JPS59162359A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To provide for well-controlled injection condition and improve combustion performance of a fuel injection valve of an Internal combustion engine by providing both a lift regulating member which is reciprocatively fitted inside the valve body and an opening/closing valve which opens/closes an injection nozzle. CONSTITUTION:The fuel injection valve has a lift regulating member 13 which is slidably fitted inside the body 10 thereof, an opening/closing valve 15 which is slidably fitted inside a nozzle 11, and nozzle holes 16 and 17. At the low load running time of an engine, pressure oil is fed from a working oil inlet hole 24 into a working oil chamber 23 to push down the member 13. Under such state, fuel is sent via fuel inlet passages 20 and 21 to push up an opening and closing valve 15. Consequently, a valve 18 is lifted by a clearance (b) to open the lower nozzle hole 17 only. Fuel is then injected under the well controlled condition across the overall running range of a low load, thereby improving combustion performance.

Description

[Detailed description of the invention] The present invention relates to a fuel injection valve for an internal combustion engine.

FIG. 1 shows an example of a conventional fuel injection valve for an easel engine, in which l is the valve body, 2 is the nozzle, 8 is the needle valve, 4 is the injection hole, and 5 is the needle valve spring.

6 is a fuel inlet passage.

In such a conventional fuel injection valve, the passage area of the nozzle injection hole 4 must be the same from the high load range to the low load range, so the low load range ft! ,.

In this case, the boiler injection amount decreases and the fuel injection pressure also decreases. For this reason, there is a problem in that the spray condition of the fuel injected from the nozzle hole 4 of the nozzle 2 deteriorates, causing poor combustion.

The present invention has been made in view of the point -F, and an object of the present invention is to provide a fuel injection valve that can improve the spray condition and improve the combustion performance over the entire operating range from the high load range to the low load range.

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 2. 10 is a valve body, 11 is a nozzle, and 1B is a main body 1.
1.4 is a connector fixed to the main body IO and the nozzle 11; 15 is an on-off valve slidably fitted in the nozzle 11; 16.
17 is a nozzle hole, 18 is a valve spring, and 19 is a lift adjustment member 1.
20.21 is a fuel inlet passage, 22 is a fuel reservoir, 28 is a hydraulic oil chamber formed so that the top surface of the rifling/adjusting member 18 faces inside the main body [0], 24 is a return spring B; This is the introduction hole for hydraulic oil.

The foot adjustment part 13 indicated by -F is formed so that when pressure oil is introduced into the hydraulic oil chamber 23, a gap a exists between its -E surface 18i and the lower surface 10a of the main body IO.

Further, the on-off valve 15 is pushed against the nozzle 11 by the elasticity of the valve spring 18, and the lift adjustment member 18
is pressed against the −F end face of the connector 14, and the above-mentioned gap a
is formed so that a gap exists between the upper surface 15a and the lower surface 18b of the adjustment member 18.

Furthermore, the above-mentioned nozzle hole 16. +7 is drilled at a position that satisfies the following conditions (1) to (2).

(2) When the on-off valve 15 is pressed against the shoulder surface 11a of the nozzle 11, both nozzle holes 16 and 17 are closed by the valve 15.

■ When the upper surface 18g of the lift adjusting member 18 and the lower surface 10a of the main body 10 are in contact with each other (with a gap a='0), and the upper surface 15a of the on-off valve 15 is in contact with the lower surface 18b of the adjusting member 18 (with a gap of 20). ), both nozzle holes 16 . '17 is drilled. (The lower end edge 15b is located at FIG.
When a and the lower surface iab of the adjustment member 18 come into contact (gap b=0), only the lower nozzle hole 17 is opened. (The lower end edge +5b of the valve is located in FIG. 2A.) In an internal combustion engine equipped with the above fuel injection valve.

During low load operation of an engine with a small amount of fuel injection.

Pressure oil is introduced into the hydraulic oil chamber 28 from the hydraulic oil introduction hole 24. This pressure oil acts on the upper surface of the lift adjustment member 18 and pushes it down against the elasticity of the return spring 19 as shown in FIG.

In this state, when fuel is introduced through the fuel inlet passage 20.21, this fuel acts on the lower end surface 15b of the on-off valve 15 and pushes it up against the elasticity of the valve spring 18. As a result, the valve 18 is lifted by the amount of the gap (the lower end surface 15b of the valve 15 is at the position A in FIG. 2), and only the lower nozzle hole 17 is opened. In this case, the amount of fuel injected is small depending on the load, but since the nozzle hole 16 is closed, the nozzle hole area becomes small, and therefore a high injection pressure can be maintained.

During high-load operation of two engines with a large amount of fuel injection, when the pressure oil in the two hydraulic oil chambers 2B is released, the lift adjustment member 18
is returned in the -F direction by the elasticity of the return spring 19, and the gap a =
It becomes 0.

When fuel is introduced in this state, the fuel acts on the lower surface of the on-off valve 15 and pushes it down. As a result, valve 18
is lifted by the amount of gap a+b]
5b is in position B in FIG. 2) All of the upper and lower nozzle holes 16 and 17 are opened, and a large amount of fuel corresponding to the load is injected into the sill. In this case, the area of the injection hole has increased to about twice that of the low load, so there is no abnormal increase in the injection pressure.

Note that compressed air may be introduced into the hydraulic oil chamber 28.

In addition, the nozzle holes 16 and 17 are provided in two stages, but there are eight stages.
It may also be F.

The present invention is constructed as described above, and according to the present invention, it is possible to prevent a decrease in fuel injection pressure in a low load range, and a higher fuel injection pressure can be obtained than in the conventional system.

Therefore, the particle size of the spray can be reduced, and the reach of the spray can be extended, resulting in good combustion.
Fuel consumption rate can be reduced.

In addition, when operating one engine for a long time at low load, conventionally it was necessary to replace the nozzle with one designed for low load operation, but with the present invention, one type of nozzle can be used to meet all operating conditions. Therefore, such replacement work is not required.

Therefore, the ease of handling of the engine is also improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one example of a conventional fuel injection valve, and FIG. 2 is a view corresponding to FIG. 1 showing one embodiment of the present invention. 10...Body, 11...Nosle, 18...Lift adjustment part month. 15...Opening/closing valve, 16.17...Nozzle hole, 23...
Hydraulic oil chamber 363-

Claims (1)

[Claims] A plurality of nozzle holes are formed at the tip of the nozzle along the axial direction thereof, a lift adjustment member is reciprocatably fitted into the valve body, and the adjustment member is formed on the upper part of the lift adjustment member. a working fluid chamber in which working fluid acting on the upper surface of the chamber is supplied and discharged;
- It is provided so as to be movable relative to the foot adjustment member described in h in the axial direction of the nozzle, and the movement of more than a certain amount is regulated by the adjustment member, and in cooperation with the adjustment member, all or one of the nozzle holes is A fuel injection valve characterized by comprising an on-off valve that opens and closes a portion of the fuel injection valve.