By Kim Da-ye
Hyundai Sonata Hybrid, displayed at the Seoul Motor Show 2011 last week, isn’t just another hybrid vehicle.
With many existing eco-friendly technologies patented by Japanese firms, Hyundai Motor, Korea’s largest automaker, succeeded in avoiding patent infringement by inventing its own hybrid drive system.
Full-hybrid technology is known to be difficult and complex to develop, and only a handful of automakers including Japan’s Toyota Motor and General Motors of the U.S. have done so,” Kim Pil-soo, auto expert and professor at Daelim University, said.
“It is meaningful that the full hybrid mid-size sedan has dodged patents registered by the Japanese and that the nation’s first hybrid car is built on domestic, cutting edge technology.”
The hybrid vehicle market is nearly saturated with patents. Toyota is known to have more than 4,000 hybrid-vehicle related patents in the U.S. which represents more than 40 percent of all relevant patents filed, the American tech publication, Wired, wrote last July.
While the Japanese juggernaut tries to cash in from licensing key technologies and to hinder other automakers’ green car development, ironically, it was also sued several times for patent infringement.
Toyota, for instance, settled last July a case brought by on Paice, a small company set up by a Russian-American university professor who had patented a form of hybrid vehicle technology in 1994.
Sonata Hybrid and Kia Motors’ K5 Hybrid adopt a parallel hybrid system while their competitors including Toyota use power split technology.
The Blue Drive hybrid system places the relatively small electric motor between the engine and the transmission and uses a clutch to control power from the engine.
At low speeds, the clutch disconnects and the vehicle drives in the full-electric mode with the motor. At a high speed, the clutch connects, turning on both the motor and the engine.
When the car slows down, the battery charges from regenerative breaking, and once returning to a lower speed, it drives on the charged battery.
Hyundai installed the newly developed two-liter Nu hybrid engine that produces 150 horsepower and the 30kW hard-type hybrid motor that generates 41 horsepower. The vehicle has 191 horsepower in total, and both the Sonata and the K5 show a fuel efficiency of 21 kilometers per liter (km/l), compared to Toyota Prius’ 29 km/l.
In Toyota Prius, the most-famous hybrid vehicle that represents the power-split technology, the “planetary gear set” replaces the role of Sonata’s clutch.
A set of gears connect the engine, the generator and the motor. At a low speed, the gear that connects to the motor turns on, working the electronic motor and switching another gear that starts the generator.
When reaching a certain speed, the engine turns on, provided by extra power from the generator.
The usage of the clutch was Hyundai’s idea to produce hybrid vehicles without overlapping Toyota’s technology, a Hyundai Motor official said.
He said that the automaker is investing in eco-friendly cars including electric vehicles and hydrogen fuel cell cars more than ever, but the budget is still small, which he described as “a drop in the ocean" compared to the investment by Toyota.
When asked how Hyundai could come up with its own hybrid system with a limited budget, he said it may be due to the hardworking, brainy research team.
Both the Sonata Hybrid and the K5 come with a six-speed automatic transmission tailored for hybrid vehicles which Hyundai Motor Group touts as the world’s first of its kind.
Compared to the continuously variable transmission (CVT) built in the Prius, the Hyundai official said that the six-speed transmission could make driving more fun.
In addition, Hyundai claimed in a press release, “The top three gear ratios in the transmission have been extended to ensure the engine runs at lower RPMs and the electric motor assisted system reduces demand on the engine.”
Hyundai also touts using lithium polymer batteries manufactured by LG Chem instead of the more common nickel-metal hybrid batteries.
“Lithium polymer batteries deliver the same power with 20 to 30 percent less weight, 40 percent less volume and 10 percent greater efficiency over the nickel-metal hybrid batteries found in today’s hybrids,” Hyundai said. They also offer 1.7 times more energy density than their counterparts and their charge lasts 1.25 times longer.
Hyundai launched hybrid vehicles such as the Avante LPi hybrid in the past. But they were “mild hybrids” that merely added a motor to the liquefied petroleum gas (LPG) engine.
A mild hybrid vehicle uses mainly the engine and gets the extra power from the electric motor. The structure results in only a limited saving of energy, Kim Pil-soo said.
Kim added that for Sonata Hybrid and K5 Hybrid to take off, the government will have to actively promote hybrid vehicles to turn around the public’s perspective on eco-friendly cars.
“Views on the existing LPi hybrids aren’t always favorable, and some consumers do not like them for their high prices. Hybrid vehicles need publicity for the public’s approval of the technology like that in Japan.”