opening and the second air intake opening when the on-off valve is opened, wherein the cross section area of the second air intake duct is greater than the cross section area of the first air intake duct, and the first air intake duct and the second air intake duct are disposed such that a center axis of the second air intake duct at an end portion on a side of the second air intake opening intersects with a center axis of the first air intake duct at an end portion on a side of the first air intake opening.