KR100717526B1 - Fuel-injection valve - Google Patents

Abstract

The present invention relates to a fuel inlet (7), a movable valve closing member (28), one stationary valve seat (27) that interacts with the valve closing member (28) for opening and closing the valve, and a downstream valve end (8). Fuel injection valve 5, in particular the combustion chamber of the internal combustion engine, wherein the fuel discharge portion is formed by at least one discharge port 32, 90 disposed downstream of the valve seat 27; A direct injection fuel injection valve. The valve seat member 26 comprising at least one outlet 32 includes a coating layer at least in the opening region 55 of the outlet 32 of the downstream end face 54 to prevent coking in that region. .

Fuel inlet, valve closing member, valve seat, outlet, opening area, combustion chamber, downstream surface

Description

Fuel-injection valve

The present invention relates to a fuel injection valve according to the preamble of the independent claim.

During engine operation, in general, when directly injecting fuel into the combustion chamber of an internal combustion engine, the downstream peak of the injection valve protruding into the combustion chamber, especially during direct injection of gasoline or diesel fuel, is coked by the deposition of fuel, or The soot particles formed on the flame surface accumulate at the valve peak. Therefore, in the injection valves projected to the combustion chamber, which are known so far, the risk of adversely affecting the injection parameters (e.g. static flow rate, injection angle, drop size, multiple) during their lifetime, i.e. failure of the internal combustion engine or failure of the injection valve There is a risk of failure.

The fuel injection valve according to the invention with the features of the independent claims has the advantage of reducing or eliminating the negative effects of coking (soot deposition) of valve peaks protruding into the combustion chamber. Coking or stratification (soot) at the valve end is reduced, which negatively affects injection parameters and valve function, in particular by coating according to the invention at the downstream valve end, in particular those around the opening area of the outlet, or It stops.

The measures set out in the dependent claims enable the implementation and improvement of the fuel injection valves set out in the independent claims.

It is desirable to provide layers at the valve end that cause catalytic conversion (combustion) of the deposit or reduce surface energy and / or surface roughness of the part to be coated. This changes the wet state or prevents the formation of the reaction layer.

Embodiments of the present invention are briefly shown in the drawings and described in more detail in the following description.

1 is a fuel injection valve inserted into the receiving hole of the cylinder head.

2 is a longitudinal sectional view of a fuel injection valve;

3 shows a first embodiment of a valve end coated according to the invention.

4 shows a second embodiment of a valve end coated according to the invention.

5 shows an alternative guide and seat area at the injection side valve end.

6 is a longitudinal sectional view of a fuel injection valve for a compression ignition type internal combustion engine;

7 is a combustion chamber side end of the fuel injection valve according to FIG. 6;

1 shows a cylinder head 1 of an internal combustion engine, in particular a mixer compression type, externally ignited internal combustion engine. The cylinder head 1 is formed with a stepped accommodation hole 2 extending symmetrically along the longitudinal axis 4 to the combustion chamber 3. The fuel injection valve 5 according to the present invention is inserted into the accommodation hole 2 of the cylinder head 1. The fuel injection valve 5 is used to inject fuel, in particular gasoline or diesel, directly into the combustion chamber 3 of the internal combustion engine, as shown by FIGS. 6 and 7. The fuel injection valve 5 can in particular be electromagnetically operated via the electrical connection cable 6. Fuel is supplied to the fuel injection valve 5 via the inlet pipe 7. The fuel injection valve 5 shown in FIG. 1 is a so-called Top-Feed-injection valve which axially directs fuel from the inlet pipe 7 through the entire injection valve 5, wherein the fuel is supplied to the supply side. It is injected into the fuel chamber 3 at the injection side end 8 lying opposite to the end.

In order to protect the fuel injection valve 5 near the combustion chamber 3 from overheating, the injection valve 5 is at least partly enclosed, for example, by a heat dissipation sleeve 9 mounted in the receiving hole 2, for example. There may be no heat dissipation sleeve.

In figure 2 an embodiment of a fuel injection valve 5 according to the invention is shown in cross section. The fuel injection valve is an electromagnetically actuated valve having a hollow cylindrical core 11 at least partly wound with a magnetic coil 10 and used as the inner pole of the magnetic circuit and shaped as a pipe. For example, a stepped coil body 13 made of plastic receives a winding of the magnetic coil 10 and has a magnetic coil (along with a non-magnetic intermediate portion 14 in which the core 11 and the magnetic coil 10 are partially wound). It allows the construction of a very compact and short injection valve in the area of 10). Instead of the electromagnetically actuated element, the fuel injection valve 5 can be operated piezoelectrically or magnetostrictively.

The core 11 is provided with a longitudinal opening 15 extending along the valve longitudinal axis coinciding with the longitudinal axis 4 of the receiving hole 2. The core 11 of the magnetic circuit is also used as the inflow pipe 7. The outer metal (eg ferrite) housing part 16 which closes the magnetic circuit as an outer conductive element or an external conductive element and completely surrounds the magnetic coil 1 at least in the circumferential direction has a core 11 on the upper portion of the magnetic coil 1. Is firmly connected. The longitudinal opening 15 of the core 11 is provided on the supply side with a fuel filter 17 for filtering fuel components which, due to their size, may clog or damage the injection valve.

For example, the lower housing portion 18 in the form of a pipe comprises or receives an axially movable valve portion or an elongated valve seat support 21 comprising an armature 19 and a bar-shaped valve needle 20. The upper housing portion 16 is firmly connected in a sealed manner. The two housing parts 16, 18 are firmly connected to one another, for example by means of an enclosing weld seam. The sealing between the housing portion 18 and the valve seat support 21 is made, for example, by a sealing ring 22. The valve seat support 21 includes an internal through hole 24 extending concentrically with the valve longitudinal axis throughout its axial width.

The lower end portion of the valve seat support 21, which is also the downstream end of the entire fuel injection valve 5, has a truncated valve seat surface of a truncated cone shaped valve seat member 26 inserted into the through hole 24 downstream. Wrap in (27). A valve needle 20 having a valve closing section 28 at the downstream end is arranged in the through hole 24. For example, a spherical, partially spherical or conical tapered valve closing section 28 acts in conjunction with a valve seat face 27 disposed on the valve seat member 26 in a known manner. At least one fuel outlet 32 is formed in the valve seat member 26 downstream of the valve seat surface 27.

Guide openings 34 provided at the end toward the armature 19 on the valve seat support 21, on the one hand for guiding the valve needle 20 during axial movement with the armature 19 along the valve longitudinal axis. On the other hand, a plate-shaped guide member 35 disposed upstream of the valve seat member 26 is used, which includes a guide opening 36 of correct dimensions.

The stroke of the valve needle 20 is predetermined by the assembly position of the valve seat member 26. One final position of the valve needle 20 is determined by contacting the valve closing section 28 with the valve seat surface 27 of the valve seat member 26 when the magnetic coil 10 is not excited, while the valve needle ( Another final position of 2) is given by the armature 19 contacting the downstream end face of the core 11 when the magnetic coil 1 is excited. The surface of the part in the latter stationary region is for example chromium plated.

Electrical contact of the magnetic coil 1 and thus excitation of the coil is made through a contact member 43 having a plastic extrusion 44 on the outside of the coil body 13. The plastic extrusion 44 can extend over other parts of the fuel injection valve 5 (eg housing portions 16, 18). An electrical connection cable 6 extends from the plastic extrusions 44, and current is supplied to the magnetic coil 10 through the cable.

The guide area and the seat area provided in the through hole 24 of the support at the injection side end of the valve seat support 21 are composed of three plate-shaped members separated in function in the axial direction. In the downstream direction, the guide member 35, the pivot member 47 and the valve seat member 26 are followed. The compression spring 50 surrounding the valve needle 20 secures the three members 35, 47, 26 to the valve seat support 21. The pivot member 47 can be inexpensively manufactured, for example, by punching into thin sheets, by wire EDM, laser cutting, etching or other known methods or by galvanic deposition. The pivot member 47 is provided with one inner pivot chamber and a plurality of pivot channels leading to the pivot chamber. In this way, a swirling component is added to the fuel to be injected in front of the valve seat 27 so that the flow enters the outlet 32 as the flow turns, providing a finely swirled and well sprayed spray to the combustion chamber 3.

During engine operation, when the fuel is injected directly into the combustion chamber of the internal combustion engine, the downstream peak of the injection valve, which protrudes into the combustion chamber, is often burned by fuel deposits or soot particles formed on the flame surface accumulate on the valve peak. Occurs. Thus, injection valves protruding into the combustion chambers known to date are subject to injection parameters (e.g. static flow rate, injection angle, droplet size, multiple), which may lead to failure of the internal combustion engine or failure of the injection valve during its lifetime. There is a risk of adverse effects on the body.

The problem is reduced or eliminated by providing a coating layer at the valve end 8 according to the invention. By the various coating layers, various effects are obtained on the surface 54 of the coated part, for example, the valve seat member 26 made of chrome steel. However, all measures aim to reduce or prevent coking or layer formation (soot) at the valve end 8 which in turn generally negatively affects the injection parameters and valve function. The individual coating methods are described in detail below.

Catalytic layers form the first coating group. The layers provided by electrolysis allow for catalytic conversion (burning) of the deposited soot particles or prevent deposition of carbon particles from scratch. Suitable materials for the coating for anti-coking are oxides of cobalt oxides, nickel oxides and alloys of the metals. Precious metals Ru, Rh, Pd, Os, Ir, Pt or alloys with one another or with other metals also catalyze. Certain layers are formed through, for example, metal precipitation without electrochemical or external currents. In the case of Ni, Co, or alloys thereof, oxide formation or additional oxidation steps (wet chemical treatment, plasma) in air can be applied.

Coating layers that vary the wettability of the surface 54 form a large second group. The coating can then reduce the surface energy and / or surface roughness of the critical region of the valve end 8. This increases the interface energy between the surface 54 and the fuel, so that wetting deteriorates. The fuel droplets thus flow under the coating even if they fall away from the coated area according to the invention and are swept by the surrounding flow of the valve end 8. Permanent wetting of the valve end 8 no longer occurs. As the layer, a ceramic layer, a carbon layer containing or not containing a metal, or a fluorine-containing layer is provided. The fluorine-containing layer is for example a heat resistant PTFE-like layer or in particular an organic ceramic layer, or an Ormocer® layer made of so-called fluorine silicate (FAS). The fluorine-containing layers are provided, for example, by spraying or dipping. Sapphire layers are also possible.

A coating layer capable of preventing the reaction layer forms the third group. For example, nitride layers (TiN, CrN) and oxide layers (tantalum oxide, titanium oxide) belong to this. Similar to sputtering, in this layer, the evaporated particles are deposited on the surface 54 to be coated.

At the valve end 8, in particular, an area which directly encloses at least one outlet 32 in its adjacent opening area 55 can be coated. The deposition of soot particles at the outlet 32 or adjacent limiting edges of the outlet results in particular the above mentioned negative effects of the spray parameters (eg static flow rate, spray angle, droplet size, multiple). That is, in all cases the coating should be carried out at the downstream end (opening area) 55 of each individual outlet 32 regardless of which part of the fuel injection valve 5 is formed.

3 and 4 two embodiments of the valve end 8 coated according to the invention are shown in a bottom view. The two embodiments are in one case coated with a part having an outlet 32, in this case the entire downstream part surface 54 of the valve seat member 26 (FIG. 3), in other cases with at least one outlet 32. The only difference is that the annular portion of the downstream component surface 54 around () is coated (FIG. 4). The dotted side shows the coated area. The opening area 55 of the outlet 32 lies in the projection plane in FIGS. 3 and 4. It is important that a coating layer be provided at the outlet 32 as well.

In the illustrated embodiment the valve seat member 26 is part of the fuel injection valve 5 which forms the downstream end 8 and comprises the outlet 32, so that the downstream end face of the valve seat member 26 is Coating may be performed on 54. However, the provision of the coating layer according to the invention is not limited to the valve seat member, but rather other valve parts which protrude into the combustion chamber 3 by forming the downstream valve end 8 may also have the coating layer. It is also applied to components arranged downstream of the valve seat 27 (see injection body 67 in FIG. 5) that at least the area directly adjacent the outlet 32 is coated so that the original injection area is protected from coking.

In Fig. 5 an alternative guide area and seat area of the injection side valve end 8 is shown to clarify that the description of the coating according to the invention also applies to structurally different valve designs. In this embodiment, another plate-shaped injection body 67 is arranged downstream of the valve seat member 26. In this case the injection body 67 has an outlet 32. The outlet 32 is inclined obliquely with respect to the valve longitudinal axis and ends in the convex arcuate injection zone 66. The injection body 67 and the valve seat member 26 are firmly connected to one another via a welding seam 68 obtained, for example, by laser welding, which welding is carried out in an annular enclosed groove 69. In addition, the injection body 67 is firmly connected to the valve seat support 21 through the welding seam 61. The coating is made annular, for example, directly over the entire arcuate spray area 66 or around the opening area 55 of the outlet 32, so that a coating layer off-centered at the arcuate surface 54 with respect to the valve longitudinal axis is provided. do.

6 shows a longitudinal section of a compression ignition internal combustion engine, in particular a fuel injection valve for a diesel engine, with only the part facing the combustion chamber. An enlarged view of the combustion chamber side end portion of the fuel injection valve 5 shown in FIG. 6 is shown in FIG. 7. The part formed of the valve body 72 is fixed with respect to the valve fixing body 73 with the tension nut 75. In the valve body 72, one bore 84 is formed in which a valve-shaped valve needle 20 which moves axially against the closing force is arranged. The bore 84 is formed as a pack bore and forms a valve seat surface 27 formed in a substantially truncated conical end to the combustion chamber. The pack hole 92 is formed through the depression of the combustion chamber side end part of the valve seat surface 27, and the at least one discharge port 90 which connects the said pack hole 92 with the combustion chamber 3 is arrange | positioned at the wall of the said hole. do.

The valve needle 20 is divided into a larger diameter section and a smaller diameter section placed opposite the combustion chamber 3, which are guided to the bore 84. A pressure chamber 86 is formed between the small diameter section and the wall of the bore 84. The pressure chamber may be filled with high pressure fuel through the valve holding body 73 and the supply channel 80 formed in the valve body 72. The stepped formation of the outer diameter of the valve needle 20 forms a pressure shoulder 82 on the valve needle. The pressure shoulder 82 is disposed inside the pressure chamber 86. The fuel pressure in the pressure chamber 86 generates a force on the pressure shoulder 82. The force component acting axially is the opposite of the closing force acting on the valve needle 20 and moves the valve needle 20 against the closing force at a corresponding fuel pressure.

At the combustion chamber side end of the valve needle 20 is formed a valve sealing surface 88 which forms a valve closing section 28. The valve sealing surface interacts with the valve seat surface 27 such that the valve sealing surface 88 contacts the valve seat surface 27 such that the at least one outlet 90 is sealed against the pressure chamber 86. The valve sealing surface 88 is lifted from the valve seat surface 27 and connects the pressure chamber 86 with the outlet 90 through an open-stroke movement away from the combustion chamber 3 to the inside.

A catalytic coating layer is provided throughout the end face of the valve body 72, for example facing the fuel chamber 3. The coating layer may be provided only on the arcuate outer surface 96 of the packhole wall 93 in contact with the packhole 92, in which at least one outlet 90 is formed. In addition, the coating layer may continue up to the outlet 90.

Claims (15)

Fuel discharge formed at the fuel inlet 7, the movable valve closing member 28, the fixed valve seat 27 interacting with the valve closing member 28 for opening and closing of the valve, and the downstream valve end 8. And a fuel outlet comprising at least one outlet (32, 90) disposed downstream of the valve seat (27) and comprising at least one outlet (32, 90). In the fuel injection valve (5), wherein 72 includes a coating layer surrounding the outlet at least in the opening area 55 of the outlets 32, 90, The coating layer is a fuel injection valve, characterized in that the form of a fluorine-containing layer which is a layer consisting of fluorosilicate (FAS). delete delete 2. The fuel injection valve according to claim 1, wherein the fuel injection valve projects into the combustion chamber (3) of the spark ignition type internal combustion engine. The fuel injection valve according to claim 1, wherein the fuel injection valve projects into the combustion chamber (3) of the compression ignition type internal combustion engine. 6. The coating as claimed in claim 1, 4 or 5, wherein the coating layer is annular around the outlets 32, 90 of the downstream surfaces 54, 96 of the component 26, 67, 72. A fuel injection valve, characterized in that provided. 6. The fuel injection valve according to claim 1, wherein the coating is provided on the entire surface of the downstream surface 54, 96 of the component 26, 67, 72. 7. . 7. Fuel injection valve according to claim 6, characterized in that the coating extends in the outlet (32, 90) in addition to the coating of the surface (54, 96) of the component (26, 67, 72). 6. A fuel injection valve according to any one of claims 1, 4 or 5, wherein the fluorine-containing layer is applied by injection. 6. The fuel injection valve according to any one of claims 1, 4 or 5, wherein the fluorine-containing layer is applied by dipcoating. delete delete delete delete delete

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