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The present work relates to the investigation of the basic oxidation characteristics of iron and aluminium nanoparticles as well as the feasibility of their combustion under both Internal Combustion Engine (ICE)-like and real engine conditions. Based on a series of proof-of-concept experiments, combustion was found to be feasible taking place in a controllable way and bearing similarities to the respective case of conventional fuels. These studies were complimented by relevant in-situ and ex-situ/post-analysis, in order to elaborate the fundamental phenomena occurring during combustion as well as the extent and ‘quality’ of the process. The oxidation mechanisms of the two metallic fuels appear different and -as expected- the energy release during combustion of aluminium is significantly higher than that released in the case of iron.

The EU emission standards for new rail Diesel engines are becoming even more stringent. EGR and SCR technologies can both be used to reduce NOx emissions; however, the use of EGR is usually accompanied by an increase in PM emissions and may require a DPF. On the other hand, the use of SCR requires on-board storage of urea. Thus, it is necessary to study these trade-offs in order to understand how these technologies can best be used in rail applications to meet new emission standards. The present study assesses the application of these technologies in Diesel railcars on a quantitative basis using one and three dimensional numerical simulation tools. In particular, the study considers a 560 kW railcar engine with the use of either EGR or SCR based solutions for NOx reduction. The NOx and PM emissions performances are evaluated over the C1 homologation cycle.

Exhaust Gas Recirculation (EGR) is an effective method to reduce Nitrogen Oxide emissions. In recent years the trend of increasing EGR rate in-cylinders is an integral part of most improvements in combustion technology developments. The object of this work is to study the influence of EGR rate on the physical and chemical properties of soot particles. Soot from several operating points of a diesel engine run were collected on a high temperature filters. The pressure drop behavior during the soot loading was monitored then the soot permeability was calculated. Afterwards, the soot primary size was calculated from the obtained data and it showed good correspondence to the actual measurement. It is confirmed that all the soot primary sizes were around 22 nm in diameter. In contrast, the soot aggregate sizes and the soot concentrations were found to increase with increasing EGR rate. Subsequently, Oxidation tests were conducted to evaluate the reactivity of the soot.