Patent Publication Number: US-10787942-B2

Title: Valve component for regulating or controlling a fluid pressure

Description:
BACKGROUND OF THE INVENTION 
     The invention concerns a valve component for regulating or controlling a fluid pressure, in particular for the pressure regulation of the internal combustion engine and/or of the crankcase of the internal combustion engine of a motor vehicle. 
     Pressure regulating valves are employed, for example, in the venting line between crankcase and the intake manifold of an internal combustion engine. In this context, the goal is to prevent the pressure or vacuum in the containers to be vented from rising beyond a predetermined value. 
     In internal combustion engines, blow-by gases occur that are produced in that the combustion gases in the cylinder escape past the cylinder piston into the crankcase. These blow-by gases cause the pressure in the crankcase to rise, and leakages and escape of oil may be the result. In order to avoid a pressure increase and to discharge the blow-by gases in an environmentally friendly way, the blow-by gases are returned from the crankcase into the air intake manifold of the internal combustion engine. On the other hand, the specified vacuum value should not be undershot significantly because then, due to leaks, undesirable leak air would be sucked into the crankcase. 
     In case of the pressure regulating valves that are currently employed, usually a switching film, known to a person of skill in the art also by the term “switching diaphragm”, made of elastomer, frequently fluorosilicone rubber (FVMQ), is used. These switching films are very flexible due to the specific properties of elastomers. As a function of the applied pressure conditions, this switching film opens and closes an opening in the pressure regulating valve. The pressure ratio results usually from the pressure difference between the applied pressure in a first chamber and the existing pressure in a second chamber of the pressure regulating valve. The pressure in the first chamber can be the same as atmospheric pressure, for example. The switching film must react to minimal switching pressures in the magnitude of 1 mbar to 250 mbar. The pressure regulating valve regulates the flow by the pressure difference applied to the switching film without additional control member such as, for example, an actuator or the like. 
     Blow-by gases are comprised of uncombusted fuel proportions, engine oil proportions, and other contaminants produced by combustion. These gases attack many elastomer types whereby damages of the material properties may occur. The components made of these materials become brittle, porous, and cracked. When the switching films are damaged, the environmentally harmful blow-by gases directly reach the environment because the system is no longer seal-tight. The switching film of an elastomer is usually embodied as a rolling film in order to realize a specified stroke of the film. 
     In the known pressure regulating valves, the switching diaphragm, depending on respective operating point and employed material of the switching diaphragm, may be excited to vibrate which leads to disruptive noises that moreover may propagate into the environment through the required venting bore in the cover of the pressure regulating valve. 
     DE 101 43 686 A1 discloses a venting valve in which a channel projects into a venting line and is connected to a Helmholtz resonator. The Helmholtz resonator is matched to the frequency range of the noises to be suppressed and forms a λ/4 resonator. Acoustic measures in the form of Helmholtz resonators and the like require however additional components, installation space, and connecting parts. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a valve component for switching at low pressure differences which exhibits a low noise development when operated at an internal combustion engine. 
     The aforementioned object is solved according to an aspect of the invention by a valve component that comprises a unit for regulating or controlling a fluid pressure and further comprises an expansion chamber, wherein the unit comprises a valve housing, comprising a first housing part and a second housing part, between which a switching element is arranged, wherein the first housing part comprises an inlet and an outlet for a fluid, wherein the switching element is arranged between the inlet and the outlet for regulating, releasing or shutting off a flow of the fluid, wherein the switching element separates two chambers in the housing from each other, wherein, in open switching position of the switching element, inlet and outlet are connectable by means of one of the chambers, and wherein at least a first venting bore of the other one of the chambers opens into the expansion chamber. The expansion chamber comprises the same pressure as the other chamber connected with the expansion chamber and serves for noise minimization, wherein the expansion chamber does not affect the pressure difference at the switching element. 
     Beneficial configurations and advantages of the invention result from the additional claims, the description, and the drawing. 
     A valve component is proposed that comprises a unit for regulating or controlling a fluid pressure and further comprises at least one expansion chamber, wherein the unit comprises a valve housing, comprising a first housing part and a second housing part between which a switching element is arranged, wherein the first housing part comprises an inlet and an outlet for a fluid, wherein the switching element for regulating, releasing or shutting off a flow of the fluid is arranged between the inlet and the outlet, wherein the switching element separates two chambers in the housing from each other, wherein, in open switching position of the switching element, inlet and outlet are connectable by one of chambers, and wherein at least a first venting bore opens from the other one of the chambers into the expansion chamber. 
     Advantageously, a valve component, for example, a pressure regulating valve, with a damper, integrated in series, can be created for an acoustic improvement of the valve component. The expansion chamber can be formed by a single hollow space or it can be divided into several chambers; the latter can comprise the same size or can be of different size. The expansion chamber can be additionally filled with a suitable acoustically effective medium, for example, with an acoustic foam or the like. 
     The acoustic effect of the proposed valve component is determined by the volumes of the chambers and the free cross sections of the connection between the chambers and the free cross section of the venting bore into the environment. 
     By integration of an expansion chamber, arranged in series, as an acoustic damper, integrated into the valve housing and/or arranged at the valve housing of the valve component, the required installation space can be reduced compared to a solution in which one or several additional components are required. 
     In a further advantageous embodiment, as an alternative or in addition to expansion chambers provided integrated in series, the expansion chambers can also be arranged in parallel. Also, further resonator solutions can be embodied in parallel, such as broadband dampers, Helmholtz resonators or lambda-fourth tubes (λ/4 tubes). 
     Different realizations of an expansion chamber are possible. They can be selected expediently depending on the respectively employed manufacturing process for the valve component. Advantageously, despite the additional expansion chamber being provided compared to a simple valve component, the additional expenditure in regard to the manufacture of the valve component can be kept minimal. 
     The second chamber of the valve component can be loadable with an atmospheric pressure. For an effective regulating behavior of the valve component, the switching element should be able to move as freely as possible, for which purpose the second chamber, which is separated by the switching element from the first chamber in which the fluid to be regulated is contained, is expediently in communication with the environmental region, i.e., the atmospheric pressure. A spring element engaging the switching element compensates in this context the atmospheric pressure so that the control behavior of the switching element can be realized in a low pressure difference range. 
     Advantageously, the switching element can be designed to be areal, in particular in the form of a switching film for switching at pressure differences of 1 mbar to 250 mbar, preferably of 1 mbar to 100 mbar. The valve component not only can release or shut off the flow, but can also regulate the flow of the fluid between the two switching states “release” or “shut-off” by a continuous change of the flow cross section as a function of the pressure difference between the inlet and the outlet of the valve component. 
     According to a beneficial first embodiment, the expansion chamber can be arranged at the second housing part. Preferably, the second housing part can be a housing cover. An arrangement at the second housing part is particularly beneficial when laser welding is used in manufacturing the valve housing. An integration of the expansion chamber in, or a connection with, the housing cover is advantageous because the welding process is not hindered by the housing cover. 
     According to a beneficial embodiment, the second housing part and a cover provided at the second housing part can enclose the expansion chamber. The cover can be connected fixedly with the second housing part, for example, welded thereto or glued thereto, or the cover can be provided with a suitable thread and screw-connected to the second housing part; a connection by means of fastening screws can be provided, or a locking connection. 
     According to a beneficial embodiment, the at least one first venting bore can extend from the second chamber through the second housing part into the expansion chamber at the second housing part. The configuration is beneficial when joining the first and second housing parts by means of laser welding. 
     According to a beneficial configuration, the valve component may comprise at least one second venting bore which is extending between the expansion chamber and an outer region of the valve component. In particular, the at least one second venting bore can extend in the second housing part and/or in the cover of the expansion chamber. It is possible to provide only one venting opening or several venting openings can be provided. 
     According to an alternative embodiment, the expansion chamber can be arranged in the first housing part. This arrangement is beneficial when hot plate welding is provided in the manufacturing method of the valve housing. 
     According to a beneficial configuration, a groove in the first housing part of the valve housing can form the expansion chamber wherein the groove is preferably arranged coaxial to the circumference of the switching element. Expediently, an already existing groove in the first housing part can be utilized, in particular a groove at the weld seam, by sufficiently enlarging it. 
     According to a beneficial embodiment, the at least one first venting bore can extend from the second housing part to the first housing part. The at least one venting bore can be produced in a simple way with regard to tools and positioned beneficially. 
     According to a beneficial embodiment, the at least one second venting bore can extend in the first housing part. Beneficially, the venting bore can extend from the groove outwardly. This can be realized beneficially with regard to installation space. 
     According to a beneficial embodiment, the second housing part and the first housing part can be connected by means of a locking connection. Alternatively, also other connecting techniques can be employed. 
     According to a beneficial embodiment, the switching element can be comprised of a fluorine and carbon comprising polymer material, in particular of fluorine and carbon comprising thermoplastic polymer material, in particular of PTFE (polytetrafluoroethylene). Preferably, the fluorine and carbon comprising polymer material can be polytetrafluoroethylene or polytetrafluoroethylene with admixtures or thermoplastically processible polytetrafluoroethylene. The fluorine and carbon comprising polymer film is chemically resistant and can switch many switching cycles of the switching element. The long-term stability of the valve component is improved. Alternatively, the switching element can be an elastomer. 
     Advantageously, the switching element can comprise a plate-shaped flat body with a bending region surrounding a central closure region, wherein, when switching the switching film, the bending region moves the closure region relative to a valve seat in axial direction toward the valve seat or away from the valve seat by a low-expansion, i.e., for practical application practically expansion-free, in particular expansion-free, bending movement. Since the switching element in this embodiment can bend not only within a small areal region but across a large surface area due to the plate-shape configuration, individual regions of the switching element are little loaded by expansion. The bending movement is thus carried out across a large region of the switching element and therefore with minimal elastic deformation in the form of a curvature change with minimal expansion, for example, less than 10%. 
     A fluorine and carbon comprising polymer material such as PTFE can be produced by a sintering process and subsequently mechanically processed. The film of such a material is very stiff in its normal shape and not suitable for flexible components. PTFE comprises an excellent chemical resistance and can be used within a very broad temperature range, wherein the modulus of elasticity toward low temperatures increases very strongly in comparison to elastomer materials. For this reason, PTFE is rather unsuitable for use as a film in the temperature range (−40° C. to +150° C.) required in case of automotive applications at an internal combustion machine. This disadvantage for a proposed valve component can be advantageously circumvented by a special geometry and optionally by extremely thin wall thicknesses of the film of fluorine and carbon comprising polymer. By a reduction of the wall thickness of the PTFE material in a movable region to a few tenths of a millimeter, wherein the non-movable sealing region as well as the clamping region of the material can also be embodied thicker, and by a specially developed geometry of the film without rolling region, as it is employed usually in the prior art, the stiff material can be brought into a shape in which it comprises the required flexibility but still fulfills the mechanical requirements with regard to crack formation, expansion, and bending fatigue strength. Due to the special geometry, no rolling movement occurs anymore but a low-expansion bending movement with a radius change by means of which a stroke movement of the switching element for a unit can be realized. 
     When using such a switching element in a valve component, the proposed embodiment with expansion chamber is particularly advantageous because a propagation of a possible noise can be inhibited particularly effectively. 
     In this context, by means of a spring element which is supported at the valve housing, a force is exerted on the switching element in order to be able to adjust the regulating behavior of the valve component in a suitable way. The outlet of the valve housing comprises a valve seat at an end arranged in the valve housing which is closable by the closure region of the switching element so that a conduction of the fluid from the inlet to the outlet can be regulated. 
     Optionally, the embodiments can be combined so that both housing parts have expansion chambers. 
     According to a further aspect of the invention, the use of a valve component according to the invention is proposed for pressure regulation of an internal combustion engine and/or for pressure regulation of a crankcase of an internal combustion engine. 
     In an advantageous arrangement, a cylinder head cover of an internal combustion engine comprises a valve component according to the invention for pressure regulation of a crankcase of the internal combustion engine. The valve component according to the invention is advantageously integrated into the cylinder head cover. In a particularly advantageous embodiment, the housing of the valve component is embodied as a single piece together with the housing of the cylinder head cover, in particular as an injection molded synthetic material part, in particular of thermoplastic synthetic material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, the description, and the claims contain numerous features in combination. A person of skill in the art will expediently consider the features also individually and combine them to meaningful additional combinations. 
         FIG. 1  shows a valve component with an areal switching element according to an embodiment of the invention in a section illustration. 
         FIG. 2  shows a valve component with an areal switching element according to a further embodiment of the invention in a section illustration. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the Figures, same or same-type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting. 
       FIG. 1  shows a section illustration of a first embodiment of a valve component  100  according to the invention. This embodiment is beneficial when housing parts  14 ,  16  of the valve component  100  are connected to each other by laser welding. The valve component  100  comprises a unit  10  for regulating or controlling a fluid pressure as well as at least one expansion chamber  42 . The unit  10  comprises a valve housing  12  which comprises a first housing part  14  and a second housing part  16 . The first housing part  14  comprises an inlet  22 , which is embodied like a socket in an exemplary fashion, and an outlet  24 , which is embodied like a socket in an exemplary fashion, for a fluid. Between the two housing parts  14 ,  16 , an areal switching element  50  is arranged which is serving for regulating, releasing or shutting off a flow of the fluid between the inlet  22  and the outlet  24 . The switching element  50  separates the two chambers  36 ,  38  in the housing  12  from each other, wherein, in open switching position of the switching element  50 , the inlet  20  and the outlet  24  are connectable through the bottom chamber  36 . 
     The areal switching element  50  is in particular configured as a profiled film element and can be moved without switching plunger provided at the closure region  54 . The switching element  50  comprises a flat clamping region  60  with which it is clamped between the rims of the first and second housing parts  14 ,  16 . Centrally, a closure region  54  is provided which is arranged in a depression  52 , pointing in the direction of the outlet channel toward the outlet  24  of the fluid. Substantially radially outside of the clamping region  60  of the switching element  50 , a weld groove  48  is arranged in the first housing part  14 . 
     Between the first chamber  36  and the second chamber  38 , there is a pressure difference, wherein the second chamber  38  is in communication (not illustrated) with the surroundings, i.e., the atmospheric pressure. The switching element  50  can be moved with pressure differences of 1 mbar to 250 mbar, preferably of 1 mbar to 100 mbar, and serves for releasing or shutting off a flow of the fluid between the inlet  22  and the outlet  24 . The inlet  22  of the unit  10  in the situation of use is in fluidic communication, for example, with the crankcase of an internal combustion engine while the outlet  24  is in fluidic communication with the intake manifold. The switching element  50  comprises a plate-shaped flat body with a corrugated bending region  56  surrounding the central closure region  54 . When switching the switching element  50 , the bending region  56  moves the closure region  54  relative to a valve seat  30  in axial direction L toward the valve seat  30  or away from the valve seat  30  by a low-expansion, in particular expansion-free, bending movement. The switching element  50  comprises for this purpose at least in the bending region  56  a thickness of at most 0.5 mm, preferably of at most 0.3 mm, particularly preferred of at most 0.2 mm. The diameter of the switching element  50  in this context is between 40 mm and 100 mm, preferably between 50 mm and 80 mm. 
     The bending region  56  extends in radial direction in a corrugated shape about the closure region  54  wherein a depression on a flat side corresponds to a projection at the other flat side of the switching element  50 . The closure region  54  closes off the valve seat  30  fluid-tightly when it is resting against the valve seat  30 . A spring element  34  is provided which is supported at the valve housing  12  and exerts a force on the closure region  54  of the switching element  50  and in this way compensates the atmospheric pressure in the upper second chamber  38 . The spring element  34  in this context is supported by a ring  32  at the closure region  54 . 
     The switching element  50  is preferably formed of fluorine and carbon comprising polymer film, for example PTFE. A beneficial diameter  64  of the switching element  50  is between 40 mm and 100 mm, preferably between 50 mm and 80 mm. 
     In the open state, as illustrated, the spring element  34  supported at the bottom housing part  14  of the housing  12  pushes the closure region  54  of the switching element  50  against the bottom side of the second housing part  16 . In the closed position of the switching element  50 , the spring element  34  is in a lower position in the Figure so that the switching element  50  with its closure region  54  is seated seal-tightly on the valve seat  30 . 
     At least one first venting bore  40  extends from the upper chamber  38  into the expansion chamber  42  wherein the venting bore  40  is arranged in the second housing part  16 , for example, in the housing cover. The expansion chamber  42  is arranged at the second housing part  16 . The expansion chamber  42  can be comprised of several hollow spaces or formed by one hollow space. Optionally, the expansion chamber  42  can be filled with material in order to further improve possibly its acoustic effect. 
     In the illustrated embodiment, the second housing part  16  and a cover  20  provided at the second housing part  16  enclose the expansion chamber  42 . For the aforementioned diameters of the switching element  50 , a beneficial volume of the expansion chamber  40  amounts to between 10 ml and 100 ml. The cover  20  can be welded or glued to the second housing part  16  or can be connected by means of a screw connection, locking connection or the like. 
     The first venting bore  40  extends from the second chamber  38  through the second housing part  16  into the expansion chamber  42  at the second housing part  16 . In the expansion chamber  42  at least one second venting bore  44  is arranged which is extending between the expansion chamber  42  and an outer region of the unit  10 . The second venting bore  44  extends in the second housing part  16 . Alternatively or additionally, a second venting bore  44  can be provided in the cover  20 . 
       FIG. 2  shows a section illustration of an alternative embodiment of a valve component  100  according to the invention in which the at least one expansion chamber  42  is arranged in the first housing part  14 . This embodiment is beneficial when housing parts  14 ,  16  are connected to each other, for example, by means of hot plate welding. The basic configuration of the valve component  100  matches substantially that of the embodiment in  FIG. 1 , in particular with regard to switching element  50 , chambers  36 ,  38 , inlet  22 , outlet  24 , housing parts  14 ,  16  of the housing  12 , so that for avoiding unnecessary repetitions reference is being had to the figure description of  FIG. 1 . 
     The expansion chamber  42  in the embodiment of  FIG. 2  is formed in a groove  48  in the housing  12  wherein the groove  48  is preferably arranged coaxially to the circumference of the switching element  50 . The groove  48  is in particular a weld groove which receives material when welding the two housing parts  14 ,  16  together. In order to be able to receive the expansion chamber  42 , the weld groove  48  is of a correspondingly larger embodiment. 
     At least one first venting bore  40  extends from the second housing part  16  to the first housing part  14 , wherein air from the second chamber  38  can be guided into the groove  48  provided with the expansion chamber  42 . The at least one second venting bore  40  extends in the first housing part  14  and penetrates the outer circumference of the weld groove  48 . 
     Optionally, the embodiments of  FIGS. 1 and 2  can also be present in combination. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.