TITLE:
Single Zone, Zero Dimensional Model of Diesel Multiple-Injection
AUTHORS:
Ugochukwu Charles Ngwaka, Chidebere Diyoke, Nnamdi Anosike
KEYWORDS:
Multiple Injection, Diesel Engine, Emission
JOURNAL NAME:
Energy and Power Engineering,
Vol.8 No.9,
September
6,
2016
ABSTRACT: A detailed single zone, zero dimensional model of diesel multiple-injection system was developed from first principle, for compression, combustion and expansion processes for direct injection diesel engine. Equilibrium equation of Extended Zeldolvich Mechanism (EZM) for NOx formation was incorporated to predict NOx emission. A different approach was assumed for the equilibrium temperature. An approach of using the average cycle temperature within NOx formation region was used in the EZM equilibrium equation. The model codes were implemented in MATLAB. This model is developed to investigate the effects of both single and multiple-pulse fuel injection strategies on engine performance and NOx emissions. The results obtained from the model were validated with experimental data available in the literature. Results obtained showed that the use of average cycle temperature within the NOx formation temperature region could be useful in predicting NOx formation with reasonable degree of accuracy. Injection timing, mass ratio of injected fuel, and dwell between pulses have significant effects on the NOx emission and engine performance. The results also show that as the number of pulses increases, NOx emission and engine performance decrease. For optimal balance between NOx and engine performance, mass of the pilot injection should be between 10 and 25% of the total mass of fuel used per cycle.