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Different intake valve timings and fuel injection amounts were tested in order to identify their effects on exhaust emissions and combustion characteristics using variable valve actuation (VVA) in a Homogeneous Charge Compression Ignition (HCCI) engine. The HCCI engine is a promising concept for future automobile engines and stationary power plants. The two-stage ignition process in a HCCI engine creates advanced ignition and stratified combustion, which makes the ignition timing and combustion rate controllable. Meanwhile, the periphery of the fuel-rich zone leads to fierce burning, which results in slightly high NOx emissions. The experiments were conducted in a modified single cylinder water-cooled diesel engine. In this experiment we use diesel, bio-diesel (Jatropha) and gasoline as the fuel at different mixing ratios. HCCI has advantages in high thermal efficiency and low emissions and could possibly become a promising combustion method in internal combustion engines.

In this work, biodiesel obtained from the transesterfication of Jatropha seeds and Fish wastes is used as an alternative fuel to diesel in stationary single cylinder diesel engines. The biodiesel obtained has good ignition ability due to its relatively high cetane number compared to that of conventional diesel fuel. The performance, combustion and emission tests using Jatropha Oil Methyl Ester (JOME), Fish Oil Methyl Ester (FOME) and their blends (20% JOME and 20% FOME) with diesel were carried out at constant speed and variable loads condition. The results showed that both blends could be used as fuels for diesel engine without any major modification on the engine. Carbon monoxide (CO), UBHC and smoke emissions were observed to be lesser at all loads for both the blends compared to diesel fuel, while NOx emission was slightly higher. JOME blend was found to be better than FOME blend.

The use of oxygenated fuels seems to be a promising solution for reducing particulate emissions in existing and future diesel motor vehicles. In this work, the influence of the addition of oxygenated hydrocarbons to diesel fuels on performance and emission parameters of a diesel engine is experimentally studied. 3-Pentanone (C 5 H 10 O) and Methyl anon (C 7 H 12 O) were used as oxygenated fuel additives. It was found that the addition of oxygenated hydrocarbons reduced the production of soot precursors with respect to the availability of oxygen content in the fuel. On the other hand, a serious increase of NOx emissions is observed. For this reason the use of exhaust gas recirculation (EGR) to control NOx emissions is examined. From the analysis of it is examined experimental findings, it is seen that the use of EGR causes a sharp reduction in NOx and smoke simultaneously. On the other hand, EGR results in a slight reduction of engine efficiency and maximum combustion pressure which in any case does not alter the benefits obtained from the oxygenated fuel.

To meet the strict emissions regulations, it is required to test and identify highly active and durable catalysts. This paper analyzes the potential of catalytic system in a diesel engine using aluminium-phosphate supported copper phosphate catalytic converter to control nitrous oxide and particulate matter. The particulate matter is reduced by Catalyzed Diesel Particulate Filter (CDPF) and Diesel Oxidation Catalysts (DOC) systems. The soluble organic fractions of diesel particulate are oxidized by DOC system of the newly developed catalyst coated wire meshes, and the un-soluble fractions of particulate matter are filtered by the same wire mesh filter materials. The experimental results from this investigation demonstrate that 40.58% of NOx reduction is achievable, which clearly shows the possibilities of replacing the noble metal catalysts