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Toyota introduces 2012 Prius Plug-in Hybrid

2012 Prius Plug-in hybrid. Click to enlarge.

Toyota introduced the production Prius Plug-in Hybrid at the Green Drive Expo in Richmond, CA, as the newest member of the expanding Prius Family. With a starting base price of $32,000 (before rebates), the production Prius Plug-in features a 4.4 kWh Li-ion pack enabling an electric range of up to 15 miles (24 km) at speeds of up to 62 mph (100 km/h), according to Toyota. (The advanced grade plug-in Prius carries a base price of $39,525.)

With seating for five, the 2012 Prius Plug-in hybrid is expected to achieve a manufacturer-estimated 87 mpge (miles per gallon equivalent) in combined driving and 49 mpg in hybrid mode, or 2.7 L/100km equivalent and 4.8 L/100km, respectively. The production plug-in hybrid has a number of key changes from the 125 prototype demo units that were deployed in the field for testing and customer feedback. Toyota applied experience from that test phase, along with input from participants, to finalize engineering and improve features for the production model. Changes include:

  • Completely new battery design. Toyota’s goal was to reduce the cost, weight and volume of the pack from the NiMH system used earlier. The Li-ion pack is almost half the weight of the earlier pack, and so much more compact that the dimensions of the plug-in Prius are the same as those of the iconic liftback—i.e., there is no cargo penalty for plug-in capability.

    Although the gross energy capacity of the pack is reduced (4.4 kWh), the EV range is increased. At a media preview of the introduction Toyota declined to be more specific as to the enabling mechanisms, citing some final issues that needed to be worked through by the battery supplier.

  • EV mode is now user-selectable. The demo units defaulted to EV mode.

  • Maximum EV speed is up to 62 mph.

  • Maximum electric range is 15 miles

  • A charge timer allows you to set charge start and finish time. (According to Toyota, one of the things they discovered during the demo program was that the battery packs responded better if they were allowed to rest prior to recharging.)

  • The charge port is moved from the front driver-side fender to the rear passenger-side fender, while the charger is now moved back with the smaller battery pack. The result is a shorter distance from the charge port to the charger/battery, reducing weight.

  • The charging cable is redesigned to be more flexible and lighter.

  • Entune with plug-in hybrid applications.

  • Other cosmetic and convenience features.

The 2012 Prius Plug-in Hybrid retains the Hybrid Synergy Drive of the standard Prius model and will seamlessly switch into hybrid operation at a pre-determined state of battery charge. The hybrid system includes the 1.8-liter engine, third-generation hybrid transaxle, and power control unit (PCU), now supplemented by the new Li-ion battery and on-board charging system. Net hybrid system output is 134 hp, and the plug-in achieves a California SULEV (with Enhanced AT-PZEV) rating, or Tier 2 Bin 3 Federal.

Engine. The 2ZR-FXE 1.8-liter DOHC 16-valve VVT-i engine develops 98 hp (732 kW) @ 5200 rpm, and 105 lb-ft (142 N·m) @ 4000 rpm. Key features of the engine include the Atkinson combustion cycle; Electronic Throttle Control System with intelligence (ETCS-i); exhaust heat recirculation to heat engine coolant to reduce time to reach operating temperature (shortening the time until the gasoline engine can stop); and cooled exhaust gas recirculation to reduce cooling loss and pumping loss. With lower exhaust heat, heat efficiency was enhanced, and consequently, fuel efficiency was enhanced as well.

The engine also uses an electrically driven air conditioning compressor and water pump to reduce mechanical losses. The electrically driven water pump allows coolant flow rate to be controlled with greater precision based on vehicle conditions for better fuel efficiency. Cabin heating and air conditioning can also continue operating with the engine stopped.

Hybrid transaxle. MG1 (motor-generator 1) is an air-cooled permanent magnet motor rated at 56 hp (42 kW). MG2 is an air-cooled permanent magnet motor rated at 80 hp (60 kW), and develops 153 lb-ft (207 N·m) of torque. MG2 runs at 13500 rpm maximum.

The multifunction gear combines a power split planetary gear set ring with a speed reduction planetary gear set ring, and incorporates parking gear and counter drive gear. The differential ratio is 3.267.

The power split planetary gear set comprises two sets of planetary gears; there are no clutches, bands, valves or hydraulics. The sun gear is connected to MG1 (acting as the generator); the planet carrier is connected directly to the engine, and the ring gear is connected to the counter gear.

The speed reduction planetary gear set’s sun gear is connected to MG2 (acting as the motor), the carrier is grounded and the ring gear is connected to the counter gear.

Power Control Unit. The PCU features a compact inverter design with direct cooling of IGBT transistors, and converts DC to 3-phase AC to drive MG1 and MG2. Controlled by the hybrid ECU, the PCU boost converter raises 201.6 VDC up to 650 volts DC. (The MG ECU is packaged within the inverter assembly.)

Charger. The on-board charging system accommodates single pulse DC 110/220 volt input, and is compliant to SAE J1772 standards. Maximum input current is 12A, and maximum output is 2 kW. Charging time at 110V is about 3 hours; charging at 220V cuts that in half.

Even with the addition of the new onboard battery charging system and larger 176-lb Li-ion battery pack, the 2012 Prius Plug-in Hybrid weighs just 123 lbs more than the standard Prius Liftback, due to weight-savings techniques applied elsewhere. As a result, driving performance for the 2012 Prius Plug-in Hybrid will be similar to the standard Prius.

Leviton, an approved provider of Level 2 (240V) home charging stations, has developed a residential program exclusively tailored for Prius Plug-in customers. The program will include a one-stop solution for home charging stations, installation services for 120V and 240V applications, and dedicated support for Toyota customers. The program will also offer Level 2 (240V) 16-amp and 30-amp home charging stations designed exclusively for the Prius Plug-in (UL-certified). Pricing starts at $999 for Level 2 (240V). Prius Plug-in customers will be able take advantage of Leviton’s special pricing starting early October.

Driving modes. The Prius Plug-in offers a user-selectable EV mode and two hybrid modes: Eco and Power. In EV mode, the hybrid ECU operates the vehicle using only MG2 if required conditions—such as sufficient battery state of charge and vehicle speed within ECV mode range—are satisfied.

Eco mode maximizes fuel savings across all driving conditions. It modifies or smoothes out the electronic throttle control program to reduce throttle response (throttle opening reduced to a maximum of 11.6%) and modifies air conditioning operation. As an ancillary benefit, it improves performance in low-traction conditions such as ice and snow because the reduced output helps to minimize wheel slippage. EPA label calculations do not include Eco mode.

Power mode increases throttle response in the middle range more than normal.

Displays and information. New multi-information display additions have been included in the Prius Plug-in. A new EV Drive Ratio display records the ratio of driving distance covered by EV power, and the Hybrid System Indicator shows possible EV driving range when in EV mode. An Eco Savings Record screen, new to both the 2012 updated Prius and the Prius Plug-in, allows drivers to measure their savings over a customizable pre-set comparison vehicle. The pre-set areas include fuel cost for a gallon of gas and miles-per-gallon average.

In addition to offering Entune, Toyota’s new multimedia system, available smartphone applications developed for the Prius Plug-in Hybrid include Charge Management, Remote Air Conditioning System, Charging Station Map, Vehicle Finder and Eco Dashboard.

Packaging and weight optimization. A key goal for development of the Prius Plug-in was to deliver the optimal balance of performance, range, economy, packaging and affordable price. The new model delivers extended EV range without sacrificing roominess for passengers or for luggage.

The compact Li-ion battery pack is installed under the rear luggage area. Width, height and length of the luggage space remain the same as the standard Prius. There is no reduction in rear seat passenger room from the standard Prius model, with seating for three and 36.0 inches of legroom that is on par with midsize sedans. Significantly, the biggest change in packaging from the Prius Plug-in Hybrid test-fleet model is the smaller, more efficient battery pack in the production model. The new battery pack is approximately one-half the weight of the demonstration-phase vehicle, yet provides about 15% more range.

The 2012 Toyota Prius Plug-in has a weight of 3,165 lbs (1,436 kg) versus 3,042 lbs (1,380 kg) for the standard Prius and 3,373 lbs (1,530 kg) for the Plug-in test-fleet model. Suspension tuning has been altered in accordance with the change in weight distribution from the standard Prius model.

The Prius Plug-in reduced vehicle weight in other areas as well. In place of a spare tire, the Prius Plug-in carries a tire-sealing kit and inflator. The trunk floor panel features a reinforced honeycomb design and is about half the weight of the standard model’s floor panel, while the charging cable stores in a compartment at the rear edge of the trunk floor. As on the standard Prius model, weight was saved through use of aluminum in the hood, rear hatch, front stabilizer bar and brake calipers and by using super high-tensile strength steel in the inner rocker panel, center pillar and roof reinforcement.

Externally, the Prius Plug-in inherits the standard model’s low coefficient of drag at 0.25 Cd. The current Prius had received more wind tunnel hours of testing than any other Toyota in history.

The new Prius Plug-in will be offered in two trim levels, standard and Advanced. The standard trim level provides all of the features of the standard Prius Two grade, plus some features from the upscale Prius Three and Prius Four grades. The Prius Plug-in Hybrid also makes standard a new touch-screen Display Audio and navigation system with rear backup camera and Toyota’s new Entune multimedia services.

Toyota’s 36-month/36,000 mile basic new-vehicle warranty applies to all components other than normal wear and maintenance items. Additional 60-month warranties cover the powertrain for 60,000 miles and against corrosion with no mileage limitation. The hybrid-related components, including the HV battery, battery control module, hybrid control module and inverter with converter, and the battery-charging system and cable/connector, are covered for eight years/100,000 miles (10 years/150,000 miles for CARB states).

The Prius Plug-in Hybrid will also come standard with Toyota Care, a complimentary plan covering normal factory-scheduled maintenance and 24-hour roadside assistance for three years or 25,000 miles, whichever comes first.

The Prius Plug-in Hybrid will be on sale in 14 launch states beginning this October through Toyota’s Online Order System at www.toyota.com. Vehicle deliveries begin in Spring 2012. The launch states include California, Oregon, Washington, Arizona, Maine, Massachusetts, Vermont, New Hampshire, Rhode Island, Connecticut, New York, New Jersey, Maryland, and Virginia. A national rollout is planned for 2013.



@ ai_vin | September 18, 2011 at 02:06 PM

Thanks, 2015 is far from now unfortunatelly... What will i'll do till then.

Henry Gibson

They could have stayed with their original battery and added a ZEBRA or Durathon battery made to fit in the space for more miles and a very long life and easier cooling. If the ZEBRA battery became temporarily frozen because the car was not used or plugged in for several days, the car could revert to original hybrid mode. You might even get a cheap lead battery to fit into the space used and get 15 miles. Prius could have used a flywheel in its original Prius at lower costs and got the same advantages. ..HG..



Yes, they had to somewhere find a compromise between price, usability and range. Remember it was also a question of limited volume: they wanted to fit the battery in the car without sacrificing luggage space.

I don't think we'll have to wait until 2015 for the next gen plug-in Prius. The current model Prius was introduced late 2008. The gen IV Prius will probably be introduced in 2013, with a plug-in version available at introduction. And yes, it is to be expected that that plug-in version will have a longer range.



Try here.

B.t.w if you think that we battery enthousiasts killed the fuel cell car.... I wish it were true.


Oh God! not that HHO scam again?
The only thing a HHO system can do for sure is speed up the flame front in the combustion chamber. Now if your car is poorly designed or old and leaves a lot of the fuel mixture unburnt a faster flame front could solve the problem by reaching it before the exhaust valves open and give you better MPG, but new/modern cars leave next to no unburnt fuel after combustion so they would see no improvement with this system.

You want a hydrogen powered car? try this; http://www.switch2hydrogen.com/h2.htm


@ Anne | September 18, 2011 at 11:08 PM

Don't confuse homemade, un-calibrated, amator hho kits and industrial, calibrated, non-polluting and adapted fuelcells. Hydrogen can be produced in unlimited quantities for free and without pollution when fabricating and using it. I usually don't listen mad scientist like you that just want to destroy the biosphere cuz the're affraid of getting bacteria related deasease.


BTW even if the physics of HHO didn't show it to be a scam the ways its promoters sell it should; http://www.youtube.com/watch?v=LSnSxAMjXq8

Chad Snyder

I think Toyota picked almost exactly the perfect EV range.

According to the latest IBM transportation study, the average 1 way commute is about 12 miles. So shouldn't plug-in architecture be built around this reality to start? Besides, workplaces can better amortize plug-in/smart grid investments.

Likewise, according to a recent Cost of Ownership study cited here on GCC, the ideal EV range for plug-in cost-effectiveness through 2030 will probably be about 17 miles, and cost-effectiveness will be the key driver of plug-in adoption, not EV range.

That puts Toyota in the sweet spot.

Ultimately, mainstreaming requires cost-effectiveness, ease of refueling, and reliability. It seems to me the Prius plug-in nailed those 3 requirements much better than any other automaker thus far.


Anne...hope that your are correct on all counts. The generation IV Prius PHEV could have 1 to 4 (5 Kwh) higher energy density modules that buyers could buy as options to get close to 15, 30, 45 or 60 miles e-range, to best meet individual requirements. That would make too much sense to happen?


"I think Toyota picked almost exactly the perfect EV range."

So Chad, you dont think its a bug, its actually a feature?.. the amazing part is how close they came to cost of a Volt, lets see how Volt sales do now that the factories are cranking them out.

Roger Pham

Thanks, Chad, for the info on the average 1-way commuting distance of 12 miles. Plug-in charging at work is the key for meaningful mass adaptation of PHEV.
I've always voiced my concern here in GCC regarding the large size of the battery pack of the Volt and how that would add to extra weight, cost, and lessen the much valued internal space. I've suggested many times that the battery pack of the Volt should be no more than 8kWh, in order to bring down the cost of the car.



From what I understand, the cycle life of a battery is shorter if you go too deep into discharge. So maybe having a 40 mile range even if you're only going 12 is a good idea.


RP...buyers should have the choice of battery size they really need. About four (4) optional battery modules would be enough to satisfy most requirements. That should not be a major challenge to integrate in most PHEVs and BEVs. One could start with a single module and add more at a latter date.

Roger Pham

@ai vin,
newer Lithium chemistry allows for deeper depth of discharge and still maintain high cycle life. Toyota has done all these tests, so the 14-mi range is after consideration of cycle life maximization.

When this battery will be used up, the second one will cost probably half as much...

Luggage space is of the essence, and is the limiting factor. The Prius v should give more space for a larger battery pack.



"Luggage spaces if of the essence" ? I thought time was of the essence. Or maybe time is money, and by the transitive property, money is of the essence, which gets back to affordable batteries in affordable cars.

I'd love to commute in all-electric mode, but if I'm recharging every day at work and every night at home, recharging had better be really easy. Right now I'm imagining a 3-prong extension cord dangling in the parking lot at my office.


Treehugger prefers "20 miles as the minimum EV range to qualify as a PHEV," as "the 4.4KWh battery is not powerful enough," and "unless there are charge stations everywhere for trips, it is more a toy than a milestone."

On the contrary, a 10-20 mile driving range on a PHEV battery pack is "ideal" for many reasons and especially to reduce our need to drive. The Chevy Volt's 40-mile EV range and most BEV's 100-mile range offer less incentive to reduce routine driving. Maintaining our idiotically wasteful driving habits with a longer EV range only leads to more driving. Corporate America has no interest in killing their sacred cow.

We drive too much, too far, for too many purposes at too high a cost and impact. Furthermore, the PHEV's smaller battery pack is a better match with rooftop photovoltiac panels and can reach more than twice the number of households which may more closely monitor and conserve all energy consumption.

Hydrogen fuel cell vehicles have the same disadvantages of the BEV plus its own numerous and specific disadvantages which psuedo-enviromentalists haven't given the least thought.

Bob Wilson

The plug-in Prius is well positioned for an advanced control law that uses the EV mode for acceleration. We have a 2003 Prius and the very limited, ~45 seconds, of engine start, EV, allows the car to reach 35-40 mph with ending MPG rates of 50-60 MPG. Our 2010 Prius has nearly four times the early EV mode, ~200 seconds. Once at cruise speed, the rest of the fuel consumption is spread over a longer distance than the acceleration zone.

Acceleration use of EV keeps the engine in a fuel efficient mode while the vehicle kinetic energy increases. Then at speed, the gas engine produces power very efficiently and puts in a charge. Any regenerative braking puts a respectable charge back into the traction battery. This is not theory but practice with our 2003 and 2010 Prius.

If the plug-in can switch on the fly between EV and ECO mode, early adopters will have an excellent tool to extend the Prius energy efficiency range. Essentially, vehicle acceleration, the least efficient fuel consumption mode, can be avoided by using EV to accelerate and ECO to cruise.

Bob Wilson, Huntsville, AL

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