Motor vehicles – Power – With means for handling motor exhaust
Reexamination Certificate
2002-01-22
2004-04-13
Johnson, Brian L. (Department: 3618)
Motor vehicles
Power
With means for handling motor exhaust
C180S296000, C180S215000
Reexamination Certificate
active
06719084
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exhaust system for a vehicular two-cylinder engine and, more particularly, to an exhaust system suitable for an automotive two-cylinder v-engine mounted on a straddle-type all-terrain vehicle.
2. Description of the Related Art
Conventional exhaust systems for a vehicular two-cylinder engine are classified into those provided with a single muffler for two cylinders and those provided with two mufflers respectively for two cylinders.
FIG. 7
is an exploded perspective view of a conventional exhaust system for a two-cylinder V-engine mounted on a motorcycle. This exhaust system is provided with a single muffler
105
. The exhaust system includes a front-cylinder exhaust pipe
100
, a rear-cylinder exhaust pipe
101
, a collecting pipe
102
having an outlet
103
, and the muffler
105
provided with a connecting pipe
106
. The outlet
103
of the collecting pipe
102
is connected to the connecting pipe
106
of the muffler
105
. The front-cylinder exhaust pipe
100
is extended rearward under the crankcase of the two-cylinder engine and is connected to the connecting pipe
106
of the muffler
105
disposed behind the two-cylinder engine via collecting pipe
102
.
An exhaust system including two mufflers respectively for the two cylinders of a two-cylinder engine has two exhaust pipes each having one end connected to the cylinder and the other end connected to the muffler.
The exhaust system shown in
FIG. 7
needs the collecting pipe
102
of complicated construction, many connecting parts for connecting the exhaust pipes
100
and
101
to the collecting pipe
102
, complicated piping and troublesome assembling work.
The exhaust system provided with the two mufflers for two cylinders needs spaces for the two mufflers.
When a two-cylinder V-engine is mounted on a saddle-type all-terrain vehicle, and the front-cylinder exhaust pipe is extended rearward under the crankcase, the exhaust pipe is close to the surface of the ground. Therefore, the exhaust pipe is easily covered and dirtied with mud and sand. The pipes must be arranged in a compact piping securing a sufficient road clearance, i.e., clearance between the front-cylinder exhaust pipe and the surface of the ground, to avoid the front-cylinder exhaust pipe striking against stones and rocks.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an exhaust system for an automotive two-cylinder engine, consisting of a relatively small number of parts and facilitating work for mounting the exhaust system on a vehicle.
Another object of the present invention to provide an exhaust system for a two-cylinder V-engine mounted on an all-terrain vehicle, including exhaust pipes and a muffler, which the exhaust pipes are extended so that a space around the cylinders of the two-cylinder V-engine may be effectively utilized, the all-terrain vehicle may have a relatively small overall width and the exhaust pipes may not be dirtied with mud and sand and may not strike against stones and rocks.
According to a first aspect of the present invention, an exhaust system for a vehicular two-cylinder engine having a first cylinder and a second cylinder includes a single muffler provided with two connecting openings, a first-cylinder exhaust pipe having one end connected to the first cylinder and the other end connected to one of the connecting openings of the muffler, and a second-cylinder exhaust pipe having one end connected to the second cylinder and the other end connected to the other connecting opening of the muffler, wherein at least either the first-cylinder or the second-cylinder exhaust pipe is connected detachably to the connecting opening of the muffler. Thus the exhaust system does not need the collecting pipe having complicated construction, the exhaust pipes can be extended in a simple arrangement, and the exhaust system facilitates assembling work.
Preferably, in the exhaust system in the first aspect of the present invention, the first muffler is a front cylinder disposed at a front portion with respect to a moving direction of a vehicle, the second muffler is a rear cylinder disposed at a rear portion with respect to the moving direction of the vehicle, the second-cylinder exhaust pipe is connected to the connecting opening and is welded to the muffler, and the first-cylinder exhaust pipe is connected detachably to the connecting opening. Connection of the second-cylinder exhaust pipe connected to the rear cylinder nearer to the muffler by welding further facilitates assembling work.
According to a second aspect of the present invention, an exhaust system for a two-cylinder V-engine having a front cylinder and a rear cylinder and mounted on a saddle-type all-terrain vehicle, said exhaust system includes a muffler disposed behind the two-cylinder V-engine, a front-cylinder exhaust pipe having one end connected to a front cylinder, the front cylinder being disposed at a front portion with respect to a moving direction of a vehicle, and a rear-cylinder exhaust pipe having one end connected to a rear cylinder, the rear cylinder being disposed at a rear portion with respect to the moving direction of the vehicle, wherein the front-cylinder exhaust pipe is bent so as to extend rearward along side surfaces of the front and the rear cylinder to the muffler. Thus the long front-cylinder exhaust pipe of the exhaust system can be extended through a dead space around the side surfaces of the front and the rear cylinders so that the same may not protrude laterally and hence the exhaust system has compact construction.
Preferably, in the exhaust system in the second aspect of the present invention, the muffler is provided with two connecting openings, the rear-cylinder exhaust pipe is connected to one of the connecting opening and is welded to the muffler, and the front-cylinder exhaust pipe is connected detachably to the connecting opening. Connection of the rear-cylinder exhaust pipe connected to the rear cylinder nearer to the muffler by welding further facilitates assembling work.
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Kawamoto Yuichi
Kuji Yasuhiro
Johnson Brian L.
Kawasaki Jukogyo Kabushiki Kaisha
Phan Hau
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