Conventional and Hybrid Powertrains

Summary

This chapter discusses the efficiency, fuel consumption, and range factors motivating the shift to electrification and the hybridization of the automotive powertrain. The emissions, fuel economy, and range of conventional gasoline and diesel vehicles are compared with the series and series‐parallel variants of the hybrid electric vehicle (HEV). A key enabling technology for the series‐parallel HEV is the continuously variable transmission (CVT), a power‐split device using epicyclic gears. The brake specific fuel consumption (BSFC) is a measure of the fuel consumption of an engine and is inversely related to the efficiency. The splitting of the engine power in a series‐parallel HEV is usually achieved using epicyclic gears arranged in a ring, sun, and planetary set. HEVs, such as the Toyota Prius and Chevy Volt, implement some form of CVT based on epicyclic gears. Vehicles such as the Hyundai Ioniq and Honda Fit use a competitive dual‐clutch multigear system in a parallel hybrid configuration.