To earn the EPA's rare 50-plus highway fuel economy rating for the 2018 Cruze diesel sedan, Chevrolet engineers didn't just drop a fuel-efficient engine and transmission into the Cruze and call it done.
"There is no one silver bullet," says Craig Weddle, Cruze chief engineer. "There were a lot of little things we had to do to make it all add up."
It was a significant technical feat.
Last week when the EPA confirmed the Cruze diesel's 52-mpg highway fuel economy rating through its own testing at the agency's Ann Arbor, Mich., labs, the Cruze became one of only four non-hybrid cars to punch through the 50 mpg highway barrier since 1990.
And after the EPA revised its fuel economy test procedures in 2008 to better reflect real-world fuel economy, only one non-hybrid car since 1990 -- the Geo Metro XFi, also sold by Chevrolet -- has retained a 50-plus mpg rating. (The EPA has revoked certification and mileage ratings for all VW diesels affected by the emissions cheating scandal).
"Fuel economy is the reason for purchase, and we were looking for a wow factor," said Dan Nicholson, GM's vice president of Global Propulsion Systems.
The Cruze's results took a total General Motors team effort that drew in aerodynamicists, electricians, powertrain engineers, lightweighting specialists, friction gurus, calibration engineers and others.
The Cruze diesel, on the way to dealers now, even has a chief energy engineer, Eric VanDommelen, whose goal was to make sure every pound-foot of torque sent to the wheels delivered maximum efficiency and that few, if any, electrons were wasted.
Much of the technology used to boost the car's fuel economy, such as the smooth underbody, low-drag brakes and active grille shutters, came straight from hybrid cars.
GM will have its challenges marketing the fuel-sipping diesel. The car is part of a big push at GM to attract Volkswagen buyers leaving the brand in the wake of the diesel emissions cheating scandal there. That won't be easy. Gasoline is cheap and consumers are deserting cars for SUVs, crossovers and trucks. Diesel engines, thanks to VW's controversy, now have image issues.
It's also not a given that VW buyers will consider switching to Chevrolet.
Nicholson said in August that GM would be going after VW's diesel faithful, who once accounted for about 20 percent of the German brand's U.S. sales. A diesel version of the Equinox crossover is also on the way, and by the end of 2018, GM will offer 10 diesel models in North America. Nicholson said last week diesel vehicles represent a growth opportunity for Chevrolet.
But none of that mattered to the engineers who tuned and tweaked and prodded the Cruze diesel until it rolled over the 50-mpg goal line.