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:

  • John Deere Power Systems (JDPS) announced that their PowerTech PSX 13.5L diesel engine has been certified as compliant with EPA Tier 4i/EU Stage III B emissions regulations and will go into production in March 2011. The engine uses cooled EGR and a diesel particulate filter for NOx and PM control and features full-authority electronic controls, a 4-valve cylinder head, a high-pressure fuel system, series turbocharging and an air-to-air aftercooling system. Deere’s 6.8L above 130 kW (174 hp) and 9.0L engine models had been certified to these standards in 2010.
  • MTU showcased its solutions for EPA Tier 4i and Tier 4f for construction equipment and industrial applications. Series 400, 500 and 900 Tier 4i engines up to 560 kW (750 bhp) will use SCR. New Series 1000, 1100, 1300 and 1500 Tier 4f engines will be introduced beginning in 2014 that will be equipped with EGR, SCR and diesel particulate filters, however, the development goal for these engines is to fulfill Tier 4f requirements without a diesel particulate filter. Series 1600 Tier 4f engines up to 730 kW (980 hp) will be equipped with EGR and a diesel oxidation catalyst but with a development goal of fulfilling Tier 4f requirements without any aftertreatment. New generation Series 2000 and Series 4000 engines will be introduced that use only in-engine technology and no exhaust gas aftertreatment to meet EPA regulatory requirements up to Tier 4f. Earlier in the month, MTU announced it would be showcasing its new-generation EPA Tier 4i Series 2000 and Series 4000 diesel engines for oil and gas applications at OTC May 2-5, 2011 in Houston, TX. For this application, no aftertreatment is used as well.

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