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The ASTM D6890 method predicts cetane numbers of diesel fuels based on the measured ignition delay in a combustion bomb (Ignition Quality Tester™). The device is calibrated using n-heptane as the reference fuel. When n-heptane was tested in the IQT™ device over a range of temperatures and pressures, the measured ignition delay did not correlate with the chemical autoignition delay normally associated with a stoichiometric, homogeneous mixture as predicted by detailed chemical kinetic models. This paper describes an investigation to study and reconcile this discrepancy, using (CFD) techniques to explore the physical conditions prevailing in the IQT™ device. Significant insights regarding the flow patterns, thermal gradients and air/fuel ratio profiles were obtained from the analysis. The calculation yielded ignition-delay predictions (defined by the first appearance of a local autoignition) that correlated well with IQT™ experimental data.

Pouch cells are increasingly popular form factors for the construction of energy storage systems in electric vehicles of all classes. Knowledge of the stress generated by these higher capacity pouch cells is critical to properly design battery modules and packs for both normal and abnormal operation. Existing literature predominantly offers data on smaller pouch cells with capacities of less than 10 Ah, leaving a gap in our understanding of the behavior of these larger cells. This experimental study aimed to bridge this knowledge gap by measuring loads and stresses in constrained 65 Ah pouch cells under both cycling and abuse conditions. To capture the desired responses, a load cell was located within a robust fixture to measure cell stress in real time after the application of a preload of approximately 30 kilograms or 294 N, equivalent to a pressure of 0.063 bar, with a fixed displacement.

The paper presents a statistical analysis of burn rates observed in a single cylinder spark-ignition engine. Parameters in a functional description of the burn rate were correlated to fuel blend composition and engine parameters. The analysis indicated that burn rate parameters were inter-linked and did not change in isolation. The use of sound statistical experimental design and analysis proved worthwhile in revealing tendencies that may otherwise have been misinterpreted. The features of the burn rate were discussed in lieu of the engine design, blend properties and test conditions.

A recently approved method for cetane determination using the Ignition -Quality Tester (IQT™) is based on an ignition delay measurement in a combustion bomb apparatus, which is empirically correlated to cetane number. The correlation assumes that all fuels will respond to the different pressure and temperature domains of the IQT™ and the cetane test engine in the same way. This assumption was investigated at a more fundamental level by conducting IQT™ measurements at different pressure and temperature points and characterising the ignition delay of the fuel in terms of an Arrhenius autoignition model. The fuel model was combined with a mathematical model of the cetane engine and the concept was evaluated using a variety of test fuels, including the diesel cetane rating reference fuels. The analysis technique was able to accurately predict the cetane number in all cases.