Reduction Rates of Fuel Consumption by Gear Up and Throttle Down on an Agricultural Tractor

We investigated the effect of operating conditions such as travel gears, PTO gears and engine speed of a 24kW agricultural tractor on fuel consumption. In the indoor tests, we found that as the PTO power and the engine speed increased, the fuel consumption increased and the fuel consumption per power hour became minimum when loads corresponding to 70-90% of the maximum power were applied at each engine speed. In the field tests, the fuel consumption was reduced by shifting to a higher travel and PTO gear and by lowering engine speed. The reduction rates of the fuel consumption by gear up and throttle down compared with those at full throttle were about 15 to 30% with PTO power at 55% of maximum engine output, about 30 to 40% with PTO power at 30% of maximum engine output, about 30 to 45% with PTO power at 20% of maximum engine output, and about 40 to 50% with PTO power at 15% of maximum engine output. In the road tests, the reduction rates of the fuel consumption by gear up and throttle down compared with those at full throttle were about 30 to 50% for traveling at 10 km/h, and about 20 to 35% for traveling at 15 km/h.