BULGARIAN JOURNAL OF AGRICULTURAL SCIENCE, vol.16, no.4, pp.526-533, 2010 (SCI-Expanded)
The objective of this study was to determine differences between the standard 540 rpm power take-off (PTO) revolution in tractors and its alternative, namely "the economical PTO revolution (540E)." Loads were applied to three tractors (JD 5625, NH TD85, MF 3085) with similar technical specifications, by means of a PTO dynamometer (Eddy-current) under laboratory conditions. Measurements were made of tractor PTO torque, engine fuel consumption, specific fuel consumption, and engine exhaust gas and cooling water temperatures on the basis of load (power kW) steps applied at a constant PTO revolution of 540 rpm. Data analysis showed an average fuel saving was performed with the 540E PTO of 27.18%, 18.62% and 15.88% for the JD 5625, MF 3085, and NH TD85 tractors, respectively. Fuel savings decreased with the increase in PTO load. Engine-PTO speed rates were also found to be effective in fuel saving. The torque values for the three tractors varied directly proportionally to the increase in the PTO load steps. Exhaust gas temperature data showed that coercions had occurred in the tractor engines when certain load values were exceeded when using the 540E operation (35 kW, 20 kW, and 30 kW, respectively for JD 5625, MF 3085, and NH TD85 tractors). In conclusion, the economical PTO operation was shown to have important advantages, particularly in terms of fuel and specific fuel consumptions for many power-driven machines.