The Hyundai Sonata 2.0L Turbo Engine: a review of Hyundai’s new turbo engine
At the recently concluded New York Auto Show, Hyundai Motor America presented the new 2011 Sonata which debuts the 2.0L Theta II turbocharged gasoline direct-injection (GDI) engine.
With about 34 mpg highway rating and 274 horsepower, the new 2011 Sonata is now leading the segment as it combines fuel efficiency and power, thanks to the all-new 2.0L Theta II turbocharged GDI engine.
Hyundai has come up with two industry-leading initiates, which are “24/7” and “Hyundai Blue Drive”, and the new Sonata is part of these. “24/7” has set Hyundai to producing seven new models in 24 months, while “Hyundai Blue Drive” is an environmental initiative in fuel efficiency and sustainability.
These two initiatives will produce four nameplates with GDI or the combination of GDI technology and a turbocharger, and the new Sonata is the first Hyundai car to have both GDI technology and a turbocharger.
“The Sonata 2.0 Turbo is a great example of what our Blue Drive product strategy is doing for consumers. Think about it – more horsepower than any of our V6 competitors, with better gas mileage than any competitive 4-cylinder model. We are not fans of compromising at Hyundai, and the Sonata really demonstrates this aspect of our business approach,” said John Krafcik, president and CEO of Hyundai Motor America.
With the 2.0-liter turbocharged GDI four-cylinder engine, the 2011 Sonata rides on 274 horsepower at 6,000 rpm and 269 lb-ft of torque from 1800-4500 rpm using only regular fuel, and with preliminary estimate of delivering 22 mpg city and 34 mpg highway.
The Sonata’s vaunted engine has a twin-scroll turbocharger. Combine this with the GDI system and the car produces instant power delivery. With GDI, Hyundai has once again proven to apply its efficient technology in high volume to its most popular model because twin-scroll turbochargers are usually used only on more expensive high performance engines.
The 2.0T engine will be available on the Limited trim and SE level. The 2.0T Limited Edition would include a panoramic sunroof, dual exhaust system, 18-inch hyper silver alloy wheels, and steering wheel-mounted paddle shifters.
About GDI Technology and Twin-scroll Turbocharger
The twin-scroll turbocharger design features two exhaust gas inlets separated by split walls inside the turbine housing. Both gas passages are controlled by a waste-gate, and thanks to the divided manifold, each of the two twin-scroll turbo recovers more energy from the exhaust than does a single-scroll turbocharger.
The pressure distribution in the exhaust ports are improved and the delivery of exhaust gas energy to the turbocharger’s turbine becomes more efficient primarily because the cylinders, whose exhaust gas pulses interfere with each other, are separated by the twin-scroll design.
For example, as cylinder one starts its intake stroke when both its intake and exhaust valves are open (valve overlap period), the exhaust stroke of cylinder three already starts with the exhaust valve open.
If their exhaust passages were connected, cylinder three’s exhaust gas pulse would increase cylinder one’s back pressure. This reduces the induction of fresh air and increases hot residual gases inside the cylinder. The twin-scroll turbocharger design minimizes this interference.
Other advantages of the twin-scroll turbocharger design include an improved combustion efficiency, low engine-speed efficiency, and better pressure distribution among others.
The two main features of the Hyundai twin-scroll turbocharger are its stainless steel exhaust manifold and the twin-scroll turbine housing are joined in a one-piece design and (2) the turbocharger’s waste-gate uses a motor-driven electric controller instead of a mechanical controller.