With the start of the New Year, tractors and other nonroad vehicles with engines over 75 horsepower had to meet Tier 4 Final emissions standards established by the EPA to make the vehicles compliant with the Clean Air Act.
The Tier 4 requirements reduce the particulate matter (PM) and oxides of nitrogen (NOx) emissions of engines to a level that is 50-96 percent lower than those from previous diesel engines. Manufacturers have been phasing in the new requirements since 2011, and all new tractors must meet them. Used tractors built in earlier model years are grandfathered in and do not have to meet the requirements, but dealers can also sell inventories of equipment with engines that met the previous, Tier 3 standards until they are depleted. All Tier 4 engines have to use Ultra Low Sulfur Diesel Fuel (ULSD), which all over the road vehicles have been using since 2006.
Manufacturers had two choices for systems that scrub exhaust in compliance with Tier 4 Final, Cooled Exhaust Gas Recirculation (EGR) and Selective Catalytic Reduction (SCR). Case IH combine specialist Dan Kline said the implement maker used SCR right from the start at the previous adaptation level, Tier 4a; Case’s new axial flow combines, and Steiger and Magnum tractors, use SCR. He told Ozarks Farm & Neighbor, “We fine tune the engine to perform at its peak performance, and as it comes out of the engine we treat the emissions after the fact. We induce a little bit of diesel exhaust fluid (DEF) solution into the exhaust system; it allows us to mix into the exhaust stream and gets rid of the NOx, and puts out a clean system that meets the EPA requirements.”
DEF is a solution of 32.5 percent urea in deionized water. In the exhaust stream, it transforms into ammonia and converts NOx into nitrogen, carbon dioxide and water vapor. Kline said there’s a second, smaller tank for the DEF. “Depending on which Tier of emissions you’re at, you can run 1-2 tanks of diesel for every tank of diesel exhaust fluid,” he said. PM is removed inside the engine through a technology called Diesel Particle Filters. Case maintains its system reduces fuel costs by 10 percent, and overall operating costs by 1-2 percent.
Deere & Company uses both EGR and SCR, along with Diesel Particle Filters and a Diesel Oxidation Catalytic, in its engines. Deere Media Relations Manager Barry Nelson told OFN, “All the tractors we have introduced are Final Tier 4 compliant. All of the larger self-propelled machines including combines, sprayers, forage harvesters, tractors, etc., are also FT4 compliant.”
He recommended that buyers of new tractors ask their local dealers which system the tractor uses. Depending on the size of the machine, there are different Tier 4 Final Solutions; in addition to DEF, some require special maintenance. “Because of the new technology with engines and transmissions, we have been able to design tractors which are more fluid efficient while maintaining Final Tier 4 emissions standards,” he said.
Kent Brown, agricultural equipment business development manager at Kubota Corp, said all of the Japanese owned manufacturer’s tractors are Tier 4 Final compliant. “Kubota’s actually an innovator in the Tier 4 emissions,” Brown told OFN. “One of our slogans is ‘For Earth, for life,’ and that means cleaner emissions for everybody around the country. We’ve made sure we maintain the integrity of that emissions standard, and we’re meeting and exceeding that standard that the EPA has as of today.”


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