Buick: the only domestic brand powered exclusively by direct injected engines
Fact is, direct fuel injection has enabled fuel economy improvements of up to 3 percent on the Buick Enclave, LaCrosse, Regal and the upcoming Verano – without sacrificing performance and still meeting the world’s most-stringent emissions requirements.
Over the past three decades, fuel delivery systems have evolved from the relatively primitive carburetor that relied on the Bernoulli effect to draw fuel through a tiny jet as air accelerated by, to the more-precise throttle body injection that gave way to port and finally direct injection.
For the record, this writer started his design career at Holley Carburetor right after Colt Industries took over the company. I well remember the Bernoulli principle in the venturi area, with a profile much like an airfoil of an airplane wing. At that time, only a few American cars had manifold injection, like the 1963 Corvette.
Today’s high-pressure direct injectors deliver fuel to right the point of combustion in the cylinder so fuel doesn’t get left behind on manifold walls or evaporate up out of a carburetor.
The demise of the carburetor ended problems like flooding and vapor lock. Now, direct injection brings several benefits over the more recent sequential port fuel injection systems.
“Spraying fuel directly into the combustion chamber reduces the temperature of the compressed mixture as the fuel evaporates, which enables a higher-compression ratio, allows for more spark advance, and reduces fuel consumption” said Anderson. “The beefier low-end torque and improved drivability of the direct-injected 2.0L turbo makes it a no compromise high-efficiency substitute for a bigger and heavier V6.”
Engines with direct injection also warm up faster thanks to the ability to add a second injection pulse right before the spark plug ignites the fuel following a cold start. This faster warm up can cut emissions of unburned hydrocarbons by up to 25 percent.
With direct injection, the 220 horsepower Buick Regal Turbo beat the Acura TSX by 19 hp and 88 pound-feet of torque from just 2,000 rpm while still achieving up to 32 mpg on the highway, an advantage of 4 mpg.
On the other hand, the Buick Enclave is the most fuel efficient eight-passenger crossover on the market with an EPA estimated 17 mpg city and 24 mpg highway.
Torque News Assessment
It was disconcerting at last year’s SAE World congress when GM engineers could not answer my question as to why all the new engines at GM did not have direct injection. They acted like they did not know.
Now it’s nice to see at least Buick is taking direct fuel injection serious enough to make it across the board.
Of course, I have to ask the next set of questions: When will the rest of GM go this route for all of its car lines? Likewise, when will GM invoke dual fuel beyond ethanol and use natural gas?
An then the final question: When will GM wake up and stop doing incremental improvements when it knows America needs a quantum leap? By that I mean going to an engine design that makes the leap towards maximizing the efficiency of the internal combustion engine. I’m talking 50 mpg minimum here for the city, not just the highway.
Fact is, the only technological step left for the IC Engine is splitting the four cycles into a cold and hot side. And the mandated mileage requirements of 2016 are just around the corner.
For sure the Volt technology is too expensive for the masses. And if you don’t believe that, then ask yourself why less than 2,500 Chevy Volts have been sold; and the Nissan Leaf has not faired any better.
[Image Source: media.gm.com]
About the Reporter: After 39 years in the auto industry as a design engineer, Frank Sherosky now trades stocks, futures and writes articles, books and ebooks like, "Perfecting Corporate Character," "Awaken Your Speculator Mind", and "Millennial World Order" via authorfrank.com. He may be contacted here by email: [email protected]
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