| 摘要 |
To reduce the activating time span of a three-way catalyst (KAT), in the outflow path of the exhaust gas from an internal combustion motor, a preceding auxiliary catalyst (HK) with a netting structure is at a gap from the three-way catalyst (KAT) to oxidize combustible components in the motor exhaust gas. The generated heat is recovered to raise the temperature of the three-way catalyst (KAT). A further metallized netting structure (NS) is in front of the auxiliary catalyst (HK). An atmospheric plasma discharge is developed in the plasma space (PR) between the two electrodes formed by the netting structures (NS,HK). The atmospheric plasma discharge is a barrier discharge. The gap between the two netting structures (NS,HK) is 5-15 mm. The metallized netting structure (NS) is a drawn metal net, coated with a material which is not electrically conductive, and with a porosity of 50-90%. The netting structure (NS) matches the contour of the auxiliary catalyst (HK). The micro-porous carrier for the auxiliary catalyst (HK) is of a dielectric ceramic oxide material, and it can be dosed with one or more rare earth oxides, The micro-porous auxiliary catalyst (HK) carrier can include active catalyst noble metals with a noble metal content of <= 30%. The plasma discharge is formed by an alternating voltage or pulsed direct voltages. The voltage peaks of the alternating voltage or pulsed direct voltage are at a maximum of 15 kV, and the pulse sequences are over 50 HZ and below 100 kHz. Secondary air (SL) is fed into the exhaust gas flow before it reaches the netting structure (NS).
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