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Presented is a comprehensive evaluation of thermodynamic techniques used for the determination of top dead centre (TDC) in an internal combustion engine (ICE). This work thoroughly explores the assumptions made in thermodynamic calibration and assesses the impact these have through a rigorous sensitivity analysis, not previously attempted in any other study. The results of this work are presented as kernel density estimates (KDEs), an estimate of the probability density function (pdf), in order to offer both qualitative and quantitative assessments of the loss angle and the influence of the assumptions underpinning the loss angles determination. Thermodynamic loss angles ranging between -0.5°CA and -0.6°CA have been found for the engine under investigation.

This experimental study examines the effect on performance and emission outputs of a compression ignition engine operating on biodiesels of varying carbon chain length and the degree of unsaturation. A well-instrumented, heavy-duty, multi-cylinder, common-rail, turbo-charged diesel engine was used to ensure that the results contribute in a realistic way to the ongoing debate about the impact of biofuels. Comparative measurements are reported for engine performance as well as the emissions of NOx, particle number and size distribution, and the concentration of the reactive oxygen species (which provide a measure of the toxicity of emitted particles). It is shown that the biodiesels used in this study produce lower mean effective pressure, somewhat proportionally with their lower calorific values; however, the molecular structure has been shown to have little impact on the performance of the engine.