JPH0634621Y2 - Engine fuel injector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a fuel for an engine in which air from an assist air passage opened near a nozzle of a fuel injection valve promotes atomization of the fuel. It relates to an injection valve.

(Prior Art) Conventionally, in an engine fuel injection device, in order to promote atomization of fuel, an atmosphere introduction passage (assist air passage) is opened close to an injection port of a fuel injection valve, and an intake air passage downstream of a throttle valve is opened. There is one that allows air (assist air) to flow in by pressure.

Further, as disclosed in, for example, Japanese Patent Application Laid-Open No. 57-108460, a solenoid valve is provided in the assist air passage, and the solenoid valve is opened in synchronization with the fuel injection timing. According to the control using such a solenoid valve, the assist air is intermittently supplied in synchronization with the fuel injection,
Even if the diameter of the assist air passage is set large enough to secure the air amount necessary for atomizing the fuel, the intake air amount will not be too large and the rotation speed will not rise too much when the engine is idle.

However, in such a conventional fuel injection valve, a solenoid valve must be separately provided in the assist air passage, and a control circuit for opening the solenoid valve in synchronization with the fuel injection valve is required. Therefore, there is a problem that the fuel injection device becomes complicated and costly.

Further, as described in the microfilm of Japanese Utility Model Application No. 59-188735 (Japanese Utility Model Application No. 61-103573), a fuel injection valve is provided in an upper body (socket) in which an air introduction passage (assist air passage) is formed. It is also known that the air flow rate passing through the throat of the nozzle provided in the fuel injection direction is controlled according to the operating state,
In this case, the supply of assist air is not synchronized with the fuel injection, and a means for controlling the air passage area by applying a voltage by using a piezo pile and a nozzle tip is required, which is also complicated and costly. Will be the one.

Further, as described in Japanese Patent Laid-Open No. 57-148052, an air supply passage (assist air passage) is opened at the outer periphery of the fuel injection port (fuel injection port), and the air supply passage is provided in the middle of the air supply passage. It is described that the electromagnetic air supply valve is controlled to be opened and closed by a signal associated with a control signal for controlling fuel injection.
After all, it is necessary to incorporate an electromagnetic air supply valve, which inevitably complicates and raises the cost.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems of the prior art. An engine capable of supplying assist air with a simple structure and at a good timing without providing an electrical timing mechanism. It is intended to provide a fuel injection valve.

(Configuration of the Invention) In order to achieve this object, the present invention is configured as follows. That is, in a fuel injection valve for supplying fuel to an engine, which is composed of a socket in which an assist air passage is formed and an injector inserted and fixed in the socket, a plan is provided in front of the fuel injection port in the socket. A jar body is slidably interposed, and the plunger body is urged by a spring in one direction, that is, in a direction toward the injector nozzle hole. A communication passage for guiding the assist air to the fuel injection port side is formed in the plunger body, and the injection pressure acts on the plunger body at the time of fuel injection so that the plunger body moves in the other direction, that is, the fuel injection port side. When it is moved to, the communication passage provided in the plunger body and the assist air passage provided in the socket in which the plunger body is interposed are made to communicate with each other. Further, in this way, the fuel injection pressure is used to actuate the plunger body for supplying the assist air to adjust the supply timing of the assist air. In the fuel injection direction from the injector and the fuel passage of the plunger body, If the fuel injection pressure did not work effectively if the fuel inflow direction to the fuel injection direction was the same and the operation of the plunger body was delayed and assist air could not be supplied in a timely manner. The inlet of the fuel passage formed in the body is offset from the injection hole of the injector.

(Operation) When fuel is injected from the injector, the injection pressure acts on the plunger body, so that the plunger body moves against the spring force and opens the air passage. that time,
Since the inlet of the fuel passage provided in the plunger body is offset with respect to the injection port of the injector, the fuel injection pressure effectively acts on the plunger body, which causes the plunger body to operate responsively and assist air. Is supplied in a timely manner. Then, at the time of fuel injection, air is ejected near the outlet of the fuel, and atomization of the fuel is promoted. Further, when the fuel injection is completed, the plunger body moves in the direction of closing the air passage by the spring. Therefore, air will not be ejected until the next fuel injection.

(Embodiment) FIG. 1 shows an embodiment of the present invention. In this embodiment, the injector 1 is a normal electromagnetic injector that lifts the plunger 3 by energizing the solenoid coil 2 to open the fuel passage, and determines the fuel injection amount by the opening time. The tubular portion of the injector 1 on the injector injection hole 4 side is inserted and fixed in a socket 7 for obtaining assist air. The socket 7 has a fuel injection port 8 at its tip, and a plunger body 5 functioning as an automatic valve is housed between the injector injection hole 4 and the fuel injection port 8. The plunger body 5 is a spring 11
Is urged toward the injector 1 side. The socket 7 is also provided with an assist air passage 6 for guiding the assist air to the fuel injection port 8 side. The plunger body 5 has a fuel passage 9 which penetrates the center portion thereof in a substantially axial direction.
Is provided. The upper portion of the fuel passage 9 is branched into a plurality of oblique holes, so that the upper end opening of the fuel passage 9 does not overlap the injector injection hole 4 when the plunger body 5 is in contact with the lower end of the injector 1. Has become. That is, the inflow port (upper end opening) of the fuel passage 9 is offset with respect to the injector injection hole 4. Further, a groove 12 is provided on the outer peripheral surface of the plunger body 5, and a through hole 10 communicating with the fuel injection port 8 side extends from the groove 12. The groove 12 is provided at a position where the assist air passage 6 is opened when the plunger body 5 moves by receiving the fuel injection pressure. An air communication passage for guiding air to the fuel injection port 8 side is configured. The assist air passage 6 is closed by the side surface of the plunger body 5 when the plunger body 5 is lifted by the action of the spring 11 to a position where it comes into contact with the lower end of the injector 1. It is easy to mount the fuel injection valve configured as described above, for example, in the intake passage downstream of the throttle valve. The assist air is led from, for example, an intake passage upstream of the throttle valve.

When the solenoid 2 is energized and the plunger 3 of the injector 1 moves upward in the figure and fuel is injected from the injector injection hole 4, a fuel pressure acts on the plunger body 5, and the plunger body 5 resists the spring force. Moves downward. The movement of the plunger body 5 causes the assist air passage 6 to groove.
When communicating with 12, the air is sucked from the upstream side of the throttle valve by the negative pressure of the intake air and is ejected near the fuel outlet.
Next, when the energization is cut off and the injection of fuel ends, the plunger body 5 is moved upward by the spring to close the assist air passage 6.

Therefore, according to this embodiment, the injected fuel can be atomized by ejecting air. In addition, in order to secure the amount of air required for atomizing the fuel, the assist air passage 6
Even if the diameter is increased, the assist air passage 6 is closed when the fuel is not being injected, so that the idle rotation speed does not become too high due to excessive air injection. Moreover, since the injector 1 is of a normal type and has a simple structure in which the socket 7 and the plunger body 5 are simply combined, it is extremely advantageous in terms of cost. Further, in particular, since the inlet of the fuel passage 9 provided in the plunger body 5 is offset with respect to the injector injection port 4, the fuel injection pressure effectively acts on the plunger body 5, whereby the plunger body 5 is Responds well,
Assist air is supplied in a timely manner.

It should be noted that in the above embodiment, the description has been made mainly on the premise that the fuel injection valve is provided in the intake passage downstream of the throttle valve. Can also be applied to.
In such a case, the plunger body that functions as an automatic valve will be fully lifted, and not only the air passage but also the fuel passage will be blocked. There is no.

Further, the present invention is not limited to these embodiments and can be implemented in various other modes.

(Effect of the Invention) As described above, since the fuel injection valve of the present invention is configured such that the automatic on-off valve is configured by the plunger body that responds to the injection pressure of the fuel, it has a similar electrical timing mechanism. It is possible to accurately control the ejection of the assist air without using a complicated and expensive device. Further, the injector can be implemented by a simple means by using a normal injector as it is, or by slightly modifying the structure of a socket for normal assist air and incorporating a plunger body in the socket.

Further, in this manner, when the plunger body for supplying assist air is operated by using the fuel injection pressure to adjust the supply timing of assist air, the inlet of the fuel passage formed in the plunger body is By being offset with respect to the injection port, the fuel injection pressure effectively acts on the plunger body, and the plunger body operates with good response, so that it is possible to supply the assist air at a good timing.

[Brief description of drawings]

FIG. 1 is a sectional view of a fuel injection valve according to an embodiment of the present invention. 1: Injector, 2: Solenoid coil, 3: Plunger, 4: Injector nozzle hole, 5: Plunger body, 6: Assist air passage, 7: Socket, 8: Fuel injection port.

Claims (1)

[Scope of utility model registration request] 1. A fuel injection valve for supplying fuel to an engine, wherein a plunger body biased in one direction by a spring is provided in front of a fuel injection port of a socket in which an injector is mounted. The inlet of the fuel passage formed in the above is offset with respect to the injection hole of the injector, and the plunger body is provided with an air communication passage for guiding the assist air to the fuel injection port. The fuel for the engine characterized in that the air communication passage provided in the plunger body and the assist air passage provided in the socket in which the plunger body is interposed are made to communicate by moving by the fuel injection pressure. Injection valve.