Date of Award


Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering-Engineering Mechanics (PhD)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Jeffrey D. Naber

Committee Member 1

Bo Chen

Committee Member 2

Darrell Robinette

Committee Member 3

Mufaddel Dahodwala


While many technologies such as electrically assisted turbocharging, exhaust energy recovery and mild hybridization have already proven to significantly increase heavy-duty engine efficiency, the key challenge to their widespread adoption has been their cost effectiveness and packaging. This research specifically addresses these challenges through evaluation and development of a novel technology concept termed as the Integrated Turbogeneration, Electrification and Supercharging (ITES) system. The concept integrates a secondary compressor, a turbocompound/expander turbine and an electric motor through a planetary gearset into the engine cranktrain. The approach enables a reduced system cost and space-claim, while maximizing the efficiency benefits of independent technologies.

First, an assessment of design alternatives for integration of the identified key engine technologies on a heavy-duty engine was conducted. Once the ITES concept was down selected, the research then focused on model-based optimization and evaluation of the ITES system for a downsized medium heavy-duty diesel engine applied in Class 6-7 urban vocational application. As an outcome of the evaluation, a 1D simulation based sizing methodology of ITES system components was proposed. Furthermore, a novel control strategy for the ITES system was developed that combines equivalent consumption based steady-state offline optimization with functional controls for transient operation and smooth mode switching. The offline optimization method was also extended to evaluate the potential of ITES system in increasing aftertreatment temperature, which is critical for meeting future ultra-low NOx emission standards. Lastly, using 1D simulation of validated models, the efficiency benefit of ITES system on engine certification and vehicle drive cycles was predicted for the Class 6-7 urban vocational application. In comparison to baseline engine, the downsized engine with ITES system predicted an 8.5% reduction in engine fuel consumption on HDFTP cycle, 19.3% increase in fuel economy on ARB Transient cycle and 23.7% increase in fuel economy on a real-world drive cycle.