Polaris Industries Inc.

Jan M Hedlund

Richard Allen Fredrickson

Richard Harold Bates

Lyle Jay Dahlgren

Kevin D Ness

Jack R Olson

Jim Vizanko

John Bradley Bosch

Aaron J Johnson

An engine air intake system for vehicles such as snowmobiles. The air intake system helps prevent airborne contaminants from entering the vehicle engine through the air intake. The intake includes an elongated channel with openings on either end that provides a throughway for contaminants entering the channel. A wall of the channel includes at least one aperture leading to an intake port on an engine cylinder. The intake port is positioned generally parallel to the direction of airflow through the channel.

Engine air intake system

A snowmobile having asymmetrical, high floatation skis. The snowmobile includes left and right steerable skis carried by a front suspension system that in turn is mounted to the snowmobile's chassis. Each ski has a downwardly extending longitudinal keel, and inner and outer floatation portions extending laterally from the keel. The inner floatation portion of each ski is wider than the outer floatation portion of such ski, making the ski asymmetrical with respect to the keel and giving the ski greater floatation without increasing the overall width of the snowmobile. Preferably the front suspension system includes left and right generally downwardly and forwardly extending spindles, each spindle carrying at its lower end the corresponding ski. The spindles define the steering axes for their respective skis. Preferably the steering axis of the spindle passes through the keel. The angle of the spindles in combination with the asymmetrical skis causes the ski on the inside of a turn to lose floatation in comparison to the outer ski, thus causing the snowmobile to lean into the turn.

Snowmobile with asymmetric skis

A variable exhaust resonance chamber valve system for internal combustion engine. The engine includes a cylinder having an exhaust port with an axial extent along the axis of the cylinder structure. An exhaust passage having a resonance port extends from the exhaust port to exhaust the engine. A resonance chamber extends from the resonance port and communicates with the exhaust passage through the resonance port. A port valve is adjustable between a second position, in which the port valve exposes the exhaust port throughout its axial extent and occludes the resonance port, and a first position, in which the port valve restricts the axial extent of the exhaust port and exposes the resonance port. A valve control module is connected to the port valve and functions to adjust the port valve between first and second positions in response to engine conditions. At low speeds and low output conditions, the valve is in its first position. At higher speeds and under higher output conditions, the valve control module moves the valve to its second position.

Varible exhaust resonance chamber valve system for two-cycle engines

A snowmobile having a liquid-cooled engine with an improved cooling system is disclosed. The snowmobile has a chassis with a drive tunnel. Horizontal footrests extend laterally from opposite sides of the chassis. The snowmobile also has left and right elongate side coolers that dissipate heat generated by the engine. The side coolers have a hollow interior that is in fluid communication with liquid coolant passages in the engine. Each cooler extends longitudinally and is mounted at an outer edge of a respective footrest to form a footwell. The snowmobile has a pump that circulates coolant throughout the coolant circuit formed by the side coolers and the internal passages of the engine. The side coolers may also contain heat exchanging anti-skid studs that extend outward from the surface of each side cooler. The snowmobile may also contain front and rear heat exchangers connected within the coolant circuit and positioned at the front and rear ends of the tunnel, respectively.

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Roseau, MN, United States of America

Jan M Hedlund