A Simulation Model to Predict the Performance of Ethanol- Gasoline Blend (E15) in a Spark Ignition Engine

Abstract

Usage of biofuels like bio-ethanol as a fuel in IC Engines is becoming prominent day by day due to their positive characteristics like biodegradability, nonpolluting, renewability, homegrown etc. Conducting experiments on real engine to establish the suitability of biofuels to IC Engines is very time consuming and expensive. Computer based simulation helps in addressing these problems. In this work an attempt is made to simulate performance and emission of SI engine using a computer program developAed with C++. For this simulation SI Engine fueled with gasoline-ethanol blend (E15) was used.     The performance parameters such as brake power, brake torque, thermal efficiency, break mean effective pressure, combustion efficiency, brake specific fuel consumption and emissions were analyzed. From the analysis, it was found that the brake power and torque for E15 is increased by 1.6% compared to E0. The fuel consumption decreased by 2.4%, 4.35% and 3.15% at lower speed, maximum power and maximum speed respectively for E15 compared to E0. This program is versatile and can be used for all types of engines and any type of blend proportion. Result indicated that the output parameters are all higher for E15 compared with E0. The molar fraction discharge of CO₂, CO and water vapor is less for E15 than E0 but molar fraction of N₂ is higher for E15 than E0. Experiments were conducted on real engine and C++ program was validated using experimental data. In experimental investigation the brake power and brake torque for E15 was increased by 2.96% and 1.6% respectively. The fuel consumption for E15 is lower by 1.3% than E0 at lower speed of 2308rpm, higher for E15 by 1.7% than E0 at highest brake power (2950rpm) and higher for E15 by 2.5% than E0 at highest speed (3440rpm).  The deviation between results obtained from simulation and experimental investigation was less than 5% for all analyzed engine parameters.

Keywords: Alternative fuels, Ethanol gasoline blends, thermodynamic analysis, C⁺⁺, SI engine