The 2011 Buick Regal Turbo is the first direct-injected turbocharged production car capable of running on any blend of gasoline or E85 ethanol, joining more than 5 million flex-fuel models General Motors has produced over the last 15 years.
The turbocharged Ecotec 2.0-liter inline four-cylinder engine that powers the Regal will help GM reach its goal of offering more than 50 percent of its production in flex-fuel models by the end of 2012.
Attendees at the National Ethanol Conference in Phoenix will had the opportunity to drive the Regal and the flex-fuel GMC Terrain during conference breaks Monday.
Compared to earlier versions of the 2.0-liter Ecotec turbo, GM powertrain engineers have significantly upgraded the new engine to accommodate both E85 and other refinements.
Since ethanol requires a richer air-fuel mixture than gasoline, flex-fuel engines need higher flow-rate injectors. However, a flex-fuel engine can potentially have any combination of gasoline or up to 85 percent ethanol in the tank, so a sensor in the fuel system measures the blend in real-time. This allows the engine management system to automatically adjust the mixture to provide improved performance and reduced emissions and fuel consumption. Stainless steel fuel lines provide extra corrosion resistance to ensure that the Regal Turbo meets GM’s stringent durability requirements.
In the past, improving power output and reducing fuel consumption and emissions were often conflicting goals. By delivering fuel directly to the combustion chamber, the high-pressure injectors can now provide a more precise mixture for optimum combustion.
Turbochargers use the energy in the hot exhaust gas flow to drive a compressor that forces more air into the combustion chamber for on-demand power delivery. The twin-scroll turbocharger on the Ecotec engine provides two inlet paths to the turbine to maximize the kinetic and thermal energy delivered to the turbine.
“Lag and reduced vehicle launch response is one of the age-old concerns with previous turbo engines,” said Ecotec chief engineer Mike Anderson. “Drivers would step on the gas to accelerate and then have to wait for boost and power to be generated. The twin-scroll turbocharger helps the engine generate power and torque when the driver needs it for passing maneuvers or merging onto a highway even at low engine speeds.”
Anderson said the 2.0-liter Ecotec turbo produces 258 pound-feet of torque from 2,000 to 5,500 rpm, making it feel like a larger V6 engine while still delivering four-cylinder efficiency.
Other changes to the turbo engine for 2011 include a new precision sand cast aluminum cylinder block that provides better durability while transmitting less noise and vibration than lost foam casting used previously.
The end result is a quieter and more refined power plant that helps the Regal achieve best-in-class levels of noise, vibration and harshness while delivering the performance expected of the best import sport sedans and the ability to operate on current and next-generation renewable biofuels.
More at www.buick.com.