Variability in Measured Real-World Operational Energy Use and Emission Rates of a Plug-In Hybrid Electric Vehicle

H Christopher Frey,Xiaohui Zheng,Jiangchuan Hu

doi:10.3390/en13051140

H Christopher Frey, Xiaohui Zheng + Show 1 more

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https://doi.org/10.3390/en13051140

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Journal: Energies	Publication Date: Mar 4, 2020
Citations: 19	License type: CC BY 4.0

Affiliation: North Carolina State University

Abstract

Compared to comparably sized conventional light duty gasoline vehicles (CLDGVs), plug-in hybrid electric vehicles (PHEVs) may offer benefits of improved energy economy, reduced emissions, and the flexibility to use electricity as an energy source. PHEVs operate in either charge depleting (CD) or charge sustaining (CS) mode; the engine has the ability to turn on and off; and the engine can have multiple cold starts. A method is demonstrated for quantifying the real-world activity, energy use, and emissions of PHEVs, taking into account these operational characteristics and differences in electricity generation resource mix. A 2013 Toyota Prius plug-in was measured using a portable emission measurement system. Vehicle specific power (VSP) based modal average energy use and emission rates are inferred to assess trends in energy use and emissions with respect to engine load and for comparisons of engine on versus engine off, and cold start versus hot stabilized running. The results show that, compared to CLDGVs, the PHEV operating in CD mode has improved energy efficiency and lower CO2, CO, HC, NOx, and PM2.5 emission rates for a wide range of power generation fuel mixes. However, PHEV energy use and emission rates are highly variable, with periods of relatively high on-road emission rates related to cold starts.

Highlights

Plug-in hybrid electric vehicles (PHEVs) have the potential to lower carbon dioxide (CO2 ) and criteria pollutant emissions and to improve transportation energy efficiency and sustainability [1,2].Compared to battery electric vehicles (BEVs), some vehicle purchasers prefer Plug-In Hybrid Electric Vehicle (PHEV) because they can have lower total ownership cost, depending on the price of gasoline, and have the driving range advantages of conventional vehicles [3]
Results are presented based on North Carolina (NC), with sensitivity analysis for other states. These emission factors are based on the annual average energy mix and assume that PHEVs are charged at a random time of day
A field study was designed and conducted to focus on key sources of variability in the energy use and emission rates related to PHEV operations, including power demand, charging mode, cold start and hot stabilized operation, and electricity generation resource mix

Summary

Introduction

Plug-in hybrid electric vehicles (PHEVs) have the potential to lower carbon dioxide (CO2 ) and criteria pollutant emissions and to improve transportation energy efficiency and sustainability [1,2]. Compared to battery electric vehicles (BEVs), some vehicle purchasers prefer PHEVs because they can have lower total ownership cost, depending on the price of gasoline, and have the driving range advantages of conventional vehicles [3]. PHEVs with relatively modest all-electric range (AER) can support a high percentage of electric-only operation for the daily needs of many users, while provided the capability for gasoline-powered hybrid electric operation for longer-range driving. The relatively small AER of PHEVs compared to BEVs is associated with a much smaller battery. PHEVs have advantages over BEVs and conventional light duty gasoline vehicles (CLDGVs)

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