Performance Evaluation of Di Diesel Engine using Neat Pre-heated Mahua Methyl Ester

摘要

The problem of high viscosity of vegetable oils has been approached in several ways, such as, esterification, pre-heating, mineralization and blending or dilution with diesel fuel. In this work, the non-edible oil, like Mahua (Madhuka indica) is esterified and its viscosity is brought down to 6 cSt. Nevertheless, the viscosity of Mahua Methyl Ester (MME) remains high compared to the viscosity of diesel fuel (3.1 cSt) at room temperature of 30°C. To eliminate the fuel injection problems and encourage atomisation, the MME is heated to 55°C to meet the viscosity of diesel fuel. Neat MME (B100) and neat pre-heated MME (MME 55) are tested in a laboratory based DI diesel engine replacing the conventional diesel fuel. The engine is tested with MME and MME 55 to verify the change in performance, the exhaust emission aspects and engine vibration at the selected loads (0, 1/4, 1/2,3/4, and full) and the results are compared with the base line diesel fuel to verify the feasibility of replacement. Pressure crank angle history envisages reduction in ignition delay in the case of diesel fuel and the esters. Pre-heating of the ester did not change the delay any further. Thermal efficiency and specific fuel consumption recovered after pre-heating when originally there is 5% reduction in the absolute value at full load between the diesel and the neat unheated Mahua methyl ester. 2.3% absolute value recovery is observed after pre-heating. SFC reduced by 0.04% in absolute value after pre-heating at full load which is maximum and varied betterment is observed at all loads. There is remarkable reduction in the hydrocarbon emission in the exhaust gas with the implementation of unheated methyl ester and pre-heating further decreased this emission. CO emission is higher after ester usage and pre-heating reduced CO levels at all loads. CO2 levels have increased with the application of biodiesel and pre-heating reduced this emission marginally at higher loads. NO and smoke decreased and pre-heating marginally decreased these emissions further at all loads. There is no abnormal amplitude rise at higher frequencies (between 3000 Hz to 25000 Hz) and hence indicating absence of knocking of the engine with the usage of biodiesel and pre-heated biodiesel. There is better cumulative heat release with the application of biodiesel and pre-heating does not bring about any significant change in this parameter. Keywords : Esterification; Pre-heating; Viscosity; Knocking