Hyundai Lithium Polymer Hybrids Coming to the U.S.

by Bill Siuru

12/08/2008

With its newly inaugurated Blue Drive environmental initiative, Hyundai is striving to become the world’s most fuel efficient automaker. Its efforts will include hybrid electric vehicles. Because Hyundai doesn’t currently market a hybrid in the U.S., most Americans don’t realize that the South Korean company, and its affiliate Kia, are seriously involved in developing in HEV technology. Hyundai developed its first HEV prototype in 1995, followed by Elantra and Accent prototype HEV models. It has delivered over 2,800 Hyundai Getz and Accent HEVs to Korean government agencies as part of a fleet demonstration project since 2004.

In July 2009, Hyundai plans to start selling the Hyundai Avante LPI, the first hybrid to combine advanced lithium-polymer (Li-Po) batteries with an internal combustion engine modified to run on LPG (liquid petroleum gas) or propane, initially in Korea. The Avante is based on the Elantra model.

Hyundai unveiled its Santa Fe blue Hybrid at the recent Paris Motor Show. Based on the top selling Santa Fe SUV, the Blue Hybrid variant uses a parallel hybrid drive system developed in-house by Hyundai engineers. Hyundai says this proprietary hybrid architecture will be used on all its future HEVs including a third-generation Sonata that will be sold in the U.S. in 2010.

Hyundai’s 2.4-litre Theta engine is mated to a six-speed automatic transmission and a 30 kW electric motor that also functions as a generator for regenerative braking. For maximize fuel economy, all of the Theta's major driveline and cooling system components have been optimized to reduce friction. That includes filling the crankcase with low friction oil.

Hyundai Santa Fe Blue Hybrid's Theta engine

The Theta's engine control software governing injection pressure, engine cycle timing, and exhaust retreatment rates has been revised to further reduce fuel consumption. There is also a stop-start capability in which the engine is shut off rather than allowing it to idle in most circumstances. When pressure is applied to the accelerator pedal, the Integrated Starter Generator (ISG) automatically restarts the engine.

The transmission’s top three gear ratios have been extended to ensure lower engine rpms to further enhance fuel economy. Other fuel saving items include electrically-assisted steering and low rolling resistance tires.

Hyundai Santa Fe Blue's volt lithium polymer battery

For the Santa Fe hybrid, this all adds up to a combined city/highway fuel consumption of 38 mpg and carbon dioxide emissions 148 grams/km. The Santa Fe Blue Hybrid has as an estimated top speed of 105 mph and can accelerate from 0- 60 mph in 10.6 seconds.

A 5.3 amp-hour, 270 volt lithium polymer battery is located beneath the rear floor. Lithium polymer was chosen over lithium-ion chemistry because of its greater energy density and lower manufacturing costs. According to Hyundai, Li-Poly battery is also more resistant to physical damage and can also take more charge-discharge cycles before storage capacity begins to degrade.

Hyundai Santa Fe Blue's three-piece panorama sunroof

The Santa Fe Blue Hybrid features an innovative three-piece panorama sunroof. The moveable glass top has UV filtration to reduce thermal loading without restricting the transmission of light. An adjustable shade, operated separately from the glass top, protects occupants against solar radiation, The modular system was developed by Magna Car Top Systems.

The Sonata hybrid for the U.S. market will use the 30 kW electric motor paired with a 2.4-liter four-cylinder engine and lithium polymer battery developed with battery supplier LG Chem. It will have start/stop capability and the ability to run solely on battery power for short distances. Hyundai claims this third-generation battery technology can deliver the same power as a nickel-metal-hydride battery pack while taking up half the space, and is additionally 20 percent smaller than a lithium-ion battery counterpart. Hyundai also points out that lithium polymer batteries use simpler construction than Li-ion batteries, which should translate into decreased cost. Hyundai plans a 10-year/150,000-mile life for the batteries.