EP1498596B1 - Throttle slit seal for valves - Google Patents

Description

The invention relates to a throttle gap seal according to the preamble of claim 1 for valves which control the flow of gaseous media in internal combustion engines cyclically (i.e., per cycle) and exhibit very low leak rates when closed.

1. 1. Thermodynamisch erforderliche sehr geringe Leckagen im geschlossenen Zustand des Ventils können nur mit Dichtspalthöhen zwischen Stellglied und Gehäuse in der Größenordnung von einigen 1/100 mm unterboten werden.
2. 2. Das Ventil muss in sehr kleinen Zeitintervallen, die in der Größenordnung von einigen Millisekunden liegen öffnen bzw. schließen können.
3. 3. Wegen der hohen Beschleunigungen des Stellglieds bedingt durch kurze Schaltzeiten, muß das Stellglied geringe Masse bzw. Trägheitsmomente besitzen, aber bezüglich der Erhaltung der Dichtspaltgeometrie Formsteifigkeit aufweisen.
4. 4. Das Ventil muss eine Lebensdauer von bis zu 100 Millionen Schaltspielen bewältigen können
5. 5. Die Durchflusscharakteristik des Ventils, d.h. auch die Leckage im geschlossenen Zustand darf sich über die Lebensdauer nicht signifikant verändern.
6. 6. Das Ventil muss in einem weiten Temperaturbereich, (frischluftseitig ca. - 30°C bis ca. 120°C), (abgasseitig ca. -30°C bis ca. 1000°C) funktionsfähig bleiben und konstante Leckage aufweisen.
7. 7. Das Ventil muss eine annähernd konstante Dichtspalthöhe auch unter hohen zeitlichen Temperaturgradienten des zu steuernden Mediumsflusses behalten, da signifikante Veränderungen der Dichtspalthöhe im geschlossenen Zustand des Ventils entweder stark zunehmende Leckage oder zunehmende Reibung und Verschleiß der Dichtspalt bildende Bauteile zur Folge haben.
8. 8. Die Reibung im Dichtsystem des Ventils muss unter allen Betriebsbedingungen annähernd konstant bleiben, um Wärmeeintrag in das zu steuernde Medium zu minimieren und den Leistungsaufwand zum Antrieb des Ventils auf einem niedrigen Niveau zu halten.
9. 9. Mechanische Schaltgeräusche beim Öffnen und Schließen des Ventils sind unerwünscht.

The use of valves for gas exchange control in internal combustion engines places the following requirements on the valve:

1. 1. Thermodynamically required very small leaks in the closed state of the valve can only be undercut with sealing gap heights between actuator and housing in the order of a few 1/100 mm.
2. 2. The valve must be able to open or close in very small time intervals, which are on the order of a few milliseconds.
3. 3. Due to the high accelerations of the actuator due to short switching times, the actuator must have low mass or moments of inertia, but have with respect to the preservation of the sealing gap geometry stiffness.
4. 4. The valve must be able to handle a lifetime of up to 100 million operations
5. 5. The flow characteristics of the valve, ie the leakage in the closed state must not change significantly over the lifetime.
6. 6. The valve must remain functional over a wide temperature range (fresh air side approx. - 30 ° C to approx. 120 ° C), (exhaust gas approx. -30 ° C to approx. 1000 ° C) and show constant leakage.
7. 7. The valve must maintain an approximately constant sealing gap height even under high temporal temperature gradients of the medium flow to be controlled, since significant changes in the sealing gap height in the closed state of the valve either greatly increasing leakage or increasing friction and wear of the sealing gap forming components result.
8. 8. The friction in the sealing system of the valve must remain approximately constant under all operating conditions in order to minimize heat input into the medium to be controlled and to keep the power required to drive the valve at a low level.
9. 9. Mechanical switching noises when opening and closing the valve are undesirable.

This o.g. Requirements can not fully meet known valve designs, as these have depending on the design, either plant seals or non-adjustable gap seals and design are specifically associated with the following constructive disadvantages:

Disadvantages of valves with actuator moved perpendicular to the system seals:

• The movement of the actuator in the closed position against the plant seal is affected attack
• The stopper causes noise, friction and wear on the plant seal and on the actuator
• The stop requires a very precise path control of the actuator in its closed position
• If the axis of rotation of the actuator intersects the flow cross-section, the plant seal to the actuator is necessarily interrupted (increased leakage)
• The leakage at the valve is pressure-direction-dependent because of the asymmetry of the system seal
• The leakage depends on the wear of the system seal
• Due to their intrusion into the flow cross-section, the system seal represents an increased hydraulic flow resistance
• The introduction of the system seal in the housing represents a considerable installation effort with high sensitivity to the leakage

Disadvantages of valves with tangentially moved to the plant seals actuator:

• The continuous contact of the plant seal and the actuator causes friction, wear and wear-dependent leakage
• Because of the friction, a higher drive power is required on the actuator and the heat input into the valve and the medium increases
• The leakage at the valve is pressure-direction-dependent because of the asymmetry of the system seal
• The introduction of the system seal in the housing represents a considerable installation effort with high sensitivity to the leakage

Disadvantages of valves with non-adjustable gap seals:

• Manufacturing tolerances with respect to the position of the actuator to the housing cause non-correctable deviations from the ideal gap geometry
• Deviations from the ideal gap geometry cause large differences in leakage.
• Non-adjustable distances of the sealing surfaces between the actuator and housing can cause friction, clamping tendency and wear when touched.

A throttle gap seal according to the preamble of claim 1 is known from JP 10 103089 A. To shorten the length of the valve, the housing is provided there with a lateral recess into which the insert can be inserted sealingly. By means of a screw, the insert and the housing are connectable, so that the insert is firmly connected in its inserted into the housing position with this. The actuator of the valve is designed as a throttle valve, which is held rigidly in a bearing shaft for the throttle valve. The bearing shaft itself is not adjustable mounted in the insert.

Against the background of the described requirement on the valve and the disadvantages of known valves, the invention proposes a throttle gap seal according to the features of claim 1.

The throttle gap seal according to the invention thus has an insert, which is received in the housing. This is sealed to the housing with at least one seal. The insert comprises the flow cross-section of the housing and can be aligned, preferably in the closed state of the valve, with the actuator of the valve facing sealing surface to the position of the actuator with the insert facing the sealing surface at least once in the housing. According to a preferred embodiment of the invention, it is provided that the sealing surface of the insert and the sealing surface of the actuator face each other in the closed position of the valve without continuous force. Insertion and actuator are thus free of forces.

Preferably, the actuator assumes its rest-closed position without a stop against the insert and housing. By eliminating a stop, extreme acceleration peaks of the moving parts can be avoided.

It is also considered advantageous in the throttle gap seal, when the sealing surface of the actuator with changing the flow cross-section of the valve with respect to the sealing surface of the insert executes any trajectory, wherein the trajectory of the sealing surface of the actuator to the rest-closing position of the actuator a tangential direction relative to the Includes sealing surface of the insert. This trajectory may, for example, be oscillating and / or rotating, linear, circular, elliptical, parabolic, etc. It performs during the movement process of the actuator of the center of gravity of the actuator relative to the center of mass of the insert any curved path, for example, a rotary motion, a linear displacement, a combination of both forms of motion or no movement.

The seal preferably takes on additional functions in addition to the medium seal, such as the thermal insulation between housing and insert and / or the attachment of the insert in the housing. This case of thermal insulation relates in particular to the static aspect. The thermal insulation between housing and insert ensures, in particular in the event that the valve is arranged in the region of a cylinder head, that the heating of the housing does not transfer to the insert, and thus causes a high temperature difference between the actuator and insert.

From a dynamic point of view, it is advantageous if the actuator and the insert have a similar ratio of medium-flushed component surfaces / heat capacity of the component in order to achieve a similar time behavior with respect to the thermal expansion of the components. This training of actuator and insert considers in particular effects due to strong intake air heating in turbocharged engines.

From the aspect that the valve should switch in the millisecond range, the formation of the moving actuator with low mass is of particular importance. Thus, it is proposed that the actuator consists of one or more individual components, which are made in part of one or more low-density materials, such as light metal, metal foam, plastic foam, fiber-reinforced plastic.

From the aspect of the unique alignment possibility, a preferred embodiment of the invention provides that the throttle sealing gap between actuator and insert is adjustable by positioning the insert in the plane or additionally perpendicular to the plane. This positioning can be done by mechanical (for example distance gauge), optical (for example light gap measurement) or hydraulic (for example gap flow) calibration of the throttle sealing gap. The calibration of the throttle sealing gap can also be done by self-centering of the insert on the actuator. This is preferably done by applying the sealing surface of the valve to the sealing surface of the insert, wherein one of these surfaces is provided with a thick coating, which the throttle gap in the assembled state at least partially closes and which wears off in the subsequent operation of the valve on the opposite, wear-resistant sealing surface.

In the case of the repeated, ie taking place during each opening or closing operation of the actuator aligning the insert in the housing results the throttle sealing gap by automatically returning the orientation of the insert on the actuator in the rest-closed position. This is achieved, for example, by a decreasing throttle gap height in the direction of the rest-closed position. The insert is movable, but medium-tight seals on the housing from and the sealing surfaces of insert and actuator are provided with a wear-resistant surface coating.

Advantageous developments of the invention will become apparent from the other dependent claims.

• Das Dichtungssystem eines solchen Ventils muß berührungslos dichten. Damit wird verschleißfreier Betrieb des Dichtsystems möglich und die Anforderungen 4/5/8/9 werden erfüllt. Ein berührungsloses Dichtsystem ist durch einen Drosseldichtspalt zu erreichen.
• Der Drosseldichtspalt muß bezüglich seiner Spalthöhe und Spaltlage wegen fertigungsbedingter Toleranzen der den Drosseldichtspalt beeinflußenden Bauteile einstellbar sein. Die Einstellbarkeit gewährleistet die Erfüllung der Anforderung 1.
• Die zu beschleunigenden Massen in dem Ventil müssen, um die Anforderungen 2/3 zu erfüllen, so niedrig wie möglich gehalten werden. Aus diesem Grund ist die Vorrichtung zur Einstellbarkeit des Drosselspaltes in die unbewegten Bauteile des Ventils zu legen.
• Das Dichtsystem muß, um den Anforderungen 6/7 zu genügen, in einem weiten Temperaturbereich funktionsfähig bleiben. Dies wird durch eine Temperatur unabhängige Drosselspalthöhe und ein ähnliches Temperatur-Zeit-Verhalten der den Drosseldichtspalt bildenden Bauteile erreicht.

The fulfillment of the above-mentioned requirements 1-9 on valves for gas exchange control in internal combustion engines is achieved by the adjustable, narrow throttle gap seal. The constructive properties of the throttle gap seal are compared to requirements 1-9 below:

• The sealing system of such a valve must seal non-contact. Thus, wear-free operation of the sealing system is possible and the requirements 4/5/8/9 are met. A non-contact sealing system can be achieved through a throttle sealing gap.
• The throttle sealing gap must be adjustable with respect to its gap height and gap position due to manufacturing tolerances of the throttle sealing gap affecting components. Adjustability ensures fulfillment of requirement 1.
• The masses to be accelerated in the valve must be kept as low as possible to meet requirements 2/3. For this reason, the device is to adjust the adjustability of the throttle gap in the stationary components of the valve.
• The sealing system must remain functional over a wide temperature range to meet requirements 6/7. This is achieved by a temperature independent throttle gap height and a similar temperature-time behavior of the throttle sealing gap forming components.

Figur 1

einen Halbschnitt des Ventils in Strömungsebene, beispielhaft mit einem kreisrunden, drehbaren, rotationssymmetrischen Stellglied ausgestattet,

Figur 2

einen Vergrößerungsausschnitt aus Figur 1,

Figur 3

eine Draufsicht des Ventiles nach den Figuren 1 und 2, gezeigt bei geschlossenem Ventil und gesehen in Strömungsrichtung,

Figur 4

einen Halbschnitt des in Figuren 1 bis 3 gezeigten Ventils in Strömungsebene, mit Darstellung der strömungsmechanisch relevanten Position des Stellglieds,

Figur 5

bei dem in den Figuren 1 bis 4 gezeigten Ventil die abtragbare Beschichtung der Dichtfläche des Stellgliedes, womit die Selbstzentrierung des Einlegeteils auf das Stellglied erreicht wird,

Bild 6

bei dem in den Figuren 1 bis 4 gezeigten Ventil die abtragbare Beschichtung der Dichtfläche des Einlegeteils, womit die Selbstzentrierung des Einlegeteils auf das Stellglied erreicht wird,

Bild 7

für das in den Figuren 1 bis 4 gezeigte Ventil die wiederholbare Selbstzentrierung des Einlegeteils auf das Stellglied über eine kleiner werdende Drosselspalthöhe nahe der RuheSchließposition

Further details of the invention are described in the following description of the figures and explained in more detail. In the figures, the invention is illustrated with reference to several embodiments, without being limited thereto. It shows:

FIG. 1

a half-section of the valve in the flow plane, for example equipped with a circular, rotatable, rotationally symmetrical actuator,

FIG. 2

a magnifying section of Figure 1,

FIG. 3

a top view of the valve according to Figures 1 and 2, shown with the valve closed and seen in the flow direction,

FIG. 4

3 shows a half section of the valve shown in FIGS. 1 to 3 in the plane of flow, showing the fluidically relevant position of the actuator;

FIG. 5

in the valve shown in Figures 1 to 4, the abradable coating of the sealing surface of the actuator, whereby the self-centering of the insert is achieved on the actuator,

Picture 6

in the valve shown in Figures 1 to 4, the abradable coating of the sealing surface of the insert, whereby the self-centering of the insert is achieved on the actuator,

Picture 7

for the valve shown in Figures 1 to 4, the repeatable self-centering of the insert onto the actuator over a decreasing throat height near the quiescent closure position

The illustrated in Figure 1 valve 16 has a housing 1 for guiding the gaseous medium in the valve 16. In the housing 1 is a movable drivable, pivotable about the axis of rotation 24 actuator 4 for changing the corresponding flow cross-section 11 provided in the valve. In the housing 1, an insert 2 is added. This is sealed to the housing 1 with a seal 3. As in particular to the illustration of Figure 3 2, the insert part 2 comprises the flow cross-section 11 of the housing 1.

In the figure 1, the actuator 4 is shown in its closed position. The insert 2 can be in the closed state 6 of the valve in its the actuator 4 facing sealing surface 10, as illustrated in particular in Figure 2, at least once in the housing align and form the position of the actuator 4 with the insert 2 facing sealing surface a throttle gap 12. The sealing surface 10 of the insert 2 and the sealing surface 8 of the actuator 4 are, without continuous force on each other, in the closed position 6 of the valve opposite. The actuator 4 assumes its closed position 6 without a stop against the insert 2 and housing 1.

The sealing surface 8 of the actuator 4 performs with a change of the flow cross section 11 of the valve with respect to the sealing surface 10 from a circular path of movement 9. The movement path of the sealing surface 8 to the rest-closing position 6 of the actuator 4 includes a tangential direction 7 relative to the sealing surface 10th

The longitudinal center axis of the housing 1 is denoted by the reference numeral 14, the plane arranged perpendicular to the throttle sealing gap 12 by the reference numeral 15. In the rest position, the actuator 4 is symmetrical to the plane 15. The reference numeral 5, the open, thus pivoted by 90 ° position of the actuator 4 is designated. In FIG. 4, the reference numeral 13 illustrates a position of the actuator 4 when the flow cross-section 11 is released or closed. The throttle sealing gap 12 is present during the closing operation of the valve even before reaching the rest-closing position 6 of the actuator 4 from this position 13, whereby the actuator when closing the flow cross-section 11, a movement speed greater zero is imposed. The throttle sealing gap 12 is maintained during the opening operation of the valve for a portion of the onset of movement of the actuator 4 from its rest-closed position 6 out to its position 13, whereby the actuator 4 at the beginning of release of the flow cross section 11, a movement speed greater than zero is imposed.

The actuator 4 and the insert 2 consists of a material with a similar coefficient of thermal expansion. The seal 3 assumes, in addition to the medium seal, additional functions, in particular the thermal insulation between the housing 1 and insert 2 and / or the attachment of the insert 2 in the housing 1. The actuator 4 and the insert 2 have a similar coefficient of medium lapped component surfaces / Heat capacity of the component to achieve a similar time behavior with respect to the thermal expansion of the components. The actuator 4 is the component surfaces 22 and 23 and the component surface formed by the sealing surface 8 of the actuator 4, and the insert 2 to the component surfaces 17 and 18 and the sealing surface 10 of the insert 2, which forms a further component surface.

The actuator 4 has in the exemplary embodiment a circular disk-shaped outer contour, which closes at least the flow cross-section 11 in the closed position of the valve 6 to the throttle gap 12. Basically, the actuator 4 may consist of one or more individual components, which are made in part of one or more low-density materials, such as light metal, metal foam, plastic foam, fiber-reinforced plastic. Also, the insert 2 may consist of several individual components.

FIGS. 5 to 7 illustrate the special design of the throttle gap seal with reference to three basic embodiments in order to achieve the self-centering of the insert 2 on the actuator 4:

In the embodiment of Figure 5, the self-centering of the insert 2 on the actuator 4 by applying the sealing surface 8 of the actuator 4 takes place on the sealing surface 10 of the insert part 2, wherein the sealing surface 8 of the actuator 4 is provided with a coating 19. This closes or reduces the throttle gap at least in the assembled state and wears off at least partially in later operation on the opposite, wear-resistant sealing surface 10.

The embodiment of Figure 6 differs from that of Figure 5 only in that instead of the coating 19 of the actuator 4, a coating 20 of the insert 2 is provided which closes or reduces the throttle gap at least in the assembled state and in later operation the valve at the opposite, wear-resistant sealing surface 8 of the actuator 4 at least partially ablates.

Figure 7 illustrates an embodiment in which the throttle sealing gap 12 results by automatically recurring the alignment of the insert 2 on the actuator 4 in the rest-closed position 6. This is achieved, for example, by a decreasing throttle gap height 21 in the direction of the rest-closed position 6. The insert 2 closes movable, but medium-tight over two seals 3 to the housing 1 and it are the sealing surfaces 8 and 10 provided with a wear-resistant surface coating. In this embodiment, the insert 2 is elastically fixed in the housing 1.

LIST OF REFERENCE NUMBERS

1

casing

2

insert

3

poetry

4

actuator

5

position

6

closed state of the valve

7

tangential direction

8th

Sealing surface actuator

9

trajectory

10

Sealing surface insert

11

Flow area

12

Throttling sealing gap

13

position

14

Longitudinal central axis

15

Plane transverse to the longitudinal central axis

16

Valve

17

component surface

18

component surface

19

coating

20

coating

21

Throttle gap height

22

component surface

23

component surface

24

axis of rotation

Claims (13)

1. Throttle gap seal for minimizing leakage in cyclically switching valves controlling the through flow of gaseous media on internal combustion engines, with at least one movably actuatable control element (4) for varying the corresponding flow cross-section (11) in the valve, and with at least one insert (2) and at least one casing (1) conducting the gaseous medium in the valve, wherein the insert (2) is seated in the casing (1), the insert (2) is sealed against the casing (1) with at least one seal (3), [and] the insert (2) surrounds the flow cross-section (11) of the casing (1), characterized in that, in the closed condition (6) of the valve, the insert (2) arranged within the casing (1) forms with its sealing face (10) facing towards the control element (4) a throttle seal gap (12) adjustable in its magnitude and position to the position of the sealing face (8) of the control element (4).
2. Throttle gap seal according to Claim 1, characterized in that in the closed condition (6) of the valve, the insert (2) can be positioned in the casing at least once by its sealing face (10) facing towards the control element (4) to the position of the control element (4) in terms of the latter's sealing face (8) facing towards the insert (2).
3. Throttle gap seal according to Claim 1 or Claim 2, [characterized in that] the motion path (9) swept by the sealing face (8) of the control element (4) with respect to the sealing face (10) of the insert ring (2) upon variation in the flow cross-section (11) of the valve is any desired motion path that includes, about the idle/closed position (6), a tangential direction (7) with respect to the sealing face (10) of the insert (2).
4. Throttle gap seal according to any one of Claims 1 to 3, characterized in that the seal (3) assumes additional functions besides sealing-off of medium, in particular thermal insulation between casing (1) and insert (2) and/or fixing of the insert (2) in the casing (1).
5. Throttle gap seal according to any one of Claims 1 to 4, characterized in that during the opening of the valve the throttle seal gap (12) stays the same [for] an initial portion of the movement of the control element (4) from its idle/closed position (6) to a position (13) in which the flow cross-section (11) is unblocked, a greater-than-zero movement velocity being imparted to the control element (4) at the onset of the unblocking of the flow cross-section (11).
6. Throttle gap seal according to any one of Claims 1 to 5, characterized in that the control element (4) possesses any desired three-dimensional outer contour that in the closed position of the valve (6), closes off at least the flow cross-section (11), disregarding the throttle gap (12).
7. Throttle gap seal according to any one of Claims 1 to 6, characterized in that the insert (2) consists of a number of individual components.
8. Throttle gap seal according to any one of Claims 1 to 7, characterized in that positioning of insert (2) and control element (4) to form the throttle seal gap (12) is effected by self-centring of the two components to one another.
9. Throttle gap seal according to Claim 8, characterized in that for the purpose of self-centring the insert (2) on the control element (4), one of the sealing faces (8 or 10) is provided with a coating (19 or 20 respectively), in particular a coating of uniform thickness, which in the assembled condition at least reduces, or closes altogether, the throttle seal gap (12), and in subsequent operation of the valve is at least partly abraded by the opposing, wear-resistant sealing face (10 or 8 as the case may be).
10. Throttle gap seal according to Claim 9, characterized in that the abradable coating (19) is applied to the face (8) of the control element (4) with the insert ring (2) present between the faces (8, 10) of control element [(4)] and insert (2) [sic].
11. Throttle gap seal according to any one of Claims 1 to 10, characterized in that the throttle seal gap (12) is formed by repetitive self-alignment of the insert (2) with the control element (4) in the idle/closed position (6).
12. Throttle gap seal according to any one of Claims 1 to 11, characterized in that the insert is movably yet mediumtightly sealed with respect to the casing (1) by seals (3), and the sealing faces (8,10) of control element (4) and insert (2) are provided with a wear-resistant surface coating.
13. Throttle gap seal according to any one of Claims 1 to 12, characterized in that the guide or mounting of the control element (4) is accommodated in the casing (1) and/or in the insert (2) and/or in other components of the valve.

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