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A quasi-steady gas-jet model was applied to examine the spray penetration and deflection in swirling flow during the ignition-delay period in an open-chamber diesel engine timed to start combustion at top dead center. The input to the gas-jet model included measured values of ignition delay and mean fuel-injection velocity. Attempts were made to correlate measured fuel-consumption and soot-emissions data with mixing parameters based on calculated spray penetration and deflection. The engine parameters examined were piston-bowl geometry, compression ratio, speed, and overall air-fuel ratio. Four empirical correlations proposed in the literature were examined. The correlations, which were based on spray penetration and deflection in the swirl direction, represented overall degrees of fuel distribution in the combustion chamber and of utilization of the cylinder air.

The predictive capability of a phenomenological spray-combustion model was evaluated for diesel engine performance, combustion, and emissions. The data used for comparisons with the predictions resulted from tests on two single-cylinder research-type open-chamber diesel engines -- a 2.0-L per cylinder heavy-duty engine and a 0.52-L per cylinder light-duty engine. The data covered wide ranges of speed and overall air-fuel ratio. Such global performance quantities as indicated mean effective pressure and indicated thermal efficiency predicted by the model agreed with experimental results from both engines within 5%. Pressure-time and heat-release rate predictions agreed within 5-15%. However, further improvements are needed before the model can be used reliably for emissions predictions. Specifically, predictions of nitric oxide (NO) and non-volatile particulate (soot) were in poor agreement with the measurements, especially for the light-duty engine.