GM says Volt will be rated at 230 miles per gallon

The Chevrolet Volt - the electric vehicle General Motors Co is counting on to recharge its image with consumers - is on track to hit an unprecedented fuel economy rating of 230 miles per gallon in city driving, the automaker said Tuesday.GM Chief Executive Fritz Henderson said the Volt would get a "triple-digit" fuel economy rating for combined highway and city driving based on a draft standard