To the elation of GMC and Chevrolet truck and 4×4
enthusiasts across the internet, the new breed of GM trucks and utility
vehicles is readying for a sales launch later this year.
Tony DiSalle, vice president of GMC Marketing, says “these
trucks have all the power and capability that’s expected in today’s market,
excellent fuel efficiency, plus a lot of unexpected, purposeful features
developed with truck owners in mind.”
The new GMC Sierra, Chevrolet Silverado, and associated SUV
variants (Tahoe/Yukon/Suburban) will soon hit dealers in a variety of models
and trim levels that pack new features, new styling, new safety implements and
new technologies.
They’ll also pack an all-new engine lineup, which consists
of a 5.3L V8, a 6.2L V8 and a 4.3L V6. Displacements are the same as the last
generation trucks, but GM officials say the engines only share a ‘handful’ of
parts with the outgoing power units.
Dubbed ‘Ecotec 3’, the new family of GM truck engines
promises plenty of durability, as well as some of the latest fuel-saving
technologies included as standard.
Here’s a closer look at how GM says the Ecotec 3 powerplant
range works hard to extract more clicks from every litre.
Active Fuel Management: When full performance isn’t
required, the Ecotec 3 engines can turn off cylinders selectively, reducing the
engine’s need for fuel.
Unless you’re driving a Smart Fortwo, sustained cruising
down the highway requires only a fraction of the engine’s available power. In
this situation, Ecotec 3 engines ‘turn off’ half of their cylinders while
nobody’s looking, to help cut down on needless drinking.
How’s it work? Advanced engine controls cancel fuel
injection to these cylinders, and a hydraulic valve control mechanism keeps the
intake and exhaust valves on the deactivated cylinders closed. In this
situation, gases in the deactivated cylinders are compressed over and over
again, resulting in a ‘gas spring’ effect that helps the four running cylinders
operate more easily.
The entire system is computer controlled, and actuated by
solenoids and oil pressure. It’s invisible to the driver, other than a small
display in the instrument cluster that references the engagement of
four-cylinder mode.
“We chose to keep the proven capability of our larger V8
truck engines, and save fuel by switching off half of the cylinders when they
aren’t needed” said Jordan Lee, global chief engineer for small block engines.
He goes on to further diss Ford.
“Rather than adapting a V6 intended for use in passenger
cars, we built a new engine from the ground up based on the unique demands of a
truck. Sierra’s 4.3L engine shares its basic design architecture with the
latest iterations of the V8 engines that GMC owners have trusted for
generations”.
Interestingly, GM officials say their AFM technology allowed
them to stay away from a smaller-displacement, turbocharged engine (a la Ford
Ecoboost) for long-term durability. Drivers will also benefit from a proper
exhaust note at full throttle, which is not a characteristic of the Ecoboost
mill from Ford.
Article Credit: www.autos.ca
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