The effects of different types of biodiesels and biodiesel-bioethanol-diesel blends on the cyclic variations and correlation coefficient

In this study, the changes in cycle to cycle variations and correlation coefficient between main combustion parameters were revealed by usage of biodiesels produced from different raw materials and bioethanol-biodiesel-diesel ternary blends under three different engine loads and constant engine speed in a direct injection heavy duty diesel engine. The results showed that maximum cylinder gas pressure (P-max) values of the chicken fat biodiesel (CFB) and fleshing oil biodiesel (FOB) were obtained higher than that of petroleum-based diesel fuel (PBDF), while the maximum pressure rise rate (MPRR) values increased with increase in bioethanol percentage in the biodiesel-diesel blends at full load conditions. The maximum coefficient variation (COV) was obtained for MPRR when compared with P-max and indicated mean effective pressure (IMEP). The values of the COVPmax and the COVMPRR increased with an increase in bioethanol content in ternary blends. The correlation coefficient (R) between IMEP and P-max was higher than those of R(IMEP, MPRR) and R(MPRR, P-max). It showed that the fuel properties had much more dominant effect on the coefficient variation and correlation coefficient in comparison with engine load.