Going for real and simulated drives to find your personal best MPG

Got a minute? Go to My Demo Drive for a mini-education on how much gas you can save by driving a mid-size gas-electric hybrid compared to a similar-size conventional car, with and without "start-stop." A fuel-saving system that stops the engine at rest and restarts it when the brake is released, start-stop is increasingly popular in Europe but still rare in North America largely because the EPA doesn't give automakers fuel economy ratings credit for it.

What you'll find at that site is Johnson Controls' interactive "Demo Drive" advanced vehicle technology education tool. Click your side of the Atlantic (U.S. or Europe), then select your driving style from a half-dozen choices ranging from "Motorway Maven" to "Delivery Driver." I chose "Countryside Commuter," which would take me mostly on suburban roads and highways at speeds up to 70 mph. I also entered my local gas price at (gulp!) $4.19.

Then I hit the simulated road on a 15.27-mile commute from simulated home to simulated work. Unrealistically, I clicked through it in a few seconds, then compared my fuel economies and costs for the trip: 24.1 mpg and $2.64 in the base car; 25.6 mpg, $2.51 in the same car with start-stop; 34.2 mpg and $1.89 in a similar-size hybrid.

The results also estimate annual fuel-cost savings based on 12,000 miles of driving – mine were $129 with start-stop and a substantial $619 for the hybrid vs. the conventional car – and "pay-off" time for the more expensive technologies: a discouraging 6.2 and 8.0 years, respectively. You can play with different driving styles/routes and share and discuss your findings on a dedicated Facebook page. What you can't do (yet) is experiment with different vehicle sizes or technologies (BEVs, EREVs). Continue reading...

"We built Demo Drive so that consumers can see for themselves how the various types of vehicle technologies can positively impact their lives," says Mary Ann Wright, global vice president for technology and innovation at Johnson Controls Power Solutions. "It allows people to pick a driving style that is closest to their own and see the cost and emissions benefits of two of the most realistic and globally available technologies – hybrid and start-stop." Not coincidentally, JC is the world's leading supplier of start-stop batteries and a leading global supplier of lithium-ion advanced battery systems for hybrids and EVs.

Way better than a simulation, though, is real-life experience. I was recently privileged to enjoy the use of a Chevrolet Volt for a week and a Nissan Leaf for a couple days.

I picked up the fully-charged Volt on my way to a Detroit-area press event – where Chevy unveiled its fine-looking 2013 Malibu (which will be available with start-stop as an element of GM's eAssist mild-hybrid system). It showed 33 miles EV and 305 miles total range (following a 1.7-mile check ride) when I departed. I drove 34 miles to the event and arrived with four miles of eRange remaining. Afterwards, I drove it home, 84.6 miles, mostly on freeways.

As I slid the Volt into my garage, it was showing 231 miles total remaining (gasoline) range. I had used just 2.3 gallons of gas for my 118.6-mile trip and averaged 51.2 mpg. I set it for "delayed" charge (to finish by 5:30 am) on 120V house current and plugged it in.

Next morning, it offered 36 miles eRange based on my previous day's rate of usage. I drove it 32.5 miles around town before eRange went to zero and the range-extender engine started (almost imperceptibly) just a block from home. Gas burned on that 33-mile trip: 0.03 gal. Total average fuel economy (since picking it up): 64.4 mpg. It offered a choice of "immediate" charging (100 percent by 10:15 pm), or "delayed" to finish at 5:30 am. I chose immediate, but then interrupted the charge process to take my wife to dinner. Predicted eRange on departure: 23 miles. When we returned: 12 miles. Fuel usage: zero.

My last night with the Volt, I took it out to see how quickly I could deplete the battery. I reset the "B" trip odometer, dialed up "Sport" driving mode and "Comfort" heating (ambient temperature was a chilly 39F), then drove it as hard and fast as I safely could, accelerating full-voltage every chance I got. I departed at 34 miles predicted eRange and 7.2 miles later was down to 19. I was running 79 mph on a freeway when it went to zero at 20.5 miles, and the coin-stack gauge rotated around to show 221 miles of gasoline range remaining.

I headed home and arrived at 29.7 trip miles with a predicted 210 miles left in the gas tank. Amazingly, I had used just 0.3 gal. over those last 9.2 gas-only miles and averaged 99.0 mpg for my near-30-mile wild ride.

Total ("A" trip odometer) miles since picking up the Volt: 191.2. Total gas burned: 2.6 gal. Total average (EV and gas) "fuel" economy: 72.3 mpg. The read-out also provided total fuel economy over the short but hard 2058-mile life of that press-test Volt: a very respectable 49.2 mpg. The next morning, its predicted EV range was 32 miles, and 212 were left in the gas tank, for a total 244. I really hated to see it go.

My comparatively brief Leaf experience was very different, though mostly good. For starters, they had to truck it to my house. Even if it could have made the (mostly freeway) 90-mile trip, it would have arrived on EV "fumes" and taken one day (of my allotted two) to recharge on 120V. So they delivered it fully charged showing 96 miles of eRange.

I set out driving conservatively on a local errand run, switched on the A/C (which instantly dropped eRange to 84 miles) on an 84F afternoon and made several stops. At 5.0 miles, I switched to ECO mode, and eRange bumped up eight miles. The 11.5-mile trip left me with 83 miles on ECO, or 75 in normal mode.

Without recharging, I took it out again after dark for an aggressive night drive (in ECO mode with sound system, lights and A/C on). I drove it hard and fast (up to 65 mph), but not as far as the Volt, since I had no range extender to get me home should I run short of volts. This 13.1-mile drive left 54 miles eRange on ECO (or 49 normal) with a projected charge time of eight hours on 120V (or three on 240V, not yet an option in my garage). I made a mental note to ask why the Leaf doesn't default to ECO mode and run that way all the time, unless the driver chooses to switch to less energy-efficient normal, instead of the other way round?

Observations: both cars are terrific, but I prefer extended to limited range despite its higher price (similar lease payment, though). The Leaf may be "greener," but the Volt is quicker, more agile and more fun to drive. The smart phone provided with the Volt proved of little use (I was under-trained to use it), but the online connection through OnStar was great. The Leaf's 120V charge cord is REALLY thick, and they recommend no extension cords for fear of burning one up, so high is the load.

I would have liked more Leaf time, but I was fortunate to have a conventionally-powered alternate choice for my 90-mile drive to the airport the day it was picked up.

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