Year: 2017 Volume: 1 Issue: 4 Page: 151-163
A COMPUTATIONAL AND EXPERIMENTAL INVESTIGATION OF THE EFFECTS OF SECOND INJECTION TIMING ON A DI-HCCI ENGINE FUELED WITH GASOLINE-ETHANOL BLENDS
MUSTAFA DENİZ ALTINKURT, ALİ TÜRKCAN
In this study, experimental and computational investigation of a homogeneous charge compression ignition (HCCI) combustion engine were carried out using gasoline-ethanol blends and two stage direct injection (TSDI) strategy. First injection was fixed in intake stroke while second injection was varied close to the compression top dead center (TDC). For this reason, a diesel engine was modified to work as an electronically controlled DI-HCCI engine. The test fuels were prepared as pure gasoline and two different gasoline–ethanol blends with 10% (E10) and 20% (E20) of ethanol by mass. CFD simulations were performed using AVL’s Fire code and CFD results were compared against the experimental results of the DI-HCCI engine. The effects of various second injection timings on HCCI combustion were investigated at constant engine speed and same energy input conditions for high equivalence ratio conditions. Combustion temperature and NOx emissions were investigated visually using CFD model results. Both experimental and CFD studies showed that retarding second fuel injection timing reduces the peak in-cylinder pressure and rate of heat release. Combustion phases and NOx emissions were able to be controlled by changing second injection timing.
Anahtar Kelimeler (Keywords): DI-HCCI, Second injection, CFD simulation, Ethanol, Gasoline