JPH0350094B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a motorcycle equipped with a V-type engine, and in particular, a V-type engine equipped with a carburetor having one throttle valve per cylinder. Regarding motorcycles.

(Prior art) Generally, in engines that require high output such as motorcycle engines, each cylinder has a
Carburetors with several throttle valves are commonly used. This also applies to V-type engines for motorcycles (hereinafter referred to as V-type engines).
In the V-type engine described above, a butterfly type throttle valve is disposed in each intake passage of each cylinder.

(Problem to be Solved by the Invention) On the other hand, in recent years, in view of exhaust gas countermeasures, it has been desired to accurately synchronize the opening degrees of throttle valves (throttle opening degrees) in the intake passages of each cylinder.
However, for example, with the conventionally commonly used means of synchronizing the opening and closing of each throttle valve by connecting the throttle lever of each throttle valve to a Bowden wire, etc., the opening and closing of each throttle valve may not be accurate due to aging of the Bowden wire, etc. synchronization becomes impossible, which is disadvantageous in terms of exhaust gas countermeasures. On the other hand, if the throttle shafts of each throttle valve are connected by a link device, deterioration over time will be reduced. However, since the carburetor is cantilevered by attaching the downstream end of its intake pipe to the tip of the intake hole of the cylinder,
For V-type engines where the carburetor is installed above each cylinder so that the intake pipe runs vertically, the distance between the front and rear carburetors is the same as the distance between the front and rear carburetors, excluding the lower end where they are attached to each cylinder. The distance between the throttle shafts changes slightly due to the external force applied to the carburetor, so even though each throttle shaft is connected by a link device that does not change easily over time, it is difficult to accurately control the opening of each throttle valve. It becomes impossible to synchronize, which is disadvantageous in terms of exhaust gas countermeasures.

The present invention was made in view of the above-mentioned circumstances, and its main purpose is to accurately synchronize the throttle opening of the throttle valve in the above-mentioned V-type engine even when an external force is applied to the carburetor. The purpose is to do so.

(Means for Solving the Problems) For this purpose, a motorcycle equipped with a V-type engine according to the present invention has a V-type engine mounted on the motorcycle with front and rear cylinders arranged so as to form a V-shape when viewed from the side. In a motorcycle equipped with a V-type engine in which the engine is equipped with a carburetor having one butterfly-type throttle valve per cylinder, the intake holes of each cylinder are arranged upward between the front and rear cylinders, The carburetor is arranged above the front and rear cylinders so that the axes of the intake pipes are in the vertical direction and the upper ends are closer to each other than the lower ends, and the lower end of each intake pipe is connected to the upper end of each intake hole. The throttle shafts of each of the throttle valves arranged in the front and back and extending in the left and right direction are connected by a link device, and one of the throttle shafts is rotated by an operating wire, so that the The upper end of each of the intake pipes is fixed to the lower part of a surge tank having an integral structure, which is disposed in a surge tank through which intake air passes, and the upper ends of the intake pipes are integrally connected to each other.

(Function) The lower ends of the intake pipes of each carburetor are attached to each cylinder, and the upper ends are fixed to the lower part of one integrally structured surge tank, so that they are integrally connected.
Even if various forces are applied to each vaporizer, the distance between them will not change. On the other hand, both throttle shafts are connected by a link device that does not change much over time. Therefore, regardless of the operating state of the motorcycle,
The opening degrees of each throttle valve are always accurately synchronized. Further, since the axes of the intake pipes are arranged such that the upper ends attached to each intake hole are closer to each other than the lower ends, the link device becomes more compact.

(Effects of the Invention) As described above, according to the present invention, the throttle openings of each throttle valve can always be accurately synchronized regardless of the usage condition of the motorcycle, so that exhaust gas countermeasures can be advantageously achieved. It can be carried out. In addition, because the front and rear intake pipes, especially their upper ends, are closer to each other, the linkage that connects the throttle valve becomes more compact, and the surge tank also becomes smaller, making the motorcycle's intake system more compact as a whole and improving its rigidity. can be done. Furthermore, since there is no intake air interference between the carburetors, it is possible to always achieve the desired performance.

(Example) Hereinafter, the present invention will be described based on the drawings. FIG. 1 shows an example of a motorcycle in which the present invention is implemented. This motorcycle has figures 1 to 3.
As shown in the figure, a four-cylinder V-type engine 10,
Front and rear cylinders 11a, 12a, 11 when viewed from the side
b, 12b are arranged and mounted in a V-shape, and the engine 10 has two carburetors 20.
a and 20b are connected. Front and rear cylinders 11
Between a, 12a, 11b, 12b, there is an intake hole 11 of each cylinder that connects each carburetor 20a, 20b.
1, 121, 112, and 122 are arranged facing upward.

As shown in FIG. 3, the carburetor 20a includes a pair of left and right intake pipes 21a, 22a and each intake pipe 21a, 2.
Float chamber 23 located approximately in the center between 2a
each intake pipe 21a,
Bench turrets 211, 221 provided in 22a
Main nozzles 213 and 223, which supply main fuel from the float chamber 23a through main jets 212 and 222, face the main nozzles 213 and 223, respectively. As shown in FIGS. 2 and 3, the main nozzles 213, 223
The fuel discharge port at the tip and the float chamber 23a are
Both are located approximately at the center of the longitudinal width of the intake passages Pa1 and Pa2. In addition, each intake pipe 21a, 22a
A throttle shaft 24a extending in the left-right direction is located on the lower end side of the ventilate portions 211, 221.
is airtightly penetrated and rotatably attached to each intake pipe 21 of the throttle shaft 24a.
Butterfly type throttle valves 25a and 26a are respectively fixed to portions inside a and 22a, and a throttle lever 27a is fixed to one end of the throttle shaft 24a.

This carburetor 20a is located above the pair of front cylinders 11a, 12a in the engine 10 so that the intake pipes 21a, 22a are vertically arranged, and the upstream end of the upper end of each intake pipe 21a, 22a is connected to the surge. It is airtightly fixed to the lower part of the tank 31 together with the funnels 311 and 312 located inside the tank 31, and the downstream end of the lower end is connected to the front cylinders 11a and 1.
It is airtightly fixed to the upper ends of the intake holes 111 and 112 of 2a. As a result, each intake pipe 21a,
22a and each intake passage Pa1 of the front cylinders 11a, 12a formed by the intake holes 111, 121,
Pa2 is a downward intake passage, that is, a substantially vertical intake passage with respect to the front cylinders 11a and 12a.

On the other hand, the vaporizer 20b, which is the same as the vaporizer 20a,
Similarly, a pair of rear cylinders 11 in the engine 10
b, 12b. The upper upstream end of each intake pipe 21b, 22b constituting this carburetor 20b is airtightly fixed to the lower part of the surge tank 31 together with funnels 313, 314 located inside the surge tank 31, and the downstream end of the lower end is rearward. It is airtightly fixed to the ends of the intake holes 112, 122 of the cylinders 11b, 12b. Thereby, the intake passage of the rear cylinders 11b, 12b formed by the respective intake pipes 21b, 22b and the intake holes 112, 122.
Pb1 and Pb2 form downward passages, that is, substantially vertical intake passages, with respect to the rear cylinders 11b and 12b.

On the other hand, like the throttle valves 25a and 26a, a throttle shaft 24b extends in the left-right direction.
Each throttle valve 25b, 26b fixed to
is adapted to be rotated in the same direction as each throttle valve 25a, 26a. In addition, each slow system fuel passage 28a of each carburetor 20a, 20b,
28b is also located on the same direction side (rear side) with respect to each of the intake passages Pa1, Pa2, Pb1, and Pb2. In this embodiment, as shown in FIG. 2, when each throttle shaft 24a, 24b rotates counterclockwise, that is, each throttle valve 25a,
When the throttle shafts 26a, 25b, and 26b rotate counterclockwise, the throttle opening increases, and when each throttle shaft 24a, 24b rotates clockwise from this state, the throttle opening decreases. There is. Note that the surge tank 31 is
Air cleaner 3 as shown in Figures 2 and 5.
2, air flows in as shown by the fifth arrow, is distributed within the surge tank 31, and is guided to each intake passage Pa1, Pa2, Pb1, Pb2. Further, the surge tank 31 is connected to a pipe line 31 that communicates with the crank chamber, so that blow-by gas is circulated into the surge tank 31.

As shown in FIG. 2, the surge tank 31 has one integral structure common to the front and rear carburetors 20a and 20b, and the intake pipes 21a and 22a and 21b and 22b of the front and rear carburetors 20a and 20b are The upper ends connected to the surge tank 31 are arranged closer to each other than the lower ends connected to the intake holes 111, 121 and 112, 122.

Therefore, each throttle shaft 24a, 24
Each throttle lever 27a fixed to one end of b,
27b, as shown in FIG.
1, each end of an operable connecting rod 42 is rotatably connected. Both ends of the operating wire 41 are attached to opposite sides of the throttle lever 27a, and when the operating wire 41 is operated, the throttle lever 27a rotates about its fixed portion, thereby rotating the throttle shaft 24a.
At the same time, the connecting rod 42 moves back and forth to rotate the throttle lever 27b,
The throttle shaft 24b, which is integrated with this, is rotated. As a result, the throttle valves 25a, 26a fixed to the throttle shaft 24a and the throttle valves 25b, 26b fixed to the throttle shaft 24b are rotated to open and close. That is, when the operation wire 41 is operated, each throttle valve 25a, 26a, 25b, 26
b are opened and closed in precise synchronization.

In the motorcycle configured in this way, each intake pipe 21a, 22 of each carburetor 20a, 20b is
a, 21b, 22b have their lower ends connected to the respective cylinders 11a, 1
2a, 11b, 12b, and the upper end is 1
Since it is fixed and integrally connected to the lower part of the surge tank 31, which has an integral structure, the operation wire 41
Even if a force from the connecting rod 42 or a force due to vibration is applied to each carburetor 20a, 20b, the distance between them does not change. Both throttle shafts 24a, 24b are connected to throttle levers 27a, 27b and connecting rod 4.
Since the throttle valves 25a and 26 are connected by a link device that does not change much over time, each throttle valve 25a, 26
The throttle openings of a, 25b, and 26b are always accurately synchronized. In addition, the front and rear cylinders 11a, 12
The front and rear intake pipes 21a, 22a, 21b, and 22b arranged between the connecting rods 4a, 11b, and 12b are particularly close to each other at their upper ends.
2 becomes shorter and the surge tank 31 also becomes smaller, making it possible to make the intake system of the motorcycle more compact as a whole and to improve its rigidity. Furthermore, since each of the carburetors 20a and 20b sucks air from the air cleaner 32 through the surge tank 31, there is no risk of intake interference between the carburetors.

Note that the present invention is not limited to the case where the intake pipes of the carburetors 20a and 20b are substantially vertical and slightly closer to each other on the upper end side as in the illustrated embodiment; It can also be applied to a case where the upper end portions are arranged in an eight-shape shape when viewed from above. Even in the case of this arrangement, each intake pipe 2
If the upper ends of 1a, 22a, 21b, and 22b are not connected, each upper end will be displaced separately and the distance between the throttle shafts 24a and 24b will change, making it impossible to accurately maintain synchronization of the throttle openings. Therefore, the same problem arises as in the case of the arrangement as in the illustrated embodiment, and the problem can be solved by applying the present invention.

[Brief explanation of drawings]

FIG. 1 is a left side view showing an example of a motorcycle according to the present invention, FIG. 2 is an enlarged vertical left side view showing essential parts of the present invention, and FIG. 3 is a cross-sectional view taken along the line -- in FIG.
4 is an enlarged right side view of the carburetor shown in FIG. 1, and FIG. 5 is a cross-sectional view taken along the line -- in FIG. 2. Explanation of symbols 10...Engine, 11a, 12a
...Front cylinder, 11b, 12b...Rear cylinder, 20
a, 20b... vaporizer, 21a, 22a, 21b,
22b...Intake pipe, 23a...Float chamber, 2
4a, 24b...Throttle shaft, 25a, 2
6a, 25b, 26b...throttle valve, 27
a, 27b... Throttle lever, 31... Surge tank, 32... Air cleaner, 41... Operation wire,
42... Connecting rod, 213, 223...
Main nozzle, Pa1, Pa2, Pb1, Pb2...Intake passage.

Claims (1)

[Claims] 1 A V-type engine installed in a motorcycle whose front and rear cylinders are arranged in a V-shape when viewed from the side.
In a motorcycle equipped with a V-type engine which is provided with a carburetor having one butterfly throttle valve per cylinder, the intake hole of each cylinder is arranged upward between the front and rear cylinders, and each carburetor is arranged between the front and rear cylinders. The intake pipes are arranged above the front and rear cylinders so that their axes are in the vertical direction and their upper ends are closer to each other than their lower ends, and the lower ends of each intake pipe are attached to the upper ends of each intake hole. The throttle shafts of each of the throttle valves, which are arranged in A motorcycle equipped with a V-type engine, characterized in that the upper ends of each of the intake pipes are fixed to the lower part of a surge tank having an integral structure through which intake air passes, and the upper ends of the intake pipes are integrally connected to each other.