Particulate Matter and NOx Exhaust Aftertreatment Systems

Fleet fuel consumption is greatly reduced through the introduction of the HSDI Diesel engine. The reduced fuel consumption is then reflected in a reduction of CO2 emissions. The drop in fuel consumption and CO2 emissions results in a rise in market acceptance, which is also the result of desirable driving performance and greatly improved NVH behavior. The continuously increasing demands on placed on emissions performance also needs to be addressed. Particulate emissions can be reduced by more than 95% through the use of a diesel particulate trap. However, based on current knowledge, a further, substantial NOx engine out emission reduction for the diesel engine counteracts one of the other goals, which is reduced fuel consumption. Diesel engine compliance with current and future emission standards will require DeNOx technologies. Currently, the NH3-SCR and Lean NOx-Trap (LNT) technologies show the most promise as solutions to achieve the strict NOx standards. While the NH3-SCR technology addresses fuel consumption, the application of an additional reduction component is considered a drawback. Combining DeNOx technologies with the application DOC/DPF requires a detailed and thorough analysis of exhaust system layout at the very beginning of the engine development cycle. Modeling and simulation of emission and fuel consumption are required to determine the appropriate level of technology needed for various applications. The following information highlights the simulation results for aftertreatment components such as DOC, DPF, SCR and LNT and how various exhaust system layouts impact emission reduction.