Surface and coatings effects in catalytic combustion in internal combustion engines

Abstract

Various aspects of catalytic combustion relating to engines have been investigated. MoO 3 and coatings of transition metal oxides (prepared by flame pyrolysis) were confirmed to have combustion catalytic activity commencing at ~325–430 °C. Evidence from experiments and the literature indicates that in-cylinder catalysts can aid in fuel ignition (beneficial), but may also cause early quenching of the flame-front (detrimental) at combustion chamber surfaces. Catalytic combustion, when it occurs on thermocouple or heat probe surfaces, will cause surface temperature measurements in furnaces or engines to be erroneously high. This may explain the Woschni effect, a controversial finding wherein thermal insulation (which raises combustion chamber wall temperatures) appears to increase heat rejection from the combustion chamber.