These days, carmakers would need to offer a hybrid variant in order to penetrate the mid-sized sedan segment. Hyundai is no different as it has advanced through to the next stage of hybrid technology. It has made some tremendous progress in terms of battery power and in the methods on how it distributes power to the wheels.
The Hyundai Sonata has a hybrid system that is powered by a 2.4-liter Atkinson cycle four-cylinder engine that's partnered with a 30-kilowatt permanent-magnet motor. The Atkinson cycle improves fuel economy and cut emissions in hybrid powertrains by closing the intake valves later than normal.
Several of Hyundai's rivals use a continuously variable transmission for hybrids but Hyundai chose a six-speed automatic. Hyundai is able to do this since the electric traction motor is hard-coupled to the input of the transmission, replacing the torque converter.
With this Blue Drive system, drivers can choose either a performance or a fuel-economy mode. Hyundai offers a 43-kilogram (94.6 pounds) lithium polymer battery pack that was developed with LG Chem. It is lighter, smaller and more efficient than the nickel-metal hydride batteries that other mass-market carmakers offer.
Tesla and other niche players have been using lithium ion battery packs but Hyundai's model would be the first mass-production vehicle to offer such.
It is claimed that the 72-cell manganese-spinel lithium polymer pack is more durable and stable compared to lithium ion cells. Hyundai claims that the battery pack can be recharged numerous times to last for 300,000 miles and that at the end of its life, it would have lost only 10% of its initial performance.
Park Jin-ho, Hyundai's senior researcher for battery technology, revealed that the lithium pack is 15 to 20% costlier to build than the nickel-metal hydride units. But for that added expense, the customer gets a truly astounding Sonata Hybrid that can sprint from zero to 62 mph in 9.2 seconds faster than the Ford Fusion and Toyota Camry hybrids.
The Sonata Hybrid also returns 40 mpg on the freeway offering considerably better fuel economy than the Ford and Toyota. Reducing reliance on the engine is an electric oil pump and air-conditioning compressor. The Sonata Hybrid's 270-volt start-stop starter generator saves gasoline in a traffic jam. It also offers regenerative braking.