19 August 2008
Reversing its earlier technology approach, Cummins announced that it will add selective catalytic reduction (SCR) aftertreatment to its Heavy-Duty engines for 2010. Initially, Cummins intended to use the SCR technology on MidRange engines, and no NOx aftertreatment on Heavy-Duty engines.
The addition of SCR to Heavy-Duty engines is necessary to deliver better fuel efficiency. “The addition of the new SCR catalyst technology ensures that Cummins will deliver the best fuel economy in the industry and total operating cost benefits to our customers”, said Cummins.
Cummins’ Heavy-Duty ISX engine family will also incorporate the XPI fuel system, cooled exhaust gas recirculation (EGR), variable geometry turbocharger, particulate filter, and advanced electronic controls.
The approach not to use NOx aftertreatment was in part based on utilizing NOx emission credits that would be accumulated by Cummins by 2010. This strategy—made possible by the early launch of 2010-compliant 6.7 liter engine used in the Dodge RAM pickup trucks—might have been compromised by the recent slump in the sales of Dodge heavy pick-ups.
Navistar appears to remain the only heavy-duty engine manufacturer who intends to meet the 2010 emission standards (NOx = 0.2 g/bhp-hr, PM = 0.01 g/bhp-hr) with no NOx aftertreatment. Other manufacturers have opted for urea-based SCR technology.
Cummins Emission Solutions will supply integrated exhaust aftertreatment systems for Cummins Heavy-Duty and MidRange engines.