Detroit — Ford today unveiled its popular, restyled 2011 Edge Crossover at the Chicago Auto Show with a freshened exterior and interior, upgraded “Sync” connectivity system, and . . . a four-cylinder Ecoboost engine?

Why would an SUV, already the heaviest in its class (tipping the scales at over 4,000 pounds — a full 200 pounds heavier than the Toyota Venza), add a 230-HP four-banger to its standard 300-HP V-6 lineup? The four-cylinder engine is more typically used in its much lighter sibling, the Ford Escape. It’s an engine that auto analysts say is not up to the task. And more important, it’s an engine consumers won’t want. So: why?

Because Washington wants it.

“The problem with the Edge is that it’s porky,” analyst Jim Hall of 2953 Analytics tells the Detroit News. “But in light of the new CAFE standards, it’s probably a good idea.” That is, with Congress mandating 35 mpg average fuel economy for all vehicles by 2015, Ford is throwing in the more fuel-efficient option to trick the numbers.

Traditionally, CAFE standards were based on the average mpg of cars sold. But since customers didn’t always buy what the government thought they should, allowances — “credits” — were given for alternative-fuel vehicles and other unpopular models. Under the new, ridiculous 35 mpg standard (the mileage a Smart car gets), those credits have reached epidemic proportions. Manufacturers will get credits for 100-mpg electric vehicles like the Volt, but they willl also need them for offering options in SUVs like the Edge.

This means more expense for the industry (some of which the taxpayers are footing with Energy Department loans). But it also means cynical governance — because the standards are meaningless. They are just numbers to be gamed.

Our cynical pols want credit for a fuel economy revolution — whether it’s revolutionary or not.