Optimisation of performance parameters of stationary VCR diesel engine using hybrid FTOPSIS-FAHP approach

Abstract

ABSTRACT This paper deals with the hybrid FTOPSIS-FAHP approach to optimise the performance parameters of the stationary VCR diesel engine fuelled with jatropha biodiesel. Three performance parameters known as performance defining attributes (PDAs), i.e. brake thermal efficiency, smoke and NOx, have been used for the performance prediction. Experiments on the engine have been performed at a constant speed of 1500 rpm with variation of load (12–24 Nm), compression ratio (16.5–19.5), injection timing (19–25 CA btdc) and injection pressure (180–220 bar). In total, 16 cases are designed to obtain the results. The weight of different PDAs, BTE (0.130, 0.219, 0.351), smoke (0.097, 0.151, 0.280) and NOx (0.403, 0.630, 0.957), respectively, has been evaluated with the help of FAHP. The test number (alternative) of 08 with a load of 16 Nm, compression ratio of 19.5, injection timing of 21 CA btdc and injection pressure of 210 bar exhibit the optimal formulation. Abbreviations: BSFC: Brake specific fuel consumption; BTE: Brake thermal efficiency; CA: Crank angle; CO: Carbon monoxides; CR: Compression ratio; FAHP: Fuzzy analytical hierarchy process; : Fuzzy positive ideal solution; : Fuzzy negative ideal solution; FTOPSIS: Fuzzy technique for order preference by similarity of an ideal solution; HC: Hydrocarbons; IP: Injection pressure; IT: Injection timings; MCDM: Multi criteria decision making; PDA: Performance defining attributes; PM: Particulate matter; VCR: Variable compression ratio