From left, 1.4-liter turbo, 1.5-liter DI, 1.0-liter turbo

One in four GM vehicles produced worldwide will eventually be powered by a new line of Ecotec engines that were introduced today during a technical presentation for the media in Detroit. Officials said that by 2017, more than 2.5 million new Ecotec engines will be assembled annually at five different plants worldwide, and those units will be used in many of the company’s highest-volume small cars and crossovers throughout five brands and 27 models.

The new family will include 11 engines with 3- and 4-cylinder variants ranging from 1.0-liter up to 1.5-liter. Some will be direct-injected turbocharged with others will have flex-fuel capability — including ethanol, CNG and LPG. Base model engines will be port-fuel injected (PFI). Horsepower will range from 75 up to 165 with peak torque output ranging from 70 lb-ft up to 184 lb-ft. All are designed to meet stricter emissions and fuel economy requirements around the world.

“The new Ecotec architecture represents the most advanced and efficient family small-car gas engines in GM’s history,” says Tom Sutter, the company’s global chief engineer. “Each variant is designed for a specific application or local market, but all share design, performance and refinement traits that make the new architecture one of the most adaptable in the industry.”

A versatile modular strategy is behind the new architecture with a common bore center of 81mm (3.19 inch) and a standard bore size of 74mm (2.91 inch). The blocks also have a standard deck height that will accommodate a variety of crankshaft strokes. Most of the 3-cylinder engines will be built with a 1.0-liter displacement (77.4mm or 3.0-inch stroke), but there will also be a 1.1-liter model for select markets. The 4-cylinder offerings include a 1.4-liter (81mm/3.2-inch stroke) and 1.5-liter (86.6mm/3.4-inch). All turbo and DI engines will have forged steel cranks with the PFI engines sporting cast-iron cranks that are lightened with hollow cores in the main and rod journals. Connecting rods are powder-metal steel.

The 4-cylinder currently offers the most flexibility with 1.4-liter DI turbo models to support gas, CNG and E100 fuels. There’s also a 1.4-liter PFI version. The 1.5-liter model will be offered in DI and DI turbo versions. The 1.0-liter 3-cylinder gets PFI, DI turbo and LPG versions while the 1.1-liter will be offered only in PFI. GM says there will be a hybrid variant of the new Ecotec family but did not release any details on the size or power. Officials stressed that diesel options are not in the plans for this family.

The engines feature all-aluminum construction with a 2-piece style open-deck block that is supported with a bedplate housing the lower main caps. The block is also cast with iron liners in place. The cast-aluminum oil pan is strengthened with a steel sump that also contributes to noise reduction. The variable-displacement oil pump is chain driven and is located inside the pan. The flow volume of the oil pump is designed to support the oiling requirements for camshaft phasing and piston cooling as spray jets are mounted at the bottom of each cylinder. Bay-to-bay breathing to reduce windage in the crankcase is enabled through holes cast in the top of the bulkheads and through passages cast where the block and bedplate meet. Additionally, the 1.0-liter variant features a balance shaft mounted inside the oil pan to quell the unique vibration characteristics of a 3-cylinder arrangement.

Extensive combustion analysis was needed to optimize cylinder head and piston designs. Direct-injected variants combine a sculpted piston design with a comparatively small combustion chamber in the head to support the high-compression, which goes up to 12.5:1 on some engines. Turbocharged engines will run at 10:1 on regular unleaded fuel.

“This is where we started the program,” adds Sutter, noting that the intake port geometry was designed to enhance tumble into the cylinder and promote a more homogeneous mixture.

The modeling also helped determine the optimal 6-degree angle for the 6-hole DI fuel injectors. A cylinder head mounted pump supplies fuel to the injectors at up to 2,900 psi (20 MPa). The pump is driven by a 3-lobe cam on 3-cylinder engines and a 4-lobe cam on 4-cylinder engines.The engine-mounted fuel pump also uses dedicated control algorithms developed for the on/off control valve, enabling greater control of the valve needle at low speeds and low rpm.

Turbos are all the rage in small engines, so the cylinder head was designed with an integrated exhaust manifold to get the spent gasses to the turbo quicker. The system uses a comparatively small, low-inertia water-cooled, single-stage, single-scroll turbocharger that’s mated with an intercooler and pressure-activated wastegate. The diameter of the turbine wheel is only 35 mm, while the low-hiss compressor measures only 40 mm in diameter to help the engine deliver 90 percent of maximum torque at only 1,500 rpm for the 1.4L variant. Combined with the high-tumble ports and other combustion optimization, officials say there is less need for spark retard at maximum boost pressure to avoid detonation.

On select naturally aspirated variants, the Ecotec will boast a 2-stage variable intake manifold. At engine speeds below 5,000 rpm – at full load – inlet air passes through intake tracts that increase torque. At speeds greater than 5,000 rpm, a butterfly valve within the lightweight composite intake manifold opens to create a shorter intake path, enabling the engine to produce more horsepower. Approximately 90 percent of peak torque is available from 2,200 rpm to 6,000 rpm with this manifold.

All engines run dual overhead cams operating four valves per cylinder with low-friction hydraulic roller finger followers. The cams are hollow in some sections to save weight and are driven by a timing chain with automatic hydraulic tensioning. The aluminum cam phasers have a “total authority” of more than 60 degrees to optimize valve timing under different load conditions. A hard-mounted aluminum cam cover features an integrated oil separation system, which serves as the main body for the engine positive crankcase ventilation system – which contributes to optimal combustion control. Passages integrated in the cylinder block and cylinder head enable flow of blow-by gases from the crankcase into the oil separation chamber, as well as drainage of the separated oil back to the crankcase. The cam cover assembly also incorporates the oil-control valves for the cam phasers and camshaft position sensors.

GM built 1,600 prototype and experimental engines during the Ecotec development and logged more than 2 million miles of validation tests. Some 270 engines were run through endurance tests that  four weeks of wide-open-throttle operation.

The first application for the new Ecotec family will be a 1.0-liter turbo 3-cylinder model for the Opel Adam in Europe followed by 1.4-liter turbo and 1.5-liter N/A 4-cylinder engines in the next-generation Chevy Cruze in China. GM officials are mum on the first application for the US market.