JPS61244867A - Fuel injection valve for diesel-engine - 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 The present invention provides a diesel engine fuel injection valve having a casing and a nozzle body fixed within the casing, the nozzle body having a nozzle opening leading to a combustion chamber and a valve needle cooperating with the nozzle opening. A working valve seat is arranged, and the housing has a fuel chamber which surrounds the valve needle in an annular manner.

In the case of the known fuel injection valve of the above type, for example according to Swiss Patent No. 614,495, the valve needle is guided so as to be axially slidable in the casing. . The nozzle body also extends from the valve seat to the combustion air conditioning wall of the annular fuel chamber that is open toward the valve needle, and the nozzle body extends axially from the fuel chamber to the valve seat with a tapered valve needle end. It forms an annular cap extending towards. During operation,
Particularly high loads are placed on the cooperating parts of the injection valve under relatively high fuel pressures, for example over 1200 bar. In the case of this known injection valve, the entire housing is made of relatively expensive material. This material is particularly defined by the bearing properties required for guiding the valve needle.

The underlying issue of this review is to create a fuel injection valve that is simpler and cheaper than the conventional type, especially with improved fuel injection valves.
The purpose of this is to maintain the conventional structure to a sufficient extent and to provide it in a form that requires as little manufacturing and material costs as possible.

1.Means to solve the problem This problem was solved by the present invention as follows.

That is, the nozzle body is provided with a sleeve part which extends from the valve seat over substantially the entire length of the casing, measured in the axial direction of the valve needle, and which is fixedly connected to the casing, and furthermore, this sleeve part extends over approximately the entire length of the casing, measured in the axial direction of the valve needle. It helps guide and also seals and confines the fuel chamber inwardly. In addition, this sleeve part is provided with a lateral passage for fuel in the area of the fuel chamber.

The fuel injection valve type according to the invention replaces a stationary valve part with a highly loaded guide part having a total guiding area for the valve needle and a highly loaded guide part which is completely separated from the valve needle and receives a correspondingly lower load. It becomes possible to functionally divide the holding part into a holding part. Therefore, the holding portion can be manufactured using a simpler material and at a lower processing cost than before.

In order to make the volume of the nozzle body interior formed between the valve seat and the end of the nozzle body on the combustion chamber side as small as possible, which is particularly advantageous for optimal fuel utilization, it is necessary to It is advantageous if the nozzle opening is arranged in the longitudinal region of the nozzle body surrounded by the housing edge area and is arranged in the immediate vicinity of the valve seat.

An exemplary embodiment of the invention will now be explained with reference to the drawings: The illustrated fuel injection valve has a housing 1 with a central bore 2 in which a nozzle body 3 is arranged. The nozzle body 3 has a sleeve portion 4 extending over the entire axial length of the casing 1 . At its upper end in the figure, this sleeve part 4 has a collar 5, which rests on the correspondingly enlarged step of the bore 2.

The nozzle body 3 is shrink-fitted into the casing 1 over its entire length, and its lower end 6 is connected to the diesel engine (
(not shown) has entered the combustion chamber. This lower end 6 has a multi-nozzle opening lower opening leading to the combustion chamber and a conical valve dust 8 for the valve needle 10 . The valve needle 10 is
It is guided in the hole of the sleeve portion 4 so as to be slidable in the axial direction while being sealed. The sleeve part 4 may optionally be shrink-fitted into the casing 1 only over part or parts of its entire length.

The nozzle body 3 is surrounded by an annular fuel chamber 11 configured in the housing 1 and an annular cooling channel 12 correspondingly formed near the lower end of the housing 1 . The fuel chamber 11 is connected to a fuel injection pump (not shown) via a fuel passage 13 and a fuel conduit (not shown). The cooling passage 12 is connected via cooling holes 14 to a liquid refrigerant supply system (not shown). Refrigerant is supplied to the cooling passage 12 through cooling holes 14 and is discharged through additional cooling holes (not shown) of similar construction.

In the illustrated embodiment, the additional cooling holes are formed in the diametrical direction of the cooling holes 14, and the fuel passage 13 is arranged offset from these cooling holes by 90°.

The sleeve part 4 of the nozzle body 3 is arranged in the area of the fuel chamber 14,
It has a passage opening 15 in the radial direction. These passage holes 1
5, the fuel chamber 14 is brought into communication with an annular gap 16 formed between the tapered part of the valve 21 and the inner wall of the nozzle body 3. This annular gap 16 is formed at its upper end by the sealing gap formed between the sleeve part 4 and the valve needle 1o, and at its lower end on the combustion chamber side with a corresponding seat surface of the valve needle 10. They are each limited by a working valve seat 8.

The upper part of the housing 1 is fixed in the engine in a manner known per se that does not require further explanation. The valve needle 10 is then pressed against the valve seat 8 by a spring (not shown). During operation, the fuel pressure generated by the injection pump and acting in the fuel chamber 11 and in the annular gap 16 lifts the valve needle 10 in each case and fuel is injected into the combustion chamber via the nozzle opening lower. Ru.

The valve seat 8 is formed in a longitudinal portion of the nozzle body 3, which is partially surrounded by the weave area of the casing 1 on the combustion chamber side and partially protrudes into the combustion chamber area. As can be seen from the illustrated embodiment, in this way the distance between the valve seat 8 and the nozzle opening lower, measured in the axial direction of the nozzle body 3, can be kept particularly small. Correspondingly, the space 17 surrounding the tip of the valve needle 10 can have a particularly small volume. The amount of fuel that remains in this space 17 and flows uncontrolled into the combustion chamber each time the injection valve is closed is therefore correspondingly small, so that optimum fuel utilization is achieved.

The fuel injection valve constructed according to the present invention is characterized by a particularly simple construction. This is because the fit of the nozzle body 3 in the casing 1 is possibly enlarged in the area of the collar 5 and requires essentially only one continuous hole 2 in other parts.

Since guide surfaces and sealing surfaces that cooperate with the movable valve needle 10 and are therefore correspondingly loaded are formed on the nozzle body 3, the housing 1 is made of a material that is correspondingly cheaper than in the conventional version. Can be used.

According to a variant of the invention, the nozzle body 3 and the casing 1
Instead of a shrink fit between the parts, other types of connections can be used. For example, suitable soldering, bonding or adhesive bonding is possible, which is suitable for the temperature conditions prevailing in the case of the illustrated type of injection valve. In the case where the nozzle body 3 and the casing 1 are adhesively bonded, the nozzle body 3 is connected to the casing 1.
It can be manufactured completely independently from the valve body 3 and also allows mutual adaptation of the nozzle body 3 and the valve needle 10 which is spliced into the nozzle rest 3. This makes it possible, for example, to stock these movable cooperating parts as complete sets that can be assembled respectively. Accordingly, the damaged nozzle body 3 can be removed from the casing 1 at a slight assembly cost in each case, and after the contact surface has been treated accordingly, a new nozzle body can be installed together with the valve needle 10. 3 can be exchanged.

[Brief explanation of drawings]

The drawing is a sectional view of a fuel injection valve according to the invention, with the cut plane in the left half of the drawing being offset by 90° with respect to the cut plane in the right half. In the figure, 1... Casing 3... Nozzle body 4... Sleeve portion 5... Sleeve portion collar 7... Nozzle opening 8 ... Valve seat 10 ... Valve needle 11 ... Fuel chamber 12 ... Cooling passage 13 ... Fuel passage 15 ...・Radial passage hole 16...Annular gap

Claims (4)

[Claims] (1) a diesel engine fuel injection valve having a casing (1) and a nozzle body (3) fixed in the casing, also in the nozzle body (3) a nozzle opening (7) leading into a combustion chamber; In those types in which the valve needle (10) is arranged with a cooperating valve seat (8), it extends from the valve seat (8) over substantially the entire length of the casing measured in the axial direction of the valve needle (10). and the casing (
The nozzle body (3) is provided with a sleeve part (4) which is fixedly connected to the valve needle (10) and which serves to guide the valve needle (10) and which also serves to guide the fuel chamber (10).
11) is sealed and restricted inwardly, and further,
A fuel injection valve for a diesel engine, characterized in that this sleeve part (4) is formed with a lateral fuel passage opening (15) in the area of the fuel chamber (11). (2) Claim 1, characterized in that the sleeve portion (4) is joined to the casing (1) by a shrink fit.
Fuel injection valve as described in section. (3) The fuel injection valve according to claim 1, characterized in that the sleeve portion (4) is joined to the casing (1) by adhesive. (4) A valve seat (8) is formed in the longitudinal section of the nozzle body (3) surrounded by the combustion chamber side edge area of the casing (1), and also the nozzle opening (7) 4. Fuel injection valve according to claim 1, characterized in that it is arranged in the immediate vicinity of the seat (8).