In the past few years the standards for pollutant emission on Diesel Engines in Brazil, especially regarding NOx and Particulate Material, have suffered drastic reductions. These reductions have been driven by international legislations and the fact that Proconve P6, equivalent to Euro IV, has been skipped in Brazil due to the unavailability of low sulfur fuel (50ppm and 10ppm), so now Proconve P7, equivalent to Euro V, would be implemented in 2012.
The reductions imposed by Proconve P7(Euro V) as opposed to Proconve P5 (Euro III) the current emission legislation, determines a reduction of 60% on NOx and 80% on Particulate Matter (PM), imposing new challenges in emission control. Those emission levels can only be achieved through significant changes in the engine's hardware and the use of different after-treatment systems like the Particulate Filter (CDPF) and the Oxidation Catalyst (DOC), also using low sulfur fuel.
However, with the constant demands for better fuel consumption by the commercial vehicles customers, and also the use of diesel fuel for the regeneration process of the particulate matter in CDPF, a optimization of fuel injection strategies to control the in-cylinder combustion events become necessary.
Multiple fuel injection strategies in Diesel engines can reduce engine noise, combustion pressure and the most important, it can improve the trade-offs between NOx and PM. This paper presents test results from a Heavy-Duty Diesel Engine with EGR, demonstrating the efficiency of the multiple injection strategy, reducing the emission of Particulate Material without compromising the low NOx levels achieved through the low temperature combustion, characteristic of engines with EGR. Also utilizing less particulate filter regenerations and reducing fuel consumption as a result.