AT414294B - EXHAUST GUIDE TO A COMMERCIAL VEHICLE - Google Patents

Description

2

AT 414 294 B

The invention relates to the exhaust system in a commercial vehicle with an internal combustion engine with V-shaped cylinder banks, the exhaust ports each lead to a cylinder bank in a common exhaust manifold and the internal combustion engine, together with a flanged to the engine transmission, between two 5 longitudinal beams of a chassis frame Commercial vehicle is arranged so that the exhaust manifolds extend above the longitudinal beams and wherein a lying below the longitudinal beams exhaust aftertreatment system is provided which comprises at least one hydrolysis and downstream of this one SCR catalyst. In today's conventional diesel internal combustion engines for commercial vehicles, it is necessary for reasons of environmental compatibility to limit the proportions of nitrogen oxides to a minimum. For this purpose, exhaust gas aftertreatment systems are provided, which inject aqueous urea solution into the hot exhaust gas upstream of a hydrolysis catalytic converter arranged in the exhaust gas line, which is then converted into ammonia in the hydrolysis catalytic converter. Downstream of the 15 hydrolysis catalyst, a so-called SCR catalyst is provided, which causes the actual reduction of the nitrogen oxides (NOx) with the aid of the ammonia produced in the hydrolysis catalyst. Such systems are e.g. known from DE 40 38 054 A1.

In replacement of the freezing at temperatures below -11.5 degrees Celsius and thus in the Ver-20 turn problematic aqueous urea solution, it is also known ammonia carrier in solid form z. B. solid urea, which is the upstream of a corresponding hydrolysis catalyst fed to the exhaust gas stream. Such a device is described for example in DE 102 52 734 A1. It is finally known from DE 101 23 359 A1 to arrange the hydrolysis catalytic converter in the front silencer and the SCR catalytic converter in the main silencer of an internal combustion engine.

For thermal reasons, the above-mentioned Abgasnachbehandlungssyste-30 me as close to the exhaust manifold of the internal combustion engine to be arranged.

In commercial vehicles, especially those with high performance, it is common to use internal combustion engines with V-shaped arranged cylinder banks. In these internal combustion engines, the exhaust manifolds usually run up to the outsides parallel to the Zylin 35 derbänken. There, however, is very limited in the installation of such an internal combustion engine in a commercial vehicle, especially a truck, the available space, especially when the internal combustion engine, as is common today, has turbocharger for charging. An accommodation of hydrolysis catalysts in this area is therefore extremely problematic, especially if they are integrated in an advantageous manner in pre-muffler. A thermally favorable housing of hydrolysis catalysts in commercial vehicles of the type described above is further counteracted that the internal combustion engine is usually arranged on a support frame, wherein the exhaust manifolds extend above the longitudinal beams of the support frame, the muffler, however, lie in a plane below the longitudinal beams. In hitherto conventional constructions without exhaust aftertreatment, the exhaust pipes 45 have been guided downwardly around the longitudinal spars, but this is for arrangements in which the hydrolysis catalyst is in a plane below the longitudinal spars, e.g. is arranged in the pre-muffler, thermally very unfavorable and claimed in the area in which the exhaust pipes lead past the longitudinal beams, relatively much space. Thus, starting from the above prior art, it is therefore an object of the invention to provide an exhaust system that allows a favorable thermal connection of the hydrolysis and minimizes the space required for the exhaust pipes.

The object is achieved by the characterizing features of claim 1, advantageous embodiments 55 of the invention are characterized in the dependent claims. 3

AT 414 294 B

The solution of the problem provides that the above lying above the chassis frame exhaust manifolds are each connected via a turbine of an exhaust gas turbocharger with exhaust pipes, each leading between the longitudinal beams and flanged to the engine gear down and open into a arranged below the longitudinal beams pre-muffler in which the hydrolysis catalytic converter and at least one oxidation catalytic converter are integrated and which is followed downstream by a main silencer with at least one integrated SCR catalytic converter. Through this exhaust system ensures that the distance between exhaust manifold and hydrolysis catalyst is bridged by the shortest route and with minimal space stress.

To improve the thermal connection of the hydrolysis catalyst, it may also be advantageous to insulate the exhaust pipes at least in the region between the longitudinal spar and the transmission, so that the insulation on the one hand minimizes the heat loss of the exhaust gas and on the other hand the function of a heat shield to the transmission or the respective longitudinal spar takes over.

Examples of the invention and advantageous embodiments are explained in more detail with reference to the drawings.

Show it:

1 is a built-in commercial vehicle internal combustion engine with flanged gear and exhaust tract in plan view from above Fig. 2 shows the arrangement of Fig. 1 in side view

A common in commercial vehicles arrangement of engine and transmission is shown in Fig. 1 in plan view of the arrangement and in Fig. 2 in side view. Identical components are each provided with the same reference numerals.

The internal combustion engine 1 shown has two V-shaped cylinder banks 2.1, 2.2. The outlet channels (not shown) of the cylinder banks 2.1, 2.2 are connected via exhaust manifold 3.1, 3.2 with exhaust manifolds 4.1, 4.2. In internal combustion engines of this type, the exhaust manifolds 3.1, 3.2 and the exhaust manifolds 4.1, 4.2 are usually each right and left of the longitudinal axis of the internal combustion engine in its upper region. The exhaust manifolds 4.1, 4.2 are connected to the inlets of turbines 5.1, 5.2 of turbochargers 6.1, 6.2, which act on the compressor of the turbocharger 6.1, 6.2. The outlets of the turbines 5.1, 5.2 open into exhaust pipes 7.1, 7.2, which in turn open downstream into a pre-muffler 8, which in turn is connected downstream with a main muffler 13.

In the pre-muffler 8 are, in addition to a feeder 11, by means of an external to the pre-muffler metering device 12, the reducing agent, for. As aqueous urea solution, feeds, a hydrolysis catalyst 10 and a z. B. consisting of two modules oxidation catalyst. In the main muffler 13 an existing example of five modules SCR catalyst is integrated.

Flanged to the internal combustion engine 1, a gear 16 is shown in Figures 1 and 2. The combination of internal combustion engine 1 and transmission 16 is in a chassis frame of a commercial vehicle, e.g. of a truck, of which the two longitudinal beams 15.1, 15.2 are shown in Figures 1 and 2.

In the mounting situation common in trucks, the exhaust manifolds 4.1, 4.2 and 5.1, 5.2 turbines are above the longitudinal beams 15.1, 15.2 of the chassis frame, while the pre-muffler 8 and the main muffler 13 below the longitudinal struts 15.1, 15.2 are arranged.

Claims (2)

4 AT 414 294 B For connecting the outlets of the turbines 5.1, 5.2 located above the longitudinal beams with the underlying pre-muffler 8, the exhaust pipes 7.1, 7.2 are arranged so that they from the turbines 5.1, 5.2 each down, between the gear 16 and the respective adjacent longitudinal beam 15.1, 15.2 and then lead to the rear, where they are brought together in the pre-5 silencer 8. To shield the transmission against inadmissible heat radiation, and to shield the exhaust gas against heat loss, the exhaust pipes 7.1, 7.2 may be provided with an insulation 20.1, 20.2. The isolation of the exhaust pipes 7.1, 7.2 against heat loss can therefore io be necessary because the exhaust gas would cool too much on the route between the turbines 5.1, 5.2 and the hydrolysis catalyst 10 and so the implementation of z. As aqueous urea solution in ammonia, for which high exhaust gas temperatures are required, could not be done in the necessary manner. On the one hand, the shielding of the heat-sensitive regions of the vehicle and, on the other hand, the protection of the exhaust gas from excessive heat loss on the way to the hydrolysis catalytic converter, can be ideally combined by the chosen design. Reference is made to the publications mentioned in the introduction to the description of the exhaust gas after-treatment chemical processes. Of course, the above-described embodiments can be embodied in a variety of ways with expert knowledge that is accessible to the person skilled in the art, without departing from the basic inventive idea; thus, these embodiments are given only exemplary character. 1. Exhaust system in a commercial vehicle with an internal combustion engine with V-shaped arranged cylinder banks, the exhaust ports each a cylinder bank (2.1, 2.2) in a common exhaust manifold (4.1, 4.2) open and the internal combustion engine (1), together with a to the internal combustion engine (1) flanged gear (16) between two longitudinal members (15.1, 15.2) of a chassis frame of a commercial vehicle so 35 are arranged, that the exhaust manifolds (4.1, 4.2) above the longitudinal beams (15.1, 15.2) extend and wherein a below the exhaust gas aftertreatment system (15.1, 15.2) is provided which comprises at least one hydrolysis catalytic converter (10) and downstream of it an SCR catalytic converter (14), characterized in that each exhaust gas collector tube (4.1, 4.2) is connected at its end to the inlet each least-at least one turbine (5.1, 5.2) of at least one exhaust gas turbocharger (6.1, 6.2) is connected, the turbine (5.1, 5.2) downstream of jewe ils an exhaust pipe (7.1, 7.2) is connected, the down, between each one longitudinal spar (15.1, 15.2) of the chassis frame and the transmission (16) through to a below the longitudinal beams (15.1, 15.2) of the chassis frame arranged two cylinder banks (2.1 , 2.2) common pre-silencer (8) leads, internally a hydrolysis catalyst (10) and at least one Oxida tion catalyst (9) and the downstream of a main silencer (13) with at least one integrated SCR catalyst (14) follows. 2. Exhaust system according to claim 1, characterized in that the exhaust pipes (7.1, 7.2), so at least in the area in which they lead between the transmission (16) and the longitudinal members (15.1,15.2) of the chassis frame, are thermally insulated. For this 2 sheets of drawings 55