Abstract: A vehicle is shown such as a snowmobile, where a frame includes a tunnel and a front frame portion comprised of cast halves. A suspension system is comprised of upper and lower control arms connected to the front frame portion. Some of the frame components are adhesively fixed together. A powertrain is supported by the frame, and is comprised of an engine and a clutch. The clutch includes a clutch guard supporting an oil container. The engine has an exhaust system which extends through the front frame portion. The snowmobile also has a rear snow deflector.

Abstract: An air intake system for a vehicle is disclosed. The air intake system may include a first plenum housing having a fluid inlet and a fluid outlet and a fluid directing member which receives air from the fluid inlet of the plenum housing and directs the air away from the fluid outlet of the plenum housing.

Abstract: A vehicle is shown such as a snowmobile, where a frame includes a tunnel and a front frame portion comprised of cast halves. A suspension system is comprised of upper and lower control arms connected to the front frame portion. Some of the frame components are adhesively fixed together. A powertrain is supported by the frame, and is comprised of an engine and a clutch. The clutch includes a clutch guard supporting an oil container. The engine has an exhaust system which extends through the front frame portion. The snowmobile also has a rear snow deflector.

Abstract: An air intake system for a vehicle is disclosed. The air intake system may include a first plenum housing having a fluid inlet and a fluid outlet and a fluid directing member which receives air from the fluid inlet of the plenum housing and directs the air away from the fluid outlet of the plenum housing.

Abstract: 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.

Abstract: 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.

Abstract: In a microprocessor-based electronic engine control system or ECU for electronic fuel injection which determines the amount of fuel to be injected on the basis of engine RPM and throttle opening position, modified by factors derived from sensed conditions of the engine and the environment, a single, long pulse width priming fuel pulse is injected upon cranking the engine. The priming fuel pulse is selected as an inverse function of engine temperature and delivered to the throttle bodies within a first period of time after the engine is initially turned over. The engine revolutions are counted until the engine starts. If the engine fails to reach a predetermined RPM for a predetermined time period (indicating that it has been successfully started) within a certain number of revolutions of the crankshaft, then a second priming pulse is delivered. The pulse width of the second pulse is independent of the pulse width of the first priming pulse but is again dependent on the engine temperature.