ANALYSIS OF PERFORMANCE AND EMISSIONS OF THE EXHAUSTS OF OFF-ROAD DIESEL ENGINE OPERATING ON THREE AGENT ETHANOL, PETROL AND RAPESEED OIL BLEND

Abstract

The article presents comparative analysis of bench testing results of a four stroke, four cylinder, direct injection, unmodified, naturally aspirated diesel engine operating on rapeseed oil (RO) and its 7.5vol% blend with ethanol (E) and petrol (P) premixed in equal 50vol% (E) and 50vol% (P) proportions (EPRO7.5). The purpose of the research is to investigate the simultaneous effect of both agents on brake mean effective pressure (bmep), brake specific fuel consumption (bsfc), brake specific energy consumption (bsec), the brake thermal efficiency (bte) and emission composition changes, including NO, NO2, NOx, CO, CO2, HC and smoke opacity of the exhausts.

The bmep of the fully loaded, λ = 1.6, engine operating at the maximum torque 1800 min-1 mode and rated speed of 2200 min-1 on blend EPRO7.5 is higher by 1.0% and lower by 0.8%, respectively, comparing with that of RO (0.770 and 0.740 MPa). Brake specific fuel consumption changes against that of RO from by 1.1% higher level for easy load to lower by 3.7% for heavy load at 2200 min-1 speed. The brake specific energy consumption of the loaded engine from by 9.5% and 5.0% higher levels for low 1400 and 1600 min-1 speeds diminishes against that of RO by 3.3%, 5.8% and 4.3% for 1800, 2000 and 2200 min-1 speeds. The composite blend ensures maximum brake thermal efficiency 0.41-0.42 against that of RO (0.39) at 2000 and 2200 min-1 speed.

Maximum NOx emission emanating from three agent blend EPRO7.5 is from 27.7% (1951 ppm) to 2.1% (1546 ppm) higher comparing with that, 1528 ppm and 1514 ppm, from pure RO at 1400-2200 min-1 speeds. Both carbon monoxide CO emission and smoke opacity from the fully loaded engine operating on blend EPRO7.5 are lower by 28.6% (658 ppm) and 67.5% (23.4%) at low 1400 min-1 speed whereas for the rated 2200 min-1 speed, CO emission increases by 16.1% (692 ppm) and smoke opacity diminishes by 17.6% (23.9%) relative to corresponding data measured from RO.

The emission of HC is higher by 9-12 ppm, CO2 produced from blend EPRO7.5 amounts 7.9vol% and temperature of the exhaust remains nearly the same 510oC as that from RO at rated 2200 min-1 performance mode.