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| Ecotec 2.0L turbocharged engine including the direct injection fuel system, continuous variable valve timing for both intake and exhaust valves and the turbocharger. Click to enlarge. |
The 2011 Buick Regal Turbo will feature the first flex-fuel capable direct-injected turbocharged engine in a production car. GM has produced more than 5 million flex-fuel models over the last 15 years, and has a goal of offering more than 50% of its production in flex-fuel models by the end of 2012.
Estimated EPA fuel economy numbers for the new turbo running on gasoline are 20 mpg city/32 hwy mpg (manual) and 18 mpg city/28 mpg hwy (automatic). Running on pure E85 would result in about a 20% decrease in fuel economy, GM said.
Compared to earlier versions of the 2.0-liter Ecotec turbo, GM powertrain engineers have upgraded the new engine to accommodate both E85 and to incorporate other refinements.
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| Direct injection fuel system including fuel rail and injectors, high pressure cam-driven fuel pump and the E39 engine control module (cover removed) containing the “Viper” 32 bit microprocessor. Click to enlarge. |
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% 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 meet durability requirements.
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.
The 2.0-liter Ecotec turbo produces 258 lb-feet (350 N&iddot;m) of torque from 2,000 to 5,500 rpm making it feel like a much-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.