Small engines big in GM's future

New Ecotec three- and four-cylinder engines to be used in one of every four GM vehicles

Published: April 7, 2014, 5:00 PM

The small-block V-8's headlining role in General Motors' engine hierarchy is about to be threatened by an all-new family of Ecotec engines at the extreme opposite end of the size scale.

Those engines, in three- and four-cylinder configurations and 1.0- to 1.5-litre displacements, are destined to power one of every four GM vehicles sold worldwide by 2017.

By then, GM expects to build more than 2.5 million of the new engines annually in at least five manufacturing locations around the world.

Eleven different variations of the engine will find application in five brands and 27 models.

Prominent among them will be the next-generation Chevrolet Cruze, which will make its world debut in Chinese-market guise at the Beijing Motor show, later this month.

The new engines will have power outputs from 75 horsepower, in normally-aspirated, three-cylinder form, to 165 horsepower in 1.4-litre turbo form. Torque output will range from 70 to 184 lb-ft.

The architecture is also designed to support hybrid propulsion systems and alternative fuels, including ethanol (for the Brazilian market).

GM's big focus on small engines is consistent with other manufacturers' response to a global need for reduced fuel consumption and associated carbon dioxide (CO2) emissions – driven by legislation in many jurisdictions.

Reducing engine size, along with vehicle weight, is one of the few ways left to make big strides toward that goal.

In developing the new engine family, GM's has already downsized some existing engines but in this case its engineers were given the chance to start from scratch.

The GM engineers' brief was to provide customers with segment-leading efficiency, refinement and durability, while at the same time reducing manufacturing complexity and maximizing use of common components.

Plus, of course, to achieve all these goals while maintaining the levels of performance that customers have come to expect

Accordingly, the new engines incorporate such in-vogue technologies as aluminum cylinder blocks and heads, central direct fuel injection, continuously variable valve timing, variable intake manifold airflow and exhaust manifolds integrated with the cylinder head, as well as turbocharging in some applications.

The engine blocks all share the same bore spacing, bore diameter and other dimensions to help reduce complexity, and cost, while allowing the flexibility to quickly adapt the architecture for new applications.

Other shared bits include some rotating parts as well as fuel- and valvetrain-system components and engine-driven accessories.

GM also touts such attributes as the engines' quietness relative to that of their direct competitors – as much 50 percent quieter than Volkswagen’s 1.4L four-cylinder and up to 25 percent quieter than Ford’s 1.0L turbo three-cylinder.

To my ear, recordings of the various engines at idle and at full song seemed to validate those claims.

According to Canadian-born Kendell Fulton, assistant chief engineer on the project, the engines are also capable of cold-starting at -40C without aids, such as block heaters.

The first production applications for the new Ecotec engines will be in an Opel Adam in Europe (1.0L turbocharged three-cylinder) and the next-generation 2015 Chevrolet Cruze in China (1.4L turbocharged and 1.5L naturally aspirated four-cylinders).