An off-road vehicle includes an air intake system that comprises an opening that, in operation, receives air, and an exhaust system that includes an exhaust stack positioned in the opening of the air intake system.

In an air cleaner for a vehicle, a connection part of a first intake duct to a cleaner case is disposed in a front half portion of one of left and right half portions of the cleaner case, the first intake duct including a first air inlet port opening forward. A connection part of a second intake duct to the cleaner case is disposed in a rear half portion of an other of the left and right half portions, the second intake duct including a second air inlet port opening rearward. The first intake duct is formed to include a first air outlet port opening rearward inside an unpurified chamber and curve in an up-down direction in a side view, and the second intake duct is formed to include a second air outlet port opening forward inside the unpurified chamber and curve in a right-left direction in a plan view.

A ventilation duct includes an intake port through which fluid is sucked in a different direction from an up-down direction; a discharge port that is located above the intake port; a connecting portion that connects the intake port and the discharge port, and a duct inner surface that is an inner surface of the connecting portion, the duct inner surface being provided such that a fluid channel is provided inside the duct inner surface. A wall portion is provided to linearly extend upward from a lower surface of the duct inner surface and to extend in a right-left direction when seen from an upstream side in a flow direction of the fluid flowing through the fluid channel.

A compressor bypass reintroduction system includes a compressor intake manifold and a bypass conduit. The compressor intake manifold defines a fluid plenum. The compressor intake manifold is engageable with a compressor. The bypass conduit extends into the fluid plenum and includes an ejector line. The ejector line is configured to be substantially collinear with the compressor and to discharge flow toward the compressor. In some embodiments, an outlet of the ejector is disposed proximate to an outlet of the fluid plenum that discharges flow into the compressor.

An engine intake air duct 1 has an intake portion 10 that extends along a first center line A, and a main duct portion 20 that extends along a second center line B. The main duct portion 20 has a merging portion 50, a discharge opening 21, and an extending portion 40 that extends from the merging portion 50 towards an opposite end to the discharge opening 20. A reflecting wall 41 is provided at an end face of the extending portion 40. The intake portion 10 merges with the main duct portion 20 in such a way that the first center line A is directed towards a downstream end of the main duct portion 20.

Substances in external EGR gas are smoothly guided to a combustion chamber. An intake passage includes: a main intake passage including intake ports and communicating with a combustion chamber and having a supercharger interposed in the main intake passage; and a bypass passage branching off from the main intake passage upstream of the supercharger, and connected downstream of the supercharger; a flow rage adjustment valve changing a cross-sectional flow area of the bypass passage. The bypass passage is provided above the main intake passage, and includes an upper passage to which an EGR passage is connected.

An off-road vehicle includes an air intake system that comprises an opening that, in operation, receives air, and an exhaust system that includes an exhaust stack positioned in the opening of the air intake system.

In an air cleaner for a vehicle, a connection part of a first intake duct to a cleaner case is disposed in a front half portion of one of left and right half portions of the cleaner case, the first intake duct including a first air inlet port opening forward. A connection part of a second intake duct to the cleaner case is disposed in a rear half portion of an other of the left and right half portions, the second intake duct including a second air inlet port opening rearward. The first intake duct is formed to include a first air outlet port opening rearward inside an unpurified chamber and curve in an up-down direction in a side view, and the second intake duct is formed to include a second air outlet port opening forward inside the unpurified chamber and curve in a right-left direction in a plan view.

An engine intake air duct 1 has an intake portion 10 that extends along a first center line A, and a main duct portion 20 that extends along a second center line B. The main duct portion 20 has a merging portion 50, a discharge opening 21, and an extending portion 40 that extends from the merging portion 50 towards an opposite end to the discharge opening 20. A reflecting wall 41 is provided at an end face of the extending portion 40. The intake portion 10 merges with the main duct portion 20 in such a way that the first center line A is directed towards a downstream end of the main duct portion 20.

A ventilation duct includes an intake port through which fluid is sucked in a different direction from an up-down direction; a discharge port that is located above the intake port; a connecting portion that connects the intake port and the discharge port, and a duct inner surface that is an inner surface of the connecting portion, the duct inner surface being provided such that a fluid channel is provided inside the duct inner surface. A wall portion is provided to linearly extend upward from a lower surface of the duct inner surface and to extend in a right-left direction when seen from an upstream side in a flow direction of the fluid flowing through the fluid channel.