JPS62139970A - Injection valve - 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 Industrial Application The present invention is an injection valve for a fuel injection device for an internal combustion engine, which comprises a valve seat and a nozzle needle, the nozzle needle cooperating with the valve seat. a sealing section disposed upstream and guiding the nozzle needle in the guide hole with its circumferential surface; The present invention is of the type in which at least one metering opening facing the other side is arranged, and an intermediate volume is closed between the guide section, the sealing section, the guide bore and the valve seat.

In order to avoid the occurrence of deposits on the suction y side in the conventional technical t@ cross section, rtx injection valves are already known in which a stiff cross section is arranged above the sealing section. West Germany pin application released! No. 3,418,761 discloses a device in which the metering of the needle is controlled by means of a hole in the guide section that guides the needle. In such valves, the filler with the metering hole and located between the ratio guide section and the sealing section of the valve is usually designed to have a minimum volume. This should largely avoid the respective currents at the start of the fuel flow at the moment of valve opening, i.e. vI4
The kinetic energy released by the pressure drop in the volume section must be used directly for regulating the jet flow in the area of the sealing section and the injection opening, without flow losses due to excessively large dead volumes.

However, a disadvantage of such injection valves is that problems arise due to fuel starvation, especially during hot starts of internal combustion engines that suffer from such injection valves. The cause is the valve tip.
The effect of this is that fuel vapor bubbles are waved within the area of the injection opening. This injection of fuel mixed with vapor bubbles causes an error in the fuel/air ratio, which in turn causes problems when starting the internal combustion engine.

OBJECTS OF THE INVENTION An object of the present invention is to solve the drawbacks of the above-mentioned known examples.

Means for Solving the Problems According to the present invention, the above problem can be solved by determining the size of the intermediate volume v2 (
1 m3) is the static throughflow t Qstat, (an” 7
The solution is to dimension it so that it is selected only slightly according to the equation Vz ''-Qstat-F.

Advantages of the invention The advantages of the invention are achieved by advantageously selecting the size of the intermediate volume placed between the fitting section and the valve seat.
Fuel injection under various conditions during hot starting can be improved by appropriate use of fuel evaporation. Example 1 Fuel for a mixture compression external ignition internal combustion engine shown as an example in FIG. 1! The fuel injection valve of the Jt injection device has a valve housing 1 made of ferromagnetic material, in which a magnetic coil 3 is arranged on a coil holder 2 . This magnetic field 3 is supplied with power via a plug connection 4, which is embedded in a plastic ring 5 which partially surrounds the valve housing 1.

The coil holder 2 of the magnetic coil 3 is arranged in the coil holder 6 of the valve casing 1 on a connecting piece 7 for supplying fuel, for example gasoline, which connecting piece 1 is partially connected to the valve. It has entered casing 1. The valve housing 1 partially surrounds the nozzle body 9 on the side opposite the connecting tube piece 7 .

Between the shoulder surface 11 of the connecting spine 7 and the plate 12, there is a stop δ having a predetermined thickness and resting on the inner shoulder 13 of the valve casing 1 for precise adjustment of the valve. , fuel ux
A cylindrical 5Jpjh element 14 of the injection valve is arranged. This magnetic element is made of a magnetic material that is resistant to 14 scratches. A compression spring 16 that acts on the movable element 14 is disposed between the movable element 14 and a push-in 'I#is' which is fixed to the connecting tube piece 7 by a slight wrinkling process of the Sakura tube piece. . On the other side, a nozzle needle 1γ is disposed within this mover 14.
is fixed, so that the needle 11 is inserted into the armature bore 19 of the armature 14 with the ring groove end 18 and the armature material is radially inward. It is held by being pushed into the ring groove of the Herring groove end 18.

The nozzle needle 11 is fitted with radial play between the through opening 20 in the plate 12 and the guide hole 21 in the nozzle body 9.
and the nozzle body 9 using the needle bottle 22.
It protrudes from the 'Jt radiation aperture 23 of. A conical valve seat surface 24 is provided between the guide hole 21 and the injection opening 23 of the nozzle body 9.
is formed. Due to manufacturing technology reasons, the nozzle body 9
A groove 26 (see also FIG. 2) is formed as an undercut between the inner guide hole 21 and the conical valve seat surface 24, and the diameter of this groove 28 is equal to the diameter of the guide hole 21. The diameter is also large.

The nozzle needle 1γ has two guide sections 33, 34, each of which guides the nozzle needle 17 in the guide bore 21 and has an axial X passage for the fuel hole, so that the guide section 34 The guide section 33 located upstream of is designed, for example, as a square element. A metering opening 27 is machined in the guide section 34 located on the downstream side (2), through which the fuel flows from the upstream side of the guide section 34 to the bottom i of the guide section 34 when the pressure decreases.
Flows to the k side. In addition, as shown in □□□, each metering opening 27 extends parallel to the guide hole 21 or is inclined to the guide hole 21, and in this case, the metering opening 27 additionally has a function of controlling whether the fuel is v? It is also possible to form the fuel so that it flows out from the opening 21 in a swirling manner, thereby making it possible to significantly improve the fuel flow. Furthermore, this metering opening 27 can also be formed as a hole (as shown) or as a groove or slit machined into the circumferential surface of the guide section 34. Seen in the downstream direction, behind the guide section 34 the nozzle needle 17 is tapered in steps, ie a first conical section 28 is followed by a cylindrical section 29, which 29 is followed by a conical section 30. This conical section 30 cooperates with the conical valve seat rkJ24 of the nozzle body 9 to open and close the valve. A second conical section 31, which tapers in the direction towards the needle bin 22, is arranged between the conical sealing section 30 and the needle bottle 22.

The lengths of the nozzle needle 11 and the armature 14 are such that, starting from the sealing section 30, the armature 14 freely forms a working gap A with respect to the end face 11 of the connecting tube 7 in the de-energized state of the magnetic coil 3. Dimensionally designed.

A notch 31 is formed between the through opening 20 and the circumferential surface of the abutting plate 12, and the inner diameter of this notch 37 matches the ring groove end 18 of the nozzle needle 11 and the abutting shoulder 39. The diameter in the corresponding range 38 between them is also larger. In the excited state of the magnetic coil 3, the movable element 14 is compressed by the compression spring 16 in the opening direction of the nozzle needle 1γ.
The abutting shoulder 39 still contacts the abutting plate 12.

The magnetic flux is guided through the jacket part of the casing 1 via a flux guide crotch 40 to the cylindrical armature 14, and from there to the valve casing via a connecting piece 7 with a guide flange 41 and serving as a core. There is a guide to return to. The eel bundle guide step 40 of the valve casing 1 is formed radially inward and surrounding the movable element 14.
.

The arrangement of the adjustment opening 21 upstream of the sealing section 30 prevents particles from the atmosphere in the intake manifold from depositing in the adjustment opening 21. In contrast, if the needle bottle 22 does not distribute oil into the relatively large gap between the needle bottle 22 and the wall of the injection opening 23 or if the needle bottle 22 does not distribute oil, it will not accumulate inside the injection opening 23. It has only a small effect on the phased fuel performance.

Very generally, the guide section 1ffl is formed by the second guide section 34, the first conical section 28, the cylindrical section 29 of the nozzle needle 17, the guide hole 21, the ring 26 and the square illuminated surface 24 of the nozzle body 9. volume, t”tigls intermediate volume 43
It has been a long tradition to make the size as small as possible. This reduces the flow state between the opening 27 and the seal section 30 as much as possible, or prevents the injection opening 23 from deteriorating as much as possible the flow formed at the opening 27 (close to a vortex). This is to help them reach this goal. -However, when starting an internal combustion engine with the f4 top in which the injector valve is closed, fuel within the range of the injection opening 23 is caused to open due to frequent heating of the nozzle body 9 or nozzle needle 170 after the internal combustion engine is stopped. Furthermore, if the load is reduced and the fuel is partially evaporated, it becomes difficult to start it. This results in an undesirable reduction in the air/fuel ratio during startup.

In this state, the internal combustion engine cannot be started until the nozzle needle 11 and nozzle body 9 are cooled down again to a safe sensitivity of 1.
i] Become Noh.

On the other hand, if the shape of the intermediate volume 43 is too thick, the above-mentioned curved shape or rounded shape will occur.

It is therefore an object of the invention to design the intermediate volume 43 in such a way that the above-mentioned disadvantages do not arise. Experiments with the injector according to the invention have revealed that, with a suitable selection of the size of the intermediate volume M43, the hot starting characteristics can be improved by utilizing rather the evaporation of the fuel in the intermediate volume 43. ing. I will explain this point below.

While the injection valve is closed, the pressure in the intermediate volume 43 and the system pressure (above the second id section 34) are the same.

When the magnetic coil 3 is energized, the seal section 30 closes to the valve seat surface 2.
4, the pressure in the intermediate volume 43 is rapidly reduced at the intake port pressure point via the opening cross-section which is lifted up from 4 and released in this case, and the pressure drop at the metering opening 27 and the injection opening 23 is subsequently reduced. The pressure rises to the ratio specified by the ratio. Vapor bubbles are formed within the intermediate volume due to the sudden unloading of fuel within the intermediate volume during the opening phase.

As a result, the pressure in the intermediate volume 43 rises above the constant voltage value within a few hours, so that even during this injection phase sufficient fuel (in liquid or vapor form) is injected for starting the internal combustion engine. be done. By properly designing the size of the intermediate volume 43, the size of the sea bream opening 270, and the size of the injection opening 23, a certain enrichment characteristic can be formed even in a certain accuracy range and limit state at the tip of the injection valve. It will be done. Only when the blackness at the tip of the injector reaches such a height that all the fuel in the intermediate volume 43 evaporates does starvation occur during start-up. However, the size Q:iM of this intermediate content horizontal 43 is expressed by the following formula.

Vz = Qstat F Vz: Size of intermediate volume (3) Qstat: Static X-filling area at injection opening 23 (c
Ir13/min] F: Correction factor < 141 x s/100 an') min C (D) The minimum static X-accent change is about 130 x 3/min.

According to the invention, a normal cold start characteristic of the injector is demonstrated if the correction factor F lies between 2 and 7 (1113/100 ci!) minutes.

The pressure distribution, ie the relationship between the pressure drop at the needle opening 21 and the residual pressure drop at the injection opening 23, is then expressed as 9
= 1 (corresponding to a pressure drop of 90% at the metering opening and a pressure drop of 1% at the injection opening) and 1:1 (! 50% pressure drop at the J4 opening and a pressure drop of 5% at the injection opening)
0%).

[Brief explanation of drawings]

The drawings show an embodiment 11 of the present invention, and FIG. 1 is a vertical view of an injection valve according to the present invention, and FIG. 2 is an enlarged partial view of FIG. 1. 1...Valve casing, double coil holder, 3...Magnetic Koino V, 4...-insertion lady@Miyako, 5...Plastic ring, 6...Coil plan, 7...Connection snowflake, 9・
... Nozzle body, 11 ... End face, 12 ... Attachment is plate, 13 ... Inner shoulder, 14 ... Mover, 1
5... Matchmaker v, 18... Pressure spring, 11... Nozzle needle, 18... Ring fermentation end, 19... Mover hole, 2 (J... X opening, 21 ... Guide hole, 22
... Needle bin, 23... Injection opening, 24...
Valve seat surface, 2Fi...groove, 27...metering opening, 29.
...Cylindrical section, 30...Cylindrical seal section, 31.
・Conical section, 33.34...Guide section, 31...
- Notch, 38... Range, 39... Attachment is shoulder, 4Ll... Fμ bundle tea inner throw part, 41... Guide flange, 43... Middle 14. li Tani Maki. 17... Nozzle needle 21... Guide hole 24... Valve seat surface 34... Guide section 43... Intermediate volume

Claims (2)

[Claims] 1. An injection valve for a fuel injection device of an internal combustion engine, comprising a valve seat and a nozzle needle, the nozzle needle being arranged upstream and having a circumferential surface and a sealing section cooperating with the valve seat. a guide section for guiding the nozzle needle in the guide bore, in which at least one metering opening is arranged extending from the upstream side towards the downstream side of the guide section; In the type in which an intermediate volume is closed between the guide section, the seal section, the guide hole and the valve seat, the size of the intermediate volume (43) is V_
2 (mm^3) is the static flow rate Qstat (cm^3/
minutes), according to the formula V_2=Qstat・F,
Moreover, the correction coefficient F is 2 to 7 (mm^3/100c
An injection valve characterized in that the dimensions are designed to be set to a value of m^3/min). 2. 2. Injection valve according to claim 1, wherein the pressure drop at the metering opening (27) has a value between 50 and 90% of the total pressure drop.