A lot of press lately has been has circulating about the upcoming release of the Chevy Volt electric car. While I tend to be skeptical, and frequently critical of the automotive industry, this time I am critical of the critics. They don’t seem to understand the subject. And it’s easy to read a claim like 230 miles per gallon and just freak out.
When I was involved in the electric car industry, the parallel hybrid didn’t exist. It was considered to complex to be reliable and probably a lot less efficient, so no one was pursuing it. Leave it to our friends in Japan to master the ultimately complex and make it reasonable. More to their credit is that Prius owners who have been interviewed recently reported very high satisfaction with their car’s performance and reliability. Having reviewed the vehicle’s engine and controls architecture from SAE documents prior to it’s release, I was very concerned about how two complete drivetrain systems being controlled by 4 Power PC modules (each equal to a MAC laptop computer) would fare in the long haul. So far so good. Although I remain skeptical about who will fix them if they do break down. (me, skeptical?)
But the recent controversy about the Volt is really a problem because it is misinformed. The greatest feature of the car is it’s simplicity. It is a simple hybrid, a battery powered drivetrain with an engine generator to supplement the power required. Let me suggest a couple of equivalent technologies that us a similar drivetrain; the diesel electric locomotive and the two story tall 35 ton earth moving loader which have been around for decades. An on-board engine generator makes electricity and the wheels are turned by electric motors with gear reduction systems. The power train is completely drive-by-wire. No mechanical linkage from the engine to the wheel. Which makes engine operation extremely efficient.
In the case of the Volt there is an interposing technology, the lithium battery pack which will power the car with no fuel usage for 40 miles. So here comes the really tricky part. How many miles per gallon does it get? Well, the recently reported 230 miles per gallon has really raised some eyebrows. And I was pretty skeptical (surprised?) until I read the EPA discussion of methodology.
It’s simple. You start with 40 miles of battery capacity and no gasoline usage. If you drive 50 miles to work, depending on the drive cycle you might end up with 30 miles on battery, to maximize battery life, and 20 miles on gasoline. That would be .4 gallons assuming the published 50 mpg for the vehicle running with the generator on. At $3. per gallon that would be $1.20 worth of gasoline in one direction. If you charge at work, it’s the same thing going home. So you’ve driven 100 miles a day on .8 gallons of gasoline. Which is 125 miles per gallon equivalent. Cool!
Notice I didn’t provide a cost per mile driven. At 50 miles per gallon with $3./gal gasoline, it’s only 6 cents a mile WHILE THE GENERATOR IS RUNNING. If the car had no batteries, 50 miles per gallon is better than anything on the market. And better than most parallel hybrid vehicles. No transmission system, no drive shaft, no differential, substantially lower vehicle weight, all of which spells reliable.
The real point of the Volt, as a “true” hybrid electric, is it’s simplicity and reliability. As battery technology continues to improve, we will surely see pure “plug in” electric cars, but the Volt is a great solution that we can use right away until that day comes.
The Volt may be a new page in the history of the automobile, transposed and modernized from the electric vehicle industry of 100 years ago. It still has the power to transform the car making business. And right now, that’s also something we all need.