Driving a Chevy Volt Test Mule

GM recently announced that the 2011 Chevrolet Volt could score 230 mpg in the EPA city fuel economy cycle and well into the triple digits for combined driving. Though the final EPA test methodology for vehicles that will plug into the electric grid has yet to be finalized, 230 mpg is GM’s best guess estimate given the EPA’s current criteria for plug-in hybrids and extended range electric vehicles.

Test Mule

The numbers game GM is playing here is only accurate if you drive the exact distance that the EPA will use in the test. Drive beyond that and the Volt’s fuel economy will begin to drop with every additional mile you drive. Once the battery reaches a 30-percent state of charge and the gasoline engine fires to provide electricity, the Volt will deliver approximately 50 mpg and fuel economy will gradually go down until the car is recharged. If you drive less than the Volt’s 40-mile electric range, however, GM’s revolutionary car won’t use a drop of gasoline, so gasoline mileage isn’t even a factor.


We recently had the opportunity to drive the latest Chevy Volt test mule around GM’s Warren, Michigan Tech Lab compound. The current Volt mules are based on the European Chevy Cruze sedan. GM’s Global Delta II platform due to replace the Chevy Cobalt in North America in the 2011 model year, and is very close in size and weight to the Volt, making it more suitable as a test mule than the first generation Chevy Malibu mules.


At this stage of testing, the Volt mules are operating strictly in the battery supplied electric mode. Integration of the gasoline generator should happen in the next phase of testing. Still, the driving experience is representative of how the Volt will drive because unlike hybrids that most consumers are familiar with, the Volt is propelled solely by electric drive. GM’s Voltec powertrain utilizes the gasoline engine purely as a means to generate electricity, not to directly propel the car.

Pre-Production Volt

Like other electric drive vehicles, power delivery is smooth and positive. Without an internal combustion engine running, noise, vibration, and harshness levels are easier to manage. Since the Cruze has a different body structure than the production Volt and the test mules aren’t as polished as a production product, there was no way to gauge just how quiet the Volt will be. We expect that it will be very pleasing to drive. Once the gas engine fires to make electricity, dynamics will change, but the transition should be manageable since the engine will generally run at a constant rpm and not cycle on and off as much as a hybrid.