Development of an Activity-based Windowing Approach to Evaluate Real-World NOx Emissions from Modern Medium and Heavy-Duty Diesel Trucks

Abstract

Development of an Activity-based Windowing Approach to Evaluate Real-World NOx Emissions from Modern Medium and Heavy-Duty Diesel Trucks The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only by vocations that experience sustained highway driving operation, which is not entirely representative of actual highly diverse real-world operation experienced by the engine/aftertreatment system. Evaluation of real-world driving emissions (RDE) plays a critical role in monitoring and ensuring the performance of emissions control systems. Portable emissions measurement system (PEMS) serves as a robust tool to assess emissions levels during real-world operation. However, utilization of PEMS for large-scale deployment is time-consuming, labor-intensive, and expensive. As a vision of potential elements for a next-tier of in-use NOx monitoring systems, there is an actively growing research and regulatory interest to evaluate the feasibility of using existing on-board NOx sensors for HD on-board NOx compliance. However, research studies have highlighted that NOx sensor measurements are also subjected to cross-sensitivity from other species in the exhaust stream. The journey towards completion of an exciting academic adventure has been a collaborative endeavor, where I would like to thank a huge group of people who have supported me with guidance, motivation, and opportunities as stepping stones to achieve professional growth. First and foremost, I would like to thank my parents Premnath and Ratnamala for providing me with their unconditional love, encouragement, endless support, and countless sacrifices in fulfilling every dream of mine since my childhood. This journey would not have been possible without the support of mom and dad, both emotionally and financially. Thank you for believing in me and always supporting me in my decisions, even through the most challenging times. vi temporarily moved to Detroit for my internship. You have always helped me get through challenging and difficult phases in life, and most importantly supported me with the important decisions of my life. Thank you very much. Special thanks to Ikttesh Chahal for your friendship since the time we met. Thanks for always offering me with your valuable advice whenever needed and believing in me that I had the potential to do more than I actually do and alwa...