JPS5933885Y2 - Internal combustion engine fuel supply system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply device for an internal combustion engine that includes a fuel supply nozzle provided in an intake passage downstream of a throttle valve.

As a conventional fuel supply device of this kind, there is one shown in FIG. 1, for example (see Japanese Patent Laid-Open No. 54124118).

This example is of a so-called single point injection system (few injection system).

That is, a throttle valve 4 is provided in an intake passage 3 that connects the clean side of the air cleaner 1 and the gathering portion of the intake manifold 2.

Further, a reflector plate 5 is attached to the center of the intake passage 3 downstream of the throttle valve 4, and a nozzle 6 injects fuel toward the reflector plate 5.
A fuel injection valve I having a fuel injection valve I is attached to a throttle body 8 forming the passage 3.

Then, by communicating the inside of the air guide 9 covering the tip of the nozzle 6 (the gap surrounding the nozzle) with the upstream side of the throttle valve 4 via the air passage 10, the air introduced into the area around the nozzle 6 is Atomization of the fuel ejected from the nozzle 6 was promoted with air.

11 is a filter element of the air cleaner 1; 12 is a small Karman sensor as an air flow meter built into the clean side of the air cleaner 1; 13 is a fuel injection valve 7Tf - a pressure regulator that controls the pressure of the fuel being fed 1; 14 is an air regulator for increasing the air flow rate during warm-up and startup.

In such a configuration, from the nozzle 6 of the fuel injection valve 7, an amount of fuel corresponding to the intake air amount of the engine is injected and supplied toward the reflector plate 5, and the throttle valve 4 is bypassed around the nozzle 6. Air is introduced from the air passage 10.

For this reason, the fuel ejected from the nozzle 6 flows out from the air guide 9 together with the air introduced as described above, thereby promoting atomization of the fuel.

However, if the flow rate of air bypassing the throttle valve 4 is greater than the required intake air amount in the idle link state, the idle link rotational speed cannot be controlled. That is, the idle link rotational speed was adjusted by providing a needle valve 15 at the air intake port.

Note that during idle link, the throttle valve 4 is almost completely closed in order to mainly supply air from the air passage 10.

However, when the air flow rate is adjusted at the air intake, the air flow velocity reaches its maximum near that area.

For this reason, the flow velocity of the introduced air is not maximum in the vicinity of the nozzle, which is most important in atomizing the fuel by introducing air, so there is a problem that the effect of atomizing the heating charge by introducing air cannot be utilized to its fullest extent.

The present invention has been developed in view of the above, and by changing the position of the nozzle to change the gap (passage area) of the air passage formed around the nozzle, fine fuel particles flowing down from the upstream of the throttle valve can be reduced. The purpose is to adjust the amount of promoting air to maximize the flow velocity of the air near the nozzle, thereby maximizing the atomization effect of the fuel.

The present invention will be described below with reference to an embodiment shown in FIG.

In the figure, the clean side of an air cleaner 21 that accommodates a filter element 20 is communicated with a gathering part of an intake manifold 22 of the engine via an intake passage 24 formed in a throttle body 23.

A throttle valve 25 connected to an accelerator pedal (not shown) via a control lever and an accelerator link (not shown) is attached to the intake passage 24, and the throttle valve 25
A reflector plate 26 is mounted approximately at the center of the intake passage 24 downstream of the intake passage 24.

Further, a fuel injection valve 30 having a nozzle 29 directed toward the reflection plate 26 is attached to the throttle body 23 and the holder portion 2B of the pressure regulator 27 fixed to the body 23 so as to be movable in the axial direction, and the fuel injection valve 30 is mounted so as to be movable in the axial direction. An adjusting screw 31 screwed into the valve 30 is brought into contact with the outer surface of the throttle body 23.

And between the holder 28 and the fuel injection valve 30,
A spring 32 that urges the injection valve 30 toward the throttle body 23 is tensioned to hold the adjustment screw 31 in contact with the throttle body 23.

That is, the adjustment screw 31 and the spring 32 control the fuel injection valve 3.
0 constitutes a position adjustment mechanism.

33 is a spring for fixing the adjustment screw 31, and 34.35 is the fuel injection valve 30, throttle body 23, and holder 2B.
This is an O-ring inserted between the

On the other hand, an air passage 36 for introducing air from upstream of the throttle valve 25 around the nozzle 29 is connected to the throttle body 23.
However, the passage area of the passage 36 has a cross-sectional area with sufficient margin so that the maximum air flow rate can be adjusted by moving the fuel injection valve 30 equipped with the nozzle 29 toward and away from the air guide 37. do.

38 is an air regulator that increases the air flow rate during startup and warm-up; 39 is a small Kalman sensor as an air flow meter built into the clean side of the air cleaner 21; and 40 is a fuel injection valve 30 that shapes the Kalman waveform. 42 is a power source, 43 is a crank angle signal that is input as an injection timing signal to the control circuit 41, and 44 is a spring for fixing the air guide.

With the above configuration, a part of the air that has passed through the filter element 20 of the air cleaner 21 passes through the small Karman sensor 39 and is input to the control circuit 41 via the waveform shaping circuit 40 as a representative value of the intake air amount of the engine. be done.

Further, the control circuit 41 uses the air flow rate signal and crank angle signal 43 input as described above to control the fuel injection valve 30.
By controlling the time ratio when the valve is turned on, fuel is injected at a flow rate that matches the intake air flow rate from the nozzle 29 of the injection valve 30 to the downstream side of the throttle valve 25.

The fuel ejected from the nozzle 29 mixes vigorously with the air introduced around the nozzle 29 from upstream of the throttle valve 25 via the air passage 36, becomes atomized, and is sent to the reflector plate 26 via the air guide 31. It is squirted towards you.

At this time, the flow rate of air introduced into the space surrounding the nozzle 29 is determined by the distance between the nozzle 29 and the air guide 37, that is,
Since it is controlled by changing the position of the fuel injection valve 30, the flow velocity of this air is maximum around the nozzle 29.

Therefore, the effect of atomizing the fuel by introducing air is maximized.

The distance between the nozzle 29 and the air guide 3T, that is, the flow rate of air introduced into the space around the nozzle 29, is determined by adjusting the adjustment screw 31 when adjusting the idle link rotation speed during factory production or during inspection and maintenance. Proper adjustment is made by adjusting the screw advance and retreat.

If the opening degree of the throttle valve 25 is almost fully closed during such idle link adjustment, idle link adjustment can be performed at the position of the fuel injection valve 30, and at the time of idle link, almost the entire intake air of the engine is removed from the fuel particles. It can be used for

For this reason, the fuel can be sufficiently atomized even during idling, and it is also easier to adjust the intake air flow rate, which requires extremely delicate adjustment, making it possible to stabilize the idling rotation speed and simplify the adjustment work. Facilitated.

In the embodiment, a case of a so-called single point injection system has been described, but in addition to the fuel injection valve, a fuel injection valve may be provided in the intake port of each cylinder or in the intake manifold branch part, and the injection valve The control mechanism for is arbitrary.

As explained above, according to the present invention, the position of the nozzle from which fuel is ejected can be adjusted to adjust the flow rate of the fuel atomization air introduced into the gap around the nozzle. The flow velocity of air around the nozzle can be maximized, and the amount of air can also be maximized.

Therefore, in order for the fuel to be atomized consistently and well,
It is possible to improve stabilization of the air-fuel ratio during transient operation, and to reduce fluctuations in the air-fuel ratio during steady operation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an example of a conventional device, and FIG. 2 is a sectional view of a main part showing an embodiment of the present invention. 24...Intake record, 25...-Comparison valve, 29.
... Nose 30 ... Fuel injection valve, 31
...adjustment screw, 32...spring,
36...Air passage, 37...Air guide.

Claims (1)

[Scope of utility model registration request] A fuel supply nozzle provided in an intake passage downstream of the throttle valve, and an air passage communicating through a gap around the nozzle and bypassing the air passage from upstream to downstream of the throttle valve, and through the air passage. In a fuel supply device for an internal combustion engine that promotes atomization of fuel ejected from the nozzle with air guided around the nozzle, the nozzle is movably mounted, and the movement of the nozzle causes air to flow near the nozzle. A fuel supply device for an internal combustion engine, characterized in that the area of a passage can be changed.