It seems there's a fork in the road with engine emissions regulations. As compliance for Tier 4 Interim approaches at the beginning of 2011, engine manufacturers are already announcing their plans for engine platforms.
Interim Tier 4 emission levels are a 90% reduction in particulate matter and a 50% reduction in nitrogen oxides (NOx) Engines 174 hp and above must be Interim Tier 4 compliant by 2011, and engines ranging from 75 hp to 174 hp must be Interim Tier 4 compliant by 2012.
With their introduction of three new row crop series earlier this year, AGCO has chosen to use selective catalytic reduction (SCR) technology for Interim Tier 4 and Final Tier 4 regulations. These AGCO Sisu Power engines use SCR technology (over-the-road trucks use similar systems), which are Tier 3 compliant and poise the tractors to be Interim Tier 4.
Engines that use SCR technology treat emissions after the combustion process is finished. In a catalytic converter the nitrogen oxide is mixed with the DEF and nitrogen and water are the only final emissions.
The DEF used in the SCR engines will be a 32% aqueous ammonia solution. It's expected that the DEF tank will need to be refilled at every other diesel tank fill up. AGCO dealers will stock DEF in 2.5-gal. jugs, and it should also be available through retailers serving the on-road truck market as well.
Cummins announces its 4-cylinder QSB3.3 and QSB4.5 engines, which range from 75-hp to 160-hp, will meet EPA Tier 4 Interim off-highway emissions with lower emissions achieved by using cooled Exhaust Gas Recirculation (EGR) for NOx control and exhaust aftertreatment for removing particulate matter. The 4-cylinder models were built with a more compact and simplified version of the Tier 4 Interim technology for the 6-cylinder QSB6.7 engine.
The High Pressure Common Rail (HPCR) fuel system employed on the Tier 3 QSB3.3 and QSB4.5 is already capable for Tier 4 Interim and will require no major change. An upgraded turbocharger with electronic control will be utilized to manage EGR flow across the entire engine rpm range. These engines retain the same 3.3- and 4.5-liter platforms and will be supplied as a fully integrated air-intake-to-exhaust system. The particulate aftertreatment replaces the muffler in the exhaust stream and offers equivalent noise reduction, and it can be installed vertically or horizontally.
John Deere will build on its technologies employed to satisfy Tier 3 regulations to further restrict emissions for Interim Tier 4. The company's compliant engines will feature cooled exhaust gas recirculation (EGR) and an exhaust particulate filter. The horsepower range will be 75 hp and higher, and the power range includes 4.5L, 6.8L, 9,0L and 13.5L in-line, four and six cylinder engines.
John Deere engines have been outfitted with EGR and variable geometry turbocharger equipment since 2005 with the Tier 3 regulations.