PARAMETRIC STUDIES ON A COAL-FUELED DIESEL-ENGINE

The ignition and combustion processes of coal-water slurry (CWS) in a prechamber type diesel engine were investigated in this work. Specific engine and fuel parameters studied included: (i) needle lift pressure; (ii) inlet air temperature; (iii) fuel injection timing; and (iv) percent coal loading in the slurry fuel. Analysis of the experimental data utilized a numerical simulation of the combustion process using submodels for the key physical and chemical processes. Energy release schedules were determined using a one-zone thermodynamic analysis with measured cylinder pressure as a function of time. Successful operation of the engine using the coal slurry required modifications to the engine and support systems. These modifications are briefly discussed in this paper. The major conclusions of the work include: (i) higher needle lift pressures led to shorter ignition delay times for the CWS fuel; (ii) increasing the inlet air temperature shortened ignition delay times and improved burning rates of the slurry; and (iii) dilution of the slurry with water can significantly affect the combustion processes of the fuel.