Equipment World Digital Magazine
Issue link: https://read.dmtmag.com/i/107622
tier 4 | continued the need for in-use regeneration, since the particulate emissions are prevented in the combustion process. The DOC in the module strips out hydrocarbons and particulates. It connects to an injector and mixing tube where the SCR goes to work spraying the exhaust gases with a urea-based diesel exhaust fluid (DEF) which reduces the NOx levels by more than 90 percent before it exits the exhaust pipe. Compact in size, the DOC/ SCR system is ideally suited for smaller machines such as backhoes, telehandlers, forklifts and mid-sized excavators, says Daniel Clayton, Perkins Tier 4 product marketing manager. For customers who might be weighing the difference between the twin turbo 1204F-E44TTA and a six-cylinder engine, Perkins also offers a service-free DOC/DPF/ SCR aftertreatment option. This setup allows the engine to come closer to the transient performance of a six-cylinder engine while still yielding some space savings. If you reduce NOx in cylinder, you sacrifice some fuel efficiency. But to reduce NOx with the SCR, you use diesel exhaust fluid (which costs roughly about the same as diesel fuel). Per- kins "optimizes" its SCR delivery systems to give you the best balance of emissions reductions and DEF usage, Clayton says. In keeping with the maintenance-free goals of the DOC/ SCR system, the DPF module mentioned above is also maintenance free up to the normal core engine overhaul point. The chart below shows where the various emissions control strategies appear in the Perkins Tier 4 Final lineup, with a DOC/ DPF predominating in the sub74 horsepower categories, and the various combinations of SCR technology taking over from 75 horsepower and up. PERKINS TIER 4 FINAL ENGINE SPECIFICATIONS HP ENGINE MODEL FUEL INJECTION TURBO 0-24 402F-05 Mechanical N/A 403F-07 Mechanical N/A 403F-11 Mechanical N/A 403F-15 Mechanical N/A 403F-15T Mechanical Single 403F-15T Mechanical 404F-22 DOC/DPF Mechanical N/A N/A DOC/DPF 404F-22T Mechanical Single NRS DOC/DPF High pressure Single NRS DOC/DPF 1204F-E44TA High pressure Single NRS DOC/SCR High pressure Two-stage NRS DOC/SCR High pressure Single NRS DPF/DOC/SCR 1206F-E70TA High pressure Single NRS DPF/DOC/SCR 1206F-E70TTA 174-751 N/A 1206F-E70TA 75-173 Single 1204F-E44TTA 49-74 AFTERTREATMENT 854F-E34T 25-48 NRS High pressure Two-stage NRS DPF/DOC/SCR 50 February 2013 | EquipmentWorld.com