Author(s)

Ugochukwu Charles Ngwaka^1*, Chidebere Diyoke¹, Nnamdi Anosike²

¹Mechanical Engineering Department, Enugu State University of Science and Technology, Enugu, Nigeria.
²Mechanical Engineering Department, Nnamdi Azikiwe University, Awka, Nigeria.

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 NO_x formation was incorporated to predict NO_x emission. A different approach was assumed for the equilibrium temperature. An approach of using the average cycle temperature within NO_x 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 NO_x 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 NO_x formation temperature region could be useful in predicting NO_x formation with reasonable degree of accuracy. Injection timing, mass ratio of injected fuel, and dwell between pulses have significant effects on the NO_x emission and engine performance. The results also show that as the number of pulses increases, NO_x emission and engine performance decrease. For optimal balance between NO_x and engine performance, mass of the pilot injection should be between 10 and 25% of the total mass of fuel used per cycle.

Multiple Injection, Diesel Engine, Emission

Ngwaka, U. , Diyoke, C. and Anosike, N. (2016) Single Zone, Zero Dimensional Model of Diesel Multiple-Injection. Energy and Power Engineering, 8, 297-312. doi: 10.4236/epe.2016.89028.