April 20, 2011 – New Canaan, CT
It may seem ironic, but the World’s first Extended Range Electric Vehicle, the Chevy Volt, required significant engineering effort to design a suitable gas tank. Why? Since the Volt can routinely go weeks or longer without using a drop of gasoline, steps had to be taken to ensure the small supply of gas in the extended range generator’s tank would not evaporate or go bad.
Any traditional gasoline powered vehicle doesn’t have to think about such concerns; but the Volt is designed and engineered to travel approximately 40 miles per charge without using any gas. Since national statistics show that over 70 percent of Americans drive 40 miles or less per day, the Volt has the potential to save all those consumers their weekly gas bill. Of course, whenever a Volt driver wants to travel further than 40 miles, the onboard gasoline powered generator automatically starts up and produces electricity to keep the car going.
But back to the gas tank. Traditional gas engine vehicles are constantly running their engines and because they feature charcoal canister systems that trap fuel vapor and route it back to the engine, these vehicles do not need to worry about fuel evaporating or going bad. Since the Volt can go so long between generator engine start-ups, the natural fuel vapor could reach dangerous levels. So Chevy’s engineers designed a special sealed fuel tank for the Volt.
This all new tank, developed in conjunction with Spectra Premium Inc, uses a tin-zinc-coated steel tank that resists corrosion from both the inside and outside rather than the plastic fuel tanks found in other vehicles. The Volt’s new tank, which holds 9.3 gallons of gas, also contains a mechanical pressure-relief valve that can act as a fail-safe in the unlikely occasion it is needed. Thus when you go to refuel the Volt’s gas tank, you must press a fuel door release button located on the driver’s door panel before unscrewing the gas cap. This special button releases the pressure inside the fuel tank so you can open the cap. If you are standing outside the Volt when this button is pressed, you will actually hear the pressure release.
OK, that takes care of pressurizing the Volt’s fuel system to help keep it safe and keep the fuel from evaporating. But what about the fuel just going bad? Many consumers don’t realize that gasoline has a shelf life. The reality is that any gasoline powered vehicle goes through a tank of gas well before that matters. But a Volt owner may find it takes months or more to use up a tank of gas.
Thus, the Volt also features a ‘maintenance mode’ that comes into play if the gas generator engine has not been started in six weeks. First, the system will alert the driver that the engine needs to run for maintenance purposes, including making sure its internal components are properly lubricated. Then, the driver can either enable the engine to run, or defer the maintenance for up to 24 hours, after which the engine will just turn on by itself the next time the Volt is started. In addition, if a driver goes a full year without filling up the gas tank, the system will come on and run the Volt’s generator engine until all of the old gas in the tank is used. This forces the driver to go fill up the tank with fresh fuel.
Think about it: How cool would it be to reduce your gas station visits to once per year?!?!? The bottom line, according to Jon Stec, Fuel System Integration Engineer for the Chevy Volt, “For the driver who starts the year with a full tank of 9.3 gallons and drives 14,600 miles on electricity, the maintenance mode will use just enough gas to average a very respectable 1,570 miles per gallon.”