Experimental Investigation On Cylinder Vibration Analysis, Combustion, Emission and Performance Of An IDI Engine

1. Introduction

Biodiesel is as an attractive alternative fuel for replacement of conventional diesel with small or no changes made to the original design of the engine. 100% replacement entails some problems such as excess Nitrogen oxide (NO_x) generation in the exhaust gases and crankcase oil dilution. Biodiesel made from non-edible oils is a safer choice. Mahua biodiesel (MME) is one of the many fuels receiving attention as an alternative fuel for diesel engines, and carries religious significance for being used in temples. Much work and research have been carried out on a Direct Injection (DI) diesel engine with biodiesel and additives. Research in biodiesel acknowledges its advantages and it is envisaged that the emissions can be substantially reduced. Biodiesel is an oxygenated fuel containing approximately 11% of O₂ in its molecular structure. This may lead to the release of more NO_x in the exhaust gas (Murugesan et al., 2009, Basha et al., 2009, Wu et al., 2009 and Sukumar Puhan et al., 2005). In this study, an effort has been made to reduce crank case oil dilution and NO_x emission by adopting an Indirect Diesel Injection (IDI) engine.

IDI engines are suitable for the combustion of lower graded fuels and create the air entrainment in the swirl chamber and in the main chamber. The injection pressure employed is lower than that of DI engine and the compression ratio is higher (Turkcan and Canakci, 2011). Higher cetane fuels like biodiesel will create higher swirl in the pre combustion chamber leading to better combustion in the main chamber. Diesel fuel produces higher emissions and hence biodiesel is recommended in lieu of diesel fuel. Biodiesel increases NO_x in tail pipe emission, which prompted to use methanol additive to create low temperature combustion. The additive Methanol’s boiling point is 64.7⁰C, latent heat of evaporation is 1.11 MJ/kg, cetane number is 4 and auto ignition temperature is 470⁰C (Rao and Rao, 2014). Hence methanol encourages low temperature combustion in the combustion process. However, it is necessary to investigate the Performance, emission and combustion propensity in the wake of knock and detonation in fuel burning. This aspect finally led to study on heat release rate and engine cylinder vibration analysis with alternate fuels.