JPS649466B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection type carburetor, and more particularly to a fuel injection type carburetor in a multi-cylinder internal combustion engine.

In a multi-cylinder gasoline-injected internal combustion engine, one fuel injection valve is provided for each cylinder in the intake manifold near the intake port, and fuel is injected from each fuel injection valve into the intake port of the corresponding cylinder. A fuel injection type carburetor that injects fuel has already been proposed. Although this type of fuel injection carburetor has the advantage of equalizing the amount of fuel supplied to each cylinder, it not only does not sufficiently atomize the fuel supplied into the combustion chamber, but also has the advantage of equalizing the amount of fuel supplied to each cylinder. There is a problem that an injection valve is required.

In order to solve these problems, a fuel injection carburetor was proposed in which a single fuel injection valve was installed in the gathering part of the intake manifold, and the fuel injected from this fuel injection valve was distributed to each cylinder. has been done.
In this type of fuel injection type carburetor, the amount of fuel required for each combustion in the combustion chamber of each cylinder is intermittently injected from a fuel injection valve in synchronization with the opening/closing timing of the intake valve of each cylinder. It is desirable to electronically control the fuel injection valves so that all of the fuel injected each time is sequentially supplied to the combustion chamber of a predetermined cylinder. This makes it possible to equalize the amount of fuel supplied to each cylinder.

However, in this type of fuel injection carburetor, fuel atomization and atomization characteristics are greatly affected by slight differences in the mounting position and injection direction of the fuel injector, the shape of the throttle valve, etc. It is also affected by the uniformity of the amount of fuel distributed to each cylinder. In addition, if a throttle bore that extends vertically is connected to an intake manifold that extends approximately horizontally, the flow of intake air will be forcibly bent near the gathering part of the intake manifold, resulting in less injected air. There is also the problem that the fuel jet does not fully ride the air flow and adheres to the inner wall of the intake manifold, deteriorating the atomization characteristics.

The present invention was devised to solve these problems, and in particular, by improving the flow characteristics of intake air, it prevents fuel from adhering to the intake manifold wall, and prevents fuel atomization. It is an object of the present invention to provide a fuel injection type carburetor that has good atomization characteristics and uniformizes the distribution of fuel to each cylinder.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 2, an intake manifold 2 is fixed to a main body 1 of a multi-cylinder internal combustion engine. As is clear from FIG. 2, the intake manifolds 2 extend substantially horizontally, and the manifolds are assembled at a gathering portion 3. A substantially vertical manifold flange 4 is provided integrally with the intake manifold 2 at the right end of the intake manifold gathering portion 3 . The substantially cylindrical throttle body 5 has a mounting flange 6 integrally formed at its left end, and has a cylindrical throttle bore 7 extending horizontally and having a substantially uniform cross section formed therein. As is clear from FIG. 2, the mounting flange 6 of the throttle body 5 is fixed to the manifold flange 4 via a gasket 8. Thus, the throttle bore 7 communicates with the intake manifold assembly 3 and extends horizontally to the right from there. Note that the reference numeral 19 in FIG. 1 indicates an air cleaner.

At the left end of the throttle body 5, a thin cylindrical extension part 9 that projects into the space of the intake manifold gathering part 3 is formed integrally with the throttle body 5. As shown in FIG. 2, the end edge 10 of this extension part 9 is formed in the shape of a knife edge that points inward. It is arranged as follows. In the embodiment shown in FIG. 2, the end edge 10 of the thin-walled cylindrical extension 9 is pointed inward, but it may be formed into a knife edge shape that is pointed outward.

A riser heating cavity 31 is formed inside the lower wall 30 of the intake manifold collecting section 3 . Although not shown, the cavity 31 is configured so that a portion of the exhaust gas is introduced into the cavity, and the exhaust gas preheats the intake air to promote vaporization of the fuel. This improves the warm-up characteristics of an internal combustion engine. When a riser heating cavity 31 as shown in FIG. 2 is provided, it is desirable that as much intake air as possible comes into contact with this portion. It is preferable to cut the extension part 9 diagonally as shown by the dotted chain line 10' and shorten the extension part 9 below the intake manifold collection part or riser part 3.

In FIG. 2, a throttle shaft 11 is provided in the throttle bore 7.
A throttle valve 12 in the form of a butterfly valve is fixed to. The throttle shaft 11 extends substantially horizontally in a direction substantially perpendicular to the direction of air flow within the throttle bore 7, that is, perpendicular to the central axis of the throttle bore 7. Throttle valve 1
2 has a valve half body 12a on the left side in FIG. 2 extending toward the engine body side, that is, the intake manifold side with respect to the throttle shaft 11, and a valve half body 12b on the right side in FIG. 2 extending on the opposite side. The throttle shaft 11 of the throttle valve 12 is connected to an accelerator pedal in the driver's cab of the vehicle (not shown), and when the accelerator pedal is depressed, the throttle valve 12 rotates clockwise in FIG. 2 to open the passage of the throttle bore 7 ( Fig. 2 solid line position). Further, when the accelerator pedal is released, the throttle valve 12 rotates counterclockwise in FIG. 2 to close the passage of the throttle bore 7 (second
Figure (dashed line position).

A linear injection type fuel injection valve 1 is mounted on the lower wall of the throttle body 5 so as to inject fuel diagonally downstream from the bottom to the top on the left side or downstream of the throttle valve 12 in the throttle bore 7.
3 is installed. That is, as shown in FIG. 2, the fuel injection port 14 of the fuel injection valve 13 is oriented obliquely upward and to the left.

To explain the relationship between the fuel injection valve 13 and the throttle valve 12 in more detail, when the throttle valve 12 opens, the throttle valve 12 with respect to the throttle shaft 11
The left half 12a of the fuel injection valve 13 rotates upward in the forward direction relative to the fuel injection direction of the fuel injection valve 13. Further, when the throttle valve 12 reaches the fully open position (solid line position in FIG. 2), the fuel jet from the fuel injection port 14 of the fuel injection valve 13 hits the left half 12a of the throttle valve 12. For this reason, the fuel injection port 1 when the throttle valve 12 is in the fully open position
The mounting position and mounting angle of the fuel injection valve 13 are set so that the distance l from the intersection of the center axis 15 of the engine 4 and the throttle valve 12 to the throttle shaft 11 is 1/2 or less of the inner diameter D of the throttle bore 7.

As described above, the fuel injection valve 13 is a linear injection type fuel injection valve, and the fuel jet is injected from the fuel injection port 14 of the fuel injection valve 13 in a substantially straight line. Creates a swirling flow inside the fuel injector at 60 degrees or more
The structure is simpler than the so-called swirl-type fuel injection valve, which injects fuel at an injection angle of 120 degrees. Since this type of straight-line fuel injection valve itself has been conventionally known, a detailed explanation of its structure is not necessary.

The fuel system to the fuel injection valve 13 is connected to the fuel tank 2.
0 is supplied to the fuel injection valve 13 by the pump 21 through the fuel conduit 22, and the electrical system of the fuel injection valve 13 is connected to the control voltage from the electronic control unit 23 through the connector 24. transmitted to. Thereby, the fuel injection valve 13 intermittently injects the amount of fuel necessary for each combustion in the combustion chamber of each cylinder from the fuel injection port 14 in synchronization with the opening/closing timing of the intake valve of each cylinder. Reference numeral 25 denotes a pressure regulator that controls the amount of fuel returned by intake pipe negative pressure.

In FIG. 2, the throttle valve 12 rotates clockwise as indicated by the arrow in the figure from fully closed to fully open. As is clear from the figure, the fuel jet injected from the injection port 14 of the fuel injection valve 13 hits the left half 12b of the throttle valve 12 from a medium load range to a high load range where the opening degree of the throttle valve 12 is relatively large. This atomizes the injected fuel and promotes atomization. A part of the atomized fuel hits the extension part 9 before flowing into the intake manifold collecting part 3 and mixes with the fuel moving to the left while adhering to the inner wall surface of the throttle bore 7 at the knife edge-shaped edge 10 of the extension part 9. It is sheared by the airflow, further promoting atomization of the fuel. Also,
In a low load range where the opening degree of the throttle valve 12 is small, the fuel jet injected from the injection port 14 of the fuel injection valve 13 has a high negative pressure in the intake pipe, and this high negative pressure improves atomization of the fuel. A portion of the fuel directly hits the extension 9 and is sheared by the air mixture at the knife edge 9, promoting atomization of the fuel. In addition, particularly in the low to medium load range, the flow velocity of the air flowing between the left valve body 12a of the throttle valve 12 and the inner wall surface of the throttle bore 7, that is, the lower side, is higher than the flow velocity of the air flowing on the opposite side, that is, the upper side. Moreover, arranging the injection port 14 of the fuel injection valve 13 on the lower side where the air flow rate is high also helps in atomizing the injected fuel.

In this embodiment, since the throttle bore 7 extends horizontally and the intake manifold 2 also extends horizontally, the air-fuel mixture that has flowed from the throttle bore 7 to the intake manifold collecting section 3 flows easily to a predetermined intake manifold 2. Inflow. Further, in the present invention, a linear injection type fuel injection valve 13 is used, and since this is installed on the lower wall of the throttle bore 7 and injects fuel diagonally upward, the injected fuel The jet is the throttle valve 12
Even in a light load range where the fuel does not reach the upper wall of the throttle bore 7, most of the fuel is atomized by the time it reaches the upper wall of the throttle bore 7 due to the high intake pipe negative pressure at that time. Further, the adhesion of fuel to the wall surface of the intake manifold 2 is reduced. In that case, when the air-fuel mixture flows through the intake manifold collection section 3, it is heated by the riser heating cavity section 31 provided inside the lower wall section 30 thereof. This promotes vaporization of the fuel. In order to heat the air-fuel mixture more effectively, it is desirable that the thin cylindrical extension 9 be cut along the dashed dotted line 10' as described above. Thereby, the area of the air-fuel mixture heating region can be increased.

As described above, in the present invention, the intake manifold and the throttle bore are made approximately horizontal, and the injected fuel from the fuel injection valve arranged from the bottom to the top in the downstream area of the throttle valve collides with the throttle valve when the throttle valve is fully opened. As a result, in medium to high load ranges, the injected fuel collides with the throttle valve, resulting in good fuel atomization, and at low loads, the intake pipe negative pressure becomes high, resulting in improved atomization. Since the atomization of the fuel is improved and the atomization flow of the air-fuel mixture is smooth, the amount of fuel supplied to each cylinder is also made uniform.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a part of a multi-cylinder internal combustion engine, and FIG. 2 is an enlarged sectional view taken along the line - in FIG. 1, showing an embodiment of the fuel injection type carburetor of the present invention. It is something. 2... Intake manifold, 3... Intake manifold gathering part, 7... Throttle bore, 9... Extension part, 10... Edge knife edge, 12... Throttle valve, 13... Fuel injection valve, 14... Fuel injection port.

Claims (1)

[Claims] 1 Connect the throttle bore extending substantially horizontally to the gathering part of the intake manifold extending substantially horizontally,
A throttle valve is attached so as to be openable and closable to a substantially horizontal throttle shaft extending in a direction generally perpendicular to the direction of air flow in the throttle bore, and fuel is distributed diagonally downstream from below to above in the downstream region of the throttle valve. A fuel injection system for a multi-cylinder internal combustion engine, characterized in that a fuel injection valve is arranged on a lower wall of a throttle bore so as to inject the fuel at a maximum speed, and the fuel injected from the fuel injection valve collides with the throttle valve when the throttle valve is fully opened. Expression naturalizer.