Author ORCID Identifier
Semester
Spring
Date of Graduation
2026
Document Type
Thesis (Campus Access)
Degree Type
MS
College
Statler College of Engineering and Mineral Resources
Department
Mechanical and Aerospace Engineering
Committee Chair
Hailin Li
Committee Co-Chair
Almoutazbellah Kutkut
Committee Member
Cosmin Dumitrescu
Committee Member
V'yacheslav Akkerman
Abstract
Cold-start NOx emissions control remains one of the most challenging issues for Heavy-Duty (HD) diesel engines. The low exhaust temperatures delay the activation of aftertreatment components, particularly selective catalytic reduction (SCR) systems, leading to elevated NOx emissions. This study numerically investigates the combined potential of a generator–battery–electric heating system and generator torque management in improving cold- start tailpipe NOx emissions from an HD diesel engine equipped with an advanced aftertreatment system. The integrated engine, generator, battery, electric heater (EH) and aftertreatment models were developed in GT-SUITE and calibrated against steady-state and transient experimental data obtained from 2021 Navistar HD diesel engine. Unlike conventional approaches that rely solely on external electrical heating, this work introduces a thermo-electrical strategy in which generator torque is increased to simultaneously raise exhaust temperature and generate electrical energy to power the heater, with a battery to store the energy. A key contribution of this study is the identification of a break-even operating point at which the generated electrical energy equals the electricity consumed by heater, eliminating the need for external energy input. In addition, this study provides a quantitative evaluation of the trade-off between NOx reduction and fuel consumption under transient driving conditions. The simulation framework evaluates system performance over FTP and City driving cycles. Results show that increasing generator torque increases exhaust temperature, accelerates catalyst light-off, improves SCR conversion efficiency, and increases the engine-out NO x emission while also increasing fuel consumption. For the combined FTP cycle, tailpipe NOx emissions decreased from 4.4 to 3.3 g/cycle, corresponding to a 25% reduction, with a fuel penalty of 455 g and a 9.8% increase in fuel consumption, resulting in 413.5 g diesel per g NO x reduced. For the combined City cycle, tailpipe NO x emissions decreased from 19.6 to 10.3 g/cycle, achieving a 48% reduction, with a fuel penalty of 922 g and an 18% increase in fuel consumption, corresponding to 98.9 g diesel per g NOx reduced. The reduced tailpipe NOx emissions were due to the improvement in SCR efficiency. The application of an electrical heater improved the SCR efficiency at FTP cycle from 94.5% to 96.2%. In comparison, the SCR efficiency at City cycle was improved from 82.8% to 93.9%. These findings demonstrate that the proposed integrated strategy can reduce cold-start NOx emissions while providing insight into the energy–emissions trade-off, supporting the development of more efficient thermal management strategies for future low-emission diesel engines.
Recommended Citation
Rashid, Mahatab Bin, "A Numerical Investigation of Potential of a Generator-Battery-Electric Heater System in Improving Heavy-Duty Diesel Engine NOx Emissions" (2026). Graduate Theses, Dissertations, and Problem Reports. 13352.
https://researchrepository.wvu.edu/etd/13352
Comments
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