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One of the first alternative fuels have been fossil crude oil based containing a small amount of biomass derived compounds (bioethanol or biodiesel). Biofuels usually contain oxygenated hydrocarbons such as alcohols or esters. The increasing use of alternative fuels will occur at the same time when various after-treatment systems (oxidation catalysts, filters, SCR catalysts) will be commercialized world-widely between 2010 and 2020. The effects of biofuels on emissions and emission catalysts were reviewed widely in this study. The change in raw emissions has effects on the selection, performance and durability of catalytic systems. Bioethanol has been used widely with emission catalysts since 1990's in Brazil. The results with three-way catalysts (TWC) were analyzed in those conditions. PtRh catalysts showed the better performance and durability than Pd containing TWCs.

Stricter emission limitations for NOx and particulates in mobile applications will require the use of active aftertreatment methods like Diesel Particulate Filters (DPF), Selective Catalytic Reduction (SCR) with urea and Lean NOx Trap (LNT) as combinations in the 2010's. Due to the significant total space and required investments, a lot of efforts have been focused recently on the optimization of the combinatory aftertreatment systems (ATS). In this study the possibilities to intensify the catalytic ATS were analyzed and reviewed by the examples and studies with engines, laboratory reactors and simulations. The focus was on diesel applications, where the number of needed ATS units is the widest. The diesel engine modifications on SCR or EGR engines have to be also designed together with ATS. The intensification includes the principles of down-sizing and the integration of ATS units with control systems.

The use of biofuels in internal combustion engines changes the composition of the engine exhaust gas. When burning a biofuel blend, significant amounts of oxygenated hydrocarbons such as alcohols, ethers and aldehydes are present in the exhaust gas. It is known, that these compounds influence catalytic processes in exhaust gas converters. In this work we propose a global kinetic model for ethanol and acetaldehyde oxidation on commonly used Pt, PtPd and Pd-based catalytic oxidation converters of automobile exhaust gases. The mechanism is based on two steps: (i) partial oxidation of ethanol to acetaldehyde, and (ii) complete oxidation of acetaldehyde to CO₂ and H₂O. Kinetic parameters of ethanol and acetaldehyde reactions are evaluated on the basis of laboratory light-off experiments with several catalytic monolith samples (noble metal loading 9-140 g/cft; Pt, Pd, and PtPd; at space velocity 30 000-240 000 h-₁).