Catalytic Effects of Cr2O3 and PSZ on Gas-Phase Ignition Under Diesel Engine Combustion Conditions 902084
The effect of chromium oxide (Cr2O3) and partially stabilized zirconia (PSZ) surfaces on the gas-phase ignition of hydrocarbon fuels has been studied in a high pressure chemical flow reactor under low heat-loss Diesel engine simulated conditions. Results are presented for propane and n-hexane fuels at 6 and 10 atmospheres and are compared to previously reported results obtained under similar conditions with platinum surfaces.
Thermal enhancement of the gas-phase reactions, as evidenced by the catalytic production of CO and CO2, was found to be negligible for both Cr2O3 and PSZ, where as significant thermal enhancement was observed with platinum.
Chemical enhancement of the gas-phase ignition reactions, as evidenced by an increase in the production of intermediate hydrocarbons, was observed under fuel rich conditions with both Cr2O3 and PSZ. Oxygen was shown to be essential in that no change in the intermediate hydrocarbon concentration was observed under pyrolysis conditions. The relative magnitude of the observed chemical enhancement increases in order from PSZ to Cr2O3 to platinum.
These results indicate that in-cylinder Cr2O3 and PSZ coatings may have a significant effect on the ignition characteristics of low heat-loss Diesel engines.