Umicore Ag & Co Kg

Juergen Gieshoff

Thomas Kreuzer

Martin Votsmeier

Lino Guzzella

Hartmut Finkbeiner

Roman Moeller

A stream of exhaust gases from the combustion of hydrocarbon-containing fuels with a variable temperature can be produced by dividing the exhaust gases into two separate part-streams, cooling one part-stream and then combining the two part-streams again. The temperature of the exhaust-gas stream which has been combined again can be set to between the temperature of the combustion of the hydrocarbon-containing fuels and the temperature of the cooled exhaust-gas part-stream by corresponding throttling of the two part-streams before they are brought together again. The exhaust-gas stream produced in this way is preferably used for the defined ageing of automotive exhaust catalysts. In this context, it is particularly advantageous that the change in the temperature of the exhaust-gas stream has no influence on its air/fuel ratio.

Method for producing a stream of hot combustion exhaust gases at a settable temperature, apparatus for carrying out the method and use of the combustion exhaust gases for the targeted ageing of catalysts

The invention describes a method for determining the light-off temperature of a catalytic converter on board a vehicle. The aging condition of the catalytic converter is determined by means of the method. To test the catalytic converter, the latter is loaded for example with a CO/HC test pulse. During the combustion of the additional CO and HC on the catalytic converter, an axial temperature profile is generated. The position of the maximum of said temperature profile along the catalytic converter is dependent on the current light-off temperature. The temperature profile travels through the catalytic converter and can be measured at the outlet of the catalytic converter as a time-dependent profile. The original axial temperature profile can be inferred from the time-dependent profile. Using a calculation program, the current light-off temperature of the catalytic converter on the vehicle can be determined. The method has the advantage that the test can take place at exhaust-gas temperatures considerably higher than the light-off temperature. In this way, it is ensured that the test pulse does not lead to increased pollutant emissions.

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Gelnhausen, Germany

Juergen Gieshoff