DE19719364A1 - High-rigidity common rail piezo-injector - Google Patents

Abstract

The piezo-injector has an annular piezo-stack which can be mechanically activated by the adjusting cylinder (15), taking up the jet rod (3) with jet-rod boring (11) at the same time. By means of the threaded components, the conical jet seat (2) is closed up to the necessary extent against the congruent end of the jet rod. The jet rod is screwed through the internal thread (14) and can be locked by a counter-thread shell (18). A sealing ring (4) is provided. The oil leakage channel (27) comes out to the annular channel (29).

Description

The invention relates to a fuel injection device in the preamble of claim 1 specified type.

Fuel injectors for internal combustion engines are widely used experienced and manufactured in diverse technologies.

Injectors of the type mentioned work with piezoelectric, magneto strictive or electrostrictive actuators as drive elements that are attached to a piston or a mem act bran, so that the required partial or total amount of fuel can be hosed off.

Based on this prior art, the invention is based on the object Particularly suitable for the common rail operation of gasoline, small-sized, wearable me device with good dynamic properties with sufficient needle stroke, high actuator, Nozzle needle and housing stiffness, which can be precisely controlled even at high operating frequencies and reproducible injection of partial fuel quantities for internal combustion engines using a tax body of the type mentioned in the preamble of claim 1.

This object is achieved by the characterizing features of claim 1. Advantageous developments of the invention are due to the dependent on this claim sayings marked.

In the following the invention is based on a preferred embodiment in conjunction described with a simplified sectional drawing. It shows:

Fig. 1. shows the schematic structure of the fuel injector, in which the inherently stable Ge housing ( 8 ) is designed as a tubular spring or bellows and the drive element ( 7 ) is preferably worked as a ring piezo stack and with the nozzle rod ( 3 ) the nozzle rod bore ( 11 ) is penetrated. The drive element ( 7 ) is pretensioned by the adjusting cylinder ( 15 ) with the spherical disc ( 23 ). Then the external thread ( 24 ) of the nozzle rod ( 3 ) is turned into the internal thread ( 14 ) of the adjusting cylinder ( 15 ) and pressed with the necessary sealing pressure onto the congruent conical nozzle seat ( 2 ). To secure the nozzle rod ( 3 ), the counter-threaded sleeve ( 18 ) is turned into the internal thread ( 14 ). The leakage oil channel ( 27 ) takes up the leakage oil accumulating on the sealing ring ( 4 ), which is sucked off by the negative pressure in the active injector into the ring channel ( 29 ) and the bore ( 31 ), in order to supply it to the combustion chamber. If necessary, the annular gap ( 9 ) can be sprayed with elastic silicones. In order to achieve even greater mechanical protection, the housing ( 8 ) can be surrounded by the protective casing ( 25 ) in which the housing ( 8 ) can run freely or smoothly.

Reference list

1

Spray hole

2nd

Nozzle seat

3rd

Nozzle rod

4th

Sealing ring

5

thread

6

Temperature ring compensation element

7

Drive element

8th

casing

9

Annular gap

10th

Annular gap

11

Nozzle rod bore

12th

inner thread

13

External thread

14

inner thread

15

Adjustment cylinder

16

Lock nut

17th

Connecting piece

18th

Counter thread sleeve

19th

Hexagon socket

20th

External thread

21

drilling

22

Hexagon socket

23

Spherical disc

24th

External thread

25th

Protective casing

26

inner thread

27

Leakage oil channel

28

Nozzle cylinder

29

Ring channel

30th

Nozzle base

31

drilling

Claims (7)

1. Fuel injection device for spraying off fuel in a rotati onsymmetrischen housing made of metal, characterized in that the nozzle rod ( 3 ) with the nozzle rod bore ( 11 ) after exposure to the necessary bias by the spring action of the inherently stable housing ( 8 ) on the drive element ( 7 ) through the adjusting cylinder ( 15 ) and the spherical washer ( 23 ), so screwed through the internal thread ( 14 ) and secured with the counter-threaded sleeve ( 18 ), that the conical nozzle seat ( 2 ) with the required sealing pressure of the congruent nozzle seat side End of the nozzle rod ( 3 ) who can provide the sliding bearing in the nozzle cylinder ( 28 ) which is provided with the sealing ring ( 4 ), the leakage oil channel ( 27 ) opening into the ring channel ( 29 ) and the nozzle rod ( 3 ) the drilling tion ( 31 ) is penetrated and ends sealingly on the nozzle seat ( 2 ), whereby in each case by the n negative pressure during the spraying process, the leak oil is extracted. 2. Fuel injection device according to claim 1, characterized in that the drive element ( 7 ) is constructed as a perforated disk piezo ring stack or homogeneous piezo tube. 3. Fuel injection device according to claim 1 and 2, characterized in that the housing ( 8 ) is designed as a tubular spring or bellows. 4. Fuel injection device according to one of claims 1 to 3, characterized in that the annular gap ( 9 ) can be sprayed with elastic plastic and that the housing ( 8 ) with the protective jacket housing ( 25 ) may or may not, which with the thread ( 5 ) on the housing ( 8 ) can be fixed. 5. Fuel injection device according to one of claims 1 to 4, characterized in that more than one spray hole ( 1 ) is embedded in the nozzle base ( 30 ). 6. Fuel injection device according to one of claims 1 to 5, characterized in that the nozzle rod ( 3 ) can have different diameters for the same component. 7. Fuel injection device according to one of claims 1 to 6, characterized in that the combustion chamber distal end of the protective casing ( 25 ) receives the fuel line connection in a positive or non-positive connection in a homogeneous extension, the supply line to the connecting piece ( 17 ) being elastically designed is.