A few days ago a story made the rounds on the Internet (as they usually do) that raised a few eyebrows regarding the Chevy Volt. GM’s much-ballyhooed plug-in hybrid, which can go 40 miles on electricity only, would apparently require premium gasoline to power its battery generator. Premium fuel carries a premium price, usually 20-30 cents more per gallon. So much for saving money on gas.
Turns out that yes, the Volt is calibrated to run on premium fuel, for reasons I will get into below. However, it is equipped with a knock sensor… which means the engine can “detune” itself to run on regular fuel.
Premium fuel is often required in high performance vehicles as a way of bumping up the compression ratio in the engine. Higher compression makes more power. However, the Volt’s 1.4 liter “range extender” is not a high performance engine. So it didn’t make sense to have it run on premium fuel when you are selling an expensive car under the premise of using as little fuel as possible.
GM has several reasons for using premium fuel. It burns better for one, resulting in fewer tail pipe emissions. Gas also loses its octane rating the longer it sits around; perhaps GM is under the impression that users won’t be using all that much gas, so it might be sitting in the gas tank for awhile. There might even be a psychological aspect to the premium fuel decision. If you are paying more for gas, you might be less inclined to use it, meaning people will really stretch those 40 miles of electric-only range out.
I still think it’s rather bogus all around, but I’m no engineer either. If you can afford the $41,000 Volt, you can probably afford the fuel too.
Source: AutoBlog | Image: GM
Chris DeMorro is a car enthusiast, blogger, and all-around crazy man who is as passionate about hybrids as he is about Hemis. You can follow his constant misadventures at Three Months In A Mustang.