JPH02102366A - Fuel injection nozzle of diesel engine - Google Patents

Abstract

PURPOSE:To improve the mixing of the fuel and the air and to promote to make the fuel into minute particles by providing air leading inlets whose one ends are opened to the outside of a nozzle holder and the other ends are opened to the fuel injection ports, at the end of the fuel injection port side of the nozzle holder in which the fuel injection ports are opened at one end. CONSTITUTION:A large diameter of hollow 4 is engraved at the upper part of the nozzle body 3 in a fuel injection nozzle, while a small diameter of hollow 5 linking to the hollow 4 is engraved at the lower part, and a needle valve 6 is inserted to the hollows 4 and 5 movable up and down. At the lower part of the nozzle body 3, is provided a fuel chamber 10 which can link to a fuel passage 7 when the needle valve 6 goes up, and plural fuel injection ports 11 which are formed in a down slope to the outside of the fuel chamber 10 when observed from the side, and in a radial form when observed horizontally, are opened. In this case, plural air leading inlets 22 in the radial form horizontally and crossing to the fuel injection ports 11, whose one ends are opened to the outside of the nozzle body 3 and the other ends are opened to the fuel injection ports 11, are engraved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fuel injection nozzle for a diesel engine that achieves good mixing of fuel and air to atomize the fuel.

[Prior art] An injection nozzle is used to inject high-pressure fuel sent from an injection pump into the combustion chamber of a diesel engine, but it mixes fuel and air well during injection and atomizes the fuel. It is very important to improve the combustion efficiency of diesel engines and reduce exhaust gas.

To explain the conventional fuel injection nozzle of a diesel engine with reference to FIGS. 3 to 5, a nozzle body 3 fixed by a nozzle nut 2 is attached to the lower end of the nozzle holder, and the upper part of the nozzle body 3 is attached to the lower end of the nozzle holder. , a large-diameter hollow part 4 and a small-diameter hollow part 5 communicating with the hollow part 4 are bored in the lower part of the nozzle body 3, and a needle valve 6 is fitted into the hollow part 4.5 so as to be able to rise and fall. has been done. The upper part of the needle valve 6 has a large diameter and can slide against the hollow part 4.
The lower part thereof has a small diameter, and a gap is formed between it and the hollow part 5 to serve as a fuel passage 7. Further, the stepped portion formed by the large diameter portion and the small diameter portion of the needle valve 6 serves as a pressure receiving portion 21 .

A valve seat 8 having an inverted truncated conical shape is formed on the lower end surface of the fuel passage 7, and the lower end tapered portion 9 of the needle valve 6 can be moved into and out of the valve seat 8.

At the bottom of the nozzle body 3, a fuel passage 7 is formed when the needle valve 6 is raised.
A fuel chamber 10 that can communicate with the fuel chamber 10 is provided, and the fuel chamber 10 has a plurality of fuel injection ports 1 that are formed to be inclined downwardly toward the outside of the fuel chamber IO when viewed from the side and are formed radially when viewed from above. ■Or connected.

A fuel chamber 12 having an inner diameter larger than the inner diameter of the fuel passage 7 is formed at one end of the fuel passage 7 in the nozzle body 3, and fuel is supplied to the fuel chamber 12 in the second part of the fuel chamber 12. A fuel passage 13 is bored to extend in the axial direction of the nozzle body.

A bushing rod 1 is provided integrally with the needle valve 6 at the upper end of the needle valve 6.
The bushing rod 14 extends into two parts by passing through the nozzle holder hollow part, and a coil spring 16 is set at the upper end of the bushing rod 14 via a seat 15. The coil spring 1G is connected to an adjusting screw 17 or a shim. The set pressure can be adjusted by changing the thickness.

In the figure, reference numeral 18 indicates the fuel passage 1 bored in the nozzle holder.
A fuel passage communicating with 3 and 20 are fuel sprays.

The fuel forcefully fed from the injection pump through the fuel passages 18, 13 applies an upward force to the pressure receiving portion 21 of the needle valve 6 in the fuel chamber 12, thereby pushing the needle valve 6 downward.

The valve opening pressure is set by a coil spring 16, and when the pressure exceeds the set pressure, the needle valve 6 is pushed upward, and the tapered portion 9 of the needle valve 6 is separated from the valve seat 8. For this reason,
The fuel in the fuel chamber 2 flows from the fuel passage 7 through the lower end of the needle valve 6 through the opening formed between the valve seat 8, passes through the fuel chamber 10, and is sprayed into the combustion chamber of the diesel engine at high speed from the fuel injection port II. It is injected as.

[Problem to be solved by the invention] However, with two fuel injection nozzles, the mixture of the injected fuel and air is not necessarily sufficient, and the atomization of the fuel is insufficient, resulting in poor ignition. There are problems such as a time delay and a prolonged combustion time, resulting in a decrease in combustion efficiency and an increase in exhaust gas and combustion noise.

The present invention has been made in view of the above-mentioned circumstances, with the object of achieving sufficiently good mixing of injected fuel and air and atomizing the fuel.

[Means for Solving the Problems] The present invention includes a needle valve that is movable in the axial direction of the nozzle holder and a pressure receiving part that opens the needle valve when a predetermined fuel pressure is applied to the outer periphery of the intermediate part of the needle valve. In a fuel injection nozzle for a diesel engine, the fuel injection nozzle is provided at an end of the nozzle holder with a fuel injection port that injects the fuel into a diesel engine combustion chamber when the needle valve opens. , an air introduction port is provided with one end opening to the outside of the nozzle holder and the other end opening to the fuel injection port.

[Operation] When a predetermined pressure of fuel is applied to the pressure receiving part of the needle valve and the needle valve opens, fuel is injected into the diesel engine combustion chamber from the fuel injection port at high speed. At this time, due to the ejector effect of the injected fuel, air is introduced from the air introduction port into the fuel injection port, and the fuel and air are injected together from the fuel injection port into the combustion chamber, resulting in good mixing of fuel and air. The fuel is atomized.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show one embodiment of the present invention.

The fuel injection nozzle for the diesel engine of the present invention basically has the same structure as that shown in FIGS. A plurality of air introduction ports 22 whose ends open to the fuel injection ports 11 are bored so that their planar state is radial and intersects the fuel injection ports 11. Components in FIGS. 1 and 2 that are the same as those shown in FIGS. 3 and 4 are given the same reference numerals.

Similar to the fuel injection nozzle shown in FIGS. 3 and 4, an upward force is applied to the pressure receiving part 2I of the needle valve 6 due to the pressure of the fuel.
When the force exceeds the set pressure of the coil spring 16, the needle valve is pushed upward, and the fuel passes through the fuel injection port 11 at high speed and is injected into the combustion chamber of the diesel engine as a fuel spray 20. At this time, due to the ejection effect of the fuel that is injected at a higher speed, the air inlet 22
is introduced into the fuel injection port 11 together with the fuel.
1 and is injected into the combustion chamber of a diesel engine. As a result, the fuel and air are mixed well and the fuel is atomized, reducing ignition delay and combustion time, improving combustion efficiency, reducing exhaust gas, and reducing combustion noise. It is possible to reduce the amount of

In addition, in the embodiment of the present invention, the case where multiple air inlets are provided so as to be radial when viewed from above has been described, but it is also possible to implement the invention with a single air inlet, without departing from the gist of the present invention. Of course, various changes can be made within the scope.

[Effects of the Invention] As explained above, according to the fuel injection nozzle of the diesel engine of the present invention, since the fuel and air are mixed well and the fuel can be atomized, the ignition delay can be reduced.
It is possible to achieve excellent effects such as shortening combustion time, improving combustion efficiency, reducing exhaust gas, and reducing combustion noise.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of one embodiment of the present invention, and FIG.
Figure 3 is an enlarged view of the lower end of the nozzle body in Figure 3, Figure 3 is a longitudinal sectional front view of the conventional example, Figure 4 is an enlarged view of the lower end of the nozzle body in Figure 3,
FIG. 5 is a general explanatory diagram of a fuel injection nozzle for a diesel engine. In the figure, 1 is a nozzle holder, 3 is a nozzle body, 6 is a needle valve,
11 is a fuel injection port, 14 is a bushing rod, 16 is a coil spring, 17 is an adjustment screw, 19 is a fuel, 20 is a fuel spray, 21 is a pressure receiving part, and 22 is an air introduction port.

Claims (1)

[Claims] 1) A needle valve that is movable in the axial direction of the nozzle holder is fitted into the nozzle holder, and a pressure receiving part that opens the needle valve when a predetermined fuel pressure is applied is provided on the outer periphery of the intermediate part of the needle valve, and the above-mentioned In a fuel injection nozzle for a diesel engine equipped with a fuel injection port that injects the fuel into a combustion chamber of a diesel engine when a needle valve opens, one end of the nozzle holder is opened to the outside of the nozzle holder, and one end is opened to the outside of the nozzle holder. A fuel injection nozzle for a diesel engine, comprising an air introduction port whose end opens to the fuel injection port.