In CPCB-IV+ Emissions regulations NOx & PM are reduced by 90% from CPCB-II limits in the power band 56 < kW ≤ 560. Obvious technology approach adopted by industry to meet this requirement is the introduction of CRDI fuel injection system & DOC+SCR+ASC aftertreatment technology, leading to substantial modifications at both engine & genset level. This result into huge development expenditure, high incremental product cost, timelines and increased total cost of ownership. This paper describes the frugal technology approach to keep development cost, product cost, development time to the minimum using electronically governed, high pressure mechanical fuel injection equipment, with DOC+SCR+ASC without any external thermal management strategy while comfortably achieving target CPCB-IV+ emission levels. This integrated approach also helped in completing the entire development in < 12 months.
1D-thermodynamic & 3D-combustion simulation approach was adopted to predict the engine out emissions and to optimize combustion hardware. This was followed by Virtual Test Bench (VTB) or closed loop HiL system simulation to integrate the engine, after-treatment plant models, actuators, sensors, ECU, ACU, GCU & RMS. In VTB lab, all the corresponding software’s communication was established and most of the NCD functionalities were verified before moving on to the actual test bed activities. The matured dataset from VTB and hardware selected through simulation were further taken up on the engine testbench and engine out calibration. As per the engine out & tailpipe emissions targets and engine out performance conditions, required exhaust aftertreatment was selected through benchmarking, technology potential analysis, which is to be DOC+SCR+ASC and without any external thermal management strategy i.e. intake throttle valve, HC dozer etc. same was taken care by engine out optimization and TC to DOC inlet exhaust gas temperature drop by thermal insulation. Further, DOC+SCR+ASC system was optimized through 1D & 3D CFD simulations for Uniformity index, back pressure, thermal mapping, Urea deposits and SCR conversions prediction etc. After freezing the EATS design, tailpipe/ SCR calibration was carried out.
Through this approach CPCB-IV+ emission norms could be met with NOx emissions min. of 50% margin, PM emissions min. of 30% margin. NCD regulations met with single NCD family, while maintaining best in class fuel & DEF consumption levels.