Farm Industry News has published one of the first reports on what to expect from the new Interim Tier 4 tractors based on tests performed at the University of Nebraska Tractor Test Lab, and the message for farmers looking to reduce costs by buying a new tractor is: When calculating fuel savings, factor in additional requirements that are inherent to the newer engines’ designs.
According to the report, tractor manufacturers have taken two approaches to reduce the amount of soot and smog produced by their tractors in order to comply with the U.S. Environmental Protection Agency’s requirements for the Interim Tier 4 engines: “One requires the use of an engine after-treatment called diesel exhaust fluid (DEF), which is sprayed into the exhaust at a rate of 1 to 2 gal/hr. AGCO, Case IH, and New Holland are among the manufacturers using this strategy. The other strategy, called EGR, used by John Deere, recirculates the exhaust gas before it leaves the engine to burn up the soot. This re-burn cycle requires extra fuel, which John Deere says is normally less than 1% of the total fuel consumed.”
The Nebraska Test Lab established fuel efficiency ratings that factored in the additional fluid and exhaust treatment. The goal of the endeavor is to facilitate realistic comparisons between tractors, i.e., DEF versus EGR and Interim Tier 4 versus prior tiers. Here are the preliminary ratings.
According to Roger Hoy, director of the lab, “If you account for DEF consumption and fuel used during regeneration, you get a different landscape that is more meaningful than if you looked only at combustion fuel efficiency. Overall, I would say that Interim Tier 4 tractors are probably more costly than previous ones. That’s my personal viewpoint.”
The article stresses that it is important to consider these two factors:
1) “Please note that only the makes and models tested are included in this report. (. . . read tractor manufacturers’ explanations of the results relative to their respective models.) Other brands, including Challenger, Massey Ferguson, McCormick, Fendt and Versatile will be covered once more test results become available. Also, while this report focuses strictly on high-horsepower row-crop tractors rated 150+ hp, future reports will look at large 4-wd tractors and small tractors under 150 hp.”
2) “Fuel and fluid efficiency ratings for the story were based on “Drawbar Performance” at 75% of pull at maximum power to reflect performance during typical heavy fieldwork. But. . . ratings will vary according to the intended use of the tractor, so readers are advised to consider all operating points in the test when making comparisons.”