AIChE Journal, Vol.44, No.1, 184-187, 1998
Novel concept prototype of low-power-consumption electrically heatable catalyst
Electrically heated catalyst devices (EHCs) are important for treating exhaust gases in the 20 to 120 s warmup period after a cold start when about 70% of the total hydrocarbon (HC) and carbon monoxide (GO) Emissions from a modern gasoline powered vehicle are released. Although known for several years, EHCs have not been deployed because these devices are cost- and energy-intensive. An alternate EHC prototype proposed here is based on our reasoning that only the platinum group metals and the molecules undergoing oxidation need to be at light-off temperatures and it is not necessary to waste energy to heat the whole catalyst. The concept prototype, fabricated on a glass coupon, resistively heats the fluorine doped tin oxide film beneath the washcoat to bring a palladium-titania washcoat to the CO and HC light-off temperatures. The electrically powered concept prototype showed light-off temperatures of 250 degrees C and 260 degrees C for CO and HC, respectively, in laboratory tests with simulated exhaust gases at 25 degrees C. A device based on this concept is estimated to attain the 1-kW target power consumption required for the deployment of the EHC.