More Field Work From Less Fuel

With lower crop prices across the board, farmers are looking to cut production costs without lowering production efficiency. Choosing a new Tier 4 tractor with a good fuel efficiency rating can help them see fuel efficiency that’s up to 15% better than tractors offered a few years ago.

Fuel efficiency ratings can range from 19 horsepower hours per gallon to 14/hp-hr/gal. or below, depending on the size of tractors. The higher the rating, the better the fuel efficiency. According to University of Nebraska Tractor Test Laboratory statistics and assuming diesel fuel is priced at $4/gal., a difference of just one hp-hr./gal. point can translate into an annual cost savings of $1,300 for a 200-hp tractor used 500 hours a year. (see Farm Industry News Nov. 2011 issue).

U.S. EPA exhaust emission regulations have likely held back better fuel efficiency, says Terry Hlavinka, vice president of Hlavinka Equipment Co., which operates a large Case IH dealer network in southeast Texas.

“Tier 1, 2 and 3 tractors caused engines to emit fewer emission but didn’t help fuel efficiency,” Hlavinka says. “Tier 4 was really the first time that an engine introduction had engines that were more fuel efficient. We have seen a 7-15% better fuel economy with the Tier 4 interim engines.”

It gets down to measuring both diesel fuel efficiency, as well as diesel exhaust fluid, adds Jarrod McGinnis, division marketing manager, John Deere 7 and 8 series tractors. “We‘re trying to educate customers that fuel efficiency no longer matters – it’s fluid efficiency,” McGinnis says. “Every engine burns diesel fuel and diesel exhaust fluid. So farmers need to look at both of those.”

The Nebraska tractor test reviews virtually every tractor marketed in America. Numerous countries offer tractors for sale in the U.S. And with the rainbow of tractor colors, not just red or green, it takes time. With new engine requirements and many tractors equipped with engines a central manufacturers, there are often only small differences between tractor fuel efficiency.

“When we (Case IH) introduced Tier 4 tractors, our 4WD, 600-hp engines were able to obtain 17 hp-hrs/gal., compared to 14-15 for two major competitors,” Hlavinka says. “Also, our 4WD 350 hp tractors had a rating of about 17 hp-hrs gal., compared to about 16 for competitors. We aim to be 10% more efficient after consideration of cost DEF (exhaust fluid).

“Tier 4 was the first time we had an EPA compliance issue that provided a positive return for our customers. The industry is on schedule to have to change one more time by going to Tier 4 final next year.”

“No, matter what size tractor, with fuel and fluid consumption, we’re talking about single digit percent differences,” says John Deere’s McGinnis.

Development of engines that meet EPA guidelines and provide needed power for row-crop tractors hasn’t happened overnight. “Our path has been a building block approach,” McGinnis says. “We use (exhaust gas recirculation) EGR and diesel oxidation catalyst (DOC) technology and added selective catalytic reduction (SCR).

“Our 7R tractors have new engine solutions that will burn 2% less total fluid than the Interim 4 solution. We are adding diesel exhaust fluid, but still burning less diesel fuel to where we have at least a 2% improvement in fuel efficiency.”

Match tractors to the job and tillage system. Willard Downs, University of Missouri agricultural engineer, says that in the past decade or so, many farmers have shifted to more conservation tillage. Many promote better fuel savings seen in conservation tillage practices.

“Overall, power requirements needed for field operations haven’t changed that much,” he says. “But with fuel prices what they are, people should be giving thoughts to that. Diesel may be down right now, but prices can fluctuate heavily.

“What really has changed in the past 15-20 years are the control systems. There have been substantial improvements in engines, transmissions and drivetrains. That has added to fuel efficiency.”

Downs says more stringent environmental regulations on fuel purity may help fuel efficiency. “There is cleaner fuel and fewer residuals in the fuel, such as reduced sulfur in diesel,” he says. “Fuel burns more efficiently.”

He says estimating the amount of fuel used in farming operations will help select the best conservation practices for farm equipment. He co-authored (with R.W. Hansen) a report on “Estimating Farm Fuel Requirements.”

“Tractors use an average of only 55-60% of their maximum horsepower on a year-round basis,” he says in the report. “You select the most fuel-conserving method by comparing different tillage methods and cropping systems.

“With increasing concern for fuel conservation and energy management, farmers may wish to estimate the amount of fuel required to perform specific farming operations. By knowing the amount of fuel used, farmers can select the best conservation practices to manage farm equipment.”

For example, to disk a field, the gallons of fuel per acre for that field are nearly constant regardless of the size disk and tractor used. “For the same operation, differences due to equipment are quite small,” Downs says. “Therefore, the fuel used per acre for any specific operation can be assumed to be constant except for small variations due to soil types, moisture content and depth of operation.”

Downs says a tractor-disk combination with an average 100 hp at the drawbar for five hours delivers 500 hp-hrs of energy for the disking operation. Since it is not practical for farmers to measure drawbar horsepower, energy requirements normally are based on rated maximum power takeoff horsepower (PTO-hp).

Diesel tractors deliver an average of 13.0 PTO-hp-hrs/gal; gasoline, 9.0 hp-hrs/gal; and LP gas, 7.5 hp-hrs/gal. A diesel tractor rated at 100 maximum PTO-hp operating at full load uses 7.69 gal/hr. 100 hp / 13.0 hp-hrs./gal = 7.69 gal./hr. On the same basis, a 100-hp gasoline tractor uses 100 / 9.0 or 11.1 gal/hr and an LP gas tractor, 100 / 7.5 or 13.3 gal/hr.

McGinnis says that when it gets down to fuel sayings, farmers probably look more at the best time to buy fuel. “Controlling fuel costs likely gets down to knowing when to fuel the tanks,” he says.

“The North American market is probably concerned more about dealer support and tractor performance than fuel or fluid efficiency. But Europeans pay one to two times more for fuel, so they are concerned.”

Hlavinka adds, “I’m not sure if there are many operators large enough to justify a major tractor purchased based solely on fuel savings. I think it’s more of a factor or whether you want to choose one brand or another or pay $10,000 for one brand or another.”