Bastian Holderbaum

Fuel formulation effects on the soot morphology and diesel particulate filter regeneration in a future optimized high-efficiency combustion system

The focus of research is shifting toward development of new engine fuels for optimized combustion systems. The altered chemical structure of these new fuels may impact their thermal decomposition chemistry during the ignition process and hence the in-cylinder conditions for particulate formation and post oxidation. This work fundamentally focuses on the influence of the fuel properties on particulate matter morphology and, thereby, the regeneration behavior of diesel particulate filters. The experiments for particulate analysis were conducted with a single-cylinder diesel research engine designed for future passenger car applications. A detailed analysis of soot characteristics and its consequences on diesel particulate filter behavior were studied at part-load engine operation at EU 6 engine-out nitrogen oxide level. Next to standard EN590 diesel, a paraffinic fuel was investigated as non-oxygenated biofuel candidate. A blend of the 2-methyltetrahydrofuran and di-n-butylether was studied as tailor-made oxygenated biomass-derived fuel candidate. With all fuels, samples of state-of-the-art diesel particulate filter were loaded at the research engine. In succession, the regeneration of the filters was investigated at a laboratory gas bench. Furthermore, the primary particle size, the total number concentration, and size-based number distribution were investigated in detail by means of a transmission electron microscope, condensation particle counter, and Engine Exhaust Particle Sizer™, respectively. Furthermore, the graphitic character of the soot structure was analyzed by optical measurements such as absorption coefficient. It was found that the soot oxidation temperature was decreased by ∼10 °C and ∼65 °C with the paraffinic fuel and the blend of 2-methyltetrahydrofuran and di-n-butylether, respectively, compared to conventional diesel fuel. Overall, the results indicate that with specific tailored fuels not only the total particle mass and number could be reduced but, with altering the soot structure and composition, also the energy requirement for diesel particulate filter regeneration can be reduced.

Tailored diesel engines for electrical propulsion systems or tailored electrification for future diesel powertrains

The DI Diesel engine has gained an increasing market share in the recent 25 years and has converted from a niche application to an established, highly appreciated propulsion system in the Light-Duty vehicle segment, covering passenger car as well as light commercial applications. In vehicle classes with high market penetration this low CO2 concept offers a substantial contribution to minimize Greenhouse gas (GHG) emissions from the transportation sector.

FEV ECObrid – a 48V mild hybrid concept for passenger car Diesel engines

Powertrain electrification is a key to compliance with future exhaust emission and CO2 limits. Besides conventional 12 V systems and high-voltage hybrid architectures, 48 V mild hybridization offers significant fuel economy potential and advanced emission control without the need for an entire powertrain redesign. The 48 V power net enables high recuperation capability, improved stop-start functionalities as well as electrical boosting by an electric compressor (e-Compressor) or belt-driven starter generator (BSG).