Plug-in Prius: Work in Progress

By: Anthony Fontanelle

The Toyota Motor Corp. is intensifying its commitment in the production of hybrids and environment-friendly auto technology. The Japanese automaker's latest venture is the plug-in version of its iconic Prius.

Under high-load situations such as high-speed roads, Prius PHEV, the petrol engine will operate alike, leaving the car with the same aptitude to go faster and use freeways. Current converted Prius also operate in a high speed blended mode which can reduce but not eliminate petrol consumption on the freeway.

When driving in slower conditions or other light loads, the batteries will be used first in a charge-depleting mode, allowing moderate commutes at low speeds to be driven entirely on electricity. Once the batteries have been sufficiently discharged the car will automatically revert back to the charge-sustaining mode of the present Prius. Safe lithium-based batteries will be available, slashing all risk of run-away thermal conditions as seen in some laptop computer batteries.

Hybrids such as the present Prius use a conventional gasoline engine as their primary source of power. A tiny, battery-powered electric motor powers the car for very short distances at low speeds and offers extra power at higher speeds. Toyota Prius is the highest miles-per-gallon rating of any mass-produced car in the United States.

One of the lucky auto journalists invited by the manufacturer of to test drive the plug-in Prius is Martin Zimmerman of the Los Angeles Times.

Zimmerman writes: I had to go to Japan to do it, but I finally got my hands on a plug-in hybrid. So with the automotive media in town this week for the Tokyo Motor Show, Toyota perhaps decided it was opportune to demonstrate it has been spending time and money finding ways to replace the environmental disaster that is the internal combustion engine - and has the sheet metal to prove it. Which is how I came to be at a Toyota test track near the foot of Mt. Fuji, surrounded by engineers, interpreters, PR types and about half a dozen plug-in Priuses - cars that may have a lot to say about how we get around in the future.

According to Zimmerman, the plug-in hybrids were equipped with nickel-metal hydride battery packs about twice the size of the ones in the current-generation Prius. The reason is to simulate the extra power the automaker intends to get from lithium ion batteries. At present, the latter are the leading choice among automakers for providing the power needed to move plug-in hybrids appreciable distances on electricity alone.

"A second test drive in a different test car resulted in the kind of torque-y acceleration electric motors are known for, speeding smoothly and quickly up to 50 mph or so, at which point an extra dose of throttle caused the gas engine to kick in -- as expected. And this time, almost as soon as the pressure was eased on the gas pedal, the car went back into electric-only operation as it was supposed to," Zimmerman narrated.

"Truth be told, I think I was a bit spoiled by the hydrogen fuel-cell Toyota Highlander I tried out just before the Prius test runs. The mid-size sport utility vehicle, powered solely by an electric motor, displayed very un-SUV-like oomph as I pushed it past 50 mph. It was smooth as silk and brimming with torque," he concluded.

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