The system is said to be the first to introduce dual-dosing architecture to the truck industry, bringing a future-proof solution capable of meeting the next level of nitrogen oxide (NOx) levels proposed beyond current Euro VI emission levels and EPA regulations in North America, as well as helping to meet CO2 reduction goals.
The Dual-Dosing system applies two streams of urea (AdBlue) into the exhaust stream of a selective catalytic reduction (SCR) system to convert emissions into harmless vapour. The system is able to increase the effectiveness of NOx conversion during the low levels of heat at engine start-up and low-load running, with an additional benefit of enabling the engine combustion formula to reduce fuel consumption.
The three-year project was finished for the launch of the upgraded V8.
Robert Cochanski, general manager, Cummins Emission Solutions in Europe, Middle East and Africa, said: “It has taken thousands of hours of research and development, but I am delighted to say that the new system meets very demanding cold start conditions and operates robustly against harsh vibrations, achieving this while maintaining peak performance across a wider temperature range than previous systems.”
Now commercially available, the new Dual-Dosing system has a modular design adaptable to a wide range of engine displacements and SCR aftertreatment configurations. As both dosers act as a single, fully-synchronised system, the amount of urea injected (AdBlue or Diesel Exhaust Fluid) is equivalent to that of less-efficient single dosing systems of today. The system is designed for both low-flow and high-flow SCR systems, with the capability of meeting dosing rates up to 16 kg/hr.
The new Cummins Dual-Dosing urea injection system brings a new approach to resolve the NOx emissions control challenge resulting from low temperatures within the aftertreatment exhaust flow, according to the company. During cold cycle operations, the SCR-DPF aftertreatment becomes far less effective in reducing emissions as the reduced heat level adversely impacts the catalytic chemistry. This typically occurs under cold start conditions, low driving speeds, engine idling and with low ambient temperatures, representing a significant obstacle to meet extremely low emissions levels.
However, the dual-dosing design virtually eliminates any emissions spikes during cold cycle conditions by close-coupling the first doser at the turbocharger outlet. This utilises higher temperatures present as the exhaust stream exits the engine and enables the injected urea stream to maximize the emissions reduction. The second doser is located at the aftertreatment unit and operates when additional NOx reduction is required.
Testing of the system has demonstrated the ability to reduce NOx emission levels to around 50 percent below that of today’s regulations, providing a future-proof solution ready to meet the more stringent emission reductions likely to be proposed by the EU and EPA to take effect around the 2025 timeframe.
The system also brings a further benefit by enabling the engine combustion formula to reduce fuel consumption, as the need to generate excessive engine heat for the urea stream blending is eliminated. Depending on engine architecture and driving factors, this could improve fuel efficiency by 2-3%, says Cummings.