DETROIT

UNDER the shapely sheet metal and ultraglossy finishes of the vehicles introduced at the auto show here were technical details just as captivating as the visual attractions. The advances ranged from minor interior convenience features to entirely new approaches in structural design.

Given tightening fuel-economy standards and shifting buyer preferences, it was no surprise that automakers brought more electrics and hybrids to the show, and this year there seems to be a growing recognition that plug-in hybrids are a logical transition to wider acceptance of battery-powered vehicles.

Still, the move is gradual, and the industry displayed a philosophy that might be best described as less of this and more of that: less displacement in conventional engines and more power per liter; more miles per gallon and less power-robbing friction; less weight and more transmission ratios to keep engines running in their sweet spot.

Here is a look at some emerging engineering trends at the show:

LIGHTWEIGHT LUXURY Like Mercedes-Benz SL sports cars of the past, the 2013 SL550 showcases the automaker’s technical prowess. Among its innovations is a body that is almost entirely aluminum — and 308 pounds lighter than that of the previous model. Numerous forming techniques and welding technologies are employed in creating the structure. Gunter Fischer, program manager for the SL-Class, said the body, which was seven years in development, sets a benchmark for torsional rigidity among roadsters.