Chrome exhaust pipe
C/Net reports that General Motors has worked on prototypes for a metal-plated device that fits around a tailpipe to trap waste heat and turn it into electricity.
The principle of thermoelectrics creates the possibility of power from heat, and GM is working with researchers at Ohio State University to try to capture the exhaust heat and turn it into power. The heat sink could eventually lead to a 5-percent increase in fuel economy, which could mean an extra mile per gallon in a vehicle like the Chevrolet Suburban.
The tech Web site adds the gains could be even more dramatic in smaller, more fuel-efficient vehicles. Some 30 to 40 percent of the heat generated during combustion is used by the vehicle, with the rest lost to inefficiency or to cooling.