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.
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“Higher compression makes more power. However, the Volt’s 1.4 liter “range extender” is not a high performance engine.”
Seriously? Higher Compression makes more power per unit of fuel. Therefore it’s more efficient. That is why it is used in high performance engines. More power from less displacement means less weight. It also means better fuel mileage.
If they want to get the best fuel mileage they can out of the Volt, the range extender damn well better be a high performance engine.
“Higher compression makes more power. However, the Volt’s 1.4 liter “range extender” is not a high performance engine.”
Seriously? Higher Compression makes more power per unit of fuel. Therefore it’s more efficient. That is why it is used in high performance engines. More power from less displacement means less weight. It also means better fuel mileage.
If they want to get the best fuel mileage they can out of the Volt, the range extender damn well better be a high performance engine.
MaxHedrm is right, they should make that small 1.4L engine as powerful as they can. Heck, they should have made a 1.0L Turbocharged Direct Injected Diesel motor, but us Dumb Americans don’t seem to like Diesel………
MaxHedrm is right, they should make that small 1.4L engine as powerful as they can. Heck, they should have made a 1.0L Turbocharged Direct Injected Diesel motor, but us Dumb Americans don’t seem to like Diesel………
Like any other car it can run on regular gas, but will run much better on premium.
Like any other car it can run on regular gas, but will run much better on premium.
Josh:
You are right! I am just glad that someone else out there feels the same as me.
And i hate this discussion i’ve seen it a million times. premium fuel does not mean more power, it doesn’t mean “better” it is just the oil industry adding names to something to make people think it is better.
Josh:
You are right! I am just glad that someone else out there feels the same as me.
And i hate this discussion i’ve seen it a million times. premium fuel does not mean more power, it doesn’t mean “better” it is just the oil industry adding names to something to make people think it is better.
“And i hate this discussion i’ve seen it a million times. premium fuel does not mean more power, it doesn’t mean “better” it is just the oil industry adding names to something to make people think it is better.”
Not necessarily, it has a higher octane, meaning it resists predetonation. If your engine is tuned for high octane (higher compression ratio and valve timing to take advantage of that), then using regular will result in lower power and poorer fuel economy (as the engine’s computer will retard the spark timing to prevent predetonation, that is, engine ping or knock).
If your engine is tuned for regular (like most cars), then you’re right, premium won’t help at all and can actually result in poorer fuel economy.
If you’re a manufacturer and will be designing an engine to get the maximum fuel economy, then designing it around premium fuel is best because you can design a higher compression ratio and tune the computer to run a bit leaner. When I read that the Volt took premium, it made perfect sense to me as mostly well-to-do people will be buying the Volt, so the price for premium is a non-issue. Besides, most of the time it will be run in electric-only mode, so my guess is the average Volt owner will buy fuel very rarely.
“And i hate this discussion i’ve seen it a million times. premium fuel does not mean more power, it doesn’t mean “better” it is just the oil industry adding names to something to make people think it is better.”
Not necessarily, it has a higher octane, meaning it resists predetonation. If your engine is tuned for high octane (higher compression ratio and valve timing to take advantage of that), then using regular will result in lower power and poorer fuel economy (as the engine’s computer will retard the spark timing to prevent predetonation, that is, engine ping or knock).
If your engine is tuned for regular (like most cars), then you’re right, premium won’t help at all and can actually result in poorer fuel economy.
If you’re a manufacturer and will be designing an engine to get the maximum fuel economy, then designing it around premium fuel is best because you can design a higher compression ratio and tune the computer to run a bit leaner. When I read that the Volt took premium, it made perfect sense to me as mostly well-to-do people will be buying the Volt, so the price for premium is a non-issue. Besides, most of the time it will be run in electric-only mode, so my guess is the average Volt owner will buy fuel very rarely.
I’m thinking maybe GM was pushing the premium fuel requirement to foster the belief this is a high-end luxury vehicle.
They still need to get that electric range extended.
I’m thinking maybe GM was pushing the premium fuel requirement to foster the belief this is a high-end luxury vehicle.
They still need to get that electric range extended.
Yeah. This is true, if you can afford the $41,000 Volt, you can probably afford the fuel too.
Some people have more money than common sense and need to get the next great thing to be the first to have it.
Yeah. This is true, if you can afford the $41,000 Volt, you can probably afford the fuel too.
Some people have more money than common sense and need to get the next great thing to be the first to have it.
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