The Kia 2011 Optima midsize sedan lineup has expanded with the introduction of the all-new Optima hybrid at the recent Los Angeles Auto Show.

With a roomy interior, and an estimated 40mpg class-leading fuel efficiency, Kia’s first-ever hybrid in the US will attract those looking for a well-equipped sedan that does not sacrifice style, comfort, performance or value for fuel efficiency.

Set to hit showrooms early next year, the Optima Hybrid employs a Kia-developed powertrain that includes several innovations enabling it to provide exceptional hybrid performance and efficiency, says Kia.

“Kia Motors is aggressively expanding its green car investments and R&D in much the same way we committed ourselves to the quality and design innovations over the last decade that have fueled our dramatic brand transformation,” said Michael Sprague, vice president, marketing & communications, Kia Motors America.

“By adding our first-ever hybrid in the US to the Optima lineup we are providing consumers with three powerful and fuel-efficient powertrain choices, and continuing Kia’s philosophy of offering stylish, value-packed vehicles with outstanding fuel efficiency.”

The 2011 Optima Hybrid uses a full parallel hybrid system and can be driven in zero emission, full-electric drive mode at speeds up to 62 miles per hour or in blended gas-electric mode at any speed. When the car comes to a stop and the electrical load is low, the engine shuts off to completely eliminate idle fuel consumption and emissions.

The 2011 Optima Hybrid’s 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, Kia said in a release.

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 – it aids fuel economy and also helps to maximise Optima’s cargo space.

According to Kia, the Optima Hybrid’s battery will hold its charge up to 25 per cent 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, Kia said in its release.