Internal-combustion engines – Charge forming device – Multiple carburetors
Reexamination Certificate
1999-12-02
2001-03-27
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Multiple carburetors
Reexamination Certificate
active
06205986
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an intake device for a V-type engine for synchronizing the carburetors of multiple cylinders of a V-type engine.
(2) Description of the Prior Art
In a typical V-type intake device for multi-cylinder engine for a motorcycle, each of the multiple cylinders has a separate carburetor, so there is the necessity of making synchronized control of the multiple carburetors. Japanese Utility Model Application Laid-Open Sho 60 No.61468 discloses an intake device in which the throttle shafts of the carburetors of the front and rear cylinders of a V-type engine are laid out coaxially on a line connected between the centers of the two carburetors (slightly inclined with respect to the line of center of the vehicle) and coupled to each other to thereby achieve synchronized control of multiple carburetors.
In an intake device configuration where the throttle shafts of multiple carburetors are merely connected as disclosed in Japanese Utility Model Application Laid-Open Sho 60 No.61468, there is a chance that the synchronization may be disordered if the carburetors are displaced relative to each other by vibrations and/or other reasons. To deal with this, as shown in
FIG. 1
, bodies
131
and
141
of carburetors
130
and
140
of the front and rear cylinders of a V-type engine may be connected to each other by means of linkage plates
150
and
150
so as to achieve an improved synchronized control of the two carburetors
130
and
140
.
In this case, linkage plates
150
and
150
are arranged parallel to the vehicle's center line CL (perpendicular to the crankshaft) and attached to carburetors
130
and
140
by fasteners
159
,
159
, . . . , on both transverse sides of them. Since front and rear carburetors
130
and
140
are offset to opposite sides from each other, the attachment should be done with interposing spacers
158
and
158
, . . . . Throttle shafts
136
and
146
of carburetors
130
and
140
are positioned perpendicular to the vehicle's center line CL and are coupled by a coupling linkage
160
which is parallel to linkage plates
150
.
Thus, in the above intake device, the transversal distance between linkage plates
150
and
150
is large, increasing the weight and raising the cost. Further, since the transversal distance between linkage plates
150
and
150
is large, large overhangs of throttle shafts
136
and
146
(large projections of the shafts from bodies
131
and
141
) need to be formed in order to couple throttle shafts
136
and
146
by means of coupling linkage
160
. As a result, this configuration may cause increasing of the friction, being likely to be affected by dimensional errors and being low in its operativity.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an intake device for a V-type engine in which the carburetors of multiple cylinders can be precisely synchronized. In order to achieve the above object, the present invention is configured as follows:
In accordance with the first aspect of the present invention, an intake device for a V-type engine having first and second cylinders being offset to the sides opposite to each other, wherein first and second carburetors are mounted in alignment with the centers of the first and second cylinders, respectively, and the throttle shafts of the first and second carburetors are coupled to each other, is characterized in that the body of the first carburetor and the body of the second carburetor are coupled by linkage plates arranged in parallel with the line that joins the center of the first carburetor and that of the second carburetor, and the throttle shaft of the first carburetor and the throttle shaft of the second carburetor are laid out perpendicular to the linkage plates and coupled to each other by means of a coupling linkage which is in parallel with the linkage plates.
In accordance with the second aspect of the present invention, the intake device for a V-type engine having the above first feature is characterized in that a throttle cable is connected to one of the throttle shafts and a cable support for supporting the throttle cable is formed in the linkage plate.
In accordance with the third and fourth aspects of the present invention, the intake device for a V-type engine having the above first or second feature is characterized in that the first and second carburetors have their intake channels inclined along respective V-bank sides, and the float chamber of the first carburetor and the float chamber of the second carburetor are provided on the V-bank sides.
In accordance with the first feature of the present invention, since the relative displacement of the first and second carburetors can be reduced by means of the linkage plates while at the same time increasing the transversal distance due to the attachment of the linkage plates and the increase in the overhangs of the throttle shafts for attachment of the coupling linkage can be suppressed. Accordingly, it is possible to precisely synchronize the first and second carburetors without degrading the operativity and durability of the carburetors and throttle. It is also possible to suppress increase of the attachment space, weight and cost, which would occur if the intake device was bulky.
In accordance with the second feature of the present invention, it is possible to couple the carburetor's bodies with each other by the linkage plates and the throttle cable can be supported simply.
In accordance with the third and fourth features of the present invention, it is possible to set the float chambers at lower positions.
REFERENCES:
patent: 4445466 (1984-05-01), Zaita et al.
patent: 4474144 (1984-10-01), Tanaka et al.
patent: 4517940 (1985-05-01), Koyanagi et al.
patent: 60-61468 (1985-04-01), None
Nojima Tetsuo
Sonoda Yuji
Darby & Darby
McMahon Marguerite
Suzuki Motor Corporation
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