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Partly competing objectives, as low fuel consumption, low friction, long oil maintenance rate, and at the same time lowest exhaust emissions have to be fulfilled. Diminishing resources, continuously reduced development periods, and shortened product cycles yield detailed knowledge about oil consumption mechanisms in combustion engines to be essential. There are different ways for the lubricating oil to enter the combustion chamber: for example as blow-by gas, leakage past valve stem seals, piston rings (reverse blow-by) and evaporation from the cylinder liner wall and the combustion chamber. For a further reduction of oil consumption the investigation of these mechanisms has become more and more important. In this paper the influence of the mixture formation and the resulting fuel content in the cylinder liner wall film on the lubricant oil emission was examined.

The finite nature and instability of fossil fuel supply has led to an increasing and enduring investigation demand of alternative and regenerative fuels. The Institute for Combustion Engines at the RWTH Aachen University carried out an investigation program to explore the potential of tailor made fuels to reduce engine-out emissions while maintaining engine efficiency and an acceptable noise level. To enable optimum engine performance a range of different hydrocarbons having different fuel properties like cetane number, boiling temperature and different molecular compositions have been investigated. Paraffines and naphthenes were selected in order to better understand the effects of molecular composition and chain length on emissions and performance of an engine that was already optimized for advanced combustion performance. The diesel single-cylinder research engine used in this study will be used to meet Euro 6 emissions limits and beyond.

The operation of NOx Adsorber catalysts (NAC), also often referred to as Lean NOx Trap catalysts or NOx Storage-reduction catalysts, entails frequent periodic NOx regeneration events. These are accomplished by creating a net reducing, fuel-rich environment in the exhaust. The reduction of hydrocarbon emissions which occur during such fuel-rich events is challenging, due to the oxygen-deficient environment. In order to overcome this limitation, two possibilities exist: (i) oxygen can be stored during lean phase, to be used for hydrocarbon slip oxidation in the subsequent rich phase, or (ii) unreacted hydrocarbons can be trapped during the rich phase and oxidized during the following lean phase. In this work, two groups of catalytic solutions were developed and evaluated for hydrocarbon emission control based on these approaches: an Oxygen Storage Compound (OSC) based catalyst and zeolite-based hydrocarbon trap catalyst.

Exhaust Gas Fuel Reforming has potential to be used for on-board generation of hydrogen rich gas, reformate, and to act as an energy recovery system allowing the capture of waste exhaust heat. High exhaust gas temperature drives endothermic reforming reactions that convert hydrocarbon fuel into gaseous fuel when combined with exhaust gas over a catalyst - the result is an increase in overall fuel energy that is proportional to waste energy capture. The paper demonstrates how the combustion of reformate in a direct injection gasoline (GDI) engine via Reformed Exhaust Gas Recirculation (REGR) can be beneficial to engine performance and emissions. Bottled reformate was inducted into a single cylinder GDI engine at a range of engine loads to compare REGR to conventional EGR. The reformate composition was selected to approximate reformate produced by exhaust gas fuel reforming at typical gasoline engine exhaust temperatures.

Future heavy-duty diesel (HDD) engines are designed to have higher engine out NOx, for improved fuel economy, while reduction of the emission control technology footprint is also desired. Consequently, higher NOx reduction across compact emission control systems is required. Selective catalytic reduction (SCR) catalyst coating combined with a wall flow particulate filter (SCRF®1) is a technology that enables abatement of NOx emissions in addition to oxidation of soot from diesel engine exhausts. Vanadia based-SCR is well known for NOx reduction and is active for hydrocarbon (HC) and particulate matter (PM) oxidation. This dual functionality (oxidation and reduction reactions) of the V.SCR catalysts plus the filtration achieved by the filter substrate can help certain diesel engine applications achieve the legislative limits with a reduced packaging volume.