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Durable Lithium Polymer Battery
The 2011 Optima Hybrid's
outstanding efficiency is due in large part to the use of a lithium polymer
battery, which was developed in South Korea with partner LG Chem. The power and
energy density of this new battery type allowed Kia engineers to create a
lighter and more compact battery pack, with the 30 kilowatt battery pack
weighing just 95.9 pounds - 28 pounds less than the 2011 Toyota Camry Hybrid's
nickel metal hydride pack - which aids fuel economy and also helps to maximize
Optima's cargo space.
The Optima Hybrid's battery will hold its charge up
to 25 percent longer than hybrids with nickel metal hydride batteries, so the
battery is more likely to have usable energy available even if it has not been
in use. Both fuel consumption and emissions are cut, allowing more electric
starts and drive-aways. With that improved efficiency, more of the recovered
kinetic energy and charging energy from the engine is available to move the car
as necessary, which allows the vehicle to provide electric driving assist more
often and for a longer period. Lithium polymer also has less of the
self-discharge characteristic found in most rechargeable batteries.
Unique Hybrid Architecture
Unlike most current systems on the market,
the Optima Hybrid powertrain is configured with a unique architecture. Compared
to the power-split hybrid systems found on vehicles from Toyota or Ford, the
Optima Hybrid uses a Transmission-Mounted-Electric-Drive (TMED) layout with the
electric motor separated from the transmission gear-set. Offering several
advantages, this modular layout includes more efficient powertrain packaging,
use of many "off-the-shelf" components such as the existing six-speed automatic
transmission found on the 2.4-liter GDI Optima, and reduced engineering
investment. This also allows for other possible future combinations including
the application of more powerful motors and higher capacity batteries.
The Optima Hybrid also is among the first full hybrid systems on the market to
use a typical step-ratio automatic transmission. The extremely compact six-speed
automatic that debuted on the 2011 Kia Sorento CUV is carried over to the hybrid
largely unchanged. An external electrically-driven oil pump also has been added
to provide the hydraulic fluid pressure needed to keep the clutches engaged when
the vehicle is in idle stop mode.
The Optima Hybrid's electric motor is
hard-coupled to the input of the transmission and equipped with a permanent
magnet synchronous electric traction motor that produces 40.2 horsepower (30
kilowatt) and 151.2 pound-feet of torque when electric only, and an impressive
206.2 horsepower and 195.4 pound-feet of torque when in hybrid mode. This
replaces the torque converter, with a multi-disc clutch is fitted between the
engine and motor, enabling the gasoling engine to be de-coupled from the
powertrain for idle stop and electric drive modes. Employing this layout allows
the entire package, including a torsional damper, to fit virtually within the
same area as the traditional torque converter.
With the Optima also
weighing in as one of the lightest cars in the segment, high performance and
outstanding fuel efficiency are a natural result. The lightweight architecture
of the new Optima platform, combined with the lightweight lithium polymer
battery pack, brings the Optima Hybrid in at just 3,490 pounds, 230 pounds
lighter than the 2011 Ford Fusion Hybrid.
Beyond the Optima Hybrid's
innovative powertrain, Kia's engineers addressed all aspects of vehicle
efficiency including aerodynamics and rolling resistance. The Optima Hybrid
features unique exterior aero refinements, a lower ride height, an active air
flap system, lower drag wheels, and underbody aero tuning to reduce drag, while
low rolling resistance tires also help increase efficiency. The Optima Hybrid's
drag coefficient is an exceptionally low 0.26, among the best in the world.
The end result of the Optima Hybrid's highly-efficient powertrain,
low-rolling resistance tires, and clean aerodynamic signature is truly
exceptional highway fuel efficiency, the best of any mid-size hybrid sedan in
the market.
Safety-Minded
The 2011 Optima Hybrid is
equipped with a high level of standard safety features, as is the rest of the
entire Kia line-up. This includes six airbags3 (dual advanced front and
front-seat mounted side as well as full-length side curtain), front active
headrests, side-impact door beams, height-adjustable front seatbelts with pre-tensioners,
three-point seatbelts for all seating positions, Lower Anchors and Tethers for
Children (LATCH) and a Tire Pressure Monitoring System (TPMS). Four-wheel
antilock brakes (ABS), Electronic Stability Control (ESC), a Traction Control
System (TCS), a Brake Assist System (BAS) and Hill Assist Control (HAC) also are
standard.
Kia Optima Hybrid: Photo Gallery, Review (1/2) and Specifications