Driving the Toyota Prius Plug-in Hybrid

2010-09-29

The Prius coasted to a stop, out of gas. I was miles from a gas station. Now what? But I was in a different sort of Prius " a modified plug-in version, which Toyota is testing prior to an expected version for mass production in 2012. Luckily for me, then, a light plug was close by. I unrolled the long charging cable that comes with the car and tethered the car to 110-volt household current. And so began a three-hour charging procedure, but in due time, I was on my way again, running solely on electricity. I had a cushion of 14 miles of all-electric range, at speeds up to 62 miles per hour, with which to find a gas station. In a week’s worth of driving the experimental plug-in Prius, this was but one of several answers I found to the question: What good is a plug-in hybrid with a range of 14 miles in E.V. mode? The 14-mile all-electric range can be almost worthless in a road-trip car (as I found on a 700-mile trip from Los Angeles to San Francisco and back). But in a commuting situation, driven resourcefully, it can be a gas-free solution to tailpipe pollution. A garden-variety 2010 Prius hybrid can travel about a mile on its battery pack alone, before the gas engine kicks in, to power the car and recharge the battery pack. In this experimental plug-in version, two additional battery packs have been installed; each has an all-electric range of seven miles, hence the 14 total. The Chevrolet Volt, by comparison, can run " General Motors claims " up to 40 miles on electric power alone. Then a small gas engine starts up to provide enough charge to power the motor. That extends the Volt’s range. The plug-in Prius, meanwhile, operates differently. Once its additional battery packs run out of juice, the car becomes a regular Prius, operating on the standard Prius hybrid system. So what clever ways can we devise to maximize the 14-mile range? I asked two Toyota employees who have spent significant time testing the car. Dave Lee, a Toyota spokesman who lives 70 miles from work, told me the 14-mile boost of all-electric operation bumped up his fuel economy by nearly 10 percent. “I get about five extra miles per gallon, on average, than a regular Prius,” he said. A 2010 model Prius is rated at 50 m.p.g. in combined city-highway driving. Jana Hartline, a Toyota spokeswoman, lives seven miles from the office. She said, “I wanted to see if, by driving it carefully, I could go back and forth to work all week, without using any gas. I did it, but I didn’t have much of a social life that week.” She might have been able to have a little more freedom " and twice the range " if she had been able to charge it up at work. In my testing of it, with practice, I became proficient in tooling around town, driving in a normal manner, solely on electric power. But the penalty for 15 minutes or so of all-electric power was three hours of downtime to recharge it. That regimen extrapolated out to about 45 minutes a day of usable all-electric capability in exchange for nine hours hooked to the charger. (At 11 cents a kilowatt/hour, it cost about a dollar a day for the electricity used.) It sounds like more of an inconvenience than it was. I felt like with more practice, and better planning, I could have become an even more economical operator of this vehicle. It will be interesting to see how development advances on the plug-in Prius. Toyota won’t say which way its development is going, but acknowledges it is being very conservative in how much it asks of the lithium-ion batery. By: Jerry Garrett