EP2052145B1 - Vibration- and pulsation-attenuated electropneumatic converter - Google Patents

Abstract

An electropneumatic converter for connection with an exhaust recirculation valve in a motor vehicle. The electropneumatic converter includes a vacuum port and an atmospheric pressure port configured to connect with a valve chamber using a valve device, wherein a mixed pressure is formed in the valve chamber and supplied to a mixed pressure port. An armature is affixed to a valve body of the valve device movable in an axial direction, the valve body being connected to a suspension device, wherein the armature is displaceable in the axial direction using a solenoid. The electropneumatic converter also includes a damping element configured to dampen the axial movement of the armature and the valve device affixed thereto. The damping element includes at least one of an elastomer or a foamed material.

Description

The invention relates to an electropneumatic converter, which is used for example for pneumatic control in motor vehicles by a mixing pressure is formed from the intake pressure of an internal combustion engine and the atmospheric pressure, which is a consumer, for example, an exhaust gas recirculation valve supplied.

Such a converter is for example in DE 41 10 003 C1 described. This has three ports, wherein the first port is subjected to a negative pressure and the second port to atmospheric pressure and the third port to a mixing pressure of the first and the second port, which is supplied to a consumer, such as an exhaust gas recirculation valve. Further, this converter has a valve device and a fixedly connected thereto plunger armature, which is displaceable by an electromagnet, so that the position of the valve device can be changed and the consumer supplied mixing pressure can be controlled. The valve device and the anchor connected to it are suspended in the axial direction movable on a membrane.

A disadvantage of such a pressure transducer that the armature and the valve device can oscillate freely in the axial direction, with undesirable vibrations caused in particular by engine vibrations or by pressure pulsations on the part of the connected components can be. This undesirable effect occurs in conjunction with negative pressure pulsations.

Furthermore, pulsations may occur in a state in which the electromagnet is not traversed by a current and thus can not transmit force to the plunger armature and the valve device. Unwanted vibrations of the plunger armature and the valve device lead to disturbances in the operation of the internal combustion engine.

Other transducers according to the preamble of claim 1 are also made DE 42 05 565 A . DE 197 55 956 A and US 4 988 074 A known.

The object of the invention is to provide an electropneumatic pressure transducer, which allows improved, trouble-free operation of the internal combustion engine.

The object is achieved according to the invention by the features of claim 1.

For damping the axial movement of the armature and the valve device connected to it, a damping element is provided. As a result, undesired vibrations of the armature and the valve device connected to it in the axial direction are effectively avoided, so that a trouble-free operation of the internal combustion engine is possible.

In particular, the invention allows a reduction of pulsations in the de-energized state and in the operating range of the electropneumatic converter. Furthermore, the invention leads to a better large and small signal behavior of the electropneumatic converter during the ventilation process.

The damping element may in particular be arranged between the valve device and a housing. Also, the damping element between the armature and an iron core located under the armature can be arranged.

Furthermore, the damping element may be formed, for example, as a membrane.

Regardless of the material used, the damping element, as described above, be mounted at different locations of the electropneumatic transducer, so that a damping of the axial movement of the armature and the valve device connected to it is made possible.

It is particularly preferred to integrate the damping element in the suspension device, through which the valve body and the armature connected to it are suspended in the axial direction movable. For example, the damping element can be realized by integrated in the suspension damping legs, whereby the installation of an additional damping element is eliminated. Furthermore, the damping element can be integrated into other existing components of the electropneumatic transducer, i. In addition to their actual function, these components can also fulfill a damping function with respect to the axial movement of the armature and the valve device connected to it. The use of an additional damping element is not necessary in such an arrangement. The term integrated means in this context that the further component and the damping element are integrally formed, wherein the damping element and the further component are two components which are fixedly connected to each other, or it is in the damping element and the further component to a single component acts, which is monolithic.

Particularly preferred is an arrangement of the damping element at the acted upon by the atmospheric pressure ventilation side of the electropneumatic converter. As a result, the closing process of the valve device can be delayed for a short time, as a result of which the behavior of the electropneumatic converter is improved, in particular in the small signal range becomes. In this case, the valve plate of the bellows closes the vacuum tube, which may be formed in particular as a brass tube, and the ventilation takes place on the bellows over. The force introduced by the damping element on the armature causes the second valve seat integrated in the armature to be closed in a delayed manner. Due to the sealing surface of the bellows, the vacuum connection (negative pressure source / pump) is kept closed as long as possible to allow ventilation. Such an arrangement causes in particular an improved large and small signal behavior during the ventilation process. The connection to the atmosphere should remain open as long as possible. As a result, for example, a negative pressure can be reduced faster. When the differential pressure and the force transmitted to the armature by the solenoid are approximately in equilibrium, the valve plane of the bellows closes both valve seats. Further ventilation is now via the valve seat bypass until the final equilibrium of forces is reached.

In a further embodiment, the damping element may be formed as a damping membrane in the form of an elastomeric ring, in which or in which the armature is mounted.

In the following preferred embodiments of the invention will be explained with reference to figures.

Fign. 1-5

Schnittansichten verschiedener Ausführungsformen des elektropneumatischen Wandlers und

Fign. 1a-5a

Detailansichten der Dämpfungselemente der in den Fign. 1-5 dargestellten elektropneumatischen Wandler.

Show it:

FIGS. 1-5

Sectional views of various embodiments of the electropneumatic converter and

FIGS. 1a-5a

Detailed views of the damping elements in the FIGS. 1-5 shown electropneumatic converter.

According to Fig. 1 For example, an electropneumatic converter has a negative pressure port 10, an atmospheric pressure port 12, and a mixed pressure port 14 which is supplied with a mixed pressure of the negative pressure port 10 and the atmospheric pressure port 12. The mixing pressure is supplied via the mixing pressure connection 14 to a consumer, in particular an exhaust gas recirculation valve.

The valve device 18, 28 has a valve body 18 with a valve plate 28. The valve body is connected via a diaphragm 20 with a housing 32 such that it is movable in the axial direction 30. The membrane 20 is guided in a ring around the valve body 18 and secured in an annular recess of the housing 32 and a housing cover by clamping. Between the valve body 18 and the housing 32 or housing cover, the membrane 20 has a substantially arcuate course. The membrane 20 is also secured to the valve body 18 in a recess which leads around the valve body 18 in an annular manner.

With the valve body 18, an armature 16 is fixedly connected and also movable in the axial direction. The armature 16 comprises a magnetic material and can be moved by applying an electric current to an electromagnet 17.

The electric coil of the electromagnet 17 is surrounded by an iron sheath 38 for bundling the magnetic field lines. Furthermore, an air gap 40 is formed between the armature 16 and the iron sheath 38, in which an adjustable iron core 34 is arranged such that the length of the air gap 40 is variable. In addition, a second iron core 36 is provided, which projects into a recess 37 of the armature 16. Between the first iron core 34 and the armature 16, a cavity 24 is formed.

The mixing pressure, which is supplied via the mixing pressure connection 14 to a consumer, is established in a valve chamber 11, which is delimited by the membrane 20. The mixing pressure results from the pressure which is supplied to the electropneumatic valve via the vacuum connection and the air pressure which is supplied to the electropneumatic valve via the atmospheric pressure connection 12.

By changing the current supplied to the electromagnet 17, accurate control of the mixing pressure supplied to the consumer is possible. A precise adjustment of the air gap 40 is possible by adjusting the iron cores 34,36, so that any effects of mechanical and / or electromagnetic tolerances can be turned off.

According to the FIGS. 1 and 1a the valve plate 28 is integrally formed with the elastomer bellows 19 and thereby resiliently connected to the armature 16. Through the valve plate 28, the vacuum port can be opened and closed.

The essential feature of the electro-pneumatic converter according to the invention is the damping element 26, which according to Fig. 1 is formed as a bellows made of elastomer, and between a valve seat collar 56 and the coil rib 27 is arranged. By this bellows unwanted vibrations of the armature and associated with him valve device in the axial direction are effectively avoided, so that a trouble-free operation of the internal combustion engine is possible.

The same or similar components are described in the following figures with the same reference numerals.

The damping element 26 is according to the FIGS. 2 and 2a formed as part of the membrane 20, and can with this membrane 20 in a Injection molding be made in one piece. Analogous to the FIGS. 1 and 1a the effect of the damping element 26 takes place in that it is supported on one side on the coil rib 27 and on the opposite side introduces a force into the membrane 20 connected to it. The damping element 26 is attached to the ventilation side of the electropneumatic converter, ie, on the side which is directly connected to the atmospheric pressure port 12.

According to FIGS. 2 and 2a the damping element 26 is also disposed within the cavity 22.

In FIGS. 3 and 3a For example, an elastomeric damping element 26 disposed within a cavity 24 formed between the armature 16 and the iron core 34 is shown.

Figures 4 and 4a show in the same place a damping element of a foam body. ,

In a further embodiment according to Fig. 5 and 5a the damping element may be formed as a damping diaphragm 50 and in particular as an elastomer ring, in which or in which the armature 16 is mounted. The elastomeric ring preferably comprises silicone. Alternatively or additionally, the strokes of the armature 16 and the valve means 18, 28 are damped by mounted on the housing 32 stops 44, 46, 48. These are preferably located at the location of the housing 32 to which the valve body 18 moves upon movement in the direction of the force exerted by the diaphragm 20.

By an exact adjustment of the position of the hubverhindernden or Hubmindernden stops 44, 46, 48 and by tuning the spring force or the membrane force, it is possible to realize an excitation acceleration of 20 g. Particularly advantageous is the use of a Damping membrane 50 with a thickness between 2 mm and 3 mm, so that limitations of the functions of the electropneumatic converter, such as characteristic (slope and hysteresis) or dynamics (large and small signal) can be minimized.

Alternatively or additionally, a thicker damping membrane 50 can be used, which has recesses and is thus made more flexible. For receiving the damping diaphragm 50, the valve body 18 has a preferably annular groove 52.

In order to allow a passage in the direction of the atmospheric pressure port 12, the stop 46 has a groove-shaped recess 54 through which ventilation can take place. The stops 46, 48 may be formed, for example, of plastic.

For additional damping of the movement of the valve body 18, a spring 42 may be formed between the valve body 18 and the housing 32. This is inventively used in conjunction with other damping elements 26, 50.

It may be both a single damping element, for example, only on one side of the armature or the valve means may be provided, or even a plurality of damping elements, which are arranged on one or more sides of the armature and the valve means.

Claims (8)

1. An electropneumatic converter for connection with an exhaust recirculation valve in a motor vehicle, comprising
   a vacuum port (10) and an atmospheric pressure port (12) which are connectable with a valve chamber (11) via a valve device (18, 28), so that a mixed pressure is adjusted in the valve chamber (11) and supplied to a mixed pressure port (14); and
   an armature (16) affixed to a valve body (18) of the valve device (18, 28) movable in an axial direction (30), the valve body being connected to a suspension device (20), wherein the armature (16) is displaceable in the axial direction (30) using a solenoid (17),
   characterized by
   a damping element (26) configured to dampen the axial movement (30) of the armature (16) and the valve device (18, 28) affixed thereto, wherein the damping element includes at least an elastomer or a foam or in particular polyurethane.
2. The electropneumatic converter recited in claim 1, characterized in that the damping element (26) is disposed between the valve means (18) and a housing (32).
3. The electropneumatic converter recited in claim 1, characterized in that the damping element (26) is disposed between the armature (16) and an iron core 34).
4. The electropneumatic converter recited in one of claims 1-3, characterized in that the damping element (26) is configured as a membrane, preferably a rolling membrane.
5. The electropneumatic converter recited in one of claims 1-4, characterized in that the damping element (26) is integrated in the suspension device (20).
6. The electropneumatic converter recited in one of claims 1-5, characterized in that an air gap (40) is formed between the armature (16) and an iron casing (38) of the solenoid (17) on a side of the armature (16) opposite the valve means (18, 28), wherein at least one adjustable iron core (34, 36) is disposed to adjust the air gap (40).
7. The electropneumatic converter recited in one of claims 1-6, characterized in that the damping element is configured as a damping membrane (50) in a form of an elastomer ring supporting the armature.
8. The electropneumatic converter recited in one of claims 1-7, characterized in that the housing (32) is configured with stroke-limiting abutments (44, 46, 48) to dampen the axial movement (30) of the armature (16) and the valve means (18, 28).

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