Final Euro6d emission legislation with the new homologation cycle and Real Driving Emission requirements has set a strong challenge for the ICE Passenger Car applications.
Thanks to their well-known low fuel consumption characteristics, Diesel Engines can play a key role for the fulfillment of the European 2020 CO2 fleet target but need to confirm their capability to fully control noxious emissions even in extreme operating conditions, while restraining the overall engine costs and complexity.
CO2 and NOx emissions reduction are considered the main drivers for diesel engine evolution. In this perspective, Exhaust Gas After-treatment and Combustion System have been identified as the two main technology aspects to be developed.
The purpose of this paper is to describe the evolution paths of these two technologies and the results achieved so far in terms of noxious emissions reduction.
A methodology has been developed to predict Diesel combustion evolution and its main characteristics. Various combustion chambers and fuel injection systems have been analyzed through simulations, selecting the most promising ones to be tested on the engine test bench.
Having the NSC (NOx Storage Catalyst) + DPF (Diesel Particulate Filter) as reference, a new after-treatment system has been defined integrating active SCR (Selective Catalytic Reduction) and DPF in a single component (SCRF - SCR on Filter), installed in close-coupled position.
The right combination of an Advanced Combustion system with a highly efficient SCRF After-treatment system, clearly indicated the potential for the diesel engine to reduce fuel consumption while keeping a very low NOx emissions level.
The activity described in this paper has been co-funded by the European REWARD project.