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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