Impact of injector deposits and spark plug gap on engine performance and emissions

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Badawy, Tawfik (2018). Impact of injector deposits and spark plug gap on engine performance and emissions. University of Birmingham. Ph.D.

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Abstract

This research has focused on obtaining a comprehensive understanding of gasoline direct injector coking effects on fuel injection, engine performance and emissions. The impact of spark plug electrode gap on flame kernel development, engine performance, and emissions was also investigated. In this study, the deposit build-up inside the injector nozzles and on the injector tips reduced the plume cone angle, while it increased the plume penetration length, plume separation angles, mean droplet velocity and size for the coked injector. The coked injectors showed a higher degree of inhomogeneity and poorer repeatability in mixture preparation. The combustion analysis demonstrated that the coked injectors showed lower load and lower combustion stability, compared with the clean injector under the same operating conditions. The increase of the spark plug gap resulted in an increase for the flame kernel growth area. The maximum in-cylinder pressure, turbulent flame speed, heat release rate and the mass fraction burned increased with the spark plug gap. The engine output increased slightly and the combustion process became more stable due to the reduction in cyclic variations as the spark plug gap increased. With the maximum spark plug gap, the engine produced minimum hydrocarbon emissions and particulate number concentration.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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