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Homogeneous charge combustion and emissions of ethanol ignited by pilot diesel fuel were investigated on a two-cylinder diesel engine. The results show that emissions depend on loads and ethanol volume fraction. At low loads, ethanol has little effects on smoke. With the increase of ethanol, NOx decreases, but CO emissions increase. At high loads, smoke emissions reduce greatly with increasing ethanol, but NOx and total hydrocarbon (THC) emissions increase. With the increase of ethanol, ignition delays, combustion duration shortens. The maximum rates of heat release for the fuel containing 10 vol% ethanol (E10) and 30 vol% ethanol (E30) increase. Brake specific energy consumption (BSEC) of E10 and E30 is improved slightly only at full loads. Compared to smoke emissions obtained on the same engine using ethanol blended diesel fuels, the tendency of smoke reduction is similar to that of homogeneous charge combustion of ethanol at the same operating conditions. But the former is more effective in reducing smoke emissions. When the engine operated at high constant loads, smoke significantly decreases with increasing ethanol and smokeless combustion can be achieved at certain ethanol volume fraction dependent on loads. In the meantime, THC emissions gradually increase. Ignition retards, peak pressure increases first and then decreases again. Indicated mean effective pressures are close to those of diesel (E0), even higher than the latter at some cases. NOx emissions are dependent on loads and ethanol volume fraction, and even are less than those of E0 under certain conditions. The results obtained from an optical diesel engine show that ethanol also shortens combustion duration, decreases flame temperature and KL factor, which indicates that ethanol can suppress soot formation in combustion chamber.

Carbon fiber composite use in automobiles and light trucks could dramatically reduce energy use and engineout emissions. However, worldwide capacity of 28,000 tonnes per year of carbon fiber from polyacrylonitrile (PAN) and petroleum pitch could support limited automotive use. Production of high-volume, industrialgrade fiber from renewable and recycled polymers (lignin, recycled plastics, regenerated cellulosics) could meet automotive demand. Profiles of material volumes, carbon content, and melting points indicate several attractive candidates for production melt-spun carbon fiber feedstocks. Effects on the carbon fiber production cycle and its integration into automotive production are discussed.

Methyl esters obtained from the most interesting Spanish oleaginous crops for energy use -sunflower and cynara cardunculus- were both used as diesel fuels in this work, pure and in 25% blends with a reference commercial fuel which was also used pure. A stationary engine test bed, together with the appropriate instrumentation for chemical and morphological analysis, allowed to evaluate the effect of these fuels on the engine emissions, particularly in the main particulate matter characteristics, such as soluble organic fraction, origin of adsorbed hydrocarbons, sulphate content, particle number per unit filter surface, and mean particle diameter. Both the consideration of the main thermochemical properties of the tested fuels and the computations of a chemical equilibrium model were helpful for the analysis of the experimental results. These results proved that the use of these vegetable esters provides a significant reduction on particulate emissions, mainly due to reduced soot and sulphate formation. On the contrary, no increases on NOx emissions nor reductions on mean particle size were found.

Combusiton of pine pyrolysis oil droplets was studied at different pressures up to a maximum of 60 bar in a single-droplet combustion chamber. Oil droplets, with diameters between 400 \gmm and 120 \gmm were suspended to a thermocouple of to a quartz fiber. Their behavior was followed by means of high-speed digital imaging based on a shadowgraph scheme. About two thousands of frames were collected during every test with acquisition speed between 400 and 4000 frames/s. Droplets were easy to ignite at normal as well as at high pressure. Increasing the pressure the intensity of swelling phenomena, undergone by droplets, decreased and completely disappeared at pressures higher than 20 bar. However, bubbling and foaming were always observed. Liquid-phase pyrolysis and the formation of cenospheres as combustion residual were observed under all the pressure conditions.