JP2704369B2 - Vehicle engine intake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In recent years, the above-mentioned fairing not only has the effect of rectifying the air received during traveling and reducing the air resistance, but also improves the styling of a motorcycle.
Attaching a fairing to a motorcycle is actively performed. However, when the fairing is mounted, the front of the motorcycle is covered, so that introduction of air to the air cleaner is likely to be hindered.

Accordingly, there has been proposed an intake device for a motorcycle in which an air intake is opened in a fairing and outside air is introduced from the 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 one example. This intake device opens the air intake on both sides of the headlight of the fairing and below the headlight, and connects the intake duct to the air cleaner through the steering handle from the air intake on both upper sides, The air intake duct on the lower side is connected to the air cleaner through a space between the pair of front forks and below the head pipe.

[0004] In addition, in an intake device of a type in which outside air is introduced into an air cleaner by using a traveling wind pressure similarly to the above-mentioned intake device, in order to make a difference between a pressure in a float chamber of a carburetor and a negative pressure in a venturi section constant. ,
For example, Japanese Utility Model Laid-Open No. 3-87856 discloses an air intake device having a structure in which a front end opening of an air vent passage communicated with an upper space of a float chamber is provided near an air intake of an intake duct. This intake device is a so-called single duct with one intake duct for introducing outside air to the air cleaner, and 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, in the former of the intake devices described in the above publication, the outside air is guided to the air cleaner by three intake ducts, so that the duct and its arrangement are complicated. In addition, since these ducts are arranged so as to bypass the steering handle or the head pipe, the length of the ducts is increased, 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 traveling wind pressure of the motorcycle cannot be effectively used for introducing outside air into the air cleaner.

Since the latter is a single duct, if the intake duct is arranged to penetrate the head pipe, there is a possibility that the required strength of the head pipe may not be ensured if the intake duct is arranged to penetrate the head pipe. is there. On the other hand, when the head pipe is detoured, the layout of the duct becomes asymmetric, which is not preferable in terms of design, and the resistance of the airflow at the detour part (bent portion) increases. In addition, if the air passage area is sufficiently secured even at the detour location, the layout of the peripheral components (main frame, fuel tank, etc.) must be changed or changed in shape because the outer shape of the duct becomes large. Occurs. Furthermore, since the front end opening of the air vent passage (the intake of the running wind pressure) is provided near the air intake of the intake duct, the surrounding area of the opening becomes negative pressure when a cross wind is received, and the float of the carburetor floats. The pressure balance between the chamber and the venturi may be lost.

[0007] The present invention has been made in view of the above-mentioned point, and guides outside air to an air cleaner by using two independent intake ducts from two air intakes.
Enough air passage area can be secured to enhance the ram air effect, and the layout is reasonable, and the two intake ducts are symmetrical and excellent in design, reducing intake noise.
It is another object of the present invention to provide an intake device for a vehicle engine in which a duct hole diameter can be reduced even when an intake duct is made to penetrate a main frame, and a necessary strength of the main frame can be secured.

Further, when ram air is introduced into the venturi portion of the carburetor, the upper space of the float chamber is pressurized through an air vent passage so as to balance the pressure between the venturi portion and the float chamber while receiving cross wind. Another object is to prevent the pressure balance from being lost.

[0009]

In order to achieve the above-mentioned object, an air intake device according to the present invention introduces outside air into a carburetor through an air cleaner using a traveling wind pressure, and uses the carburetor to mix an air-fuel mixture with fuel. in an intake device for a vehicle engine to be introduced into the combustion chamber, it is mounted on the vehicle body
Left and right across the center axis at the front of the fairing
Symmetrically, the pair of air intakes are on opposite sides when viewed from one side of the vehicle
The air intake of each air
Independent suction between the intake and the air suction port of the air cleaner
Connected by an air duct, and
Form the surging tank by expanding the middle part downward
The front end of the air vent tube is inserted into each of the air intakes.
The pressure around one of the openings decreases when a cross wind is applied to the opening
(Lower than the pressure when there is no cross wind)
The pressure around the opening increases (compared to the pressure when there is no crosswind)
The air vent.
Take out the tube from the middle of the intake duct,
Rear end in the upper space of the carburetor float chamber
It is communicated.

According to a second aspect of the present invention, the air vent tip is provided.
At the front end opening of the
Should be placed near the opening tip near the center of the
No.

According to a third aspect of the present invention, each intake air on the both sides is provided.
The duct can be formed integrally with the fairing.
I can .

[0012]

According to the intake device of the present invention having the above structure,
During traveling of the vehicle, outside air is introduced into the intake duct from the air intakes on both sides on the front side, and is guided to the air intake of the cleaner through the two intake ducts. The two intake ducts are completely independent, and the air passage area is sufficiently ensured, so that the intake noise is reduced and the ram air effect utilizing the traveling wind pressure is effectively exhibited. In addition, since the outer shape (diameter) of each intake duct can be made smaller than that of a single intake duct, the layout is reasonable and the duct hole diameter can be reduced even when the intake duct penetrates the main frame. Thus, it is easy to secure the necessary strength of the main frame.

Then, outside air is taken in from the front of the motorcycle.
If the temperature of the intake air to the engine drops,
In both cases, air from natural supercharging is introduced because the traveling wind is introduced.
The density is increased, and the output of the engine is improved. What
The pressure rise (△ ρ) due to the traveling wind is derived from the following equation.
Will be sent out. That is , Δρ = γ × V ² / 2g × 10 ^-4 where γ: Air density (kg / m ³ ) V: Running wind speed (km
/ h) In particular, by forming the left and right intake ducts symmetrically
Weight balance and excellent design
become. Ramair is a carburetor venturi
Carburetor through the air vent passage
Ram air pressure in the upper space in the floater chamber
Since it works, the venturi section and the float chamber
Is maintained constant, and an appropriate air-fuel ratio is obtained. Sa
In addition, the front end opening of the air vent passage is on both sides of the fairing.
Pressure around one opening when a crosswind is received in the air intake
So that the pressure around the other opening increases even if the force decreases
Because it is installed facing forward, the pressure around one opening
The force is reduced or reduced compared to the pressure when there is no crosswind
Negative pressure may occur around the other opening
Pressure is higher than when no crosswind is
Therefore , the pressure balance between the venturi section and the float chamber is always properly maintained. In particular, the front end opening of the air vent tube as described in claim 2 ,
An opening near the center of the vehicle body in each of the air intakes
If you place it near the edge, the float chamber
Internal pressure can be increased more effectively, and
It is much less susceptible to the effects of shaking .

According to a third aspect of the present invention, there is provided an air intake system.
By forming the shield integrally with the fairing,
Eliminates wasted space and is compact.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention applied to a motorcycle engine.

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 shown in FIG. 1, and FIG. FIG.
FIG. 4 is a side view of FIG.

As shown in FIG. 1, in a motorcycle A,
One end of a pair of main frames 2 constituting a part of the body frame is connected to both sides of the head pipe 1, and an engine 3 is mounted near a 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 from the rear end of the vehicle body frame via a pair of rear arms (not shown). A fuel tank 6 is disposed at the upper end of the body frame behind the head pipe 1,
The seat 7 is attached to the rear. A fairing 8 is mounted from the front of the vehicle body to the front half of both sides. In the drawing, reference numeral 9 denotes an air cleaner, reference numeral 10 denotes a carburetor, and a rear end of an intake duct 13 is connected to an air suction port 9a (FIG. 4) of the air cleaner 9 by a connection duct 1.
4 (FIG. 4).

As shown in FIG. 3, in front of the fairing 8, a pair of air intakes 12.1, symmetrically with respect to the center axis LL, on both sides of the headlight 11 in the center.
2 have been established. Then, as shown in FIG. 2, the two air intakes 12 on both sides and the air intake 9a of the air cleaner 9 are respectively independent symmetrical intake ducts 13.
13. Intake ducts 13 on both sides
13 has a bifurcated branch 14
a of the air cleaner 9 is connected to the front end of the air cleaner 9. The rear ends of the intake ducts 13 pass right above the main frame 2 or penetrate the main frame 2 and are led to the air inlet 9a of the air cleaner 9. In FIG. 2, reference numeral 15 denotes a handle shaft, and reference numeral 16 denotes a steering handle.

The intake duct 13 is provided as shown in FIG.
Surge tank 13a by inflating the middle part downward
Is formed. In the surging tank 13a, the flow velocity of the air passing through the duct 13 is reduced, and rainwater or the like entering the duct 13 from the air inlet 12 is separated from the air and stored in the surging tank 13a. And
The accumulated rainwater and the like are discharged from a drain (not shown) formed in the bottom of the surging tank 13a, and therefore do not enter the air cleaner 9. In addition, the intake duct 13 may be formed separately from the fairing 8 and attached to the inner wall of the fairing 8, but the intake duct 13 is formed as a part of the fairing 8.
Can also be formed integrally. Especially the intake duct 13
If it is formed integrally with the fairing 8, it can be made compact and no useless space is produced.

A front end opening 17a of an air vent tube (air vent passage) 17 is mounted in each of the air inlets 12 so as to face forward, and the air vent tube 17 is taken out of the intake duct 13 as shown in FIG. FIG.
The rear end communicates with the upper space of the float chamber 10a of the carburetor 10 as shown in FIG. Engine 3
When the FIG. 1 includes a plurality of cylinders (for example, four cylinders) and a plurality of carburetors 10 corresponding to the number of cylinders, the left and right air vent tubes 17 are assembled from the middle.
To make one, then branch to the carburetor of each cylinder
It is good to communicate with each other .

[0021]

According to the intake system of the present embodiment having the above-described configuration, when the motorcycle A travels, the outside air is supercharged by the traveling wind pressure, and the ram air is supplied to the two intake ports from the air intake ports 12 on both sides. Air cleaner 9 through ducts 13
Will be introduced. And this ram air is carburetor 1
0 is sent to the 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 openings 17a of the air vent tubes 17 provided in each air intake port 12. . Thereby, the venturi section 10b and the float chamber 1
The pressure difference from 0a is kept constant, and an appropriate air-fuel ratio is obtained.

The above embodiment is applied to a motorcycle engine.
Although not limited to motorcycle engines,
Needless to say, it can be applied to engines such as moving vehicles.
No.

[0024]

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

(1) Align the center axis on the front of the fairing
The air intake on the opposite side when viewed from one side of the vehicle body symmetrically across
Two independent air intake ducts are used to guide the outside air to the air cleaner from the two air intakes that are spaced apart so that the entrance is hidden, so there is enough air passage area to enhance the ram air effect. It can be secured, and it is reasonable from the layout. In addition, the intake noise can be reduced, and the diameter of the duct hole can be reduced even when the intake duct penetrates the main frame, so that the required strength of the main frame can be secured. In addition, the front end opening of the air vent passage is fair
When a crosswind is received in the air intake on both sides of the ring,
Even if the pressure around the opening is lower than when there is no crosswind
The pressure around the other opening is higher than when there is no crosswind
To the front so that the vent
The pressure balance between the lead section and the float chamber is lost
Hard .

(2) The venturi section of the carburetor
When introducing ram air into the upper part of the float chamber
The space was pressurized through the air vent passage
In, the pressure rose to the base Nchuri portion and the float chamber
And a proper air-fuel ratio can be obtained . The left and right
If the intake duct is formed symmetrically ,
And the design is even better.

(3) In the air intake system according to the second aspect, the air intake device is
Insert the front end opening of the vent tube into each of the above air intakes.
Because it was placed near the opening tip near the center of the car body,
More effectively increase the pressure in the float chamber when driving
And the effects of crosswinds
Can be smaller .

(4) In the intake device according to the third aspect, each intake air
Since the duct is formed integrally with the fairing,
There is no pace, and it is compact.

[Brief description of the drawings]

FIG. 1 is a side view showing an outline of a motorcycle provided with 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 of FIG. 1;

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

FIG. 4 is a side view of FIG. 2 with a part shown in cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head pipe 2 Main frame 3 Engine 8 Fairing 9 Air cleaner 10 Carburetor 12 Air inlet 13 Intake duct 17 Air vent tube (air vent passage) A Motorcycle

Claims (3)

(57) [Claims] 1. A were introduced into the carburetor through the use of traveling wind pressure outside air cleaner, the intake system of a vehicle engine for introducing air-fuel mixture mixed with the fuel in the carburetor to the combustion chamber, it is mounted on the vehicle body Fair Its center at the front of the ring
A pair of air intakes is symmetrically placed on one side of the vehicle body with respect to the axis.
Make sure that the air intake on the opposite side is
The air inlet and the air inlet of the air cleaner are independent.
Connected with the intake duct
Inflating the middle part of
Forming and opening a front end of an air vent tube in each of the air inlets;
When the pressure around one of the openings drops
Take forward so that the pressure around the other opening increases.
And attach the air vent tube in the middle of the intake duct.
The carburetor float
An intake device for a vehicle engine, wherein the intake device communicates with a space above a member . 2. A front end opening of the air vent tube,
An opening near the center of the vehicle body in each of the air intakes
The intake device for a vehicle engine according to claim 1, wherein the intake device is disposed near an end . 3. Each of the intake ducts on both sides is connected to the fair
3. The intake device for a vehicle engine according to claim 1, wherein the intake device is formed integrally with the ring .