Fig. 4 shows the ratio of driving axle torque, fuel consumption,
working hours, and tillage depth by gear selection to L2. The ratioof the driving axle torque was averaged torque of sum of all driving
axles.
When the gear was raised from L2 to L3, the axle torque increased
by 28%, whereas the fuel consumption decreased by 13% due to
the decrease of working hours by 33%. The tillage depth decreased
by 2%, but the decrease was not significant between L2 and L3
gear. It is known that the performance of tractor with L3 gear was
higher than that with L2 gear. Also, when the gear was raised from
L2 to L4, the axle torque increased by 71%, whereas the fuel
consumption decreased by 22% due to the reduced working hours.
Therefore, the result showed that the fuel efficiency was high
with higher gear set because higher gear set reduced working
hours. However, at gear L4, the tillage depth gear decreased
seriously, which implied that the regular work cannot be done
with excessively higher gear.