THE USE OF JET FUEL IN A DIESEL ENGINE

Abstract

The article presents a comparative analysis of the bench test results of a four-stroke, four-cylinder, direct-injection diesel engine operating on the normal 95vol% (class C) diesel fuel + 5vol% RME (DF), F-34 jet fuel (JF) and F-34 jet fuel treated with the cetane improver (JF+0.12vol%). The purpose of the research was to investigate the possibility to use of military jet F-34 fuel in the land-based direct injection diesel engine and examine the effect of F-34 and F-34 fuel treated with 0.12vol% 2-ethylhexyl nitrate on the autoignition delay, combustion, performance, emissions and the smoke opacity.
The maximum cylinder gas pressure produced from fuel JF and JF+0.12vol% was lower 4.3% and 2.8% at speed of 1400 rpm, and 2.5% and 5.7% at speed of 2200 rpm compared to 86.6 MPa and 82.5 MPa of the normal diesel. At rated 2200 rpm speed, the use of the jet fuel treated with the cetane improver led to smoother engine performance under all loads and the maximum cylinder pressure gradients were reduced by 9.4% as against 15.9 bar/deg of the normal diesel. The minimum brake specific fuel consumption (bsfc) for F-34 fuel and treated F-34 fuel was decreased by 4.8% and 3.5% at 1400 rpm and increased by 2.7% and 3.7% at 2200 rpm compared to 249.5 g/kWh and 251.8 g/kWh of the normal diesel.
Maximum NO emissions produced from JF fuel and JF+0.12vol% fuel were reduced by 11.5% and 7.0% at 1400 rpm, and 17.1% and 17.3% at speed of 2200 rpm compared to 1705 ppm and 1389 ppm emanating from the normal diesel. Maximum CO emissions were suppressed by 39.3% and 16.8% compared to 4988 ppm produced from the normal diesel running at 1400 rpm speed. At speed of 2200 rpm, the ecological effect of using F-34 fuel was minimal and the CO emissions sustained over the whole load range at the same level and increased by 2.5% and 3.0% with regard to the normal diesel operating under high load. The HC emission was correspondingly 78.3% and 58.8% lower for the low and high loads compared to 230 ppm and 1820 ppm of the normal diesel running at speed of 1400 min-1. The smoke opacity produced from fuels JF and JF+0.12vol% sustained at lower levels over the whole load range with the maximum values being 14.6% and 8.1% lower with regard to 94.9% of the normal diesel operating at speed of 1400 rpm. The experimental test results showed that military jet F-34 fuel is a cleaner-burning 85 replacement of the diesel fuel and suggests better fuel economy with reduced all harmful emissions, including NO, NO2, NOx, CO, HC and smoke opacity of the exhausts.