Abstract
This study examines the combustion properties of pine oil (PO), which is classified as a low viscosity, low cetane (LVLC) fuel. It highlights the superior performance of pine oil in comparison to diesel fuel, but acknowledges that its low cetane index causes a delay in combustion initiation, which consequently results in elevated NOx emissions. Fuel atomization, evaporation, and air/fuel mixing is enhanced by the reduced viscosity and boiling point of PO in comparison to diesel. Nevertheless, the low cetane index of PO restricts its applicability as a diesel fuel substitute in CI engines. Because of the significant heat release that occurs subsequent to an extended ignition delay, NOx emissions tend to rise with less viscous and low cetane (LVLC) fuels. A range of cetane improvers, such as diethyl ether (DEE), benzyl alcohol (Bn), diglyme (DGE), and methyl tert-butyl ether (MTBE), have demonstrated effectiveness in mitigating nitrogen oxide (NOx) emissions upon introduction into pine oil. All the cetane improvers were added 5 % and 10 % by volume with pine oil.
A twin-cylinder tractor engine operating at a constant speed of 1500 revolutions per minute was utilized in this testing. In order to achieve a warm-up condition that would enable the smooth operation of PO, the engine was initially operated on diesel fuel. At maximum load condition, NOx emission of PO was higher by 8% in comparison to diesel. NOx emission was significantly reduced with addition of cetane improvers. Maximum reduction of 7% was observed with PO + MTBE 10% in comparison to PO which is in par with diesel. An increase in HC and CO emission was observed with all cetane improver addition with PO.