We just got back from test-driving the 2012 Toyota Prius V (the new, bigger Prius). You'll be able to read our first impressions on it later this week, but in the meantime, we picked up some news related to the forthcoming 2012 Toyota Prius PHV, the plug-in hybrid version that we recently drove in prototype trim. As we noted in that firsthand review, the plug-in Prius we drove is part of a test fleet. Toyota's collecting all kinds of data and feedback that will help it shape the final production car, which we learned will be unveiled to the public this September at an event in California. Look for it in showrooms sometime early next year. In talking to the Toyota folks at today's Prius V event, we also learned of two crucial changes being made that should improve the Prius PHV's all-around usability and will likely tweak its fuel efficiency for the better.
The different Prius driving programs
First, a little background. The regular Toyota Prius has four driving modes: Eco, Power, EV (Electric Vehicle), and Normal. The first three are driver-selectable via console-mounted buttons; Normal is the default mode every time you fire up the car. One of the things missing from the Prius Plug-In Hybrid prototypes is an EV mode selector. It only has buttons for Power and Eco Modes. That's because on the Prius PHV, any time you start up with enough charge in the battery, the car defaults to EV mode. It will run as an EV until that level of charge is exhausted, at which point the battery and hybrid powertrain perform like any standard Prius. This is good and bad: Good if you jump in the plug-in and do a lot of local driving, where you get the most out of EV mode, bad if you happen to jump on the highway, where the EV assistance at higher speeds eats up your EV-mode charge quickly.
Plug-In Prius getting dedicated EV mode button
This brings us to the first significant change we'll see on the production 2012 Toyota Prius Plug-In Hybrid: a selectable EV mode. This is a big deal. Now, if, for example, you know you're going to get in the car and get on the highway, you'll be able to turn off EV mode with a button and preserve your valuable electric-only range for when you get back into local driving.
Full battery regeneration for the production Prius PHV
Part two of the story is that the production plug-in's battery regeneration capabilities will let you put charge back into the electric-only range. The current Prius PHV prototypes only allow battery regeneration to the same degree as a regular, non-plug-in Prius. Once you run your EV-mode range down to zero, braking, going downhill, etc. will regenerate power as in a standard Prius, but the system can't build your EV-only range back up. For that, you need to plug the car in (a full recharge takes three hours on a standard 110V household circuit and gives you 13 miles or so of EV range).
Plugging in will still obviously be the fastest way to replenish the battery on the production Prius PHV, but its drivers will get a bonus: the car's regeneration capabilities will allow them to put range back into the EV mode. So, if you're driving along and get some nice downhill sections where you can coast and/or leverage the engine braking feature of the transmission, you'll actually be able to regenerate power to build up or extend your EV range beyond the nominal amount you get when the battery is discharged to the "regular Prius" level. The prototypes can't do that, so this is significant.
More changes in store?
Those aren't apparently the only improvements on tap for the 2012 Toyota Prius Plug-In Hybrid, but we'll have to wait and see what else Toyota has up its sleeve along with the rest of you. The news we did confirm is exciting, however, considering how good the plug -in prototype is to begin with.
If you missed it the first time around, check out our hands-on review of the Prius PHV prototype, and check back Friday to read our first take on the new 2012 Toyota Prius V crossover/wagon.