Automotive Engineering - February 2023 - 12

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Toyota punches up the Prius
The new car rides on what Toyota said is the second generation
of the Toyota New Global Architecture (TNGA) platform
for C-segment vehicles, or TNGA-C. Oya said for the Prius, the
architecture has a revised front MacPherson strut suspension,
crossmembers are different and the rear portion of the floorpan
is significantly altered to accommodate the new fuel tank
and lithium-ion battery pack (the Prius no longer will use nickel-metal
hydride batteries).
Oya said the target was to reduce weight of the underbody
The 2023 Toyota Prius is fully redesigned with low and sleek bodywork
that substantially departs from previous generations.
An undeniable technical achievement since its U.S. launch for the
2001 model year, Toyota's Prius never has been able to shake its
weenie-mobile reputation. It's an image formed largely by the
combination off oddball, aerodynamics-first styling and the pursuit
of ultimate fuel efficiency via low-power propulsion.
With EVs looming as the propulsion endgame and attention
to the 20th-century concept of " fuel-efficiency " waning,
Toyota's said " enough! " The 2023 Prius bodywork now is
smooth, low and sleek, so different that there's virtually no visual
connection to its trippy forerunners. Under the hood is a
larger, powered-up 4-cyl. engine and similarly boosted drive
motor that, combined, take the Prius to 194 hp (196 hp for
AWD models) - a 60% jump over the wheezy 121 combined hp
of its predecessor. Almost paradoxically, though, the 2023 Prius
still sips gasoline at pretty much the same pace - up to a 57
mpg (4.1L/100 km) combined rating for the most-efficient LE
trim in front-wheel drive. The low is the 49 mpg (4.8L/100 km)
combined rating for the top-trim XLE in AWD layout.
Chief engineer Satoki Oya told SAE Media that the new Prius'
revised Dynamic Force 2.0L Atkinson-cycle 4-cyl. (M20A-FXS)
enjoys the same exemplary 41% brake thermal efficiency (BTE)
as the previous, fourth generation of the engine. But Lisa
Materazzo, group vice president of marketing, said the new
car's design, rather than its efficiency, may be the attribute to
lure the younger buyers Toyota hopes to attract.
TNGA revised
The 2023 Prius' slippery new profile displays its most striking
dimensional change, a 2-inch (51-mm) lower roofline. The new
car also is 1 inch (25.4 mm) wider and slightly longer, with
wheelbase increased by 2 in. The windshield rake would be
considered fast for nearly any vehicle but is particularly so for a
Prius. Oya said the new shape's drag coefficient - 0.27 Cd - is
on paper worse than the previous Prius' 0.24, but the sharper
front end and grille create less frontal area, reducing CdA and
effectively negating the detrimental overall aerodynamic effect
of the new bodywork.
12 February 2023
to help offset the 2023 Prius' larger engine and the use of
bigger wheels and tires (17-inch for the base LE trim and 19inch
for XLE and Limited models). Curb weight nonetheless is
up slightly for the fifth-generation Prius, ranging from 3097
lb. (1404 kg) for the front-drive LE to 3340 lb. (1515 kg) for an
AWD Limited.
More engine, more motor
Nobody will carp that the new Prius doesn't perform better -
much better. The 2L direct- and indirect-injected 4-cyl. develops
150 hp; the previous 1.8L engine managed just 96 horses.
The new 2L engine's hike to a 14:1 compression ratio led to
concern about required fuel octane, but Toyota assured journalists
at the media introduction that maximum performance
is achieved on 87-octane regular unleaded gasoline.
The central electrified component of the hybrid system, the
permanent-magnet AC electric motor Toyota refers to as motor-generator
2, also is vastly upgraded. Thanks largely to a
doubling of magnets to six per pole, power output increases to
111 hp, a 40-hp boost compared to the outgoing Prius' MG2.
Torque also is enhanced by some 20%, to 152 lb-ft (206 Nm)
versus the previous 120 lb-ft (163 Nm), yet the new design
means the motor is smaller and lighter. The company said the
222-volt/4.06 amp-hour lithium-ion battery pack is 14% lighter
yet 14% more powerful.
The Prius cabin is completely redesigned to include an instrument
cluster directly in front of the driver and the gear selector in a more
conventional location.
AUTOMOTIVE ENGINEERING
BOTH IMAGES: TOYOTA
Automotive Engineering - February 2023

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