EP1047897A1

EP1047897A1 - Controllable leaf valve

Info

Publication number: EP1047897A1
Application number: EP99953939A
Authority: EP
Inventors: Michael Schebitz; Martin Pischinger; Markus Duesmann
Original assignee: FEV Motorentechnik GmbH and Co KG
Current assignee: FEV Europe GmbH
Priority date: 1998-11-13
Filing date: 1999-10-26
Publication date: 2000-11-02
Also published as: DE19982383D2; JP2002530602A; US6425356B1; DE19982292D2; WO2000029772A1; DE19852389A1; JP2002530564A; WO2000029734A1

Abstract

The invention relates to a valve for influencing a flowable medium, notably a gas. Said valve comprises at least one flow channel (4) whose opening is configured as a valve seat (7), at least one valve body (8) which is arranged at the free end of a spring-loaded arm (9) fixed at its other end, and at least one electromagnet (11, 12) which acts on an area (13) of the spring-loaded arm (9) configured as an armature and which when a current is applied moves the valve body (7) by means of a control device (25) into its closed or open position.

Description

Description: Controllable reed valve

description

Pressure-controlled inlet valves and pressure-controlled outlet valves, which are designed as so-called tongue valves, are generally used on a piston compressor. Controlling the volume flow with these previously known valves is only possible with piston compressors with several cylinders and also only in rough steps by cylinder deactivation. A valve arrangement of this type can be found, for example, in DE-A-23 57 578, which has tongue valves designed as check valves both on the inlet side and on the outlet side. By means of an actuating device acting on the tongues of the inlet valves, it is possible to keep it open on one or more cylinders, so that the medium in question is not conveyed and compressed by the cylinder in question.

Another disadvantage of the previously known valve arrangement is that its opening and closing movements cannot be influenced. In particular with the exhaust valves, these only open and only as far as is possible during the compression stroke due to a correspondingly high overpressure in the cylinder interior opposite the pressure side of the

System is possible. As soon as the pressure equilibrium between cylinder interior and pressure chamber is approximately set towards the end of the compression stroke, the spring tongue is moved in the closing direction due to its own spring force. Here it cannot be avoided that due to a certain damping by the medium conveyed, the valve tongue does not immediately come to rest on the sealing surface. In addition, bouncing processes can also occur, so that the valve is only finally closed when the pressure level in the pressure chamber is already slightly below. The inevitable consequence of this is that a corresponding volume of the medium to be compressed is returned to the cylinder chamber from the pressure chamber. flows back and the efficiency of the compressor is reduced.

In addition to compressor construction, there are also other applications for valves that have to react very quickly to existing pressure differences in order to be able to make targeted use of an existing pressure drop.

The invention has for its object to provide a fast switching tongue valve which avoids the disadvantages described above.

According to the invention, the object is achieved by a valve for influencing a flowable medium, in particular a gas, with at least one flow channel, the

Mouth is designed as a valve seat and with at least one valve body, which is arranged at the free end of a resilient arm clamped at the end, and with at least one electro-magnet, which acts on an area of the resilient arm designed as an armature and which, when energized via a control device, the valve body in moves its closed position and / or its open position. A valve designed in this way has the advantage over the conventional tongue valves that not the entire valve tongue and its bearing surface on the valve plate serves as a valve seat, but a separate valve body is arranged which interacts with the mouth of the flow channel designed as a valve seat. Since part of the resilient arm is designed as an armature, depending on the circuit, the movement of the valve body can now be influenced in a targeted manner and the switching times of the valve can be influenced. When closing under the influence of the magnetic force, for example, bouncing processes can be prevented, especially since the valve body on such a reed valve has only a small mass. Depending on the design, the valve can be fully opened or closed in a targeted and practically independent of pressure. In a first embodiment of the invention it is provided that the valve body with its resilient arm is designed as a check valve and is evidently closable by the pressure of the flowing medium and can be closed by the action of the spring force and the magnetic force. In this embodiment, the valve according to the invention operates with respect to its opening process like a normal check valve. For the closing process, however, the closing speed but also the closing time can be influenced by the targeted activation of the magnetic force. It is thus possible to initiate the closing movement if there is still a residual flow in the flow channel with a small pressure difference.

In another embodiment of the arrangement according to the invention it is provided that the valve body is designed with its resilient arm as a check valve and is evident from the action of the magnetic force against the spring force. In this embodiment of a check valve, it is possible to open the valve by energizing the associated electromagnet when a pressure equilibrium is present on both sides of the valve body. The further advantage of this arrangement is that the valve opening is specifically opened to the full cross section at the beginning of the flow, so that the friction and the associated heating of the flowing medium is reduced.

However, the valve according to the invention also allows a configuration as a check valve, in which two electromagnets directed towards one another are provided, so that both the opening movement and the closing movement can be influenced when the electromagnets are suitably energized.

In a further embodiment of the invention, two electromagnets arranged at a distance from one another are provided, which can be energized alternately via the control device and the valve body can be moved from a central position to the fully open and the fully closed position by magnetic force against the action of the spring force. With appropriate control and with appropriate energization of the electromagnets, this arrangement allows the valve to be opened and closed in a specifically controllable manner with very short switching times and high switching frequency, both the opening and the closing beginning being predeterminable in each case via the corresponding control of the energization. In this arrangement, the spring arm has practically only the meaning of a return spring which accelerates the release of the armature part from the pole face of the holding magnet after the current has been switched off. The spring arm also serves as a support for the anchor. For example, when used as an outlet valve on a piston compressor, the spring stiffness of the spring arm can be specified very low, since in the open position the medium flowing through the valve seat also exerts a force effect in the opening direction for the valve body. Since the closing process for a piston compressor takes place with pressure equilibrium or only a low flow of the medium, the spring force as the closing force is also of secondary importance here, since the magnetic force during the closing process begins to act on the spring arm at a time when the flow force acting in the opening direction sinks towards zero and when the valve is closed the higher pressure around the pressure chamber keeps the closing body in the closed position.

In an advantageous embodiment of the invention it is provided that the armature is formed by a widened partial surface of the spring arm. This results in a significant reduction in the masses to be moved and, on the other hand, it is possible to arrange the electromagnets required for actuating the valve body with a small gap distance from the armature. In an embodiment of the invention it is further provided that a base plate separating two pressure chambers is provided, which has a plurality of flow channels arranged at a distance from one another and that a spring arm with armature and valve body is provided for each flow channel at least on one side of the base plate and that at least one magnet intended to actuate all anchors. With such an arrangement, it is possible to provide a plurality of flow channels in a small installation space which, with a single diameter of only 10 mm, enable a throughput of the order of 1,000 to 1,600 l / h per flow channel.

Further refinements and applications according to the invention can be found in the subclaims and the description below in conjunction with schematic drawings of exemplary embodiments. Show it:

1 shows a basic design of a valve,

2 shows an application for a piston compressor,

Fig. 3 is a plan view of the valve assembly. the section III-III in Fig. 2,

Fig. 4 shows a modification of the spring arrangement. Fig. 3,

Fig. 5 shows an application as a control valve for generating a negative pressure with the aid of pressure fluctuations.

1 shows a first pressure chamber 1 and a second pressure chamber 2, which are separated from one another by a partition 3. The two pressure chambers 1 and 2 are connected to one another via a flow channel 4 arranged in the dividing wall 3 and through which a flowable medium, for example a gas, flows as a result of periodic pressure differences in the direction of the arrow 5. The mouth 6 of the flow channel 4 into the pressure chamber 2 is designed as a valve seat 7, for example in the form of a conical or dome-shaped recess.

A valve body 8 is assigned to the valve seat 7 and is arranged at the free end of a resilient arm 9 clamped at the end.

The valve also has two electromagnets 11 and 12 with their pole faces 10 at a distance from one another and aligned with one another. The area 13 of the resilient arm 9 assigned to the pole faces 10 serves here as an anchor.

In the embodiment shown here, the arrangement is such that when electromagnets 11, 12 are de-energized, the region 13 of the resilient arm 9 serving as an armature is in a central position, so that the valve body 8 is also at an average distance from the valve seat 7 . The underlying electromagnet 11 serves as a closing magnet, while the overhead electromagnet 12 as

The opening magnet is used so that when the electromagnets are energized accordingly, the valve body 8 is either placed on the valve seat 7 and the valve closes or is lifted off the valve seat 7 and the valve is fully opened.

If the pressure chamber 2 has a higher pressure than the pressure chamber 1, then the valve body 8 is pressed onto the valve seat 7 in the manner of a check valve or tongue valve, even without support from the magnetic force of the closing magnet 11. If the pressure of the medium in the pressure chamber 1 is now increased, the medium will flow from the pressure chamber 1 into the pressure chamber 2 after the pressure equilibrium has been exceeded. In order to bring about a complete valve opening regardless of the level of the excess pressure in the pressure chamber 1, the opening magnet 12 is energized, for example, shortly before or when the pressure equilibrium is reached, so that at the beginning of the building overpressure in the pressure chamber 1, the flowable medium can flow through the flow channel 4 into the pressure chamber 2.

If the pressure in the pressure chamber 1 drops again, the opening magnet 12 can be de-energized shortly before and ultimately when the pressure equilibrium is reached and the closing magnet 11 can be energized, so that the valve body 8 is retracted by the action of the magnetic force on the valve seat 7 and so on to prevent the medium from flowing back from the pressure chamber 2 into the pressure chamber 1, which is now at a falling pressure.

Since this valve arrangement has very low vibrating masses, very fast response times during the opening and closing process are possible, but actuation with a very high switching frequency is also possible. From the above description it can easily be deduced that the spring arm 9 can also be clamped with its valve body 8 in such a way that the spring force presses the valve body 8 onto the valve seat 7. This provides a non-return valve that can be opened in a controllable manner with the help of the opening magnet 12 and that can be closed by energizing the closing magnet 11 in a very short switching time, if necessary, against any residual flow in the flow channel 4. Depending on

In use, however, it is also possible to provide only one opening magnet 12 or only one closing magnet 11, it being possible in turn to design the check valve so that, as described above, it is closed in the rest position or is open in the rest position. Of

The advantage here is that a very small distance can be set between the two pole faces and thus a direct effect of the magnetic force on the armature is possible.

In Fig. 2 the application of the valve described above is shown schematically as an outlet valve on a piston compressor. As can be seen in FIG. 2 in connection with FIG. 3 lets are in a partition 3.1 on the cylinder head 14, several flow channels 4, for example six flow channels, as shown in the illustration. Fig. 3 reveals, evenly distributed over the circumference. Accordingly, six spring arms 9 with valve bodies 8 are also provided. As the

Supervision acc. Fig. 3 shows, the spring arms are arranged radially inward and firmly clamped to the cylinder head 14. As the supervision acc. Fig. 3 shows, in this embodiment, the spring arms 9 are formed wider in their associated with the electromagnets 11 and 12 and serving as an anchor area 13, so that despite the manufacture as a stamped part, each spring arm is provided with a discrete anchor. With this configuration, it is not necessary to provide a separate opening magnet and closing magnet for each spring arm, but it is possible to provide a correspondingly designed ring magnet both as an opening magnet and as a closing magnet, as can be derived from FIG. 2.

Above the partition 3 there is a head part 15 which on the one hand has an annular space 2.1 covering the mouths of the flow channels 4, which is provided with an outlet opening 16 and which, according to the description in accordance with FIG. Fig.

1 defines the pressure chamber 2. Coaxial to the cylinder axis 17, a central space 18 is provided above the partition 3, which is provided with an inflow channel 19. The central space 18 stands above an inlet valve designed as a poppet valve

20 with the cylinder chamber 1.1 in connection, which according to the description acc. Fig. 1 has the function of the pressure chamber 1. The inlet valve 20 is connected to a controllable actuator 21, so that the inlet valve 20 can be opened during the intake stroke and closed during the compression stroke.

The actuator 21 for the inlet valve 20 can also be configured here as an electromagnetic drive, which also how the closing magnet 11 and the opening magnet 12 can be controlled via a control device.

In order to be able to provide sufficient strokes for the valve body 8 even with smaller cylinder diameters, starting from the radial arrangement according to FIG. 3, a radial-tangential alignment of the spring arms 9 is carried out, as is shown with reference to FIG. 4 in a top view corresponding to FIG. 3. The widened portions 13 of the spring arms 9 functioning as anchors can, however, also be designed as circular sections concentric with the cylinder axis 17, so that ring-shaped opening and closing magnets can also be provided in this arrangement.

Since the structure and function of the valve described with reference to FIG. 1 allows very short switching times due to its small movable mass, it is also possible to use such a valve to generate a negative pressure with the aid of a pulsating gas flow fluctuating around a zero level in its pressure to use.

While in piston internal combustion engines with a change in the air supply through a throttle valve in the air intake tract with a corresponding position of the throttle valve, there is a negative pressure which can then be used to generate a negative pressure, for example for a brake booster, this possibility does not exist in the case of throttle-free engines. In throttle-free engines, however, the periodic opening of the gas inlet valves in the air intake duct creates a pulsating pressure

Air flow that is also below a zero level.

Now, as shown with reference to FIG. 5, a valve arrangement of the type described with reference to FIG. 1 is connected to the air intake tract 22 of a piston internal combustion engine in such a way that the air intake tract 22 pressurizes the pressure chamber 1 in accordance with the illustration. Fig. 1 forms and over a Flow channel 4.1 is connected to a system 26 that can be actuated by negative pressure, shown only schematically here, then in the illustrated assignment of the valve body 8.1, which is pressed onto the valve seat 7.1 via the spring arm 9.1 in the closed position, by actuating an electromagnet 12.1 functioning as an opening magnet, the valve in each case are then opened when a vacuum is present in the air intake duct 22 in the region of the junction 7.2 of the inflow duct 4.1 to the valve. As soon as this relative pressure pulse drops below a predeterminable level, the opening magnet 12.1 is de-energized, so that under the action of the spring force of the resilient arm 9.1, the valve body 8.1 rests on the valve seat 7.1 and the valve closes. The subsequent increase in pressure in the air intake tract supports the closing action, so that it is ensured that the valve opens only when the pressure drops and the vacuum device 23, which acts as pressure chamber 2, is evacuated accordingly.

The electromagnet 12.1 can be energized via a corresponding control device 25, which detects the pressure profile of the air flow via a pressure transmitter 27 in the air intake tract 22. The pressure transmitter 27 should be arranged as close as possible to the inflow duct 4.1 in order to detect the pressure level directly at the junction with the vacuum device 23.

Claims

Expectations

1. Valve for influencing a flowable medium, in particular a gas, with at least one flow channel (4), the mouth of which is designed as a valve seat (7), and with at least one valve body (8), which at the free end of a resilient arm clamped at the end ( 9) is arranged, and with at least one electromagnet (11, 12) which acts on an area (13) of the resilient arm (9) designed as an armature and which, when energized via a control device (25), the valve body (7) into it Closed position or its open position moves.

2. Valve according to claim 1, characterized in that the valve body (7) with its resilient arm (9) is designed as a check valve and is evidently closed by the pressure of the flowing medium and by the action of the spring force and the magnetic force.

3. Valve according to claim 1 or 2, characterized in that the valve body (7) with its resilient arm (9) is designed as a check valve and is evident by the action of the magnetic force against the spring force.

4. Valve according to one of claims 1 to 3, characterized in that two spaced electromagnets (11, 12) are provided, which can be energized alternately via the control device (25), the valve body (7) from one The middle position can be moved by magnetic force against the action of the spring force in the fully open and in the fully closed position.

5. Valve according to one of claims 1 to 4, characterized in that the armature is formed by a widened partial surface (13) of the resilient arm (9).

6. Valve according to one of claims 1 to 5, characterized in that the armature is arranged between the clamping end of the arm (9) and the valve body (7).

7. Valve according to one of claims 1 to 6, characterized in that a two pressure chambers (1, 2) separating partition (3.1) is provided, which has a plurality of spaced-apart flow channels (4) and that each flow channel (4) a spring arm (9) with armature and valve body (8) is provided on each side of the partition (3.1) and at least one magnet (11, 12) is provided for actuating all armatures.

8. Valve according to one of claims 1 to 7, characterized by the use as an inlet valve and / or outlet valve on a piston compressor.

9. Valve according to one of claims 1 to 8, characterized by the use as a pressure rectifier for generating a negative pressure in a pressure chamber (2) in connection with a pulsating, positive and negative pressure gas stream.

10. Valve according to one of claims 1 to 9, characterized in that the control device (25) for energizing the electromagnets (11, 12) is at least connected to a pressure transmitter P (27).