Ignition and Combustion Characteristics of Impinging Diesel and Biodiesel Blended Sprays Under Diesel Engine-Like Operating Conditions

Abstract

In present work, ignition and combustion characteristics of impinging diesel and biodiesel blended diesel sprays are examined experimentally in constant volume chamber at diesel engine-like experimental conditions. Comparative study of ignition delay (ID) and duration of combustion (DOC) for two selected fuels are done using various transducers or sensors. Commercially available diesel and biodiesel blended diesel (50% diesel and 50% biodiesel by v/v) fuels are investigated. Biodiesel produced from waste vegetable oil is chosen for blending. Operating conditions include hot surface temperature (HST) range (350–450 °C) and cylinder air pressure (CP) range (2–4 MPa) at 300 bar-fuel injection pressure (IP). It is observed that ID and DOC of each fuel reduce significantly with increase in HST and CP. It is investigated that ID and DOC of blended sprays are substantially lesser than diesel sprays at present experimental conditions. Lower magnitudes of ID and DOC of blended sprays are attributed to distinct differences in properties of selected fuels. Highest fall in ID of biodiesel blended sprays than diesel sprays is found at lower HST of 623 K for all CP. Variation of ID of both fuels is found to be nonlinear with HST. It is also deduced that differences in DOC of two selected fuels mitigate at higher HST (673 K) for all CP and at higher CP (40 bar) for all HST values. Higher biodiesel content blended fuels seem to be an attractive choice in DI diesel engines having fuel impingement.