A Compression Ignition (CI) engine was operated in dual-fuel mode with simulated biogas as primary fuel and diesel as pilot fuel. The effects of four intake parameters, viz. biogas flow rate, methane fraction of biogas, applied torque and charge temperature, on engine performance were investigated under constant speed operation. The number of experimental trials was reduced to 16 using Taguchi's approach. Higher-the-better (HTB) or lower-the-better (LTB) criteria for signal-to-noise ratio (SNR) were used to optimise five performance indices. Lower biogas flow rates and methane fractions provide better performance in general. However, increasing the biogas flow rate and methane fraction enhances diesel substitution. Analysis of variance (ANOVA) showed that engine torque was the main contributing factor for most of the performance indices. Charge temperature and biogas flow rate made significant contributions towards volumetric efficiency. Volumetric efficiency and overall equivalence ratio are also affected by the methane fraction of biogas. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.
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