An experimental fuel efficiency meter

Abstract

The use of a meter that displays instantaneously to the tractor operator on a continuous basis the fuel efficiency of his tillage operation, would make possible the observation of the change in efficiency and the effect on the tillage operation when changes in field condition occur. The operator would be able to make adjustments and immediately observe the effect on efficiency in order to keep the efficiency as high as possible. The selection of a best size machine and adjusting the speed and depth to improve fuel efficiency should not affect the quality of tillage. Trying to maintain the efficiency as high as possible means higher power output at a lower fuel consumption. Therefore, cheaper operation can be achieved. Fuel efficiency is the drawbar horsepower of the tractor (constant x load x speed) divided by the power input (amount of fuel consumed). In view of this, an efficiency meter was constructed and tested. The meter electrically calculated the efficiency from the outputs of three transducers measuring draft, speed and fuel consumption. An electrical resistance strain gage dynamometer, a d.c. tachometer generator and a turbine meter were used to determine the load pulled by the tractor, the actual speed of the tractor and fuel consumed by the tractor engine respectively. The linear characteristics between the variable being measured and the output of each of the three devices listed above have the advantage in making a fuel efficiency meter simpler to design. A low cost vortex flowmeter that can be used on Agricultural tractors for the measurements of fuel consumption was built and tested. The meter showed a linear measuring characteristic and that the frequency of rotation of the contained ball depends mainly on the density of the ball and track radius. During a field test draft measurement compared favorably with another type of pull meter and the percent error in fuel efficiency measurement is probably small compared to the human error in attempting to estimate an average value of the reading being taken, mainly because of the instantaneous variation in draft.