If you are environmentally-conscious or your government some strict laws imposed, you want to drive a green car. It looks like making the choice is simple – you just go through the specs of a car and choose the one that if fuel-efficient. However, a car, which consumes little gasoline, is not necessarily green as the new study from the University of Toronto has revealed.
Why this came into the attention of scientists? Well, trends of automotive industry are very clear – automakers are trying to hit several birds with one stone – making car fuel-efficient should mean it is cheaper to own and better for the environment. This trend is mostly based on gasoline direct-injection (GDI) technology, which saw a huge growth between years 2009 and 2015. Scientists wanted to see if GDI is always the greener choice and thus the study was started.
Scientists found that in terms of CO2 emissions, GDI engines are in fact less harmful for the environment. However, these engines emit more of black carbon, better known as soot, which contributes to climate-warming processes, and more other toxic compounds. Study showed that out of all vehicles tested, GDI engines rank in 73rd percentile for black carbon and 80-90th percentile for these volatile toxic organic compounds. This can completely cancel gains of reducing CO2 emissions, but, according to scientists, it depends on fuel composition, temperature and lifetime of the vehicle.
Zimmerman, lead author on the studies, said: “We found that in some cases, you need up to a 20 per cent improvement in fuel economy in order to offset black carbon emissions. Offsetting the black carbon might be realistic in a place like California, where fuel composition is more strictly regulated and seasonal temperatures fluctuate less, but is harder to achieve in Canada.”
An older technology, port fuel injection or PFI, can also be compared to GDI. New GDI is much more fuel efficient than PFI from ten years ago, but the difference is minute comparing a modern GDI with PFI from five years ago. This makes scientists question the technology and motifs behind choosing one or another – while some technologies may be greener, some may provide better fuel efficiency, which is a better selling point.
These findings are very interesting. However, having in mind how quickly technologies are being implemented in today’s automotive industry, it will not take long for GDI to be replaced with other systems. It is important that automakers would consider the bigger picture of the impact their cars are going to have on the environment.