JPS6017266A - Fuel injection system for internal-combustion engine - Google Patents

Abstract

PURPOSE:To carry out highly excellent atomization and improve both the fuel consumption at the time of low load and the stability of an engine by guiding fuel which flows down on the inner wall surface of a suction air passage, to a throttle valve totally closing position or to the lower course of said throttle valve. CONSTITUTION:Fuel deposited as a liquid drop on the inner wall surface of a suction air passage 15 at the time of low load is caught in a fuel guide groove 16 and pushed to flow by means of the current of suction air, thereby being gathered at a lower course part 16a. On the other hand, when a throttle valve 13 is almost totally closed as at the time of idling, since suction air passes through a slight gap between the throttle valve 13 and the inner wall surface of the suction air passage at a speed close to sonic velocity, a large negative pressure is generated near the end of opening 17b of an auxiliary suction air passage 17, thereby sucking off the fuel gathered in the lower course part 16a together with suction air flowing through the auxiliary suction air passage 17. And, by colliding against a high speed suction air current, the fuel is atomized in a good condition. At the time of low loading, a relatively large suction load acts on the end of opening 17b, securing good atomization.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a fuel injection device for an internal combustion engine that performs concentrated fuel injection at a position upstream of a throttle valve.

As a fuel injection device for an internal combustion engine having multiple cylinders, for example, as shown in Fig. There is a configuration in which an injection valve 3 is arranged to centrally inject fuel, and the air-fuel mixture formed here is distributed to various portions on the downstream side of the throttle valve 2 (% Kaimei No. 57-75858). Public notices, etc.).

According to this, compared to a fuel injection device of the type in which one fuel injection valve is provided in the intake valve of each cylinder, the configuration is low in cost due to the volumetric water consumption, and on the other hand, the air-fuel ratio is lower than in the case of using a carburetor. 3M has an advantage in terms of control (ill 1),
There are advantages such as

However, when fuel injection is carried out intensively in this manner, the fuel injection valve 3 used is one with a relatively large capacity so as to sufficiently cover the required fuel volume at high speed and high load. However, when there is little fuel injection, such as during idling or low load, atomization is poor and most of the injected fuel turns into droplets and flows down the inner wall of the intake passage. This caused deterioration of engine stability and fuel efficiency, etc.

This invention was made in view of the above-mentioned conventional j value, and it is possible to sufficiently atomize the fuel even under low load with a small amount of fuel supply.
The aim is to improve fuel efficiency and engine stability at low loads, which have been problems with fuel injection systems.

That is, the fuel injection device a for an internal combustion engine according to the present invention includes a fuel injection valve provided upstream of the throttle valve IU of the intake passage, and an inner wall of the intake passage between the fuel injection valve and the throttle valve.
A fuel guide groove formed at a slight angle with respect to a plane orthogonal to the intake passage, one end of which opens downstream of the fuel guide groove, and the other end of which opens at a fully closed throttle valve position or a downstream position of the throttle valve.
The fuel guide groove captures fuel droplets that are about to flow down the intake passage inner wall IJii, and directs the captured fuel to the fully closed position or throttle position. By sucking it out downstream of the valve, extremely good atomization can be achieved.

Hereinafter, a specific embodiment of the present invention will be described in detail based on the drawings.

FIG. 2 shows an injection body 11 having a built-in fuel injection device according to the present invention at 74'. The lower half 11b is integrated with a heat insulating gasket 14, and has an intake passage 15 in the vertical direction, the upper end of which is connected to an air cleaner (not shown), and the lower end of which is connected to an air cleaner (not shown). They are respectively connected to an intake manifold (not shown). The fuel injection valve 12 located upstream of the upper self-throttle valve 13 is supported from the side so as to project into the intake passage 15.
The lower end nozzle 12 a is directed toward the throttle valve 13 . Incidentally, this fuel injection valve 13 has a relatively large discharge capacity, and usually one or two fuel injection valves are provided.

On the other hand, a circumferentially continuous fuel guide groove 16 is recessed in the inner wall surface of the intake passage 15 of the lower injection body portion 11 b at a position slightly upstream of the throttle valve 13 . This fuel guide groove 16 is slightly inclined with respect to the orthogonal surface of the intake passage 15, and due to this inclination, one end 17a of the auxiliary intake passage F is located at a downstream portion 16a on the right side in the figure, which is relatively downstream. is open. The opening end 17a of the auxiliary intake passage 17 is inclined so that the fuel captured by the fuel guide groove 16 can easily flow in, and the downstream side G'i #17b is a throttle valve. It opens at the fully closed position of 13. Further, in this embodiment, the opening end 1
7 b is the throttle valve 1 that moves to the upstream side when the N throttle valve 13 opens.
Accordingly, the upper fuel guide groove 16 also has an inclined shape with the right side in the figure lowering toward the downstream side.

Now, according to the above-described configuration, when the engine is placed at a low position, the fuel adhering to the inner wall surface of the intake passage 15 in the form of droplets is captured by the fuel guide groove 16 as it flows downstream.
In addition, as a result of being pushed by the intake air flow and flowing along the slope, it is collected in the downstream portion 16a. On the other hand, when the throttle valve 13 is in a substantially fully closed state such as when idling, the intake air passes through the small gap 11n between the throttle valve 13 and the inside of the intake passage 15 at a speed close to the speed of sound. A large negative pressure is generated near the open end 17b of the fuel guide fil as described above.
The fuel collected in the downstream part 16a of the fuel pump 16 is sucked out together with the intake air flowing through the auxiliary intake passage 17, and here it is very well atomized by impinging on the 1% speed intake υIL. Also, in the low load state ζ when the throttle valve 13 is wide open, the opening end 17 of the auxiliary intake passage 17 is
A relatively large suction negative pressure acts on b, and similarly good atomization can be ensured.

As described above, by improving fuel atomization during low engine load, it is possible to improve engine stability, fuel efficiency, and lean limit. Figure 6 shows the fuel monitor 'R,k at idle.
It is a characteristic diagram showing the relationship between ft and suction negative pressure and the engine stability under each condition. Specifically, it is a characteristic diagram showing the relationship between ft and suction negative pressure and the engine stability under each condition.
The suction negative pressure was measured and plotted (○・
・Conventional, △・This example), and at the same time, the stability evaluation at that time is written in the valley plot symbol. In addition, this stability l (is evaluated on a scale of 1 to 707, the larger the number, the better the stability, and the evaluation "4" or higher is the practical ijJ.
It is within the scope of ability. As is clear from FIG. 6, this embodiment shown by the dotted line can significantly reduce fuel consumption compared to the conventional one shown by the solid line, and has a stability level of "4".
The above areas can be expanded.

Next, in the embodiment shown in FIG.
The other end Z7 of the auxiliary intake passage 17 where 14j17a is opened
b is opened at a downstream position of the throttle valve 13. In this case, the fuel is sucked out by the developed suction negative pressure downstream of the throttle valve 13 during idle or low load, and this negative pressure causes it to rapidly expand and diffuse at the opening end 17b, similar to the above embodiment. Good atomization is achieved.

Next, the embodiment shown in FIG. 5 is 1111 auxiliary intake passage 1.
When the throttle valve L3 is in the fully closed position, the downstream opening end 17b of the throttle valve 13 moves downstream 1tllll when the throttle valve 13 is opened. Downstream end Ipe 1
3b, and accordingly, the fuel guide groove 16 is formed in an inclined state with the left side of the figure downward toward the downstream side.

According to this embodiment, as the opening of the throttle valve 13 increases [1, the opening end 1.7b moves to Tsuchiura, which is 411 opposite to the throttle valve 13, so that the opening of the throttle valve 13 increases to a certain degree. At this point, the fuel sucked out from the auxiliary intake passage F is increased to f7P+L, thereby avoiding deterioration of fuel responsiveness during medium and high loads.

In addition, in the embodiment shown in FIG. 5, the opening end 17b may be formed slightly further downstream as shown by the dotted line.
'It is Noh.

Further, each of the above embodiments is provided with one fuel guide groove 16, but a plurality of fuel guides @ 16, for example, two fuel guide grooves are provided.
The fuel guide grooves 16 may be provided substantially in parallel in multiple stages, or may be provided so as to intersect with each other.Furthermore, the fuel guide grooves 16 do not necessarily have to be formed over the entire circumference; The position and its +J 'iL4 angle
Portions where the fuel does not flow due to the ν1 coefficient can be omitted.

As is clear from the above description, in the fuel injection device for an internal combustion engine according to the present invention, it is possible to guide the waste material that υ1 on the inner wall surface of the intake passage during low load to the fully closed position of the throttle valve or downstream of the ribbon valve. As a result, it is possible to perform a very good samurai conversion, and compared to the conventional fuel injection method, it is possible to improve fuel efficiency and opening stability at low loads.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a sectional view showing one 191J of the fuel injection device from FIT, Fig. 2 is an F@ side view showing an example of this invention, and Fig. 5 is a fuel injection device at idle. 4 and 5 are sectional views showing different embodiments of the present invention, respectively. 11...Injection body, 12...Fuel injection claw 13...Single valve, 15...Intake passage, 16...
Fuel F1 guide groove, 17...auxiliary intake passage. Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] (1) A fuel injection valve provided upstream of the throttle valve in the intake passage, and an inner wall surface of the intake passage between the fuel injection valve and the throttle valve,
A fuel guide groove formed at a slight angle with respect to a plane orthogonal to the intake passage, one end of which opens downstream of the fuel guide groove, and the other end of which opens at a throttle valve fully closed position or a throttle valve closed position. A fuel injection device for an internal combustion engine, comprising an auxiliary intake passage.