An investigation of the effects of biodiesel on combustion in a thermal barrier coated diesel engine

In this study, biodiesel fuels produced from sunflower oil methyl ester in accordance with TS EN 14214 standards was investigated as an alternative fuel source for thermal barrier coated diesel engines. For this purpose, the surfaces of the piston, cylinder head, and valve parts of the combustion chambers for a single cylinder diesel engine were coated at 250 µm thick ceramic composite Al2O3-ZrO2 (20-80%) main coating material and 100 µm NiCrAl interlayer material. The biodiesel fuel is produced from refined sunflower oil by the transesterification method. The sunflower oil methyl ester was mixed with standard diesel fuel in volumes ratio of 0%, 6%, 12% and 25% to obtain B0, B6, B12 and B25 fuel mixtures, respectively.B6, B12, B25 biodiesel fuels and B0 fuel were investigated the effects on combustion characteristics in a single cylinder standard (STD) and thermal barrier coated (TBC) of diesel engine under full load and 1400, 1800, 2200, 2600 and 3000 rpm engine speeds. Febris combustion analysis software based LabVIEWwas used to obtain data on cylinder pressure, heat release rate, rate of pressure increase, cumulative and heat release. Maximum cylinder pressure was obtained 83.65 bar in TBC engine with KB12 fuel at 1400 rpm and at 4° after top dead center (TDC). Depending on the increasing temperature with the use of test fuels in the engine with TBC, it was determined that the maximum in-cylinder gas pressure values increased compared to the maximum in-cylinder pressure values obtained from the STD engine. Maximum in-cylinder gas pressure values obtained in both TBC and STD engine occured after TDC.Maximum heat release rate was obtained 45.53 J/°CA in STD engine with B0 fuel at 1400 rpm and at 6° before TDC. Also B0, B6 and B12 fuel blends were tested on a diesel engine with thermal barrier-coated surfaces for 50 h under the same conditions. When the Scanning Electron Microscope(SEM)images and the EDS analysis results of the pistons covered with the ceramic composite main coating material are examined, it has been seen that the coating material permeates the surfaces in a very homogeneous manner and allows to work with high performance without causing any deterioration on the surfaces during working.