Quiet snowmobile

Claim 2

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, an internaL combustion engine mounted on said frame within said compartment and including a cylinder, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, air inlet means located in one of said transverse partition, said hood, and said frame portion and communicating with said air supply chamber for affording entry of air into said air supply chamber, air outlet means in one of said transverse partition, said hood, and said frame portion, and communicating with said exiting air chamber for discharging air from said air exiting chamber, a muffler communicating with said cylinder and mounted in said exiting air chamber, and an exhaust gas discharge pipe communicating with said muffler and extending exteriorly from said compartment.

Claim 3

A snowmobile in accordance with claim 1 wherein said cylinder includes an exhaust port and wherein said engine further includes a second cylinder including an exhaust port and wherein said muffler is connected to one of said exhaust ports, and wherein said snowmobile further includes a second muffler mounted in said exiting air chamber and connected to the other of said exhaust ports, and a second exhaust gas discharge pipe extending from said second muffler to outside of said compartment.

Claim 4

A snowmobile in accordance with claim 2 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a first barrier spaced axially from one of said end wall and defining, with said one end wall, an end chamber, a second barrier spaced axially from said first barrier in the direction away from said one end wall and defining, with said first barrier, an outlet chamber, a third barrier spaced axially from said second barrier in the direction away from said one end wall and defining, with said second barrier, a central chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber connected to one of said exhaust ports and including an outlet portion terminating adjacent to said other end wall, a first pipe extending from said megaphone chamber to said central chamber, a second pipe extending from said central chamber to said end chamber, a third pipe extending from said end chamber to said exhaust chamber, and an exhaust discharge pipe having a discharge portion extending from said outlet chamber outwardly of said housing for connection with one of said exhaust gas discharge passages.

Claim 5

A snowmobile in accordance with claim 2 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a perforated baffle in adjacently spaced and parallel relation of one of said opposed end walls, a first barrier spaced axially from said perforated baffle in the direction away from said one end wall and defining, with said one end wall, an end chamber, another barrier spaced axially from said first barrier in the direction away from said one end wall and defining, with said first barrier, another chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber connected to one of said exhaust ports and including an outlet portion terminating adjacent to said other end wall, passage means connecting said megaphone chamber to said end chamber, a pipe extending from said end chamber to said other chamber, and an exhaust discharge pipe including a discharge portion extending from said other chamber outwardly of said housing for connection with one of said exhaust gas discharge passages.

Claim 6

A snowmobile in accordance with claim 2 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a perforated baffle in adjacently spaced and parallel relation of one of said opposed end walls, a first barrier spaced axially from said perforated baffle in the direction away from said one end wall and dEfining, with said one end wall, an end chamber, a second barrier spaced axially from said first barrier in the direction away from said one end wall and defining, with said first barrier, an outlet chamber, a third barrier spaced axially from said second barrier in the direction away from said one end wall and defining, with said second barrier, a central chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber and including an inlet portion extending radially outwardly from said megaphone chamber for connection with one of said exhaust ports and an outlet portion extending at a right angle to said inlet portion and terminating adjacent to said other end wall, a first tubular pipe extending from said megaphone chamber to said central chamber, a second tubular pipe extending from said central chamber to said end chamber, a third tubular pipe extending from said end chamber to said outlet chamber, and an exhaust discharge pipe having an inlet portion extending in said outlet chamber, and a discharge portion extending from said inlet portion and outwardly of said housing for connection with one of said exhaust gas discharge passages.

Claim 7

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber including an engine cooling air inlet, and an exiting air chamber including an air outlet for discharging cooling air from said exiting air chamber, an internal combustion engine mounted on said frame within said compartment and including a pair of cylinders each including an exhaust port, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with each of said cylinders and including an air inlet communicating with said air supply chamber, a first muffler mounted in said exiting air chamber and connected to one of said exhaust ports, a second muffler mounted in said exiting air chamber and connected to the other of said exhaust ports, and respective exhaust gas discharge passages extending from said mufflers to outside of said compartment.

Claim 8

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber including an engine cooling air inlet, and an exiting air chamber including an air outlet for discharging cooling air from said exiting air chamber, an internal combustion engine mounted on said frame within said compartment and including a pair of cylinders each including an exhaust port, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with each of said cylinders and including an air inlet communicating with said air supply chamber, a first muffler mounted in said exiting air chamber and connected to one of said exhaust ports, a second muffler mounted in said exiting air chamber and connected to the other of said exhaust ports, and respective exhaust gas discharge passages extending from said mufflers to outside of said compartment.

Claim 9

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, second wall means extending in said air supply chamber and dividing said air supply chamber into an entering air sub-chamber and a carburetor air supply sub-chamber and including means providing communication between said entering air sub-chamber and said carburetor air supply sub-chamber, an internal combustion engine mounted on said frame within said compartment and including a cylinder, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with said cylinder and including an air inlet communicating with said carburetor air supply sub-chamber, air inlet means located in one of said transverse partition, said hood and said frame portion and communicating with said air supply chamber for affording entry of air into said compartment, air outlet means in one of said Transverse partition, said hood, and said frame portion, and communicating with said exiting air chamber for discharging air from said compartment, a muffler mounted in said exiting air chamber and connected to said cylinder, and an exhaust gas discharge passage extending from said muffler to outside of said compartment.

Claim 10

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, second wall means extending in said air supply chamber and dividing said air supply chamber into an entering air sub-chamber and a carburetor air supply sub-chamber and including means providing communication between said entering air sub-chamber and said carburetor air supply sub-chamber, an internal combustion engine mounted on said frame within said compartment and including a cylinder, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with said cylinder and including an air inlet communicating with said carburetor air supply sub-chamber, air inlet means located in one of said transverse partition, said hood and said frame portion and communicating with said air supply chamber for affording entry of air into said compartment, air outlet means in one of said Transverse partition, said hood, and said frame portion, and communicating with said exiting air chamber for discharging air from said compartment, a muffler mounted in said exiting air chamber and connected to said cylinder, and an exhaust gas discharge passage extending from said muffler to outside of said compartment.

Claim 11

A snowmobile in accordance with claim 7 wherein said cylinder includes an exhaust port and wherein said engine further includes a second cylinder including an exhaust port and said muffler is connected to one of said exhaust ports, and wherein said snowmobile further includes a second muffler mounted in said exiting air chamber and connected to the other of said exhaust ports, and a second exhaust gas discharge passage extending from said second muffler to outside of said compartment.

Claim 12

A snowmobile in accordance with claim 8 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a first barrier spaced axially from a perforated baffle in the direction away from said one end wall and defining, with said one end wall, an end chamber, a second barrier spaced axially from said first barrier in the direction away from said one end wall and defining, with said first barrier, an outlet chamber, a third barrier spaced axially from said second barrier in the direction away from said one end wall and defining, with said second barrier, a central chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber and including an outlet portion terminating adjacent to said other end wall, a first pipe extending from said megaphone chamber to said central chamber, a second pipe extending from said central chamber to said end chamber, a third pipe extending from said end chamber to said outlet chamber, and an exhaust discharge pipe having a discharge portion extending from said outlet chamber outwardly of said housing.

Claim 13

A snowmobile in accordance with claim 8 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a perforated baffle in adjacently spaced and parallel relation of one of said opposed end walls, a first barrier spaced axially from said perforated baffle in the direction away from said one end wall and defining, with said one end wall, an end chamber, a second barrier spaced axially from said first barrier in the direction away from said one end wall and defining, with said first barrier, an outlet chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber connected to one of said exhaust ports and including an outlet portion terminating adjacent to said other end wall, passage means connecting said megaphone chamber to said end chamber, a pipe extending from said end chamber to said outlet chamber, and an exhaust discharge pipe including a discharge portion extending from said outlet chamber outwardly of said housing for connection with one of said exhaust gas discharge passages.

Claim 14

A snowmobile in accordance with claim 8 wherein one of said mufflers comprises a generally tubular housing having opposed end walls, a perforated baffle in adjacently spaced and parallel relation of one of said opposed end walls, a first barrier spaced axially from said perforated baffle in the direction away from said one end wall and defining, with said one end wall, an end chamber, a second barrier spaced axially from said first barrier in a direction away from said one end wall and defining, with said first barrier, an outlet chamber, a third barrier spaced axially from said second barrier in the direction away from said one end wall and defining, with said second barrier, a central chamber and defining, with the other of said opposed end walls, a megaphone chamber, a single exhaust megaphone in said megaphone chamber and including an inlet portion extending radially outwardly from said megaphone chamber for connection with one Of said exhaust ports and an outlet portion extending at a right angle to said inlet portion and terminating adjacent to said other end wall, a first tubular pipe extending from said megaphone chamber to said central chamber, a second tubular pipe extending from said central chamber to said end chamber, a third tubular pipe extending from said end chamber to said exhaust chamber, and a discharge portion extending from said inlet portion and outwardly of said housing for connection with one of said exhaust gas discharge passages.

Claim 15

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, second wall means extending in said air supply chamber and dividing said air supply chamber into an entering air sub-chamber and a carburetor air supply sub-chamber and including a port providing communicating between said entering air sub-chamber and said carburetor air supply sub-chamber, an internal combustion engine mounted on said frame within said compartment and including a pair of cylinders each having a piston operable therein and including an exhaust port, said pistons having a total displacement less than the volume of said carburetor air supply sub-chamber, an engine cooling system including means defining an engine cooling air passage communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with each of said cylinders and including an air inlet communicating with said carburetor air supply sub-chamber, a first muffler mounted on said frame in said exiting air chamber and connected to one of said exhaust ports, a second muffler mounted on said frame in said exiting air chamber and connected to the other of said exhaust ports, respective exhaust gas discharge passages extending from said mufflers to outside of said compartment, baffle air inlet means located in one of said transverse partition, said hood, and said frame portion and communicating with said entering air sub-chamber for affording entry of air into said compartment, at least one baffle extending in said carburetor air supply sub-chamber and transversely of the path of air flow to said carburetor inlet, a battery located in said entering air sub-chamber in the path of air flow to said port, a fuel pump in said air supply chamber, and baffled air outlet means in one of said transverse partition, said hood, and said frame portion, and communicating with said exiting air chamber for discharging air from said compartment.

Claim 16

A snowmobile comprising a frame including a generally horizontally extending portion, a transverse partition extending upwardly from said horizontal frame portion, a hood extending from said frame portion to said transverse partition and defining with said frame portion and said transverse partition a substantially closed compartment, first wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, second wall means extending in said air supply chamber and dividing said air supply chamber into an entering air sub-chamber and a carburetor air supply sub-chamber and including a port providing communicating between said entering air sub-chamber and said carburetor air supply sub-chamber, an internal combustion engine mounted on said frame within said compartment and including a pair of cylinders each having a piston operable therein and including an exhaust port, said pistons having a total displacement less than the volume of said carburetor air supply sub-chamber, an engine cooling system including means defining an engine cooling air passage communicating between said air supply chamber and said exiting air chamber, and a carburetor operably communicating with each of said cylinders and including an air inlet communicating with said carburetor air supply sub-chamber, a first muffler mounted on said frame in said exiting air chamber and connected to one of said exhaust ports, a second muffler mounted on said frame in said exiting air chamber and connected to the other of said exhaust ports, respective exhaust gas discharge passages extending from said mufflers to outside of said compartment, baffle air inlet means located in one of said transverse partition, said hood, and said frame portion and communicating with said entering air sub-chamber for affording entry of air into said compartment, at least one baffle extending in said carburetor air supply sub-chamber and transversely of the path of air flow to said carburetor inlet, a battery located in said entering air sub-chamber in the path of air flow to said port, a fuel pump in said air supply chamber, and baffled air outlet means in one of said transverse partition, said hood, and said frame portion, and communicating with said exiting air chamber for discharging air from said compartment.

Claim 17

A snowmobile comprising a frame including a generally forwardly located substantially closed compartment, wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, an internal combustion engine mounted in said compartment and including a cylinder, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, air inlet means for affording entry of air into said air supply chamber, air outlet means for affording discharge of air from said exiting air chamber, a muffler communicating with said cylinder and mounted in said exiting air chamber, and an exhaust gas discharge pipe communicating with said muffler and extending exteriorly from said compartment.

Claim 18

A snowmobile comprising a frame including a generally forwardly located substantially closed compartment, wall means extending in said compartment and dividing said compartment into an air supply chamber and an exiting air chamber, an internal combustion engine mounted in said compartment and including a cylinder, an engine cooling system including means defining an engine cooling air passage for directing cooling air past said engine and communicating between said air supply chamber and said exiting air chamber, air inlet means for affording entry of air into said air supply chamber, air outlet means for affording discharge of air from said exiting air chamber, a muffler communicating with said cylinder and mounted in said exiting air chamber, and an exhaust gas discharge pipe communicating with said muffler and extending exteriorly from said compartment.