Ethanol in a Chevy Volt's gasoline back-up engine


Owners’ manual says to avoid oxygenates (ethers and ethanol), but all the pump gas in Colorado contains up to 10% ethanol. The Chevy dealer says all his customers use the pump gas and haven’t had ill effects. Any suggestions as to what the long-term effects might be?


^I suspect it may go stale quicker. I have to believe that ANY manufacturer in the US market makes their cars compatible with 10% ethanol–every OTHER Chevy is! Do you have the option of selecting ICE-mode, or does it only happen with battery depletion? It might be a good idea to see to it that you fill up at least once a month.


Since pretty much all gas is E10 I’d put in a bottle of Stabil each tank if I wasn’t filling up at least once every 2-3 months. Have you looked for ethanol free gas?


Has Chevy changed the primary purpose of the gasoline engine in the Volt?
In my opinion, the earlier incarnation of the volt is actually a hybrid touted as an electric car. The engine is actually integral to the functioning of the drivetrain under load. Masked in secrecy, it was almost impossible to uncover how it was implemented. Stating it as a backup leads me to question, have they changed? Or is the myth still ongoing??


Then and now, if driven normally, and less than the battery’s range, the gas motor often wouldn’t start the whole time.


That’s what I thought until I read some technical articles describing how the engine actually runs far more often that they originally claimed. I will go see if I kept the links…

BTW- the range is 38 miles (edit: I see it is now a whopping 53 miles for the next model year) on electric only- give or take. Once depleted, it runs on gas. How is that really any different than a classically defined hybrid? They run on electric until discharged and then run the gas engine to recharge the batteries. Potayto, potahto…

From Wiki-

The Society of Automotive Engineers' (SAE) definition of a hybrid vehicle states that the vehicle shall have "two or more energy storage systems both of which must provide propulsion power, either together or independently."[14] General Motors has avoided the use of the term "hybrid" when describing its Voltec designs, even after the carmaker revealed that in some cases the combustion engine provided some assist at high speeds or to improve performance.[15] Instead General Motors describes the Volt as an electric vehicle equipped with a "range extending" gasoline powered internal combustion engine (ICE) as a genset and therefore dubbed the Volt an "Extended Range Electric Vehicle" or E-REV.[16][17] In a January 2011 interview, the Chevy Volt's Global Chief Engineer, Pamela Fletcher, referred to the Volt as "an electric car with extended range."[18]


No, my hybrid runs on a combination of gas plus electric motor, seldom on electric motor except when coasting or low load constant speed. Call the Volt a hybrid, fine with me, but under its max range it runs on batteries most of the time.


there are several types of hybrid, don’t know which you call classical.

  1. Parallel hybrid, the electric engine is mechanically in parallel with the gas engine. They can both run for added power, or under gas only. Eg, Honda Insight

1a. TRR hybrid, ‘through the road’ type. Gas engine powers one axle, electric the other.

  1. Mild parallel hybrid. Has a smaller electric motor that is used for boost. Eg, Honda Civic Hybrid

  2. Power-split or series-parallel hybrid. These can run under electric only. The gas engine is coupled only to a generator, so the drive power comes only from the electric engine. Eg, Chevy Volt.

  3. Plug-in hybrid, is a subset of one of the above that allows the battery to be charged from the electric utility.


@BillRussell - the Volt (first gen, at least) actually had a direct drive motor-to-wheels connection, used when battery was depleted. Here’s Edmund’s description of the 4 modes involved. In mode 4 there’s a direct connection between the engine and the wheels:

"Mode 1: Low-speed electric-only mode up to 70 mph. The main traction motor-generator is turning, but it can only go so fast. Here the ring gear is locked so it can’t turn. The second motor-generator and the engine are disconnected and out of the picture. The main traction motor is left alone to drive the sun gear from battery power, which sets the planets in orbit. The orbit speed is sent out through the carrier and is proportional to vehicle speed.

Mode 2: High-speed electric-only mode up to top speed (100 mph). The engine remains dormant. Now the ring gear unlocks and is instead clutched to the second motor-generator, which is acting as a motor to set the ring in motion. With the sun already spinning, any rotation of the ring in the same direction will increase the overall orbit speed of the planets, which in turn increases vehicle speed beyond 70 mph.

Mode 3: Low-speed series hybrid mode up to 70 mph. Gasoline is now the base fuel that’s propelling the Volt in series-hybrid fashion. The battery has run down as far as the control system will allow. The ring gear is unlatched from the second motor-generator and locked in place as it was in Mode 1, and the main traction motor once again is solely responsible for making the planets orbit. But the electricity to do that now comes from the gas engine, which has been clutched to the second motor-generator, now in generator mode.

Mode 4: High-speed series-parallel hybrid mode up to top speed. This is classic gasoline-powered series-parallel operation. You can’t have both electric motors driving the car at high speed like we saw in Mode 2 because the battery is discharged, meaning that the second motor-generator must continue to be a generator driven by the engine. This is where the engine begins to directly drive the ring gear. The engine is already clutched to the second motor-generator, so a straight-through mechanical connection is established when the ring’s motor-generator clutch is engaged. Compared to Mode 3, the engine works harder here because it is simultaneously driving the ring gear and the shaft of the generator."

Owners' manual says to avoid oxygenates (ethers and ethanol), but all the pump gas in Colorado contains up to 10% ethanol.

There’s ONE and only ONE gas station within a 50 mile radius of where I live that sells non-oxygenate gas. I’ve seen several volts in this area…I’m pretty sure they’re not driving 50 miles to buy gas.


Yeah Bill, I should have been more clear in that definition of Classical…I was referring to the type whereby the gas engine only turns a generator to recharge the batteries…

the Volt (first gen, at least) actually had a direct drive motor-to-wheels connection, used when battery was depleted

That was their line until someone leaked that it was also enabled for certain performance conditions and was actually being used more often than originally claimed- see above. They wanted to differentiate themselves but IMHO, it bordered on deceptive…