GM told Design News that the Cruze's diesel engine solves some of the notable problems that previously constrained diesel popularity in this country. The noise, exhaust soot, and foul smells were engineered out a long time ago.
Still, the cost of a diesel engine is markedly higher than that of a gasoline-burning engine. The engine's block, pistons, crankshaft, and connecting rods must be beefier as a means of dealing with the higher operating pressures necessary for compression ignition. "If you look at a 2.0-liter common base size pistons, you can see that the diesel will cost more," Siegrist told us. "It comes down to the higher cylinder pressures that the whole engine sees."
Moreover, engine control is a significant issue. "European diesels are wonderful engines," David Cole, chairman emeritus of the Center for Automotive Research, told Design News late in 2012. "But they do have a costly problem with nitrogen oxide control because diesel exhaust has a lot of excess oxygen in it. That's tricky and expensive to do."
The fuel itself is also more costly in the US, where it doesn't enjoy the tax advantages provided by European markets. The reason for the higher initial cost is that diesel fuel uses longer-chain hydrocarbons with a relatively low self-ignition temperatures, which are needed for compression ignition.
"Diesel fuel is harder to make," Cole told us. "There are only so many long hydrocarbon chains in a barrel of crude." The result is that diesel fuel typically costs between 25 cents and 40 cents per gallon more than gasoline in the US, he added.
Chevrolet expects buyers of the Cruze diesel to be drawn to it by its performance, however, rather than its pure economic advantages. "The Cruze diesel won't be focused on the pure business case," Siegritz said. "You're getting a premium product -- a more powerful product -- that still gets great fuel efficiency."