Volt: What About the Gas?

As gasoline prices begin to rise, the idea of a vehicle that uses exceedingly little gasoline—like the Chevy Volt—might become more appealing.

As gasoline prices begin to rise, the idea of a vehicle that uses exceedingly little gasoline—like the Chevy Volt—might become more appealing.

And as winter begins to wind down, the idea of the gasoline that you forgot to drain from your power mower becomes more disturbing.

The fact of the matter is that gasoline if not used ages. Which can cause performance problems.

So what about the Volt? Assuming that you (1) have it fully charged and (2) drive it the 35 miles or so that the batteries allow, it is possible that you’re not going to use the gasoline in the 9.3-gallon tank.

What’s more, gas sitting in a gas tank tends to evaporate over time, and the usual approach to handling that is with a charcoal canister that traps the evaporating gas, then feeds it back to the fuel tank. But if the gas might not be used for an extended period of time, that canister could excessively fill up with the vapors.

2

So GM engineers did a few things. Like create a pressure-sealed steel fuel tank. Steel because it had to handle pressure that the more common plastic tanks used for cars couldn’t.

Volt engineers and the tank supplier, Spectra Premium, developed the tank with a 1.4-mm hot-dipped tin-zinc coated steel (coated both sides). Just in case there are a mechanical pressure relief valve that opens at 3.5 psi and a vacuum relief that opens at -2.3 psi. This tank keeps the fuel from evaporating and keeps humidity out.

All good. But what about aging?

Well, it turns out that there is a “maintenance mode.” If the engine hasn’t been started for six weeks, a message is sent to the driver. This can be ignored for 24 hours, after which the car will start the engine so as to use up gasoline and keep the engine components lubricated.

And if there should be a situation where the 9.3 gallons haven’t been used during an entire year, the fuel maintenance program will run the engine until the gas is used up or until fresh gasoline is added to the tank.

As Jon Stec, fuel system integration engineer for the Volt, put it, “For the driver who starts the year with a full tank of 9.3 gallons and runs 15,000 miles on electricity, the maintenance mode will use just enough gas to average a very respectable 1,613 miles per gallon.”

Of course, the driver might be struck down by sticker shock at the pump after that period of time.