DE10220931C1 - Injector for fuel injection - Google Patents

Abstract

The present invention relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine. The injector comprises an injector body (2), a nozzle needle (3) and a control device (13) to control a pressure in a control chamber (4) for actuating the nozzle needle (3). The injector (1) further comprises an inlet throttle (6) and an outlet throttle (7), which are in fluid communication with the control chamber (4). The inlet throttle (6) and the outlet throttle (7) are arranged in a throttle module (5) formed as a separate component and sealed by means of cutting edges.

Description

The present invention relates to an injector for one injection of fuel into a combustion chamber of an internal combustion engine Machine with the features of the preamble of claim 1.

Fuel injection injectors are for example for common Rail systems known in different configurations. A conventionally constructed injector comprises a nozzle needle, which indirectly via a control piston or directly with communicates with a control room that is pressurized is struck. If the same on the nozzle and on the control room There is pressure, so is the geometrically predetermined Ratio of the areas where the pressure ripened, one resulting force generated. For example, if the area on the nozzle is smaller than the area on the control piston a resulting force that the nozzle needle generates in its Presses the seat and closes the nozzle.

The control room is connected via a so-called inlet throttle an area of high pressure from a reservoir (rail) the one that is also led to the nozzle. about a so-called flow restrictor is also available to the control room a control valve in connection. Since the outlet throttle NEN larger flow cross section than the inlet throttle points, the pressure in the control room drops by opening the Ab control valve. This pressure drop in the control room the resulting force on the nozzle needle changes so that the nozzle needle lifts off its seat and fuel through the Spray hole bores in a combustion chamber of the internal combustion engine can flow out. In the previous injectors, the Control room and the inlet throttle or the outlet throttle each because introduced into an injector body. As a result, the Injector body is and is a relatively complicated structure  relatively complicated from a manufacturing point of view because there are a large number of operations on the injector body must be executed.

WO 00/06892 A2 describes a fuel injection valve for Internal combustion engines are known, in which one as a throttle plate trained throttle body between a valve body and an intermediate body or a nozzle body axially ver is tense. The throttle plate has a fuel channel on the ver via an inlet channel with a control chamber is bound, which in turn with a drain channel Servo valve is connected. The face of the throttle plate form a high pressure-resistant with the axially adjacent bodies Seal. With this fuel injection valve it is necessary agile, a very good sealing effect between the valve body and the throttle plate on the one hand and the throttle plate and to ensure the intermediate body on the other hand.

It is therefore an object of the present invention to To provide an injector for the injection of fuel, which can be used in particular in a common rail system is simple in construction and inexpensive is adjustable.

This task is carried out by an injector with the characteristics of Claim 1 solved. The subclaims show advantage adhesive developments of the invention.

The injector according to the invention is constructed such that a Inlet throttle and one outlet throttle in one as a separate one Component-designed throttle module are provided. Through the Arrangement of the two chokes in a separate component can Manufacturing advantages can be achieved because the Chokes, which gefer with a particularly high accuracy must be easily accessible in the separate component can be introduced. Then assembly of the throttle module in the injector.  

Another is also preferred in the separate throttle module Reset element, e.g. B. a coil spring to reset the Control device of the injector arranged. This allows the injector according to the invention be constructed more compact.

Another advantage is in the separate throttle module Recess formed which at least a portion of the Control room of the injector provides. This allows him to Injector according to the invention in the axial direction even more compact be formed. To prepare an even more compact injector set, the inlet throttle is preferably in the radial direction arranged to the injector axis. The is particularly preferred  Inlet throttle fuel under pressure via egg between the injector body and the separate throttle body dul arranged annular gap supplied.

To securely seal the annular gap between the injector gate body and the separate throttle module can be reached the annular gap is preferably sealed in the axial direction. Be the sealing is particularly preferably carried out by means of Cutting edges, which are plastic during assembly Experience deformation or a plastic deformation on the cause other component, so that a secure seal is made possible.

The throttle module in a stepped bore is particularly preferred tion of the injector body with at least two stages net. The annular gap is sealed axially direction at the steps of the stepped bore. With an Abdich tion by means of cutting edges, the cutting edges either in the throttle module or on the steps in the injector body be trained.

The invention based on a preferred Aus described in connection with the drawing ben.

The single figure shows a schematic sectional view a region of an injector with an inventive Throttle module.

As shown in Fig. 1, the injector 1 comprises an injector body 2 in which a throttle module 5 and a control module 13 are arranged. Furthermore, egg ne nozzle needle 3 is arranged in the injector body 2 and the In jektors out in the axial direction XX in the injector body. 2 The throttle module 5 is designed as a separate component. An inlet throttle 6 and an outlet throttle 7 are formed in the throttle module 5 . Further, at the end of the throttle module 5 directed towards the nozzle needle 3 , a cut-out U-shaped cutout 8 is formed. This recess 8 provides a control chamber 4 between the throttle module 5 and the nozzle needle 3 . The control module 13 comprises a valve 15 which can be actuated via a control unit, not shown, such as a magnetic element or a piezo actuator. The valve 15 closes or releases a valve seat 18 formed on the control module 13 . The valve 15 is reset by means of a return spring 14 designed as a spiral spring. Furthermore, two returns 16 are provided in the control module 13 , which provide a connection to a tank, not shown, of the vehicle.

As can further be seen from FIG. 1, the spring 14 is arranged in a recess formed in the throttle module 5 , so that a very compact design in the axial direction XX of the injector 1 is possible.

As can further be seen from FIG. 1, the inlet throttle 6 is fuel under pressure via a fuel feed line 19 and an annular gap 17 formed between the injector body 2 and the throttle module 5 .

Since the throttle module 5 is designed as a separate component, a seal must be formed between the throttle module 5 and the injector body 2 . As shown in Fig. 1, the throttle module 5 is arranged in a stepped bore of the injector body, which consists of a first stage 11 and a second stage 12 . In this exemplary embodiment, the annular gap 17 is sealed in the axial direction XX of the injector 1 . This seal is provided by a first cutting edge 9 and a second cutting edge 10 , which are formed on shoulders of the throttle module 5 , which correspond to the steps 11 , 12 of the stepped bores.

When the throttle module 5 is installed in the injector body 2 , the cutting edges 9 and 10 are plastically deformed at the steps 11 and 12 of the step bore. As a result, the surfaces of the two components 2 and 5 adapt ideally to one another, as a result of which a very good sealing effect is achieved. This sealing effect is tight even at very high pressures, such as occur in common rail injection systems. Furthermore, can be compensated for by the provision of the plastically deforming cutting edges 9 and 10 by the manufacturing be related length differences between the distances of the steps 11 , 12 of the stepped bore and / or the distances formed on the throttle selmodul 5 between the cutting edges 9 and 10 , This makes it possible for the manufacturing tolerances to be selected in a further area, so that the manufacture of the injector can be made cheaper. Furthermore, by providing the throttle module 5 as a separate individual component, the holes for the throttle 6 and the throttle 7 can be carried out quickly and easily with high accuracy. Likewise, the cutting edges 9 , 10 provided on the throttle module 5 can be produced very inexpensively, for example by turning.

The function of the injector 1 according to the invention is as follows. If fuel is to be injected, the valve 15 is actuated by an actuator (not shown) and moved in the direction of the nozzle needle 3 , so that the valve 15 lifts off from its valve seat 18 . This opens a connection between the control chamber 4 via the outlet throttle 7 and the open valve 15 to the return 16 . As a result, the pressure in the control chamber 4 drops, so that the nozzle needle 3 moves in the axial direction XX of the injector into the control chamber 4 . As a result, the nozzle needle 3 lifts off its seat, so that at least one nozzle is released and fuel is injected through the nozzle into a combustion chamber of an internal combustion engine. The injection takes place as long as the valve 15 remains in its open state. The valve 15 is opened against the spring force of the spring 14 .

When the injection is to be ended, the valve 15 is actuated again via the actuator, so that by resetting the spring 14 it returns to its starting position in which the valve seat 18 is closed. As a result, the connection between the control chamber 4 and the return line 16 is interrupted again, so that the original pressure can build up in the control chamber 4 , since fuel under pressure is supplied via the inlet throttle 6 . As a result, the nozzle needle 3 moves back into its starting position and closes the injector nozzle, so that the injection of fuel has ended.

During the actuation of the control valve 15 or the Düsenna del 3 , a steady, secure sealing of the annular gap 17 between the injector module 2 and the throttle module 5 at the stages 11 and 12 of the injector body 2 can be ensured. It should be noted that the cutting edges 9 , 10 are of course not only provided in the throttle module 5 , but that cutting edges can also be provided in the same way on the steps 11 , 12 of the injector body, which are plastically deformed when the throttle module 5 is installed and produce a seal between the injector body 2 and the throttle module 5 .

The present invention thus relates to an injector for injecting fuel into a combustion chamber of an internal combustion engine. The injector comprises an injector body 2 , a nozzle needle 3 and a control device 13 in order to control a pressure in a control chamber 4 for actuating the nozzle needle 3 . Furthermore, the injector 1 includes an inlet throttle 6 and an outlet throttle 7 , which are in fluid communication with the control chamber 4 . The inlet throttle 6 and from the throttle 7 are arranged in a ge formed as a separate component throttle module 5 .

The previous description of the embodiment according to the present invention is for illustrative purposes only and not for the purpose of limiting the invention. In the frame Various changes and modifications are made to the invention tion possible without the scope of the invention and its Ä to leave equivalents.

Claims (4)

1. Injector for injecting fuel into a combustion chamber of an internal combustion engine, comprising an injector body ( 2 ), a nozzle needle ( 3 ), a control device ( 15 ) to a pressure in a control chamber ( 4 ) for actuating the nozzle needle ( 3 to control), an inlet throttle (6) and an outlet throttle (7), which are both connected to the control chamber (4) in fluid communication, wherein the at run choke (6) and the outlet throttle (7) in a space formed as a separate component porting module (5 ) are arranged, wherein an annular gap ( 17 ) is formed between the injector body ( 2 ) and the throttle module ( 5 ), via which fuel is supplied to the inlet throttle ( 6 ), the annular gap ( 17 ) in the axial direction (XX) of the In is sealed, the throttle module ( 5 ) being arranged in a stepped bore with at least two steps ( 11 , 12 ) of the injector body ( 2 ) and the sealing of the annular gap ( 17 ) in the axial direction on the steps ( 11 , 12 ) of the stepped bore, characterized in that the sealing takes place by means of cutting edges ( 9 , 10 ). 2. Injector according to claim 1, characterized in that in the throttle module ( 5 ) a reset element ( 14 ) for resetting the control device ( 15 ) is arranged. 3. Injector according to one of the preceding claims, characterized in that a recess ( 8 ) is formed in the throttle module ( 5 ), which provides at least a partial area of the control chamber ( 4 ). 4. Injector according to one of the preceding claims, characterized in that the inlet throttle ( 6 ) is arranged in the radial direction of the injector.