Toyota introduces 2012 Prius Plug-in Hybrid
17 September 2011
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| 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.

The compact Li-ion battery pack is installed under the rear luggage area.
So you DO lose storage area. The underfloor area, which was always good for quite a lot when stuffing the car for a vacation.
I couldn't get confirmation on this detail, but is the NiMH pack still there for normal hybrid operation? I read it was for the test-model.
As usual with Toyota, they have taken the safe route. They have a reputation of reliability to defend. Therefore the pack has an energy density of only 55 Wh/kg. It is intended to be trouble-free and last the life of the car.
Posted by: Arne | 17 September 2011 at 05:07 AM
There is a press release from Toyota where there is more info about the PHEV Prius see
http://www.toyotagb-press.co.uk/protected/vehicles/releases/2011/65288toy_Toyota_Prius.htm
It shows the new battery pack weights 80 kg and contains 4.4kWh in comparison to the standard Prius battery that weights 42kg and contains 1.3kWh. In other words, at the pack level the energy density of the standard Prius is 31Wh/kg (=1300/42) and for the new PHEV Prius it is 55 Wh/kg (=4400/80). So clearly an improvement but still much below the energy density in the battery and control module in the Nissan Leaf of 80Wh/kg (=24000/300).
I guess the reason that Toyota has not been able to do better in energy density is that they use a very high power battery cell that is intended for standard hybrid applications and not really a dedicated PHEV application. For this reason I speculate that the current battery pack for the PHEV Prius will be short-term (less than 3 years). As soon as Toyota can obtain in volume a dedicated battery cell for fast charging battery EVs and PHEVs the current version of their battery will be replaced. That should also enable Toyota to lower the price and deliver a larger pack than the 4.4kWh that goes into the current Prius PHEV.
Priced at 32000 USD and with less acceleration, far less electric only range and less electric only top speed I do not think that the Volt or the Leaf has much to fear in terms of competition.
@ Anne the old NiMH pack is gone.
Posted by: Account Deleted | 17 September 2011 at 05:29 AM
"Priced at 32000 USD and with less acceleration, far less electric only range and less electric only top speed I do not think that the Volt or the Leaf has much to fear in terms of competition."
With a dozen year history, 3 million Prius sold, and the plug-in hyubrid being just part of a multi-model Prius line - the competition has a lot to fear.
Posted by: kelly | 17 September 2011 at 07:01 AM
Only a little more than double the battery capacity of the very first Prius (which was 1.9 kWh).
Posted by: clett | 17 September 2011 at 07:26 AM
OTOH, the sudden-acceleration scare isn't going to be forgotten for a while.
Posted by: Engineer-Poet | 17 September 2011 at 07:40 AM
@Kelly
Maybe I should elaborate a little. I think that the supply of cars with a plug currently is so low compared to the demand that almost any price and set of features will sell out. After all we will produce 70+ million cars globally in 2012 and less than 200,000 will have a plug. Another way to put it; globally there are now over one billion car owners and if just 1% of those cares about the environment and are willing to pay a premium for a car with a plug that is about 10 million willing consumers for less than 200,000 cars in 2012.
The Prius PHEV will sell all they can produce which may be up to 50,000 in its first year (Toyota have mentioned that number but has not been specific of whether they mean first launch year) but so will all other cars will a plug. Had Prius been able to price their PHEV for 28000 USD it might have meant trouble for the Volt priced at 41000 USD but still not for the Leaf as it is a very different beast.
Posted by: Account Deleted | 17 September 2011 at 07:56 AM
I did the math yesterday. After rebates the Volt is only $3,000 more than the plugin Prius in initial cost. I had been leaning towards the Prius but I'm not sure now. Considering most of my driving is highway driving at 70mph I don't know if my MPG would be that much over a regular Prius.
Posted by: twitter.com/siromega | 17 September 2011 at 08:35 AM
If a plugin hybrid is fully discharged driving out of KC, Mo will it be fully recharged during interstate speeds when it reaches Denver, Col. ten hours later?
Posted by: kelly | 17 September 2011 at 08:41 AM
Probably not, unless there is a "mountain mode" which I have not seen listed in the options. The idea is to turn battery power into motion and vice versa, not gasoline into battery power.
Posted by: Engineer-Poet | 17 September 2011 at 08:53 AM
It might be positive if the battery ~trickle charging on the interstate could then make electric economy available for city stop-n-go.
Since basic Hybrid Synergy Drive R&D and reliability were repaid before GM went SUV bankrupt, it's likely Toyota could drop a Prius plugin hybrid price well below US $30k, if it were to prove significantly to Toyota's advantage.
Posted by: kelly | 17 September 2011 at 09:22 AM
siromega the Prius qualifies for a $2500 fed rebate with the new 4.4kWh battery. In highway driving after the electric charge is gone the Volt gets about 37mpg and the Prius 49.
Posted by: sascatcher | 17 September 2011 at 09:33 AM
In our area, only HEVs/PHEVs/EVs with very large batteries (16+ Kwh) get the maximum subsidies ($8K to $10K). With only 4.4 Kwh the Prius PHEV would not qualify for much more than $2.5K. That was done to favor the Volt and Leaf. Whenever the Prius PHEV is produced locally, pressure will bare to get better subsidies. Otherwise, it would be to Toyota's benefit to increase the on-board battery closer to 16 Kwh. This may not come before 2015+ with next generation PHEV equipped with their new higher performance solid state batteries.
Posted by: HarveyD | 17 September 2011 at 10:10 AM
Does anyone know how the "normal" prius battery gets recharged while the "extra" battery for EV mode doesn't? Do they have two electrically separate batteries, or do they recharge the one primary battery just enough to make sure "regular" hybrid mode still works?
Posted by: TM | 17 September 2011 at 10:19 AM
@Anne,
No lost of luggage space in comparison with the Pr!us HEV.
The Lithium battery pack simply replaces the NiMh pack plus the spare tire.
$32,000 before rebate is a good deal for early adopters who do a lot of city driving. It gives a distinct status symbol at a lot less premium than a Lexus or any other luxury badge. For that, Toyota must have a large badge clearly show the PHEV status.
Posted by: Roger Pham | 17 September 2011 at 11:25 AM
I have a mixed feeling about this car, on one side it is good that we can get a PEHV for 30K$ on the other side 14miles EV is really short, I think that 20miles is really the minimum entry range to qualify as a PHEV. Or this car should be sold below 30K. It is more a car to give a flavor of the PHEV than really an extended range EV. The problem is that 4.4KWh battery is not powerful enough so as soon as you accelerate or pass the 60MPH the gas engine will kick out, breaking the EV only unique experience. Maybe if one day there is plug everywhere you can use this car on EV mode only for significant portion of your trips, but other than that it is more toy than really a milestone
Posted by: Treehugger | 17 September 2011 at 11:42 AM
Tree.... may be correct with the minimum e-range for PHEVs. Something like 20 miles should be the bare minimum and 40 miles would be better (minimum?) for people living in distanced suburban areas.
Toyota should look around for much better batteries, with much higher energy density (3x to 4x) to increase e-range from 15 to 45 or 60 miles. Such batteries already exist. Their partner Tesla could help?
Posted by: HarveyD | 17 September 2011 at 01:04 PM
Quote from the article '' the battery packs responded better if they were allowed to rest prior to recharging.) '' This is bad news for the folks advocating bev( battery electric vehicle ). They want to travel like gasoline cars or volt with public quick chargers installed everywhere, LOL. They rejected hydrogen these morons and now we learn that i was right.
Posted by: A D | 17 September 2011 at 01:59 PM
This more or less puts the "electric highway" problem to bed.
With a PHEv you have more or less unlimited range and quick gasoline refuelling.
I think any PHEv is a good thing, even one with a 14 mile range.
It is much better to have 3 PHEVs with 14 mile range than one with 42 mile range.
The trick is to program the system so it uses the battery so as to maximise the efficiency of the ICE - i.e. not run on EV for the first 14 miles and then run on ICE until it is recharged.
It should be possible to learn the owner's commute and then use the battery for the stop-start or low speed parts of it, leaving the ICE for the higher speed parts.
Posted by: mahonj | 17 September 2011 at 02:09 PM
I have mixed feeling about this car also, but mostly because more is always wanted (at the same price of course).
The EO range matters little except for the rebate.
Compared to the original Prius, 14 mi is enormous.
It is a great car but time has passed, competition (at less affordable prices) ups our expectations and appearance is a bit dated and "industrial".
But it is a very well engineered (with good compromises) car yet still appeals to the purist.
How close is it to being a good buy for someone who puts 15k Mi per year, 50/50 city freeway?
I don't know but, I hope it is closer.
Posted by: ToppaTom | 17 September 2011 at 02:13 PM
I'm a little surprised on the pleasant side. For a quite affordable price, I could do most of my driving on electric, particularly since my round trip commute is 7 miles. I have a refundable deposit down on a Volt. Hmmm.
Posted by: stephenboulet | 17 September 2011 at 05:45 PM
For someone with a 28-mile commute daily, this PHEV Prius can do half of it with electricity alone. This can reduce petroleum consumption by 1/2, giving a petroleum mpg of 100mpg.
For someone with access to an AC 110V socket at work, then the entire daily commute can be done with electricity alone! When enough people own PHEV's, more workplace will provide charging sockets for parking slots near the buildings, reserved for PHEV owners.
For those with over 28-mile daily commute, they perhaps should consider moving closer to the workplace. More daily driving means higher risk of traffic fatalities or injuries, more chance of getting stuck in traffics that can raise the risks of heart attacks and strokes, and less quality times in their lives.
Posted by: Roger Pham | 17 September 2011 at 07:33 PM
@HarveyD
You say: Toyota should look around for much better batteries, with much higher energy density (3x to 4x) to increase e-range from 15 to 45 or 60 miles. Such batteries already exist. Their partner Tesla could help?
I think Toyota deliberately stays on the safe side. They have a reputation for rock-solid reliability to protect, unlike Tesla, which can take more risks being the 'new kid on the block'. When you buy a Tesla, a new battery pack half-way through the life of the car is factored-in. The battery in a Tesla will degrade over the years, reducing the range as the car ages. Toyota has opted for a battery that will last the life of the car. And might even guarantee the electric range as the battery might have some spare capacity to compensate for aging.
Comparing to the Volt which has a 16 kWh battery weighing 197 kg. That is an energy density of 81 Wh/kg. Much higher. But when you look at the electric range per kg the Volt offers you 325 m per kg of battery, while the plug-in Prius manages 300. That is not much difference.
The stated 4.4 kWh battery capacity might also be the net capacity instead of the nominal capacity.
Posted by: Arne | 18 September 2011 at 05:28 AM
Good arguments Anne...but a similar quality, higher energy density, 10+ Kwh battery pack would meet more user requirements, but would cost $3K to $4K more. It may be available in the next generation Prius PHEV II by 2015 or so when battery price drop enough, ie. another 30% to 50%?
Posted by: HarveyD | 18 September 2011 at 10:41 AM
What Volt enthousiast are missing is that the Volt is built around the batty-pack, whereas the Prius has a small very accessible battery, just behind the back seats. If/when better batteries arive, and they most certainly will within the lifespan of the car, a simple battery upgrade during maintanance will transform this Prius from a very good plug-in-hybrid into a range extended EV, for the cost of a few thousand dollars.
I can't wait for aftermarket upgradekits for the Prius II, that will become available sooner or later at reasonable prices. This will allow the installed base of Prii to be coverted to range-extended EV's.
Posted by: ForeignObserver | 18 September 2011 at 01:38 PM
@AD
Toyota did not reject hydrogen. They've taken a serious look at it and decided batteries were a nearer term solution. They are still working on their FCEV though and you can expect it in the showrooms around 2015. However it looks like it will be a SUV. :^(
Posted by: ai_vin | 18 September 2011 at 02:06 PM