Originally Posted by VOLDAR
No suss6052, it is not quite right what I underlined in your message. See here for a better explanation:
P.S. It requires premium, as you, me and everyone here uses in their Ford Focus. But the Volt needs gas rarely, depending on your drive. So, what's the point really ? The BMW i3 is not even close to what the Volt is.
Actually it does clutch in the planetary gear set, this has been stated by GM power train engineers, as it's much more efficient to run the car directly off gasoline at that point if there is a lack of electricity to run the car. Even if it was less than at 70 mph based on when it's more efficient it will use the gas engine directly through the electric motor rather than wasting the energy to convert the chemical energy into stored electricity in the battery.
It is essentially a Prius Plug in Hybrid electric or C-Max Energi driven primarily off the electric motor (100% of the first ~40 miles on a fully charged battery, then only partially the rest of the time).
The problem with the Volt requiring premium fuel is that as it's meant to be primarily an electric car it does not benefit performance wise from it, it merely allows the gas generator to remain stable for a long time of abuse without use, as well as to run somewhat high compression.
The volt needs 1 gallon of gas for every 40 miles of driving or sooner if used as a car for a road trip as I've personally experienced the Volt, driving one from North Carolina to Arizona. It is much less efficient than a Prius or C-Max in that case. Sure if you only drive 0-40 mi/day and can fully charge the car you will use less fuel, but you would use zero petrochemical fuel in a full electric car.
I like the Volt as a technical exercise, but the initial concept called for a 1.0 L I3 generator not the larger 1.4 L I4 because it was going to be a pure generator, not a means of direct propulsion
I am not against the volt, but it is odd that it needs premium fuel just to make 84 hp.