ELASTOMER COMPONENT EXPOSED TO BLOW-BY GASES OF AN INTERNAL COMBUSTION ENGINE

Abstract

An elastomer component, which is exposed to blow-by gases of an internal combustion engine, includes a function body made of a elastomer material and a fluorine layer arranged on the outside of the function body.

Claims

1. An elastomer component comprising: a function body made of an elastomer material; and a fluorine layer arranged on the outside of the function body; wherein the elastomer component is exposed to blow-by gases by an internal combustion engine.

2. The elastomer component according to claim 1, wherein the function body is formed by a first elastomer and the fluorine layer is formed by a second elastomer, further wherein the first elastomer differs from the second elastomer in that it comprises adsorbed fluorine.

3. The elastomer component according to claim 1, wherein the fluorine layer and the function body are formed from the same elastomer material, further wherein the fluorine layer is formed by adsorption of fluorine in the elastomer material through fluorination of the surface of the function body with introduced elastomer material, further wherein absorption of fluorine atoms at the polymer chains of the elastomer material is by introduction of fluorine on the surface of the function body.

4. The elastomer component according to claim 3, wherein the elastomer material of the fluorine layer or the function body comprises a siloxane.

5. The elastomer component according to claim 3, wherein the elastomer material of the fluorine layer or the function body comprises a methyl vinyl silicone rubber with fluorine-containing groups.

6. The elastomer component according to claim 3, wherein the elastomer material of the fluorine layer or the function body comprises a tensile strength of 1 to 20 N/mm.sup.2.

7. The elastomer component according to claim 3, wherein the elastomer material of the fluorine layer or the function body comprises an average density of 1.4 to 1.7 g/cm.sup.3.

8. The elastomer component according to claim 3, wherein the elastomer material of the fluorine layer or the function body comprises a Shore A hardness of 35 to 90.

9. The elastomer component according to claim 1, wherein at least one side of the function body facing a blow-by gas comprises the fluorine layer, and the function body is completely enclosed by the fluorine layer.

10. The elastomer component according to claim 1, wherein the fluorine layer has an average layer thickness or fluorine penetration depth of 0.01 to 20 m.

11. The elastomer component according to claim 1, wherein the fluorine layer has a first fluorine content and the function body has a second fluorine content, wherein the first fluorine content is larger than the second fluorine content.

12. The elastomer component according to claim 1, wherein the elastomer component comprises at least one cantilever or undercut.

13. The elastomer component according to claim 1, wherein the elastomer component comprises a valve member of a control valve, a non-return valve, a valve, a venting valve, a pressure relief valve or a diaphragm-shaped actuator, and comprises pressure control valves, or a seal, including a piston seal, shaft seal, housing seal, valve seal, or line seal.

14. The elastomer component according to claim 1 available by fluorination, wherein the elastomer component is formed by: introducing an elastomer substrate into a process chamber; evacuating of the process chamber; supplying of a first gas composition comprising elemental fluorine gas, such that the process chamber comprises elemental fluorine gas at a process chamber concentration; tempering the elastomer substrate in the process chamber for a tempering period under conversion of the first gas composition into a second gas composition and under forming of the fluorine layer of the elastomer component by fluorinating the surface of the elastomer substrate; removing of the second gas composition comprising elemental fluorine gas and hydrogen fluoride from the process chamber; and removing of the elastomer component from the process chamber.

15. A method for producing an elastomer component exposed to blow-by gases, the method comprising: introducing an elastomer substrate into a process chamber; evacuating of the process chamber; supplying of a first gas composition comprising elemental fluorine gas, such that the process chamber comprises elemental fluorine gas at a process chamber concentration; tempering the elastomer substrate in the process chamber for a tempering period under conversion of the first gas composition into a second gas composition and under forming of the fluorine layer of the elastomer component by fluorinating the surface of the elastomer substrate; removing of the second gas composition comprising elemental fluorine gas and hydrogen fluoride from the process chamber; and removing of the elastomer component from the process chamber.

16. The method according to claim 15, wherein the first gas composition comprises elemental fluorine gas and at least one other gas selected from a group consisting of nitrogen, helium, and argon, or another inert gas.

17. The method according to claim 15, wherein the tempering is performed at 10 to 100 C., in particular 20 to 60 C., preferably at 25 to 40 C.

18. The method according to claim 15, wherein the pressure in the process chamber is less than 10.sup.2 mbar after the evacuating.

19. The method according to claim 15, further comprising: arranging a fluorine layer on the outside of a function body in a blow-by gas treating device, wherein elastomer components comprise the function body made of an elastomer material, wherein the elastomer component is exposed to blow-by gases.

20. The method according to claim 19, further comprising: increasing a chemical stability of the elastomer components to reduce the precipitation of pollutants from blow-by gases in the elastomer component to reduce the precipitation of manganese.

21. A blow-by gas treating device comprising: an elastomer component comprising: a function body made of an elastomer material; and a fluorine layer arranged on the outside of the function body; wherein the elastomer component is moveable and is exposed to at least a part of blow-by gas of an internal combustion engine.

22. The device of claim 21, wherein the blow-by gas treating device comprises an oil separator, a valve, a compressor or a turbine.

23. An elastomer component exposed to blow-by gases by an internal combustion engine, wherein the elastomer component is formed by: introducing an elastomer substrate into a process chamber; evacuating of the process chamber; supplying of a first gas composition comprising elemental fluorine gas, such that the process chamber comprises elemental fluorine gas at a process chamber concentration; tempering the elastomer substrate in the process chamber for a tempering period under conversion of the first gas composition into a second gas composition and under forming of the fluorine layer of the elastomer component by fluorinating the surface of the elastomer substrate; removing of the second gas composition comprising elemental fluorine gas and hydrogen fluoride from the process chamber; and removing of the elastomer component from the process chamber.

24. A system configured for discharge and feeding of blow-by gas of an internal combustion engine, wherein the system comprises: a blow-by gas emerging from an engine bay of the internal combustion engine that is received and at least partially circulated back into a combustion cycle of the internal combustion engine; and at least one elastomer component arranged to be exposed to at least part of the blow-by gas.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Further advantages, effects, and embodiments of this invention can be seen in the figures below.

[0041] FIG. 1 shows a schematic view of blow-by gas circuit within an internal combustion engine;

[0042] FIG. 2 shows a cross-sectional view of a blow-by gas recirculation system;

[0043] FIG. 3 shows a cross-sectional view of a non-return valve built into a blow-by gas recirculation system;

[0044] FIG. 4 shows a perspective cross-sectional view of the valve member of the non-return valve in FIG. 4;

[0045] FIG. 5 shows a cross-sectional view of a mushroom valve built into a blow-by gas recirculation system;

[0046] FIG. 6 shows a perspective cross-sectional view of the mushroom valve in FIG. 5;

[0047] FIG. 7 shows a cross-sectional view of a pressure control valve built into a blow-by gas recirculation system; and

[0048] FIG. 8 shows a perspective cross-sectional view of the actuator of the pressure control valve in FIG. 7.

DETAILED DESCRIPTION

[0049] To illustrate possible fields of application of the present embodiments, FIG. 1 shows an exemplary schematic blow-by gas circuit 1 of an internal combustion engine. It comprises a reciprocating piston engine 3, an air inlet 5 feeding the reciprocating piston engine, an exhaust 7 and a blow-by gas recirculation system 9. The reciprocating piston engine 3 comprises a cylinder 13, a piston 23 located in the cylinder, a crankcase 33 connected to the cylinder, a crank drive 43 coupled to the piston, and an oil pan 53. During the combustion process in the reciprocating piston engine 3, in particular during the compression and expansion of the fuel mixture, blow-by gases, in particular unburned fuel mixtures, engine oils and/or exhaust gases, flow between piston 23 and cylinder 13 into the crankcase 33. To reduce the blow-by gas flow flowing into the crankcase 33, piston seals (not shown), in particular sealing rings are used, which seal the combustion chamber 63 with respect to the crankcase. One field of application of the elastomer component according to the invention are seals between cylinder head 63 and cylinder 13, which are not shown, in order to prevent the escape of blow-by gases into the environment. Another conceivable field of application for the elastomer component according to the invention relates generally to the sealing of pistons or other moving parts exposed to blow-by gases.

[0050] In the blow-by gas circuit shown, the crankcase 33 is connected to the air supply 5 of the reciprocating piston engine 3 via a blow-by gas recirculation system 9. In the example shown, blow-by gases are passed from the crankcase 33 via an oil mist separator 19 to a pressure control valve 29. Therein, the gases are fed to the separator 19 via a separator feeding line 119. Separated oil is returned to the crankcase 33 via an oil return line 219. The remaining blow-by gas is fed to the pressure control valve 29 via a separator outlet line 319. Depending on the implementation of the blow-by gas circuit, seals between the separator feeding line 119, the oil return line 219, the separator outlet line 319, the oil mist separator 19, and/or the crankcase can be embodied as elastomer components according to the invention. It is clear that all the seals exposed to blow-by gases listed so far and below can be embodied as elastomer components according to the invention.

[0051] The pressure in the crankcase is adjusted via the pressure control valve 29. It has proven advantageous for pressure control valves in blow-by gas recirculation systems to use valves with pressure control diaphragms as shown in FIGS. 7 and 8, for example. It is particularly advantageous to implement the actuator, in particular the diaphragm 703, of the pressure control valve as an elastomer component in accordance with the invention. In the circuit shown, blow-by gases leaving the control valve are divided into several, in particular two, separate suction feeding lines 129, 229 via a flow splitter, in particular a T-piece. Seals between the lines and the flow splitter can be implemented as an elastomer component in accordance with the invention. The suction feeding lines 129, 229 and the air supply 5 are separated from each other in the presented blow-by gas circuit 1 by non-return valves 49, 59. It has been shown that non-return valves with seal washers 503, in particular as shown in FIGS. 3 and 4, are particularly advantageous for use in blow-by gas circuits. It has been shown to be particularly advantageous to configure the seal washers as elastomer components in accordance with the invention. The use of elastomer components according to one embodiment, in particular in the form of seal washers 503, in non-return valves 49, 59, is shown in FIG. 3, in blow-by gas circuits between suction feeding line 129, 229 and the air supply 5.

[0052] The separate suction feeding line 129, 229 supplies to different admission points of the air inlet 5. Depending on the operating condition, in particular the pressure in the crankcase and the intake pressure in the air inlet 5, the blow-by gas flow is supplied to the air inlet 5 via one or both suction feeding line 129, 229. A suction feeding line 129 supplies the blow-by gas flow to an intake flow splitter 55 between an intake air filter 15 and a compressor 25 where blow-by gas mixes with fresh air. The resulting mixture of air and blow-by gas can be supplied from the intake flow splitter 55 to the reciprocating piston engine 3 via a compressor line 125 and a ventilation system 135. In compressor line 125, the air-blow-by-gas mixture is supplied to cylinder 13 via a compressor 25, an intercooler 65 and a throttle valve 75. The air-blow-by-gas mixture can escape between the drive shaft of compressor 25, which is not shown, and the compressor housing of a turbocharger. Similarly, blow-by gases can escape between the output shaft of a turbine, especially a turbocharger, and the turbine casing. In order to reduce the escape of blow-by gas via the compressor and/or turbine, seals between the input shaft of a compressor and a compressor casing and/or between the output shaft of a turbine and a turbine casing may be implemented as elastomer components according to the invention. It is clear that the blow-by gas recirculation system 9 illustrated here can also be provided on compressor and turbine housings, in particular for turbochargers, to recirculate escaping blow-by gases. Via the ventilation system 135, the air-blow-by-gas mixture can be supplied from the flow splitter to the reciprocating piston engine via a throttle 35 and a non-return valve 45, like a mushroom valve. The second suction feeding line 229 supplies the blow-by gas flow to compressor line 125 behind the throttle cap. It is clear, that in particular all the seals and valve members and actuators of valves, and valves exposed to blow-by gases shown with reference to FIG. 1 can be implemented as elastomer components in accordance with the invention.

[0053] FIG. 2 shows a cross-sectional view of an exemplary system for the discharge and supply of blow-by gases, in particular a recirculation system 409 for blow-by gas. It comprises a recirculation system housing 411, in particular comprising a housing body 413 and a housing base 415. The blow-by gases are feed into the recirculation system via a return inlet 417 and diverted from the recirculation system via return outlets 419, 421. From the crankcase, the gas first flows through the return inlet 417, through an opening in the housing base, into a first recirculation chamber 423. From the first recirculation chamber 423, the blow-by gas flows, through an oil separator 425, into a second recirculation chamber 427. The oil separator can be implemented as a deflecting separator. In particular, a bypass valve 429 may also be provided through which the blow-by gas may flow from the first recirculation chamber 423 to the second recirculation chamber 427, e.g. at high crankcase pressure and/or clogged oil separator. A possible embodiment of a bypass valve 429 is shown in detail in FIGS. 5 and 6 as a non-return valve, in particular in the form of a mushroom valve. The blow-by gas is supplied from the second working chamber 427 via a pressure control valve 431 to a third recirculation chamber 433. One embodiment of a pressure control valve 431 in the recirculation system 409 is shown in detail in FIG. 7 and FIG. 8. From the third recirculation chamber 433 the blow-by gas is discharged from the recirculation system via non-return valves 435, 437 via the return outlets 419, 421, and supplied in particular to a suction feeding line 125. One embodiment of the non-return valve 435, 437 from FIG. 2 is shown in detail in FIG. 3 and FIG. 4. In particular, the blow-by gas in partial load operation of the engine can be diverted from the recirculation outlet via a non-return valve 435 arranged in the housing base. In full-load operation, however, the blow-by gas should be diverted from the recirculation outlet 421 in particular via a cylindrical intake socket and a non-return valve mounted therein. Valve members, such as seal washers of non-return valves, mushroom valves, and/or actuators, such as diaphragms, are implemented as elastomer components according to the invention. Furthermore, seals between the housing body and the housing base that are not shown may be implemented as elastomer components according to one embodiment.

[0054] FIG. 2 also shows an oil return socket through which separated oil is discharged from the second return chamber 427. Here, too, it is possible to use elastomer components according to the invention in the form of valve members, actuators, and/or seals. In addition, elastomer components according to the invention for seals 443 can be employed between the housing base and the crankcase or engine housing.

[0055] FIG. 3 shows an advantageous non-return valve 45, 49, 59 for use in blow-by gas circuits 1. It comprises a valve body 501 and a valve member 503, in particular in the form of a seal washer 503. A perspective cross-sectional view of the valve member is shown in FIG. 4. The valve body 501 is sealed by a sealing element 505, a sealing ring, against a housing 507, for example of a recirculation system. Such a non-return valve may, for example, be located between an air inlet 5, in particular upstream of a suction line 115, and a recirculation system housing 411, 507, in particular a return inlet 417 thereof, as shown in FIG. 2. The charging pressure of the suction line 115 is usually two bars. Due to pressure differences between the charging pressure of the suction line and the blow-by gas pressure, the valve member is pushed in the direction of the valve body so that the blow-by gas flow can flow into the valve body through openings 509 in the recirculation system housing 507. The valve member 503 may be implemented as an elastomer component according to the invention. The sealing means 505 is also designed as an elastomer component according to the invention. The valve member may be implemented as disc-shaped and has an outer diameter and a thickness. In particular, the valve member has an opening 511, in particular a circular hole. The opening may be in the center of the valve member. In particular, the size of the opening correlates with a guide pin 513 protruding from the housing. The guide pin may have a cylindrical guide surface. In particular, the valve member is mounted slidingly, especially on the guide pin. In the closed state, the valve member rests against the housing and closes the housing openings 509. In the open state, the valve member is moved away from the housing, in particular pressed against a counter bearing 515 of the valve body. The valve body comprises an annular outer contour 517, which is connected to the counter bearing 515, in particular via radially inwardly extending ridges 519. Recesses through which blow-by gases can flow are provided between the ridges 519. The thickness and/or outer diameter of the valve member may be set such that the valve member 503 bends around the thrust bearing 515 depending on the pressure difference at the valve between charging pressure and intake pressure, so that the flow resistance of the non-return valve is reduced in the open state. A ratio of the outer diameter of the valve member to the thickness of the valve member may be at least 10/1, 12/1, 15/1, 17/1, 19/1 and/or up to 21/1, 25/1, 29/1, 33/1, 37/1 or 41/1. A ratio of the outer diameter of the valve member to the outer diameter of the counter bearing 515 may be at least 1.5/1, 1.7/1, 1.9/1 and/or at most 2.1/1, 2.3/1, 2.5/1.

[0056] The counter bearing 515 has a trough into which the pin protrudes and which is shaped complementary to the end of the guide pin facing away from the housing, and which is in particular closed in the direction of flow. A phase is provided on the outside of the annular outer contour 517 of the valve body, which is formed in particular complementary to a phase of the housing for inserting a sealing element 505, a sealing ring. The valve member 503 shown in FIGS. 3 and 4 is in particular configured to be exposed to blow-by gases with temperature ranges from 40 C. to +150 C., volume flows of 200 l/min, and/or pressures of two bars for a long time, in particular several years, without losing significant mechanical properties.

[0057] FIG. 5 shows an elastomer component according to one embodiment mounted into a blow-by gas recirculation system, in particular in the form of a mushroom valve 601. FIG. 6 shows a perspective cross-sectional view of the elastomer component in FIG. 5. The elastomer component may be inserted in a system for discharging and feeding blow-by gases, in particular in a recirculation system for blow-by gases. The elastomer component 601 has a cylindrical base body 603 with a rotation axis 607, which extends through an opening 605 when installed. At one end of the base body 603, a contact section 609 is provided for supporting the elastomer component against a wall 611 of the recirculation system forming the opening 605. In the assembled state, the contact section extends radially from the axis of rotation 607 beyond the opening 605. The contact section 609 may have a trapezoidal cross-section, wherein in particular a wider end of the trapezoid is resting against the wall 611 of the recirculation system. On the side of the base body 603 opposite the contact section 609, the elastomer component 601 has a disc-shaped, in particular concave, sealing body 613 for sealing passage openings which are not shown. In particular, blow-by gases exert pressure on the sealing body via the passage openings not shown. If a predetermined pressure, in particular 0.3 bar, is exceeded, the sealing body deforms, in particular elastically, in such a way that a passage, in particular an annular gap, is formed between the sealing body 613 and wall 611. In this condition, blow-by gases can pass through the passage openings and the passage of the elastomer component, in particular the non-return valve, in particular in the form of a mushroom valve. A counter bearing surface 615 extends radially outwards from the outer surface of the base body on the side of the sealing body 613 facing the contact section. The counter bearing surface extends annularly in radial direction, in particular in a plane defined by the axis of rotation as normal vector. Furthermore, the disc-shaped sealing body 613 has a radial, in particular circular outer edge 617 on the side facing the contact section 609. If the pressure is below the predetermined pressure, the outer edge 617 is pressed against the wall 611 of the recirculation system, in particular by elastic deformation restoring forces, so that blow-by gases cannot pass the elastomer component, in particular the non-return valve, in particular in the form of a mushroom valve, through the passage openings. A conical section 619 of the disc-shaped sealing body 613 extends radially inwards from the outer edge 617 and axially away from the contact section 609. The inclination of the conical section in the assembled, unloaded state of the elastomer component is 5, 10, 15, 20, 25, or 30. Due to the pressures of blow-by gases, the sealing body deforms, in particular elastically, in such a way that the angle of inclination is reduced. The thickness of the conical section 619 increases radially from the outside to the inside in particular. Furthermore, a recess 621 is provided in the elastomer component, in particular a conical recess. The recess 621 extends axially, in particular centrally, from the side of the sealing body 613 facing away from the contact section into the base body 603, in particular through the base body into the contact section 609. The recess 621 is open on the sealing body side and closed on the contact section side.

[0058] The elastomer component shown in FIGS. 5 and 6 is particularly configured to endure blow-by gases in a temperature range from 40 C. to +150 C., volume flows from 20 l/min to 200 l/min, and/or pressures of two bars for a long time, in particular several years, without losing significant mechanical properties. Furthermore, the elastomer component according to the invention is configured to provide an elastic closing pressure of at least 150 mbar, 250 mbar, and/or a maximum of 300 mbar, 350 mbar, 400 mbar, or 500 mbar.

[0059] Another embodiment of an elastomer component according to the invention is shown in FIGS. 7 and 8. FIG. 7 shows a pressure control valve comprising a valve cover 705, an elastomer component, in particular as an actuator in the form of a diaphragm 703, a housing portion 707 of a recirculation system, a blow-by gas supply duct 709 and an intake socket 711. FIG. 8 shows a perspective cross-sectional view of the elastomer component from FIG. 7. It comprises in particular a disc-shaped throttle surface 713, which is formed in particular complementary to the outer wall of the intake socket 711, the intake socket being formed as a hollow cylinder. In particular, the distance between the throttle surface and the intake socket 711 varies depending on the intake pressure by moving the throttle surface towards or away from the intake socket, in particular by elastic deformation of the elastomer component. The pressure in the crankcase is controlled by the variable distance between the throttle surface and the intake socket 711. The elastomer component further comprises a mounting portion 715 for mounting the elastomer component, between the valve cover 705 and the housing portion of the recirculation system 707 The mounting portion 715 and the throttling surface 713 may be connected to each other via a spring section 717 of the elastomer component, in particular when implemented in one piece. In one embodiment, the elastomer component is implemented rotationally symmetrical. Starting from the central axis of rotation, the disc-shaped throttle surface 713 extends radially, in particular planar, outwards. The spring section 717 extends radially from the outer surface of the throttle surface 713 to the mounting portion 715, the spring section having in the radial direction in particular a curved contour, in particular an S-shaped contour.

[0060] The spring section 717 extends particularly starting from the radial outer edge of the throttle surface 713 in a first axial direction, away from the intake socket, and then radially outwards to the mounting portion 715. The spring section may have two disc-shaped surfaces, which are spaced apart from one another in the axial direction. In particular, a first disc-shaped spring surface 719, which is connected to the throttle surface 713, and is axially spaced from the throttle surface 713 in a first direction and, in particular, a second spring surface 721, which is connected to the mounting portion 715, is axially spaced from the first spring surface 719 in the opposite axial direction. The first axial direction may point away from the intake socket and the second axial direction towards the intake socket. Furthermore, in the unstressed state of the elastomer component, the first spring section extends axially substantially at the level of the mounting portion 715 and/or the second spring section 721 extends substantially at the level of the throttling surface 713. The two disc-shaped spring sections may be connected to one another via a conical spring section 723. One of the spring faces 719, 721, in particular the first spring face 719, serves to receive a spring, in particular a compression spring, which exerts a force on the elastomer component, in particular against the suction pressure.

[0061] As shown in FIG. 7, the elastomer component according to the invention, in particular in the form of a diaphragm 703, is attached to the outside of the elastomer component via an annular connecting portion. The mounting potion 715 is enclosed by the valve cover 705 on the one side and the housing portion of the recirculation system on the other side. Therefor in particular, a recess 726 complementary to the mounting portion 715 is provided in the valve cover.

[0062] The pressure control valve, in particular the elastomer component, in particular in the form of a diaphragm for a pressure control valve, is configured to set a crankcase pressure between +100 mbar and 200 mbar, or between +50 mbar and 100 mbar, may be between +20 mbar and 100 mbar, at an intake pressure between 0.9 bar, 0.7 bar, 0.5 bar, or 0.3 bar and 0 bar. Further, the pressure control valve, in particular the elastomer component, is configured to endure temperatures of 40 C. to 150 C. in the long term and to permit blow-by gas volume flows into the intake sockets 711 between 0 l/min and 200 l/min.

LIST OF REFERENCE NUMERALS

[0063] 1 blow-by gas circuit [0064] 3 reciprocating piston engine [0065] 5 air inlet [0066] 7 exhaust [0067] 9 recirculation system [0068] 13 cylinder [0069] 19 oil mist separator [0070] 23 piston [0071] 25 compressor [0072] 29 pressure control valve [0073] 33 crankcase [0074] 35 throttle [0075] 39 flow splitter [0076] 43 crank drive [0077] 49, 45, 59 non-return valve [0078] 53 oil pan [0079] 63 cylinder head [0080] 75 throttle valve [0081] 119 oil separator feeding line [0082] 125 compressor line [0083] 129, 229 suction feeding line [0084] 135 ventilation system [0085] 219 oil return line [0086] 249 valve body [0087] 319 separator outlet line [0088] 329 diaphragm [0089] 409 recirculation system [0090] 411 recirculation system housing [0091] 413 housing body [0092] 415 housing base [0093] 417 return inlet [0094] 419, 421 return outlets [0095] 423 first recirculation chamber [0096] 425 oil separator [0097] 427 second recirculation chamber [0098] 429 bypass valve [0099] 431 pressure control valve [0100] 433 third recirculation chamber [0101] 435, 437 non-return valves [0102] 439 cylindrical intake socket [0103] 441 oil return socket [0104] 443 seals [0105] 501 valve body [0106] 503 seal washer [0107] 505 sealing means [0108] 507 housing [0109] 509 housing openings [0110] 511 opening [0111] 513 guide pin [0112] 515 counter bearing [0113] 517 annular outer contour [0114] 519 valve housing ridges [0115] 601 mushroom valve [0116] 603 cylindrical base body [0117] 605 bypass opening [0118] 607 axis of rotation [0119] 609 contact section [0120] 611 wall of the recirculation system [0121] 613 disc-shaped sealing body [0122] 615 counter bearing surface of the sealing body [0123] 617 outer edge of the disc-shaped sealing body [0124] 619 conical section [0125] 621 conical recess [0126] 701 pressure control valve [0127] 703 diaphragm [0128] 705 valve cover [0129] 707 housing portion of a recirculation system [0130] 709 blow-by gas supply duct [0131] 711 intake socket [0132] 713 disc-shaped throttle surface [0133] 715 mounting portion [0134] 717 spring section [0135] 719, 721 disc-shaped spring sections [0136] 723 conical spring section [0137] 726 recess in control valve cover