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Monday December 22, 2008
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Ford says its new Ford Fusion Hybrid gets at least 39 mpg city. AutoBlog Green says it got 43 mpg. Some colleagues at the Ford Fusion introduction in December in Los Angeles also got in the mid-40s and a couple topped 45 mpg. So why did I wind up with mileage, on the same route, in the low- to mid-30s? It's a combination of driver skill, driver courtesy to other cars, road conditions, and vehicle condition. Here's why all the mpg numbers, anything from 30 mpg to 50 mpg, can be considered legitimate:
Driver skill. Some drivers are more attentive to the car and the needs of hybrid driving. Some want to maximize mileage - the hyper-milers - possibly to the exclusion of all else. Drivers with a gentle foot will get better mileage. To maximize hybrid economy, you start off sedately and apply the throttle gently to use only the electric motor for as long as possible.
Courtesy. Some of what you do to stretch fuel economy stands in opposition to what you do to be a considerate driver. Drive away from a traffic signal with the intention of keeping the car on battery power for as long as possible, and traffic builds up behind you and annoys the drivers stacked up. I'm surprised you don't see more Toyota Prius rear windows shattered by gunfire. (The hotheaded road rage vigilante takes on the self-righteous green twit.) It may also be that when hybrid drivers set a slow pace, they limit the ability of highways to carry motorists (vehicles per lane mile per hour).
Road conditions. Run the same test on a Sunday morning, a weekday at midday, and a weekday at rush hour, and you'll be doing increasingly more starting, stopping, and standing. My stint through Los Angeles streets included an hour of rush hour traffic.
Vehicle condition. On a short economy run of an hour or two - the measured portion of my run - the battery's state of charge comes into play. When I started my leg, the storage battery was near its minimum charge, meaning that for the first several miles, we were running mostly on gasoline power while the battery built up its charge. Over the course of a day it all averages out.
In my case, I made it a point to accelerate from stoplights keeping in mind that it's not neighborly to hold up cars behind me. At the same time, I did ride the brake lightly when decelerating, which in a Fusion invokes regenerative braking, rather than hard braking (you invoke the physical brakes) or coasting (no regeneration). And I had the air conditioner on. It was December, but this was also a sunny day in Los Angeles. And in heavy traffic, I found it difficult to keep shifting from the road to the Eco Gauge and back.
Ford engineers say anyone with a bit of training (and conscientious application of the training) can get city mileage in the low 40s from the Fusion Hybrid. Possibly so. But it's dangerous to extrapolate that every car traveling U.S. roads could get 40 mpg or better if we had more hybrids. It also calls for a change in driving habits. Slower acceleration, maybe? But not use your air conditioner in the summer? Unlikely. And it also calls for something other than gasoline engines on the highway. If you want 40 mpg in a mid-size car at highway speeds as well as in urban areas, what you need is the diesel hybrid. That may be the technology ride of the future.
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