Effect of piston geometry on combustion characteristics with and without EGR when fueled with methyl ester in VCR engine.

In the current investigation, a 3.5kw compression ignition (CI) engine was fueled with behada, chicken fat, and turmeric oil methyl ester. The purpose of the current research was to explore the parameters of combustion such as cylinder combustion pressure, rates of pressure rise, net heat release rate, mean gas temperature, combustion duration, and combustion event time (crank angle). CI engine was modified by changing the piston head (square and tangential groove top) for methyl ester diesel blend operations. In the study diesel fuel is designated as B00 and methyl ester as B20. The influence of compression ratio (CR16 and CR18) with exhaust gas re-circulation (EGR 0% and EGR 10%) on combustion parameters was studied. Tangential groove top piston with compression ratio 18:1, EGR10%, and methyl ester B20, shows significant controlled and homogeneous combustion. Notable findings revealed a maximum cylinder pressure of 80 bar occurred at 40 milliseconds (ms) after the top dead center (aTDC) and the rate of pressure increases to 5.8 bar/deg when the piston is at the top dead center (TDC). Also, considerable heat release of 60 J/deg and a maximum mean gas temperature of 1750oC was recorded. The rise in the rate of pressure results in decreased ignition delay and combustion time. In addition, this method efficiently using B20 fuel with slight engine modification resulted in homogenous and clean combustion which will be helpful to reduce pollution. [ABSTRACT FROM AUTHOR]