JPH10176630A - Fuel injection nozzle for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the atomization of fuel and the dispersion thereof over a wide range by a fuel injection nozzle comprising a needle valve element which is held inside a nozzle body and is integrally formed with a pin part inserted through a nozzle hole formed through the head face of the nozzle body. SOLUTION: A nozzle body 1 is perforated with a plurality of subsidiary nozzle holes 11 such that their one ends are situated between a valve part 5 of a needle valve element 4 adapted to contact with a valve seat face 6 of the nozzle body 1 and a pin part 10 thereof and the other ends are situated on a head face 2 of the nozzle body 1. The needle valve element 4 is formed with spiral grooves 13 at the outer periphery of its part 12 exposed to a fuel sump 9 defined inside the nozzle body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pintle or throttle type fuel injection nozzle for supplying fuel to a combustion chamber of a diesel engine.

[0002]

2. Description of the Related Art In general,
Pintle or throttle type fuel injection nozzles are well known in the art, and as described in, for example, Japanese Utility Model Publication No. 61-8223, a pin portion is integrated with a needle valve body housed in a nozzle body. The pin portion is inserted into the ejection hole of the nozzle body so that the fuel is ejected from the ejection hole in a hollow conical shape.

However, simply ejecting the fuel in the shape of a hollow cone as described above has a limit in miniaturization of the fuel, so that unburned components such as HC are increased in the exhaust gas. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pintle or throttle type fuel injection nozzle in which the injected fuel is made finer to reduce unburned components.

[0004]

In order to achieve this technical object, a first aspect of the present invention is to provide a structure in which a pin portion is integrally provided on a needle valve body housed in a nozzle body.
In a fuel injection nozzle which is inserted into an injection hole formed in the nozzle body so as to open at a tip end surface thereof, a plurality of auxiliary injection holes are provided in the nozzle body, and one end of the auxiliary injection hole is provided with the needle. The other end of the valve is bored in a portion between the valve portion and the pin portion that contacts the valve seat surface on the nozzle body side so that the other end opens to the tip end surface. A helical groove is provided on an outer peripheral surface of a portion of the nozzle main body that is viewed in the fuel reservoir. ".

According to a second aspect of the present invention, a pin portion is provided integrally with a needle valve body housed in a nozzle body, and the pin portion is bored in the nozzle body so as to open at a tip end surface thereof. A plurality of sub-injection holes, one end of which is in contact with the valve seat surface of the needle valve body on the nozzle body side in the nozzle body. The other end is bored in the portion between the valve portion and the pin portion so that the other end is opened at the tip end surface, while the fuel from each of the sub-ejection holes is axially When viewed from above, the nozzle is configured to be ejected tangentially to the ejection hole. "

[0006]

According to the first aspect of the present invention, the fuel supplied into the fuel reservoir in the nozzle body is ejected from the ejection hole into a hollow conical shape while pushing up the needle valve body under the pressure. Therefore, the fuel is also ejected from each sub-ejection hole. At this time, the fuel flowing from the fuel reservoir toward the ejection hole and each of the sub-ejection holes is provided with a swirling flow by a spiral groove provided in a portion of the needle valve body in the fuel reservoir, By this swirling flow, the cone angle when fuel is ejected from the ejection hole can be widened, and a swirling motion can be imparted to the hollow cone, so that the fuel can be miniaturized and a wide area can be applied. On the other hand, since the influence of the swirl flow still remains on the fuel ejected from each of the sub-ejection holes, the fuel ejected from each of the sub-ejection holes can be miniaturized. It can be distributed over a wide area.

[0007] As a result, the fineness of the fuel injected from the fuel injection nozzle and the dispersion over a wide area can be greatly improved, so that unburned components such as HC in the exhaust gas can be surely reduced. Have. Further, by configuring as in the above “Claim 2”, the fuel from each sub-injection hole is ejected in a direction tangential to the ejection hole, in other words, the fuel ejected from each of the sub-injection holes. Since a spiral or spiral motion can be imparted, and the fuel jetted from each sub jet hole can be further miniaturized and dispersed over a wide area, the same effects as described above can be obtained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment, in which reference numeral 1 denotes a nozzle main body, and an ejection hole 3 formed in the nozzle main body 1 so as to open to a front end surface 2 thereof. A valve spring 4 for urging the needle valve 4 so that the valve portion 5 at the lower end thereof always contacts the valve seat surface 6 on the nozzle body 1 side;
A fuel reservoir 9 into which pressure fuel from a fuel injection pump (not shown) is introduced through a passage 8 is provided at the valve seat surface 6.

Further, the needle valve element 4 is integrally provided with a pin portion 10 inserted into the ejection hole 3, and the fuel supplied into the fuel storage chamber 9 is supplied to the needle valve element 4 by the pressure. Is pressed out against the spring 7 and is ejected from the ejection hole 3 in a hollow conical shape. The nozzle body 1 is provided with a plurality of sub-injection holes 11, the valve portion 5 having one end of the sub-injection hole 11 abutting on the valve seat surface 6 of the needle valve body 4 on the nozzle body side, and the pin. Part 10
And the other end is opened in the front end face 2 so as to open each.

Further, a portion 12 of the needle valve 4 which is viewed in a fuel reservoir 9 provided in the nozzle body 1
Is provided with a spiral groove 13 on the outer peripheral surface. In this configuration, the fuel supplied into the fuel reservoir 9 in the nozzle body 1 is ejected in a hollow conical shape from the ejection hole 3 while pushing up the needle valve body 4 with the pressure, and at the same time, the fuel is supplied to each of the sub-ejection holes 11. Will also erupt.

At this time, the fuel flowing from the inside of the fuel reservoir 9 toward the ejection hole 3 and each of the sub-ejection holes 11 is provided with a spiral groove provided in a portion 12 of the needle valve body 4 in the fuel reservoir 9. A swirl flow is given by the fuel flow 13, and by this swirl flow, the cone angle when fuel is ejected from the ejection hole 3 can be widened, and a swirling motion is performed on the hollow conical fuel. Since it is possible to provide the fuel, it is possible to reduce the size of the fuel and to disperse the fuel in a wide area.
Since the influence of the swirling flow remains, each sub-jet hole 11
The fuel ejected from the fuel can be miniaturized and dispersed over a wide area.

In this case, as shown in the drawing, the inner peripheral surface of the fuel storage chamber 9 is configured to be close to the outer peripheral surface of the portion 12 of the nozzle body 4 where the spiral groove 13 is provided, so that the swirling flow is achieved. Can be further strengthened, and the length L of each sub-ejection hole 11 is set to be 5 times or less the inner diameter D of the sub-ejection hole 11, so that the jetting from each sub-ejection hole 11 is performed. Since the influence of the swirling flow remains more strongly on the fuel that flows, the spiral or spiral motion can be imparted to the fuel ejected from each sub-ejection hole 11 as shown by the arrow A in FIG. In addition, it is possible to further improve the miniaturization and dispersion of the fuel over a wide area.

Next, FIGS. 4 and 5 show a second embodiment. In the second embodiment, the fuel from each of the sub-ejection holes 11 is ejected in a tangential direction to the orifice 3 as shown by an arrow B when viewed from the axial direction. Except for the configuration, the other configuration is the same as that of the first embodiment. As described above, each sub-injection hole 11 is configured so that fuel from each sub-injection hole 11 is ejected in a tangential direction to the above-described injection hole 3 as shown by an arrow B when viewed from the axial direction. The fuel from each sub-injection hole 11 is ejected in a direction tangential to the ejection hole 3, in other words, the fuel ejected from each of the sub-injection holes 11 can be imparted with a spiral or spiral motion. Therefore, it is possible to further improve the miniaturization and dispersion of the fuel over a wide area.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a bottom view of FIG. 2;

FIG. 4 is an enlarged sectional view of a main part showing a second embodiment of the present invention.

FIG. 5 is a bottom view of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle main body 2 Tip surface 3 Injection hole 4 Needle valve element 5 Valve portion 6 Valve seat surface 9 Fuel reservoir 10 Pin portion 11 Sub-injection hole 12 Part to be viewed in fuel reservoir 13 Spiral groove

Claims (2)

[Claims] 1. A pin portion is integrally provided on a needle valve body housed in a nozzle body, and the pin portion is inserted into an ejection hole formed in the nozzle body so as to open at a tip end surface thereof. In the fuel injection nozzle, a plurality of sub-injection holes are provided in the nozzle body, and one end of the sub-injection hole contacts the valve seat surface of the needle valve body on the nozzle body side and the pin portion. A spiral groove is formed on the outer peripheral surface of a portion of the needle valve that is viewed in a fuel reservoir provided in the nozzle body, while the other end is bored in the portion between the two so that the other end opens to the distal end surface. A fuel injection nozzle for a diesel engine, wherein the nozzle is provided. 2. A pin portion is integrally provided on a needle valve body housed in a nozzle main body, and the pin portion is inserted into an ejection hole formed in the nozzle main body so as to open at a tip end surface thereof. In the fuel injection nozzle, a plurality of sub-injection holes are provided in the nozzle body, and one end of the sub-injection hole contacts the valve seat surface of the needle valve body on the nozzle body side and the pin portion. While the other end is drilled in the portion between them so that the other end opens to the front end face, each of the sub-ejection holes is formed such that the fuel from each of the sub-ejection holes is viewed from the axial direction with respect to the above-mentioned emission hole. A fuel injection nozzle for a diesel engine, which is configured to jet in a tangential direction.