Research Projects

Advanced low temperature combustion (LTC) modes in compression ignition engines offer unique opportunities to reduce engine-out NOx and soot emissions, but they also produce high total hydrocarbon (THC) and CO emissions. To develop LTC-specific exhaust after-treatment systems, effective and optimized after-treatment systems and system integration issues are needed. Diesel oxidation catalysts (DOCs) are well-established in terms of chemical kinetics and conversion efficiency, but commercially available 1-D simulation tools are expensive and limited in modifying kinetic parameters. LTC modes have different exhaust temperatures, flow rates, and gas compositions compared to conventional diesel mode, which can be detrimental for the oxidation of THC and CO in production DOCs designed for conventional diesel operation. Platinum group metals (PGM) loadings may not be suitable for LTC modes, and there is evidence of increased inhibition of conversion reactions with high levels of THC emissions in the exhaust in LTC mode. There is a lack of systematic investigations on the light-off characteristics of oxidation catalysts for LTC engines. This work aims to develop a robust 1-D mathematical model of oxidation catalysts for conventional diesel and LTC strategies using finite difference method, collecting experimental data in an in-house engine test facility. Reactor studies with real exhaust gases will determine their light-off characteristics in LTC modes and improve the 1-D model. The developed 1-D model will enable parametric studies of oxidation catalysts for LTC engines, allowing for optimal PGM loading, Pt:Pd ratio, washcoat material, and substrate specifications. This model will be a robust tool for designing and validating oxidation catalysts for both conventional diesel and LTC engines.