19 November 2007
Cummins announced its technology path to meet US EPA Tier 4 interim and European Stage IIIB mobile off-road emission standards across the 175-750 hp (130-560 kW) powerband, which take effect in 2011.
“Core technology” will be diesel particulate filter (DPF) and cooled exhaust gas recirculation (EGR). The DPF will reduce PM emissions by 90%, while EGR will reduce NOx by 45%. Engine enhancements will also include the use of variable geometry turbochargers (VG Turbo), advanced electronic controls and high pressure common rail fuel systems. The engines will be also equipped with a crankcase filter which eliminates escaping blowby gases, oil mist and droplets.
Common Tier 4 subsystem architecture will extend from the MidRange QSB to the Heavy-Duty QSX engines. The Cummins Tier 4 product range will maintain or increase power outputs compared to Tier 3. Cummins intends to improve fuel efficiency by up to 5%, depending on rating and duty cycle.
The particulate filter technology is based on the DPF systems for 2007 highway engines. For Tier 4 applications, Cummins is factoring in off-highway requirements such as high-shock loads, angularity, space restrictions and working environment conditions.
The Tier 4 “interim” standards for 130-560 kW engines require a PM level of 0.02 g/kWh and NOx of around 2 g/kWh. The final Tier 4 and the EU Stage IV regulations require NOx of 0.4 g/kWh from 2014. Cummins has not yet decided on the NOx control options for 2014.