2/27/2012 | 3 MINUTE READ

GM Develops New Small Engine Family

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GM is developing a new family of small-displacement Ecotec gasoline engines to provide better fuel economy and performance.


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Jim Federico, vehicle line executive for General Motors’ global compact, small, and mini cars and electric vehicles—having just gotten off the Global Epsilon platform (which meant he worked on projects like the current Buick Regal)—spends a good bit of his time traveling to Korea, China, and Germany. Consequently, when he says, “Our customers around the world agree we need to reduce our dependence on petroleum and reduce vehicle carbon emissions,” it isn’t something based on a report he read. He’s been there and continues to go there.

“We are working aggressively on vehicle electrification and other technologies”—within a few minutes of making this statement, he announces that Chevrolet will begin production of the Spark EV that will use nanophospate lithium ion batteries from A123; the car will be available in selected locales including the U.S. in 2013—“but the most immediate progress will come from continually improving the internal combustion engine.”

So to that end, he announced that they are developing a new family of small-displacement Ecotec gasoline engines to provide better fuel economy and performance.

The engines, which will range in size from 1- to 1.5-liter and which will be both three- and four-cylinder configurations (the existing Ecotec engines—1.4-, 2.0-, 2.2-, 2.4-, and 2.5-liter—are all fours), will go into production mid-decade at various global sites. The program is projected to necessitate the production of two million engines per year by the end of the decade.

The engines are being developed by GM, Shanghai Automotive Industry Corp. (SAIC), Shanghai General Motors, and the Pan Asia Technical Automotive Center (PATAC).

While Federico is keeping the specifics close to his vest, he does say:

•    The engines will be capable of running on alternative fuels. “Everything but diesel.”
•    They’ll be using direct injection and turbocharging
•    The engines have a modular design to facilitate flexible manufacturing. This modularity also facilitates the use of components from one size engine to another.
•    The engines will be tuned to the application: “the sweet spot of horsepower and torque will be achieved for every application.”
•    The engines will “cover A-, B-, C-, and possibly D-segment vehicles.” So for certain, most of his portfolio will be covered. Federico points out that on a global basis, over 60% of what GM sells is a compact or smaller car.
•    The new family will replace three existing engine families (e.g., in the U.S. the Ecotec families are the 1.4-liter, the 1.8-liter, the 2.0- and 2.4-liter, and the 2.5-liter engines).



One of the things addressed for the new 2.5-liter engine that will be offered in the 2013 Malibu is how it sounds, particularly during acceleration, as the rpms rise. So the engineers audibly “tuned” the engine. Explains Tom Slopsema, Noise and Vibration engineer, “Think of it as the difference between low-frequency, course noise, such as a vacuum cleaner, versus a higher frequency, precision noise, such as a sewing machine. We focused on reducing the overall engine noise level and placing the remaining noise in a higher frequency range.” The elements addressed to make the Ecotec 2.5 sound better and vibrate less: Relocated Balance Shafts: Located in a cassette in the oil pan; one benefit is that it shortens the drive chain; In-Pan Oil Pump Assembly: No longer in the front of the crankshaft; reduces noise in the front cover area; Camshaft Drive with Inverted Tooth Chain: Uses a premium, inverted-tooth design rather than a conventional roller-type chain; provides smoother meshing of the chain links to the sprocket teeth; Two-Piece Oil Pan: Features an aluminum upper section and a stamped steel lower section; the upper is light and supports the engine’s structure while the lower provides a better sound performance; Structural Camshaft Cover: Cast-aluminum part features increased ribbing and additional attachment bolts down the center; it is stiff and provides oil sealing for valvetrain oil control passages integrated within the cover; Acoustic Intake Manifold Cover: Composite plastic intake is wrapped with a clamshell-like cover; isolates the intake to reduce noise and provides a clean exterior appearance; Forged Steel Crankshaft: Stronger and more durable than conventional cast iron; reduces noise and vibration at mid- and high rpm levels; Iron Main Bearing Cap Inserts: The iron inserts cast into the aluminum block bedplate add to the structure of the main bearings; results in greater smoothness and quietness; Isolated Fuel Rail: The high-pressure fuel system for the direct injection can be noisy; the injectors are suspended and the fuel rail is mounted to the cylinder head with rubber components; Structural Front Cover: Similar configuration to the structural camshaft cover; this covers the camshaft drive system and the balancer drive system.