WO2012120034A1 - Silencieux conçu pour un appareil à moteur - Google Patents

Silencieux conçu pour un appareil à moteur Download PDF

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Publication number
WO2012120034A1
WO2012120034A1 PCT/EP2012/053898 EP2012053898W WO2012120034A1 WO 2012120034 A1 WO2012120034 A1 WO 2012120034A1 EP 2012053898 W EP2012053898 W EP 2012053898W WO 2012120034 A1 WO2012120034 A1 WO 2012120034A1
Authority
WO
WIPO (PCT)
Prior art keywords
flow
chamber
exhaust gas
silencer
catalyst
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP2012/053898
Other languages
German (de)
English (en)
Inventor
Christian Kellermann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Makita Corp
Original Assignee
Makita Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE202011000527U external-priority patent/DE202011000527U1/de
Priority claimed from DE202011000536U external-priority patent/DE202011000536U1/de
Application filed by Makita Corp filed Critical Makita Corp
Publication of WO2012120034A1 publication Critical patent/WO2012120034A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features
    • F01N13/002—Apparatus adapted for particular uses, e.g. for portable devices driven by machines or engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling
    • F01N1/089—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling using two or more expansion chambers in series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2230/00—Combination of silencers and other devices
    • F01N2230/04—Catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2260/00—Exhaust treating devices having provisions not otherwise provided for
    • F01N2260/14—Exhaust treating devices having provisions not otherwise provided for for modifying or adapting flow area or back-pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2590/00—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines
    • F01N2590/06—Exhaust or silencing apparatus adapted to particular use, e.g. for military applications, airplanes, submarines for hand-held tools or portables devices

Definitions

  • the present invention relates to a silencer for a two-stroke engine of an engine working device, in particular for a hand-operated engine working device such as a garden and green area maintenance device, a hand tool such as a chainsaw, a circular saw or a power cutter or for a moped, a boat engine and the like, wherein the muffler a silencer inlet, to which a flow channel connects, so that the flow channel can be attached by means of the silencer inlet to an outlet of the combustion chamber of the two-stroke engine, the flow channel at the silencer inlet opposite channel end opens into a first chamber, wherein a second chamber is further provided into which exhaust gas flows in through a main outlet branched off from the flow channel and from which the exhaust gas flows out through an outlet, the flow channel thus flowing between the muffler inlet and the first chamber is cheap swiss formed such that the air flowing into the muffler inlet exhaust gas due to its inertia mainly flows into the first chamber and flows again back after fill
  • a generic type silencer is shown in arrangement on a two-stroke engine, the advice for a Motorarbeitsge- device such as a garden and greenery care device or a hand tool such as a chainsaw, a circular saw or a power grinder or for a moped, a boat engine and the like.
  • the silencer shown has a silencer inlet which is connected to the outlet of the combustion chamber of the two-stroke engine.
  • the silencer inlet is adjoined by a flow channel, which opens into a first chamber via a channel end.
  • the flow channel and the first chamber are enclosed by way of example by a larger second chamber, wherein the first chamber can also be arranged outside the second chamber.
  • a gas barrier in the form of a counterpressure can form in the direction of the combustion chamber of the two-stroke engine, by means of which a harmful after-outlet of unburnt fuel-air mixture is reduced or even avoided. Also unburned fuel-air mixture already in the muffler can be returned by the backflowing exhaust gas into the combustion chamber of the two-stroke engine.
  • the flow channel is currently running, so that the einsch manende via the muffler inlet into the flow channel exhaust first flows at least predominantly into the first chamber and generates an overpressure in the first chamber.
  • a large part of the exhaust gas flows back in the direction of the silencer inlet, and forms a gas barrier, which prevents the fuel-air mixture, which has been charged into the combustion chamber of the cylinder, from entering the silencer unburned.
  • the geometric configuration of the flow channel and the first chamber with the respective volumes is determined such that a flow behavior of the exhaust gas in the flow channel and the first chamber is formed with the stroke of the piston and the opening of the outlet of the combustion chamber in the region of the bottom dead center of the piston corresponds. This achieves better emission values, in particular the efficiency of the two-stroke engine can be increased by reducing the emission of unburned fuel compared to conventional silencers.
  • the object of the present invention is therefore to further improve the flow behavior in the flow channel of a silencer of the aforementioned type. Furthermore, the object of the present invention is therefore to further develop a silencer for a two-stroke engine of an engine operating device of the aforementioned type, in particular in order to provide improved emission values of the engine working device.
  • the invention includes the technical teaching that at least one flow rectifier is arranged in the flow path of the exhaust gas between the silencer inlet and the outlet.
  • an improvement of the flow behavior of the exhaust gas through the muffler can be achieved.
  • the flow behavior of a gas that flows through a flow channel can have less turbulences in the flow channel when a flow rectifier is arranged, and the flow in a flow channel can have a lower flow resistance through a flow straightener.
  • a directional flow is forced through a flow straightener, which may correspond to the channel flow direction into which the flowing gas is directed along the flow channel.
  • the filling of the first chamber with exhaust gas and the backflow of the exhaust gas from the first chamber in the direction of the outlet of the combustion chamber is thus facilitated by the arrangement of a flow rectifier, in particular in the flow channel of the muffler. It could be determined that when a flow rectifier was arranged in the flow channel, the back pressure formed by the backflowing exhaust gas could be improved against the outlet of the combustion chamber.
  • at least one flow rectifier can be arranged with particular advantage in the flow channel of the muffler.
  • the flow straightener may be flowed through from both directions of the channel flow direction, namely, when the exhaust gas from the silencer inlet flows into the first chamber, and when the exhaust gas from the first chamber flows back toward the silencer inlet.
  • the transfer of a turbulent exhaust gas flow into a rectified exhaust gas flow can be used advantageously both for the first flow and for the second flow.
  • the flow resistance can also be reduced by reducing vortex losses.
  • the flow rectifier can be arranged adjacent to the muffler inlet in the flow channel.
  • the main outlet which forms the flow connection between the flow channel and the second chamber, is particularly far removed from the first chamber is arranged.
  • the exhaust gas which leaves the combustion chamber via the outlet and flows into the muffler inlet, does not escape into the second chamber through the main outlet before reaching the first chamber.
  • the advantage can be exploited that the main outlet is also arranged as close as possible to the muffler inlet, which results in a particularly large distance between the main outlet and the first chamber.
  • the advantage is utilized that the exhaust gas flow through the flow channel from the first chamber in the direction of the muffler inlet can then flow back into the or in the direction of the combustion chamber, if the flow of the exhaust gas is as rectilinear as possible.
  • a flow straightener arranged in the flow channel, in particular adjacent to the muffler inlet so even the length of the flow channel can be reduced. As a result, the flow channel with a flow rectifier can be made shorter than a flow channel in which no flow rectifier is introduced.
  • a likewise advantageous arrangement of a flow rectifier results if it is arranged adjacent to the channel end in the flow channel.
  • the flow rectifier By means of the flow rectifier, both the exhaust gas entering the chamber and the flow behavior can be positively influenced, but in particular the exhaust gas flowing back into the flow channel from the first chamber can already have a directed flow when it flows into the flow channel, and the flow behavior can be determined by the adjoining flow channel further along the channel flow direction be improved in order to obtain the lowest possible turbulence of flowing in or towards the combustion chamber exhaust gas.
  • the or a further flow rectifier can be arranged in the first chamber.
  • the flow behavior of the exhaust gas in the first chamber can be positively influenced, insofar as turbulence is minimized as much as possible when the exhaust gas flows in and out of the first chamber.
  • a preferred direction of the exhaust gas when entering and exiting into and out of the first chamber can be achieved by a flow rectifier in the first chamber, and the exhaust gas can either be merely compressed in the first chamber and expanded again, or the exhaust gas flows through the first chamber at least partially by adjusting a directional vortex formation in the first chamber by the arrangement of a corresponding flow straightener.
  • the flow rectifier may have a cross lamellar structure and / or a fan structure.
  • the function of a flow rectifier is based on the fact that the cross section of the flow channel through which the exhaust gas flows is divided into a plurality of smaller flow channels. This division can be done by a cross-lamellar structure and / or by a fan structure, and the cross-sectional structure of the flow straightener does not change in the flow direction.
  • the cross lamella structure and / or by the fan structure several smaller flow channels are formed, which are parallel to each other and have smaller individual cross sections in which vortex formation is suppressed or in which vortices, with which the exhaust gas enters the flow straightener, degraded over the flow path of the flow rectifier so that the exhaust leaves the flow straightener with a directed flow substantially parallel to the channel flow direction.
  • the cross lamellar structure may be formed of a plurality of horizontal and a plurality of vertical elements of a flat extension, which are brought into one another as a cross structure. Consequently, a flow in a cross lamellar structure undergoes positive guidance over the total transverse direction both in a horizontal direction and in a vertical direction. cut the flow channel.
  • a fan-shaped structure can be formed from a multiplicity of surface elements running parallel to one another, but which does not have any further surface elements arranged transversely to the course of the surface elements.
  • a flow straightener with a fan structure can be arranged particularly advantageously adjacent to the silencer inlet, and the exhaust gas, which flows with a directed pulse from the combustion chamber first against the lower side of the flow channel facing towards the crankcase, does not already have by a Flow rectifier are guided with a cross-lamellar structure, which can cause strong flow losses.
  • the flow through a fan structure of the flow straightener may already be rectified in the lateral direction, and a flow straightener with a cross-blade structure may join a flow straightener of a fan structure toward the first chamber.
  • Form has, through which the exhaust gas when flowing through the flow rectifier undergoes a twist around the channel flow direction.
  • the rectifier can generate a directional flow with and without spin.
  • additional effects such as lower pressure losses in the flow of the exhaust gas can be achieved, with reaction torques can be achieved on the back to the cylinder exhaust gases in non-centric position of the flow channel to the cylinder, also reaction moments of the volume of the first chamber flowing exhaust gases be achieved for filling the chamber.
  • a further advantage can be achieved in that the flow rectifier has a catalytic function.
  • a catalyst function in the flow rectifier both a rectification of the exhaust gas flow and a catalyst function can be achieved, so that two functions are integrated in one component.
  • the catalyst function in addition to the improvement in the emission values of the engine working device due to the streamlined design of the flow channel and the resulting flow effect of the exhaust gas to form a back pressure against the opening in the combustion chamber of the two-stroke engine.
  • tion of the exhaust gas values can be achieved by the fact that in the muffler of the aforementioned type with a flow straightener at the same time a catalytic function is implemented, so that the exhaust gases of the two-stroke engine do not reach the environment unpurified. Due to the catalytic function, the hydrocarbons can be converted to carbon dioxide or carbon monoxide with the help of the residual oxygen content. For lower conversion rates, that is not all hydrocarbons in the exhaust gases are converted into carbon dioxide or carbon monoxide, nevertheless, a significant improvement in the exhaust gas emissions of the engine tool is achieved because the benefits of exhaust gas recirculation is superimposed on the advantageous function of the flow rectifier with the catalyst function.
  • the flow rectifier may in particular have a honeycomb structure, wherein the surface of the honeycomb structure has a catalyst layer.
  • a flow straightener having a cross-lamellar structure and / or a fan structure may be provided with a catalyst layer to achieve the desired effect of exhaust gas purification.
  • the advantage of a large surface area of a cross lamella structure and / or a honeycomb structure can be used to advantage if these surfaces are provided with the catalyst layer.
  • the flow rectifier can be arranged in the main outlet and / or in the second chamber and / or in the outlet.
  • the arrangement of a flow rectifier in the main outlet or in the outlet through which the exhaust gas leaves the second chamber there are advantages in terms of the flow behavior of the exhaust gas, in particular, flow resistances can also be reduced here.
  • the flow rectifier may be formed as an insert, which is inserted into a preferably formed of two halves flow channel and / or in a preferably formed from two halves first chamber before joining the two halves between them.
  • the components formed by the two halves of the Flow channel and / or the first chamber are placed on each other after inserting the at least one flow straightener, and the halves, preferably made of sheet metal are crimped or welded together, for example.
  • the flow rectifier can also be arranged with a joining process in, for example, one of the two halves, through which the flow channel and / or the first chamber, but for example, the second chamber is formed, fixed or self-holding, and then we with the second half the first half on each other.
  • the invention further includes the technical teaching that at least one catalytic converter is arranged in the exhaust gas mass flow from the muffler inlet to the outlet.
  • the invention is based on the idea, in addition to improving the emission levels of the engine by the streamlined design of the flow channel and thus achieved flow effect of the exhaust gas to form a back pressure against the opening in the combustion chamber of the two-stroke engine to achieve a further improvement of the exhaust gas values that at least one catalytic converter is integrated into the silencer of the type described above.
  • at least one catalyst is arranged in addition to the streamlined shape of the flow channel and the effects caused thereby in the muffler, so that the exhaust gases flow partially or completely through the catalyst before they leave the muffler through the outlet and step outside.
  • the catalyst can be arranged at any point in the exhaust gas mass flow from the muffler inlet to the outlet of the muffler, wherein the exhaust gas mass flow also comprises the flow through the first chamber.
  • the at least one catalyst enables after-treatment of the exhaust gas with the components contained in the exhaust gas.
  • the existing hydrocarbons are converted with the help of the residual oxygen content to carbon dioxide or carbon monoxide.
  • the effect of the catalyst is superimposed on the effect that is achieved by the exhaust gas flow in the flow channel and thereby periodically generated back pressure towards the combustion chamber of the engine tool.
  • the catalyst may be designed as a catalyst element with spatial dimensions, by which an integration of the catalyst element in the exhaust gas mass flow within the muffler is made possible.
  • the catalyst element may be designed with the spatial dimensions such that no substantial structural adjustments are required in order to integrate the catalyst element in the silencer of the aforementioned, known type.
  • the dimensions of the catalyst element may depend on the installation situation of the catalyst element in the exhaust gas mass flow of the muffler, and according to the basic idea of the present invention, the catalyst element can be integrated in any region of the muffler through which the exhaust gas flows.
  • the catalyst element can be arranged with particular advantage in the flow channel, so that a multiple flow through the catalyst element with exhaust gas is made possible, wherein the catalyst element can be designed in particular as a honeycomb catalyst.
  • the effect that the exhaust gas initially flows from the silencer inlet in the direction of the first chamber, and flows back from the first chamber in the direction of the silencer inlet after filling the first chamber, can be used in addition to the formation of the back pressure to the combustion chamber of the two-stroke engine, namely that the exhaust gas flows through the catalyst element several times, whereby the conversion rate of the exhaust gas can be significantly increased.
  • the exhaust gas flows through the catalyst element in the flow channel when it is expelled from the combustion chamber of the two-stroke engine and flows from the muffler inlet toward the channel end.
  • the exhaust gas is first partially converted, and upon a further passage of the catalyst element from the first chamber in the direction of the silencer inlet, a further conversion of the exhaust gas can take place.
  • the exhaust gases forcibly hit the catalyst element, and the catalyst element can be flowed through both from a first direction and from a second direction. Only then can the exhaust gases leave the flow channel through the main outlet and into the second chamber and finally through the outlet in the second chamber to the outside.
  • the catalyst element can be arranged in the first chamber, wherein the catalyst element can be designed in particular as a lattice catalyst.
  • the advantage in carrying out the catalyst element as a lattice catalyst lies in the simpler and therefore more cost-effective embodiment, and in particular compared to honeycomb catalysts, the production of two-dimensional lattice catalysts is particularly simple and correspondingly inexpensive. Since the exhaust gas flows into the first chamber and flows back out of this after the formation of an overpressure in the first chamber, a lattice catalyst in the first chamber can also be repeatedly flowed through alternately.
  • the grid catalyst may be arranged in the front region of the first chamber, which points in the direction of the channel end.
  • the rear region of the chamber forms a reflection space
  • the lattice catalyst can extend over the entire cross-sectional area of the first chamber.
  • the exhaust gases are reflected in a controlled manner in the rear of the first chamber, and the grid catalyst can flow approximately uniformly over the entire catalyst surface become. This avoids that only a central region of the lattice catalyst is flowed through to achieve the catalyzing effect.
  • the lattice catalyst in the first chamber may alternatively or in addition to a honeycomb catalyst be arranged in the flow channel.
  • a catalyst element which is designed as a lattice catalyst can also be introduced in the flow channel.
  • catalyst elements in the region of the flow channel and the first chamber can achieve a damping effect which damps the flow of the exhaust gas between the first chamber and the silencer inlet.
  • the flow resistance that the catalyst element opposes to the exhaust gas mass flow can be determined so that a desired flow duration is achieved, and that the flow time of the exhaust gas in the flow channel and in the first chamber can be adjusted to the stroke movement of the piston of the two-stroke engine.
  • the catalyst element can be arranged in the main outlet of the muffler.
  • the main outlet forms the connection between the flow channel and the second chamber, or the exhaust gas which has first passed into the first chamber and has swung back towards the muffler inlet, can leave the first chamber via the flow channel and the main outlet and into the second chamber enter. This allows a large portion of the exhaust gas to pass through the catalyst element to further increase the conversion rate.
  • the main outlet of the silencer between the flow channel and the second chamber may have an outlet end, wherein the catalyst element may be arranged at the end end at the main outlet, wherein a bypass may be provided between the catalyst element and the outlet end, by the exhaust gas as a side stream to the catalyst element from the main outlet into the second chamber can pass.
  • a bypass may be provided between the catalyst element and the outlet end, by the exhaust gas as a side stream to the catalyst element from the main outlet into the second chamber can pass.
  • the catalyst element can be arranged in alignment with the main outlet be, so that the catalyst element can be directly flowed through the exhaust gas that passes through the main outlet.
  • any pressure peaks may flow out of the catalyst element through the bypass, and the bypass may be in the form of side openings between the outlet end and the catalyst element.
  • the catalyst element can be arranged in the second chamber.
  • the catalyst element may be formed as a knit catalyst.
  • These can be used particularly advantageously for the silencer of the present design, since knit catalysts are otherwise characterized only by a short service life due to vibrations and pressure pulsations.
  • the risk of flame formation at the exit from the second chamber is also reduced, especially when knitted catalysts are used.
  • the pressure pulsation in the course of the exhaust gas mass flow is reduced by the fact that the exhaust gas has a flow behavior in the flow channel between the first chamber and the silencer inlet.
  • pressure peaks are reduced, which usually arise during periodic opening of the outlet of the combustion chamber. Due to the counterpressure that arises due to the exhaust gas flowing back in the direction of the muffler inlet, pressure peaks are smoothed, and fabric catalysts can advantageously be used, in particular as an arrangement in the second chamber.
  • the catalyst element can be arranged on the inside in the second chamber in front of the outlet.
  • a catalyst element arranged in front of the outlet can again be embodied as a honeycomb catalyst, but also as a lattice catalyst or knitted catalyst.
  • the catalyst may also be formed in the form of a catalyst layer and applied to at least one of the surfaces of the muffler in contact with the exhaust gas mass flow.
  • the catalyst layer can be applied, for example, on the inside in the flow channel, since it is repeatedly passed through with exhaust gas, so that a particularly high conversion rate of the exhaust gas can be achieved.
  • the inside of the main outlet may be formed with a catalyst layer, wherein Also, the inside of the first chamber and / or the second chamber may have a catalyst layer.
  • FIG. 1 shows a schematic view of an embodiment of a silencer in arrangement on a two-stroke engine
  • FIG. 2 shows an exemplary embodiment of a silencer with a flow rectifier, which is arranged adjacent to the first chamber, FIG.
  • FIG. 3 shows an exemplary embodiment of a silencer with a flow rectifier, which is arranged over the entire length of the flow channel and designed differently,
  • FIG. 4 shows a cross-sectional view of the flow channel of the muffler, in which a flow rectifier with a cross lamella structure is introduced
  • FIG. 5 shows a cross-sectional view of the flow channel of the muffler, in which a flow rectifier is introduced with a fan structure
  • FIG. 6 shows a further exemplary embodiment of a silencer with a main outlet pointing downwards in the direction of the crankcase of the two-stroke engine
  • FIG. 7 shows an exemplary embodiment of a silencer with a flow rectifier, which is arranged in the main outlet
  • FIG. 8 shows a schematic view of a muffler arranged on a two-stroke engine with the arrangement according to the invention of a catalyst element in the flow channel
  • FIG. 9 shows an exemplary embodiment of the silencer with the arrangement of a catalyst in the first chamber
  • FIG. 10 shows an exemplary embodiment of a silencer with the arrangement of a catalyst in the main outlet
  • Figure 11 shows another embodiment of the muffler with a catalyst element in arrangement at the outlet end of the main outlet and Figure 12 shows an embodiment of the muffler with a catalyst element in the outlet of the second chamber.
  • Figure 1 shows a muffler 100 in arrangement on a two-stroke engine 10.
  • the two-stroke engine 10 has a cylinder 18 in which a combustion chamber 13 is formed.
  • the combustion chamber 13 is movably limited by the piston 21, which is guided in a liftable manner in the cylinder 18 and is connected via a connecting rod 23 to a crankshaft 22 to form a crank mechanism.
  • the cylinder 18 is arranged in a known manner on a crankcase 24 in which the crankshaft 22 is mounted.
  • an outlet is arranged, on which the muffler 100 is flanged via a muffler inlet 11 in a manner not shown in detail.
  • the silencer inlet 11 is adjoined by a flow channel 12, which opens into a first chamber 15 with a channel end 14 opposite the silencer inlet 11 and extends between the silencer inlet 11 and the first chamber 15 along a channel flow direction 12 '. Furthermore, the muffler 100 has a second chamber 16, which is formed larger than the first chamber 15 and enclosing the first chamber 15 by way of example completely and a part of the flow channel 12. The exhaust gas entering the muffler inlet 11 can first at least for the most part reach the first chamber 15, wherein a main outlet 17 is arranged on the flow channel 12, and the exhaust gas can pass from the flow channel 12 through the main outlet 17 into the second chamber 16.
  • the first chamber 15 has a secondary outlet 20, so that exhaust gas can flow from the first chamber 15 directly into the second chamber 16.
  • the exhaust gas can leave the muffler 100 through an outlet 19, which is introduced in the wall of the second chamber 16 and reach the outside.
  • the flow channel 12 is formed so aerodynamically favorable that the exhaust gas flowing into the muffler inlet 11 mainly flows into the first chamber 15 due to its inertia and flows back to the muffler inlet 11 after filling the first chamber 15 to a against the outlet of the combustion chamber 13 a To form back pressure.
  • the streamlined design of the flow channel 12 is further improved according to the invention by the arrangement of a flow rectifier 25, which is arranged according to the embodiment shown in the flow channel 12.
  • the flow rectifier 25 causes a lower turbulence and along the channel flow direction 12 'directed flow of the exhaust gas in the flow channel 12. This vortex losses are reduced, and the flow of the exhaust gas from the combustion chamber 13 into the first chamber 15 and back from the first chamber 15 into the combustion chamber 13 further favored. Thereby, the length of the flow channel 12 can be further reduced, and the flow channel 12 can have a smaller minimum length to form a directional flow behavior of the exhaust gas along the channel flow direction 12 '.
  • the exemplary embodiment shows an arrangement of the flow rectifier 25 directly at the muffler inlet 11, so that the exhaust gas, which enters the muffler 100 from the combustion chamber 13, flows through the flow rectifier 25 directly.
  • the flow rectifier 25 is designed such that the cross section of the flow channel 12 is divided into many individual cross sections, which extend approximately along the channel flow direction 12 '. This vortex can be prevented or resulting vortices are reduced, and the flow of the exhaust gas in the flow channel 12 follows approximately a laminar, vortex-free or at least low-turbulence flow.
  • the example shows the arrangement of the flow rectifier 25 between the sound damper inlet 11 and the arrangement of the main outlet 17, through which the exhaust gas from the flow channel 12 can flow into the second chamber 16.
  • Figure 2 shows another embodiment of a muffler
  • a flow rectifier 25 is provided, which is arranged adjacent to the silencer inlet 11 opposite channel end 14. As a result, the flow rectifier 25 is located along the channel flow direction 12 'between the main outlet 17 and the channel end 14, in which the flow channel 12 merges into the first chamber 15.
  • a further embodiment is shown, wherein the arrangement of a flow rectifier 25 according to the embodiment in Figure 1 with the arrangement of a further flow rectifier 25 according to the embodiment in Figure 2 also combined in the flow channel 12 can be arranged.
  • a flow rectifier 25 can be arranged in the main outlet 17, in order to reduce or avoid a vortex formation in the main outlet 17 as well.
  • FIG. 3 shows a further exemplary embodiment of a silencer
  • a flow rectifier 25 which extends along the entire flow channel 12 from the muffler inlet 11 to the channel end 14.
  • the flow rectifier 25 is designed, for example, with a different structure, and the region of the flow rectifier 25 which extends between the main outlet 17 and the channel end 14 has a cross-lamella structure 25a.
  • the exhaust gas is first aligned in the lateral direction, and in the direction corresponding to the piston stroke direction, the exhaust gas over the entire height of the flow channel 12 can flow freely.
  • This achieves the advantage that the exhaust gas, which receives an impulse directed approximately transversely to the channel flow direction 12 ', first flows against the lower side of the flow channel 12, and the exhaust gas does not have to flow through a cross-lamella structure 25 a already when it enters the muffler inlet 11 , which in addition to the vertically extending flow lamellae additionally has horizontally extending flow lamellae.
  • the exhaust gas can enter the cross-lamella structure 25 a, and the exhaust gas can enter the first chamber 15 in a swirl-free manner.
  • this first passes through the cross lamella structure 25a, which is followed by the fan structure 25b, until the exhaust gas from the muffler inlet 11 can flow against the combustion chamber 13.
  • the flow rectifier 25 is shown, which has both a cross-blade structure 25a and a fan structure 25b.
  • FIG. 4 shows a cross section through the flow channel 12 with a first chamber 15 adjoining it, and a flow rectifier 25 with a cross lamella structure 25a is introduced in the flow channel 12.
  • This has both vertical and horizontal slats, which are formed merge into one another.
  • a honeycomb structure which can be used at the same place as well as a cross-lamella structure 25a.
  • FIG. 5 shows a further cross-sectional view of a flow channel 12 with a first chamber 15 adjoining it.
  • a flow rectifier 25 is introduced, which has a Kla- cher Quilt 25 b, and the fan elements are aligned in the vertical.
  • the flow rectifier being an example 25 with the fan structure 25 b can connect a flow rectifier 25 with a cross-blade structure 25 a.
  • FIG. 6 shows a further exemplary embodiment of a silencer 100 having a flow channel 12 which extends between a silencer inlet 11 and a channel end 14.
  • a first chamber 15 connects, wherein a second chamber 16 is provided, which preferably surrounds the first chamber 15 and a part of the flow channel 12.
  • a main outlet 17 is arranged, which faces downward, and is thus aligned in the direction of the crankcase.
  • a flow rectifier 25 is arranged, which has, for example, a cross-blade structure 25a or a honeycomb structure.
  • the exhaust gas is already aligned in the channel flow direction 12 'both horizontally and in particular in the vertical direction, and the exhaust gas entering the silencer inlet 11 from the combustion chamber 13 can not escape mainly through the main outlet 17, but at least passes
  • the combustion chamber 13 is located above the flow channel 12, so that at least a majority of the exhaust gas receives a pulse which extends in the direction of the lower side of the flow channel 12, but is made possible by the flow rectifier 25, that despite the pulse of the exhaust gas in the direction of the lower side of the flow channel 12 can be arranged at this the main outlet 17, since the exhaust gas is already aligned by the flow rectifier 25 in the Kanalströmungs- direction 12 '.
  • FIG. 7 shows an exemplary embodiment of a muffler 100 with a flow rectifier 25, which is arranged in the main outlet 17.
  • a final embodiment is shown, which proposes an arrangement of the flow rectifier 25 in an important flow section of the exhaust gas through the muffler 100, in particular, the flow behavior of the exhaust gas can be influenced by this arrangement of the flow rectifier 25 particularly positive.
  • Figure 8 shows a muffler 200 in the arrangement on a two-stroke engine 110.
  • the two-stroke engine 110 has a cylinder 118 in which a combustion chamber 113 is formed.
  • the combustion chamber 113 is movably bounded by the piston 121, which is guided in a lift-movable manner in the cylinder 118 and is connected via a connecting rod 123 to a crankshaft 122 to form a crank mechanism.
  • the cylinder 118 is arranged in a known manner on a crankcase 124, in which the crankshaft 122 is mounted.
  • an outlet is arranged, on which the muffler 200 is flanged via a muffler inlet 111 in an unspecified manner. If the piston 121 is in the illustrated position of the bottom dead center, it releases the outlet of the combustion chamber 113, and the exhaust gas can pass from the combustion chamber 113 through the muffler inlet 111 into the muffler 200.
  • the silencer inlet 111 is adjoined by a flow channel 112, which opens into a first chamber 115 with a channel end 114 opposite the silencer inlet 111. Further, the muffler 200 has a second chamber 116, which is formed larger than the first chamber 115 and the first chamber 115, for example, completely and encloses a part of the flow channel 112.
  • the exhaust gas entering the muffler inlet 111 may first pass into the first chamber 115 at least to a major extent, a main outlet 117 being arranged on the flow channel 112, and the exhaust gas being able to pass from the flow channel 112 through the main outlet 117 into the second chamber 116 , Furthermore, the first chamber 115 has a secondary outlet 120, so that exhaust gas can also flow from the first chamber 115 directly into the second chamber 116.
  • the exhaust gas can leave the muffler 200 through an outlet 119, which is introduced in the wall of the second chamber 116 and reach the outside.
  • the flow channel 112 is designed so that the exhaust gas flowing into the muffler inlet 111 predominantly flows into the first chamber 115 and, after filling the first chamber 115, flows back toward the muffler inlet 111 in order to counter the outlet of the combustion chamber 113 to form a back pressure. This ensures that unburned fuel Air mixture is not uncontrolled enters the flow channel 112, while the piston 121 of the two-stroke engine 110 is in the region of the bottom dead center, and a charge change in the combustion chamber 113 takes place. Due to the flow-favorable design of the flow channel 112, the exhaust gas first passes through the muffler inlet 111 into the first chamber 115, and fills it. Subsequently, the exhaust gas flows due to an overpressure in the first chamber 115 back toward the muffler inlet 111, so that the flow channel 112 is alternately flowed through with exhaust gas.
  • a catalyst element 125 is shown in the region between the main outlet 117 and the channel end 114 arranged in the flow channel 112.
  • the catalyst element 125 By flowing into the first chamber 115 and again flowing out of the first chamber 115 exhaust gas, the catalyst element 125, for example in the form of a honeycomb catalyst, alternately flows through at least twice.
  • the arrangement of the catalyst element 125 is shown merely by way of example, and the catalyst element 125 can also be advantageously arranged between the main outlet 117 and the muffler inlet 111 in the flow channel 112.
  • FIG. 9 shows a further exemplary embodiment for arranging a catalyst element 125 in the first chamber, and the catalyst element 125 shown is designed as a lattice catalyst by way of example.
  • This may, for example, have a stainless steel carrier grid, and be approximately perpendicular to the longitudinal extent of the flow channel 112 in the first chamber 115. If the exhaust gas flows from the silencer inlet 111 through the flow channel 112 into the first chamber 115, then the exhaust gas flows through the lattice-like catalyst element 125 when it enters the first chamber 115. If overpressure builds up in the rear region of the first chamber 115 after it has been filled, then flows the exhaust gas back to the flow channel 112, and the grid catalyst 125 is now flowed through again from the opposite direction with exhaust gas. Subsequently, the exhaust gas can enter the second chamber 116 through the main outlet 117 and finally exit via the outlet 119.
  • FIG. 10 shows a further exemplary embodiment of a muffler 200 with a flow channel 112 that extends between the muffler inlet 111 and the first chamber 115.
  • a Main outlet 117 through which the exhaust gas from the flow channel 112 can enter the second chamber 116.
  • the exhaust gas may also leave the second chamber 116 through the outlet 119.
  • a respective catalyst element 125 is shown arranged, and the exhaust gas flowing through the main outlet 117, flows through the catalyst element 125, and it can be a post-treatment of the exhaust gas through the catalyst element 125.
  • FIG. 11 shows a further exemplary embodiment of a muffler 200 having a flow channel 112 which extends between a muffler inlet 111 and a first chamber 115. Furthermore, a main outlet 117 is arranged on the flow channel 112, through which the exhaust gas from the flow channel 112 can enter the second chamber 116 and leave it through the outlet 119. According to this embodiment, a catalyst element 125 is disposed at the outlet end 117a of the main outlet 117. Between the catalyst element 125 and the outlet end 117a, a bypass 126 is provided, which may be formed, for example, in the form of an annular gap formed by the stationary outlet end 117a.
  • FIG. 12 shows a last exemplary embodiment of a muffler 200 with a flow channel 112 that extends between a muffler inlet 111 and a first chamber 115.
  • a main outlet 117 is shown, through the exhaust gas from the flow channel 112 can enter the second chamber 116.
  • the exhaust gas entering the second chamber 116 finally passes through the outlet 119 into the open, wherein in the outlet 119, a catalyst element 125 is introduced.
  • the entire exhaust gas flows through the catalyst element 125, and in particular by the arrangement of the catalyst element 125 in the outlet 119, a further sound-insulating effect of the muffler 200 can be achieved.
  • the arrangements of the catalyst elements 125 shown can be combined as desired.
  • one or more catalyst elements 125 can be arranged in the flow channel 112, for example a first catalyst element 125 between the muffler inlet 111 and the main outlet 117 and a further catalyst element 125 between the main outlet 117 and the channel end 114 or the first chamber 115.
  • a grid catalytic converter 125 may be introduced into the first chamber 115, with further catalyst elements 125 being able to be arranged in the main outlet 117 or at a distance from the outlet end 117a of the main outlet 117 or alternatively or additionally in the outlet 119 further catalyst elements 125.
  • a catalyst 125 may also be formed by a catalyst layer 127, which is indicated by way of example in FIG. 12 in the inner wall of the flow channel 112.
  • catalyst layers 127 are known, which also enable after-treatment of the exhaust gas when the exhaust gas is conducted past the surface of the catalyst layer 127.
  • the application of a catalyst layer 127 can be implemented particularly advantageous, since the exhaust gas can flow through the flow channel 112 in the manner described above mutually.
  • a tubular catalyst 125 tubular and adjacent to an inner wall for example, the flow channel 112 to arrange. This may be advantageous, for example, if the flow behavior of the exhaust gas in the flow channel 112 is not to be influenced by a catalyst 125 or only slightly.
  • the invention is not limited in its execution to the above-given preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. Any features and / or advantages resulting from the claims, the description or the drawings, including constructive details or spatial arrangements, can be essential to the invention, both individually and in the most diverse combinations.
  • honeycomb catalysts lattice catalysts, knitted catalysts and the like
  • catalyst layers 127 in addition to the formation of catalyst elements catalyst layers can further be used on the surfaces of the components of the muffler 200, which are compatible with the exhaust gas mass flow during operation of the Muffler 200 are brought into contact.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Silencers (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

L'objectif de l'invention est d'améliorer un silencieux (100) conçu pour un moteur à deux temps (10) d'un appareil de travail à moteur, une conduite d'écoulement (12) étant formée entre l'admission de silencieux (11) et une première chambre (15) de manière à être avantageuse pour l'écoulement, de sorte que les gaz d'échappement affluant dans l'admission de silencieux (11) pénètrent principalement dans la première chambre (15) en raison de leur inertie de masse et en sortent à nouveau, après le remplissage de la première chambre (15) et qu'une contrepression se forme ainsi en direction de la chambre de combustion (13). Pour atteindre l'objectif de cette invention, au moins un rectificateur d'écoulement (25) est disposé sur le trajet d'écoulement des gaz d'échappement entre l'admission de silencieux (11) et l'évacuation (19) et/ou au moins un catalyseur (25, 27) est disposé sur le flux massique des gaz d'échappement allant de l'admission de silencieux (11) à l'évacuation (19).
PCT/EP2012/053898 2011-03-09 2012-03-07 Silencieux conçu pour un appareil à moteur Ceased WO2012120034A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE202011000536.4 2011-03-09
DE202011000527U DE202011000527U1 (de) 2011-03-09 2011-03-09 Schalldämpfer für ein Motorgerät mit einem Katalysator
DE202011000536U DE202011000536U1 (de) 2011-03-09 2011-03-09 Schalldämpfer für ein Motorgerät
DE202011000527.5 2011-03-09

Publications (1)

Publication Number Publication Date
WO2012120034A1 true WO2012120034A1 (fr) 2012-09-13

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ID=45808960

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Application Number Title Priority Date Filing Date
PCT/EP2012/053898 Ceased WO2012120034A1 (fr) 2011-03-09 2012-03-07 Silencieux conçu pour un appareil à moteur

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Country Link
WO (1) WO2012120034A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10239116A1 (de) * 2002-08-27 2004-03-04 Andreas Stihl Ag & Co Verbrennungsmotor
US20060026953A1 (en) * 2004-08-06 2006-02-09 Kioritz Corporation Catalyst-attached muffler for internal combustion engine
DE202005005328U1 (de) * 2005-04-04 2006-08-10 Dolmar Gmbh Zweitaktmotor
DE202008005168U1 (de) 2008-04-14 2009-08-27 Dolmar Gmbh Schalldämpfer für ein Motorgerät

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10239116A1 (de) * 2002-08-27 2004-03-04 Andreas Stihl Ag & Co Verbrennungsmotor
US20060026953A1 (en) * 2004-08-06 2006-02-09 Kioritz Corporation Catalyst-attached muffler for internal combustion engine
DE202005005328U1 (de) * 2005-04-04 2006-08-10 Dolmar Gmbh Zweitaktmotor
DE202008005168U1 (de) 2008-04-14 2009-08-27 Dolmar Gmbh Schalldämpfer für ein Motorgerät

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