Buick Regal introduces direct inject turbo FFV in US

By Holly Jessen | February 24, 2011

Buick has introduced a flex-fuel vehicle that combines power and fuel efficiency. The 2011 Buick Regal Turbo packages turbo charging with direct injection and, new this year, flex-fuel capability. The 2.0-liter Ecotec turbo engine was refined from previous versions and significantly upgraded to accommodate E85.

General Motors has been selling this type of engine in Europe but was unable to bring it to the U.S. due to marketing and technical issues, said Coleman Jones, the company’s biofuels implementation manager. Likewise, direct injection with turbo charging isn’t new. What’s new in the U.S. is the fact that the Buick Regal Turbo combines the features with E85 use. “I think you’ll see more of these, particularly in the smaller displacement engines,” Jones told EPM. “It’s easier to take advantage of it with a small engine.”

Those at the National Ethanol Conference in Phoenix got the chance to test drive the Regal on Feb. 21. Also on hand was the GMC Terrain, also a FFV.

A flex-fuel engine needs a higher flow-rate injector due to the fact that ethanol requires a richer air-fuel mixture than gasoline. Because a flex-fuel engine can have any combination of gasoline and up to 85 percent ethanol in its tank, a sensor in the fuel system measures the current blend. “This allows the engine management system to automatically adjust the mixture to provide improved performance and reduced emissions and fuel consumption,” the company said, adding that the vehicle also has stainless steel fuel lines.  

In contrast to direct injection, port fuel injection fuel is injected into the intake manifold, Jones said. The space that fuel vapor takes up means air can’t get into the cylinder. By injecting fuel directly into the cylinder the mixture is compressed, heated and better evaporated. It increases efficiency by a couple percentages and horsepower by 7 percent. That means increased power output at the same time it cuts back on fuel use and emissions—previously conflicting goals. “This is driving a lot of folks to direct injection,” Jones said.

Adding a turbocharger means more air is pumped into the engine for more power when it is needed. The energy in the hot exhaust gas flow is used to drive a compressor to force air in for on-demand power delivery.

Turbochargers of the past had a problem with lag. “You would hit the gas, it wouldn’t accelerate very well, and then suddenly as the turbine came up it was like somebody lit off the afterburner,” Jones said. “There was this lag and then suddenly it was zoom, and it made the car kind of tricky to drive in traffic.”

This engine, however, has twin-scroll turbochargers that leave lag behind. Instead of increasing air flow by increasing the size of the turbine, and therefore increasing inertia, the engine has two smaller turbines to let the engine generate power and torque even at low engine speeds. "The 2.0-liter Ecotec turbo produces 258 pound-feet of torque from 2,000 to 5,500 rpm making it feel like a much-larger V6 engine while still delivering four-cylinder efficiency," said Ecotec chief engineer Mike Anderson.

Jones puts it this way. “If nobody told you it was a turbo, you wouldn’t know it was a turbo, you would just think it was a very torque-y V6.”