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Toyota Reveals Third-Generation Prius; 50 mpg

The 2010 Prius. Click to enlarge.

Toyota Motor Sales (TMS), USA, unveiled the third-generation Prius hybrid vehicle at the 2009 North American International Auto show. The new version of the world’s top-selling hybrid vehicle (more than one million sold in 44 countries) offers better mileage ratings and enhanced performance, as well as new design features.

The first-generation Prius, which was EPA rated at 41 mpg US combined city/highway, was replaced by the current model, which is EPA rated at 46 mpg US, combined. Using a combination of technologies, fuel efficiency was increased to an estimated 50 mpg US combined for the new Prius.

Hybrid components like the inverter, motor, and generator are now smaller and lighter. An exhaust heat recovery system, exhaust gas recirculation, and an electric water pump contribute to a more efficient hybrid system with a net horsepower rating of 134.

The battery module carries over from the tried-and-true technology from the current Prius. Engineers applied enhancements throughout the entire vehicle to achieve 50 miles-per-gallon, more consistent efficiency in real-world driving, and further reductions in CO2 emissions.

Electric power consumption has been reduced through the use of a more efficient air conditioning system and new, optional LED head lamps. Internal tests show that Prius’ zero-to-sixty acceleration time has dropped from the previous generation’s mid 10-second range to 9.8 seconds, making it comparable to that of an average mid-size sedan with a 2.4-liter engine. This is in response to customer expectations for better every-day performance. In short, the entire Prius package has been made more efficient from overall power consumption to output.

—Bob Carter, Toyota Division Group Vice President and General Manager

The new Prius also features what Toyota is calling a “Solar Moonroof”. A small array of photovoltaic cells automatically powers a ventilation system on hot days. The system allows fresh air to circulate into the vehicle, cooling down the cabin so that the air conditioning doesn’t have to work as hard, thereby conserving power.

Preliminary 2010 Prius Powertrain Specs
Engine 1.8L I-4 with VVT-i
Engine power [hp (kW)] 98 (73)
Torque [lb-ft (Nm)] 105 (142)
Motor power [hp (kW)] 80 (60)
Motor torque [lb-ft (Nm)] 153 (207)
Net power [hp (kW)] 134 (100)
Emission rating SULEV (w/ AT-PZEV)
Battery pack NiMH
Est. combined fuel economy 50 mpg US

A larger and more powerful 1.8-liter Atkinson-cycle, four-cylinder engine powers the new Prius. The larger engine helps improve highway mileage. By making more torque, the new engine can run at lower average rpm on the highway. When operating at lower rpm, the new engine uses less fuel. Mileage is especially improved in cold-start conditions and at higher speeds.

Use of an electric water pump and a new exhaust gas recirculation (EGR) system also contribute to the engine’s efficiency. The 1.8-liter Prius engine is the first Toyota power plant that requires no belts under the hood for better fuel economy and less potential maintenance.

The patented Hybrid Synergy Drive system in the 2010 Prius is 90% newly-developed with significant improvements over previous models:

  • The transaxle is lighter in weight and reduces torque losses by as much as 20% compared to the previous model.

  • The inverter, which converts direct current to alternating current, has a new direct cooling system to reduce size and weight.

  • Taken together, the inverter, motor and transaxle are smaller and 20% lighter.

  • A newly developed electronically controlled regenerative braking system has been adopted, with control logic optimized to enhance regeneration.

Under the hood of the 2010 Prius. Click to enlarge.

The new Prius will offer three alternative driving modes. EV-Drive Mode allows driving on battery power alone at low speeds for about a mile, if conditions permit. There is also a Power Mode, which increases sensitivity to throttle input for a sportier feel, and an Eco Mode, which helps the driver achieve the best mileage.

Dimensionally, the new Prius has the same wheelbase as the current generation. Overall length is slightly increased by 0.6 inches, in part by moving the front cowl forward. Designers preserved the triangle form of the current model, but made alterations to the overall profile, pillar position and angle. The overall height of the Prius is the same, but the roof profile is altered by moving the top of the roof 3.9 inches to the rear. This emphasizes the wedge shape, and also allows for enhanced rear headroom and improved aerodynamics.

The new Prius received more wind tunnel hours of testing than any other Toyota vehicle yet. By focusing on the shape of the body, underfloor, wheelhouse liner and shape of the wheels, the designers of the new Prius were able to reduce the coefficient of drag (Cd) value to 0.25, compared to 0.26 for the previous model. The airflow under the car was studied extensively. Engineers made changes to the shape of the fender liner, front surface of the underfloor, and added a fin at the rear floor cover to increase linear stability.

The next-generation Prius is built on a new platform, which enables improved handling stability, quieter operation, and collision safety. The suspension consists of front struts and a rear intermediate beam design, as before, but handling stability is advanced by improving the stabilizer layout, higher caster angle and tuning the bushing characteristics. Disc brakes are now used on all four corners, replacing the front disc/rear drum brakes in the current model.

Weight was saved through use of aluminum in the hood, rear hatch, front suspension axle and brake caliper and super high-tensile steel in the rocker inner, center pillar, and roof reinforcement. To meet customer expectations for everyday performance, zero-to-60 acceleration has been improved to 9.8 seconds, more than a second faster, in internal testing.

Better-performing sound insulation, working with improved vibration damping, has been installed in various locations to reduce road noise.

Toyota will use plant-derived, carbon-neutral plastics in the 2010 Prius. The newly-developed plastics, known as “ecological plastic,” will be used in the seat cushion foam, cowl side trim, inner and outer scuff plates, and deck trim cover. Ecological plastic emits less CO2 during a product lifecycle (from manufacturing to disposal) than plastic made solely from petroleum; it also helps reduce petroleum use.

Sales of the 2010 Prius will start simultaneously in both the US and Japan in late spring, followed shortly by Canada and other countries. Toyota forecasts first full calendar year sales in the US will be around 180,000 units.

We expect a large portion of this volume to come from current Prius owners. That’s because more than 90 percent say they will buy another Prius.

—Bob Carter



wow no belts! unbelieavble! belt free engine!!!

wow rear discs! WOW


It sounds like the engineers got a chance to do a lot of things they wanted to do before but couldn't because they were constrined by schedule.

I just hope they didn't make too many changes all at once - it increases the chances that you'll have manufacturing problems in the first year.

I wonder if they were able to supress the electrical whine that you get when the battery recharges on soft braking or during a coast. Maybe the improved sound insulation covers it up better. Anyway, you only hear it when the radio is off and there is no other traffic on the road nearby.

I would have liked the option to buy a bigger battery pack (2x, 3x, or 4x), but I suppose that will have to wait until 2012.


But it's not a plugin. Why not? Why is it you can buy a conversion kit to convert it to a plugin but Toyota will not offer this simple technology as an option? Can someone confirm this, is the European version a plugin?

Brian P

I wonder if they've fixed the power steering so that it actually feels like the steering wheel is connected to something ... the complete lack of steering feel and limp suspension turned me off the outgoing model. If not, the Insight is supposed to have better driving dynamics.


Not too exciting - but making a good car better often isn't.
Price ?
I wonder about the wording Gen 1 "was EPA rated at 41 mpg US combined ... current model, ... EPA rated at 46 mpg US, combined. ... estimated [sic] 50 mpg US combined for the new Prius.” Probably will be EPA rated at 50 or very close. ?
Either way they seemed to have made both acceleration and mpg better.
“preserved the triangle form” What triangle form?
“We expect a large portion of this volume to come from current Prius owners That’s because more than 90 percent say they will buy another Prius.” Right, when I have a car that I like, I trade it in.
I hope they sell to new buyers. But no matter, the trade ins will still be on the road.
No Wait – voices just told me Big Oil will buy them up and give them to GM to crush.

“Toyota forecasts first full calendar year sales in the US will be around 180,000 units.”
That’s 1.5% of US vehicle sales. Arghh.


It's not plug in because there is not enough battery to plug in.
Hymotion's $10,000 battery pack is bad ROI.
The car is not engineered to handle too much all electric driving. You can only drive upto 35 mph without the gas engine, and the amount of power and acceleration you get with the battery only is somewhat weak.

Wait until 2012 when the engineers can get it right.


The rather modest increase in mileage indicates diminishing returns for refining the Prius as we know it. That was to be expected.

It sounds as if they really made the car nicer even if the fuel economy is roughly the same.

Big advances now will come from different battery chemistry and drive train and plug-in recharging.

Even so a lot of makers would love to have an equivalent of the outgoing second-generation Prius in their dealers showrooms.


Two years ago Toyota's head of Prius development said that the 2010 Prius would have 9-miles of EV range.

This 1-mile EV range is a real U-turn from that, and I wouldn't be surprised if the 3rd generation battery is actually smaller (in kWh terms) than the 2nd generation battery!


I think that this new Prius is a wonderful evolution form the previous version. A 10% increase in fuel efficiency increase while also improving on handling AND performance is no small feat. The current Prius was already a very drivable car, and this new incarnation will be an even greater pleasure to drive.

Things i really like:
* Smarter use of breaking energy
* The radar "distance keeper" in combination with cruise control !!!
* LED headlights (no more garage work to replace a bulb!!)
* lower RPM on the highway
* Lower drag (even less wind noise)
* Green switch (optimized fuel efficiency)

Can't wait to go test drive it!!

Ps. I would have loved a Prius 3.0 with a smaller engine, bigger motor and LI-ION and plug in, but alas, the American consumer :-)

richard schumacher

It has a flying buttress! Woo-hoo! I'm sold :_>

Batteries Are Hard. I'm not going to buy the first year that the plugin option is generally available (2011; 2010 availability will be severely restricted as a beta test).


Those of you disappointed by the lack of PHEV option, read:
MIT Technology Review
Tuesday, January 13, 2009
Toyota to Deliver Plug-In Hybrids
The new Prius is designed so that its battery pack can be swapped out for a plug-in lithium-ion battery.


I think they have done an admirable job of continuous improvement. Now being in the 3rd generation, they are way ahead of everyone else in this hybrid technology. As is the tradition, american companies will now try to "leapfrog" and hope in this way to regain a competitive advantage. That may work, but the risks of failure are higher. The option is being plug in ready is great, although I did not see any particular place prewired for an outlet.

Stan Peterson

Progress continues incrementally. The Ford Fusion took a big step forward over HSD, and and this Prius is a small step too. Call it HSD Version II.

But it is easy to see that HEVs are reaching the end of the large expected improvements. Dual-mode HEVs wil improve highway mileage but it appears that 50+/60 mpg is about the maximum to be achieved in a "c" or larger segment car.

If you want more fuel economy you wil have to go to Parallel/Series PHEVs, and pure Series PHEVs like the sedan versions of the VUE dual mode PHEV, or the Volt architecture.

Fortunately, that is probably more than enough to fracture the OPEC cartel, and drastically reduce petroleum demand.


Is any manufacturer considering the Miller cycle for their hybrids? I haven't seen one except for Subaru's aborted plan. I would have thought that this would be the most efficient gasoline powerplant, and turbos are cheap these days.

Does it seem odd to anyone that both Ford and Toyota have both significantly increased the size of their hybrid engines? I'm perplexed.


I read where Toyota was asked about that and what they said was basically this...at highway speeds (an area they wanted to improve mpg) the larger engine was more efficient since they didn't have to rev it as high to produce the power needed and that was why they went with it.

With Ford, while it could be the same explanation, I think its really Ford deciding its cheaper to lift the drive system from the Escape Hybrid with virtually no changes and drop it in the Fusion Hybrid - then only make 25,000 of them, so people won't be able to get them.

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