Characteristic:
Advanced performance of catalyst, wide range of three-way window, high conversion effciency.
Excellent performance of temperature, space velocity and A/F ratio. Low loading of precise metal and high performance/price ratio.
Uniformly covered by catalyst, frm, rustproof, steady.
Brilliant endurance can meet the emission standard of EURO 3 and more strict emission standard.
Characteristic: conventional pollutants are HC, CO,NOx, the temperature of exhaust gas is above 1000?, the HGSV>100000h-1, high vapor concentration(about 10%), high sulfur condition(SOx), so the catalytic reaction condition is very rigorous, under such circumstance the catalyst is required actively and endurance for 100,000KM with low loading of precious metal.
(1)Close-coupled catalyst(CCC): also named Close-coupled catalyst, it is assembled and closed to the engine in order to increase the conversion effciency of HC in lower temperature, the function is to stabilize the activation under water vapor condition, sulfur-poisoned and high-temperature sintering resistance(still working within the temperature 800?1050?)
(2)Three-way catalyst: it is assembled in the middle of chassis to convert the CO,HC, NOx , the function is to stabilize the activation under water vapor condition, sulfur-poisoned, wide window temperature can solve the conversion efficiency drop when A/F fuctuate a lot.
Composition:
? Substrate: ceramic honeycomb or metal honeycomb
? Supporter: rare-earth oxygen-storage material
? Promoter: ZrO2,La2O3 and so on
? Active components: Pt, Pd, Rh and so on
The catalytic reaction theory of exhaust purge
HC+O2 ? CO2+H2O (1)
CO+O2 ? CO2 (2)
NO+CO ? N2+CO2 (3)
NO+HC ? CO2+N2+H2O (4)
NO+H2 ? N2+H2O (5)
CO+H2O ? CO2+H2 (6)
HC+H2O ? CO+H2 (7)
