JPH06511064A - Fuel injector for internal combustion engines - 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] Fuel injector for internal combustion engines The present invention relates to a fuel injection valve for an internal combustion engine, the fuel injection valve being connected to an external housing of the injector. a sprayer fixedly placed within the nebulizer, the leading edge of which is closed at the front and has a central hole; The atomizer has a hollow slide valve guide configured as a It has a number of laterally extending nozzle holes for the injection of water, and also opens and closes the nozzle holes. axially displaceable in the guide and supported by a shank at the leading edge. The atomizer hole has a cylindrical end to close the nozzle hole when the valve is in the closed position. a slide valve supported in a tight fit on the injector, the slide having a hole at its end; High pressure fluid flows past the slide valve into the nozzle hole when it assumes the open position exposing the has a flow path that acts against fuel pressure to hold the slide in its closed position. It has a closing spring.

The disclosure of Danish Patent No. 149141 relates to this type of fuel injector, and The id valve and its leading edge that protrudes into the atomizer are relatively rigid laterally; This requires that the slide be mounted completely coaxially with the atomizer hole. vinegar Even the slightest misalignment between the ride and the atomizer hole can cause fuel injector failure. wake up

The rearmost slide valve part supported by the valve guide has a relatively large diameter and is A cutting-edge slide that is ground to size to fit, while plunging into the atomizer hole The valve portion is small in diameter and the cylindrical end is large enough to fit tightly and be supported within the atomizer bore. Polished to perfection. To ensure that the nozzle hole is sealed, immediately before and after the actual fuel injection. Immediately after the fuel pressure in the flow path is extremely high, such as 800 to 1000 bar. The end must fit into the atomizer hole very precisely when reaching the Therefore, the gap between the end and the hole is usually kept at 10 to 20 μm. slide valve There are two requirements for complete coaxiality between the part of the valve guide and the rearmost part supported by the valve guide. is polished in the assembled state, so that the connection between the end and the rest of the slide valve is The shear force generated by the cutting force of the grinder should not cause noticeable bending of the slide valve. It must have great stiffness.

Prior to polishing, the steel slide valve is hardened to a glass solid state. Handling and polishing of slide valves will prevent them from breaking as a result of brittleness. This means that it must be carried out very carefully in order to prevent . This condition, consistent with the strong requirements for concentricity and tolerance of the polished surfaces, The result is that the valve is expensive to manufacture. In addition, when the edges are worn out, the sliding It is inconvenient to have to replace the entire valve. Transportation of slide valves and Replacement is difficult due to the rigidity of the slide, which is why even a slight lateral collision This is because the slide valve may be damaged.

The purpose of the present invention is to provide a longer service life than prior art slide valves, and to The object of the present invention is to provide a slide valve that is easier to replace.

For this purpose, the fuel injection valve according to the invention is characterized in that the axial length of the end of the slide valve is At most, the diameter of the atomizer hole and the shank length should be at least as large as the diameter of the atomizer hole. It is also characterized by being several times longer than the axial length of the end.

Because the end length of the slide valve is short and the shank length is long, the maximum length of the slide valve is The tip is flexible and the atomizer hole automatically aligns with the ride valve relative to its own axis. Align the ends and make the ends fully coaxial with the rearmost slide valve section supported in the valve guide There's no need to do it. Because the end of the slide valve aligns itself with the hole, the end Wear on the ends and the atomizer can be caused by even the slightest misalignment between the end and the atomizer. Reduced compared to prior art injector wear resulting in atomizer infarction and rapid wear do.

It is no longer necessary for the leading and trailing ends of a slide valve to be completely coaxial. In view of the fact that the slide valve is can be done. According to the invention, this means that the cylindrical part of the most advanced part of the slide valve The outer surface of the shape is finally polished to the specified size in addition to the polishing of the sliding part supported by the valve guide. In polishing, it is utilized to facilitate the manufacture of valves. slide valve part By polishing the leading edge to a relatively thin cross-section and the trailing edge to a relatively thick cross-section, each In this assembly, on the one hand, this part does not support the entire weight of the slide valve. Because of this, there is a risk of damage to the advanced glass hardened slide valve part during polishing. On the other hand, since the cutting force is no longer constrained by the cutting-edge slide valve part, Able to use large cutting force to polish thin, thick, and rearmost parts.

According to the invention, when the leading edge sliding part is worn out and has to be replaced, Only the advanced slide valve part including the shank and end can be replaced; The rearmost slide valve section can be left installed, which allows for replacement. This greatly reduces the expense incurred by can be made into something.

The life of the slide valve is determined by the fact that at least the leading edge of the cylindrical outer surface of the end is stellite. This is further extended by a preferred embodiment made of a corrosion resistant material such as No. 6. Endurance The erodible material is used when the end opens the nozzle hole by opening the injector, and when the fuel Reduces end tip wear that occurs when flow begins at very high speeds through the nozzle hole. Ru. The large flow velocity that occurs immediately after the valve opens near the tip of the end is caused by a large pressure negative. Add it to the top. Corrosion-resistant materials are capable of supporting said loads, thereby , extend the life of the slide valve.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an axial sectional view of an embodiment of the injection valve with the slide valve shown in the open position; be.

Figure 2 shows the most advanced portion of the injection valve shown in Figure 1 with the slide valve shown in the closed position; FIG. 2 is an enlarged axial cross-sectional view of FIG.

FIG. 3 is a side sectional view of the most advanced portion of the slide valve.

4 is a cross-sectional view of the slide valve along IV-IV in FIG. 3. FIG.

FIG. 5 is an axial sectional view of the distal end portion of the second embodiment of the injection valve.

FIG. 6 is a cross-sectional view of the most advanced portion of the slide valve taken along the line Vl-Vl in FIG. 5. .

The fuel injection valve shown in Figures 1, 2 and 5 is a long one with a head 2 at its rearmost end. It has an outer housing 1 and the injection valve has a head 2, as is known, in an internal combustion engine. It is attached to the cylinder cover and connected to a fuel pump (not shown). Hehe The door 2 has a fuel oil inlet 3 which is supported by a central thrust piece 5 and a valve housing 7. The rearmost end of the valve housing 7 communicates with the conduit 4 which extends through the valve member 6 which is It contacts the piece 5 at its forward shoulder and its leading edge touches the corresponding conical surface of the valve guide 8. The valve guide 8 has a contacting conical surface, and the valve guide 8 fits tightly into the housing 1 at its rearmost end and At its leading edge, when the injection valve is installed on the cylinder cover, the housing 1 is passed through. This supports a sprayer that enters the combustion chamber of an engine cylinder (not shown).

A slide valve, generally indicated by the reference numeral 10, is axially variable within the valve guide 8. having a rearward end portion 11, the cylindrical outer surface of which is ground to size; and is tightly fitted and supported in the center guide hole of the valve guide 8. The sliding part 11 is the frontmost part 1 1, and has a forward-most sliding portion 12 that is considerably thinner than 1 and that plunges into the central hole 13 of the atomizer. I support it.

A central tube 14 extending into the rearmost portion of the slide valve is integral with the valve guide 8 and It has a forward facing shoulder which restrains the backward movement of the door valve 10.

Contacting the valve guide 8 rearwardly and forwardly facing the rearwardly facing shoulder 17 of the rear end of the slide valve portion 11 A closing spring 16 in contact with the valve guide is received in the hollow space 15 of the valve guide and is in contact with the closing spring 16. Therefore, the slide valve is loaded forward in the direction toward the closed position shown in FIG. ing.

The inlet conduit 4 communicates with the flow path 19 through the side hole and the adjacent valve seat 18, and the flow path 19 reaches the distribution chamber 20 provided in the slide valve at the front, and the distribution chamber 20 passes through the side hole 21. which communicates with an annular chamber 22 defined between the outside of the slide valve and the peripheral portion of the valve guide. I'm passing through. A conical seat 23 is formed in the valve guide 8 at the leading edge of the chamber 22 and is A conical seat 24 corresponding to the tip of the portion 11 is provided on the devalve, and the conical seat 24 is connected to the injection valve. In the closed position, the closing spring 16 presses against the seat 23 and makes a seal. Ru.

The most advanced part 12 of the slide valve has a central hole at the most advanced part of the slide valve part 11 at its rear end. a threaded portion 25 that is screwed into the rear shoulder portion 26 of portion 12; come into contact with. Safety inserted through a series of holes in slide valve parts 11 and 12 The pin 27 prevents the leading edge from rotating unexpectedly away from the trailing edge 11. prevent.

Safeguards against this separation can be achieved using other methods such as Loctite®. It can also be implemented with adhesive. The shoulder 26 has a relatively thin and long shoulder in front. Continuing with the shank 28, the leading edge of which is a cylindrical outer surface that is supported in a tight fit within the bore 13 of the atomizer. It is supported by an end 29 with 30.

The wall of the atomizer is provided with a number of laterally extending nozzle holes 31, and the injection valve is closed as shown in FIG. When in the chained position the end 29 closes the nozzle hole, while in the open position of the injector (Fig. ), the end 29 is moved rearwardly enough that the nozzle hole is completely exposed. Placed.

When the valve member 6 contacts the valve seat 18, preheated oil is sprayed over the side hole of the thrust plate 5. The flow through the injection valve heats the valve. Fuel oil pressure at inlet 3 increases prior to the start of injection 1, the valve member 6 is moved rearward to the position shown in FIG. The circulating oil is blocked from passing through, and the flow then directs the fuel oil through the valve seat and down one passage. and is discharged into chamber 22, where the pressure of the ura is increased by closing spring 16. the slide valve rises until it overcomes the applied force, and the slide valve returns from the closed position shown in Figure 2. be moved towards

Immediately after seats 23 and 24 are separated, fuel oil flows forward into the space surrounding shank 28. and passes through a groove 32 forming part of the hole 13 located in front of the end 29. End 29 extends a distance forward through the nozzle 631 in the closed position of the injector. Therefore, pressure builds up in the fuel oil in front of the end 29 prior to exposure of the nozzle hole. , which means that the fuel oil is injected with full pressure almost from the beginning of injection, thereby This means that combustion will definitely improve.

The leading end portion 12 and the trailing end portion 11 of the slide valve are connected to the slide valve 10 in the injection valve. It is an off-the-shelf product, like two separate units that are assembled immediately before installation. comparison The thick slide valve section 11 allows for large cuts due to its high stiffness against lateral bending. Processed by cutting force.

The leading edge part 12, in the embodiment shown in FIGS. 2.3 and 4, consists of two elements. , i.e., a shank 28 and a ring made of a corrosion-resistant material such as Stellite 6. It consists of 33. The shank 32 has a large diameter at its tip and a circumference. The fuel oil is distributed along the ring 33, yet allows the fuel oil to pass through the ring 33 as described above. It has a longitudinal groove 32 to make it. Grooves 32 are arranged in three radial directions at the leading edge of the shank. The ring 33 is made of, for example, hard wax, leaving a lobe 34 protruding in the direction. Fixed by connection. Alloy 50 is used as a wax. This slide valve cutting edge The three-part configuration of the parts is extremely suitable for mass production, with the ring 33 and the shank 28 can be easily manufactured by automatic numerical control processing. If suitable If so, the shank should of course have three or more radially projecting lobes. It can also be configured as follows.

If only the slide valve tip 12 of small dimensions is manufactured, then FIGS. A suitable configuration is as shown in FIG.

The leading edge is made from a single piece of steel material at the leading edge and is supported in the atomizer hole. Manufactured at a distance to the side corresponding to the planned surface, such as Stellite 6 A corrosion-resistant layer is welded on. The shoulder 26 and shank 28 are manufactured by turning; A central hole 35, longer than the cylindrical end 29, is drilled from the tip of the stock. End 29 rear a portion of the shank 28 that is located at and has a smaller diameter than the end 29 but is located rearward The larger diameter portion 36 of the shank is then slightly smaller than the wall thickness of the annular end 29. A suitable number, e.g. four, longitudinal grooves 37 are provided with a large radial depth; A groove 37 discharges into the hole 35 and connects each of the atomizer holes located rearward and forward of the end 29. Provide fluid communication between the parts. As a final treatment of the advanced slide valve, the end 29 The outer surface of is polished to the desired dimensions.

The flow path that allows combustible material to flow past the slide valve is shown in Figure 2. The channel has grooves 32 in the embodiment shown in FIG. and a hole 35.

Instead of the illustrated screw assembly between the two extreme positions, each part could of course be assembled in a different way, e.g. For example, they can be assembled by press-fitting or similar joining means. Ru.

The shank may be connected in other ways, for example by connecting the rearmost part of the shank to the end. It can be constructed in other ways, such as with a large number of parallel thin rods. To the present invention The essential feature of the shank is that it supports the rearmost sliding valve portion of the valve guide 8. Its flexibility allows it to match the hole 13.

n/36 F/6.5 Submission of translation of written amendment (Article 184-8 of the Patent Law) March 1994, 3rd reprimand

Claims (1)

[Claims] 1. It is fixedly arranged in the outer housing (1) of the injection valve, and its leading edge is Hollow slide configured as an atomizer (9) closed and with a central hole (13) The atomizer has a plurality of valve guides (8) on its side wall for the injection of atomized fuel. It has a nozzle hole (31) extending in the horizontal direction, and a guide inside for opening and closing the nozzle hole. axially displaceable and supported by a shank (28) at the most extreme part (12) cylindrical end (29) for closing the nozzle hole when the valve is in the closed position. a slide valve (10) hermetically supported in a hole (13) of the sprayer; The injection valve emits high pressure flow when the slide assumes an open position with its end (29) exposing the hole. A flow path (3, 4, 19) in which the body passes through the slide valve (10) and flows into the nozzle hole (31). , 21, 13; 32) and a fuel supply to hold the slide in its closed position. In a fuel injection valve for an internal combustion engine having a closing spring (16) acting against pressure, The axial length of the end (29) of the slide valve (10) is at most The length of the shank (28) is at least as large as the diameter of the shank (28). ) A fuel injection valve for an internal combustion engine characterized by being several times longer than the length of the fuel injection valve. 2. The end (29) is a cylindrical ring (33) fixed to the shank (28) The fuel injection valve for an internal combustion engine according to claim 1, characterized in that: . 3. At its ring-facing end, the shank (28) preferably has at least three radially extending lobes (34) with a ring (33) thereon, preferably 3. The fuel for an internal combustion engine according to claim 2, wherein the fuel is fixed by soldering. fuel injection valve. 4. The shank (28) and the end (29) are made from one piece of material; ) its ends forming a central hole of the atomizer located above the end in the area above the end Claim 1 characterized in that it has a central hole (35) communicating with the part (13). A fuel injection valve for an internal combustion engine as described in . 5. At least the leading edge of the cylindrical outer surface (30) at the end is like a stellite 6. According to any one of claims 1 to 4, the material is made of a corrosion-resistant material. Fuel injection valve for internal combustion engines. 6. The most advanced portion (12) of the slide valve including the shank (28) and end (29) ) is characterized in that it can be replaced as one piece independently of the rest of the slide valve. The fuel injection valve for an internal combustion engine according to any one of claims 1 to 5. 7. The cylindrical outer surface of the distal end portion (12) of the slide valve is ultimately supported on the valve guide. It is characterized by being polished to dimensions unrelated to the polishing of the slide portion (11). The slide valve of a fuel injection valve for an internal combustion engine according to any one of claims 1 to 6. method used in manufacturing.