DE2718944A1 - 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 patent application to P 25 10 624.5

Designation: Inner cooling pipe with single and multiple drilling chamber jacket Description In the main application 2 25 10 624.5 there is a description of the flow pipe (or several) used for internal cooling of an exhaust system in three different directions, firstly a description of the position of this pipe containing an air flow rate, secondly a description of the factors , which bring about or promote this air throughput, thirdly, an additional use of the flow pipe as a propellant promoting air turnover for cooling zones that are located outside the sound-absorbing components (claim 3). This additional application describes further improvements and applications of the inventive concept in the above three directions, in particular also for the case provided in the main application that the exhaust system also has the task of exhaust gas conversion for the purpose of removing pollutants in addition to soundproofing. In this construction context, there are special thermal conditions. Since the special structural aspect of this additional notification consists in designing the outer wall of the inner cooling tube with one or more hollow chambers, in particular also from the same material or in a combination of different materials, not only equipping the jacket of a gas guide space with an annular space divided into several hollow chambers, Instead, to arrange several such hollow-chamber annulus spaces in such a way that one wraps itself around the other as a further jacket, knowledge of the thermal conditions within those zones in which this construction system is used is, among other things, a prerequisite for understanding the technological meaning of this construction and the choice of material, which varies from case to case. A description of an exhaust system is therefore first made as an example of the issues within which cooling needs arise. This first leads to a definition of the zones in which these problems occur and then to the technologically sensible measure of using hollow-chamber cooling tubes of a certain shape and certain material properties to solve them. If the system of the so-called THERMIC THREE-WAY RE-ACTORS is chosen as a concrete example, this does not mean that the use of the relevant construction elements is dependent on the use of this exhaust gas conversion system. Since catalytic systems usually reach at least similar temperature peaks, the use of hollow-chamber cooling tubes is also sensible in such cases. TTR system (TESZMIC THRE-WAY REACTOR) 1500 1000: 1 6 500 250 125 Path 1: Numbers 1-5 Path 2: Numbers 6-9 Path 3: Numbers 10-13 Explanation of the scheme. 1 = primary combustion in the engine (essentially between 2000 and 250,000). 2 = temperature at the outlet valve (about 8500).

3 = outlet pipes. 4 = first expansion volume; see section 10. 5 = Cooling section 1 (for untreated exhaust gas. 6 = exhaust gas inlet section to the reactor (again Heat build-up; Heat exchange to cooling section II zone 2 with heat flow from 12 to 6). 7th = Increase in heat build-up (heat exchange to cooling section II zone 1 with heat flow from 11 to 7). 8 = last stage of the exhaust gas and additional air inlet to the reactor (both media with heat exchange to afterburner success rooms and in the pre-stretch area below direct heat radiation from the afterburning chamber 9). 9 = Secondary combustion process in the afterburning chamber up to 100,000 (reverse scavenging combustion chamber, additional air supply through Injector, differentiation between combustion chamber niche with ignition element and full burner sections, Combination of small cold start reactor mass with ceramic storage mass). 10 = Main part of the full burner line with heat exchange to the first expansion volume 4 (T.iärmeflußumkehr: in a cold start from 4 to 9/10, in the thermal steady state of 9/10 in 4). 11 = cooling section II zone 1 (see 7). 12 = cooling section II zone 2 (see 6). 13 = cooling section III (cold air mixing, internal cooling pipe system, fine blasting dismantling and other constructive means).

A review of this scheme makes it clear that the correct sequence of the combined noise reduction and exhaust gas conversion process a compact design challenges, since it is hardly possible in any other way on this side and beyond a heat exchange wall e.g. an exhaust gas inlet zone (6 of the scheme) to bring into a heat exchange relationship with an exhaust gas outlet zone (12 of the scheme). The basic construction element of the with hollow chamber annulus as a jacket zone provided flow pipe creates both for the simultaneously to be mastered Soundproofing effect as for the cooling or heat exchange effect, additional advantages : in terms of soundproofing the advantage of dividing the from the engine exhaust incoming gas balls in a multitude of partial flows acoustically controllable dimensioning effect in terms of heat exchange and cooling problems involved the achievement of larger heat exchange surfaces, since a breakdown into profile-like Gas pipes always bring surface enlargements. But of this is the effect of heat exchange or

The cooling effect is essentially dependent. Will the intensity of the process further supported by the fact that a different choice of material is made from zone to zone, so can both the storage effect as the different thermal conductivity of the individual Material groups are optimally used. Such as applicant's U.S. Patent No. 3,989,469 indicates, the technical advancement is in the solution of the difficult thermal Problems from exhaust gas conversion systems to compact systems for a long time; the one there in such a compact system integrated air throughput with a principle of the exhaust gas flow separate inlet and outlet is in this additional application with the principle idea of the inner cooling pipe, which has a related characteristic, combined. To the inventive concept related to the countercurrent afterburning chamber of this patent a more general version is given with this additional application, which is independent of the underlying exhaust gas conversion system is applicable in any case.

There is also an essential economic moment. With different materials, extremely different properties in terms of thermal conductivity and heat storage effect, newer manufacturing methods have been developed which the wage-intensive manufacturing processes of sheet metal processing are becoming more and more popular Push problem margins. This is especially true for the extrusion process, the for ceramic materials as well as above all for aluminum the production is cheaper Sold by the meter allowed. The single or multi-ring hollow chamber tube is this manufacturing process highly customized and allows for the inexpensive manufacture of closely related ones Partial flow groups, as they are for pure silencers as well as for exhaust gas converters and their combinations are always required. This has the further advantage of that the increasing inclusion of these materials means the use of expensive nickel chromium stems saved and the corrosion problem solves so that the running time limitation of the exhaust systems and the so-called Wexgwerf silencers can disappear more and more.

In the formulation of the claims, the features are constructive Details are defined in principle on the basis of the main application P 25 10 624 and then with increasing difficulty in the subclaims from Single-ring hollow-chamber cooling tube through to multi-chamber tube shown on the application. Attempts have been made to use the terms single-ring and slehr-ring hollow-chamber tube the abundance of applications in purely intellectual terms in the clarity of a to keep mental order. In addition, there is the concept of the annulus (numbered), wherein in principle an annular space divided in the longitudinal direction by hollow chambers is meant. However, this does not have to consist of a component, but As Figure 1 shows, designed from a composite of different materials will. Thus, the figure 1 in its schematic basic representation of one Metal tube (24) onto which a ceramic part (8/3/4) and again a metal tube (15) be threaded.

The number of annular spaces can be arbitrary depending on the design task be expanded. Since the hot zones are usually located in the axial core of the system, In the case of composite materials in the outer annular spaces, the Use of a hollow aluminum tube manufactured in an extrusion process possible; as a rule, this is required in the inner annular space in front of it to arrange the air flow zone.

Figure 2 shows a shape, the air throughput zone entirely in an annular space (9), through which exhaust gas flows, to lay (10).

FIG. 4 is an exemplary embodiment for this. The pressed in Channels 10 (Figure 2) are at the same time holding devices for a whole or in part Tube inserted into the aluminum body, which makes the openings through the jacket wall of the device. The aluminum hollow chamber tube (10) is on an inner tube (13) "threaded". The dismantling of the damper is not shown in the diagram.

FIG. 3 shows the hollow-chamber tube (13/10) as the end tube of a Silencer. The damper shows a partial flow forming element made of ceramic (11/7), the channel guides 7 are formed by the fact that metal walls Ceramic grooves rest. The aluminum hollow chamber end tube is on an inner cooling tube (5) attached according to the main application and the exhaust gas flow through the piling chambers 10.

Claims (13)

Claims t flow pipe (internal cooling pipe) according to the main application P 2510624. with an air throughput that is basically separated from the exhaust gas flow, characterized in that it is a cylindrical or profiled gas guide space wholly or with regard to part of its longitudinal extension with one or more Annular spaces is provided, which in this longitudinal extent different Echlkammern have and the air throughput either in the central line (13) or within one of the raw chamber annular spaces (9, 10) takes place. 2. Ohlkammer cooling pipe according to the previous claim, characterized in that that it is either made from a single material as a single component is (13/10 in Figure 3) or in a combination of several 3 components made of different materials in such a way that their form-fitting concern the various gas ducts (3 example Figure 1: 10, 9) forms. 3. base chamber Eühlrohr according to one of the preceding claims da-- through characterized in that different hollow-chamber annulus spaces are not equal to each other Cover the longitudinal extension and in particular construction-related inlet manifolds are inserted into the zone of the annulus. 4. Hohlka = he-Xühlrohr according to one of the preceding claims, characterized in that that the central line (13/24) is designed as an assembly guide rail for the annular space groups is. 5. Single-ring hollow-chamber cooling tube according to one of the preceding claims characterized in that its central line (13/24) is the continuation of a Represents the inner cooling tube according to the main application and opens into the free atmosphere, while the hollow chambers of the annulus remove the exhaust gas from the end volume of an exhaust system (Silencer or cooling section) to the free atmosphere. 6. Hollow chamber Eühlrohr according to the previous claim, characterized in that that it with its hollow chamber inlet openings (Figure 3: 10j within the end volume (12) is arranged overlapping with partial flow ducts through which the Exhaust gas enters the final volume. 7. single-ring base chamber cooling tube according to one of the preceding claims characterized in that the exhaust gas inlet in several parallel pipes this Art flows in from a discharge feed chamber, while the pipes integrated into these pipes Air flow openings keep their separate inlet and outlet openings. 8. Single-ring hollow chamber Eühlrohr according to one of the previous claims characterized in that one or more hollow chambers (10 in Figure 2) for the air throughput are seen above (10 in Figure 2; Figure 4). 9. Single-ring hollow-chamber cooling tube according to the previous claim, characterized in that that the exhaust gas flows into the annular space charged with air (10 in FIG. 4) (9), whose outer wall radiates into the open atmosphere and only then into the central line (13) arrives after the exhaust gas in a relaxation space (16), the walls of which radiate into the open atmosphere, has undergone further cooling. 10. Single-ring or multi-ring hollow-chamber cooling tube according to one of the previous ones Claims characterized in that its exhaust-gas lines have any Gas duct between those provided for soundproofing or exhaust gas conversion Represent buildings. 11. Two or Nehrring hollow chamber cooling tube according to one of the claims 1 - 4 characterized in that the central line within an afterburning system (13) contains the afterburning space and the annular space 1 is made of a composite stainless steel (24) / Ceramic (8.3) is made. 12. Hollow chamber cooling tube according to the previous claim, characterized in that that the air throughput is arranged in that annulus, the inside at the outermost Annular space adjoins. 13. Multi-ring hollow-chamber cooling tube according to one of the preceding claims characterized in that in the supply lines to individual annular spaces outside The cooling sections located in the building are interposed.