GM preps more fuel efficient engine family for small cars

GM and other automakers are under pressure from consumers and regulators worldwide to hike fuel economy and lower emissions across the board without sacrificing power or performance.

General Motors is creating a family of more fuel efficient small engines that it says will be quieter and more refined than those found in some rival models. The suite of engines will consist of 11 powerplants ranging from a 1.0-liter turbocharged three-cylinder to a 1.5-liter turbocharged inline-four, the company said today.

The three-cylinder engine is notable because rival Ford Motor Co. has been selling a highly regarded three-cylinder engine since fall in the Fiesta subcompact. Ford’s three-cylinder engine also will be available in the 2015 Focus compact.

GM did not disclose how much it expects the new engines to boost the fuel efficiency of its small-vehicle lineup.

Aluminum blocks, heads

GM’s new engines, unveiled today at the company’s sprawling powertrain engineering headquarters north of Detroit, will have aluminum blocks and heads. They are modular, meaning that they can all be built on the same production line.

For instance, the Ford Fiesta with its optional 1.0-liter, three-cylinder engine has an EPA highway rating of 45 mpg, while the Chevrolet Sonic’s EPA highway fuel economy rating is 40 mpg. The new Mitsubishi Mirage, which has a 1.2-liter three-cylinder, has an EPA highway rating of 44 mpg.

Once all of the variants of the new Ecotec engines are in production in five plants around the world, annual volume will be as high as 2.5 million units, GM said. Production has begun on the first new Ecotec engine, a 1.0-liter turbo three-cylinder that debuts this spring in the Opel Adam small car sold in Europe. The redesigned 2015 Chevrolet Cruze that GM will show this year in China gets a new 1.4-liter turbo and a 1.5-liter nonturbo engine.

GM is not saying when it will launch the new Ecotec engines in North America or which vehicles they will power. But Chevrolet’s small cars, which generally lag the fuel economy of key rivals, are likely to be the first to receive the engines.

The engines will be built in Flint, Mich.; Shenyang, China; Szentgotthard, Hungary; Toluca, Mexico; and Changwon, South Korea.

GM isn’t saying how much it is spending on the new Ecotec engines. But the company recently invested $200 million in its Flint plant to tool up for at least one variant.

If GM reaches the production target, the family of engines would represent roughly a quarter of the company’s annual global sales.

High tech

Depending on the market and the application, some engines will be offered with direct fuel injection and turbocharging, which enables small displacement engines to deliver far more power. The engines also will be used in plug-in hybrids, such as the Chevrolet Volt and Cadillac ELR.

With the Pontiac Solstice GXP and Saturn Sky Redline sports cars, GM in 2007 was one of the first automakers to offer turbocharging, direct fuel injection and variable valve timing to boost power. The 2.0-liter engines in those cars were rated at 260 hp.

Ford later used the same suite of technologies branded as EcoBoost. Ford has sold 1.2 million EcoBoost-equipped vehicles since they were launched in 2010. The new Ecotec engines will have:

• Double overhead cams with four valves per cylinder.

• Water-cooled exhaust manifolds that enable faster warm-ups and the car’s heater to deliver warm air quicker.

• Variable oil pumps that save energy by delivering only the amount of oil the engine needs based on speed, load and temperature.

• Piston cooling jets to control piston temperatures.

• Variable valve timing, which adjusts the opening and closing of the intake and exhaust valves and enables the engine to run more efficiently at different speeds.

GM says the new Ecotec engines will offer more refinement than competitive engines from Ford and Volkswagen. The three-cylinder Ecotec, GM says, will be as much as three decibels quieter than Ford’s 1.0-liter three-cylinder.

“From the outset, the noise and vibration requirements for the new Ecotec family were targeted at class leading,” said Randy Guild, noise and vibration engineer for the global Ecotec engines. “Because we started with a clean-sheet design process, every component, from the cylinder block to the fuel injectors played a role in achieving segment-class refinement.”

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