JPS60240871A - Fuel jet nozzle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a nozzle for supplying fuel to an internal combustion engine. A nozzle according to the invention has a nozzle body formed with an inner bore and a fuel pressure operated valve member slidable within the bore, the inner bore having an outlet hole extending to the outside of the nozzle body. the valve member includes a cylindrical portion having a valve edge that opens the entrance of the hole to a space receiving high pressure fuel within the nozzle body when the valve member is actuated with pressurized fuel.
a cylindrical valve portion slidable within a portion of the bore defining a cylindrical valve portion;

Prior art and its problems The nozzle described above is of the so-called inwardly or outwardly opening type, and the range of movement of the valve member depends on the fuel pressure, which varies with the engine speed and the rate of fuel supply to the engine.

Since the area of the inner end of the bore depends on the position of the valve member, the nozzle can be automatically adapted to varying engine speeds and fuel supply rates. For example, in order to suitably adapt the fuel injection to the engine speed, a small surface area is required at low speeds and a large surface area is required at high speeds. However, since the cross-sectional area of the hole is constant, the cross-sectional area of the hole must be large enough to provide the necessary fuel injection at high engine speeds and high delivery rates. The inlet area may be reduced by the valve member, but this theoretical advantage would be beneficial if the fuel flow through the hole is such that the pressure energy of the fuel is substantially reduced while the fuel flows through the hole. It won't happen. Loss of energy in the fuel prevents the fuel from atomizing as it exits the hole.

It is an object of the invention to provide a simple and convenient nozzle.

In the nozzle according to the invention, the circumference is formed by the wall of the cylindrical valve part and a surface forming part of the boundary wall of the space, the angle between the surface and the axis of the hole being such that the entrance to the hole is only partially open. In this case, the fuel flowing into the hole is separated from the circumferential edge to form a column of fuel having a free surface inside the hole.

EXAMPLE Hereinafter, an example of a fuel injection nozzle according to the present invention will be described with reference to the drawings.

Referring to FIGS. 1-3, the nozzle includes a body 10 having a bore 11 formed therein. The bore tapers inwardly to form a valve seat 12 and has a cylindrical portion 13 which is preferably properly cylindrical but may be sloped inwardly towards the end of the bore only slightly. Have at the end. A valve member 14 is slidably provided within the inner hole, and the valve member has an enlarged inner hole portion 11Δ in the center and has a reduced diameter at the valve seat portion. The enlarged portion communicates with the outlet of a high-pressure fuel injection pump 9, which is driven synchronously with the attached engine during use.

The valve member is shaped to engage the valve seat 12 and is biased into contact with the valve seat by the coiled compression spring 8.

The gap between the reduced diameter portion of the valve member and the inner hole is indicated by 15,
When the valve member is lifted off the valve seat under the action of pressurized fuel, fuel flows through this gap.

The valve member has at its end opposite the spring a cylindrical valve portion 16 which forms a fuel seal with a portion 13 of the bore, which is preferably properly cylindrical. In this embodiment a pair of exit holes 17 are provided extending from the wall of the cylindrical portion 13 of the bore. These are provided at an angle with respect to the nozzle axis 18, which coincides with the central axis of the valve member and inner bore. As shown in the drawings, the slopes are not the same, but a specific slope is selected depending on the shape of the combustion chamber of the engine to which it is installed. The inner end of the hole is the second
When the valve member is in the closed position as shown in the figure, the valve portion 1 of the valve member
Blocked by 6. A chamber 19 is formed at the end of the inner bore;
This chamber communicates with the inner bore portion downstream of the valve seat through a central hole 20 and a side hole 21.

When pressurized fuel is supplied to the concentric gap 15, the fuel pressure acting on the differential area of the valve member lifts the member away from the valve seat 12 against the action of the spring, and as a result, the fuel flows into the gap. 15
from the holes 21 and 20 into the chamber 19. The valve member must move considerably for the inner end of the hole 17 to open, but once it does, the fuel flows through the hole and is atomized as it exits the hole.

In FIG. 3 the valve member is partially open and the nozzle is referred to as variable area type. The advantage of this is that the effective size of the hole entrance varies with the axial position of the valve member, which can be conveniently varied to match the rotational speed of the engine and the amount of fuel supplied to the engine.

To achieve good atomization of the fuel when the area of the inlet is small, it is necessary to ensure that the velocity of the fuel flowing through the hole is maintained. To achieve this, one edge 22 must have a suitable shape to ensure that the fuel separates from one edge and forms a free surface 23 (FIG. 3) as it flows through the hole 17. is necessary. One edge 22 is connected to the properly cylindrical portion 16 of the valve member and the surface 2 formed at the end of the valve member.
4 and has an angle slightly smaller than the angle made by the hole with respect to the axis 18 of the valve member. Hole 17 in Figure 2
The angle formed by the plane 24 is marked by the letter J, and the angle of the surface 24 is marked by the letter H. It has been found that satisfactory results can be obtained by making angle H smaller than angle J.

Surface 24 can be formed by a simple lathe operation. , 2 or 1
1'''''n1dHt6hf7'u7 (7) Cod 1" Touch 6
d is chosen so that the angle of surface 24 fits into the hole with the smallest angle J.

As mentioned above, this nozzle is a nozzle that opens inward. However, the present invention is also applicable to an outwardly opening nozzle as shown in FIG. It has at its outer end a properly cylindrical valve head 26 which opens at its inner end. The valve head 26 has an edge 29 formed at the intersection of the cylindrical wall of the valve member and the concentric circular surface 30. Angles H and J are also shown in Figure 4, but since this is an outwardly opening nozzle, the angles are shown relative to a plane perpendicular to the axis of the nozzle. The aforementioned space is formed in the reduced diameter portion of the valve head downstream of the valve seat.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the nozzle, FIG. 2 is an enlarged cross-sectional view of the nozzle end with the valve member in the closed position, and FIG. 3 is a cross-sectional view of the nozzle end with the valve member in the partially open position. A sectional view similar to FIG. 2, and FIG. 4 an enlarged sectional view of the outwardly opening nozzle. 8... Spring, 9... Injection pump, 10... Nozzle body, 11... Inner hole, 11A... Inner hole enlarged part, 12
... Valve seat, 13... Cylindrical portion, 14... Valve member, 15... Gap, 16... Cylindrical valve portion, 17...
・Exit hole, 18... Axis line, 19... Space, 20...
・Central hole, 21...Side hole, 22゜29...One edge, 2
3...free surface, 24...but, 25...valve member,
26... Valve head, 27... Hole, 28... Valve body, 3
0... side. Patent Applicant Lucas Industries Public
Limited FIG, 2゜FIGδ Key FIG, 4゜

Claims (1)

[Scope of Claims] (1) A nozzle body, an inner hole formed in the main body, and a valve member that is operated by fuel pressure and is slidable within the inner hole,
The bore includes a cylindrical portion having an exit hole extending to the exterior of the nozzle body, and the valve member is moved into a space within the nozzle body receiving high pressure fuel when the valve member is moved with pressurized fuel. a cylindrical valve portion slidable within a portion of the bore forming a rim opening the entrance of the bore, the rim forming a rim that connects a wall of the cylindrical valve portion and one of the boundary walls of the space. The angle between the surface and the axis of the hole is such that when the entrance to the hole is only partially open, the fuel flowing into the hole is separated from the circumference and inside the hole. A liquid fuel injection nozzle adapted to form a column of fuel having a free surface for supplying fuel to an internal combustion engine. ■ The nozzle is of the type that opens inward, the space is formed at the end of the cylindrical portion of the inner hole, the valve member has a passage therein for allowing fuel to flow into the space, and the inner hole has a 2. A valve seat as claimed in claim 1, wherein the valve member is configured to engage the valve seat in a closed position to prevent fuel flow through the passageway. nozzle. ■ The circumferential rim is formed by a cylindrical surface of the valve part and another surface formed at the end of the valve member and inclined to the axis of the nozzle by an angle slightly smaller than the angle made by the hole with respect to the axis. A nozzle according to claim 2 formed. (4) The nozzle is of the outward-opening type, the valve member forms a cylindrical valve head opening the entrance of the hole, and the circumference is formed on the cylindrical surface of the valve head and the valve head, perpendicular to the nozzle axis. 2. The nozzle according to claim 1, wherein the nozzle is formed by a flat surface and another surface inclined at an angle slightly smaller than the angle formed by the hole. 6) The nozzle according to claim 3 or 4, wherein the other surface is concentric.