JPS5859365A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To reduce the vibrations and noises of an engine by a method wherein a passage for relieving a small quantity of fuel at the time of lifting a needle valve to open in a low speed rotation and low load operation zone of the engine including idling is provided through the needle valve and a nozzle head and the injection of fuel during the period in which the ignition of fuel is delayed is controlled. CONSTITUTION:When the engine is operated in a low speed rotation and low load condition including idling, the needle valve 1 is lifted by a predetermined amount due to the pressure of the fuel introduced into a fuel sump 10 and a very small quantity of fuel leakes into a relief port 13 through the fuel relieving passage formed of a passage 24, a vertical groove 21, an annular groove 23 and a passage 25 so that the pressure of the fuel injected from an injection port 16 is lowered and the rate of fuel injection decreases. Consequently, the rotation speed of the engine drops for a moment but a governer senses it and operates to keep the idling or the low speed rotation and low load condition of the engine in such a manner that the period of fuel injection is extended while a small quantity of fuel is kept injected, to thereby prevent the reduction of the quantity of fuel injection.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection valve that includes an idler link and is intended to improve fuel supply in the low-interruption, low-load region of the engine.

In the case of a diesel injector, there is a time delay between when the injector vaporizes and ignites, that is, there is an ignition delay S@. This is long in the low engine rotation low load region including the 4$4/c idle link. Therefore, in the far horizontal region of the Todoroki scissors, most of the fuel is injected during the ignition delay period, and by the time of ignition, the fuel has accumulated and is combusted, resulting in a rapid increase in the rate of pressure rise in the cylinder. There is a risk that so-called diesel knock will occur, and the noise level will increase along with severe engine vibration.

The present invention aims to eliminate the above-mentioned disadvantages of the conventional technology, and is configured to release a portion of the high-pressure fuel in the fuel supply passage in the low-speed rotation and low-load region including the idle link, thereby keeping the fuel injection rate low. The present invention provides a fuel injection valve that lengthens the fuel injection period and reduces the amount of fuel injected during the ignition delay period.

Although it is possible to adopt such a mechanism in a fuel injection pump, in view of the fact that it is difficult to change the design of a fuel injection pump, the present invention aims to easily improve the fuel injection valve. .

The following is a comparison of the injection valves of embodiments of the present invention. , 1 ゛The iris 1 diagram indicates the conventional fuel*fuel consumption.Therefore, there is a
P, 103. ) In the figure, the nozzle head 2 on which the needle valve 1 is slidably disposed, the distance piece 3, and the nozzle body 4 are integrated by a nozzle nut S. The elastic force of a coil spring 60 stored in the spring chamber a of No. 4 is biased in the valve closing direction via the bushing rod T. A cap 12 for the nozzle main body 4Ka fuel supply boat 11 and a cap 14 for the fuel relief port 13 are respectively hinged, and the fuel supply port 11 is formed in the nozzle main body 4, the distance piece 3, and the nozzle head 2. It is connected to a fuel reservoir 10 in the nozzle head 2 via a nine fuel supply passage 15. The pressure receiving surface of the 10Ka needle valve 1 faces the fuel reservoir. Therefore, when fuel pumped from a fuel injection pump (not shown) is introduced into the first batch 10 through the fuel supply port 11 and the fuel supply passage 15, and the pressure of this fuel is increased to a predetermined valve opening pressure or higher, The needle valve 1 receives this on its pressure receiving surface and is lifted against the elastic force of the coil spring 60, and fuel is injected from the injection port 16 connected to the fuel reservoir 10.

Excess solvent in the fuel reservoir 10 that has not been used for injection is stored in the gap between the nozzle head 2 and the needle valve 1, and in the spring chamber 4.
a and the nozzle body 4, and returns from the boat 13 to a fuel tank (not shown) via a fuel relief passage 8.

However, the injection rate (fuel injection amount per unit time) characteristic B of such a conventional fuel injector has a steep rise in the fuel injection rate as shown in Fig. ), most of the fuel is injected and supplied within the ignition delay period, and as mentioned above, diesel knock is likely to occur particularly in the low engine speed and low load region.

Therefore, as an embodiment of the present invention, as shown in FIGS.
A vertical groove 21 having a predetermined length in the axial direction is carved in the inner circumferential wall of the groove 2.
The needle valve 1 is provided with an annular #122.23 at both ends of the needle valve 1, and the needle valve 1 is provided with an annular ring #122.23 at a predetermined 7 points of the needle valve 1; A longitudinal passage 24, 25 is provided with an opening (see FIG. 5) communicating with the annular grooves 22, 23, respectively. Then, one passage 24 is connected to the fuel reservoir IOf'iK, and the other passage 25 is connected to the spring chamber 4.
It is always in communication with the fuel relief boat 13 via a, thereby forming a passage for fuel relief.

FIG. 3 shows the closed state of the needle valve 1.
Since the lift is zero, the communication between the vertical #1I21 and the passage 24 is cut off. Moreover, FIG. 4 shows the A-A cross section of Figure 3.

In the above configuration, when the engine is operated at low speed rotation and low load including idling, the needle valve 1 is moved to the fuel reservoir 1.
5th due to 9 fuel pressure which is led to 0! As shown in @l, the passage 24, the annular groove 22, and the vertical groove 21 are lifted by a predetermined violet.
, annular #I2S, and the passages 25 are connected in series, so that a small amount of fuel in the fuel reservoir 10 passes through each of these passages and leaks to the fuel relief board 13 via the fuel relief passages. be done.

As a result of 7, the injection pressure of the fuel injected and supplied from the injection port 16 decreases, and therefore the injection rate decreases. As a result, the amount of fuel injected into the cylinders of the engine decreases instantaneously and the engine rotational speed decreases, but this is sensed and a governor (not shown) acts to act on the fuel injection amount control member of the fuel injection pump ( For example, in the case of a distribution fuel injection pump, the control sleeve (control sleeve) is moved in the direction of fuel increase to maintain idle link or low rotational speed and low load operation state, as shown in FIG. Extend the injection period to 0 to prevent the fuel injection amount from decreasing. As a result, fuel is supplied to the cylinder by injection even after the ignition delay period has elapsed, and explosive combustion takes longer than before, reducing idle knock in the relevant operating region. It is possible to reduce engine vibration and noise.

Note that the base of the fuel leak is the fuel relief passage 211-2.
- By appropriately setting the fifth passage cross-sectional area, the injection rate and injection period characteristics for a predetermined period can be obtained.

Next, in the operating range other than the idle link 7 (including low speed rotation and low load), the oil pressure sent to the fuel injection pump increases, and this is guided to the fuel reservoir 10, increasing the pressure of the needle valve 1. In the low lift region at the initial stage of opening of the valve 1, as mentioned above, each of the fuel relief valves 21-L2s is connected once, and a small amount of fuel flows from the fuel 1@.
In addition, the amount of 7 points increases, so as shown in FIG.
communication with is severed. As a result, normal injection rate and injection period characteristics can be obtained, and a decrease in output can be prevented.

In addition, the initial IC of the needle valve opening! The instantaneous drop in the injection rate results in a small amount of preliminary injection being performed prior to the subsequent large main injection, which shortens the ignition delay period and slows down the combustion of the main injection fuel. It also provides the advantage of making it easier to use.

FIG. 7 Iri concentrated @22.23 is provided on the outer peripheral surface of the needle valve 1, and its operation is the same as in the previous embodiment.

Further, as shown in FIG. 8, a communication passage 2 @ communicating with the fuel supply passage 1° 5 communicating with the fuel reservoir 10 is provided, and this communication passage 28 is connected to the fuel supply passage 2 through the annular # 26 and the vertical groove 21. Even if the communication passage 2 is controlled to open and close by communicating with the relief port 13 and moving up and down as the needle valve 1 opens and closes, it will not work.

In the embodiment shown in FIG. 9, instead of forming an annular groove on the outer periphery of the needle valve 1, the rotation of the needle valve 10 is prevented.
This is prevented by the key 29 attached to the bush rod T.
The rotation of itself is formed on the bush rod 1 and the nine-piece part 30
This is prevented by the medium-#$31 formed on the distance piece 3.

It should be noted that the passage for releasing a small amount of fuel from the fuel reservoir when the valve is opened during low-speed rotation and low-load operation, including idling of the engine, is not limited to the above-mentioned embodiment, and may include various modifications. Not even □.

For example, in FIG. 3, the annular groove 23 and the fuel reservoir 1° are communicated through a passage provided in the nozzle head 2. In this way, communication between the passage 25 and the annular groove 23 is required when the needle valve is shut off and during high speed/lift, and communication is required in the valve opening range during low speed rotation and low load, including idling, to allow fuel to escape. I can do it.

As described above, according to the present invention, the fuel injection valve is configured to release a small amount of supplied fuel when the valve is opened in the low-speed rotation and low-load operating region of the aircraft, including the idle link. It is possible to lengthen the tIlA injection period in the transition region, and most of the fuel is no longer injected during the ignition delay period, thus preventing the conventional disadvantages of explosive IIC combustion. The engine vibration and noise level caused by diesel knock can be reduced. In addition, the fuel can be released by simply modifying the needle valve and nozzle head of the conventional injection valve, and there is no need to separately change the design of the injection valve.

[Brief explanation of drawings]

Fig. 1 is a graph of a conventional fuel injector, Fig. 2 is a graph comparing and contrasting the injection rate characteristics of the present invention and the conventional fuel injector, and Figs. 3 to 6 are an example of the present invention. shows,
Fig. 3 is a vertical cross-sectional view when the valve is closed, Fig. 4 is a cross-sectional view taken along the line A-A of the same as above, and Fig. 5 is a vertical cross-sectional view of the valve when the valve is closed. FIG. 6 is a vertical cross-sectional view of an engine operating area other than the above when the valve opening height is 7, and FIG. 7 is a vertical cross-sectional view of another embodiment of the present invention when the valve is closed. FIG. 8 is a longitudinal cross-sectional view of another embodiment of the present invention, and FIG. 9 is a longitudinal cross-sectional view of another embodiment of the present invention. 1... Knee)" valve 2... Nozzle head 4a.
・・Spring chamber ・・Fuel relief passage 10・・
・Fuel reservoir 15...Fuel supply passage 21...
Vertical groove 22.23...Annular #I 24.25...
Passage patent Applicant Nissan Motor Co., Ltd. Patent attorney Fujio Sasashima tb 2rA 311 6 4al1 25' 5 j15Figure 6 116Figure Ji7jill Figure 8

Claims (1)

[Claims] In the fuel injection valve KThh, the lift amount of the needle valve changes according to the fuel pressure according to the operating condition.The needle valve and the valve slide through the fuel relief passage that connects the fuel reservoir and the fuel relief passage. The fuel relief passage is provided in the nozzle head to communicate with the valve by moving the needle valve in the valve opening region when the engine is running at low engine speed (including idling). Characteristic fuel injection valve.