The purpose of this work was to investigate the impact of marine gas oil (MGO)/biodiesel blends on the exhaust emissions and fuel consumption in a single cylinder, stationary, diesel engine. Three different origins of biodiesel were used as the blending feedstock with the reference MGO, at proportions of 5 and 10% by volume. Methyl esters were examined according to the automotive FAME standard EN 14214. The baseline MGO and biodiesel blends were examined according to ISO 8217:2005 specifications for the DMA category. Independently of the biodiesel used, a decrease of PM, HC, CO and CO(2) emissions was observed. Emissions of NO(x) were also lower with respect to MGO. This reduction in NO(x) may be attributed to some physicochemical properties of the fuels applied, such as the higher cetane number and the lower volatility of methyl esters. Reductions in PM for biodiesel blends were lower in the exhaust than those of the reference fuel which was attributed to the oxygen content and the near absence of sulphur and aromatics compounds in biodiesel. However, a slight increase in fuel consumption was observed for the biodiesel blends that may be tolerated due to the exhaust emissions benefits. Brake thermal efficiency was also determined. Unregulated emissions were characterized by determining the soluble organic fraction content of the particulate matter.

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This work involves the development of 'real-world' driving cycles using on-road data from the greater area of Athens, Greece. Two different methodologies of driving-cycle development are presented here, based on the MATLAB code. Driving patterns from various test vehicles were processed to form driving cycles consisting of a specific number of driving periods. The main criterion for the design and acceptance of each method was the correlation of the resulting driving cycles with the corresponding characteristics of the processed road data. Time is an important issue when processing data. Applying the same set of data to both methods, method A needed 5 h to complete the processing compared with 9 s for method B. The corresponding average accuracies were 99.9% and 97.2% respectively. The road gradient was taken into account for the development of the driving cycles. For method A, the road gradient was included in the final result by intervening in the mean positive accelerations and the mean negative accelerations. Those were increased by 11.99% and 16.06% respectively for the Greek Urban Driving Cycle for Motorcycles. For method B, the road gradient was assimilated by a 'load cycle' expressed in kilowatts and used in combination with the developed driving cycle, thus forming a complete chassis dynamometer test. The load cycle was produced by calculating the power related to the vehicle's mass that holds or assists it when driving uphill or downhill. The Greek Urban Driving Cycle for Motorcycles was developed using method A. Its characteristics include the follwoing: a duration of 822 s, an average speed of 28.86 km/h, a stop-time percentage of 12.04 and a positive acceleration of 0.6065 m/s 2 . Method B was used for the Greek Urban Driving Cycle for passenger cars. Some of its characteristics include the following: a duration of 1175 s, an average speed of 18.67 km/h, a stop-time percentage of 31.66 and a positive acceleration of 0.692 m/s 2 .