KR20120004911A - A fuel injector for internal combustion engines - Google Patents

Abstract

PURPOSE: A fuel injector for an internal combustion engine is provided to prevent fuel flow from being disturbed because a cut-off element is guided under a lower group of inlet openings and above lower sealing parts. CONSTITUTION: A fuel injector for an internal combustion engine includes an atomizer(10) which has a vertical bore(14) and multiple nozzle bores(16). Inlet openings(18) of the nozzle bores are separated a lower group and an upper group and they are separated from a vertical axis(A). A cut-off element(22) of the atomizer is extended into the vertical bore and vertically moves between an opening position and an closed position. The vertical bore and the cut-off element respectively have upper and lower sealing parts(24,28,26,30) and form upper and lower cut-off planes(32,34) by cooperating with each other in a location where the cut-off element is closed. The upper and lower cut-off planes are extended to above the upper group and under the lower group of the inlet openings. Fuel flows through inside the location where the cut-off member is opened.

Description

Fuel injection machine for internal combustion engines {A FUEL INJECTOR FOR INTERNAL COMBUSTION ENGINES}

The present invention relates to a fuel injector for an internal combustion engine. The invention relates in particular to fuel injectors for large two-stroke internal combustion engines, such as marine propulsion diesel engines.

More specifically, the present invention relates to a fuel injector according to the preamble of claim 1, wherein the fuel injector comprises: an atomizere provided with a plurality of nozzle bores and fixed to the lower end of the valve guide; ; A spindle having a valve portion cooperating with a valve seat of the valve guide; And a cut-off element fluidly connected with the nozzle bores when the spindle is in the closed position to extend into the longitudinal bore of the nebulizer to reduce the volume.

EP-A-052937 discloses a fuel injector comprising an axially movable spindle having a valve portion cooperating with a corresponding valve seat of a valve guide and a blocking member extending into the central bore of the sprayer below the valve portion of the valve spindle. have. The outer wall of the blocking member is effective for opening and closing the inlet openings of the nozzle bore.

In the solution disclosed in EP-A-052937, the nozzle bores are arranged in a line, which means that the inlet openings of the nozzle bores are all arranged at approximately the same distance from the lower end of the sprayer. One problem with this solution is that the total number of nozzle bores arranged within the maximum angle cannot be increased without matching the strength of the side walls of the sprayer.

WO2008 / 071187 discloses a fuel injector according to the preamble of claim 1, wherein the inlet openings of the nozzle bores of the sprayer are first row and second row axially away from the first row. rows) and are separated from each other by cylindrical seals. The blocking member extending into the longitudinal bore of the sprayer has a cylindrical first cross section arranged to open and close the lower row of inlet openings and a cylindrical cooperating with the second valve seat to close the upper row of inlet openings when the valve spindle is closed. Has a second cross section.

When the valve spindle opens, the lower row of inlet openings is supplied with fuel flowing through the central duct of the blocking member and the upper row of inlet openings flows in an annular passage formed between the outer surface of the blocking member and the inner wall of the sprayer bore. Fuel is supplied.

One problem with the solution disclosed in WO2008 / 071187 is that the blocking member is not guided completely in the open position of the spindle. Thus, during the closing stage of the spindle, when the blocking member is moved downwards, there is a possibility that the edge of the blocking member is hit against the sprayer wall. This is caused by fluid dynamic forces acting on the blocking member at the injection hole height. This force can push the blocking member towards the injection holes and even cause the blocking member to bend.

It is an object of the present invention to provide an improved fuel injector design that solves the problems caused by the hydrodynamic forces acting on the obstruction member.

According to the invention this object is achieved by a fuel injector having the features of claim 1.

Other features and advantages of the present invention will become apparent from the detailed description provided hereinafter by way of purely non-limiting example with reference to the accompanying drawings.

1 shows a part of an axial cross section of a nebulizer according to a first embodiment of the invention.
2 shows a part of a cross section of a second embodiment of the invention.
3 and 4 show part of a cross section of a third embodiment of the invention in the open and closed positions, respectively.

1, the lower part of a fuel injector atomizer for a diesel engine is indicated by reference numeral 10.

In the following description and claims, the terms "top", "bottom", "top", "bottom" and similar terms refer to the normal position when using the fuel injector. However, it should also be taken into account that the fuel injector 10 can be mounted in a slightly inclined position with respect to the vertical axis.

The sprayer 10 consists of a cylindrical body of corrosion resistant material having a closed round bottom end 12.

The sprayer 10 has a longitudinal bore 14 with a longitudinal axis A and closed at the bottom end. A plurality of nozzle bores 16 are formed on the lateral wall of the sprayer 10. The nozzle bores 16 each have inner openings 18 facing into the longitudinal bore 14 and outlet openings that are open on the outer surface of the sprayer 10. The inlet openings 18 of the nozzle bore 16 are divided into upper and lower groups which are spaced apart from each other in the longitudinal direction A. FIG.

The fuel injector includes a spindle (not shown in FIG. 1) with a blocking member 22 extending into the longitudinal bore 14 of the sprayer 10.

The blocking member 22 is movable in the longitudinal direction A with respect to the longitudinal bore 14 between the open position and the closed position.

The longitudinal bore 14 has cylindrical upper and lower seals 24, 26. The upper seal 24 is above the upper group of inner openings 18 and the lower seal 26 is below the lower group of inner openings 18.

The blocking member 22 has a cylindrical upper seal 28 and a cylindrical lower seal 30. In the closed position, the upper and lower seals 28, 30 of the blocking member 22 are in sealing contact with the upper and lower seals 24, 26 of the longitudinal bore 14, respectively. The blocking surface 32 and the lower blocking surface 34 are formed.

In the open position shown in FIG. 1, the upper and lower seals 28, 30 of the blocking member 22 axially with respect to the upper and lower seals 24, 26 of the longitudinal bore 14. It is offset. In this position, the upper and lower blocking surfaces 32, 34 are open. The lower seal 30 of the blocking member 22 is located between the upper group and the lower group of the inner openings 18.

The blocking member 22 is in a central duct 36 in fluid connection with the longitudinal bore 14 above the upper blocking surface 32 and below the lower blocking surface 34 in the closed position of the blocking member 22. )

The blocking member 22 is provided with an additional guide cross section 38 extending under the upper seal 28 of the blocking member 22. The further guide cross section 38 is in guiding contact with the upper seal 24 of the longitudinal bore 14.

The further guide cross section 38 comprises a plurality of guide ribs 40 having cylindrical outer surfaces in sliding contact with the upper seal 24 and spaced apart from each other in the peripheral direction. Channels 42 are formed between the guide ribs 40 adjacent to each other. The channels 42 allow fuel to flow through the upper blocking surface 32 in the open position of the blocking member 22.

In the open position of the blocking member, fuel under pressure flows into the annular channel formed between the inner surface of the longitudinal bore 14 and the outer surface of the blocking member 22. First fuel flows through the channels 42 to reach the upper group of inner openings 18. Second fuel flows into the axial duct 36 of the obstruction member 14 to reach the lower group of inner openings 18. In the open position, the guide ribs 40 are in contact with the upper seal 24 of the sprayer 10. The guide ribs 400 eliminate the risk of impact between the inner wall of the sprayer and the blocking member due to the hydrodynamic forces acting on the blocking member 22. Between the blocking member 22 and the longitudinal bore 14 Clearance is kept to a minimum, thereby reducing fuel outflow.

2 shows an alternative embodiment, wherein the lower seal 30 of the blocking member 22 extends below the lower group of inner openings in the closed and open positions of the blocking member 22.

In the open position shown in FIG. 2, the entire fuel flows in the downward direction through the upper sealing cross section 32 toward the upper and lower groups of the inner opening 18. All injection holes 16 are supplied with fuel flowing out of the blocking member 22. In this way the pressure drop of the fluid is limited because there is no need to greatly limit or change the flow in the flow direction.

In order to prevent the fuel flow supplied to the injection hole from becoming unstable, the blocking member is guided above the lower seal 30, under the lower group of the inner openings 18.

In the embodiment of FIG. 2, since there is no need to drill a relatively large hole on the blocking member 22 and only small holes will be needed to balance the pressure on the end face of the blocking member, the blocking member The manufacturing process of (22) is simple. No holes greater than 35% of the diameter of the blocking member 22 are formed. In this way, the barrier member 22 is subjected to much less stress than the prior art design, thus increasing the stability of the components. The design also provides very high sac volume reduction.

3 and 4 show yet another solution for closing injection holes with almost zero shock volumes without any radial force caused by fluid flow kinetics where friction may occur between the nozzle wall and the valve body. To show.

The blocking member is designed as a pipe and a spherical member 44 such as a ball is positioned above the bottom end of the longitudinal bore 14. In the closed position, the bottom end of the blocking member 22 abuts on the spherical member 44 and blocks the main flow on the sealing surface of the spherical member 44.

An elastic disk 46 is provided at the upper end of the longitudinal bore 14 to block outflow into the cylinder through the gap between the longitudinal member 14 and the obstruction member 22. The spindle 48 is provided with a conical seal 50 over the blocking member 22. The sealing area between the conical seal 50 and the disk 46 is closed at the same time the bottom end of the blocking member 22 is in contact with the spherical member 44.

Although not shown in the drawings, the embodiments of FIGS. 2, 3 and 4 may have a driver guide portion 38 as described with reference to FIG. 1.

Claims (7)

A fuel injector for an internal combustion engine, the fuel injector:
A sprayer 10 having a longitudinal bore 14 and a plurality of nozzle bores 16 with inlet openings 18 directed into the longitudinal bore 14, the inlet openings 18 being longitudinal Divided into upper and lower groups which are spaced apart from each other in the direction (A),
A blocking member 22 extending into the longitudinal bore 14 of the nebulizer 10, the blocking member 22 being longitudinal relative to the longitudinal bore 14 between an open position and a closed position. Moveable in direction A,
The longitudinal bore 14 and the blocking member 22 have upper and lower seals 24, 28, 26, 30, respectively, which cooperate with each other in the closed position of the blocking member 22 to be upper and lower. Internal barriers extending above the upper group of inlet openings 18 and below the lower group of inlet openings 18, respectively, forming upper and lower blocking surfaces 32 and 34, respectively. In the engine fuel injector,
The blocking member 22 is provided with an additional guide cross section 38 in guiding contact with the upper seal 24 of the longitudinal bore 14 and in the open position of the blocking member 22. Fuel injectors for internal combustion engines that allow fuel to flow through it. The method of claim 1,
The further guiding cross section 38 defines the cylindrical outer surfaces in sliding contact with the cylindrical upper seal 24 of the longitudinal bore 14 in the open position of the blocking member 22. A fuel injector for an internal combustion engine, characterized in that it comprises a plurality of guide ribs (40) having. The method of claim 2,
The guide ribs (40) are fuel injectors for internal combustion engines, characterized in that they are separated from one another in the peripheral direction by channels (42) to allow fuel to flow through. The method of claim 1,
The lower seal (30) of the blocking member (22) in the open position of the blocking member (22) extends between an upper group and a lower group of inner openings (18). The method of claim 1,
A lower injection portion (30) of the blocking member (22) in the open position of the blocking member (22) extends under a lower group of inner openings (18). The method of claim 1,
The shutoff member (22) has a bottom end in contact with the spherical member (44) in a closed position in a closed state. The method of claim 6,
A deformable disk 46 is provided at the upper end of the longitudinal bore 14 and a conical seal 50 is provided at the upper end of the blocking member 22, and the conical seal 50 is provided at the blocking end. A fuel injector for an internal combustion engine, characterized in that it is against the deformable disk (46) in the closed position of the member (22).

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