Engineers charge toward 42V

The classic 14V electrical systems that have powered cars for more than 40 years will soon be seen only in museums or junk yards.

Replacing them will be 42V systems that promise up to 10% better fuel economy while enabling a host of advances to improve safety, performance, handling, and vehicle packaging. Among those advances: brake-by-wire, steer-by-wire, electromagnetic valve control, and integrated starter generators.

As early as next year, automakers such as Opel, Mercedes, and Renault could incorporate full 42V systems in some of their luxury cars. It's no coincidence that the pioneers all carry European nameplates: They hail from a continent with high gas prices and stringent pollution requirements. These 42V electrical systems may help them control those dual problems while reinforcing their reputation for supplying cars that handle well.

The trend is bound to spread. Indeed, research firm DRI-WEFA predicts that 35% of light vehicles produced in North America, Europe, and Japan will have 42V electrical systems by 2010.

But first, engineers will have to grapple with several technical issues involving durability and performance of components of 42V systems. Everything from light bulbs to integrated circuits will change. There are also the psychological issues: After all, in a business where poor quality and performance can lead to expensive recalls, no one wants to rush headlong away from technology that, like traditional 14V battery systems, has proven itself over a generation.

On the following pages, Design News editors describe the background behind the 42V movement, some of the engineering trends and issues involved, and one major fuel-efficiency and emission-reducing technology 42V could make possible.