Hyundai goes high-tech with Sonata, its first hybrid

SEOUL--A hybrid variant is the cost of entry in the midsized sedan segment these days. Hyundai is joining the fray with the next stage of hybrid technology, both in terms of battery power and in how the power is delivered to the wheels.

The basics: Hyundai's hybrid system on the Sonata teams a 2.4-liter Atkinson cycle four-cylinder engine with a 30-kilowatt permanent-magnet motor. The Atkinson cycle closes the intake valves later than normal to improve fuel economy and cut emissions in hybrid power trains.

While some competitors use a continuously variable transmission for hybrids, Hyundai went with a six-speed automatic. It can do this because the electric traction motor is hard-coupled to the input of the transmission, replacing the torque converter. The Blue Drive system also offers drivers the choice of a performance or fuel-economy mode.

Notable features: Hyundai's 43-kilogram (94.6 pounds) lithium polymer battery pack, developed with LG Chem, is lighter, smaller and more efficient than the nickel-metal hydride battery offerings from other mass-market automakers. Although niche players such as Tesla are using lithium ion battery packs, Hyundai is the first to offer lithium in a mass-production vehicle.

Hyundai claims the 72-cell manganese-spinel lithium polymer pack is more durable and stable than lithium ion cells. Hyundai says the battery pack can last for 300,000 miles' worth of rechargings, with only a 10 percent loss of performance at the end of life.

The advances come at a price: The lithium pack is 15 to 20 percent more expensive to build than the nickel-metal hydride units, said Park Jin-ho, Hyundai's senior researcher for battery technology.

Hyundai says the Sonata Hybrid accelerates to 62 mph in 9.2 seconds, quicker than the Ford Fusion and Toyota Camry hybrids, and also that it gets 40 mpg on the freeway, significantly better fuel economy than the Ford and Toyota. An electric oil pump and air-conditioning compressor reduce reliance on the engine. A 270-volt start-stop starter generator saves gasoline in urban gridlock, and there's regenerative braking as well.

While other automakers offer little design variation on their hybrids, the Sonata Hybrid has an entirely different front fascia. A howling hexagonal grille opening is more suited to a performance sedan. It also gets different tail lamps and five-spoke wheels, designer Casey Hyun said. The design engineers made the car more slippery, with a .25 coefficient of drag, compared with .28 for the base Sonata.

What Hyundai says: "The most important thing was how smooth and fast we could control the engine clutch [between engine-powered and hybrid-drive modes] without sacrificing driveability," said Lee Ki-sang, senior vice president of Hyundai's hybrid vehicle engineering group.

Compromises and shortcomings: Despite the advances, the Sonata Hybrid is not a true parallel hybrid. Hyundai acknowledges that its hybrid system generates less electric power than competitors' offerings. Although Hyundai claims its "EV Mode" can work up to 62 mph, it requires a feather-footed driver to keep the engine from firing up while driving. Unlike the rest of the U.S.-made Sonata lineup, the hybrid will be built in South Korea.

The market: Hyundai predicts 5 percent to 7 percent of Sonatas sold will be hybrids, which means about 15,000 units a year.

The skinny: Journalists were given very brief test drives of the car, which is still in pre-production mode. U.S. sales begin this fall. Acceleration was brisk; cornering was not ponderous despite the added weight; and the switch between gasoline and battery power isn't startling. If the goal is a seamless transition of driving styles, the Sonata Hybrid appears to have achieved it.

(Source: Automotive News)