Development of future efficient and cleaner heavy duty engines are no longer limited to laboratory development under standard conditions. In order to address the global issues like climate change and poor air quality in its true sense, future advanced and existing heavy duty diesel engines should also be demonstrating emission conformity compliance as per legislations under real driving conditions using PEMS testing. In India starting from Apr 2023, heavy duty vehicles would be tested for in-service conformity and presently they are under monitoring phase. With the introduction of RDE (Real Driving Emission) the effort, cost and time requirements could be tremendous in order to meet conformity compliance over real driving conditions including the range of ambient conditions for the said period as per the norms. Hence, it would be of great importance if we can utilize virtual test bed (VTB) to off-load several initial field testing and calibration efforts by virtually running the vehicles over simulated cycles with various operating conditions that includes simulating payload, traffic, ambient condition change and predicting emissions and their conformity for these generated routes and operating conditions. However, this would indeed require a good correlation between the actual engine and vehicle behavior and the plant model. In this work an attempt has been made to understand how VTB can be used for this purpose. The PEMS testing data for the first heavy duty vehicle with GVW above 12 ton was used for one level of model validation were reasonable matching of various trip parameters, characteristics trends and emissions were observed for running the simulated cycle in VTB. Later we performed a parametric variations including payload, traffic and ambient conditions using a second vehicle with GVW above 12 ton category with different tonnage and application to understand their impact on trip characteristics, emissions and conformity factors and finally the results for one parameter was validated by conducting a PEMS test. With this approach, in contrast to conventional method we utilized virtual test bed with integration of engine ECU, plant model (engine +after treatment) and PUMA test system to investigate the possibility of generating drive cycle, performing parametric variations, simulating extreme conditions and understanding their impact on trip characteristics, emissions, and conformity factor moreover such findings will definitely help in understanding the scope of calibration work required to comply with real driving emission norms.
