 2011 Hyundai Sonata Hybrid. Click image to enlarge |
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2011 Hyundai Sonata Hybrid
San Diego, California – So called “full” hybrid vehicles – those that can run on engine power, battery power or both at the same time, such as the Prius, Camry Hybrid, Fusion Hybrid and Altima Hybrid – are known for their excellent fuel economy but are often criticised in the media for their uninspired driving experience. At Autos, we’ve made mention of the “rubber band effect” created by their continuously variable transmissions (CVTs), the occasional jerky transitions from gas engine to electric motor, vague steering feel, poor handling, grabby brakes, and hard ride. As the technology has progressed over the past decade, we’ve also noticed some improvements in steering feel, ride, power and smoothness. Still, most hybrids today aren’t as entertaining to drive as their non-hybrid counterparts.
The 2011 Sonata Hybrid sedan, Hyundai’s first hybrid car, has addressed many of these driveability issues, and though it’s certainly not yet a sport sedan, it has made improvements without compromising the excellent fuel economy people expect from hybrids.
Using a six-speed automatic transmission instead of a CVT, the Sonata Hybrid has eliminated the irritating engine droning and “rubber band effect” typical in “full” hybrids when accelerating. The six-speed automatic transmission gives the Sonata Hybrid a more traditional “stepped” shift feel. This may seem relatively unimportant, but it brings the Sonata Hybrid closer to the driving experience that most drivers are familiar with.
    2011 Hyundai Sonata Hybrid. Click image to enlarge |
The Sonata Hybrid’s powertrain, which Hyundai calls “Hybrid Blue Drive”, consists of a 166-horsepower 2.4-litre “Atkinson Cycle” four-cylinder engine, a starter-generator, 30 kW electric motor, low friction oil pump (which eliminates the torque converter), and the six-speed automatic transmission. It puts out a combined 209 horsepower, more than the Camry (187), Fusion (191) and Altima (198) hybrids. Its 30kW electric motor delivers 151 lb.-ft. of torque from 0 to – 1,400 r.p.m., providing quick take-offs. And with a lower curb weight (1,574 kg) than its rivals, the Sonata Hybrid has a better power to weight ratio. Its 0 to 100 km/h should be faster than the Camry Hybrid’s time of under nine seconds, but this is yet to be determined.
Another difference between the Sonata Hybrid and its competitors is that it can operate in electric-only mode at higher speeds: up to 100 km/h compared to a maximum of around 60 to 80 km/h for other hybrids. As a result, it is more fuel-efficient on the highway than many hybrids, with a published highway fuel economy rating of 4.6 L/100 km – better than the Camry Hybrid’s 5.7 L/100 km and equal to the Fusion Hybrid’s 5.4 L/100 km. Like other full hybrids, it can also run on electric-only power at slower speeds where it’s rated at 5.5 L/100 km. The Sonata Hybrid’s gas engine shuts off automatically when the vehicle is stopped and starts automatically as the brake pedal is released. The power steering, power brakes, heater and air conditioner are all powered electrically, and operate independently of the engine. The 270-volt hybrid battery, located behind the rear seats, is recharged while coasting and braking.
A technological breakthrough for Hyundai is the company’s new lithium polymer battery pack, developed by LG Chem and Hyundai Auto in Korea, and currently exclusive to Hyundai. Hyundai claims this battery technology is superior to the nickel-metal hydride batteries used in most other hybrids and lithium-ion batteries being developed for plug-in hybrids, extended range electric cars (Chevy Volt) and pure electric cars. Compared with nickel-metal hydride batteries, lithium polymer batteries are 20 to 30 per cent lighter, 20 per cent smaller, and offer 1.7 times more energy density and 10 percent greater efficiency. Lithium polymer batteries also hold their charge 1.25 times longer, and are more resistant to changes in temperature. Lithium polymer’s self-discharge rate is less than a third of a nickel-metal hydride battery.
