JPH0853088A - Intake device for vehicle engine - Google Patents

Abstract

(57) [Abstract] [Purpose] A sufficient air passage area can be secured to enhance the ram air effect, the layout is not unreasonable, and the two intake ducts are symmetrical and excellent in design, and intake noise is reduced. (EN) Provided is a vehicle engine intake device that can be reduced. [Structure] On the front side of the fairing 8, a pair of air intakes 12, 12 are opened symmetrically on both sides of a central headlight 11 with a central axis L therebetween. And the two air intakes 12 on both sides and the air suction port 9 of the air cleaner 9
a and independent intake ducts 13 ・ 1 each having a symmetrical shape
3 are connected via a bifurcated connecting duct 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle engine in which outside air is introduced into a carburetor through an air cleaner using traveling wind pressure (ram pressure), and a mixture mixed with fuel in the carburetor is introduced into a combustion chamber. More particularly, the present invention relates to an intake device suitable for effectively guiding air to an air cleaner of an engine in a motorcycle equipped with a fairing.

[0002]

2. Description of the Related Art The above fairing has the effect of rectifying the air received during traveling, reducing the air resistance, and improving the styling of motorcycles.
Fairing is widely used in motorcycles. However, when the fairing is attached, the front surface of the motorcycle is covered, so that introduction of air into the air cleaner is likely to be hindered.

Therefore, there has been proposed an intake system for a motorcycle in which an air intake is opened in the fairing and the outside air is guided from this air intake to an air cleaner by an intake duct (tube). JP-A-63-18458
The intake device described in Japanese Patent Publication No. 2 is also an example. This intake device opens air intakes on both upper and lower sides of the headlight of the fairing and below the headlight, respectively, and connects the intake ducts to the air cleaners through the steering handles from the air intakes on both upper sides. Further, the air intake duct on the lower side has a structure in which an intake duct is connected to an air cleaner through a pair of front forks and below the head pipe.

In addition, in order to make the difference between the pressure in the float chamber of the carburetor and the negative pressure in the venturi part constant in an intake device of the type in which the outside air is introduced into the air cleaner by using the running wind pressure as in the above intake device. ,
An intake device having a structure in which a front end opening of an air vent passage communicating with an upper space of a float chamber is provided near an air intake of an intake duct is described in, for example, Japanese Utility Model Laid-Open No. 3-87856. This intake device is a so-called single duct having one intake duct for introducing outside air into the air cleaner, and whether the intake duct penetrates the head pipe,
Alternatively, it is connected to the air suction port of the air cleaner by bypassing the head pipe.

[0005]

However, the former of the intake devices described in the above publications introduces outside air to the air cleaner by means of three intake ducts, which complicates the ducts and their arrangement. In addition, since these ducts are arranged so as to bypass the steering handle or the head pipe, the length of the ducts becomes longer, and the ducts are bent at the bypass points, so that they flow through each duct. The resistance of the air guided to the air cleaner increases. Therefore, the running wind pressure of the motorcycle cannot be effectively used to introduce the outside air into the air cleaner.

Since the latter is a single duct, if an attempt is made to secure a sufficient intake passage area, there is a possibility that the necessary strength of the head pipe cannot be secured when the intake pipe is arranged so as to penetrate the head pipe. is there. On the other hand, when the head pipe is detoured, the duct layout becomes asymmetrical, which is not preferable in terms of design, and the air flow resistance at the detouring portion (bent portion) becomes large. In addition, if an attempt is made to secure a sufficient air passage area even at the detour area, the outer shape of the duct becomes large, which causes the inconvenience that the layout and shape of the peripheral components (main frame, fuel tank, etc.) must be changed. Occurs. Furthermore, since the front end opening of the air vent passage (running air pressure intake) is provided near the air intake of the intake duct, when there is a cross wind, the area around that opening becomes negative pressure and the carburetor float The pressure balance between the chamber and the venturi part may be lost.

The present invention has been made in view of the above points, and introduces the outside air to the air cleaner by using two independent intake ducts from the two air intakes.
A sufficient air passage area can be secured to enhance the ram air effect, the layout is reasonable, the two intake ducts are symmetrical, and the design is excellent, and intake noise can be reduced.
Another object of the present invention is to provide an air intake device for a vehicle engine, which can reduce the diameter of the duct hole even when the intake duct is passed through the main frame and ensure the required strength of the main frame.

Further, when the ram air is introduced into the venturi portion of the carburetor, the upper space of the float chamber is pressurized through the air vent passage to balance the pressure between the venturi portion and the float chamber, and at the same time, to receive a crosswind. However, another purpose is to prevent the pressure balance from being lost.

[0009]

In order to achieve the above-mentioned object, the intake system of the present invention introduces outside air into a carburetor through an air cleaner using traveling wind pressure, and mixes the air-fuel mixture with the fuel in the carburetor. In an intake system for a vehicle engine introduced into a combustion chamber, air intakes are provided in front of the vehicle symmetrically with respect to a central axis thereof,
The respective air intakes and the air suction port of the air cleaner are connected by independent air intake ducts.

When the vehicle is a motorcycle having a fairing, the air intakes are opened on both sides of the front of the fairing, and the air intakes and the air intakes of the air cleaners are independent of each other. It is preferable to connect by a symmetrical intake duct. Further, the intake ducts on both sides may be formed integrally with the fairing.

According to a fourth aspect of the present invention, the front end opening of the air vent passage communicating with the upper space of the float chamber of the carburetor is disposed forward in the vicinity of the air intake of each of the intake ducts. Alternatively, as described in claim 5, it is desirable to provide a front end opening of the air vent passage communicating with the upper space of the float chamber of the carburetor in the central portion of the fairing.

[0012]

According to the intake device of the present invention having the above structure,
When the vehicle is running, the outside air is introduced into the intake ducts from the air intakes on both sides of the front face and is guided to the air intake port of Ecreena through the two intake ducts. Since the two intake ducts are completely independent and the air passage area is sufficiently secured, the intake noise is reduced and the ram air effect utilizing the traveling wind pressure is effectively exhibited. In addition, since the outer shape (caliber) of each intake duct can be made smaller than in the case where there is only one intake duct, there is no difficulty in layout, and the duct hole diameter can be made smaller when the intake duct is passed through the main frame. , It becomes easy to secure the necessary strength of the mainframe.

Particularly when the intake device of the present invention is applied to a motorcycle equipped with a fairing, the left and right intake ducts are formed symmetrically to achieve weight balance and an excellent design. become. In addition, by forming each intake duct integrally with the fairing, there is no wasted space, resulting in a compact design. And since the outside air is taken in from the front of the motorcycle, the temperature of the intake air to the engine is lowered and the air density due to natural supercharging is increased because the running wind is introduced
The output of the engine can be improved. The pressure increase (Δρ) due to the traveling wind is derived by the following mathematical formula.

[0014] That ^{is, △ ρ = γ × V 2} / 2g × 10 -4 where, gamma: air density (kg / m ³⁾ V: running wind (km
/ h) According to the intake device of claim 4 or 5, when the ram air is introduced into the venturi portion of the carburetor, the ram air pressure acts on the upper space in the float chamber of the carburetor through the air vent passage. The pressure difference between the float chamber and the float chamber is kept constant, and an appropriate air-fuel ratio is obtained. In addition, when a cross wind is received, the front end opening of the air vent passage is located on both sides (air intake) or the center of the fairing. However, since the positive pressure is generated around the other opening and the negative pressure is less likely to be negative around the opening in the case of the central portion, the pressure balance between the venturi portion and the float chamber is properly maintained.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the intake system of the present invention applied to a motorcycle engine will now be described with reference to the drawings.

FIG. 1 is a side view showing an outline of a motorcycle provided with an intake device according to this embodiment, FIG. 2 is an enlarged plan view showing a main part of a front half of the motorcycle of FIG. 1, and FIG. Figure 2
And FIG. 4 is a side view of FIG.

As shown in FIG. 1, in the motorcycle A,
One end of a pair of main frames 2 forming a part of the vehicle body frame is joined to both sides of the head pipe 1, and an engine 3 is mounted near the lower portion of the main frame 2.
A pair of front forks (not shown) is connected to the head pipe 1, and a front wheel 4 is suspended. A rear wheel 5 is suspended at the rear end of the vehicle body frame via a pair of rear arms (not shown). A fuel tank 6 is provided behind the head pipe 1 and at the upper end of the vehicle body frame.
The seat 7 is attached behind it. The fairing 8 is attached from the front surface of the vehicle body to the front half portions on both sides. In the figure, reference numeral 9 is an air cleaner, reference numeral 10 is a carburetor, and the rear end of the intake duct 13 is connected to the air suction port 9a (FIG. 4) of the air cleaner 9.
4 (FIG. 4).

As shown in FIG. 3, on the front surface of the fairing 8, a pair of air intakes 12.1 are symmetrically disposed on both sides of the central headlight 11 with the central axis line LL interposed therebetween.
2 has been opened. As shown in FIG. 2, the two air intakes 12 on both sides and the air suction port 9a of the air cleaner 9 are independent symmetrical symmetrical intake ducts 13 and
It is connected by 13. Intake ducts 13 on both sides
The rear end of 13 is a branch portion 14 of a bifurcated connecting duct 14.
The connection duct 14 is connected to the front end of a, and the rear end of the connection duct 14 is connected to the air suction port 9 a of the air cleaner 9. The rear end portion of each intake duct 13 is passed directly above the main frame 2, or is passed through the main frame 2 and is guided to the air suction port 9a of the air cleaner 9. Reference numeral 15 in FIG. 2 is a handle shaft, and 16 is a steering handle. The positions of the air intakes 12 on both sides may be below the headlight 11 on the front surface of the fairing 8 (position C in FIG. 3).

The intake duct 13 is formed in a surging tank 13a by expanding an intermediate portion thereof downward as shown in FIG. The surging tank 13a reduces the flow velocity of the air passing through the duct 13,
Rainwater and the like that enter the duct 13 from 2 are separated from the air and are stored in the surging tank 13a. And
Since the collected rainwater and the like are discharged from a drain (not shown) provided at the bottom of the surging tank 13a, they do not enter the air cleaner 9. The intake duct 13 may be formed separately from the fairing 8 and attached along the inner wall of the fairing 8.
It can also be formed integrally with. Especially the intake duct 13
If is formed integrally with the fairing 8, it is finished compactly and no wasted space is generated.

Inside each of the air inlets 12, a front end opening 17a of an air vent tube (air vent passage) 17 is attached to the front, and the air vent tube 17 is taken out from the middle of the intake duct 13 as shown in FIG. Figure 4
As described above, the rear end is communicated with the upper space of the float chamber 10a of the carburetor 10. Engine 3
When (FIG. 1) includes a plurality of cylinders (for example, four cylinders) and a plurality of carburetors 10 corresponding to the number of cylinders is provided, one of the left and right air vent tubes 17 is partially (first and second cylinders). The other carburetor may be communicated with the remaining (third and fourth cylinder) carburetors, or the left and right air vent tubes 17 may be assembled into one to form one carburetor. May be branched to communicate with each other.

Alternatively, one air vent tube 17 is provided, and the opening 17a at the front end thereof is arranged at the center position (position B in FIG. 3) of the fairing 8 which is not easily affected by cross wind.
The other end of the air vent tube 17 may be communicated with the float chamber 10a of the carburetor 10.

According to the intake device of the present embodiment having the above-mentioned structure, when the motorcycle A is traveling, the outside air is supercharged by the traveling wind pressure, and the ram air is inhaled from the air intake ports 12 on both sides. Air cleaner 9 through duct 13
Will be introduced to. And this ram air is carburetor 1
No. 0 venturi portion 10b (FIG. 4), and at the same time, the float chamber 10a is pressurized by the ram air pressure from the front end opening 17a of the air vent tube 17, 17 disposed at each air intake 12, 12. . As a result, the venturi portion 10b and the float chamber 1 are
The pressure difference from 0a is kept constant, and an appropriate air-fuel ratio is obtained.

Although the above-described embodiment is applied to a motorcycle engine, it is needless to say that the present invention is not limited to a motorcycle engine, but can be applied to an engine of a motorcycle or an automobile.

[0024]

As is apparent from the above description,
The intake system for a vehicle engine of the present invention has the following effects.

(1) Since the outside air is guided to the air cleaner by using two independent intake ducts from the two air intakes, it is possible to secure a sufficient air passage area for enhancing the ram air effect and to improve the layout. There is no reason why.
Moreover, the intake noise can be reduced, and the duct hole diameter can be reduced even when the intake duct is passed through the main frame, so that the required strength of the main frame can be secured. 2 more
Since the intake duct of the book is symmetrical, there is no discomfort,
It is also excellent in design.

(2) In the intake device according to the second aspect, the left and right intake ducts are formed symmetrically, so that weight balance is achieved and the design is further improved.

(3) In the air intake device according to the third aspect of the invention, since each air intake duct is formed integrally with the fairing, there is no wasted space, and the air intake device is finished compactly.

(4) In the intake device according to claim 4 or 5,
When introducing ram air into the venturi part of the carburetor, the upper space of the float chamber is pressurized via the air vent passage, so the pressure balance between the venturi part and the float chamber is achieved, and an appropriate air-fuel ratio is obtained. . In addition, even when a cross wind is received, the front end opening of the air vent passage is located on both sides (air intake) or the center of the fairing. Around the other opening is positive pressure,
Further, in the case of the central portion, a negative pressure is unlikely to occur around the opening, so that the pressure balance between the venturi portion and the float chamber is not easily lost.

[Brief description of drawings]

FIG. 1 is a side view showing an outline of a motorcycle including an intake device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a main part of a front half of the motorcycle shown in FIG.

FIG. 3 is a front view of FIG. 2;

FIG. 4 is a side view of FIG. 2, partly in cross section.

[Explanation of symbols]

 1 Head Pipe 2 Main Frame 3 Engine 8 Fairing 9 Air Cleaner 10 Carburetor 12 Air Intake 13 Intake Duct 17 Air Vent Tube (Air Vent Passage) A Motorcycle

[Procedure amendment]

[Submission date] June 5, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a side view showing an outline of a motorcycle including an intake device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a main part of a front half of the motorcycle shown in FIG.

FIG. 3 is a front view of FIG. 2;

FIG. 4 is a side view of FIG. 2, partly in cross section.

FIG. 5 is a plan view showing a front half portion of a motorcycle provided with an intake device according to another embodiment of the present invention.

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a plan view showing a front half portion of a motorcycle provided with an intake device according to still another embodiment of the present invention.

FIG. 8 is a side view of FIG. 7;

[Explanation of reference symbols] 1 head pipe 2 main frame 3 engine 8 fairing 9 air cleaner 10 carburetor 12 air intake 13 intake duct 17 air vent tube (air vent passage) A motorcycle

Claims (5)

[Claims] 1. An intake system for a vehicle engine in which outside air is introduced into a carburetor through an air cleaner using traveling wind pressure, and the mixture mixed with fuel in the carburetor is introduced into a combustion chamber. An air intake device for a vehicle engine, wherein air intakes are provided symmetrically with respect to an axis, and the respective air intakes and the air intake of the air cleaner are connected by independent air intake ducts. 2. The motorcycle is a motorcycle having a fairing, wherein the air intakes are opened on both sides of the front surface of the fairing, and the air intakes and the air intakes of the air cleaners are independent of each other. The intake system for a vehicle engine according to claim 1, wherein the intake systems are connected by symmetrical intake ducts. 3. The intake system for a vehicle engine according to claim 2, wherein the intake ducts on both sides are formed integrally with the fairing. 4. A front end opening of an air vent passage communicating with an upper space of a float chamber of the carburetor,
The intake system for a vehicle engine according to any one of claims 1 to 3, wherein the intake system is arranged near the air intake port of each intake duct toward the front. 5. A front end opening of an air vent passage communicated with an upper space of a float chamber of the carburetor,
The intake system for a vehicle engine according to claim 2 or 3, wherein the intake system is provided in a central portion of the fairing.