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A look at Toyota's fourth generation of hybrids

Sunday, January 1, 2017 - 09:00
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Nearly 20 years ago, Toyota Motor Sales introduced a vehicle that would change the way the world saw hybrids. With more than 3.5 million units sold, the fourth generation of Prius seeks to build on a legacy while ushering in a new generation of Toyota hybrid technology. With a re-engineered design, the new Prius utilizes the Toyota New Global Architecture (TNGA) chassis as well as body, engine and technology improvements. With estimated combine EPA fuel economy numbers of 52 MPG on regular gasoline and retail pricing at under $30,000, this platform is sure to see continued success. We will look at the fourth generation THS technology and what you will need to know to repair these vehicles in the independent repair market.

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(Image courtesy of Toyota Media) The new Prius looks toward the horizon of the next generation of Toyota Hybrids
(Image courtesy of Toyota Media) The dash display on the new Prius

1.8L engine
While Toyota has used a 1.8L engine in the Prius in the past, this newly designed 1.8L has been completely reimagined with fuel economy, overall performance and emissions in mind. Every manufacturer seeks to squeeze every bit of thermal efficiency and light weighting; Prius’ 1.8 is exemplary. Toyota claims a 40 percent maximum thermal efficiency achieved through the use of a new large-volume, cooled EGR system that has the ability to operate at maximum engine loads (unlike EGR systems we have been familiar with in years past) as well as advances in combustion chamber and intake design.

Running an internal combustion engine in a hybrid brings with it the challenge of establishing operating temperature quickly. In order to achieve this, exhaust gasses are used to heat the coolant to speed engine warm-up. A motorized shutter-style grille is also used to block the flow of air in cold climates to speed engine warm-up.

(Image courtesy of Toyota Media) The new improved Toyota 1.8L

P610 transaxle
The transaxle in the Prius has been completely redesigned. While it still uses two motor-generators (MG1 + MG2), the planetary gear set has been refined with the use of parallel gears.

High-voltage battery
The heavy nickel-metal hydride batteries have been replaced with new, more energy-dense units that allow for a smaller battery that fits under the seat as opposed to earlier generations that sacrifice precious cargo space. A new lithium-ion battery will replace most the nickel-metal hydride battery.

(Image courtesy of Toyota Media) Newly designed Nickel-metal hydride battery pack
(Image courtesy of Toyota Media) Newly designed Toyota Lithium Ion Battery pack
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