Emissions from Plug-in Hybrid Electric Vehicles (PHEVs) During Real World Driving Under Various Weather Conditions
Plug-in hybrid electric vehicles (PHEVs) are regarded as a key technology in reducing the impact of internal combustion engines on air pollution and greenhouse gases. PHEVs have the advantage in market penetration due to its lower cost and higher driving range, as compared to electric vehicles (EVs). On the other hand, PHEVs still emit air pollutants due to the presence of an internal combustion engine.
This study aims to understand emissions from PHEVs, focusing on real on-road driving conditions. PHEVs turn off an already warmed-up engine when the battery is charged enough during CS (charge sustaining) mode. This characteristic leads to energy efficient driving, but the engine can have multiple cost-starts, which can increase engine emissions unexpectedly. This study aims to understand emissions from PHEVs, including: 1) on-road emission characteristics; 2) cold-start and cold-restart; and 3) cold-cold-start and cold-cold-restart. (Cold-cold-start and cold-cold-restart tests will be done below freezing temperatures to understand ambient temperature on the emissions of PHEVs.) The study also plans to understand the trade-offs between battery use and emission reduction.