WO2000066884A1

WO2000066884A1 - Manifold arrangement for exhaust systems

Info

Publication number: WO2000066884A1
Application number: PCT/AT2000/000115
Authority: WO
Inventors: Andreas Werth; Christian Skorianz
Original assignee: Andreas Werth; Christian Skorianz
Priority date: 1999-05-03
Filing date: 2000-05-03
Publication date: 2000-11-09
Also published as: JP2002543336A; ATE264990T1; US20020083703A1; DE50006155D1; AU4723200A; EP1177368B1; EP1177368A1

Abstract

The invention relates to a manifold arrangement for exhaust systems of internal combustion engines, especially multi-cylinder motorbike engines. Said arrangement is introduced between the exhaust gas outlet pipes coming from the or each cylinder and at least one exhaust silencer (14). The inventive arrangement is configured in such a way that the exhaust gas outlet pipes of the cylinders are combined step-by-step so as to form one joint pipe (7). A branch (8) is provided behind the joint pipe (7). Said branch (8) divides the flow of exhaust gas into at least two pipes (9, 10; 9', 10') which are separated from each other, are parallel in a flow-wise manner and together have a greater cross-sectional surface than the joint pipe (7). A joining element (11, 11') for one collector pipe (12, 12') is provided behind said pipes (9, 10; 9', 10'). The collector pipe (12, 12') is provided with a free flow cross-section which matches at least the surface sum of the parallel pipes (9, 10; 9', 10'). A component (13, 13') serving as a characteristic impedance is introduced into the continuing collector pipe (12, 12'). The component (13, 13') allows the exhaust gas volume flow to pass in an unhindered manner while pressure waves are forced to perform a total reflection on said component, whereby said total reflection is as complete as possible.

Description

Collector pipe arrangement for exhaust systems

The invention relates to a collector pipe arrangement for exhaust systems of internal combustion engines, in particular multi-cylinder motorcycle engines, for connection between the exhaust gas outlet lines from the or each cylinder and at least one muffler, the exhaust gas outlet lines of the cylinders possibly being combined step by step into finally a connecting pipe, a branch is provided behind this connecting pipe, which divides the exhaust gas flow into at least two separate, flow-parallel pipes with a total larger cross-sectional area than that of the connecting pipe, and behind these pipes a merger is again provided on a single manifold.

It is generally known in the field of exhaust construction that exhaust systems can contribute to increasing the performance of the engine, mainly due to the lengths of the exhaust pipes connected to the engine. The energy source for this increase in engine efficiency is the high residual pressure inside the cylinder at the end of the work cycle, which residual pressure suddenly discharges into the exhaust system when the exhaust valve or valves are opened. Modern simulation and design models for exhaust systems favor the wave approach for the explanation and calculation, according to which a large part of the energy of the exhaust gas enters into a shock wave, which spreads in the exhaust system and due to sudden increases or decreases in the cross-sectional areas partially and depending on the Sense of change in size is reflected as a pressure or vacuum wave. Each cylinder excites vibrations that remain at least until the next exhaust stroke of the same cylinder, whereby complex resonance patterns of residual vibrations can form in several cylinders, which come into resonance with the shock waves from the cylinders at critical speed or frequency ranges and in these resonance areas lead to a reduction in performance and an increase in noise levels.

The known approaches are not expedient because, for example, a "detuning" of the resonance frequency downwards is not one, especially in motorcycle construction would require realizable extension of the manifold. A "detuning" to a higher resonance frequency does not promise success, since the residual vibrations can ultimately be interpreted as harmonics of the ignition frequency of the individual cylinder. Acoustic damping of the manifold does not change the resonance behavior and therefore only leads to a slight quantitative improvement. On the other hand, it is very effective to switch an expansion volume into the exhaust gas duct, into which the exhaust pipes that determine the increase in output flow, if this volume is sufficiently large, which in turn encounters structural restrictions, in particular for motorcycles.

No. 4,819,428 A describes an exhaust system in which a single header pipe is provided between the exhaust pipes coming from the engine and two branch pipes leading to two silencers. The problem of the resonance of residual vibrations in the exhaust system with the shock waves of the exhaust gases is not discussed in any way. In the case of the silencer of DE 37 12 495 A, the task is at all only related to sound absorption and there is no reference to special designs of the pipes upstream of the silencer.

EP 421 724 discloses an arrangement with distribution of the exhaust gas flow over at least two pipelines with subsequent re-assembly. This arrangement works by damping standing waves by means of interference due to different lengths of the parallel pipes. As mentioned several times, pressure reactions in upstream areas of the exhaust line, for example by any wave resistance, should be avoided. It is also essential that the cross-sectional area of the parallel pipelines is at least equal to or larger than the input cross-sectional area and also at least equal to or larger than downstream sections. In US Pat. No. 4,206,177, according to which document a catalytic converter is arranged in a silencer and which provides a wave reflection wall between an expansion section and a silencing section, the task is to arrange a catalytic converter in such a way that, with full effectiveness, it shows as little reaction as possible on the pressure reflections. Quite different damping mechanisms are addressed here than in the aforementioned Reprimand. Furthermore, US 4,206,177 relates to the construction of the actual silencer at the very end of the exhaust line.

The object of the invention is therefore a collector pipe arrangement as described in the introduction, which offers a continuous increase in performance over the entire speed range of a multi-cylinder engine, with the greatest possible elimination of disadvantageous resonance phenomena with sufficient sound absorption, which can be realized at the smallest possible size, in particular the use to make it possible for motorcycles or not to unduly reduce the space available for other components in automobile construction.

This object is achieved in that the header has a free flow cross-section that corresponds at least to the area of the parallel pipes, and that a component is used as a wave resistance in this further header, which component allows the exhaust gas volume flow to pass unhindered, while pressure waves total reflection on this component must be forced. The distribution of the exhaust gas routing of the individual connecting pipe over at least two parallel pipes leads to the distribution of an undivided pressure wave in front of the tap on several waves, the energy of which corresponds to the original wave and which pass through the downstream, parallel channels as individualized and independent wave fronts. Since, according to the invention, there is a jump in area in relation to the free flow cross section of each of the parallel channels when the parallel pipelines are brought together into the individual, collectively further collecting pipe, the individualized wave fronts running through the individual channels at the respective channel mouth are added in the combination an effective partial wave reflection. The (negative pressure) waves resulting from this reflection run back in the direction of the branch in each of the individual parallel channels. Since there is a similar jump in area in relation to the free flow cross-section of each individual one of the interposed channels at the branch as at their merging, the arrangement proposed according to the invention causes one repeated reflection of wave energy from one and the same pressure wave, as a result of which a large part of the wave energy obtained in the proposed arrangement is processed, since the reflection is inevitably associated with energy losses.

The switching of a component proposed in the invention into the header pipe after the parallel pipes or ducts have been brought together, on which the pressure waves which, in contrast to the upstream surface jumps, are not forced to a partial, but to a total reflection, doubles the intensity of the processing of wave energy in the upstream parallel pipe sections, since the proportion of the original pressure wave, which has passed the tap, then the parallel pipes and their outlet into the junction on the common manifold, is also reflected in this wave resistance, which means that a considerable additional proportion of the Wave energy of the mutual reflection is supplied with appropriate processing. Another advantage of the component "wave resistance" is that on the one hand it dissolves the portion of wave energy that escapes the total reflection and passes it into a diffuse wave pattern, whereby the excitation of unwanted resonance vibrations in a downstream silencer is avoided. On the other hand, it reflects negative pressure waves, which result from the mutual reflections in the proposed arrangement and would run after the collector pipe in the direction of the muffler, as a similar negative pressure wave in the direction of the engine, whereby an additional portion of the original pressure wave energy is used to support the charge exchange.

The frequent reflection of a pressure wave in the sequence of cross-sectional changes and wave resistance according to the invention brings about a system-internal optimization of the sound damping of the exhaust system by efficient processing of pressure wave energy even in the pipeline sections upstream of the actual silencer. Furthermore, it causes an increase in the energy portion from the original pressure wave, which is reflected as a negative pressure in the direction of the engine. As a result, the arrangement proposed in the invention is able to compensate for the power loss which is usually associated with the connection of a muffler into the exhaust line of known exhaust arrangements. In order to ensure an effective reflection of the pressure wave emanating from a cylinder outlet of the engine in the exhaust system of the exhaust system and a first significant energy reduction in the proposed arrangement, it is provided that the total cross-sectional area of the parallel pipes is at least 25% larger than the free flow cross section of the Connection tube, preferably 40% to 60% larger. The area of the connecting pipe connected upstream of the parallel pipes or channels applies at the point where it joins the branch. So that this partial reflection of the pressure wave induced in the gas exchange support of the engine at the tap on the downstream parallel pipes is optimally effective, it is advantageous to place the tap in the exhaust pipe at such a distance from the engine that a favorable wave duration for the resulting from this reflection returning vacuum wave guaranteed.

The length of the parallel pipelines between the tap and the junction should advantageously correspond to at least twice the respective diameter of these pipes in order to ensure that separate and independent wave fronts can form in the parallel channels and that the original wave is not only spread briefly. One advantage of the proposed arrangement is that the total length of the parallel pipe pieces is irrelevant for the function, because the propagation times of the individual reflection waves within the arrangement are decoupled from the ignition frequency of the engine by the induced multiple wave reflection between the components according to the invention. This system property, together with the fact that the partial wave reflection taking place at the opening on the engine side of the tap roughly halves the energy of the returning waves through the exhaust system, leads to a decoupling of the downstream elements of the exhaust system, into which the silencer (s) are usually switched on the wave reflections on the exhaust pipes immediately downstream of the engine, which bring about the possible increase in efficiency through the exhaust system, while at the same time suppressing adverse resonance phenomena. To ensure this decoupling safely, it is advantageous to design the connecting pipe as a connecting link between the upstream outlet pipes and the arrangement according to the invention with a pipe length which corresponds at least to the diameter of said pipe.

An arrangement in which, according to a further feature of the invention, the parallel pipelines are designed as pipe sections running alongside one another with essentially parallel axes is very simple in construction and also very effective for cooling.

A division into several separate wave fronts running at different speeds due to the statistical distribution of the energies and thus the optimal avoidance of harmful resonances in the exhaust system with increased processing of wave energy is possible if more than two, preferably three parallel pipes are provided. The more pipelines are provided, the larger the necessary installation space, of course, so that embodiments with a maximum of three pipelines have proven to be advantageous especially for motorcycles.

In a structurally particularly simple design, the wave resistance is designed as a sheet metal provided with holes or slots.

According to a particularly advantageous embodiment, it is provided that the wave resistance is designed as an essentially axially parallel perforated plate cylinder, the end of which is closed towards the parallel pipes, while the other end is open to the downstream parts of the exhaust system, in particular the silencer. With this construction, a sufficiently large perforated plate surface and thus a sufficiently dimensioned wave resistance can be accommodated with little effort and with a small construction volume due to the good flushing of the perforated plate cylinder in the exhaust pipe.

The wave resistance can be increased for a given hole diameter if the holes or slots have a non-negligible longitudinal dimension or if they are axially extended by short pipe sections or protuberances of the sheet. This makes it easy to produce the desired characteristic impedance with hole sizes that are easy to manufacture. Advantageously, the wave resistance can also be a catalytic converter body with, for example, honeycomb shafts, as a result of which the prescribed limits for noise and exhaust gas emissions can be easily adhered to, even with motorcycles, with optimal and uniform performance increase with a very small size.

According to a further advantageous embodiment, the wave resistance is a porous metal or ceramic body, preferably made of sintered material. The wave resistance could also be an easy-to-manufacture scrim, knitted fabric or knitted fabric made of metal threads.

If the total cross section of the passage openings in the component of the wave resistance is greater than the total cross section of the parallel pipelines in any of the above-mentioned embodiments, the flow resistance is not or only slightly greater than that of the upstream exhaust system, thereby avoiding an unfavorable influence on the engine performance. It is advantageously provided that the total cross section of the passage openings is approximately 30% to 40% larger than the total cross section of the pipelines.

In order to prevent the pipeline between the junction and the wave resistance component from acting as a volume resonator and from building up natural vibrations which have a detrimental effect on the upstream system, the wave resistance is advantageously arranged immediately behind the junction, the distance to the end of which is a maximum of about double of the pipe diameter there.

According to an advantageous embodiment, to further increase the efficiency of the arrangement according to the invention, it can be provided that at least two taps and at least two junctions are provided in parallel with one another, the pipelines of each tap running to different junctions.

In this case, at least one connection between the parallel pipelines is advantageously provided in front of the or each branch.

In the following description, the invention is based on the attached drawings of preferred embodiments for an exhaust system according to the invention for motorcycles are explained in more detail. 1 shows a first embodiment of the invention for four-cylinder engines, FIG. 2 is a further variant for four-cylinder engines, FIG. 3 and its cross-section AA represent a special embodiment for the parallel pipelines, and FIG. 4 shows a further embodiment an exhaust system according to the invention with two taps, two parallel pipe arrangements and two wave resistors.

In the arrangement of FIG. 1, the primary exhaust pipes 1 to 4 of the individual cylinders of a four-cylinder engine, which are designed as usual, are combined in pairs, as is also already known and customary, into two secondary exhaust pipes 5 and 6. A corresponding arrangement is also common in six-cylinder engines, where groups of three primary exhaust pipes are then combined into a secondary pipe. The secondary exhaust pipes 5, 6 can optionally also have a cross-section other than circular, for example if they are constructed by dividing an individual pipe into two separate pipe halves. The secondary exhaust pipes 5, 6 assigned to a group of primary exhaust pipes are brought together in this known arrangement in a single manifold 7, which combines the exhaust gas flows of all cylinders and to which devices such as silencers or catalytic converters 14 are usually connected, which are also in a single component can be summarized. Corresponding arrangements are also common for eight- or twelve-cylinder engines, in each of which a cylinder bank is equipped with such an exhaust pipe elbow. The merging of the primary exhaust pipes immediately downstream of the individual cylinders into a common exhaust pipe is also common in two- or three-cylinder engines, with the difference that, according to the smaller number of cylinders, the primary exhaust pipes open directly into the individual manifold 7, which leads to a silencer or catalytic converter 1 leads.

In the arrangement according to the invention in FIG. 1, behind the collecting or. Connecting pipe 7 a branch 8 is turned on, which divides the exhaust gas flow into at least two downstream, parallel pipe sections 9 and 10. These pipe sections 9, 10 are then again combined by means of the merging 11 into a single manifold 12, in which a wave resistor 13 is switched on. The device 14, for example the muffler or the catalytic converter, is only connected to this collecting pipe 12 with wave resistance 13. As the section AA of FIG. 1 shows, the wave resistance 13 is advantageously arranged concentrically in the collecting tube 12.

The particular effectiveness of the proposed arrangement is based on the following physical causes: the nature of the propagation of shock waves induced by the opening of an engine outlet and the fundamental difference between partial and total reflection of these waves. The shock waves induced in the rhythm of the work cycles of a piston engine spread at the local speed of sound in the exhaust gas as a transmission medium inside the exhaust pipe towards the exhaust outlet. These waves are individual events that are strictly correlated with the opening of an engine outlet. Their nature corresponds to that of a shock wave on the occasion of an explosion or a sonic boom, because they too are the result of an abrupt entry of pressure energy into the transmission medium, which propagates there as a singular impulse with a single striking amplitude.

As a singular impulse, said shock waves should not be mistaken for standing waves that are established inside an exhaust system. Because the singular wave fronts of shock waves can run through one another without changing their momentum, comparable to two different waves on the surface of a lake, while two different standing waves inside the pipes of the exhaust pipe, depending on their phase difference, either in the mode of resonance or Overlay interference. Such standing waves in the interior of the exhaust system receive their excitation from said shock waves, but like the cause, they are distinguished from their effect.

EP 0 421 724 A1 describes a pipe arrangement for damping standing waves by means of interference. For effective damping of these waves, the fundamental frequency of which naturally corresponds to the ignition frequency of the engine, and is therefore between 100 and 400 Hertz, tube lengths are required, especially those available on a motorcycle Clearly exceed space. To make matters worse, a large difference in length between the parallel tubes is necessary in order to produce a phase difference which is sufficient for interference of the standing waves. In contrast, the length difference of the parallel tubes 9 and 10 of the proposed arrangement is completely irrelevant for their function. This is also proven by corresponding test series on the test bench.

According to the invention, the arrangement of branch 8, which divides the exhaust gas flow of the collecting pipe 7 into two parallel further pipe strings 9 and 10, which are subsequently reunited by a merging 11, serves as a means of producing surface jumps within the free flow cross section in the Exhaust system exhaust pipe. At such surface jumps, as are given at the tap 8 and at the junction 11, there is known to be a partial reflection of the shock wave, on the basis of which its pulse is split into two waves, one of which maintains the original direction of propagation towards the exhaust end, while the second Wave is reflected in the opposite direction.

The dimensioning rules listed below define the lower limit of the geometric proportions in an exhaust gas duct according to the invention, which are essential for the efficiency of the partial wave reflection. Thus, with the minimum length of the parallel tubes 9 and 10, which should preferably correspond to at least twice the respective diameter of these tubes, it is ensured that an undivided shock wave pulse in front of the tap 8 is divided into two pulses, the total energy of which, ideally, ie without taking into account inevitable wall losses, which corresponds to the original impulse. At the junction 11, each of the partial waves, which propagate in the pipes 9 and 10 towards the exhaust end, experiences a partial reflection at the surface jump, which the free flow cross section of this component represents in relation to the individual surface of the pipes 9 and 10. The partial nature of this reflection causes part of the pulse energy from each partial wave to be reflected back as branch shock waves against the original flow direction of the exhaust gas through the corresponding pipes back to branch 8, while the other part of the pulse energy as part shock waves themselves in the original Propagate propagation direction. The defined minimal area of the pipes 9 and 10 ensures a sufficiently large area at the tap 8, where a new and partial reflection of the (partial) waves returning through these pipes is brought about. With this second partial reflection within the arrangement, two shockwave pairs different in their direction of propagation are generated, one pair in the direction of the motor and the other pair as products of the second reflection, which again have the orientation of the original impulses.

The partial wave reflection of one and the same shock wave at the junction 11 as well as at the tap 8 binds a large portion - ideally half - of the pulse energy of the original shock wave within the arrangement, in that this leads to a mutual often reflection between the ends of the pipes 9 and 10 is forced. Carnot's shock loss, which inevitably occurs with each of these partial wave reflections, causes the pulse energy to be converted into heat and thus the original shock wave to be processed.

An arrangement of parallel pipes of a length, as described in EP 0 421 724 A1, would not be possible, for example, on an exhaust system for motorcycles and, in addition, alone causes only a marginal reduction in the sound pressure and, moreover, even worsens, as in Experiments could determine the engine efficiency compared to a conventional, ie unbranched exhaust system. This phenomenon is explained by the fact that such a parallel ducting is a highly vibratory system, and this is a property that is advantageous for the exhaust ducts that operate on the basis of the production of shaft interference, but is disastrous for the purpose of the present invention is. Because the exhaust system as a whole is naturally very short, especially on a motorcycle, the distance between the primary exhaust pipes directly connected to the cylinder outlets and the pipes of the said arrangement is also short. Since the excitation for vibrations takes place within said arrangement with an engine frequency, ie an ignition frequency, it is possible to superimpose these vibrations with the upstream primary manifold tubes. These overlaps disturb them there the pulse energy of the shock wave taking place at the mouth of the primary manifold pipes is recovered by wave reflection, which uses their pulse energy for the advantageous support of the engine's gas exchange work. Instead, the energy of the shock wave, which induces the opening of a cylinder outlet in a primary manifold tube, is assimilated in the overlays, resulting in the amplification of residual standing waves.

The activation of a "characteristic impedance" in the exhaust system, as described, for example, in US Pat. No. 4,206,177 A, is known to have at most a negligible influence on the noise emission and, based on experience, does not change the resonance behavior of an exhaust system. In motorcycle engines, which usually have a large valve overlap, the installation of a catalytic converter body in the connecting pipe between the exhaust manifold and the muffler often leads to discrete performance drops in certain speed ranges. The reason for this is that on the front of a catalytic converter, which usually consists of honeycomb cells, the shock waves emanating from the engine experience total reflection and run back as an overpressure pulse to the cylinder, where they interfere with the gas exchange.

The proposed constructive connection of the features of the division and subsequent reunification of the exhaust gas flow with a downstream wave resistance, which is however in front of the actual silencer, not only avoids any negative influence on the engine efficiency due to unfavorable vibration superposition and returning (overpressure) shock waves, but causes In addition, an internal sound attenuation within the presented arrangement by 3 db (A), thus halving the sound pressure before the actual silencer. The proposed switching of a medium immediately after the union of the parallel pipelines, the passages of which allow the exhaust gas volume flow to pass unhindered, but are so small that they force impinging shock waves to a total reflection, such as a finely perforated sheet metal or a catalyst body , causes in comparison to the arrangement from EP 0 421 724 A1 Exponential multiplication of the amount of pulse energy, which is bound in mutual partial reflection between the ends of the parallel pipes 9 and 10 in the arrangement: Because the switching of such a medium immediately after the unification of the parallel pipes leads to total reflection of all occurring shock waves, including the partial waves , which result from the undivided shock wave before the arrangement in the collecting tube 7, ie the split waves and their countless derived, often (partially) reflected secondary waves and, due to the partial character of the wave reflection at the ends of the tubes 9 and 10, the direction of propagation of the original wave. This exponential multiplication of partial waves, which are derived from the original shock wave, which due to the total reflection at the wave resistor 12 is fed to the interplay of partial wave reflection in the upstream pipe arrangement, causes a corresponding multiplication of Carnot's shock losses and consequently an exponentially increased conversion of wave energy in heat in the course of partial reflections. This not only explains the efficient reduction in sound pressure of the proposed arrangement, but also realizes a further advantage of our invention: the intensification of Carnot's shock losses results in independent internal heating of the exhaust gas immediately upstream of a catalytic converter, but not, as is customary in known catalytic converter arrangements, in the Stagnation point on its front surface. In this way, the catalytic converter body, even if it is placed comparatively far from the engine, quickly reaches operating temperature after the engine has been cold started, but without overheating under full load operation.

The exponential multiplication of each individual shock wave that occurs in the proposed arrangement, which occurs when a cylinder outlet is opened, into a large number of sub-waves also effectively excludes any vibration overlaps with the upstream primary manifold pipes of the exhaust system, at the mouth of which, as is known, generated the ignition frequency of the engine , Shock waves experience an advantageous (partial) wave reflection because they optimize engine efficiency. The reason for this lies not only in the already mentioned processing of the impulse energy of the shock waves Likewise, suggestion for any residual standing waves is reduced, but essentially in that the exponential splitting and division of the original wave into a large number of sub-waves is accompanied by a similar multiplication of the natural frequency of a standing wave, which is caused by these sub-waves experience their suggestion. In this way it is ensured that the fundamental frequency of vibrations from said arrangement is significantly above the ignition frequency of the engine to which the exhaust system is connected, as a result of which undesired superimpositions and resonances are avoided.

Fig. 2 shows an arrangement according to the invention in which two exhaust silencers 14 and 14 'are coupled to the connecting pipe 7 on the branch 8 by the branch 8 having the exhaust gas flow on two pairs of parallel pipe sections 9 and 10 or 9' and 10 ' each subordinate devices 11 to 13 or 11 'to 13'.

A constructive alternative to two separate, parallel pipes in the arrangement according to the invention is shown in Fig. 3 and its cross section A-A. Here, the parallel guidance of the exhaust gases is now ensured instead of in pipe sections 9, 10 by only one pipe, the cross-sectional area of which preferably corresponds to that of the collector pipe 12 or whose continuation it is. This pipe is divided by a partition plate 15 into two channels through which the exhaust gas must flow. The wave resistance 13 is placed at the end of these channels, advantageously as previously described, in the center of the pipe 12, to which the muffler or catalytic converter 14 is connected in the usual way.

In an arrangement such as that of FIG. 3, the function of the branch 8, which divides the exhaust gas from the connecting pipe 7 onto the channels defined by the separating plate 15, is preferably carried out by a conical extension piece which has the cross section from that of the connecting pipe 7 to the Cross section of the manifold 12 expanded.

Fig. 4 shows a particularly favorable embodiment of an arrangement according to the invention, wherein the two secondary exhaust pipes 5 and 6, which each pass the exhaust gas of one cylinder or a cylinder group of an engine together and between which a connection 15 can optionally be provided, each have a wave resistance 13 or 13 ' it is assigned downstream silencer 14 or 14 '. In this case, downstream lines 9 and 10 or 9 'and 10' are connected downstream of the branch 8 or 8 'in such a way that the exhaust gas flow of the tubes 5 and 6 is divided into both wave resistances 13 and 13' and sound absorbers 14 and 14 '. This additional division in the exhaust gas routing brings about a new increase in efficiency of the proposed arrangement in the processing of the pressure wave energy, since the wave components from the lines 9 and 10 or 9 'and 10', which are subsequently totally reflected on the wave resistance 13 or 13 ' , wave reflections are supplied by the circuit implemented here both in tap 8 and in tap 8 '.

Claims:

Claims

Claims:

1. Collector pipe arrangement for exhaust systems of internal combustion engines, in particular multi-cylinder motorcycle engines, for switching between the exhaust gas outlet lines from the or each cylinder and at least one muffler (14), the exhaust gas outlet lines of the cylinders eventually being gradually integrated into a connecting pipe (7 ) are summarized, a branch (8) is provided behind this connecting pipe (7), which branches the exhaust gas flow onto at least two separate, flow-parallel pipes (9, 10; 9 ', 10') with a larger cross-sectional area than that of the connecting pipe (7), and behind these pipes (9, 10; 9 ', 10') a junction (11, 11 ') is again provided on a single header (12, 12'), characterized in that the header (12 , 12 ') has a free flow cross section which corresponds at least to the total area of the parallel pipelines (9, 10; 9', 10 '), and that in di esem collecting tube (12, 12 ') a component (13, 13') is used as a wave resistance, which component (13, 13 ') allows the exhaust gas volume flow to pass unhindered, while pressure waves are forced to give the most complete possible reflection on this component .

2. Arrangement according to claim 1, characterized in that the total cross-sectional area of the parallel pipes (9, 10; 9 ', 10') is at least 25% larger than the free flow cross section of the connecting pipe (7), preferably 40% to 60% greater.

3. Arrangement according to claim 1 or 2, characterized in that the length of the parallel pipes (9, 10; 9 ', 10') corresponds to at least twice the respective diameter of these pipes.

4. Arrangement according to claim 3, characterized in that the connecting tube (7) is designed as a connecting member between the upstream outlet tubes (1 to 4, 5, 6) and the arrangement according to the invention with a tube length which is at least the diameter of said tube (7th ) corresponds.

5. Arrangement according to one of the preceding claims, characterized in that the parallel pipes (9, 10; 9 ', 10') are formed as adjacent pipe sections with substantially parallel axes.

6. Arrangement according to one of the preceding claims, characterized in that more than two, preferably three parallel pipes are provided.

7. Arrangement according to one of the preceding claims, characterized in that the wave resistance (13, 13 ') is designed as a plate provided with holes or slots.

8. Arrangement according to claim 7, characterized in that the wave resistance (13, 13 ') is designed as a substantially axially parallel oriented perforated plate cylinder, the parallel pipes (9, 10; 9', 10 ') facing end is closed, while the the other end to the downstream parts (14) of the exhaust system, in particular the silencer, is open.

9. Arrangement according to claim 7, characterized in that the holes or slots have a non-negligible longitudinal dimension or are axially extended by short pipe sections or protuberances of the sheet.

10. Arrangement according to one of claims 1 to 6, characterized in that the wave resistance (13, 13 ') is a catalyst body with, for example, honeycomb shafts.

11. Arrangement according to one of claims 1 to 6, characterized in that the wave resistance (13, 13 ') is a porous metal or ceramic body, preferably made of sintered material.

12. Arrangement according to one of claims 1 to 6, characterized in that the wave resistance (13, 13 ') is a scrim, knitted fabric or knitted fabric made of metal threads.

13. Arrangement according to one of claims 7 to 12, characterized in that the total cross section of the passage openings in the wave resistance (13, 13 ') is larger than the total cross section of the parallel pipes (9, 10; 9', 10 ').

14. Arrangement according to claim 13, characterized in that the total cross section of the passage openings is approximately 30% to 40% larger than the total cross section of the pipelines (9, 10; 9 ', 10').

15. Arrangement according to one of the preceding claims, characterized in that the wave resistance (13, 13 ') is arranged directly behind the junction (11, 11'), the distance to the end of which is at most approximately twice the pipe diameter there.

16. Arrangement according to one of the preceding claims, characterized in that at least two taps (8, 8 ') and at least two junctions (11, 11') are provided parallel to one another, the pipelines (9, 10 and 9 ', 10 ') of each branch (8, 8') to different mergers (11, 11 ').

7. Arrangement according to claim 16, characterized in that at least one connection (15) between the parallel pipes (5, 6) is provided in front of the or each branch (8, 8 ').