Experimental Investigation of Gasoline Fumigation in a Turbocharged IDI Diesel Engine

Abstract

In the present study the effects of gasoline fumigation (GF) in a turbocharged indirect injection (IDI) diesel engine have been investigated experimentally. Here an elementary carburetor which main jet opening (MJO) can be adjusted by a fine threaded screw has been installed on the inlet pipe of diesel engine. Thus gasoline at low amounts can be injected in the inlet air ant it evaporates during intake and compression processes. The engine operates at diesel principles and it is thought that instantaneous burning of fumigated gasoline will enhance the combustion and performance of diesel engine. Here the experiments have been performed for 2000, 3000 and 4000 rpm, at different fuel delivery rates (FDR). FDRs have been taken as (29, 33, 50, 67 and 75) % for 2000 rpm, (42, 50, 67, 75 and 83) % for 3000 rpm and (50, 67, 75, 83 and 100) for 4000 rpm. Also, experiments have been performed at 5 and 6 different carburetor MJOs for (2000, 3000) rpm and 4000 rpm respectively. By evaluating of experimental results, it is determined that effective power generally reduces at all of the engine speeds, whereas at some instances it takes values close to the neat diesel fuel (NDF). It is observed that the decrease ratio of effective power increases especially at low fumigation ratios, but it reduces for higher gasoline ratios. On the other hand, it is determined that brake specific fuel consumption (BSFC) reduces and thus effective efficiency increases. Similarly the BSFC reduction and effective efficiency increment take higher values for high gasoline ratios. Finally it has been seen that, BSFC reduces approximately at the levels of 5%. Also NOx concentration decreases approximately at the levels of 10%. Cylinder gas pressure becomes higher than NDF at the beginning of the combustion process, it reduces through to the end of the combustion and it again takes higher values at the end of expansion and during exhaust processes. Here the effect of the GF on the smoke formation has also been investigated. It is determined that, smoke index K reduces for up to (6–8) % GF and it begins to increase after 8% gasoline ratio. Its maximum reduction ratio is 20% and it is obtained at 8% GF for 2500 rpm.