JPS60252164A - Solenoid-controlled type fuel injection valve - Google Patents

Abstract

PURPOSE:To aim at prevention against drops of fuel and improvements in an injection effect, by making up a lower end form of a swirl bar into a conical form. CONSTITUTION:A tip part of a swirl bar 12 is made up into an inversed conical form of a tip angle theta. In case of constitution of the conventional examples, a passage area has been largely varied at a C position of a lower end of the swirl bar 12. This means that it was a main factor to suddenly change a fuel flow velocity, causing the generation of a swirl. In constant this, in case of the invention, the passage area is so constituted as to be varied so uniformly whereby the generation of the swirl is checkable in design, and since it is an inversed conical form, even if fuel is stuck to it, it droppable down before growing large, thus favorable atomization is securable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to electromagnetic fuel injection valves used in engines of automobiles, etc., and in particular, to prevention of fuel dripping.

This invention relates to an electromagnetic fuel injection valve that improves spray performance.

[Background of the invention]

Electronic engine control is progressing in response to stricter exhaust gas regulations and improved fuel economy.

There are multi-point fuel injection devices (MPI) and single-point fuel injection devices (SPI) that correspond to such systems.

MPI is expensive because a fuel injection valve is provided for each cylinder and fuel injection pressure must be increased. In contrast, SPI requires only one or two fuel injection valves to be installed in the intake pipe assembly, and since these fuel injection valves are placed upstream of the nine throttle valves, the fuel injection pressure can be lowered. The use of fuel pumps is increasing due to the fact that it is possible to reduce the cost of fuel pumps, piping, etc.

FIG. 1 is a sectional view of a conventional electromagnetic fuel injection valve used in this SPI. In FIG. 1, 1 is a fuel injection valve;
2 is a fixed core, 3 is a yoke, 4 is an exciting coil, and 5 is a plunger that functions as a movable core.
．． 5, a magnetic circuit is formed. The plunger 5, plunger rod 14, and ball valve 6 are integrally connected by welding and caulking to form a movable valve. When current is applied to the excitation coil 4, the plunger 5 is attracted toward the end surface of the fixed iron core 2, and moves upward in the figure until the upper end surface of the sliding portion of the plunger rod 14 comes into contact with the stopper 7. Since the ball valve 6 is integral with the plunger 5, an annular fuel passage is formed between the ball valve 6 and the valve seat 15 due to the above movement. When the excitation coil 4 is de-energized, the movable valve is returned to its original position by the spring force of the return spring 8 provided between the fixed iron core 2 and the plunger 5, and the space between the ball valve 6 and the valve seat 15 is returned to its original position. The annular fuel passage formed in the above is closed.

After being filtered by the filter 9, the fuel passes through the fuel port 10 and flows into the annular fuel passage described above. This fuel is given a swirling force when passing through the plurality of diagonal holes arranged in the swirl orifice 11, and is ejected through the opening of the nozzle 13 while making a swirling motion. The swirl bar 12 integrally attached to the swirl orifice is effective in preventing a reduction in swirling force due to entrainment of fuel within the nozzle 13.

When the fuel injection valve 1 is attached to the SPI described above and operated, its driving frequency is controlled in synchronization with the engine speed, and the injection pulse width is controlled in accordance with the operating state.

Here, since this fuel injection valve 1 is arranged upstream of the throttle valve, (1) uniform spray spread! D. (2) It is necessary to stabilize engine performance by preventing fuel dripping and uniformly supplying fuel to the annular intake passage formed by the throttle valve and the intake cylinder.

FIG. 2 shows the state of fuel spray in the prior art (see Japanese Unexamined Patent Publication No. 57-51943). The fuel is given a swirling force by the swirl orifice 11, and while performing a swirling motion along the inner wall of the nozzle 13, the fuel is ejected with approximately the same width as the widening angle of the conical portion of the nozzle 13. However, some of the fuel adheres to the lower end surface as shown in the figure due to the thinness generated at the lower end of the swirl bar 12, and when it grows to a size that overcomes the adhesion force due to the surface tension of the fuel, it drips over the swirl bar 12. This will cause inconvenience. In other words, since these fuel particles drop onto the throttle valve, they are hardly atomized and are supplied into the intake passage, causing the mixture to become temporarily rich.
This caused spikes in CO in the exhaust gas, deterioration of engine performance, etc.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electromagnetic fuel injection valve that eliminates the above-mentioned disadvantages of the prior art, prevents dripping of fuel, and improves spraying.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized by a swirl orifice having a plurality of diagonal passages, an integrated swirl bar, and an inner surface on the swirl orifice side having a cylindrical shape and a truncated conical shape on the fuel outlet side. In the electromagnetic fuel injection valve equipped with a nozzle, the lower end of the swirl bar is configured to have a conical shape with an apex at the bottom.

[Embodiments of the invention]

An embodiment of the present invention will be explained with reference to the sectional view shown in FIG. The tip of the swirl bar 12 is formed into an inverted conical shape with a tip angle θ. Figure 4 shows the swirl orifice 11.
At each position from the lower end ■ to the tip ■ of the nozzle 13, the area of the fuel passage formed by the swirl bar 12, the outer peripheral surface, and the inner wall surface of the nozzle 13 is compared with that of the conventional configuration (solid line in the figure) and the present configuration. A comparison is shown with the case of the example configuration (broken line in the figure). In the case of the conventional configuration, as shown by the solid curve,
The passage area changed significantly at the 0 position at the lower end of the swirl bar 12. As mentioned above, this is a factor that causes a sudden change in the fuel flow rate, and is a cause of the occurrence of thinning. On the other hand, in the case of the configuration of this embodiment, as shown by the broken line curve, the passage area changes uniformly, which makes it possible to suppress the occurrence of thinning. Therefore, even if the fuel adheres, it can be dropped before it grows large, and a good spray can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, by simply changing the shape of the lower end of the swale bar, it is possible to prevent the dripping of fuel, which was a problem with the conventional configuration, and to achieve good fuel spray. can.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional electromagnetic fuel injection valve, Fig. 2 is a sectional view showing fuel spray and conditions in the conventional configuration, Fig. 3 is a sectional view for detailed explanation of the present invention, and Fig. 4. is a diagram comparing fuel passage areas. DESCRIPTION OF SYMBOLS 1... Fuel injection valve, 2... Fixed iron core, 3... Yoke, 4... Excitation coil, 5... Plunger, 6...
・Ball valve, 7... Stopper, 8... Return spring, 9... Filter, 10... Fuel inlet, 11...
Swirl orifice, 12... Swirl bar, 13.
... Nozzle, 14... Plunger rod, 15...
valve seat. Agent Patent Attorney Akio Takahashi 11 Figure/J/2 T2 Figure'i4 Nagi■ ■ ■■ ■Kara/D Tosho

Claims (1)

[Claims] 1. A movable valve, in which a movable core and a valve are integrally connected, is placed on the inner diameter of a fixed core that is magnetized by energizing an excitation coil, and is slidable in the vertical direction, and between this movable valve and the fixed core. The movable valve gauge is moved up and down by the spring force of the provided return spring and the suction force of the fixed iron core to open and close the valve seat provided at the opening of the fuel injection passage. In the electromagnetic fuel injection valve, the electromagnetic fuel injection valve is provided with a school orifice having a diagonal passage, a swirl bar integrated therewith, and a nozzle having a cylindrical inner surface on the swirl orifice side and a truncated cone shape on the fuel outlet side. An electromagnetic fuel injection valve characterized in that the lower end of the swirl bar is formed into a conical shape with a downward vertex.