ENGINE SYSTEM: AFTERTREATMENT
AFTERTREATMENT SYSTEM Designs Will Evolve to Meet Customer and Emissions Requirements
The cross section of a compact, fully insulated Stage V/Tier 4 Final DOC+DPF+Mixer+SCR system.
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Increasingly stringent emissions regulations and customer needs will bring about the need for new aftertreatment system technologies. By Sara Jensen
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ftertreatment systems have become an integral component of engines today due to the implementation of increasingly stringent emissions regulations. “In the last decade, aftertreatment systems used by our global OEM customers have become increasingly complex and more densely packaged,” said Korneel De Rudder, Development Manager, Europe at Donaldson Co. This increased complexity is necessary to meet the ever-tightening emissions standards being implemented in the U.S., Europe and other parts of the world he said. “As a result, there are more catalysts and sensors incorporated into a given package size,” De Rudder explains. “For many off-road machines, because under-hood space is limited, we need to be creative to fit these new components onto the machines–and the components need to be more densely packaged.” Donaldson has focused on developing components and systems which allow for less “dead” volume JO
Engine manufacturers continue to advance aftertreatment and engine designs to meet current and future emissions regulations.
inside the afterteatment system. “With earlier generation systems, ‘dead’ volume was often used to increase the residence time of the DEF (diesel exhaust fluid; also called AdBlue), which enhanced its decomposition and mixing in the exhaust gas,” he said. Determining how to develop and use the aftertreatment system is integral as well, said Alex Eden, Product Marketing Manager for Small Engines at Perkins Engines Co. Ltd. Manufacturers can choose to have a smaller diesel particulate filter (DPF) and larger selective catalytic reduction (SCR) or vice versa. They can also choose to focus their development efforts on the combustion system to make it a very clean system, which helps to reduce emissions and can help reduce the size of the aftertreatment system. “You have to think of aftertreatment
as part of the entire system and take a systems approach that looks at satisfying the customer’s need for power, product, price and packaging, while also meeting emissions standards. Mark Borst, Product Marketing Manager for Large Engines at Perkins Engines Co., said that when Tier 4 Final came into effect in the U.S., the company chose to include a DPF on its larger engines even though it was not required to meet the regulation. The company felt including a DPF was beneficial for meeting the emissions regulation and allowed it to commonize its engines once the EU’s Stage V standard was put in place. “OEM customers buying our engines, Tier 4 Final or Stage V, get the same installation. They know the size, they know the package, they know what they have to accommodate,” said Borst. “Aftertreatment is just as integral to their machine as it is to our engine.”
Recent advancements in aftertreatment systems
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Eric Hruby, staff engineer, Power Unit Development at John Deere, said that since the implementation of Tier 4 Final, the company has worked on advancing its aftertreatment system designs based on real-world experiences and customer feedback. “Our efforts have been focused on improving customer value in vehicle integration, visibil-
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OEM Off-Highway | MARCH/APRIL 2022
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