Think a more fuel-efficient engine is the green choice? Maybe not

Trying to think green when buying a car? Whether your new fuel-efficient engine helps or hurts the warming planet depends on where you live and what you’re putting in the tank, shows new research out of U of T Engineering.

New cars aim to deliver high performance with maximum fuel efficiency, making them easier on both the environment and the wallet. To do this, auto manufacturers are adopting a smaller, more fuel-efficient engine type, called gasoline direct-injection (GDI) — between model years 2009 to 2015, the percentage of new vehicles sold with GDI engines jumped from five to 46 per cent.

But research led by Professor Greg Evans (ChemE) in the University of Toronto’s Faculty of Applied Science & Engineering shows that GDI isn’t necessarily the greener choice. Although GDI engines emit lower levels of CO2, they emit more black carbon — the climate-warming particles commonly known as soot — and toxic volatile organic compounds, such as benzene and toluene. Read full story.