After-Treatment Systems to Meet China NS VI, India BS VI Regulation Limits

Cold-Start WHTC and WHSC Testing Results on Multi-Cylinder Opposed-Piston Engine Demonstrating Low CO ₂ Emissions while Meeting BS-VI Emissions and Enabling Aftertreatment Downsizing

“…To achieve acceptable tail pipe emissions on a composite WHTC transient cycle, it is important to have sufficient engine out exhaust temperature particularly during cold start portion of the WHTC cycle. With sufficient exhaust temperature, early urea dosing can be enabled, as well as NO2/NOx ratio can be improved to allow high NOx conversions [4]. On Achates Power OP Engines, the catalyst light-off (CLO) operating mode, is activated at cold start wherein the engine calibration is modified to rapidly raise the exhaust gas temperature to enable the SCR to reach its light-off temperature as fast as possible.…”

“…Conventional four-stroke engines typically need to implement thermal management during the hot start portion of WHTC when the system temperatures are cooler than the light off temperature requirements. The need for thermal management to meet BS-VI emissions on conventional four-stroke engines is discussed in elaborate detail in [4]. The thermal management mode in four-strokes is typically enabled as and when the catalyst bed temperature drops below a pre-defined temperature threshold.…”

“…The European Stationary Cycle (ESC) and European Transient Cycle (ETC) are replaced with the World Harmonized Steady-State Cycle (WHSC) and World Harmonized Transient Cycle (WHTC). These new cycles (WHTC and WHSC) are more representative of real-world driving conditions and are therefore more appropriate for evaluating the emission performance of the regulated vehicles [4]. The regulatory emissions limits on WHSC and WHTC emission cycles are specified in Table 1 [4].…”

“…These new cycles (WHTC and WHSC) are more representative of real-world driving conditions and are therefore more appropriate for evaluating the emission performance of the regulated vehicles [4]. The regulatory emissions limits on WHSC and WHTC emission cycles are specified in Table 1 [4]. Learning from the success in US 2010 and Euro VI applications, China NS VI/ India BS VI solutions will also use the 4-way emission control systems with DOC, DPF, SCR and ASC technologies [4].…”

“…The regulatory emissions limits on WHSC and WHTC emission cycles are specified in Table 1 [4]. Learning from the success in US 2010 and Euro VI applications, China NS VI/ India BS VI solutions will also use the 4-way emission control systems with DOC, DPF, SCR and ASC technologies [4]. This will not only add substantially to aftertreatment cost but also add to engine backpressure leading to a CO 2 emissions' penalty.…”