Impact of Cold and Hot Exhaust Gas Recirculation on Diesel Engine
Today most of the transport vehicles in countries like India where cost effective is the predominant criteria utilize diesel engines rather than petrol engines. From past 5 years usage of diesel engines was rapid which can be addressed from the sales report of many automobile companies. The reason behind this could be cost of diesel fuel and efficiency of the diesel engine when compared to petrol engine. But when we look on the worse side of diesel engine, emissions from diesel engine are high especially NOx. So there is a need for a technique which could reduce the emissions without affecting the performance of engine. One such technique could be Exhaust gas recirculation. Present paper aims to find the impact of cold and hot EGR on emissions of diesel engine.
Thermally efficient advanced diesel exhaust aftertreatment for cleaner vehicles
Increased diesel vehicle use and growing concerns about the health and environmental effects of exhaust gas pollutants lead to a greater attention upon the reduction of vehicle emissions. The evolution of driving patterns and vehicle technologies lead to lower average exhaust gas temperatures. This can limit the diesel aftertreatment (catalyst) system's ability to meet increasingly stringent emissions legislation. A thermally efficient aftertreatment system can be produced through advanced and novel catalyst designs. The research work presented in this thesis investigates diesel oxidation catalyst (DOC) and exhaust gas properties that can enhance aftertreatment performance at low temperatures. 
Firstly, an advanced two-catalyst configuration is designed that widens the aftertreatment system operating temperature window. Catalyst cell density, wall thickness and material choices were optimised using theoretical equations, modelling tools and an experimental approach. 
Secondly, strategics were developed to assist the aftertreatment low temperature activity through the understanding of exhaust species interactions (inhibition and promotion) within the catalyst. This was achieved by varying the exhaust composition at the catalyst inlet, using alternative fuels and combustion modes. 
Finally, a catalyst component combining a filtration/oxidation function (partial-flow filter) was found to promote particulate removal while reducing the needs for diesel particulate filter active regeneration.
Effects of the addition of ethanol and cetane number improver on the combustion and emission characteristics of a compression ignition engine
Abstract Combustion and emission characteristics of a direct-injection diesel engine fuelled with diesel—ethanol blends were investigated. The results show that the ignition delay and the premixed combustion duration increase, while the diffusive combustion duration and the total combustion duration decrease with increase in the oxygen mass fraction in the blends. The addition of 0.2 per cent volume fraction of cetane number improver (isoamyl nitrite) could mean that the ignition delay and the premixed combustion duration of the fuel blends with 10vol% ethanol fraction recover to those of diesel fuel. Meanwhile, with the increase in the ethanol fraction in the fuel blends, the centre of the heat release curve moves closer to the top dead centre. The brake specific fuel consumption increases, while the diesel equivalent brake specific fuel consumption decreases with increase in the ethanol fraction. The exhaust smoke concentration increases and exhaust nitrogen oxide (NO x ) concentration decreases on prolonging the fuel delivery advance angle for both diesel fuel and the blended fuels. For a specific fuel injection advance angle, the exhaust smoke concentration shows a large decrease and the exhaust NO x concentration a small decrease on ethanol addition.