GM: Chevy Volt Won't Be Labeled Zero-Emission - or 230 MPG
By Michelle Krebs April 13, 2010Engineers leading development of General Motors Co.'s 2011 Chevrolet Volt extended-range 
electric vehicle through its final stages told reporters the car will be "right up there with (GM's) most emissions-efficient vehicles," but will not be certified by the Environmental Protection Agency as a zero-emissions vehicle, as are pure battery-powered vehicles.
Also: fuhgeddabout that 230 miles-per-gallon city-cycle fuel economy rating GM so controversially touted last summer. Although GM's Volt engineers aren't saying it won't happen, they said the number was based on a preliminary fuel-economy measure proposed by the EPA for vehicles like the Volt and that the actual fuel-economy rating methodology is still to be decided.
But listen between the lines and it's clear the 230-mpg claim - rumored to be hotly disapproved by Volt developers when the company and then-CEO Fritz Henderson gaily hyped it last August - almost certainly will not be supported by whatever test methodology finally determines the Volt's official fuel-economy number. The 230-mpg number was outsized because of the Volt's ability to travel relatively long distances without burning any gasoline.
Andrew Farah, chief engineer for the Volt and the variant for GM's Adam Opel AG European unit, the Opel Ampera, said the 230-mpg figure was based on GM's knowledge of the EPA's thinking in preliminary talks about the Volt.
Calculating the fuel economy of the Volt is a particularly difficult job, Peter J. Savagian, engineering director, hybrid powertrain systems engineering, told AutoObserver, because of the many variables involved with its "blended" strategy of electric and internal-combustion operation.
The Volt is designed to run up to 40 miles only on power from its onboard batteries, which can be plugged into the electric grid for recharging. But unlike pure battery-electric vehicles, the trip is not over if battery power is depleted. Instead, the Volt's "range extending" design calls on the car's small gasoline engine to start, acting as a generator to create electricity for the batteries in order to keep the Volt moving, perhaps as much as an additional 300 miles.
Savagian is part of a Society of Automotive Engineers group advising the EPA on the best method for measuring - and translating to customers - the fuel economy of new-technology vehicles that operate of varying degrees of electrification. He said the SAE group is striving to determine the best method of correlating the energy usage of electrified vehicles with existing measures of fuel economy for conventionally powered internal-combustion vehicles.
The SAE group is working to develop not just an accurate fuel-economy testing methodology, but also window stickers that will convey to consumers what kind of "mileage" they might expect from vehicles like the Volt, battery-only electric vehicles such as the upcoming Nissan Leaf, and an expected wave of plug-in hybrid vehicles.
In the case of the Volt or plug-in hybrids with enough battery capacity to deliver meaningful electric-only driving range, Savagian said the group is likely to recommend to the EPA a window sticker that indicates city and highway fuel economy for operation when using the internal-combustion engine, as well as city and highway ratings for electric driving. He said he also favors a sticker that shows electric-only driving range, plus a simple grid to demonstrate probable fuel-economy for various driving ranges. - Bill Visnic, Senior Editor
Photo by GM
GM will back off last summer's controversial boast that the Chevrolet Volt will achieve 230 mpg.
LEAVE A COMMENT
I like Savagian's ideas for rating fuel economy of partially electric vehicles like the Volt. The simple grid I especially think is a good idea, but my fear is that some bureaucrat will nix the idea as needlessly complicated.
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