Snowmobile having noise-suppression engine compartment

Claim 2

A snowmobile comprising a frame including a generally hroizontally extending forward portion and a tunnel portion extending rearwardly from said frame portion, an endless track mounted in said tunnel portion, a seat located above said tunnel portion, a transverse partition located forwardly of said seat and extending upwardly from said frame portion, a hood extending forwardly of said transverse partition and above said frame portion and defining with said frame portion and said transverse partition a substantially closed engine compartment, wall means extending in said engine compartment dividing said engine compartment into an air supply chamber and an exiting air chambEr, an internal combustion engine located in said engine compartment, air inlet means located in one of said transverse partition, said hood, and said frame portion for introducing ambient air into said air supply chamber, means defining an air passage communicating between said air supply chamber and said exiting air chamber, means within said engine compartment for pumping air from said air supply chamber into said exiting air chamber through said air passage means to pressurize said exiting air chamber, air outlet means in one of said transverse partition, said hood, and said frame portion and remotely spaced from said air inlet means for discharging air from said air exiting chamber, and a muffler located in said exiting air chamber and positioned relative to said air outlet means so as to be in the flow path of the air flowing through said exiting air chamber and discharging through said air outlet means.

Claim 3

A snowmobile according to claim 1 wherein said muffler is positioned relative to said air outlet means to baffle the air flowing through said air outlet means.

Claim 4

A snowmobile according to claim 2 including means located in said exiting air chamber and cooperating with said muffler and said frame portion to define a substantially closed air discharge sub-chamber in which said muffler is located and through which at least a portion of the air entering said exiting air chamber through said air passage means flows in contact with the outer surface of said muffler before being discharged from said exiting air chamber through said air outlet means.

Claim 5

A snowmobile according to claim 3 wherein said engine includes an exhaust gas port and said snowmobile further includes means located in said air discharge subchamber for connecting said muffler to said engine exhaust port.

Claim 6

A snowmobile according to claim 3 wherein said air discharge sub-chamber defining means includes a shield supported on said frame in said exiting air chamber, positioned above said muffler, and defining with said frame portion and said muffler and annular-like air flow passage partially surrounding the outer surface of said muffler.

Claim 7

A snowmobile according to claim 5 wherein said air discharge sub-chamber defining means further includes a generally inverted U-shaped baffle supported on said frame in said exit air chamber, partially surrounding said muffler connecting means, extending from said shield towards said air passage means outlet, and defining with said muffler connecting means and said frame portion an air flow passage which communicates with said annular flow passage and said air passage means.

Claim 8

A snowmobile according to claim 5 wherein said shield includes one or more air inlet openings for admitting air from said exiting air chamber into said annular flow passage.

Claim 9

A snowmobile according to claim 7 wherein said shield also includes a generally horizontally extending flap hooding said shield air inlet opening so as to minimize the emission of radiant heat from said muffler into said exiting air chamber through said shield air inlet opening.

Claim 10

A snowmobile according to claim 1 wherein said engine includes a rotary output shaft, wherein said air passage means comprises an engine cooling system including means defining an engine cooling air passage directing the flow of air over said engine and communicating between said air supply chamber and said exiting air chamber, and wherein said pumping means comprises a fan located in said engine cooling air passage and operably connected to said rotary output shaft.

Claim 11

The snowmobile according to claim 1 wherein said air outlet means is located in said frame portion and wherein said muffler is located forwardly of said air outlet means.

Claim 12

A snowmobile according to claim 1 wherein said tunnel portion includes a forward end, and wherein said air outlet means is located in said frame portion forwardly of and generally adjacent to said tunnel forward end.

Claim 13

A snowmobile according to claim 11 wherein saId air outlet means is a transversely extending, slotted opening in said frame portion.

Claim 14

A snowmobile according to claim 12 wherein said muffler includes an exhaust gas discharge outlet means extending through said slotted opening.

Claim 15

A snowmobile according to claim 1 including an additional air outlet means in the upper portion of one of said hood and said transverse partition for discharging air from said exiting air chamber.

Claim 16

A snowmobile according to claim 14 including a headlight mounted on said hood and wherein said additional air outlet means comprises an aperture located adjacent to said headlight so that the air exiting from said exiting air chamber through said aperture flows in contact with said headlight.

Claim 17

A snowmobile comprising a frame including a generally horizontally extending forward portion and a tunnel portion extending rearwardly from said frame portion and having a forward end, an endless track mounted in said tunnel portion, a seat located above said tunnel portion, a transverse partition located forwardly of said seat and extending upwardly from said frame portion, a hood extending forwardly of said transverse partition and above said frame portion and defining with said frame portion and said transverse partition a substantially closed engine compartment, wall means extending in said engine compartment and dividing said engine compartment into an air supply chamber and an exiting air chamber, an internal combustion located in said engine compartment and including an exhaust port and a rotary output shaft, an engine cooling system including means defining an engine cooling air passage communicating between said air supply chamber and said exiting air chamber and having an outlet in said exiting air chamber, air inlet means located in one of said transverse partition, said hood, and said frame portion for introducing ambient air into said air supply chamber, air outlet means in said frame portion including means defining an air outlet port in said frame portion and located forwardly of said tunnel portion forward end for discharging air from said exiting air chamber and beneath said snowmobile, a fan operably connected to said engine rotary output shaft for pumping air from said air supply chamber into said exiting air chamber through said engine cooling air passage so as to pressurize said exiting air chamber, a muffler located in said exiting air chamber forwardly of said air outlet port, exhaust gas discharge outlet means extending from said muffler to outside said engine compartment, means connecting said muffler with said engine exhaust port, and a generally horizontal, transversely extending shield supported on said frame in said air exiting chamber, positioned above said muffler and defining with said frame portion and said muffler an annular-like air flow passage which partially surrounds the outer surface of said muffler and through which at least a portion of the air flowing into said exiting air chamber from said engine cooling air passage outlet passes before being discharged from said exiting air chamber through said air outlet port.

Claim 18

A snowmobile comprising a frame including a generally horizontally extending forward portion and a tunnel portion extending rearwardly from said frame portion and having a forward end, an endless track mounted in said tunnel portion, a seat located above said tunnel portion, a transverse partition located forwardly of said seat and extending upwardly from said frame portion, a hood extending forwardly of said transverse partition and above said frame portion and defining with said frame portion and said transverse partition a substantially closed engine compartment, wall means extending in said engine compartment and dividing said engine compartment into an air supply chamber and an exiting air chamber, an internal combustion located in said engine compartment and including an exhaust port and a rotary output shaft, an engine cooling system including means defining an engine cooling air passage communicating between said air supply chamber and said exiting air chamber and having an outlet in said exiting air chamber, air inlet means located in one of said transverse partition, said hood, and said frame portion for introducing ambient air into said air supply chamber, air outlet means in said frame portion including means defining an air outlet port in said frame portion and located forwardly of said tunnel portion forward end for discharging air from said exiting air chamber and beneath said snowmobile, a fan operably connected to said engine rotary output shaft for pumping air from said air supply chamber into said exiting air chamber through said engine cooling air passage so as to pressurize said exiting air chamber, a muffler located in said exiting air chamber forwardly of said air outlet port, exhaust gas discharge outlet means extending from said muffler to outside said engine compartment, means connecting said muffler with said engine exhaust port, and a generally horizontal, transversely extending shield supported on said frame in said air exiting chamber, positioned above said muffler and defining with said frame portion and said muffler an annular-like air flow passage which partially surrounds the outer surface of said muffler and through which at least a portion of the air flowing into said exiting air chamber from said engine cooling air passage outlet passes before being discharged from said exiting air chamber through said air outlet port.

Claim 19

A snowmobile according to claim 16 further including a baffle at least partially surrounding said muffler connecting means, extending from said shield towards said engine cooling air passage outlet, and defining with said muffler connection means and said frame portion an air flow passage which communicates with said annular flow passage and said engine cooling air passage outlet.

Claim 20

A snowmobile according to claim 16 including an additional air outlet port in the upper portion of one of said hood and said transverse partition for discharging air from said exiting air chamber.