EP1762709B1 - Muffler - Google Patents

Abstract

Mufflers has gas permeable openings (79), which are provided between the housing wall (44) and the adjusting body (77). The gas permeable openings connect the high pressure chamber (87) with the low pressure chamber (89) and the low pressure chamber can be connected with the interior area of the housing interior.

Description

The invention relates to a silencer for flowing gas, in particular for pulsating flowing exhaust gas of an internal combustion engine, according to the preamble of claim 1.

When an internal combustion engine connected to the exhaust having the muffler has one or more cylinders each having a piston displaceable therein, the or each cylinder emits an exhaust impingement at each full cycle of operation of the cylinder and piston, such that the pressure of the exhaust gas in the exhaust is consequent this surge exhaust gas supply fluctuates. These fluctuations are regular and periodic at constant engine speed and are also referred to as acoustic pressure fluctuations. The frequency of these acoustic pressure fluctuations is proportional to the speed of the engine and the number of cylinders connected to the exhaust.

Further, changes in the speed and output power of the engine cause changes in the average flow rate over a full period or multiple periods of acoustic pressure fluctuations. These changes in the flow rate in turn cause changes in the pressure of the exhaust gas or are associated with such pressure changes. These pressure changes are not periodic and generally slower than the acoustic, more or less periodic pressure fluctuations.

The muffler is particularly suitable for use as part of an exhaust for an internal combustion engine Motor vehicle or possibly another motor vehicle provided and has a passage which is partially or completely shut off with valve means. The valve means have a valve seat arranged in and / or at the passage and an adjustable blocking element. By temporarily, at least partially shutting off the passage, the damping properties of the muffler can be changed and adapted to the flow rate of the exhaust gas. The valve means are provided with actuating means and / or connected to the blocking element depending on the flow rate of the gas supplied to the muffler and / or depending on a present at a certain point, associated with the flow rate pressure or of a pressure difference of the gas automatically to adjust. This pressure or pressure difference is dependent on the flow rate. Such a silencer, which has valve means operable by the exhaust gas itself, is also referred to as a semi-active silencer.

One from the utility model DE 89 08 244 U known muffler has an inlet pipe and two outlet pipes, one of which has a valve seat. This is formed by a widening of the outlet tube in the flow direction widening from the inlet opening of the outlet pipe. The valve means have a, arranged in the interior of the housing corrugated pipe, one end of which is immovably connected to the lockable outlet pipe. The other end of the corrugated pipe is connected by a slidably guided shaft with a serving as a blocking element for shutting off the valve seat valve plate. The corrugated tube is closed at both ends and contains an interior space. This is connected by a control line to the passage of the inlet pipe. The corrugated tube is somewhat springy and thus forms also spring means. If no or little exhaust gas flows into the muffler, the valve plate is pulled by the spring force of the corrugated tube against this and against the valve seat and pressed against the latter. As the flow rate of the exhaust gas increases, the pressure of the exhaust gas in the inlet tube and the corrugated tube increases, so that the latter is extended and lifts the valve plate from the conical valve seat and pushes further into the extension of the outlet tube. If the exhaust gas pressure in the corrugated pipe rises above a certain pressure limit value, that is, the passage of the closable outlet pipe is successively opened more and more with increasing exhaust gas pressure until the valve disk reaches an end position. When the valve disk has been lifted off the valve seat, exhaust gas from the interior of the muffler flows through the inlet opening of the closable outlet pipe against the valve disk, is deflected by the latter and then flows through the annular gap between the inner surface of the outlet pipe and the valve disk. Thereafter, the exhaust gas continues to flow in the longitudinal direction of the exhaust pipe therethrough.

The corrugated pipe is in the utility model DE 89 08 244 U not described in detail. However, known corrugated pipes have a deformable, usually made of thin sheet metal and slightly resilient jacket. The from the DE 89 08 244 U known muffler has, inter alia, the disadvantages that the corrugated tube by the hot, for example, a temperature up to 600 ° C having and also highly stressed exhaust gas, so that the corrugated tube fatigued relatively quickly and has only a short life. Furthermore, solid impurities, such as soot particles, can accumulate inside the corrugated pipe and impair its function. Furthermore, can at accumulate condensate in the corrugated pipe in a cold start and increase the corrosion even more. In addition, the corrugated pipe allows only a relatively small stroke of the valve disk.

The valve disk of the DE 89 08 244 U known silencer is displaced away from the bearing surface of the valve seat in the general flow direction of the exhaust gas flowing through the outlet pipe when opening the closable outlet pipe. The exhaust gas therefore has a high flow velocity when it flows into the outlet pipe, during the deflection through the valve disk and when it flows through said annular gap. This results in the disadvantage that the exhaust gas generates a strong flow noise when flowing around the valve disk. Thus, the sound attenuation of the muffler is deteriorated at high flow rates after the partial opening of the lockable passage. This is particularly the case when the exhaust gas pressure in the corrugated pipe is only relatively little greater than said pressure limit and the valve head remains in an intermediate position in which the pressure force generated by the exhaust compensates for the spring force generated by the corrugated tube and between the inner surface of the Outlet tube and the valve disc existing annular gap is narrow. Even if the valve disk was displaced away from the valve seat at very high exhaust gas flow rates up to its end position, the exhaust gas still has to flow around the valve disk. It should also be noted that a corrugated pipe, as mentioned nicely, allows only a small stroke of the valve disk, so that the latter accordingly can not be moved far away from the valve seat. The described flow around the valve disk in the outlet pipe also has the disadvantage that the valve disk increases the flow resistance and the backpressure caused by the muffler and exhaust.

In the from the DE 89 08 244 U known muffler varies the force generated by the corrugated pipe in the rhythm of the exhaust fumes. This periodic force change at constant speed can cause periodic opening and closing of the valve and rattling noises. This is all the more the case because the inlet opening of the opening into the interior of the corrugated pipe control line is located in the jacket of the inlet pipe, which conducts the exhaust gas into the housing interior of the muffler. The exhaust gas conducted into the corrugated tube through the control line therefore has a pressure which is only equal to the static pressure and thus less than the total pressure of the exhaust gas flowing through the inlet tube. Therefore, in particular, the pressure changes caused by changes in the flow rate are only relatively small. This in turn results in the disadvantage that the spring force generated by the corrugated pipe must be sized small and that caused by the pulsation of the exhaust gas, periodic force changes in relation to the spring force are relatively large.

There are also known mufflers in which the passage of an opening into the interior of the muffler inlet pipe or a completely located in the interior of a muffler, different chambers of this connecting inner tube can be partially blocked with an adjustable locking element.
From the publication DE 195 03 322 A For example, mufflers are known in which a valve disc for shutting off the opening into the housing interior opening of the inlet tube is present. The adjustment means of the muffler serving for adjusting the valve disk comprise a can and a flexible membrane arranged therein, as well as a spring. The Membrane divides the can interior into a high pressure chamber and a low pressure chamber. The high-pressure chamber is connected to a control line which is connected laterally to the intake pipe upstream of the outlet opening of the inlet pipe and outside the muffler housing, or is integrated into the rod which connects the diaphragm to the valve disk. In the high-pressure chamber, therefore, either the pulsating static pressure or the pulsating total pressure of the exhaust gas prevails. The low-pressure chamber is connected to the ambient atmosphere, so that prevails in the low-pressure chamber at least temporarily more or less constant and in particular non-pulsating atmospheric pressure.

The force generated by the membrane and transmitted to the valve plate varies greatly in the rhythm of the exhaust fumes. The exhaust gas flowing through the inlet also exerts a force acting directly on the valve disk. This force also varies with the exhaust stroke and has the same direction as the force exerted by the exhaust gas on the diaphragm. The valves of the DE 195 03 322 A known mufflers therefore have an even greater tendency to rattle in the rhythm of the exhaust fumes than the valve according to the DE 89 08 244 U ,

The can of the adjusting means of the DE 195 03 322 A known muffler is located outside the actual muffler housing and therefore needs additional space that does not serve for the actual sound attenuation. Since the arranged in the can membrane must be very thin and very flexible and can hardly be made of metal, it would also hardly possible because of the high temperatures inside the housing to arrange the can with the membrane inside the housing.

In addition, the arrangement of the box outside the housing results in a considerable risk that a leak occurs in the can or in a control line connecting the latter with the rest of the silencer, and hot exhaust gas escapes. Furthermore, a membrane allows only a small stroke of the valve disk. Furthermore, the gas-tight arrangement of a membrane in a can is complex and expensive. In addition, in the high-pressure chamber of the can solid impurities, such as soot particles, and accumulate condensation in a cold start. In the from the DE 195 03 322 A Known mufflers with the blocking element further - as mentioned - the outlet opening of the inlet tube shut off, so that the available passage cross-sectional area for the effluent from the muffler housing exhaust gas can not be changed with the valve. Furthermore, the blocking element serving to at least partially shut off a passage in the case of the DE 195 03 322 A shifted known muffler when opening in the general flow direction in which the exhaust gas flows through the closable passage. The valve is therefore in the silencer according to the publication DE 195 03 222 A when opening similar to the previously described, from the DE 89 08 244 U known silencer free in many operating conditions only small passage areas, so that the gas generated by flowing through this strong flow noise.

The patent DE 125 837 C discloses a muffler having a housing, an inlet tube and an outlet tube. The latter has two lateral, opposing openings, which can be closed off with two attached to a rod valve plates. A spring engages at one end of the rod to this.

At the other end of the rod eint funnel-shaped projection is attached, which is located in the interior of the housing opposite the outlet opening of the inlet tube. The force exerted by the spring on the rod tends to lift the two valve discs across the outlet tube from the lateral openings of the latter.

When an internal combustion engine is connected to the intake pipe of the muffler and intermittently supplies exhaust gas during operation, the exhaust of the muffler is completely closed by the valve for a certain period of time with each supply of exhaust gas supplied, and then re-opened. The valve therefore generates a rattling noise. When the valve is open, the exhaust gas flows through the two openings of the outlet tube transversely to this in opposite directions in the outlet tube and is then deflected in this sharply. Such a flow causes strong turbulence and noise. These turbulences and noises are exacerbated by the fact that the second valve plate is displaced during opening in relation to the general flow direction in the closable through him opening downstream into the interior of the outlet pipe and there disturbs the flow additionally.

If the engine has several cylinders, as is common in modern engines, would probably be provided for each cylinder a separate silencer, which would be very expensive.

Since the valve is fully closed and re-opened with each exhaust stroke supplied by the engine, the two valve plates become more modern when using a modern one Motors with a high frequency and high speed back and forth. The valve is therefore subjected during operation of a heavy load, which requires a complex and expensive manufacture of the valve of the or each required for an engine silencer. If, during operation, the spring, which is also heavily stressed, should break, the outlet would remain permanently completely closed so that exhaust gas could no longer escape. This could then cause significant further damage to the engine and exhaust.

The patent US 6,427,645 B discloses a silencer whose interior is divided by a partition into a first chamber and a second chamber. The first chamber is connected to the exhaust passage of the cylinder of a two-stroke engine. The second chamber is provided with an outlet. The partition has three openings distributed along a circle. These can be closed with a valve plate. The valve plate is guided with distributed along its circumference, deformable and corrugated guide elements and connected by a rod with a disposed in the second chamber membrane, which acts on a spring. The membrane is attached to the wall of the housing of the muffler and appears according to the hatching of rubber or a rubbery material.

If, during operation in the second chamber, a large pressure prevails and acts on the membrane, the valve plate is pressed against the valve seat formed by a surface of the partition wall and closes off the openings of the partition, so that no exhaust gas can flow out of the first chamber. When the pressure in the second chamber is below a limit decreases, the valve plate is lifted by the force generated by the spring upstream of the partition.

Since the valve is fully closed and reopened in each cycle of the muffler exhausting cylinder of the two-stroke engine, various parts of the valve and in particular the valve plate leading, deformable, corrugated guide elements and above all and serving for moving the valve plate membrane are very strong claimed.

This is all the more the case because the muffler is located directly on the engine and the exhaust gas accordingly flows into the muffler at a very high temperature. The production of such a silencer with a sufficient life is therefore difficult and time-consuming. If the spring should break during operation, the openings in the partition would remain permanently closed, which is analogous to that of the DE 125 837 C known muffler further damage, especially damage to the engine, could have consequences.

The US 6,427,645 also discloses a muffler with a valve having a pivotable flap. The flap is controlled by a cam arranged on the crankshaft of the engine and a bar which scans it.

This muffler has, among other disadvantages, that the said rod from the outside through a passage must be performed in the interior of the muffler, that this rod outside the muffler space claimed and greatly limited the possibilities for the placement of the muffler.

In addition, both are from the US 6 27 645 B known, previously described muffler suitable only for a two-stroke engine. Further, when such an engine has a plurality of cylinders, a separate muffler must be manufactured and assembled for each cylinder, which increases manufacturing and assembly costs.

The invention has for its object to provide a muffler having at least one at least partially shut-off passage and avoids the disadvantages of the known muffler. The muffler should in particular starting from the DE 195 03 322 A allow the blocking element is moved as little as possible by the pulsation of the exhaust gas. Furthermore, it should be possible that the adjusting means are sufficiently resistant to high temperatures and that the adjusting means and in particular their moving parts can be arranged at least substantially and preferably completely within the housing of the muffler. Furthermore, should be avoided as much as possible that accumulate solid impurities and / or condensation and / or other liquids in the connected to the control line chamber of the actuating means. The adjusting means should also allow a large adjustment of the blocking element of the valve. Furthermore, it is to be made possible that the gas flowing after the opening of the closable passage generates only the least possible flow noise and only the lowest possible back pressure. Furthermore, the silencer and in particular its purpose for shutting off and releasing the passage serving valve and actuating means should be robust and durable and a enable trouble-free operation. Furthermore, the muffler and its valve and actuating means should be economical to produce.

This object is achieved by a muffler with the features of claim 1.

Advantageous developments of the muffler will become apparent from the dependent claims.

The silencer according to the invention can be installed, for example, in an exhaust system for a four-stroke engine with several cylinders. The inlet of the silencer according to the invention can then be connected, for example via upstream exhaust parts - such as pipes, a catalyst and possibly still another pre-silencer - with all cylinders or with at least two cylinders of the engine. However, the silencer according to the invention can also be used for a two-stroke engine with only a single cylinder. The muffler may further be arranged relatively far downstream of the engine, so that the exhaust already has a smaller temperature and smaller pressure fluctuations when flowing into the muffler than when flowing out of the engine.

The invention provides, inter alia, the advantage that a pulsation of the exhaust gas causes at most small movements of the blocking element and in particular hardly a rhythmic opening and closing of the valve.

Furthermore, the invention provides the advantage that the limitation of the high-pressure chamber and also the remaining valve means from up to high temperatures of the gas heat resistant and corrosion resistant components can be produced, which ensure a long life and flow-free operation of the valve means. For this purpose, it should be noted that the high-pressure chamber of the actuating means exclusively by dimensionally stable parts, namely by the can wall and the movable arranged in the box actuator, in particular its actuator body, can be limited. The limitation of the high-pressure chamber of the actuating means of the inventive muffler thus requires - unlike many known mufflers - neither a deformable membrane nor a deformable corrugated pipe nor else a deformable component.

Furthermore, the inventive design of the silencer allows the blocking element to move away from the valve seat when opening the valve. This in turn helps to avoid that the exhaust gas generates flow noise and a large back pressure when the valve is open when flowing around the blocking element.

• Fig. 1 einen schematischen Längsschnitt durch einen Schalldämpfer mit sich in der Sperr-Stellung befindenden Ventil- und Stellmitteln,
• Fig. 2 einen Längsschnitt durch die sich in der Sperr-Stellung befindenden Ventil- und Stellmittel in grösserem Massstab,
• Fig. 3 einen zur Fig. 1 analogen Längsschnitt durch den Schalldämpfer, aber mit sich in der Offen-Stellung befindenden Ventil- und Stellmitteln,
• Fig. 4 einen zur Fig. 2 analogen Längsschnitt durch die Ventil- und Stellmittel, wobei diese sich aber wie in Fig. 3 in der Offen-Stellung befinden,
• Fig. 5 eine Schrägansicht einer Variante der Ventil- und Stellmittel, und
• Fig. 6 eine Schrägansicht der in Fig. 5 ersichtlichen Stellmittel, wobei die Dose der Stellmittel aufgebrochen ist.

The subject invention will now be explained with reference to an embodiment shown in the drawings. In the drawings shows:

• Fig. 1 a schematic longitudinal section through a silencer with located in the locked position valve and adjusting means,
• Fig. 2 a longitudinal section through the located in the locked position valve and actuating means on a larger scale,
• Fig. 3 one to Fig. 1 analogous longitudinal section through the muffler, but with it in the open position valve and adjusting means,
• Fig. 4 one to Fig. 2 analogous longitudinal section through the valve and adjusting means, but these as in Fig. 3 in the open position,
• Fig. 5 an oblique view of a variant of the valve and actuating means, and
• Fig. 6 an oblique view of in Fig. 5 apparent adjusting means, wherein the can of the actuating means is broken.

The in the FIGS. 1 and 3 Silencer 1 shown in various operating conditions is intended for use as part of an exhaust for an internal combustion engine. The muffler 1 has a simplified drawn housing 3 with a cross-section example, approximately circular or oval jacket 3a and two arranged at the ends end walls 3b, 3c.

The housing 3 surrounds a housing interior 5 and contains, for example, at least one intermediate wall, namely two extending transversely to the jacket 3 a, attached thereto intermediate walls 7 and 9. These are at least locally permeable to gas, namely perforated, and subdivide the housing interior. 5 in three interior areas 5a, 5b, 5c.

The muffler has an inlet 11 with an inlet pipe 13 projecting from the end wall 3b into the housing interior 5. This penetrates the two, for example Partitions 7 and 9, is attached to the end wall 3b and, for example, even at the intermediate walls 7, 9 and has an opening into the interior region 5c outlet opening 13a and an axis 15. The muffler also has at least two outlets, namely a first outlet 21 with a first outlet tube 23 and a second outlet 25 with a second outlet tube 27. The two outlet tubes 23, 27 protrude from the end wall 3c into the housing interior 3 and penetrate, for example, the intermediate walls 7, 9 so that they extend into extend the interior region 5a. The two outlet pipes 23, 27 are fastened to the end wall 3c and, for example, also to the intermediate walls 7, 9. The first outlet pipe 23 has a permanently open inlet opening 23a at its end situated in the housing interior. The second outlet pipe 27 has an inlet opening 27a at its end situated in the interior of the housing and is provided with valve means 31 therewith, so that the second outlet 25 can at times be closed at least approximately tightly.

The inlet pipe 13 is connected outside the housing 3 or at its end wall 3b in the usual way via other exhaust parts with the internal combustion engine. The two outlet pipes 23, 27 have, for example, pipe sections which protrude from the housing 3 and discharge into the ambient atmosphere, or are still connected to the ambient atmosphere via additional pipes.

The valve means 31 have a in different operating conditions in the Figures 2 and 4 apparent valve 33 which is connected and / or provided with serving for its actuation means 35. The valve means 31 and the valve 33 and the adjusting means 35th have a common housing, which is referred to below as a box 41. The can 41 has a can axis 43, and a dimensionally stable can wall 44. This has a can axis 43 surrounding, generally cylindrical, circular in cross-section can jacket 45 and two end walls 47, 49, each of which is fixedly connected to the ends of the jacket 45 ,

The end wall 47 has at its outer edge a bent flange with a parallel to the can jacket, adjacent thereto portion and at least one annular stiffening rib and / or -nut or the like. The end wall 47 is, for example, compact and hole-free. The other end wall 49 is annular and has an annular, planar portion 49a and at the inner edge of a collar 49b, which is bent away from the can and the other end wall 47 outwardly and / or angled, abuts the outer surface of the second outlet tube 27 and attached to the latter. The can 41 is thereby firmly connected to the second outlet tube 27 and, for example, still attached to the intermediate wall 7 and fixed, but could also be at a distance from the latter. The can is located at least in part, namely completely in the housing interior. 5

The innermost annular portion of the flat portion 49a of the end wall 49 of the can 41 forms a valve seat 49c which has an annular, flat seat surface on its side facing the can interior 57. The valve seat 49 c is arranged directly at the inlet opening of the closable passage of the second outlet in and / or at this passage, so that the valve seat limits this inlet opening and the inner edge of the annular bearing surface of the valve seat this Enclosing opening encloses. For example, the outer valve-seat-surrounding annular portion of the planar portion 49a of the end wall 49 is still provided with a few circumferentially-spaced gas passage holes 49d opening into the interior portion 57c of the can. Of course, the can axis 43 also forms the axis of the valve seat 49c and coincides at least approximately with the axis of the straight end portion of the second outlet tube 27 connected to the can. It should also be noted that in the manufacture of the muffler preferably the whole box is made with the valve seat and the can then connected together with the valve seat with the outlet pipe 27 and installed in the muffler, so just the can axis exactly with the axis of the valve seat coincides, while the axis of the outlet pipe may be due to manufacturing inaccuracies inclined a little against the can axis and / or offset.

The can 41 includes two intermediate walls 53, 55. Each of them has a flat disc perpendicular to the can axis 43 and at the edge a collar 53a or 55a projecting from the disc on its side facing away from the valve seat, on the inner surface of the can jacket 45th is present and attached to this. At least the closer to the valve seat 49c located intermediate wall 55 is connected at least to some extent or completely sealed to the can jacket. The intermediate wall 53 farther from the valve seat 49c is provided with a ring of gas passage holes 53b and, accordingly, gas permeable. The can 41 encloses a can interior 57, which is divided by the intermediate walls 53, 55 into three interior regions 57a, 57b, 57c. The furthest away from the valve seat interior portion 57 a and the middle The interior portion 57b is connected to each other through the gas passage holes 53b, while the center interior portion 57b and the interior portion 57c adjacent to the valve seat 49c are at least slightly separated from each other.

The can jacket 45 has an annular portion near each of its both ends, which is provided with a plurality of circumferentially distributed gas passage holes 45a and 45b, respectively. The gas passage holes 45a open into the inner space portion 57a, while the gas passage holes 45b open into the inner space portion 57c of the can. The can jacket further has an opening 45c arranged at a circumferential location between the gas passage holes 45a, 45b, which opens into the central interior area 57b provided between the two partition walls 53, 55. The opening 45c serves as a control line connection and is at its edge firmly and tightly connected to a consisting of a bent pipe control line 59. The control line 59 projects through a hole in the jacket of the inlet pipe 13 into the passage defined by it, is fixed to the said hole in the jacket of the inlet pipe and is at least somewhat tightly connected thereto and has a curved section with a straight line in the inlet pipe. at least approximately parallel to the axis 15 and approximately coaxial end portion 59a. This has an inlet opening 59b which lies in a plane at least approximately perpendicular to the axis 15 of the inlet tube, is approximately concentric with the inlet tube and faces the region of the inlet tube located upstream of the control line. The outer diameter of the control line 59 is significantly smaller than the inner diameter of the inlet tube 13. Between the inner surface of the inlet tube 13 and the straight, parallel to the axis 15 end portion 59a of the control line is therefore an annular, the end portion 59a without interruption enclosing, free area of the passage available. The cross-sectional area of the passage of the control line is significantly smaller than the cross-sectional area of the passage of the inlet tube and is preferably at most 50%, preferably at least 5% and for example approximately 15% to 35% of the latter cross-sectional area.

The inlet opening 59b of the control line 59 is located in the inlet tube 13, of course, upstream of its outlet opening 13a and has a distance of at least equal to 1 times and preferably at least equal to 3 times the inner diameter of the inlet tube 13.

In the central interior region 57b of the box 41, a socket 61 coaxial sleeve 61 is arranged immovably. The sleeve protrudes into central holes of the two partitions 53 and 55 and is at least reasonably tightly attached thereto. The bushing has a through hole 61a coaxial with the can axis.

The valve 33 has an adjustable, namely parallel to the can axis 43 slidable locking element 65 for temporary, at least approximately tight shut-off of the passage of the valve seat 49c and the second outlet pipe 27 from. The blocking element 65 has a valve body 67, namely a plate-shaped valve plate 67, which essentially consists of a flat, circular, dimensionally stable, metallic plate or disk, has a hole in the center and is fastened to a rod 69 by a screw 71 penetrating the same , The rod 69 penetrates the hole 61 a of the sleeve 61 and is slidably guided in the socket with a small amount of play. The valve disk is provided on its side facing the valve seat 49c at its outer edge with an annular damping element 73, with which the valve disk in the in the Figures 1 and 2 shown blocking position of the valve rests on the valve seat. The valve disk is provided on its side facing away from the valve seat with an annular damping element 75, which encloses the end of the rod 69 and in the in the 3 and 4 shown open position of the valve to the intermediate wall 55 and / or on the sleeve 61 is applied. The damping element 75 forms together with the intermediate wall 55 and / or the sleeve 61 stop means which define the open position of the valve disk. The two damping elements 73, 75 are for example a little deformable, consist for example of pieces of wire, each depending on one or more wire mesh layer (s) or of a non-woven or the like formed from pieces of wire and are for example by some point-like welds on the disc of Attached valve disk.

The valve body or valve disk 67 has on its side facing away from the valve seat a first surface 67a and on its side facing the valve seat a second surface 67b. The outer diameter of the flat bearing surface of the valve seat 49c and the diameter of the valve plate 67 are significantly smaller than the inner diameter of the can jacket 45 and are preferably at most 90% and, for example, about 70% to 80% of the inner diameter of the can jacket. Accordingly, in all positions of the valve disk between the peripheral edge and the can jacket a free, annular, fairly wide area of the can interior is present. The sum of Cross sectional areas of the gas passage holes 49b and 49c of the can jacket 45 and the end wall 49 of the can 41 are substantially larger than the cross sectional area of the passage of the second outlet pipe 27.

The adjusting means 35 have a dimensionally stable, displaceable in the can 41 along the doses axis actuator. This has as its main component a dimensionally stable adjusting body 77, namely a circular, at least substantially planar metallic adjusting plate or adjusting disk 77. The adjusting body 77 is slidably disposed in the inner space portion 57a of the can 41, has a hole in the center, and is fixed thereto at the end portion of the rod 69 projecting into the inner space portion 57a. The adjusting body 77 has on its side facing the valve seat, a first surface 77a and on its side facing away from the valve seat, a second surface 77b. The diameter of the adjusting body 77 is a little, preferably at least 0.5 mm, and preferably at most 3 mm and for example about 1 mm to 2 mm, smaller than the inner diameter of the can jacket 45, so that between the latter and the actuating body a free, gas-permeable Ring gap 79 is present, which encloses the actuator body completely and without interruption and whose width according to the specified diameter differences preferably at least 0.25 mm, preferably at most 1.5 mm and, for example, about 0.5 mm to 1 mm. The cross-sectional area of the annular gap 79 is preferably smaller than the passage cross-sectional area of the control line 59, and is preferably at most 60% and more preferably at most 50% of the passage cross-sectional area of the control line. The inner diameter of the can jacket 45 and the diameter of the actuating body 77 are also dimensioned such that the passage area of the annular gap 79 preferably is at most 15%, preferably at least 1% and, for example, about 3% to 10% of the entire cross-sectional area of the actuator body containing portion of the can interior 57.

At the side facing away from the valve seat of the adjusting disk, a sleeve 81 is attached. This is at least for the most part cylindrical and circular in cross section and open at its end facing away from the adjusting disc. The outer diameter of the cylindrical body of the sleeve is significantly smaller than the inner diameter of the can jacket 45, and is at most 70%, at least 30% and, for example, about 45% to 55% of the inner diameter of the can jacket. The adjusting means further comprise spring means with a spring 83 which is designed as a pressure coil spring. One end of the spring 83 abuts against the end wall 47 of the can 41 and is centered by an elevation of the end wall 47 projecting toward the can interior. The other end of the spring engages the adjusting body 77. For example, the spring protrudes into the sleeve 81 and has an outer diameter that is slightly smaller than the inner diameter of the sleeve 81. Instead, the spring could have a slightly larger diameter than the sleeve and surround it with play.

The plate- or disc-shaped actuator body 77 divides the interior portion 57a of the can containing it and the interior portion 57b of the can connected thereto through the gas passage holes 53b into two chambers, hereinafter referred to as first chamber 87 or high-pressure chamber 87 and second chamber 89 or Low-pressure chamber 89 may be referred to. The high-pressure chamber 87 is penetrated through the inner space portion 57b and through the gas passage holes 53b formed with this connected, located on the valve seat side facing the adjusting body 77 located portion of the interior region 57a. The high-pressure chamber 87 is accordingly connected to the inlet pipe 13 through the control line 59. The low-pressure chamber 89 is located between the end wall 47 and the adjusting body 77 and is connected through the gas passage holes 45a of the can jacket 45 with the box 41 containing and surrounding interior area 5a of the muffler.

The described parts of the muffler are all made of metallic materials which are heat resistant up to temperatures of at least 600 ° C and for example up to at least 700 ° C or even to at least 800 ° C. The spring 83 is made of, for example, the nickel base alloy known by the trade name Inconel. The remaining parts are made of steel, for example. The firmly interconnected, metallic parts of the muffler are welded together, for example.

In the following, the operation and some associated properties of the muffler 1 will be explained. The combustion engine connected to the silencer supplies the silencer with pulsating, hot gas, ie exhaust, during operation. The flow rate and the pressure of the exhaust gas are variable and usually increase with increasing speed and with increasing power of the engine. The exhaust gas flowing through the exhaust and the muffler associated therewith, generated at a relatively low speed and correspondingly small flow rate, especially by the pulsation of the exhaust gas flow. At higher speeds and larger flow rates then the exhaust gas at Flowing through the passages created flow noise important and dominant.

When the internal combustion engine is stationary and if it supplies exhaust gas to the silencer after starting only with a small flow rate, the valve body or valve disk 67 of the valve 33 is in the blocking position and blocks the passage of the second outlet 25 at least approximately tightly, so that Exhaust gas can flow out of the housing interior 5 practically only through the first outlet 21. This results in a particularly good damping of the noise generated by the pulsation of the exhaust gas flow.

When the flow rate of the exhaust gas supplied to the muffler increases and exceeds a certain opening limit value, the valve body 67 of the valve is automatically displaced by the adjusting means 35 in the open position and releases the passage of the second outlet 25, so that Both outlets 21, 25 exhaust gas can flow out of the housing interior. This produces less flow noise and a lower back pressure than if only the first outlet were open. When the flow rate of exhaust gas supplied to the muffler drops below a lock limit, the valve disk is returned to the lock position. In the FIGS. 1 and 3 are indicated by arrows some in the blocking position or in the open position resulting gas flows.

After this general operating description, some details of the function of the valve will now be explained in more detail. It should first be noted that the exhaust gas at least partially or completely open Valve in a general flow direction through the passage of the second outlet 25 flows. This general flow direction is at the valve seat 49c and in the subsequent thereto portion of the passage parallel to the common axis of the can, the valve seat and the subsequent thereto passage portion. The flat bearing surface of the valve seat is thus facing a space region which is upstream of the valve seat with respect to the general flow direction. This space area, which faces the bearing surface of the valve seat and adjoins the bearing surface, is of course formed by the interior portion 57c of the can passing through the gas passage holes 45b with the interior area 5a surrounding and surrounding the can and, for example, through the gas passage holes 49d and the gas-permeable wall 7 is connected to the inner space portion 5b of the housing inner space 5.

The spring 83 is biased and operates under all operating conditions - i. with the engine stopped and with the engine running and with all positions of the valve body or valve disc 67 - a spring force on the actuator body 77, i. the adjusting plate or the adjusting disk 77. This spring force is transmitted through the rod 69 to the valve body or valve plate 67 and strives to press this against the valve seat 49c.

If the internal combustion engine supplies exhaust gas to the muffler, this can exert additional forces on the control body 77 and from there via the rod 69 on the valve body or valve disk 67 as well as directly on the latter in a manner to be described in more detail.

When the blocking element 65 in the in the Figures 1 and 2 The exhaust gas flowing into the interior region 57c of the can 41 exerts a pressure force directed against the valve seat on the first surface 67a of the valve disk 67 which adjoins the interior region 57c. The second outlet tube 27 then contains gas, ie, air and / or exhaust, which has approximately ambient air pressure and exerts a compressive force on that portion of the second surface of the valve disc 67b that is within, ie, not within, the bearing surface of the valve seat 49c Bearing surface rests and adjacent to the located downstream of the valve seat portion of the passage, which is enclosed by the second outlet tube 27 and the collar 49 b. Since the gas pressure in the blocking position in the interior region 57c is greater than in the second outlet pipe 27 and since the exhaust gas present in the interior region 57c also acts on a larger surface of the valve disk than the gas having the ambient air pressure in the second outlet pipe, this exerts on the valve disk attacking gas on this total directed against the valve seat force on the valve disk. This force exerted directly by the gas on the valve plate is referred to below as a holding force and adds up to the same directional spring force.

During operation of the internal combustion engine, a large part-and for the most part-of the exhaust gas supplied to the inlet 11 flows through the outlet opening 13a of the inlet pipe 13 into the free areas of the housing interior 5. However, exhaust gas also flows from the inlet pipe 13 through the control line 59 in the high-pressure chamber 87 of the can 41, then through the annular gap 79 in the low pressure chamber 89 of the can and through the Gas passage holes 45a out of the can into the surrounding interior area 5a of the muffler. Above the annular gap 79, a pressure gradient arises. The end section 59a of the control line arranged in the interior of the inlet tube 13 acts similarly as a pitot tube as a pressure probe and detects the total pressure present at the inlet opening 59b of the control line, ie the sum of the static pressure and dynamic pressure of the exhaust gas flowing through the inlet tube. This pressure of the exhaust gas is transferred into the first chamber or high-pressure chamber 87 of the can 41. The exhaust gas in the high-pressure chamber 87 has a greater pressure than the exhaust gas in the low-pressure chamber 89, in which the pressure is approximately the same size as in the interior region 5a of the housing. The plate-shaped or disk-shaped adjusting body 77 serves as a pressure force transducer for the exhaust gas flowing through the can. The exhaust gas exerts in the two chambers 87, 89 opposing forces on the two surfaces 77a, 77b of the actuating body 77, which result in a total directed away from the valve seat and the spring force opposite force. This force exerted by the exhaust gas on the adjusting disk is referred to below as the opening force.

Here are some remarks to the pressure changes of the exhaust gas to be inserted.

The muffler 1 is - as already mentioned in the introduction - preferably connected to two or more cylinders of the engine and arranged relatively far downstream of the engine in the exhaust, so that caused by the stosweise exhaust gas supply of the engine, acoustic, at constant speed periodic pressure fluctuations when the exhaust gas flows into the Control line 59 are already somewhat balanced and smoothed.

The cross-sectional area of the can interior 57 and in particular of the region of the high-pressure chamber 87 adjoining the control body 77 is substantially greater than the passage cross-sectional area of the control line. This results in an additional compensation of the pressure fluctuations caused by the stoßweise exhaust gas supply. Furthermore, the pulsation of the exhaust gas on both sides of the actuator causes approximately synchronous and almost equal pressure fluctuations. The forces exerted by these acoustic pressure fluctuations on the two sides of the actuator body compensate each other therefore at least largely. Since the pressure probe formed by the control line 59 determines the total pressure of the exhaust gas at the inlet opening of the control line in the inlet, the dependent on the average flow rate pressure difference between the high-pressure chamber 87 and the low-pressure chamber 89 is relatively large. This allows the spring 83 to be sized to produce a relatively large spring force. For these reasons, the actuating means move the blocking element 65 of the valve almost exclusively as a function of the pressure associated with the average flow rate. In contrast, the valve is not or at least practically not opened and closed by the acoustic pressure fluctuations caused by the stosweise exhaust gas supply.

When the internal combustion engine supplies exhaust gas to the muffler only at a small flow rate after starting, and the opening force exerted on the actuator by the exhaust gas is smaller than the sum of the spring force and the holding force, the valve disk remains in the lock position.

As the flow rate increases, the opening force applied to the actuator also increases and, upon reaching the opening limit, becomes equal to the sum of the spring force and the holding force. With an increase in the flow rate above the opening limit value, the opening force exerted by the exhaust gas on the adjusting body shifts the adjusting body 77 and the associated valve disk 67 away from the valve seat 49c. The displacement of the valve disk takes place counter to that after lifting the valve disk from the valve seat resulting, general flow direction of the exhaust gas in the passage of the second outlet 25. Once the valve disk has been lifted a little from the valve seat, exhaust gas flows from the housing interior 5 through the interior area 57c of the can interior 57 in and through the passage of the second outlet tube 27 and thereafter into the ambient atmosphere. In this case, the gas pressure in the housing interior and in particular the gas pressure acting on the first surface 67a of the valve disk 67 decreases. Furthermore, and above all, the holding force exerted by the gas on the valve disk decreases at least approximately to zero. By contrast, the difference between the pressures acting on the two surfaces 77a, 77b of the adjusting body and the opening force acting on the adjusting body are only slightly changed when the valve is opened. The consisting of the sum of spring force and holding force, directed against the valve seat force therefore decreases almost abruptly when lifting the valve disk from the valve seat and is much smaller than the opening force. Even if the flow rate only slightly exceeds the opening limit value, the valve disk is therefore displaced relatively far from the valve seat and, even at small excesses of the opening limit value, arrives abruptly in the position determined by the stop means, into the FIGS. 3 and 4 shown open position.

When the valve is in the open position, the exhaust gas exerts virtually no force on the valve disk. If the flow rate of the exhaust gas now decreases, the valve remains open until the force exerted by the exhaust gas on the actuator body opening force is smaller than that in the open position exerted by the spring on the actuator body spring force. As the flow rate decreases further, the spring displaces the actuator body and the valve disk against the valve seat. If the flow rate of the exhaust gas supplied to the muffler drops to the blocking limit value, the valve disk again rests on the valve seat and blocks the second outlet pipe. The gas then exerts a holding force on the valve disk, which presses the latter in addition to the spring force against the valve seat. The flowrate cut-off limit is slightly different from the opening threshold, namely a little smaller than this. The displacement of the valve disk of the in the FIGS. 3, 4 shown open position in the in the FIGS. 1, 2 Although shown blocking position requires a slightly larger change in the flow rate and the exhaust pressure than the reverse displacement of the valve disk. Since the exhaust gas flowing into the second outlet pipe 27 at the valve seat has a general flow direction at the valve seat and at the beginning of the second outlet pipe, which has the same direction as the displacement of the valve disk when moving into the locked position, but also requires the displacement of the valve disk of FIG the open position in the locked position only relatively small changes in the flow rate and the exhaust pressure. In addition, the reduction of the flow rate often occurs during a braking operation of the motor vehicle, wherein the valve disc then also jumped from the open to the locked position.

The valve is usually either completely closed or completely open. When the valve is at least partially open, and in particular when the valve disc in the in the FIGS. 3, 4 drawn open position, the exhaust gas from the box 41 surrounding portion of the housing interior 9 through the gas passage holes 45b and 49d and the gas-permeable partition 7 in the interior portion 57c of the can and then the valve seat with virtually no obstruction by the valve plate 67 in to flow in the passage of the second outlet pipe 27. The gas flow generated accordingly when passing the valve seat and no strong flow noise. It should also be expressly pointed out that, according to the previous description, both the holding force exerted by the gas directly on the valve disk and the opening force exerted by the gas on the actuator body serve to adjust the valve disk and that the valve disk accordingly also acts as part of the actuating means ,

The existing between the can jacket 45 and the actuator body 77 annular gap 79 is wider than the radial clearance of the rod 69 in the sleeve 61 and ensures that the actuator body is never jammed even at high temperatures. The damping elements 73 and 75 prevent the valve disk rattling in the locked position or open position due to vibrations of the muffler. The damping element 73 also results in the blocking position of the valve disk a certain sealing effect. It should be noted that the rod 69 with game leading bush 69 may also have at least one annular damping element of a wire mesh or wire fleece or the like. Incidentally, the can and the spring are dimensioned such that the valve disk is displaced by a relatively large distance when the valve is actuated, which is preferably at least 25% and, for example, at least 50% of the clear width of the second outlet pipe 27.

The gas flowing through the annular gap 79 into the low-pressure chamber 89 could generate possibly audible gas oscillations therein. The sleeve 81 divides the free interior of the low-pressure chamber, counteracts the generation of gas oscillations and shifts the frequency of possibly still generated vibrations up in the inaudible range. The valve is also robust, heat resistant to high temperatures and durable and can be inexpensively manufactured and installed in the muffler.

The exhaust gas may possibly transport soot particles and / or other solid and / or liquid contaminants into the can 41 when using the muffler. In particular, there is also the possibility that condensate forms during a cold start and gets into the can. As described, during operation, exhaust gas from the high pressure chamber 87 of the can flows through the annular gap 79 into and out of the low pressure chamber 89 of the can. This exhaust gas flowing through the can can blow out of the can again solid and liquid contaminants entering the can, thus contributing to the avoidance of disturbances.

The FIGS. 5 and 6 schematically show parts of another muffler, the only schematically indicated in phantom inlet pipe 113 with an axis 115 and two Outlet tubes, of which only the second outlet tube 127 is drawn. This has an example circular inlet opening 127 a, which lies in a plane perpendicular to the axis 129 of the outlet pipe 127 level. The two tubes 113, 127 and the not shown, first outlet tube may be arranged, for example, more or less similar, as the corresponding tubes in the FIGS. 1 to 4 shown silencer. 1

The FIGS. 5, 6 show valve means 131, which in the FIGS. 1 to 4 replace apparent valve means 31 and have a valve 133. The valve means 131 are provided with adjusting means 135 and / or connected. The adjusting means 135 have a can 141 with a metallic can wall 145. This has an end wall 145a, one of these opposite rear wall 145b, two opposing side walls 145c, of which in Fig. 6 one is broken away, and one side wall 145d. The walls 145a, 145c, 145d are substantially planar while the back wall 145b is bent. The end wall 145a has a circular opening 145e serving as a control line terminal. The can 141 is substantially open on its side facing away from the side wall 145d and has an opening therein which forms a gas passage hole 145f which is more or less divided into two parts by the outlet tube 127. Attached to the can wall is an extension 149 which projects away from the side of the can facing away from the side wall 145d and has a plate-shaped, generally flat body which is parallel to the end wall and approximately in the same plane as the latter. The end of the latter forming the inlet opening 127a of the second outlet tube 127 protrudes into an opening of the extension 149, which in part passes through an on the non-visible side of the extension of this widening collar is limited. The outlet tube 127 is fixedly connected to the can wall 145 and the extension 149, namely welded to the rear wall 145b of the can wall and to the extension 149. The axis 129 of the outlet tube 127 coincides approximately or exactly with the axis which is defined by the opening of the extension 149. The area of the extension enclosing this opening serves as a valve seat 149c. This has on the side facing away from the collar a flat, perpendicular to the axis of the opening of the extension seat. The can wall is provided near its connection to the extension 149 with two eyes 153 or firmly connected. These have an incision in which a bearing pin 155 is fixed, which defines a pivot axis 156. The can 141 includes a nozzle interior 157. The pivot axis 156 is located approximately at an edge of the can interior and / or slightly outside thereof approximately in the plane defined by the valve seat 149c between the port 145e and the valve seat 149c. The pivot axis is further parallel to the flat seat surface of the valve seat 149c and perpendicular to the axis of the opening of the extension 149, but offset from this axis.

A control line 159 has a fixed and tightly connected at the opening 145e of the can end wall 145a, and a located in the inlet pipe 113, approximately to the axis 115 of the inlet pipe coaxial end portion 159a with an inlet opening 159b. The latter can be similarly arranged and dimensioned as in the FIGS. 1 and 3 illustrated control line 59.

The valve 133 has an adjustable blocking element 165 with a plate-shaped valve body 167 as Valve flap is formed, which is also referred to below with 167 and is pivotable about the pivot axis 156. The valve flap has a circular main portion, which is connected by a projection 167a fixed to a bearing pin 155 mounted about this pivotable hub 169. The hub is hollow and has a cylindrical shell 169a and two end walls 169b. The valve body or the valve flap 167 consists for the most part of a dimensionally stable metallic plate, on the valve seat 149c side facing an annular, slightly deformable damping element 173 is attached. This is for example similar to the described damping elements 73, 75 formed of pieces of wire and is located on the valve seat with the valve closed.

The adjusting means 135 have a dimensionally stable actuator. This has as a main component a dimensionally stable actuating body 177, which consists of a substantially square-shaped, flat plate, at one of its edges on the jacket 169a of the hub 169 attached, namely welded, and about the pivot axis 156 is pivotally and hereinafter also as a control plate or valve 177 is designated. The valve is at least substantially in the can interior 157. Between the edges of the valve, which are facing the coaxial with the pivot axis 156 curved rear wall 145b and the two side walls 145c of the can, and said walls of the can is a free, gas-permeable gap 179 available. This gap 179 thus extends along three edges of the square adjusting cap and is accordingly angular and more or less U-shaped or C-shaped.

The hub 169 facing edge of the flap 177 is, for example, only over part of its length, For example, only at two spaced apart fastening sections, welded to the coat of the scar. Between the remaining, unshielded sections of said edge of the valve and the hub may then possibly also still narrow, gas-permeable column may be present. Furthermore, there is also a gap between the pivotable hub and the edge of the end wall 145a facing the same.

The parts of the gap 179 extending along three edges of the valve may have similar widths as the gap 79 in FIG FIGS. 1 to 4 illustrated adjusting means. Further, the gap 179 - optionally together with the gaps between the hub and the edge of the adjusting flap facing it - a similar area compared to the cross-sectional area of the can interior. 157, as indicated for the annular gap 79. The cross-sectional area of the can interior 157 is measured in a section plane radial to the pivot axis.

The hollow hub includes a spring 183, namely a helical torsion spring enclosing the bearing pin 155. The one, not visible end of the spring 183 is bent inwardly, protrudes into a hole of the bearing pin 155 and is thereby unschwenkbar connected to the bearing pin and the can wall. The other, in the FIGS. 5 and 6 visible end of the spring is bent outwardly and protrudes through a hole in the cylindrical shell 169a of the hub, so acts on the hub 169 and exerts a torque on this, which tends to push the valve flap against the valve seat 149c.

The actuating body 167 or the butterfly valve 167 subdivides the can interior containing it into a first chamber 187 or high-pressure chamber 187 and into a second chamber 189 or low-pressure chamber 189. The high-pressure chamber 187 adjoins the opening 145e at the control line 159 opens into the can interior. The low-pressure chamber 189 is connected through the gas passage holes 145f of the can 41 to the surrounding portion of the interior of the muffler.

When an internal combustion engine, the intake pipe 113 in the in the FIGS. 5 and 6 Indirectly indicated by arrows, a portion of this exhaust gas flows through the control line 159 into the high-pressure chamber 187 of the can and through the gap 179 as well as possibly between the hub 169 and the edge of the valve facing it into the low-pressure chamber can. Thereafter, this exhaust gas flows out of the can through the gas passage hole 145f thereof into an area of the remaining interior of the muffler adjacent to the can. When exhaust gas is supplied, a pressure gradient arises above the valve. This exerts a force on the valve. This force and the resulting torque endeavor to pivot the valve flap away from the valve seat.

If no or little exhaust gas is supplied to the inlet pipe 159, the valve flap of the blocking element 165 rests on the valve seat 149c and closes the second outlet pipe at least approximately tightly. When the flow rate and the pressure of the exhaust gas supplied increase and the force exerted by the gas on the valve exceeds an opening limit, the butterfly valve 177 in the in Fig. 6 vorschwenkt indicated by an arrow 191 direction. As a result, the valve flap in the pivoted by the arrow 193 direction and lifted off the valve seat. Thereby, the valve is opened so that exhaust gas can flow out of the muffler through the second exhaust pipe 127. The butterfly valve and the valve flap, for example, have been pivoted when opening the valve until the valve 177 is present at the second outlet pipe 127, so that the latter also serves as a stop.

As far as nothing else was previously written, the in the FIGS. 5 and 6 apparent valve means 131 having a silencer be similar and work similarly, as the muffler 1 with the basis of the FIGS. 1 to 4 described valve means 31.

The two described mufflers and their valve can still be changed in various ways. For example, features of the two in the FIGS. 1 to 6 valve means and adjusting means shown are combined in various ways in a slightly modified form if necessary. For example, the gas passage holes 45a could be replaced with a single large hole or the gas passage hole 145f through a plurality of holes.

Furthermore, one could arrange more than two partitions 7, 9 or only one or no intermediate wall in the housing interior. In addition, the valve seat could be formed directly on the second outlet tube 27 and 127 and consist together with the latter of a one-piece body. It should then be ensured during manufacture that the axis of the valve seat forming tube or pipe section with respect to the can and the adjustable locking element has exactly the desired position and direction. Furthermore, the Valve seat instead of a flat bearing surface have a conical bearing surface which tapers downstream with respect to the general flow direction of the exhaust gas and as the bearing surfaces of the in the FIGS. 1 to 6 drawn valves facing a located upstream of the valve seat space area.

Furthermore, the intermediate wall 55 or even the intermediate wall 53 of the can 41 could be formed as the end wall of the can, molding and / or securing the valve seat to the second outlet tube and then securing the can to the second outlet tube and / or the valve seat with gas permeable attachment means. For example, these fasteners could include some posts distributed around the can axis and the valve seat, with gas passage holes between them. The box would then be at a distance from the valve seat, so that its support surface would directly adjoin a free interior region of the housing interior. The can could possibly protrude slightly from the housing at its end facing away from the valve set. The adjusting body 77 could instead of a relatively thin plate or disc consist of a thicker piston in the axial direction.

At least one additional, permanently open and / or at least one additional outlet, which can be shut off with a valve, could possibly additionally be provided in addition to a permanently open outlet and an outlet which can be shut off with a valve.

The dimensionally stable plate of the valve body and / or the adjusting body could instead consist of a metallic material made of ceramic.

In addition, completely arranged in the interior of the housing connecting and / or inner tubes could be present, which connect different interior areas of the muffler together. It would then also be possible to arrange a valve instead of the valve used to shut off an outlet or in addition to such a valve, in order to block an internal passageway which interconnects various interior areas of a housing of a muffler, namely, for example, its inlet opening.

Claims (14)

1. Muffler for flowing gas, in particular for pulsed-flow exhaust gas of an internal combustion engine, comprising a housing (3) enclosing a housing interior (5), at least one passage for the passage of gas and valve means (31, 131) which have a valve seat (49c, 149c) arranged in and/or on the passage or in and/or on at least one of the passages and a blocking element (65, 165) which is adjustable by adjusting means (35, 135), rests on a contact surface of the valve seat (49c, 149c) in a blocking position and then at least partly blocks the passage, the adjusting means (35, 135) having a box (41, 141) with a box wall (44, 145) and having a box interior (57, 157) enclosed by said box wall, an adjusting body (77, 177) which is moveable in the latter and connected to the blocking element (65,165) and divides the box interior (57, 157) into a high-pressure chamber (87, 187) and a low-pressure chamber (89, 189), and spring means for generating a spring force which tends to move the blocking element (65, 165) towards the valve seat (49c, 149c), a control line (59, 159) being present in order to feed gas to the high-pressure chamber (87, 187) for exerting on the adjusting body (77, 177) a force which opposes the spring force, characterized in that a gas-permeable gap (79, 179) which connects the high-pressure chamber (87, 187) to the low-pressure chamber (89, 189) is present between the box wall (44, 145) and the adjusting body (77, 177), and in that the low-pressure chamber (89, 189) is connected to an interior region (5a) of the housing interior (5).
2. Muffler according to Claim 1, characterized in that the passage and the valve means (31, 131) are formed for passing gas in a general flow direction through the passage during operation and when the passage is opened, and in that the blocking element (65, 165) can be moved upstream away from the valve seat (49c, 149c) for opening the passage in relation to said general flow direction.
3. Muffler according to Claim 1 or 2, characterized in that it has at least two outlets (21, 23), in that each outlet (21, 23) has a passage leading out of the housing interior (5), in that at least one of these passages is permanently opened and in that at least one of these passages forms the or a passage which can be at least partly blocked by the valve means (31, 131).
4. Muffler according to any of Claims 1 to 3, characterized in that it has an outlet orifice (13a) opening into the housing interior (5) and in that the control line (59, 159) has an inlet orifice (59b, 159b) which is located upstream of the outlet orifice (13a, 113a) of the inlet tube (13, 113) in the passage of the latter, faces a region of the inlet tube (13, 113) which is present upstream of it, and has an area, measured transversely to the inlet tube (13, 113), which is smaller than the cross-sectional area of the passage of the inlet tube (13, 113).
5. Muffler according to any of Claims 1 to 4, characterized in that the box (44, 141) is arranged at least partly and preferably completely in the housing interior (5) and in that said interior region (5a) of the muffler interior (5) to which the low-pressure chamber (89, 189) is connected bounds the box wall (45, 145) and is connected to the low-pressure chamber (89, 189) via at least one gas port (45a, 145f) present in said box wall.
6. Muffler according to any of Claims 1 to 5, characterized in that the box wall (44, 145) has an inner surface, in that the adjusting body (77, 177) has a stable shape and has an edge facing the inner surface of the box wall (44, 145) and in that the gap (79, 179) extends without interruption along the entire edge of the adjusting body (77, 177), which edge faces the inner surface of the box wall (44, 145).
7. Muffler according to any of Claims 1 to 6, characterized in that the box (41) has an axis (43) and a box casing (45) enclosing said axis, in that the blocking element (65) and the adjusting body (77) are rigidly connected to one another and are displaceable along the axis (43) of the box (41) and in that the gas-permeable gap is an annular gap (79) and encloses the blocking body (77) completely and without interruption.
8. Muffler according to Claim 7, characterized in that at least one section of the box casing (45) which encloses the adjusting body (77) is cylindrical and is circular in cross-section and in that a sleeve (81) which projects into the low-pressure chamber (89) and is cylindrical at least for the most part and is circular in cross-section and has an external diameter which is not more than 70% and at least 30% of the internal diameter of that section of the box casing (45) which encloses the adjusting body (77) and the sleeve (81) is fixed to the adjusting body (77).
9. Muffler according to Claim 7 or 8, characterized in that the box (41) is firmly connected to the valve seat (49c) and/or forms said valve seat and in that the box casing (45) has a casing section which is provided with gas ports (45b) and encloses an interior region (57c) of the box (41), in which interior region the valve disc (67) is displaceable.
10. Muffler according to any of Claims 1 to 6, characterized in that the blocking element (165) and the adjusting body (177) are rigidly connected to one another and are pivotable about a common axis of rotation (156).
11. Muffler according to Claim 10, characterized in that the axis of rotation (156) is arranged approximately at an edge of the box interior (145) and/or outside the latter.
12. Muffler according to any of Claims 1 to 11, characterized in that the blocking element (65, 165) has a plate of stable shape and a damping element (73, 173) which is held thereon and with which the blocking element (65, 165) rests on the valve seat (49c, 149c) in the blocking position, the damping element (73, 173) preferably being formed from wire pieces.
13. Muffler according to any of Claims 1 to 12, characterized in that the contact surface of the valve seat (49c, 149c) is flat and is arranged perpendicular to an axis (43, 129) defined by the blockable passage and directly at the inlet orifice of the blockable passage and encloses said inlet orifice.
14. Muffler according to any of Claims 1 to 13, characterized in that the valve means (31, 131) have stop means which limit movements of the blocking element (65, 165) in the direction away from the valve seat (149c, 49c) and define an open position for said blocking element.

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