EP1913241A1

EP1913241A1 - Pneumatic pressure control valve

Info

Publication number: EP1913241A1
Application number: EP06762542A
Authority: EP
Inventors: Uwe Meinig; Stephan Ahlborn
Original assignee: Ing Walter Hengst GmbH and Co KG
Current assignee: Ing Walter Hengst GmbH and Co KG
Priority date: 2005-08-06
Filing date: 2006-07-12
Publication date: 2008-04-23
Anticipated expiration: 2026-07-12
Also published as: ATE414843T1; WO2007017033A1; DE502006002141D1; DE202005012403U1; EP1913241B1

Abstract

The invention relates to a pneumatic pressure control valve (1) for controlling the pressure in the crankcase of an internal combustion engine. To this end, a regulating diaphragm (2) is provided inside the pressure control valve (1) whereby enlarging or reducing the size of the passage through a first larger outflow opening (15) and through at least one second smaller outflow opening (16) of the pressure control valve (1) that is separate and located at a distance from the first opening. The novel pressure control valve (1) is characterized in that: the regulating diaphragm (2) is acted upon by a single control spring (3); the spring force can be introduced by the single control spring (3) both into a diaphragm area (25), which interacts with the larger outflow opening (15), as well as into a diaphragm area (26) interacting with the at least one outflow opening (16); diaphragm area (25), which interacts with the larger outflow opening (15), can be displaced relative to the remaining regulating diaphragm (2) perpendicular to the diaphragm plane and which has an area equal to no greater than 1/5 of the total area of the regulating diaphragm (2); the regulating diaphragm (2) has an inner roll fold (21) around the diaphragm area (25) interacting with the larger outflow opening (15), and; the diaphragm area (26) of the regulating diaphragm (29) interacting with the at least one smaller outflow opening (16) is located outside of the inner roll fold (21).

Description

Description :

Pneumatic pressure control valve

The present invention relates to a pneumatic pressure control valve for automatic control of the pressure in the crankcase of an internal combustion engine, wherein the pressure control valve is arranged in the course of a crankcase ventilation line, the passage of which by means of the pressure control valve in dependence on the differential pressure between a reference pressure and an applied pressure at an inlet of the pressure control valve automatically variable is, is provided in the pressure control valve, a clamped in a valve housing actuating diaphragm which is acted upon on the one hand by the reference pressure and on the other hand by the gas pressure and spring force, whereby when changing the differential pressure between the adjoining the control diaphragm areas the control diaphragm is adjusted and the control diaphragm the Passage through a first, larger outflow opening and through at least one separate, spaced apart second, smaller, parallel flow-through outflow opening the pressure control valve increased or decreased, wherein at decreasing pressure at the inlet of the pressure control valve by the control diaphragm first the larger outflow opening and only then the smaller outflow opening is closed.

With regard to the crankcase ventilation of modern internal combustion engines, the statutory and resulting as a result of the technical requirement that in the crankcase regardless of the pressure in the intake tract of the internal combustion engine and regardless of the volume or mass flow of the crankcase ventilation gas in all Betriebszust- stände or characteristic areas of the internal combustion engine, taking into account a pressure drop in a usually provided oil mist a negative pressure in a predetermined pressure range the practice z. B. between 0 and about 30 hPa. In order to keep the pressure in the crankcase as constant as possible with varying negative pressures in the intake tract and different volume flows of the crankcase ventilation gas, pressure control valves are predominantly used in both gasoline engines and diesel engines in which an outflow cross section depends on a pressure difference acting on a control diaphragm controlled from the valve and thus the crankcase pressure is maintained at a more or less constant value. A high control quality and thus a high degree of independence of the crankcase pressure from the pressure in the intake tract and the flow rate of the crankcase ventilation gas results in pressure control valves with a large area ratio between the control diaphragm surface and regulated by the control diaphragm Abströmquerschnitt from the pressure control valve. However, with regard to the total pressure loss across the pressure regulating valve, the outflow cross-section must not be too small. At the same time, the increasingly limited space requirements and the cost pressure force the development of pressure control valves with small construction dimensions, whereby the possible area of the control diaphragm is limited.

From DE 101 55 176 Al a pressure control valve of the type mentioned is known. In this known pressure control valve, the first outflow opening is a first Regelfeder and the second outflow opening assigned its own, second control spring. Each control spring exerts on itself on the control diaphragm in each case an opening force acting force. The first control spring should act only on a first membrane area and the second control spring act only on a second, different membrane area. A disadvantage is to be regarded in this known pressure control valve that, due to the use of two separate control springs, a relatively large number of items, in particular two different control - springs needed. This leads to an increased manufacturing and assembly costs. In addition, it is unfavorable that when using multiple control springs whose tolerances add in the worst case so that a relatively large dispersion in the control characteristic, which has the pressure control valve in total, results. Finally, disturbing effects of the springs on the respective non-associated membrane area arise when the springs and the respective associated membrane areas are not sufficiently widely spaced from each other, - but a large distance is difficult or impossible to comply because of the usual space limitations in practice.

Another pressure regulating valve is known from DE 102 49 720 Al. This pressure regulating valve is specially designed for an internal combustion engine with a turbocharger. In an internal combustion engine with a turbocharger, crankcase ventilation must be connected to the intake tract upstream of the turbocharger both via a first vent line section and to the intake section downstream of the turbocharger via a second vent line section. The pressure control valve described here has a valve seat which cooperates with a valve body and has a first outlet channel and a second outlet channel, with one outlet opening in each case. Gang channel is connected to one of the two aforementioned areas of the intake upstream or downstream of the turbocharger. Within the pressure control valve, the second output port is concentrically disposed about the first output port. In addition, a separate non-return valve is arranged in each output channel. When the turbocharger is in operation, venting takes place in the intake tract upstream of the turbocharger; If the turbocharger is not in operation, the venting takes place in the area of the intake tract downstream of the turbocharger. In this pressure regulating valve, therefore, depending on the turbocharger operating state, either only the first outlet channel or alternatively only the second outlet channel is flowed through by the crankcase ventilation gas. Thus, while this known pressure control valve provides an automatic choice of the area of the intake tract into which the crankcase ventilation gases are introduced, this pressure control valve does not provide an improved control characteristic in view of the requirements set forth above, which are generally made to pressure control valves of modern internal combustion engines.

EP 0 471 142 B1 discloses a further pressure regulating valve for installation in a venting line on an internal combustion engine, in particular between the crankcase and the intake tract. This pressure regulating valve has a valve housing, which is composed of a cup-shaped housing lower part and a housing cover. The housing has an opening into the lower housing inlet and a branch opening from the lower outlet spout, whose centrally disposed within the valve housing end portion is formed as a valve seat. Furthermore, the valve has a sealed at its edge in a groove between the housing cover and the lower housing part clamped control diaphragm, which Valve housing divided into a valve chamber and connected via a ventilation duct with the atmosphere ventilation chamber. In this case, the membrane has a valve seat facing the valve end at the end of the valve. Furthermore, a compression spring is provided, which is supported on the bottom of the housing base and exerts a force on the membrane in the direction of the housing cover. Furthermore, it is essential in this pressure control valve, that between the valve plate of the diaphragm and the first valve seat on the lower housing part, an intermediate valve is arranged, which has a second valve seat, which faces the membrane and cooperates with the valve plate of the membrane. In addition, the intermediate valve has a valve plate which faces the valve seat of the housing base and cooperates therewith, wherein the intermediate valve is arranged on the membrane such that an axial relative movement between the diaphragm and the intermediate valve is possible. Preferably, a hollow cylindrical part is arranged on the membrane, which is provided on its jacket with openings and in which the intermediate valve is arranged. In addition, a further compression spring is preferably arranged between the diaphragm and the intermediate valve, which in the idle state holds open the second valve formed by the intermediate valve and the valve plate of the diaphragm.

Although the desired, good control characteristic of the pressure control valve by means of the use of the two valves, namely the main valve and the intermediate valve is achieved with this known pressure control valve, but this advantage is associated with a very high cost of items and a correspondingly high installation costs. Since here too two compression springs are preferably used as control springs, the problem of an unfavorable superposition of spring tolerances also occurs here, plus further component tolerances due to the many individual parts.

For the present invention, therefore, the task of creating a pressure control valve of the type mentioned above, which avoids the disadvantages set out and in which a high design quality and reliable operation can be achieved with a simple design with few items and low assembly costs and low tolerances ,

The solution of this object is achieved according to the invention with a pressure control valve of the type mentioned, which is characterized in that the control diaphragm is acted upon by a single control spring to generate the spring force, that by the single control spring, the spring force in both a cooperating with the larger outflow membrane area can also be introduced into a membrane region cooperating with the at least one smaller outflow opening, that the membrane region which interacts with the larger outflow opening is adjustable relative to the rest of the control membrane perpendicular to the membrane plane and has an area which is at most 1/5 of the total area of the control membrane, in that the control membrane has an inner blind around the membrane area cooperating with the larger outflow opening, and that the membrane area of the control membrane interacting with the at least one smaller outflow opening is outside the inner rolled fold lies.

The pressure control valve according to the invention has the advantage of a favorable control characteristic, because the crankcase pressure at high flow rates of the crankcase ventilation gas and low pressure applied to the pressure control valve pressure differences through the large outflow opening is regulated. If there is a drop in the pressure in the crankcase, the control diaphragm initially closes against the spring force of the control spring of the pressure control valve by axially approaching the larger outlet opening. If there is then a further drop in the crankcase pressure, the control diaphragm is adjusted with further deformation of the same single control spring and deformation of the control membrane in itself so that now also narrowed the at least one smaller outlet opening in its cross section and is closed in the limit. Since the remaining cross-section of the smaller outflow opening used for the closed-loop larger discharge port is smaller than the cross-section of the larger outflow opening, a favorable area ratio between the control diaphragm surface and the surface of the outflow cross section of the smaller outflow opening is now achieved even with small surface dimensions of the control diaphragm ensures a desired good control characteristic and high control quality. This statement applies in particular against the background that a serious reduction in the effective area of the control diaphragm and thus the force of the control diaphragm after placing the membrane area cooperating with the larger outflow opening is prevented by the relative mobility between the membrane areas cooperating with the different outflow openings. As a result, the pressure regulating valve, despite its particularly simple structure largely independent of the negative pressure in the intake tract holds the crankcase pressure in a desired, prescribed pressure range. Thus, the pressure control valve according to the invention allows a compact design with a relatively small area of the control diaphragm. Since, for the pressure control valve according to the invention, the control diaphragm can be deformed both as a whole and deformed in a defined way, ie in its different, different outflow openings. gene assigned areas must be adjustable relative to each other, the control diaphragm around the cooperating with the larger outlet opening membrane area around an inner rolled fold, wherein the cooperating with the at least one smaller discharge opening membrane region of the control membrane is located outside of the inner roll fold. This advantageously results in a low loss of effective membrane area after placement on the larger outflow opening, since the remaining membrane effective area is still large. The inner roll fold provided in the control membrane ensures that an inner region of the control membrane located inside the inner roll fold and an outer region of the control membrane lying outside the inner roll fold can be adjusted relative to one another in a defined and reproducible manner, wherein the various Membrane areas do not interfere with each other in an adjustment relative to each other. Instead of the roll fold can be provided to achieve the same function and equivalent means in the membrane, for example, areas of different hardness, which can be produced with two-component material, or material dilutions for targeted local increase in the flexibility of the membrane or a bellows. Furthermore, it is particularly advantageous that the pressure control valve according to the invention requires only a single control spring. The pressure control valve thus comes with a very small number of items, which ensures easy and cost-effective production and installation. In addition, it is thus avoided that tolerances of several components subject to tolerances, such as springs, unfavorably add up to an undesirably large total tolerance.

An even better control behavior can be achieved if the diaphragm area which is connected to the larger outflow opening cooperates, has an area which is at most 1/8 of the total area of the control diaphragm. The effective area reduction of the control membrane after closing the larger outflow opening is kept even lower.

A preferred embodiment of the invention provides that seen in section parallel to the control diaphragm, the valve housing is round. This shape contributes to a compact design and avoids the need for a stretched or elongated valve housing which would generally be more difficult to accommodate in the area of an internal combustion engine.

A further development proposes that the larger outflow opening centrally in the valve housing and the smaller outflow opening is arranged eccentrically in the valve housing. This arrangement also contributes to a compact, space-saving design.

An alternative embodiment proposes that in addition to the larger outflow opening are provided symmetrically to and radially outside of this two or more smaller outflow openings. This symmetrical arrangement has advantages, in particular with regard to the design of the control diaphragm, since in this embodiment the control diaphragm itself can also be implemented symmetrically. This simplifies and reduces the production of the control diaphragm and avoids errors in the assembly of the pressure control valve. In addition, this results in symmetrical forces acting on the control diaphragm, which is advantageous for their adjustment and deformation and thus for the function of the valve. Furthermore, it is preferably provided that with two or more smaller outflow openings, the cross-sectional area of the larger outflow opening is greater than the cross-sectional area sum of the two or more smaller outflow openings. In this way, it is reliably ensured that, even when the valve is designed with a plurality of smaller outflow openings when the larger outflow opening is already closed by the control diaphragm, the favorable area ratio between the area of the control diaphragm and the entire cross-sectional area of the two or more is advantageous for the high control quality results in smaller outflow openings.

A preferred embodiment is characterized in that the at least one smaller outflow opening is bounded by a cooperating with the control diaphragm sealing surface, seen in the closing direction of the adjusting diaphragm behind a likewise cooperating with the control diaphragm, the larger outflow opening bounding sealing surface. With this embodiment, it is achieved that, when the control diaphragm first moves in the closing direction as a whole, it initially only comes into abutment against the sealing surface, which surrounds the larger outflow opening; only by a further adjustment and deformation of the control diaphragm, even now against the force of the same control spring, the control diaphragm also reaches the sealing surface, which defines the at least one smaller Abströmδffnung. In this way, the desired two-stage control behavior is effected with little effort.

Specifically, the sealing surface of the at least one smaller outflow opening preferably lies behind the sealing surface of the larger outflow opening by 0.2 to 1.0 mm, preferably by 0.3 to 0.6 mm. As can be seen here, In practice, therefore, very small measures in the differentiation of the position of the two sealing surfaces are sufficient to reliably achieve the desired function. In this case, this stage can advantageously be generated relatively accurate tool falling.

In order to keep the control membrane as simple as possible and thereby cost-effective, the control diaphragm is preferably round over its surface and the inner rolled fold is preferably arranged concentrically to the central axis of the control diaphragm.

A further embodiment of the pressure control valve provides that the control spring on the control diaphragm initiates the spring force in an annular region which surrounds the membrane region cooperating with the larger outflow opening, while the membrane region interacting with the at least one smaller outflow opening lies outside this annular region. The introduction of the spring force in the control diaphragm thus takes place here in a membrane part which is located between the cooperating with the different outflow membrane areas. Thus, the spring force of the control spring reaches the various membrane areas on short, comparably long paths.

In an alternative embodiment, it is provided that the control spring introduces its spring force on the control diaphragm in an annular region which encloses both the membrane region cooperating with the larger outflow opening and the membrane region cooperating with the at least one smaller outflow opening. In this embodiment, the paths over which the spring force of the control spring reaches the membrane regions interacting with the various outflow openings are for a long time; These different lengths of way can be used specifically to let the single control spring act to varying degrees on the different membrane areas.

The control spring of the pressure control valve according to the invention is preferably a helical spring. In this form, the control spring is a cost-effective and reliable component that can be manufactured with low tolerances at low production costs. In addition, the coil spring offers the possibility to initiate the spring force, as described above, in an annular region in the control diaphragm, without additional measures, which is advantageous for a symmetrical loading of the control diaphragm.

Next, the invention proposes that the control diaphragm has at least one membrane support body which is arranged radially outwardly of the inner rolled fold in or on the control diaphragm. With the support body, the control membrane can be reinforced and stiffened in desired areas, in order to specifically influence the properties and the function of the control membrane and to achieve a long durability for the purpose of the longest possible trouble - free operation. At the same time the active surface of the control diaphragm is maximized by the support body, so that despite small dimensions of the pressure control valve, a good characteristic curve is achieved. The membrane support body can be arranged as a separate component between the control spring and the control diaphragm and thereby preferably linked to the control diaphragm or alternatively be integrally connected by injection molding with the control diaphragm and integrated into it. To make the control membrane as a whole easily adjustable and at the same time as easy to install in the housing of the pressure control valve is further preferred that the control diaphragm near its outer region has an outer rolled fold and with an outer edge of the membrane clamped between two interconnected parts the valve housing is held. Since the control diaphragm is usually made of an elastomer or rubber material, clamping also simultaneously achieves the desired sealing without the use of special seals. In this embodiment, the membrane support body mentioned in the preceding paragraph is preferably arranged radially between the inner and outer roll creases. Instead of the rolled fold, equivalent means may be provided in the membrane to achieve the same function, for example, as mentioned above in connection with the inner roll fold areas of different hardness, which can be generated with two-component material, or material dilutions for targeted local increase the flexibility of the membrane or a bellows.

Next is provided for the pressure control valve, that the larger outflow opening and the at least one smaller outflow opening open into a common outlet of the pressure control valve. In this way, it is achieved that the pressure control valve can be connected to the internal combustion engine via only two lines, namely an inlet leading to the inlet and a line leading away from the outlet. Alternatively, it is also possible to connect the larger outflow opening on the one hand and the at least one smaller outflow opening on the other via a separate outlet and further separate lines with different points of the internal combustion engine, in particular different sections of the intake tract. if this is advantageous or necessary for the function.

Alternatively, the larger outflow opening and the at least one smaller outflow opening may each open into a separate outlet of the pressure regulating valve. This embodiment may serve to apply the crankcase ventilation gas flowing out of the pressure control valve to two different portions of the intake tract of the associated internal combustion engine, e.g. in front of and behind a throttle or in front of and behind a turbocharger.

A development of the embodiment described above provides that in each outlet a check valve is arranged. This will produce an automatic, e.g. achieved by the pressure in each section of the intake tract dependent opening and closing of the two outlets.

Thus, the control diaphragm occupies a defined basic position in the absence of pressure difference within the pressure control valve, a stop is expediently provided in the valve housing and / or on the control diaphragm, which limits the path of movement of the control diaphragm in the opening direction. This ensures that the control diaphragm has a certain distance from the outflow openings in its basic position.

A further advantageous embodiment of the pressure control valve is that preferably a stop is provided within the control diaphragm, which is a leading movement of the cooperating with the larger outflow diaphragm portion of the control diaphragm in the closing direction relative to the cooperating with the at least one smaller discharge opening membrane region of the control diaphragm prohibited or limited. Hereby becomes prevents unwanted premature closing of the larger outflow opening by "sucking" the cooperating with the larger outflow membrane area. On the contrary, the diaphragm region of the control diaphragm which cooperates with the larger outflow opening can only move in the closing direction together with the diaphragm region of the control diaphragm which interacts with the at least one smaller outflow opening. Only the membrane region cooperating with the at least one smaller outflow opening is able to move further in the closing direction, independently of the other membrane region, when the other membrane region closes the larger outflow opening and thus reaches its end position.

With regard to the abovementioned stop, it is preferably provided that this stop is formed within the setting diaphragm by a stopper disc which engages with the membrane area cooperating with the at least one smaller outflow opening on the side facing away from the outflow openings and which is arranged on the other, with the larger outflow opening. The stop disc is a simple component that can be produced inexpensively and quickly and easily connected to the control diaphragm.

In the case of high demands on the characteristic curve of the pressure regulating valve, it may be advantageous to design the smaller outflow opening (s) as a Laval nozzle (s). If there are several smaller outlet openings, the Laval nozzles can have the same or different sizes. This ensures that at pressure differences between the inflow side of the outflow opening (s) and the intake above a certain threshold, for example about 180 hPa, in the narrowest gap, a critical pressure gradient adjusts so that the pressure drop is limited to eg about 180 hPa for the throttling at the gap between the control membrane and the / the smaller discharge opening (s) even at high pressures in the intake system. As a result, greater independence of the crankcase pressure from the negative pressure in the intake tract is achieved in the described map areas. The effect of this measure on the control characteristic of the pressure control valve is comparable in the mentioned operating conditions with an increase in the effective area ratio of the control diaphragm.

As is known per se, the pressure control valve according to the invention can optionally be designed as a single unit which can be connected to an internal combustion engine or, alternatively, be integrated into a component of the internal combustion engine, for example its valve cover.

The individual parts of the pressure control valve, except the control diaphragm and the control spring, are expedient injection molded plastic parts to allow cost-effective mass production with high accuracy.

In the following embodiments of the pressure control valve according to the invention will be explained with reference to a drawing. The figures of the drawing show:

FIG. 1 shows a first pressure regulating valve in vertical section in a first operating state,

FIG. 2 shows the pressure regulating valve from FIG. 1 in the same representation in a second operating state,

FIG. 3 shows the pressure regulating valve from FIGS. 1 and 2 in the same representation in a third operating state, FIG. 4 shows an actuating diaphragm of the pressure regulating valve according to FIGS. 1 to 3 as an individual part in an enlarged vertical section,

FIG. 5 shows the pressure regulating valve from FIG. 1 in a horizontal section according to the section line V-V in FIG. 1,

6 shows the pressure control valve in a second embodiment in vertical section in an operating state which corresponds to the operating state shown in Figure 1,

Figure 7 shows the pressure control valve in a modified version in a part -Vertikalschnitt, and

FIG. 8 shows the pressure regulating valve in a further embodiment in a vertical sectional view in an operating state which corresponds to the operating state shown in FIG.

As shown in Figures 1 to 3, the pressure regulating valve 1 shown here has a housing 10 which is closed on the top side with a lid 10 '. From the left, an inlet 11 opens into the housing 10. To the right goes from the housing 10, an outlet 12. Both the inlet 11 and the outlet 12 are each formed here as a pipe socket for connecting in each case a continuing, not shown here line. The inlet 11 is usually connected to the crankcase of an associated internal combustion engine; the outlet 12 is usually connected to the intake tract of an internal combustion engine, not shown here. In the housing 10, a control membrane 2 with its membrane edge 20 is sealingly clamped and held between its upper side and the lid 10 '. The control diaphragm 2 separates an area 13 below it in the housing 10 from an upper area 14 lying between the control diaphragm 2 and the cover 10 '. The area 14 communicates with a reference pressure source via a reference pressure port 14', which in the simplest case the surrounding atmosphere can be.

Centrally below the control diaphragm 2, a first, larger discharge opening 15 is arranged, which has the shape of a pipe section, the upper end face of which forms an annular sealing surface 15 '. At the lower end of the pipe section, the discharge opening 15 is connected to the outlet 12.

To the left and right of the larger outflow opening 15 is spaced from each have a smaller discharge opening 16, also in the form of a respective pipe section arranged. The upper front end of the two smaller outflow openings 16 each forms an annular sealing surface 16 '. At the lower end, the two smaller outflow openings 16 forming pipe sections are also connected to the outlet 12.

Concentric with the larger outflow opening 15 and radially outside the two smaller outflow openings 16 designed as a helical spring control spring 3 in the region 13 of the housing 10 is arranged. The control spring 3 is supported with its lower end on the housing 10 and exerts with its upper end in an annular region 29 an acting in the opening direction spring force on the control diaphragm 2. To secure the position of the rule - spring 3 relative to the control diaphragm 2 has the latter one integrated membrane support body 24, of which integrally projecting a Federzentrierring 28 downwards, which surrounds the upper end of the control spring 3.

The control membrane 2 is seen here in plan view circular and has two concentric rolling folds 21 and 22. The roll fold 21 is arranged as an inner roll fold in a region of the control diaphragm 2, which cooperates between a membrane region 25 which cooperates with the larger outflow opening 15 and a membrane region 26, which cooperates with the two smaller outflow openings 16, is arranged. The second roll fold 22 is arranged as an outer rolled fold directly radially inward from the clamping edge 20 of the control membrane 2.

On its side facing away from the outflow openings 15, 16, the control diaphragm 2 has a central, undercut projection 23 'on which a stop disc 23 is latched. The stop disc 23 extends in the radial direction outwardly beyond the inner roll fold 21 away into a region above the membrane portion 26, which cooperates with the smaller outflow openings 16.

By stops 27, which are arranged at the top of the control diaphragm 2 in its radially outer part directly radially inward of the outer roll fold 22, a defined, shown in Figure 1 position of the control diaphragm 2 is effected in its open position. In this position, the stops 27 on the underside of the lid 10 'are formed on it, downwardly facing projections.

The operating state shown in FIG. 1, in which the control diaphragm 2 is in its upper end position. finds, takes the pressure control valve 1, if there is no pressure difference, ie in particular at standstill of the associated internal combustion engine. In this state, the control spring 3 ensures that the control diaphragm is moved up to the start of the attacks 27 against the lid 10 'upwards or held in this position.

FIG. 2 shows a second operating state of the pressure regulating valve 1, which occurs when the pressure in the crankcase of the internal combustion engine drops. This sinking pressure propagates through the inlet 11 into the region 13 below the control diaphragm 2 of the pressure control valve 1 and causes a force acting on the control diaphragm 2 pressure difference and thus an adjusting force. The pressure difference moves counter to the force of the control spring 3, the control diaphragm 2 in total in the closing direction until, as shown in Figure 2, the central diaphragm region 25 comes into contact with the sealing seat 15 'of the larger outlet opening 15.

In addition to the sealing seat 15 'are the sealing seats 16' of the two smaller outflow openings 16 seen in the closing direction of the control diaphragm 2 behind the sealing seat 15 'back, so that in the state shown in Figure 2, the membrane regions 26 which cooperate with the two smaller outflow openings 16, still have distance from the associated sealing seats 16 'of the smaller outlet openings 16. In this state, the crankcase ventilation gas to be discharged from the crankcase flows only through the two smaller outflow openings 16, which have a free cross section, which in total is significantly smaller than the cross section of the larger outflow opening 15; This results in a favorable ratio of the surface of the control diaphragm 2 to the cross-sectional area of the two smaller outflow openings 16 with high control quality. Because of the Flexibility of the inner region 21, which is arranged around the membrane region 25 cooperating with the outflow opening 15, is reduced only slightly when the positioning membrane 2 is placed on the sealing seat 15 ', the membrane active area and thus the remaining membrane force. Here, therefore, the pressure control in the crankcase is effected only by the two smaller outflow openings 16 and the membrane region 26 cooperating therewith.

FIG. 3 shows the pressure regulating valve 1 from FIGS. 1 and 2 now in a third operating state in which the two smaller outflow openings 16 are now closed after the larger outflow opening 15. This condition occurs when the pressure in the crankcase of the internal combustion engine drops so far that the pressure difference caused thereby now also the so far downwardly cooperating with the smaller outlet openings membrane region 26 of the control diaphragm 2 against the force of the same control spring 3, until the membrane region 26 comes into sealing contact with the sealing seats 16 'of the two smaller outflow openings 16. In this state, no crankcase ventilation gas can flow through the pressure control valve 1, whereby the pressure in the crankcase increases again until the pressure difference thereby changed again to an adjustment first of the outer membrane part 26 and, with further increasing pressure, and the inner membrane part 25 in the opening direction, up here, leads.

Figure 4 shows an enlarged view of the control diaphragm 2 in cross section as a single part. Right outside, ie in Figure 4 left and right, the radially outer edge of the membrane 20 is visible, which serves for sealing clamping of the control diaphragm 2 between the housing and its lid. Radially inward on the edge 20 follows the outer Roll fold 22, which serves to adjust the control diaphragm 2 in total.

Radially further inward, the membrane support body 24, which is embedded in the remaining membrane 2 follows. The control diaphragm 2 has upwardly projecting ribs, which form the stop 27 for the movement of the control diaphragm 2 in the opening direction, ie upwards. Projecting downwardly, the membrane support body 24 has the one-piece spring centering ring 28.

Radially further inward, the inner rolled fold 21 then follows, separating the central membrane region 25 from the membrane region 26 which projects radially outwards onto the roll fold 21.

On the upper side, the control diaphragm 2 has the central, undercut projection 23 ', on which the stop disc 23 is latched. The stop disc 23 protrudes in the radial direction outward beyond the inner roll fold 21 over the membrane region 26. As FIG. 4 illustrates, the underside of the stop disc 23 forms in its radially outer region a stop 27 'for the upper side 26' of the membrane region 26 It is thereby achieved that the central diaphragm region 25 can not advance in the axial direction downwards relative to the diaphragm region 26 lying radially outwardly therefrom. Rather, the central membrane region 26 can only be moved downwards in this direction together with the membrane region 26 located radially outside the inner roll fold. Conversely, however, there is the freedom that the diaphragm region 26 lying radially outward of the inner rolled fold 21 moves downwards in the axial direction relative to the radially inner diaphragm region 25, as has already been described in connection with FIG. Radially inside of Federzentrierring 28 is an annular portion 29 of the control diaphragm 2, in which the control spring not shown here rests with its upper end and exerts its upward spring force on the control diaphragm 2.

Figure 5 shows the pressure control valve according to Figures 1 to 3 in a longitudinal section along the section line V-V in Figure 1. Particularly clearly shows the figure 5 that the housing 10 is round and that accordingly also not visible here control diaphragm has a matching round outline.

On the left in FIG. 5, the inlet 11 for the crankcase ventilation gas can be seen; to the right, the outlet 12 goes off.

In the center of the housing 10 is in the housing portion 13, ie below the not visible here Stellmembran, the larger outflow opening 15 with her here the viewer facing sealing surface 15 '.

Left and right of the central larger outflow opening 15, the two smaller outflow openings 16 are arranged eccentrically and at a distance, in which case each of their sealing surface 16 'faces the viewer.

FIG. 6 shows a modified embodiment of the pressure regulating valve 1, which differs essentially from the previously described embodiment in that the example according to FIG. 6 dispenses with a stop disc in the control diaphragm 2. The central part of the control membrane 2 forms here the membrane region 25, which cooperates with the central, larger outflow opening 15. Ra This is followed by the inner rolled fold 21, which in turn is followed further radially outwardly by the membrane region 26, which cooperates with the two smaller outflow openings 16. Radially outermost here is the control diaphragm 2 by means of its membrane edge 20 sealingly between the housing 10 and the lid 10 'is held. In the interior of the housing 10, the radial outer fold 22 lies directly radially inward of the clamping edge 20. Between the radially outer roll fold 22 and the radially inner roll fold 21, the membrane support body 24 is braced in the control membrane 2 and stiffens this part of the membrane 2. Again, the control diaphragm 2 carries upwardly projecting ribs, which form the stop 27 for limiting the movement of the control diaphragm 2 in the opening direction. On the underside, here too the membrane support body 24 has the spring centering ring 28. Radially inwardly of this Federzentrierring 28 which also here the shape of a coil spring having control spring 3 is located at its upper end to the annular portion 29 of the control diaphragm 2 and exerts its spring force in the opening direction, ie upwards, on the control diaphragm 2.

The operating state of the pressure regulating valve 1 shown in FIG. 6 is established when there is no pressure difference at the adjusting diaphragm 2. In this state, the control spring 3 pushes the control membrane 2 in the opening direction upwards until it rests with its stop 27 on the underside of the lid 10 '.

With decreasing pressure in the crankcase of the associated internal combustion engine, ie with decreasing pressure in the inlet 11 and in the housing portion 13, the control diaphragm 2 moves downwards due to the pressure difference applied thereto, whereby also here, as already described in FIG. First, the central membrane area 25, the larger outlet opening 15 is reduced and finally closes. As the pressure in the crankcase continues to fall, the diaphragm region 26 lying radially outward moves even further down until it initially reduces the size of the two smaller outflow openings 16 and finally completely closes them. The functions of the pressure control valve 1 according to Figure 6 thus correspond to the functions of the pressure control valve, which has been shown and explained in Figures 1 to 3. The other visible in Figure 6 items correspond to the items in accordance with the above-described drawings with the same reference numerals.

FIG. 7 shows in a partial vertical section a section of a pressure regulating valve 1 in a further embodiment. Characteristic of this embodiment is that the two smaller outflow openings 16 are each here in the form of a Laval nozzle. The cross section of the two smaller outflow openings 16 is initially seen relatively small in the flow direction, and then becomes slower again after a smallest diameter. The execution of the smaller outflow openings 16 as Laval nozzles offers the advantage that at pressure differences between the inflow side of the outflow openings 16, here in the region 13 of the valve housing 10, and the outlet 12, which is usually connected to the intake of an associated internal combustion engine, above a certain Limit value, in practice, for example, about 180 hPa, at the narrowest point of the discharge openings 16 sets a so-called critical pressure gradient. Thus, for the throttling at the gap between the control diaphragm and the smaller outflow openings 16, the pressure drop to the abovementioned limit value even at a high negative pressure in the outlet 12. value, for example, limited to 180 hPa. In this way, a greater independence of the crankcase pressure from the negative pressure in the outlet 12 is achieved.

FIG. 8 shows, in the same representation as FIG. 1, a further embodiment of the pressure regulating valve 1. In most parts, the pressure regulating valve 1 coincides with the pressure regulating valve 1 according to FIGS. 1 to 3.

Unlike the previously described examples, in the pressure control valve 1 according to FIG. 8, the larger outflow opening 15 opens into a first outlet 12 and the two smaller outflow openings 16 open together into a second outlet 12 'which is fluidly separated from the first outlet 12 is. Thereby, it is possible to supply the partial flow of the crankcase ventilation gas, which flows through the outlet 12, to another region of the intake tract of an associated internal combustion engine than the partial flow of the crankcase ventilation gas, which flows through the other outlet 12 '.

In addition, each outlet 12, 12 'is assigned its own non-return valve 17, 17'. The check valves 17, 17 'adjust automatically depending on the pressure conditions on the two sides of the check valve 17 and 17', so that depending on the existing pressure conditions automatic opening and closing of the outlet 12 and the outlet 12 'is effected.

Claims

Claims:

1. Pneumatic pressure control valve (1) for automatic control of the pressure in the crankcase of an internal combustion engine, wherein the pressure control valve (1) is arranged in the course of a crankcase ventilation line whose passage by means of the pressure control - valve (1) in dependence on the differential pressure between a reference pressure and an an inlet (11) of the pressure control valve (1) adjoining gas pressure is automatically changed, wherein in the pressure control valve (1) in a valve housing (10) clamped control diaphragm (2) is provided, on the one hand by the reference pressure and on the other hand by the gas pressure and by spring force is applied, whereby when changing the differential pressure between the diaphragm (2) adjacent areas (13, 14), the control diaphragm (2) is adjusted and the control diaphragm (2) the passage through a first, larger outflow opening (15) and at least a separate, spaced second, smaller, parallel durc hströmbare outflow opening (16) of the pressure control valve (1) increases or decreases, wherein at decreasing pressure at the inlet (11) of the pressure control valve (1) by the control diaphragm (2) first the larger outflow opening (15) and only then the smaller outflow opening (16) is closable, characterized - That the control diaphragm (2) is acted upon by a single acting in the opening direction control spring (3) for generating the spring force,

- That by the single control spring (3), the spring force can be introduced both into one with the larger outflow opening (15) cooperating membrane area (25) and in one with the at least one smaller discharge opening (16) cooperating membrane area (26)

- That the membrane region (25) which cooperates with the larger outflow opening (15), relative to the rest of the control diaphragm (2) is adjustable perpendicular to the diaphragm plane and has a surface which is at most 1/5 of the total area of the control diaphragm

(2)

- That the control diaphragm (2) around the with the larger outflow opening (15) cooperating membrane area (25) around an inner rolled fold (21) and

- That with the at least one smaller discharge opening (16) cooperating membrane region (26) of the control diaphragm (29) outside the inner

Roll fold (21) is located.

2. Pressure control valve according to claim 1, characterized in that the membrane region (25) which cooperates with the larger outflow opening (15) has an area which is at most 1/8 of the total area of the control diaphragm (2).

3. Pressure control valve according to claim 1 or 2, characterized in that seen in section parallel to the control diaphragm (2), the valve housing is round.

4. Pressure control valve according to one of claims 1 to 3, characterized in that the larger outflow opening (15) centrally in the valve housing (10) and the smaller outflow opening (16) is arranged eccentrically in the valve housing (10).

5. Pressure control valve according to one of claims 1 to 3, characterized in that the larger outflow opening (15) is arranged centrally in the valve housing (10) and that in addition to the larger outflow opening (15) symmetrically to and radially outside of this two or more smaller outflow openings (16) are provided.

6. Pressure control valve according to claim 5, characterized in that the cross-sectional area of the larger outflow opening (15) is greater than the cross-sectional area sum of the two or more smaller outflow openings (16).

7. Pressure control valve according to one of the preceding claims, characterized in that the at least one smaller outflow opening (16) cooperating with the control diaphragm (2) sealing surface (16 '), in the closing movement direction of the control - membrane (2) seen behind a likewise with the control diaphragm (2) cooperating sealing surface (15 ') of the larger outflow opening (15) lies back.

8. Pressure control valve according to claim 7, characterized in that the sealing surface (16 ') of the at least one smaller outflow opening (16) by 0.2 to 1.0 mm, preferably by 0.3 to 0.6 mm, behind the sealing surface ( 15 ') of the larger outflow opening (15) is behind.

9. Pressure control valve according to one of the preceding claims, characterized in that the control diaphragm (2) seen over its surface is round and that the inner roll fold (21) is arranged concentrically to the central axis of the control diaphragm (2).

10. Pressure control valve according to one of claims 1 to 9, characterized in that the control spring (3) on the control diaphragm (2) introduces the spring force in an annular region (29), which cooperates with the larger outflow opening (15) membrane region (25 ), while the membrane region (26) cooperating with the at least one smaller outflow opening (16) lies outside this annular region (29).

11. Pressure control valve according to one of claims 1 to 9, characterized in that the control spring (3) on the control diaphragm (2) introduces the spring force in an annular region (29), both the with the larger outflow opening (15) cooperating membrane area ( 25) and the membrane region (26) cooperating with the at least one smaller outflow opening (16).

12. Pressure control valve according to one of the preceding claims, characterized in that the control spring (3) is a helical spring.

13. Pressure control valve according to one of the preceding claims, characterized in that the control diaphragm (2) has at least one membrane support body (24) which is arranged radially outwardly of the inner rolled fold (21) in or on the control diaphragm (2).

14. Pressure control valve according to one of the preceding claims, characterized in that the control diaphragm (2) near its outer region an outer rolled fold (22) and with an outer diaphragm edge (20) is clamped between two interconnected parts of the valve housing (10) ,

15. Pressure control valve according to one of claims 1 to 14, characterized in that the larger outflow opening (15) and the at least one smaller outflow opening (16) in a common outlet (12) of the pressure control valve (1) open.

16. Pressure control valve according to one of claims 1 to 14, characterized in that the larger outflow opening (15) and the at least one smaller outflow opening (16) each in its own outlet (12, 12 ') of the pressure control valve (1) open.

17. Pressure control valve according to claim 16, characterized in that in each outlet (12, 12 ') a check valve (17, 17') is arranged.

18. Pressure control valve according to one of the preceding claims, characterized in that in the valve housing (10) and / or on the control diaphragm (2), a stop (27) is provided which limits the path of movement of the control diaphragm (2) in the opening direction.

19. Pressure control valve according to one of the preceding claims, characterized in that within the control diaphragm (2) a stop (27 ') is provided, which is a leading movement of the membrane with the larger outflow opening (15) cooperating Rich (25) of the control diaphragm (2) in the closing direction relative to the cooperating with the at least one smaller discharge opening (16) membrane region (26) of the control diaphragm (2) prevents or limits.

20. Pressure control valve according to claim 19, characterized in that the stop (27 ') within the control diaphragm (2) by a with the at least one smaller outflow opening (16) cooperating membrane region (26) at the outflow openings

(15, 16) on the opposite side, at the other, with the larger discharge opening (15) cooperating membrane region (25) arranged stop disc (23) is formed.

21. Pressure control valve according to one of the preceding claims, characterized in that the smaller (n) outflow opening (s) (16) is designed as a Laval nozzle (s) is / are.