Using low viscosity micro-emulsification fuels composed of waste frying oil-diesel fuel-higher bio-alcohols in a turbocharged-CRDI diesel engine

Abstract

In this experimental study, low viscosity (<5 mm2.s−1) ternary micro-emulsification fuels contain 50% petro-diesel, 30% waste frying oil and 20% n-butanol or iso-propanol. To observe the effects of ternary fuels on the characteristics of a turbocharged, common rail direct injection diesel engine, the engine tests were performed at the fixed engine speed of 2000 rpm and five different engine loads (BMEP: 3.3–10.0 bar). The results show that brake specific fuel consumption increased about 18% while thermal efficiency decreased about 7% when using ternary fuel. Although the start and end of injection timings of all test fuels were very close to each other at the low engine loads, both pilot and main injection timings of ternary fuels were relatively earlier compared to petro-diesel. Injection amount and rates were higher for ternary fuels at all engine loads. Up to 6.6 bar of engine load, the maximum cylinder gas pressures (Pmax) of petro-diesel were higher, but those of ternary micro-emulsification fuels were higher at the engine loads of 8.3 bar and 10.0 bar. Particularly at high engine loads, combustion of petro-diesel started and ended at comparatively later crank angles, so combustion durations were longer than those of ternary fuels. The results show that petro-diesel fuel provided better CO, THC and NOx emissions, whereas CO2 emissions of test fuels were close to each other. When the higher bio-alcohols were compared to each other, it was seen that the ternary fuel with iso-propanol had better results than the ternary fuel with n-butanol.