Hyundai has announced that its all-new 2011 Sonata will be the first vehicle to offer gasoline direct-injection (GDI), twin-scroll turbochargers and full-hybrid powertrains. Unveiled at the New York auto show, the Sonata Hybrid is Hyundai’s first hybrid in the US market. Its Hybrid Blue Drive can operate on an electric motor, gasoline internal combustion engine or a combination of the two depending on driving conditions and driver demands. It's also the only hybrid using lithium polymer battery technology.

Hyundai Hybrid Blue Drive uses the company’s compact new six-speed transmission, modified with hybrid starter-generator, electric motor, and low-friction oil pump, which eliminate the need for a torque converter.

Hyundai says its Hybrid Blue Drive is the only system currently using lithium polymer battery technology – choosing this form of power storage over nickel-metal hydride and lithium-ion applications. Lithium polymer incorporates the benefits of lithium-ion (as used in laptops and cell phones) and provides robustness, power-density and package flexibility, all of which suit automotive applications.

“The Hyundai Sonata Hybrid is the new kid on the block, but it’s not a follower,” says John Krafcik, president and CEO, Hyundai Motor America. “Its full parallel hybrid configuration and breakthrough lithium polymer batteries offer a new take on traditional hybrid design, while its unique design sets it apart from the mid-size hybrid pack.”

According to the EPA, Hyundai has led the US industry in fuel economy for 2008 and 2009, and is currently the only automaker with average fleet fuel economy of more than 30mpg.

“Hyundai applies advanced technologies to vehicles to provide the best solutions for the everyday driver,” said Krafcik. “Unlike traditional hybrids that trade off highway fuel economy for higher city ratings, the Sonata Hybrid delivers best-in-class highway fuel economy, while still delivering about a 40 percent improvement in city fuel economy compared to a Sonata equipped with the Theta II GDI engine. We think this is a better balanced approach for the majority of car buyers.”

Efficiencies in the city and on the highway

Hyundai says the Sonata Hybrid will deliver best-in-class highway fuel economy of 39mpg offers and city fuel economy of 37mpg. It says government studies have shown that the typical US driver operates in a highway mode 57 percent of the time, therefore, the company’s approach to delivering impressive fuel economy in highway mode differentiates Sonata Hybrid from other mid-size sedan hybrid vehicles such as the Toyota Camry Hybrid and Ford Fusion Hybrid. While the Sonata Hybrid delivers the standard hybrid fuel economy gains in the city like its competitors, Hyundai says it provides drivers with greater fuel economy on the highway, where its competitors fall short.

Sonata Hybrid in electric mode hits a top speed of 62mph. Its gasoline engine engagement depends on the vehicle’s state of charge, acceleration and speed. Its two propulsion units develop a total output of 209hp at 6,000 rpm and delivering 195lb-ft of torque.

The Sonata Hybrid is also the lightest vehicle in its class (3,457lbs, 263lbs lighter than the Fusion Hybrid), thanks to its lithium polymer battery pack and other weight loss gains. Reduced weight boosts performance and energy efficiency.

Hybrid Blue Drive

At the heart of the Sonata Hybrid is the proprietary parallel hybrid drive system that uses the power from the electric motor more efficiently to directly control the vehicle, allowing it to be operated at much higher speeds than the competition in EV-only mode. That’s because the wheels are turned by power coming straight from the gasoline engine, or the electric motor, or both together, as conditions demand.

The Hybrid Blue Drive runs on the fuel-efficient 2.4L Theta II engine (169hp at 6,000rpm and 156lb-ft of torque at 4,500rpm) mated to a six-speed automatic transmission and a 30kW (151lb-ft) electric motor to extract the best fuel economy.

In the Hyundai Hybrid Blue Drive system, the Theta II with multi-port fuel injection (MPI) operates on an Atkinson Cycle, a strategy that increases fuel efficiency in internal combustion engines through changes in compression and power strokes in the four-stroke engine. It is typically only used in hybrid systems where the high-torque electric motor boosts low-end power, which is traded off for internal combustion engine efficiency.

All of the Theta II major driveline and cooling system components have been optimized to reduce friction. Hybrid Power Control (HPC) management software automatically shuts off the engine when the vehicle comes to a halt, cutting emissions to zero. During deceleration, braking regeneration comes into play and the system also features “smart brake” technology in which braking input overrides accelerator pedal input.

The all-aluminum, 16-valve engine also features Continuously Variable Valve Timing (CVVT) on both camshafts and newly developed engine components to reduce friction. This optimized Theta II engine achieves 10 percent better fuel consumption over a conventional Theta II engine.

Hyundai Hybrid Blue Drive uses the company’s proprietary six-speed automatic transmission, replacing the torque converter with an electric motor and high-efficiency oil pump. This technique uses a traditional step-shift six-speed transmission rather than a CVT to provide a more traditional shift feel that is preferred by customers and sometimes artificially replicated in CVT applications. Hyundai say this is a cheaper option, robust and a simple solution.

In another measure to improve fuel efficiency, the top three gear ratios in the transmission have been extended to ensure the engine runs at lower RPMs, the electric motor-assisted steering system reduces demands on the engine.

Lithium polymer batteries

Sonata’s hybrid system stores its electrical charge in a 270V Lithium polymer rechargeable battery (5.3Ah/270V) that is 20-30 percent lighter than a nickel-metal hydride battery (95.9lbs versus the Camry Hybrid’s 123.9lbs) and offers 1.7 times more energy density. This gives the Sonata Hybrid less weight and more space and the company says that the Lithium polymer batteries hold their charge 1.25 times longer, too. Its self-discharge rate is less than a third of a nickel-metal hydride battery.

Compared to Lithium-ion batteries, Lithium polymer has lower manufacturing costs, is more resistant to physical damage and can handle more charge-discharge cycles before storage capacity begins to degrade.

Rather than using a liquid electrolyte, which requires a robust metal casing, lithium polymer batteries use a polymer gel as the electrolyte, which allows the use of a thinner and lighter aluminum-walled pouch. Inside each lithium polymer cell, the cathode, separator, and anode are laminated together, enabling much simpler and more reliable manufacturing. This allows the battery pack to be about 20 percent smaller than a lithium-ion battery pack. On the outside

Hyundai designers have given the Hybrid model a modern, eco-friendly design, with “at-a-glance” differentiation from the non-hybrid Sonata models. It has unique headlights and taillights; aerodynamic bumper fascias; aerodynamic rocker panels; bold hexagonal grille; eco-spoke wheels; air dam and aero side sills; exclusive hybrid paint color; interior refinements; supervision cluster with eco-display options; unique interior color choice and unique seat patterns.

There's also a Technology Display featured on a 4.2-inch LCD screen located between the odometer and tachometer, or visible on the optional seven-inch navigation screen. It shows driving mode; energy flow within the vehicle; engine and motor movement; fuel level; battery power levels and charge status; electric vehicle mode indicator and average and instant mpg.

No word yet on pricing or availability.

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