WO2016059079A1

WO2016059079A1 - Injection valve for injecting fluid into a combustion chamber of an internal combustion engine

Info

Publication number: WO2016059079A1
Application number: PCT/EP2015/073722
Authority: WO
Inventors: Wendelin KLÜGL
Original assignee: Continental Automotive Gmbh
Priority date: 2014-10-15
Filing date: 2015-10-13
Publication date: 2016-04-21
Also published as: DE102014220841A1

Abstract

The invention relates to an injection valve (10) for injecting fluid into a combustion chamber of an internal combustion engine. The injection valve (10) has an injector body (20), which has a fluid feed (30) for feeding pressurized fuel fluid and a fluid outlet (210). The injection valve also has a nozzle body (40), which has a cavity (50), which is hydraulically coupled to the fluid feed (30) and in which a nozzle needle (60) is arranged in an axially movable manner, wherein the nozzle needle (60) interrupts a fluid flow through an injection opening (80) of the nozzle body (40) in a closing position and otherwise allows said fluid flow. The injection valve (10) also has a control chamber (150), which is hydraulically coupled to the fluid feed (30) and to the nozzle needle (60). Furthermore, a control valve (170) having a valve body (200) and having a valve chamber (160) is provided, which valve chamber is hydraulically coupled to a control chamber (150), wherein the valve chamber (160) can be hydraulically coupled to the fluid outlet (210) depending on a closing position of the valve body (200), and an actuator (220) is provided, which can be coupled to the valve body (200) in order to actuate the control valve (170). The injection valve (10) is distinguished in that the valve chamber (160) additionally can be hydraulically coupled to the cavity (50) in the nozzle body (40).

Description

description

Injection valve for injecting fluid into a combustion chamber of an internal combustion engine

The invention relates to an injection valve for injecting fluid into a combustion chamber of an internal combustion engine.

Due to increasingly stringent legislation regarding permissible pollutant emissions of internal combustion engines, which are arranged in motor vehicles, it is necessary to take various measures that contribute to lowering the pollutant emission. Today's common rail systems must meet the requirements for multiple injection with small tolerances and small injection intervals of up to -S 150 ys. These requirements are not met by today's piezo injectors at Dwell, Pilot2Pilot volumes and tolerances, and even at full load volume tolerances. This results in the engine considerable disadvantages in terms of exhaust emissions (HC and CO), the specific fuel consumption and also in terms of Ver ^¬ combustion noise. The motor values can go ^¬ clearly Abgaserfüllbarkeit EU6, combustion noise (comfort) and most economical fuel consumption - depending on the vehicle and vehicle mass - not at all or at least relatively poorly fulfilled.

It is therefore the object of the present invention to eliminate or at least significantly reduce the above-mentioned disadvantages and problems.

According to the invention, an injection valve for injecting fluid into a combustion chamber of an internal combustion engine is disclosed for this purpose. The injection valve has an injector body with a fluid inlet for supplying pressurized fuel fluid and a fluid outlet. Furthermore, the injection valve has a nozzle body with a hydraulically coupled to the fluid inlet recess, in which a Dü- sennadel is arranged axially movable. The nozzle needle un ^¬ terbindet in a closed position, a fluid flow inlet injection openings of the nozzle body and passes this otherwise free. The injector further has a control chamber which is hydraulically ge ^¬ coupled with the fluid inlet, and with the nozzle needle. Furthermore, the injection valve has a control valve with a valve body and a valve chamber. The valve chamber is hydraulically coupled to the control room. Depending on a closed position of the valve body, the valve chamber can be hydraulically coupled to the fluid outlet. Furthermore, an actuator is provided, which can be coupled to the valve body for actuating the control valve. Moreover, the valve space is additionally hydraulically coupled with the recess in the nozzle body. Typically, the control room is via a throttle with the

Valve chamber hydraulically coupled. This contributes to the fact that when opening or closing the control valve usually in the control room a much higher pressure prevails, as in the valve chamber. The additional coupling of the valve chamber with the recess in the nozzle body, which is constantly acted upon by highly pressurized fluid, the injector function can be improved between and during the various injection stages. According to one embodiment of the invention, the hydraulic coupling of the valve chamber with the recess in the nozzle body is suppressed when energized (actuated) actuator. Consequently, the valve space during the injections is not in fluid communication with the recess in the nozzle body, so that it can not lead to an unintentional pressure loss / pressure drop there.

According to a further embodiment, the hydraulic coupling between the valve chamber and the recess of the nozzle body is formed as a bore, which opens into the valve chamber in the region of the valve body. Such a bore can be relatively easy to introduce manufacturing technology in the throttle plate. According to a further embodiment, the valve body closes the bore when actuated actuator and thus prevents the hydraulic coupling between the valve chamber and the recess. By means of the closable bore through the valve body a minimum leakage is ensured.

According to a further embodiment of the invention, the bore is formed as a bypass throttle. This allows the flow of fluid through the bore to be regulated and calculated.

According to a further embodiment of the invention, the fluid inlet to the recess of the nozzle body is formed with a diaphragm. By means of the diaphragm, a pressure difference increase is generated in the fluid inlet.

According to a further embodiment, the diaphragm has a diameter of at least 0.6 mm. The increase in the usual aperture diameter helps to reduce the pressure loss in the recess in the nozzle body (nozzle chamber).

According to a further embodiment, an inlet throttle is provided between the fluid inlet and the control chamber.

According to a further embodiment of the invention, a spring element is provided, which exerts a force on the valve body in the closing direction of the control valve. In the spring ^¬ element is preferably a compression spring. The spring element contributes to a safe closure of the control valve. In particular, the spring element ensures that the control valve is securely closed even with a non-pressurized injection valve.

Further advantages and functions are described in the following detailed description of an embodiment with the aid of the appended figures.

In the figures show: Figure 1 is a schematic sectional view of an injection ^¬ valve and

FIG. 2 shows an enlarged sectional view of the injection valve from FIG. 1.

1 shows a schematic sectional view of an injection valve 10. The injection valve 10 comprises an in ^¬ jektorkörper 20, in which is formed a fluid inlet 30th The fluid inlet 30 is hydraulically coupled to a high-pressure fuel storage, such as a so-called common rail, and is thus supplied with a pressurized fuel. For example, the pressure is up to 2500 bar or higher. The term "fluid" can comprise a fuel or fuel, for example a diesel ^¬ or gasoline fuel. However, the term may also include other substances, for example organic compounds such as urea. The injection valve 10 has a nozzle body 40 in which a In the recess 50, a nozzle needle 60 is disposed axially movable with respect to a longitudinal axis of the nozzle needle 60. The nozzle needle 60 is seated in a closed position near a tip of the nozzle body 40 on an associated nozzle needle seat 70 and prevents fluid flow through one If the nozzle needle 60 is released from the nozzle needle seat 70, a fluid flow is released a combustion chamber seal 110 v esigned.

The recess 50 and the nozzle needle 60 are hydraulically coupled via an aperture 120 to the fluid inlet 30. The diaphragm 120 is inserted in a throttle plate 130.

The injection valve 10 furthermore has a control chamber 150 which is hydraulically connected via an inlet throttle 140 in the throttle valve. Seiplatte 130 is coupled to the fluid inlet 30. Of the

Control chamber 150 is also hydraulically coupled to the nozzle needle 60. The control chamber 150 is also hydraulically coupled to a valve chamber 160 of a control valve 170 via an outlet throttle 180 in the throttle plate 130. The control valve 170 is disposed in a valve plate 190 and is referred to as a servo valve. The control valve 170 has a valve body 200, which is arranged axially movably in the valve space 160. In a closed position of the control valve 170 of the valve body 200 is seated on an associated valve seat and prevents a flow of fluid from the valve chamber 160 to a fluid outlet 210. The fluid flow 210 is hydraulically coupled to a low ^¬ pressure range, such as a fuel tank.

The injection valve 10 has an actuator 220, which is designed as a piezoelectric actuator. Alternatively, other materials, such as a magnetostrictive material, may be used for the actuator 220. The actuator 220 is integrated into the injector body 20 in an invar sleeve and has an actuator head plate 230 and an actuator bottom plate 240. The actuator 220 is mechanically coupled to the injector body 20 via the actuator head plate 230 and the invar sleeve. The actuator 220 can be coupled to the control valve 170, in particular to the valve body 200, for actuation via the actuator bottom plate 240.

The actuator 220 is surrounded by a tube spring 250, which biases this. A diaphragm under the actuator bottom plate 240 seals the actuator 220 from the fluid.

At the beginning of an injection process, the injection valve 10 is closed. Via the fluid inlet 30, the recess 50, the control chamber 150 and the valve chamber 160 are completely filled with fluid under high pressure. At the same time, a fluid connection formed in the throttle plate 130, which may be formed, for example, as a bypass throttle, is provided. This fluid connection ^¬ 260 also couples the recess 50 with the valve chamber 160. This fluid communication 260 opens into the The combustion chamber side end of the valve chamber 160 in the same so that when open control valve 170, the valve body 200, the fluid connection 260 prevents. By a balance of forces acting on the valve body 200 of the control valve 170, the valve body 200 is in the closed position. By a further balance of forces be ^¬ the nozzle needle 60 is also in the closed position. When the actuator 220 is energized, the actuator 220 expands in its longitudinal direction and actuates the control valve 170. As a result, the control valve 170 is opened and the pressure in the valve chamber 160 decreases. As a result of this pressure drop, fluid flows via the outlet throttle 180 into the valve chamber 160. At the same time, less fluid flows via the inlet throttle 140 into the control chamber 150, so that the pressure in the control chamber 150 decreases, but less so compared to the valve chamber 160. For example, the pressure drops to 1300 to 1400 bar. This ensures that the On the nozzle needle 60 acting force ratio is changed so that the nozzle needle 60 lifts from its associated needle valve seat and fluid exits through the injection ports 80. The valve body 200 is thereby in a position in which it shoots the fluid connection 260, so that no fluid from the recess 50 can enter the valve chamber 160.

When the actuator 220 is discharged, the control valve 170 closes, pushing the valve body 200 back into its valve seat. At the same time, the fluid connection 260 between the recess 50 and the valve chamber 160 opens due to the axial movement of the valve body 200. As a result, the pressure in the valve chamber 160, in the control chamber 150 and in the recess 50 builds up again. The force acting on the nozzle needle 60 force ratio ensures that the nozzle needle 60 is moved back to its closed position.

In order to ensure a sufficiently high closing force for closing the control valve 170, the valve body 200 is closed. In addition directly to the control chamber 150 and coupled via this the fluid connection 260 with the recess 50. This will be described with the aid of FIG. Figure 2 shows a schematic, enlarged sectional view of the valve plate 190 with the control valve 170 and the throttle plate 130 with the aperture 120, the inlet throttle 140, the outlet throttle 180 and the fluid connection 260. Furthermore, the control chamber 150 is partially shown.

The valve body 200 is disposed in the valve space 160 and has the shape of a valve mushroom. The valve chamber 160 is at its Aktornahen end with the fluid drain 210 in a couplable fluid connection, at its aktorfernen end is the valve chamber 160 via the outlet throttle 180 with the control chamber in fluid ^¬ connection. In addition, the fluid connection 260 exists between the valve chamber 160 and the recess 50 at the actuator-remote end of the valve chamber 160. The valve body 200 is accommodated axially displaceably in the valve chamber 160 and has the shape of a valve mushroom. Via a coupling element 270, which is coupled to the actuator 220, the elongation of the actuator 220 is transmitted to the valve body 200 when the actuator 220 is energized, which then against the closing force F of a spring 300, which urges the valve body 200 in the valve seat of this is lifted.

As a result, the connection between the fluid outlet 210 and the valve chamber 160 is released and there is a pressure drop in the valve chamber 160, which affects the control chamber 150 via the outlet throttle 180, whereby the pressure on the nozzle body 40 in the control chamber 150 also drops and the nozzle needle 60th therefore opens.

At the same time, the valve body 200 is designed in such a way that, with an elongation of the actuator 220 which is transmitted by means of the coupling element 270, it displaces the valve body 200 in the axial direction toward the actuator-distal end of the valve body 200

Valve space 160 causes. In this case, the valve body 200 closes the opening into the actuator remote end of the valve chamber 160

Fluid connection 260, so that the hydraulic coupling between the valve chamber 160 and the recess 50 is completely prevented. This can be closed via the valve body 200 fluid connection 260, which may be formed as a bypass throttle 260, thus ensuring a minimum leakage during operation of the injection valve 10. Further, it is possible when closing the bypass throttle 260 at the piezo additional information, eg. B. in the form of sensor signals or force pulses, which can be used for the injection quantity controls. By the hydraulic coupling by means of the bypass throttle 260, an additional closing force on the valve body 200 for closing the control valve 170 can be achieved. When closing the nozzle needle 60, the pressure in the control chamber 150 builds up faster because in addition via the bypass throttle 260 pressurized fluid controlled passes into the valve chamber 160, whereby the pressure build-up in the valve chamber 160 by a closing of the control valve 170 and the concomitant interruption of the fluid flow is prevented in the fluid drain 210 and on the other hand, a flow of pressurized fluid through the outlet throttle 180 is prevented in the valve chamber 160 by the pressure conditions in the valve chamber 160.

In addition, minimal leakage is ensured by the bypass throttle 260 which can be closed by means of the valve body 200. In addition, a spring element 280 is provided in the valve space 160, which acts on the valve body 200 and exerts a force on the valve body 200 in the closing direction of the control valve 170. The spring element 280 serves to securely close the control valve 170 even in the case of a non-pressurized injection valve 10. _n

Reference sign list

10 injection valve

20 injector body

30 fluid inlet

40 nozzle body

50 recess

60 nozzle needle

70 nozzle needle seat

80 injection opening

90 nozzle needle spring

100 nozzle retaining nut

110 combustion chamber seal

120 aperture

130 throttle plate

140 inlet throttle

150 control room

160 valve space

170 control valve

180 outlet throttle

190 valve plate

200 valve body

210 fluid drain

220 actor

230 actuator head plate

240 actuator base plate

250 Bourdon tube

260 fluid connection

270 coupling element

280 spring element

Claims

claims

1. injection valve (10) for injecting fluid in a combustion chamber of an internal combustion engine, comprising,

- An injector body (20), with a fluid inlet (30) for

Supplying pressurized fuel fluid and a fluid drain (210);

- A nozzle body (40), with a fluid inlet (30) hydraulically coupled recess (50), in which a nozzle needle (60) is arranged axially movable, said Dü ^¬ sennadel (60) in a closed position fluid flow through a Injection opening (80) of the nozzle body (40) prevents and otherwise releases;

- A control chamber (150) which is hydraulically coupled to the fluid inlet (30) and the nozzle needle (60);

- A control valve (170) having a valve body (200) and a valve chamber (160) which is hydraulically coupled to the control chamber (150), wherein depending on a closed position of the valve body (200) of the valve chamber (160) with the fluid outlet (210 ) is hydraulically coupled, and

- An actuator (220) which is coupled to the valve body (200) for actuating the control valve (170), characterized in that the valve chamber (160) in addition to the recess (50) in the nozzle body (40) is hydraulically coupled.

Second injection valve (10) for injecting fluid in a combustion chamber of an internal combustion engine according to claim 1, characterized in that the hydraulic coupling of the valve chamber (160) with the recess (50) in the nozzle body (40) in actuated / energized actuator (220) is prohibited.

3. Injection valve according to one of claims 1-3, characterized in that the hydraulic coupling between the valve chamber (160) and the recess (50) of the nozzle body (60) as a bore (260) is formed, which in the region of the valve body ( 200) opens into the valve chamber (160).

4. Injection valve according to claim 3, characterized in that the valve body (200) with actuated actuator (220), the bore (260) closes and thus prevents the hydraulic coupling between the valve chamber (160) and the recess (50).

5. Injection valve according to one of claims 3 or 4, characterized in that the bore is designed as a bypass throttle (260).

6. Injection valve according to one of the preceding claims, characterized in that the fluid inlet (30) to the recess (50) of the nozzle body (40) is formed with a diaphragm (120).

7. An injector according to claim 6, characterized in that the diaphragm (120) has a diameter of at least 0.6 mm.

8. Injection valve according to one of the preceding claims, characterized in that between the fluid inlet (30) and the control chamber (150) an inlet throttle (140) is provided.

9. Injection valve according to one of the preceding claims, characterized in that a spring element (300) is provided which a force on the valve body (200) in

Closing direction of the control valve (170) exerts.