Factors affecting fuel consumption of tractor operating active tillage implement and its prediction

Fuel consumption and power take-off (PTO) power requirement were measured for a 33.8 kW two-wheel drive tractor when used for operating a 1.6 m rotavator with 36 “L” shaped blades in sandy clay loam soil at an average soil moisture content of 8.8 ± 1% (dry basis) at IIT Kharagpur, India. Field experiments were conducted for a tractor with rotavator at seven different engine speeds (between 35 and 75% of full throttle engine speed), gear settings (L2 and L3) and depths of operation (60, 80 and 100 mm). Depth of operation, engine speed and gear setting were found to affect the fuel consumption of tractor. For the same PTO power consumption, lesser fuel consumption of tractor was observed in gear up conditions. A variation from −3.60 to −19.67% was observed while comparing the observed fuel consumption values with those predicted by the American Society of Agricultural and Biological Engineers (ASABE D 497.7) model. These variations were due to non-inclusion of gear settings in the ASABE fuel consumption model. Hence, an attempt was made to modify the ASABE fuel consumption model by incorporating gear settings in terms of speed ratio (peripheral speed of the rotavator to forward speed of the tractor i.e. u/v ratio). The developed fuel consumption model comprising engine speed, PTO power consumption and u/v could predict the observed values with a variation of ±6%.