DE102020116957B3 - Air supply control valve for an internal combustion engine - Google Patents

Abstract

Air supply control valve for an internal combustion engine, with a housing (12) which has an inlet (20) and an outlet (22), a valve closing member (28) which is arranged on a valve rod (30) and a valve seat (26) has a flow cross-section (24) limited between the inlet (20) and the outlet (22), the valve closing member (28) being adjustable at least between a closed position and an open position, a pneumatically operated actuator (40) for adjusting the valve closing member (28), wherein the pneumatically operated actuator (40) has a main diaphragm (42) which can be moved in the axial direction relative to the valve rod (30) and which fluidically separates a first space (18) from a second space (46) and connects to the valve rod ( 30) is operatively connected, the first space (18) being fluidically connected to the inlet (20) and an inlet pressure acting on the membrane (42). To ensure the function ality of the air supply control valve (10), an additional membrane (110) is arranged in the second space (46), which is fixedly arranged on the valve rod (30) and the second space (46) in a first space (120) and a second space (122 ) separates, the first intermediate space (120) being delimited by the main membrane (42) and the additional membrane (110) and optionally connectable to the inlet (20) or to the environment.

Description

The invention relates to an air supply control valve for an internal combustion engine, with a housing which has an inlet and an outlet, a valve closing member which is arranged on a valve rod and with a valve seat delimits a flow cross section between the inlet and the outlet, the valve closing member at least between one Closed position and an open position is adjustable, a pneumatically operated actuator for adjusting the valve closing member, wherein the pneumatically operated actuator has a main membrane movable in the axial direction relative to the valve rod, which fluidically separates a first space from a second space and is operatively connected to the valve rod via a transmission device is, wherein the first space is fluidically connected to the inlet and an inlet pressure acts on the main membrane.

Such air supply control valves are usually used in air supply control systems to inject secondary air into the exhaust gas tract of an internal combustion engine, with the secondary air injection making it possible to reduce the pollutant during the cold start phase. During the cold start phase, secondary air is fed to the rich mixture, which is required for a cold start, in the exhaust system upstream of the catalytic converter, whereby post-combustion takes place which, in addition to reducing carbon monoxide and unburned hydrocarbons, also leads to faster heating of the catalytic converter due to the heat generated.

Such an air supply control valve is, for example, from DE 22 54 961 B and from the DE 692 03 100 T2 known, wherein the air supply control valve has a plurality of control spaces which are delimited by a plurality of membranes attached to a valve rod. Depending on the pressures prevailing in the control chambers, a valve closing element attached to the valve rod is shifted into different positions, the pressures prevailing in the control chambers acting on the diaphragm and causing the valve rod and valve closing element to shift.

Such an air supply control valve is also, for example, from AT 16539 U1 known. The air supply control valve has a housing which has a flow channel with an inlet and an outlet. The inlet is fluidically connected to a pump and can be fluidically connected to the outlet or shut off from the outlet via a controllable flow cross-section. The flow cross-section is limited by a valve seat and a valve closing element. The valve closing member is attached to a first axial end of a valve rod. A membrane engages a second axial end of the valve rod, the membrane having an opening into which the valve rod engages. The membrane is adjoined by a space which can be connected to the inlet, the inlet pressure prevailing in the space loading the membrane in the opening direction of the valve closing member. As soon as the inlet pressure in the space and in the inlet and thereby the force on the membrane caused by the inlet pressure exceeds the spring force of a return spring, the membrane, the valve rod and the valve closing element move from the closed position in the opening direction of the valve closing element. In order to increase the opening force caused by the inlet pressure to adjust the valve closing member in the opening direction and thus to ensure reliable opening of the air supply control valve, the membrane is operatively connected to the valve rod via a transmission device, in particular a lever device. The transmission device converts the force caused by the inlet pressure and acting on the membrane into an opening force acting on the valve rod for adjusting the valve rod and the valve closing member in the opening direction, the membrane and the valve rod moving relative to one another. If the air supply control valve is to be closed while the inlet pressure continues to be high, the connection between the inlet and the room is separated and the room is connected to the environment, so that the diaphragm is pressure-balanced and this together with the valve rod and the valve closing element is relieved by the return spring Closed position is moved.

A disadvantage of such designs of the air supply control valve is that in the closed position of the valve closing element there is a risk that at high inlet pressures the valve closing element will be unintentionally displaced in the opening direction and the air supply control valve will be opened unintentionally. The reason for this is that the inlet pressure also causes a force in the opening direction on the valve closing member, the force at a high inlet pressure exceeding the restoring force of the restoring spring and the air supply control valve being opened. A predefined functionality of the air supply control valve is therefore not guaranteed.

The task is therefore to create an air supply control valve which ensures reliable closing and thereby the functionality of the air supply control valve is guaranteed.

This object is achieved by an air supply control valve for an internal combustion engine with the features of main claim 1.

The fact that an additional membrane is arranged in the second space, which is on the valve rod is fixed and separates the second space into a first space and a second space, the first space being delimited by the main membrane and the additional membrane and optionally connectable to the inlet or to the environment, the closing can be done in a simple and inexpensive manner of the air supply control valve can be guaranteed even at a high inlet pressure. When the flow cross-section is closed, the main diaphragm is pressure-balanced and the return spring loads the valve rod in the closing direction. The high inlet pressure acts on the valve closing element and on the additional diaphragm, the inlet pressure applied to the additional membrane causing a force in the closing direction of the valve closing element and the inlet pressure applied to the valve closing element causing a force in the opening direction. In the closed state of the air supply control valve, the spring force of the return spring and the force resulting from the inlet pressure acting on the additional diaphragm exceed the force in the opening direction which is caused by the inlet pressure acting on the valve closing member. As a result, the air supply control valve can be reliably closed and kept closed regardless of the inlet pressure.

A switching valve is preferably provided, wherein in a first position of the switching valve the first intermediate space delimited by the main diaphragm and the additional diaphragm is connected to the environment and in a second position of the switching valve the first intermediate space delimited by the main diaphragm and the additional diaphragm is connected to the Inlet is connected. The switching valve allows the mode of operation to be implemented in a simple and inexpensive manner, using a simple and inexpensive 3/2-way valve which reliably connects and separates the second space with the inlet.

In a preferred embodiment, the switching valve is integrated in the housing, the switching valve being fluidically connected to the inlet via a first air duct provided in the housing, fluidically connected to the second space via a third air duct provided in the housing, and fluidically connected to the environment via a ventilation duct connected is. In a preferred embodiment, the housing has a housing base body and a housing cover, the third air duct extending through the housing base body and the housing cover. As a result, a compact air supply control valve can be created, with no additional hose connections prone to failure having to be provided between the switching valve and the inlet or the second space.

The switching valve preferably has a closing element, the closing element being designed such that in a first position a first sealing surface of the closing element closes the first air duct and in a second position a second sealing surface of the closing element closes the second air duct connected to the environment. In this way, the ventilation duct, i.e. the second air duct, or the first air duct can optionally be closed by a single closing element. This reduces the number of parts of the air supply control valve.

The additional membrane preferably has a rigid central element and a flexible, annular outer element, the rigid central element being fastened to the valve rod in a fluid-tight manner and the outer element being fastened to the housing in a fluid-tight manner. As a result, the additional diaphragm has sufficient strength and rigidity for reliable connection to the valve rod, the displaceability of the additional diaphragm being possible through the flexible outer element.

The flexible, annular outer element is preferably molded onto the rigid central element and / or onto the housing. This allows the tightness between the two spaces to be increased.

In a preferred embodiment, a separate fastening element is provided on which the transmission device engages and on which the additional membrane is fastened. The installation of the additional membrane and the transmission device can be simplified by the separate fastening element.

The fastening element is preferably fastened to the valve rod via a press connection and / or a form-fitting connection. This creates a connection between the fastening element and the valve rod that is reliable and easy to produce.

In a preferred embodiment, a flexible sealing collar is arranged on the main diaphragm, which is fastened in a fluid-tight manner to the valve rod and to the main diaphragm. As a result, the second space can be reliably separated fluidically from the first space. The sealing collar can be molded onto the main membrane and / or onto the valve rod, which improves the tightness between the two spaces.

The transmission device preferably has at least one lever which is rotatably mounted on the valve rod via a bearing section and is supported on the main diaphragm via a support section, the lever being axially is mounted rocker-like on the housing between the bearing section and the support section. Through the transmission device, in the opening process of the air supply control valve, the force caused by the inlet pressure and acting on the main diaphragm can be converted into a higher force acting on the valve rod, whereby the air supply control valve can be opened even at low inlet pressures.

An air supply control valve for an internal combustion engine is created, which ensures reliable closing even at high inlet pressures, whereby the functionality of the air supply control valve is guaranteed.

An embodiment of an air supply control valve according to the invention is shown in the figure and is described below.

Figure shows a sectional view of an air supply control valve according to the invention.

The figure shows an air supply control valve 10 in a sectional view. The air supply control valve 10 includes a housing 12th with a housing body 14th and a two-part housing cover 16 , with the housing cover 16 on the housing body 14th is attached. The case 12th delimits a flow channel 18th , which has an inlet 20th with an outlet 22nd fluidically connects. The inlet 20th is with a secondary air line not shown in the figure and the outlet 22nd is fluidically connected to an exhaust tract of a motor vehicle, also not shown in the figure. In the flow channel 18th is a flow cross-section 24 provided, which by one on the housing body 14th arranged valve seat 26th and a valve closing member 28 is limited. The valve closing member 28 is on a valve stem 30th attached.

Between the valve stem 30th and the housing body 14th is a return spring 32 arranged which the valve rod 30th surrounds radially. The return spring 32 is supported at the end on an inner surface 34 of the housing body 14th and on a radial projection 36 and loads the valve rod 30th axial. The return spring 32 is designed as a helical spring, in particular a compression spring, and loads the valve rod 30th and the valve closing member 28 in the closing direction.

The adjustment of the valve closure member 28 and the valve stem 30th between an open and a closed position is carried out by a pneumatically operated actuator 40 . The pneumatically operated actuator 40 includes a main membrane 42 . The main membrane 42 has a relatively rigid central element 44 and a thin, flexible edge element 47 on, being the main diaphragm 42 with the edge element 47 between the housing body 14th and the housing cover 16 Is clamped airtight and in this way a first space, ie the flow channel 18th or the inlet 20th associated section of the flow channel 18th , from one to the the flow channel 18th facing away from the main membrane 42 arranged second room 46 separates.

The main membrane 42 points in the middle element 44 a through opening 48 through which the valve rod 30th extends and having an end portion 50 in the through the housing 12th and the main membrane 42 limited space 46 protrudes. A gap 51 between a peripheral surface 52 the valve stem 30th and a peripheral surface 54 the passage opening 48 is through a sealing sleeve 56 sealed airtight. The sealing sleeve 56 is made of an elastomer and attached to the main membrane 42 molded on, with the sealing collar 56 an opening 58 for the valve rod 30th has and the valve rod 30th fluid-tight with the sealing sleeve 56 connected is.

The force-transmitting connection between the main membrane 42 and the valve stem 30th takes place via a transmission device 60 of the pneumatically operated actuator 40 . The transmission device 60 includes two levers 62 , 64 , which each have a bearing section arranged at one axial end 66 , 67 on the valve stem 30th are rotatably mounted, the axis of rotation 70 perpendicular to the longitudinal axis 72 the valve stem 30th is aligned. The levers 62 , 64 are supported with a support section arranged at a second axial end 68 , 69 on the main membrane 42 away. To reduce the friction between the respective lever 62 , 64 and the main membrane 42 are on the support section 68 , 69 one role each 74 , 75 arranged, which are rotatably mounted. The main membrane 42 can via at least one spring element, not shown in the figure, in the direction of the lever 62 , 64 be axially loaded, causing the main diaphragm 42 permanently on the rollers 74 , 75 the lever 62 , 64 is present.

On the main membrane 42 are several spacers 43 , 45 provided, which in the closed state of the air supply control valve 10 on one by a spring element 31 axially loaded check plate 29 of the valve closing element 28 abut, causing the non-return plate 29 of their on the housing body 14th provided sealing surface is pushed away and thereby in the closed state of the air supply control valve 10 gluing the non-return plate 29 with their sealing surface is prevented. When the air supply control valve is open 10 are the spacer elements 43 , 45 from the check plate 29 spaced and strain the non-return plate 29 not.

Furthermore are the levers 62 , 64 via one between the support section 68 , 69 and the storage section 66 , 67 arranged lever bearing 63 , 65 on the housing cover 16 mounted like a rocker, the lever bearings 63 , 65 through one on the housing cover 16 provided projection 76 , 77 are executed.

By choosing the distance between the bearing section 66 , 67 and the lever mounting 63 , 65 and the distance between the support section 68 , 69 and the lever mounting 63 , 65 a force transmission unequal to 1 is set, whereby according to the law of levers one from the displacement of the main diaphragm 42 resulting force in a on the valve rod 30th acting force is translated. In the present case, the distance between the bearing section is 66 , 67 and the rocker-like lever mounting 63 , 65 smaller than the distance between the support section 68 , 69 and the rocker-like lever mounting 63 , 65 which causes the on the valve stem 30th acting force is higher than that caused by the displacement of the main diaphragm 42 caused force.

The air supply control valve 10 further comprises an in the housing 12th integrated switching valve 41 . Alternatively, the switching valve could 41 also outside the housing 12th be arranged. The switching valve 41 has an electromagnetic actuator 80 with a coil 82 , a core 84 and an anchor 86 on, being at anchor 86 a closing element 88 is attached. The closing element 88 has a sealing surface on each of its end faces 90 , 92 on, with a first sealing surface 90 to close one with the inlet 20th connected, first air duct 94 serves and a second sealing surface 92 for closing a second air duct connected to the environment 96 serves. Furthermore, the switching valve 41 one with the second room 46 connected, third air duct 98 on. The third air duct 98 extends through the housing body 14th and through the housing cover 16 .

The switching valve 41 has two switching positions, the actuator in a first switching position 80 is not energized and the armature 86 and thus the closing element 88 exclusively through a spring element 100 are burdened. Here is the one with the inlet 20th connected first air duct 94 closed and the second air duct connected to the environment 96 open, creating the second air duct 96 over an annular gap 102 with the third air duct 98 connected is. This is the space 46 connected to the environment and in space 46 ambient pressure prevails. The actuator is in the second switch position 80 energized, the armature 86 against the spring force of the spring element 100 is shifted, creating the second air duct 96 is closed and a connection between the first air duct 94 and the third air duct 98 is made. Here is the room 46 with the inlet 20th connected, creating in space 46 Inlet pressure prevails.

In the closed state of the air supply control valve 10 is the switching valve 41 energized so that the switching valve 41 is in the second switching position and the inlet 20th with the space 46 connected is. This acts on the main membrane 42 the inlet pressure on both sides, creating the main diaphragm 42 is pressure balanced. The return spring 32 caused by their counter to the opening direction of the valve closing member 28 , ie in the closing direction, acting spring force that the valve closing member 28 against the valve seat 26th is pressed and thereby the flow cross-section 24 closed is.

The inlet pressure acts when the valve closing element is closed 28 also on the valve closure member 28 itself and causes a force in the opening direction of the valve closing member 28 . At a high inlet pressure there is the risk that the valve closing element 28 , the force acting in the opening direction is the spring force of the return spring 32 exceeds, whereby the valve closing member 28 from the valve seat 26th lifts off and the air supply control valve 10 is opened unintentionally.

According to the invention is in the second room 46 an additional membrane 110 arranged, which on the valve rod 30th is attached. The additional membrane 110 has a rigid central element 114 and a flexible, annular outer member 116 on, with the central element 114 on the valve stem 30th is attached and the outer element 116 on the housing cover 16 is attached fluid-tight. The attachment of the central element 114 on the valve stem 30th takes place via a separate fastening element 112 on which the additional membrane 110 is attached and which is used as a storage for the lever 62 , 64 the transmission device 60 serves. The separate fastener 112 is via a press connection at one axial end of the valve rod 30th attached.

The additional membrane 110 separates the second room 46 in a first space 120 and a second space 122 . The first space 120 is through the main membrane 42 and the additional membrane 110 limited. The second space 122 is through the additional membrane 110 and the housing cover 16 limited, the second gap 122 is permanently connected to the environment.

Through the additional membrane 110 is achieved that the air supply control valve 10 can be reliably closed and kept closed even at a high inlet pressure. The one in the closed state of the air supply control valve 10 in the room 46 The prevailing inlet pressure also acts on the additional diaphragm 110 , making the valve rod 30th in the closing direction of the valve closing member 28 is loaded and the return spring 32 when closing the flow cross-section 24 supports. The resulting force is like that on the valve closing member 28 acting force depends on the inlet pressure. As a result, when the inlet pressure increases, both opposing forces, which are dependent on the inlet pressure, increase, with the force acting in the closing direction and dependent on the inlet pressure on the additional diaphragm 110 and the spring force of the return spring acting in the closing direction 32 the force acting in the opening direction and dependent on the inlet pressure on the valve closing element 28 exceed at any time, causing an undesirable opening of the flow cross-section 24 is prevented.

To open the air supply control valve 10 becomes the switching valve 41 not energized, which means the room 46 is connected to the environment. The inlet pressure acts on one side of the membrane 42 and causes a direction opposite to the opening direction of the valve closing member 28 acting force on the main membrane 42 , making the main membrane 42 opposite to the opening direction of the valve closing member 28 relocated. The movement of the main diaphragm opposite to the opening direction 42 is through the transmission device 60 in a movement of the valve rod 30th in the opening direction of the valve closing member 28 transferred. In addition, through the transmission device 60 those on the valve stem 30th acting force increased.

It thus becomes an air supply control valve 10 created, which ensures reliable closing even at high inlet pressures, thereby reducing the functionality of the air supply control valve 10 is guaranteed.

It should be clear that the scope of protection of the present main claim is not limited to the exemplary embodiment described. So, of course, there are changes in the construction of the various parts of the air supply control valve 10 like the case 12th or the arrangement of the valve parts to one another is conceivable.

List of reference symbols

10

Air supply control valve

12th

casing

14th

Housing body

16

Housing cover

18th

Flow channel

20th

inlet

22nd

Outlet

24

Flow cross-section

26th

Valve seat

28

Valve closing member

29

Check plate

30th

Valve stem

31

Spring element

32

Return spring

34

Inner surface

36

Radial projection

40

Actuator

41

Switching valve

42

Main membrane

43

Spacer element

44

Central element

45

Spacer element

46

second room

47

Edge element

48

Through opening

50

End section

51

gap

52

Circumferential surface

54

Circumferential surface

56

Sealing sleeve

58

opening

60

Transmission device

62

lever

63

Lever bearing

64

lever

65

Lever bearing

66

Warehouse section

67

Warehouse section

68

Support section

69

Support section

70

Axis of rotation

72

Longitudinal axis

74

role

75

role

76

head Start

77

head Start

80

electromagnetic actuator

82

Kitchen sink

84

core

86

anchor

88

Closing element

90

Sealing surface

92

Sealing surface

94

first air duct

96

second air duct

98

third air duct

100

Spring element

102

Annular gap

110

Additional membrane

112

Fastener

114

Central element

116

Outer element

120

first space

122

second space

Claims (11)

Air supply control valve (10) for an internal combustion engine, with a housing (12) which has an inlet (20) and an outlet (22), a valve closing member (28) which is arranged on a valve rod (30) and with a valve seat (26) ) a flow cross-section (24) between the inlet (20) and the outlet (22), the valve closing member (28) being adjustable at least between a closed position and an open position, a pneumatically operated actuator (40) for adjusting the valve closing member (28) , wherein the pneumatically operated actuator (40) has a main diaphragm (42) movable in the axial direction relative to the valve rod (30), which fluidically separates a first space (18) from a second space (46) and via a transmission device (60) the valve rod (30) is operatively connected, the first space (18) being fluidically connected to the inlet (20) and an inlet pressure acting on the membrane (42), characterized in that that in the second space (46) an additional membrane (110) is arranged, which is fixedly arranged on the valve rod (30) and separates the second space (46) into a first space (120) and a second space (122), the The first intermediate space (120) is delimited by the main membrane (42) and the additional membrane (110) and can optionally be connected to the inlet (20) or to the environment. Air supply control valve (10) Claim 1 , characterized in that a switching valve (41) is provided, wherein in a first position of the switching valve (41) the first intermediate space (120) delimited by the main diaphragm (42) and the additional diaphragm (110) is connected to the environment and in a second position of the switching valve (41) which is connected to the inlet (20) by the first intermediate space (120) delimited by the main diaphragm (42) and the additional diaphragm (110). Air supply control valve (10) Claim 2 , characterized in that the switching valve (41) is integrated in the housing (12), the switching valve (41) being fluidically connected to the inlet (20) via a first air duct (94) provided in the housing (12), via an im Housing (12) provided, the third air duct (98) is fluidically connected to the second space (46) and is fluidically connected to the environment via a second air duct (96). Air supply control valve (10) Claim 3 , characterized in that the housing (12) has a housing base body (14) and a housing cover (16), the third air duct (98) extending through the housing base body (14) and the housing cover (16). Air supply control valve (10) Claim 3 or 4th , characterized in that the switching valve (41) has a closing element (88), the closing element (88) being designed such that in a first position a first sealing surface (90) of the closing element (88) closes the first air duct (94) and in a second position a second sealing surface (92) of the closing element (88) closes the second air duct (96) connected to the environment. Air supply control valve (10) according to one of the preceding claims, characterized in that the additional membrane (110) has a rigid central element (114) and a flexible, annular outer element (116), the rigid central element (114) on the valve rod (30) being fluid-tight is attached and the outer element (116) is attached to the housing (12) in a fluid-tight manner. Air supply control valve (10) Claim 6 , characterized in that the flexible, ring-shaped outer element (116) is injection-molded onto the rigid central element (114) and / or onto the housing (12). Air supply control valve (10) according to one of the preceding claims, characterized in that a separate fastening element (112) is provided on which the transmission device (60) engages and on which the additional membrane (110) is fastened. Air supply control valve (10) Claim 8 , characterized in that the fastening element (112) via a press connection and / or a Form-fitting connection is attached to the valve rod (30). Air supply control valve (10) according to one of the preceding claims, characterized in that a flexible sealing sleeve (56) is arranged on the main diaphragm (42) and is fastened in a fluid-tight manner to the valve rod (30) and to the main diaphragm (42). Air supply control valve (10) according to one of the preceding claims, characterized in that the transmission device (60) has at least one lever (62, 64) which is rotatably mounted on the valve rod (30) via a bearing section (66, 67) and via a Support section (68,69) is supported on the main membrane (42), the lever (62, 64) being mounted axially between the bearing section (66, 67) and the support section (68, 69) on the housing (12) like a rocker.

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