JPH06221238A - Intake device for motorcycle - Google Patents

Abstract

PURPOSE:To reduce intake resistance so as to increase an intake amount and the freedom degree of design. CONSTITUTION:A carburetor 5 is provided in front of an engine 2, and enclosed by the main body 7 of an intake box 6. The front part of the main body 7 is communicated with a pair of light and left duct parts 8 extending upward, and the top end part of the duct part 8 a is formed in leading inlet part 9 which is bent forward. A steamlining plate 15 is provided inside extending from the leading inlet part 9 to a space above the duct part 8, and also a cuving part 16 is provided in the vicinity of a bending part 17. Generation of turbulence is suppressed in the duct part 8 by the steamlining plate 15 so as to reduce intake air resistance, and also the opening area of the leading inlet part 9 is enlarged so as to increase an intake air amount, and it is possible to set the position of the leading inlet part 9 comparatively freely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for a motorcycle, and more particularly to the structure of an intake box provided around a carburetor.

[0002]

2. Description of the Related Art As an intake device for a motorcycle, a device in which a carburetor is surrounded by an intake box and the intake pressure is increased by a ram pressure is known (as an example, a full-open sho 61-146480). (See the official gazette). Also, in the type in which the carburetor is installed in front of the engine, the intake box surrounding the carburetor is located behind the front wheels, so the duct part extends upward from the main body of the intake box, and its upper end bends forward. It is also conceivable to use it as the inlet.

[0003]

By the way, if the intake box is provided with the inlet portion which is bent forward and is opened above the carburetor as described above, the inlet box is taken in from the inlet portion. Since the streamline of the traveling wind is bent downward at an acute angle in the upper part of the duct part, the pressure in this part increases. Moreover, as the speed increases, the pressure in the bent portion following the inlet portion increases and the intake resistance increases.

As a result, as the speed increases, a larger ram pressure needs to be applied to the carburetor, but due to this intake resistance, the ram pressure of an appropriate magnitude corresponding to the speed is not applied and a sufficient output is obtained. In some cases, it may be difficult to obtain, and there is a design restriction on the setting position of the introduction port. Furthermore, if the opening area of the inlet is increased to increase the intake air volume, turbulence is likely to occur inside. As a result, the ram pressure is affected, so the opening area of the inlet is also designed. The above restrictions occur. Then, this invention aims at solving the said problem.

[0005]

In order to solve the above problems, an intake system for a motorcycle according to the present invention comprises an intake box, the intake box including a main body portion surrounding a carburetor, and the main body portion. Of the duct part, which extends upward from the front, and an inlet part which is bent forward at the upper end part of the duct part and opens to a position above the carburetor, and which is continuous from the inside of the inlet part to the inside of the duct part and introduced. A straightening plate having a smooth curved surface at a portion corresponding to a bent portion formed between the mouth portion and the duct portion is provided, and the outside air taken in from the inlet portion is smoothly allowed to flow downward in the duct portion. To do.

[0006]

The running wind taken into the introduction port flows from the introduction port to the duct along the current plate. At this time,
Since the portion of the straightening plate corresponding to the bent portion formed between the introduction port portion and the duct portion has a smooth curved surface, the traveling wind smoothly flows downward in the duct portion. Also, the occurrence of turbulence is reduced. Therefore, the pressure rise at the bent portion is reduced to reduce the intake resistance, and the ram pressure of a sufficient magnitude corresponding to the speed is given to the carburetor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is a view showing a left side shape of a motorcycle for racing to which the present invention is applied, with a part of a fairing part cut away.

A V-type 2-cycle 4-cylinder engine 2 is supported on a main frame 1 which is paired left and right and extends in the front-rear direction. The engine 2 is provided with front cylinders 3 that are slanted forward and two rear cylinders 4 that are tilted slightly forward and stand up, and two carburetors 5 are attached to the bank portions of the front and rear cylinders.

The carburetor 5 is located in front of the engine 2 and is surrounded by the main body portion 7 of the intake box 6. The intake box 6 is provided with a duct portion 8 that extends from the front of the main body portion 7 in a pair to the left and right, and an inlet portion 9 that is bent forward from the upper end of the main body portion 7 and opens.

The left and right duct parts 8 are located on the left and right sides of the front wheel 10, and the inlet part 9 is located near the top of the front wheel 10 so as to overlap the front fender 11 and the front fork 12. The intake box 6 is inside the fairing 13, and the introduction port 9 projects slightly forward from the air guide port for the radiator 14 formed in the fairing 13.

The radiator 14 is of a vertically divided type, and the upper one is supported by the main frame 1 and is located above the main body portion 7 and on the back surface of the duct portion 8 and is connected to the duct portion 8. As is clear from this figure, the inlet port 9 is the carburetor 5.
Is located above the main wheel 7, and the main body 7 is located behind the front wheel 10.

FIG. 1 is a partially cutaway and enlarged view of an intake device portion including an intake box 6. From the inlet portion 9 to the upper surface of the duct portion 8 and inside thereof, the rectifying plate 1
5 are integrally provided.

The current plate 15 has a curved portion 16 having a smooth curved surface, and this curved portion 16 has an inlet 9 and a duct 8.
It is located in a portion corresponding to the inside of the bent portion 17 formed between them. In the figure, reference numeral 18 is a suction port of the carburetor 5, and 19 is a net attached to the suction port.

Four carburetors 5 are arranged side by side corresponding to each cylinder, and each is connected to each intake port 21, 22 of the front cylinder 3 and the rear cylinder 4 via an insulator 20. As is clear from the drawing, the side wall portion 23 of the main body portion 7 through which the insulator 20 penetrates is fixed to the intake ports 22 and 21 by bolts 24.

Next, the operation of this embodiment will be described. In FIG. 2, the traveling wind W enters inward from the introduction port 9 and goes upward of the duct part 8, but at the bent part 17, the duct part is smoothly bent along the curved surface of the curved part 16 formed on the straightening vane 15. 8 and flow downwards, and the duct 8
It enters into the main body portion 7 from the lower part of and is supplied to the suction port 18 of the carburetor 5 there.

Therefore, while traveling, the suction port 1 of the vaporizer 5
The air supplied to 8 is pressurized by the ram pressure to improve the output of the engine 2.

Further, even if the speed becomes high, the inlet port 9
Due to the presence of the flow straightening plate 15, the traveling wind W taken in from does not increase the local pressure in the bent portion 17 so much and smoothly flows into the duct portion 8. In addition, the generation of turbulence in the duct portion 8 is suppressed.

Therefore, since the intake resistance in the intake box 6 is reduced by providing the straightening plate 15, it is possible to apply a ram pressure of a sufficient magnitude to the carburetor 5 according to the speed. Further, the position and opening area of the inlet port 9 can be set relatively freely, and it becomes relatively easy to increase the intake amount, which can contribute to the improvement of output and increase the degree of freedom in design. .

[0019]

The intake device according to the present invention serves as an intake box, a main body portion surrounding the carburetor, a duct portion extending upward from the front of the main body portion, and an upper end portion of the duct portion bent forward to be vaporized. And an inlet opening to a position higher than the container, which is continuous from the inlet to the duct,
In addition, the straightening vane is provided in which the portion corresponding to the bent portion formed between the introduction port portion and the duct portion has a smooth curved surface.

Therefore, since the carburetor is provided in front of the engine, the inlet of the intake box is located above the carburetor, and the bent portion is formed between the inlet and the duct. In addition, since the intake resistance in the intake box is reduced and the generation of turbulence is suppressed, the traveling wind taken in from the inlet can be smoothly flowed into the duct and supplied to the carburetor. As a result, the carburetor can be inhaled in a pressurized state with a sufficiently large ram pressure according to the speed change,
The output can be improved.

Moreover, since the position of the inlet port can be set relatively freely and the opening area thereof can be easily increased, the intake amount can be increased and at the same time, the intake box, especially the inlet port. The degree of freedom in design regarding structure and arrangement is increased.

[Brief description of drawings]

FIG. 1 is a partially cutaway enlarged view of a main part of an embodiment.

FIG. 2 is a side view of a main part of a motorcycle to which the embodiment is applied.

[Explanation of symbols]

2 ... Engine, 3 ... Front cylinder, 4 ... Rear cylinder, 5 ... Vaporizer,
6 ... Intake box, 7 ... Main body part, 8 ... Duct part, 9 ... Inlet port part, 15 ... Rectifier plate, 16 ... Curved part, 17 ... Bent part

Claims (1)

[Claims] 1. An intake system for a motorcycle comprising a carburetor mounted in front of an engine and an intake box surrounding the carburetor, wherein the intake box includes a main body portion surrounding the carburetor and the main body. A duct portion extending upward from the front of the portion, and an inlet portion that is bent forward at the upper end portion of the duct portion and opens at a position above the carburetor, and is continuous from inside the inlet portion to inside the duct portion, and A straightening plate with a smooth curved surface corresponding to the bent portion formed between the inlet port and the duct part was provided, and the outside air taken in from the inlet part was made to smoothly flow downward inside the duct part. An intake device for a motorcycle.