NEW ECOTEC 2.4-LITER ENGINE DELIVERS CLASS-LEADING TORQUE, SOPHISTICATED DRIVING APPEAL
PONTIAC, Mich. – GM Powertrain’s new Ecotec 2.4-liter four-cylinder engine, launching in the all-new 2005 Chevrolet Cobalt, slightly modifies that well-used adage, “There’s no substitute for cubic inches.”
In the case of this slightly larger version of the original Ecotec 2.2-liter, one of GM’s highest-volume engine families, there are a few more cubic inches found in the new 2.4-liter variant. But along with the larger displacement, which has become vital in the increasingly competitive compact-car segment, the 2.4-liter for the first time brings variable valve timing to the Ecotec modular engine family.
“We have added technology to improve low-end torque and continue to reduce emissions,” said Jay Subhedar, Ecotec global four-cylinder engine assistant chief engineer. “For the new Ecotec, variable valve timing helps deliver 90 percent of the torque peak at as low as 2400 rpm. That sort of responsiveness enormously enhances engine response.”
The combination of slightly more displacement and variable valve timing enables the Ecotec 2.4-liter to achieve one of the highest torque ratings – an estimated 170 lb.-ft. – for a 2.4-liter normally aspirated four-cylinder in the United States And the Ecotec 2.4-liter’s 170 horsepower at 6000 rpm also is one of the highest specific-power outputs for any non-boosted four-cylinder of any size sold in the U.S., according to Ward’s 2003 market data.
The new Ecotec 2.4-liter engine’s torque-rich power delivery and its designed-in refinement deliver a driving experience that will please both performance-oriented buyers and those simply seeking a more sophisticated feel from a compact-car powertrain.
Intelligent technology as important as cubic inches
Increasing displacement is perhaps the most-proven technique to
improve horsepower and torque, and that’s where GM Powertrain
engineers started when developing the Ecotec 2.4-liter.
For the new 2.4-liter variant, both cylinder bore and stroke are increased in relation to the original Ecotec 2.2-liter engine. The new engine’s bore is 88 mm and stroke is 98 mm, versus the 2.2-liter’s 86-mm bore and 94.6-mm stroke. These increases, multiplied by each of the Ecotec 2.4-liter’s four cylinders, yield a total displacement of 2,384 cubic centimeters versus the original 2.2-liter’s 2,189 cubic centimeters.
But equally important to delivering class-leading torque is the Ecotec 2.4-liter’s new variable valve timing system, developed to enhance the low- and midrange torque output of the new engine.
The new variable valve timing system uses electronically controlled hydraulic camshaft phasers to alter the relationship of the intake and exhaust camshafts as much as 50 degrees relative to the crankshaft. Yet the system adds little weight or assembly complexity to the basic Ecotec DOHC architecture because the Ecotec family was designed from the beginning to easily accept technology advances such as variable camshaft phasing.
But the new Ecotec 2.4-liter’s technology story hardly stops there. The new Ecotec enjoys a host of new technical enhancements:
Ecotec’s robust design, structure enhanced for
new 2.4-liter variant
Along with significant new technology additions, the new Ecotec
2.4-liter enjoys numerous upgrades to the robust basic Ecotec
engine architecture. The Ecotec design, already noted for impressively
low levels of noise and vibration, includes features like a structural
oil pan; full-circle transmission mounting flange; a highly rigid
lower crankcase with four-bolts at each bulkhead; long cylinder-head
bolts to assure robust clamping of the cylinder head to the engine
block; and direct-mounted accessories to eliminate these traditionally
large contributors to engine noise, vibration and harshness.
The Ecotec 2.4-liter’s basic structure has been enhanced in several significant ways to ensure the engine’s increased displacement and power do not compromise the Ecotec’s high levels of inherent refinement.
“In the global engine family, we look at various engine components to evaluate which are the right ‘fit’ for any given engine application,” said Subhedar. “Commonality is a vital part of the Ecotec program – it’s like an interlocking puzzle. We try to choose the best combination of components from the myriad of available technologies.”
Thus the Ecotec 2.4-liter leverages several heavy-duty components and systems borrowed from the high-performance Ecotec supercharged 2.0-liter engine program, plus many that are unique to the new 2.4-liter variant:
The Ecotec 2.4-liter will be built at GM Powertrain’s Spring Hill, Tenn., assembly facility.
GM Powertrain is a global producer of engines, transmissions, castings and components for GM vehicles and other automotive, marine, and industrial OEMs. Headquartered in Pontiac, GM Powertrain has operating and coordinating responsibility for General Motors powertrain manufacturing plants and engineering centers in North America, South America, Europe, and the Asia-Pacific region.
General Motors Corp. (NYSE: GM), the world's largest vehicle manufacturer, employs 342,000 people globally in its core automotive business and subsidiaries. Founded in 1908, GM has been the global automotive sales leader since 1931. GM today has manufacturing operations in 32 countries and its vehicles are sold in more than 190 countries. In 2002, GM sold more than 8.6 million cars and trucks, nearly 15 percent of the global vehicle market. GM's global headquarters is at the GM Renaissance Center in Detroit. More information on GM and its products can be found on the company's consumer web site at www.gm.com.