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Mark Cieslak, chief engineer for the 2018 Chevrolet Equinox crossover (image: Lindsay Brooke).

Engineering Chevy's lighter, stronger CUV

Chevrolet’s Equinox has become a serious profit-spinner for General Motors, having moving to second place in the automaker’s global sales behind the Silverado pickup. The vehicle’s increasing success and the launch of the all-new 2018 model come at a time when crossover utility vehicles are smokin’ hot and show no signs of cooling. Everybody wants a CUV, it seems: sales for the booming segment have more than doubled in the eight years since the second-generation Equinox was launched for MY2010. According to AutoTrader analyst Michele Krebs, the segment rose from 10% of the market in 2009 to 15% in 2016. “CUVs have become the new station wagon for families,” Krebs noted.

Last fall, Chevrolet unveiled the 2018 Equinox at Chicago’s Museum of Science and Industry, practically underneath the nose of a World War II German Stuka dive bomber hanging in the museum’s aircraft hall. The type of plane had nothing to do with the projected sales of the new CUV, of course, but we put Chief Engineer Mark Cieslak (who shares his CE duties with the Equinox’s GMC Terrain cousin) under the gun for a few questions.

Chevy is claiming a 400-pound mass reduction for the new Equinox base model versus the incumbent model. How did you achieve such a significant weight-loss?

That weight-reduction is real. It was accomplished in a combination of ways. First, the vehicle is 4.7 in shorter overall that the previous model and the wheelbase is reduced by 5.2 in. It’s also about an inch shorter in height and about on par [0.1 in wider] in terms of overall width. So, we lost a big slice of that 400-pound total by making the vehicle more right-sized and compact, which is what the customer wanted. And the move to two turbocharged four-cylinder engines, the 1.5-L and 2.0-L gas, replacing the old 2.4-L naturally aspirated engine, also helped our mass targets. We’re also using an aluminum hood.

Greater use of high-strength steel alloys in this version?

The body is much stiffer. We upped the amount of advanced high-strength steel, the dual-phase (800 megapascal alloy) and multi-phase steels from 12% to 31%, a big increase. Use of ultra-high-strength material, the martensite press-hardened stuff, went up a little, to about 11%. That’s in the A- and B-pillars. We also have it in a reinforcement near the front foot-boxes to prevent the engine intruding into the passenger compartment in a frontal crash. The front rails have a new geometry for improved offset-impact absorption.

What else? We removed the rear-seat adjustment mechanism, which was pretty heavy, and we’ve significantly increased the total number of spot-welds and feet of structural adhesives in the body. And we’re using an aluminum hood.

Occupant safety was a real focus of our development team. I’ve seen programs actually add mass into a structure, into the chassis, in order to achieve a crash-pulse target. That’s not what we do, it’s not good engineering! It was almost painful but I had to tell the team that adding in mass was not an option on this program. We were going to make it lighter, stronger and more safe.

This car is underpinned by the GM D2U architecture that’s also used on the Buick Envision, is that correct? It was previously on the Theta platform?

In modified form [of D2U], yes. And yes, the new platform helped us get the cowl lower for better frontal visibility.

What else is new about the driveline?

The 2.0-L and the 1.6-L turbodiesel get our new 9-speed transaxle. All-wheel-drive models have a disconnecting rear drive axle for fuel efficiency.

Who supplies the Equinox’s new disconnecting rear-axle set-up?

That’s the American Axle system called EcoTrac.

The 2.0-L seems about right for a CUV this size. How do the 1.5-L and diesel drive?

You won’t believe how strong that one-point-five liter engine pulls! When you get a chance to drive it I want you to let me know. You’ll love it. And the diesel is known as the “whisper diesel” in Germany, it’s so quiet. We’ve got a powertrain for every customer in Equinox.

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