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Engine manufacturers unveil Tier 4 technologies at ConExpo

29 March 2011

The 2011 ConExpo/Con-Agg trade show, the world’s largest trade fair for the construction and construction materials industries, was held in Las Vegas, NV March 22-26 at the Las Vegas Convention Center. A number of engine manufacturers were present to unveil and/or showcase their nonroad Tier 4 technologies as well as some on-road developments relevant to construction equipment.

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With the unveiling of some Tier 4f strategies that continued to use a mixture of many of the same technologies used for Tier 4i, it is readily apparent that there is no one common Tier 4f solution that will emerge. Rather, Tier 4f will include a variety of technologies including cooled EGR, diesel particulate filters, diesel oxidation catalysts, SCR as well as technologies using no aftertreatment as well. A number of manufacturers unveiled SCR strategies, especially for larger engines, that no doubt will be attractive for applications where minimizing the engine’s fuel consumption is important. It is also apparent that across the entire range of engines from 37 kW (50 hp) and up subject to Tier 4f PM limits intended to force the use of diesel particulate filters, the PM standard can be met without one. Strategies that allow the PM limit to be met without a DPF include SCR only, cooled EGR with a catalyzed flow through particulate aftertreatment and for the case of engines above 560 kW (750 hp), possibly no aftertreatment at all. Details of some of the more interesting news items from the exhibition included:

When EPA promulgated the nonroad Tier 4 regulations, the intent was to force manufacturers to adopt wall flow diesel particulate filters for engines over 25 hp. With the various solutions that are emerging that use no diesel particulate filters, it is not clear what the US EPA’s reaction will be. If a further tightening of the particulate standards emerges, the most likely option would be to adopt particulate number limits as tightening of the mass-based PM limits is hardly possible due to the measurement challenges at ultra low PM concentrations.

Source: Engine manufacturers