Taking it Higher on Electric Avenue; How plugged in do you need to be?(NEWS)

Byline: KEVIN A. WILSON

Most of us know by now that a plug-in hybrid is a car with a hybrid drivetrain that can have its batteries recharged from the power grid. It's turning out, though, that such cars may come in more flavors than Starbucks has syrups.

Case in point: We drove a prototype version of the plug-in Prius, or PHEV, that Toyota will offer corporate and fleet customers starting in late 2009. Our experience was a short tour of downtown Portland, Ore., and for the most part, it was what you'd expect: It drove just like a Prius, but one that runs less often on its engine, more often (and at somewhat higher speeds) in pure electric mode.

More striking is the way this PHEV (plug-in hybrid electric vehicle) operates distinct from what we are hearing about the Chevrolet Volt that General Motors will offer in late 2010. Toyota's approach is to start with a Prius and add plug-in rechargability. So the car retains the firm's hybrid-synergy drive, using what Toyota calls a series/parallel arrangement between the gas engine and electric motor.

In the PHEV version, there's a button (in the prototype, it was on the dash to the left of the steering column) labeled "EV mode that lets the driver choose to run the car only on electricity. If you've recharged the batteries by plugging in to the electric grid and then select this mode, the prototype will deliver six or seven miles of pure electric driving, burning no gas. The target for the production model is 10 miles of such range, enough for a lot of the trips many drivers make.

After thator if you demand more performance in the short term than the small motor or the battery-pack state of charge can offerthe engine kicks in. As with any Prius, the engine drives the wheels through the transmission when you need more power or range.

During our drive, when we'd been moving around in pure EV mode for several blocks, we wanted to get out from behind a diesel city bus as we climbed one of the many bridges over the Willamette River. Booting the accelerator for an uphill surge from less than 25 mph to more than 40, we saw a dashboard gauge indicating that we were demanding more energy than was available from the batteries. The engine kicked in briefly until we let up on the pedal, even though we selected EV mode. After the acceleration, the car almost immediately returned to pure EV mode.