JPS61123755A - Electromagnetic fuel injection valve - Google Patents

Abstract

PURPOSE:To improve the linearity and reproducability of fuel injection by providing a fuel path communicating from the valve body to the fixed core in a movable core while providing a circulation path communicating from said path to the outside of fuel injection valve. CONSTITUTION:Fuel will flow through fuel inlet port 8 of valve guide 10 then swirled through a swirl orifice 9 upon opening of ball valve 7 and injected through a nozzle 11. Here, a portion of fuel fed through said port 8 will flow out through an annular gap formed by a valve guide 10 and a plunger rod 6 in the direction of plunger 5 then through the fuel flow paths 14, 14' of bobbin 17 to the outside of fuel injection valve 1. Then said fuel is flowed to a pressure regulator without storing at the outercircumference of yoke 3 thus to cool the yoke 3 continuously. Since damping function of fuel can be reduced, the linearity and the reproductionability of fuel injection can be improved.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to electromagnetic fuel injection valves, and particularly relates to a structure suitable for improving linearity, repeatability, and temperature characteristics of fuel injection amount. Concerning what you have.

[Background of the invention]

A conventional example is shown in FIG. In the fuel injection valve IVc, a ball valve 7, a plunger rod, and a plunger 5, which is a movable iron core, are integrated to form a movable foot valve. In this movable valve, a magnetic circuit is formed in the plunger 5, core 2, and yoke 3 by applying a current to the coil 12, and the plunger 5 is attracted toward the core 2. When the current is turned off, the attractive force disappears, and the movable valve returns to its original state by the force of the spring 13. The fuel is measured by repeating this suction-return operation. When this movable valve is attached to an engine and operated, the frequency range is from 20Hz to 300Hz.
Since it is necessary to drive over a wide range of frequencies up to Hz, it is necessary to improve response (1) to improve repeatability (2) to stabilize the injection amount custom-made. Regarding 1, it is possible to deal with it by designing an optimal magnetic circuit and selecting the magnetic material, but regarding 2, it is necessary to minimize the mechanical loss of the sliding part and the damping effect of the fuel to make the operation uniform. In this conventional example, there is no fuel flow passage in the joint between the granger 5 and the plunger rod 6, so when the movable valve operates, the fuel accumulated in the fuel reservoir 16 expands and compresses within a minute. As a result, the valve opening and closing operations are inconsistent due to the damping effect of the fuel, which worsens repeatability.

Incidentally, examples related to this type of electromagnetic injection valve include, for example, Japanese Patent Application No. 58-143814.

Another conventional example has a structure in which two or more openings are formed in the front and rear parts of the injector, as described in Japanese Utility Model Application Publication No. 57-136864, so that fuel circulates within the injector. The purpose of this is to prevent heat generation in the coil during injector operation, but in this conventional example, only cooling from the inside of the bobbin can be expected, and although the worst situations such as burnout of the coil and melting of the bobbin can be prevented, the fuel temperature Because the coils were not sufficiently cooled during ascent, the amount of fuel injected changed significantly, causing a deterioration in the accuracy of air-fuel ratio control.

[Purpose of the invention]

An object of the present invention is to provide an electromagnetic fuel injection valve that overcomes the drawbacks of the prior art described above, improves the linearity and repeatability of the fuel injection amount, and has excellent temperature characteristics. be.

[Summary of the invention]

The present invention focuses on the fact that the fuel reservoir 16 at the lower end of the plunger 5 causes a fuel dumping effect, and
In order to constantly circulate the fuel in the fuel reservoir 16, a fuel passage leading from the stopper 4 side to the core 2 side is formed at the joint between the plunger 5 and the plunger rod 6 and at the receptacle of the spring 13 of the plunger. A flow path is provided that communicates between the passage and the outside of the fuel injection valve 1, and a fuel circulation path is also formed outside the yoke 3 to promote cooling of the coil 12.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. In the present invention, a part of the plunger rod 6 is formed with a flat surface at the joining part with the plunger 5 so that a fuel flow path is formed even after joining, and the spring 13 receiver of the plunger 5 is provided with a hole. The fuel flow path was formed. Fuel flows in from the fuel inlet hole 8 of the pulp guide 10, and when the ball valve 7 opens, it is swirled by the swirl orifice 9 and is injected from the nozzle 11 with a uniform spread and angle.

A portion of the fuel from the fuel inlet hole 8 flows out toward the plunger 5 through the annular gap formed by the pulp guide 10 and the plunger rod 6, and flows through the fuel passages 14' and 14 provided in the bobbin 17. It flows out of the injection valve 1.

The fuel flowing out of the fuel injection valve l does not reach the outer periphery of the yoke 3 and flows to the pressure regulator that controls the fuel pressure, so the yoke 3 is constantly cooled, and the yoke 3 is cooled by cooling the yoke outer periphery. Since the cooling effect is greater than that of the conventional technology (Utility Model Application Publication No. 57-136864) RC, the following effects can be obtained.

FIG. 3 shows the fuel injection amount characteristics (dotted line) of the fuel injection valve 1 of the present invention with the horizontal axis: pulse width and the vertical axis: fuel injection amount. By forming a fuel flow path in the plunger 5 part, damping effect can be prevented, so the lower limit of the linear fuel injection amount can be achieved compared to the conventional technology (solid line) by improving the opening and closing operations of the movable valve. The value was improved from q to q, and the repeatability was also reduced by half compared to the conventional technology.

Furthermore, the formation of this fuel flow path is also effective in reducing changes in fuel injection amount due to changes in fuel temperature.

In other words, when the fuel temperature rises, it is thought that the viscosity coefficient of the fuel will decrease and that bubbles will be generated inside the fuel injection valve 1. However, with this configuration, as shown in Fig. 4, compared to the conventional technology (solid line), We were able to keep the amount of fuel change to about 173. (
(The horizontal axis in Figure 4 shows the fuel temperature, and the vertical axis shows the rate of change in injection amount.)
[Effects of the Invention] According to the present invention, since the damping effect of the fuel can be reduced, the linearity and repeatability of the fuel injection amount can be improved, and it is also effective in terms of temperature characteristics caused by the fuel temperature.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional fuel injection valve, FIG. 2 is a longitudinal sectional view of a fuel injection valve of the present invention, and FIG.
The 1% characteristic diagram and FIG. 4 show the fuel injection amount change rate with respect to fuel temperature change. 1... Fuel injection valve, 2... Core, 3... Yoke,
4... Stopper, 5... Plunger, 6... Plunger rod, 7... Ball valve, 8... Fuel inlet hole, 9... Swirl orifice, 10... Pulp guide, 11... ...Nozzle, 12...Coil, 13.
... Sprinkle, 14. 14'... Fuel flow path, 15.
・Spring adjuster, No. 16, No. 3 in Fig.

Claims (2)

[Claims] 1. A coil assembly including an electromagnetic coil and a fixed iron core is fixed inside the injection valve body, a valve seat is provided at the opening of the fuel injection passage, and a movable valve in which a valve body for opening and closing the valve seat and a movable iron core are combined is provided. In an electromagnetic fuel injection valve that is caused to reciprocate by the attractive force of a fixed core excited by an electromagnetic coil and a return spring interposed between the movable valve and the fixed core, the fixed core is moved inside the movable core from the valve body. An electromagnetic fuel injection valve having a passage A leading to the fuel injection valve, and a circulation passage leading from the passage A to the outside of the fuel injection valve. 2. In claim 1, the circulation passageway comprises:
An electromagnetic fuel injection valve characterized by being provided above a gap formed by a movable iron core and a fixed iron core.