DE2747655A1 - Internal combustion engine exhaust system and silencer - uses tubes with multiple bores to cool exhaust gas - Google Patents

Abstract

A silencer forming part of the exhaust system of an internal combustion engine consists of two concentric tubes (51, 52). These tubes are joined by radial walls (55) which extend longitudinally so that the annular space between the tubes is divided into a number of separate compartments (5). A cooling fluid flows in these compartments (5) in the opposite direction to the flow of gas in the central bore (50). The outer wall of the outer tube (52) has a number of radial fins (56) which also extend longitudinally. These fins help to dissipate the heat which has been transferred to the cooling medium by convection and radiation.

Description

Additional application to patent application P 27 33 443.6 (lei S 7710)

Designation of the additional application: "Thermal exhaust gas addition 8".

Description In the patent application P 27 33 443.6 was in the Usually extruded Hohlkommerringrohr described, which is made of aluminum is and in compliance with certain thermal rules for the gas £ 59hPung in muffler or cooling sections or other final parts of exhaust systems is integrated. These Rules initially see a certain construction of the elongated aluminum body before: a pipe-like or profile-like inner line (so-called central line) is led by a Surrounding shell space, which is divided into a plurality of elongated channels by ribs is. As these ribs and the inner tube represent a uniform extruded body, a constant flow of heat between the inner pipe and the partial flow channels is ensured, for whose direction the construction of the overall system is decisive and from the answered whether in the inner pipe or in all or some of the sub-channels a relative cooler amount of gas (exhaust gas or air or a liquid medium) is moved. The organization the media flowing through depends in turn on the constructive peculiarities of the two Shear body from, which can be dismantled on both probes of the extruded part are and with which the feed, distribution and discharge concepts in relation to the enforced media are related. The patent claim of P 27 33 443.6 went on the assumption that the outer wall of the Hohlkommermantels radiates into the open atmosphere and the further feature that the amount of gas which the first aluminum pipes, which radiate with their walls into the free atmosphere, extends in front of the re-entry into aluminum-limited channels passes a thermal intermediate zone, in which a further loss of heat, for example through a heat exchange wall, is provided is. The special technical point of view of the construction presented with P 27 33 443.6 consists in its characteristic part now in "that within the between Engine exhaust and first exposure of aluminum walls located exhaust gas inlet zone Heat exchange wall to a downstream of the first exposed one Aluminum gas ducts located device outlet pipe or its supply lines is provided. "Es This arrangement creates a so-called thermal short-circuit path between the hot gas inlet zone of the device and the device outlet line and thereby the effect that the on The amount of heat carried out in this way skips the aluminum component and thereby adds another technical aspect that enables the device to be loaded with a hotter exhaust gas than it is according to the theory of high-temperature strength limits this material would be required.

The attached schematic drawings Figures 1 and 2 both show the construction of the thermal short-circuit path described above.

In both cases, the exhaust gas inlet zone 2, to which the engine exhaust pipe 1 is connected directly or indirectly, a heat exchange wall 5, which is part of of the supply line, that is to say of the space 21, from which the exhaust gas via the Tubes 11 is fed to the free atmosphere. The outlet pipe is in Figure 1 Tube 13, in Figure 2 the partial flow bundle of tubes 24. Meanwhile, in the application P 27 33 443.6 no aluminum walls at all on this thermal short-circuit path more were touched, the exhaust gas passes through after exiting the pipes 11 into the Figures 1 and 2 the aluminum-limited central tube part 10. For this reason in particular it was useful, in addition to the heat reduction through the thermal energy described overleaf Intermediate zone ", that is to say the closing body space 19 of FIGS. 1 and 2, another heat to provide for lowering. This consists in a repeated passage of the amount of exhaust gas through one or more partial flow channels of the provided in the shell body, into the EanalbUndels radiating a free atmosphere and usually ribbed on the outside. As As can be seen from the schematic drawings, the exhaust gas emerges from the first expansion space 2 into several channels 9 of the extruded part, then opens into the closing body space 19 and enters from this through the openings 17 again one or another Group of partial flow channels 16 which - as a rule, alternately - the partial flow channels 9 are adjacent. The channels 16 are closed downstream by the closing body 4 and the exhaust gas passes through an overflow opening 15 which is located in the aluminum walls 20 is located via a corresponding opening 7 in an additional channel 21 over, the one with insertion depth in the space 10 of the aluminum body part of the upstream Closing body is. In the jacket wall of the extruded aluminum part in this way there are two gas flow groups arranged in countercurrent to one another, of which the following (16) is cooler compared to the previous (9), namely once after the long way through the aluminum wall parts of the channels 9 as a result of their Ab beam losses, on the other hand due to the radiation loss from the collecting space 19 for which it is a mere design question how large its outer surface is kept. In addition, at the same time the heat dissipation path from the wall 20 of the inner line 10 was atimated, since now with the help of the gas streams 16 a greater heat gradient Direction outer wall 8 has arisen.

Should, despite this measure, the aluminum temperature be at certain Motor types and sizes approach the upper heat resistance range, is shown in the figure 2 reinforcement of the thermal short-circuit path for this compensation. It will an Innenkishlrohr 22 arranged, as it is on the part of the applicant in the Offenlegungsschriit 25 10 624 has been described. This one, which is fundamentally different from the exhaust gas flow The air flow-aiming pipe can then be used as an inner line in an outlet pipe continue, in the inner line 23, while the exhaust gas outlet through the partial flow bundle 24 takes place. For idling conditions in which there is no driving wind is given, an exhaust gas injector with the direction of the device outlet can be provided in the pipe part 22 be. The inner cooling pipe runs through both the first hot gas space 2 and in FIG the collecting space 21; its thermal relief of the inner wall 20 of the aluminum extrusion is therefore not only from its passage through the room 10, but in particular from the primary heat dissipation from the inlet chamber 2 to be assessed.

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Claims (7)

Claims 9 Thermal exhaust gas flow using the extrusion process manufactured aluminum-manufactured component of a hollow chamber ring tube, which is in Integrated silencers or sections of the exhaust systems of internal combustion engines is and by ribs in particular with regard to its shell space in elongated, is divided around a central line arranged partial flow routing groups, with the feature that the outer wall of the hollow chamber jacket into the free atmosphere emits, the feature that the amount of exhaust gas that the first aluminum Eanalfuhrung leaves one before entering a second channel guide group of the extruded part thermal intermediate zone, in which it suffers further heat loss, and the further iIerkmn1 that within the between the Notorauslaß and the first vent from aluminum walls located pre-zone (2) heat exchange wall (5) to a downstream the first aluminum line (9) located supply line (21) to the device outlet pipe (13, 24) st, dodurcli marked that the 'Ogh9 comes from a first aluminum-limited partial flow group (9) in the by a closing body (14) of the Extruded part (8/20) formed collecting space (19) passes from which it is in a another partial flow group or at least one gas duct (17/16) reaches, which is also within the Hohlksmmermanteltaumes of the extruded part is located and in a countercurrent arrangement at least partially adjoins walls, which On the other side to the partial flow group (9) to which the first act is applied or to form the central line (10) belong. 2. Device according to the previous claim, characterized in that the second partial flow group (16) merges into a collecting space (21), which heat exchange wall (5) to the hot gas inlet zone (2) of the device and with penetration depth in the central line (10) of the extruded part is part of the upstream closing body of the aluminum extrusion. 3. Device according to one of the preceding claims, characterized in that that the central line (10) of the extruded part passes through an internal cooling pipe (22) in which an air throughput that is different from the exhaust gas flow takes place. 4. inner cooling tube according to the previous claim dadurc'n characterized in that it also penetrates the hot gas inlet zone (2) and other intermediate volumes (such as 21). 5. Inner cooling tube according to one of the preceding claims, characterized in that that it is in the central line (23) designed as a hollow-chamber jacket tube Outlet pipe continues, through the outer partial flow group (24) of the exhaust gas outlet takes place. 6. Innenkishlrohr according to one of the preceding claims, characterized in that that an exhaust gas injector is arranged upstream, which extracts the exhaust gas from the central line (10) of the 3trangpreßteil decreases. 7. Device according to one of the preceding claims, characterized in that that the closing body, which on both sides the inlet arrangement including the Determine distribution and discharge concepts by means of an axially extending clamping device are connected.