30 March 2012
At its Darlington Technical Centre in the UK, Cummins revealed its technology path for Euro VI (2013) engines and unveiled two new generation, Euro VI engine models: the ISB4.5 and ISB6.7.
The engines will use a combination of cooled exhaust gas recirculation (EGR) and variable geometry turbocharging (VGT) with a new aftertreatment system incorporating a diesel particulate filter (DPF) and selective catalytic reduction (SCR). A Cu-zeolite formulation is used to maximize NOx conversion efficiency at low temperatures. The technology has been developed based on the experience from Euro IV, Euro V, US EPA 2010, as well as nonroad EU Stage IIIB and IV. It is likely to be the final step in NOx and PM emissions reductions—said Cummins—given the 99% reduction to date since Euro I began in the 1990s.
The addition of a particulate number limit at the Euro VI stage has driven all manufacturers to use particulate filtration in their exhaust systems, noted Cummins. Euro VI also includes a number of other new features that place more challenges on engine manufacturers. The move to the World Harmonized Transient and Stationary Cycle (WHTC and WHSC) testing that focuses on lower speeds and loads makes it more difficult to maintain the operational efficiency of aftertreatment, with efficiency being closely linked to the heat management of the system, said Cummins. The EU is introducing portable emissions measurement systems for in-service vehicle testing. Engines must not exceed 1.5 times the laboratory emissions levels for 7 years or 700,000 km. The in-service testing will be backed up by more stringent on board diagnostic (OBD) regulations. New OBD limits for Euro VI will be phased-in from 2013 to 2015.
ISB4.5. Available at up to 210 hp for truck installations and 200 hp for bus installations, the new 4.5 liter, 4 cylinder engine delivers a peak torque of 760 Nm. Composite materials are used for components such as the valve cover and oil pan to reduce weight and noise. The product changes enabled the engine to be approximately 10% lighter than the current product, despite the addition of cooled EGR and VGT technologies.
Balancing of the EGR and SCR systems allowed to optimize the fuel and urea (Adblue) consumption. Cummins expects Adblue usage will be at 2-3% of diesel consumption, down from the 5-7% level typical for Euro V engines.
Euro VI requires engines use closed crankcase ventilation (CCV) systems, as blow-by gases are included in the emissions measurement. The ISB4.5 uses a patented design which is integrated into the camshaft with no servicing required.
ISB6.7. The 6.7 liter, 6 cylinder engine range extends up to 310 hp for truck and coach installations and 280 hp for bus applications. Peak torque remains at 1100 Nm.
This latest version of the engine builds on the pedigree of the B5.9 and ISBe 6.7 engines, with the addition of the EPA 2010 engine technology of cooled EGR with variable geometry turbocharging. The VGT can also function as an exhaust brake, allowing the OEM to remove cost from their system.
A further emissions improvement is the new CCV system mounted to the engine valve cover. The engine also features a new nanotechnology-based filter media for the engine’s fuel system, removing up to 98.7% of all particles down to 4 microns.