DE675355C - Exhaust system for internal combustion engines - Google Patents

Description

Exhaust systems for internal combustion engines The present invention relates focuses on the catalytic cleaning of exhaust gases and has a Device for better implementation of the afterburning in catalyst filters. It consists of a large surface area connected in front of the actual filter room Chamber, which has the task of once the heat of the combustion gases leaving the filter to the colder exhaust gases flowing to the filter, transferred and simultaneously to allow these exhaust gases to expand before they enter the filter, @ so that the pressure waves and shock effects present in the gases cancel each other out and the gases can enter the catalyst in a steady flow.

Maintaining the highest possible catalyst temperature is required in all engine states, especially at low loads and speeds to achieve the best possible afterburning in the filter. One has already tried by preheating or throttling the intake air of the engine or to raise the catalyst temperature with the help of an external heating source. In the The present arrangement is that obtained by the afterburning in the filter itself Heat used to preheat the gases going to the filter by removing them Transferring heat to the surface of a chamber upstream of the catalyst will. On the other hand, it is to avoid severe mechanical wear and tear on the catalytic converter required, the pressure waves and gas oscillations occurring in the exhaust Expansion of the gases in a space upstream of the catalyst with relative To dampen narrow inlet and especially outlet openings and the gases as possible to allow balanced flow to reach the filter.

Both tasks, that of heat transfer and that of shock wave compensation, are fulfilled by a preheating and compensation chamber arranged in front of the filter, as described below.

Fig. Ra shows an exhaust filter with antechamber, the latter with A denoted. net is. In detail, the same consists of a sheet metal jacket B and two floors C and D; -which each have a relatively narrow opening E or F for the gas inlet or outlet. The outer jacket B, the cross-section of which can be seen from XX from Fig. Rb, is provided with more or less deep and numerous folds, waves or the like G so that the chamber is in contact with the surrounding space H over a large surface. After passing through the chamber, the gases enter the actual filter in a quieter flow at F and flow from the central tube J, which consists of perforated sheet metal or wire mesh, radially through the catalyst mass I (, the catch plate L ensuring that the Path of the gases is the same at all points of the annular jacket layer. They are then conducted in the opposite direction in the annular space M along the outside of L and then distribute in the outer space H between the folds of the preheating chamber to transfer their heat to the inside The gases flowing from the chamber to the filter are released and finally they leave the filter through line N.

Instead of longitudinal folding, the chamber can of course also be folded transversely in accordance with Art the arrangement shown in Fig. z. The individual chamber elements exist here made of round metal sheets also provided with a round opening, each of which are connected to one another with their inner and outer edges P and Q, respectively.

Finally, the chamber can also be used as a round tube of any kind Form diameter, glass on its circumference with longitudinal or transverse ribs made of smooth or perforated sheet metal to mediate the heat transfer is provided.

The relationship between the space of the chamber and the space surrounding it Outside space can be anything. If you put more emphasis on balancing the pressure waves, it is advantageous to make the interior as large as possible. On the other hand, should the If preheating is complete, the surface must be formed by strong and deep waves be made as large as possible.

If the spatial conditions on the car require it, you can Chamber, instead of accommodating it with the filter in a common sheet metal jacket, also disconnect from the filter and then the connection between the chamber and the filter and the return of the gases coming from the filter to the outside of the chamber arrange appropriate pipelines.

If you finally change the filter shape by z. B. instead of one The ring filter selects a flat filter surface, from the gases from top to bottom is flowed through, the antechamber must also assume other forms, which result from the analogous transfer of the idea of the invention easily result. You will then about a flat vestibule above or below the filter surface or one place the appropriate space in front of it and the space intended for heat transfer Also provide the surface with wave formations.

Claims (1)

PATENT CLAIM: Exhaust system for brake engines with catalytic acting exhaust filter together with antechamber, characterized in that in front of the filter a large-area antechamber (A) with a relatively narrow inlet and outlet opening is arranged to give the exhaust gases an expansion before they enter the filter for the purpose of balancing the pressure waves present in them and their Outer jacket flushed by the combustion gases leaving the filter for the purpose of preheating of any cross-section with any wave or fold formation or with any heat transferring ribs made of smooth or perforated sheet metal is.