By Jodie Wehrspann and Willie Vogt
Tier 4 final standards are the latest round of emission cuts mandated by the EPA. They are designed to reduce nitrogen oxides (NOx) by50% and particulate matter (PM) by over 90% over the previous round called Tier 3, which will bring those levels down to almost zero. This will be a major step in improving human health. Particulate matter, which consists of tiny particles and other contaminants, can affect how you breathe, causing asthma, allergies, and even lung cancer if inhaled at high levels. Nitrogen oxides are a cause of acid rain, which can lower crop yields by affecting the ozone. The new Tier 4 final engines will go a long way in reducing both those risks.
Farmers who already have purchased a vehicle powered by interim Tier 4 engines are by now past the shell-shock of these engines’ higher price tag. And, those same buyers also will know the basics of how to maintain these engines. That’s because Tier 4 final engines aren’t a whole lot different than interim Tier 4 engines from a maintenance standpoint, say the manufacturers.
Here is a company rundown of the maintenance steps you’ll need to take as the new Tier 4 final engines come on line January 1st. Check with your dealer on whether you need to use only ultra-low sulfur diesel (ULSD). Also, check the biodiesel blend limit, which is typically kept to a maximum of 7% biodiesel.
For final Tier 4 engines, John Deere is incorporating diesel exhaust fluid (DEF) to go along with its diesel particulate filter (DPF), diesel oxidizing catalyst (DOC), and cooled exhaust gas recirculation technology (cEGR) used to meet the interim requirements. The company introduced cEGR for use in engines of large agricultural tractors in 2005.
The technology being added, called selective catalytic reduction (SCR), is designed to work with the EGR to provide maximum “fluid” efficiency, the new metric that accounts for both the DEF and fuel use.
SCR is used by other companies, too. It injects a non-toxic blend of urea and water, called diesel exhaust fluid (DEF), into the engine exhaust stream. The catalyst breaks down the NOx in the exhaust and the ammonia found in the DEF, which then recombine to form nitrogen gas and water vapor. All of the DEF dosing and emissions monitoring is done by the engine. The extra step for the operator is filling a special tank with DEF at the same time as refueling. Deere says its DEF usage rates are 0.1 to 0.3 gal./hr., which equates to 1% to 4% DEF to diesel consumption.
A small DEF filter inside the DEF tank must be replaced every 1,500 to 2,000 hours depending on the machine. The EPA mandates that the DPF, part of the EGR system, must be serviced every 4,500 hours for machines larger than 175hp. The electronics onboard the machine notify the operator or dealer when the ash load warrants filter replacement.
Case IH says it is sticking with an “all SCR” approach that doesn’t use cooled exhaust gas recirculation or a diesel particulate filter. For 2014 the new engines, which are in the entire Magnum and Steiger lineup and some Axial-Flow models, will get a diesel oxidizing catalyst (DOC) to maximize SCR performance. It has a lifetime duty cycle. DEF can be added during refueling at a rate that is about 1.5% to 2.5% more than their existing Tier 4 interim solution, which Case IH says equates to every other fuel refill. A warning light will signal when your DEF tank is running low. Also, a cartridge filter inside the DEF module needs to be cleaned every 1,200 hours. Oil service intervals have been extended up to 600 hours, as allowed for by cleaner combustion.
Since New Holland and Case IH use the same Fiat Powertrain Technologies (FPT) Industrial engines, the maintenance requirements are the same for both companies (see above). As before, operators will have to fill the DEF tank every other time they refuel and change the DEF filter every 1,200 hours, as recommended. New Holland showcased its new Tier 4 final engines this fall on its new T7, T8 and T9 tractor series.
Agco unveiled the first of its Tier 4 final tractor engine lineup this fall with the launch of the Challenger MT700E and MT800E series tractors. Both series are equipped with Agco Power engines that are Tier 4 final compliant. Agco met the Tier 4 final standard using the SCR technology it introduced to the industry in 2009 and limited, cooled-EGR. Agco does not require the use of a particulate filter. DEF use is estimated to range from 7 to 9% of diesel fuel. Technology within the emissions system regulates and dispenses DEF at the rate needed, based on the load on the engine at the time. As with other SCR systems, operators are required to change the DEF filter, which Agco recommends you change every 1,200 hours.