Princeton University

School of Engineering & Applied Science

Electrifying ground transportation: Hybrids and challenges for combustion engines

Professor Michael E. Mueller, Princeton University, Mechanical and Aerospace Engineering
Friend Center, 109
Monday, April 7, 2014 - 7:30pm

Electrification of personal ground transportation has the potential to significantly reduce CO2 emissions. Currently, in the US, transportation (the majority of which is personal ground transportation) accounts for 28% of our energy usage yet 34% of our CO2 emissions. This discrepancy is due to an almost exclusive reliance on the combustion of fossil fuels and the relatively low thermal efficiency of engines (~25%) used for transportation. While full electrification of personal ground transportation will remain elusive until battery technology becomes substantially more economical, partial electrification (hybridization) of personal ground transportation has become almost routine. Different types of hybrid powertrains will be introduced, and their relative advantages and disadvantages will be discussed. Furthermore, all hybrid vehicles use unconventional gasoline engines modified for higher efficiency, and the differences with conventional gasoline engines will be discussed. Finally, competing combustion engine technologies that can also lead to substantial CO2 reductions will also be discussed including diesel engines and homogeneous charge compression ignition (HCCI) engines.