If you want to know more than one thing, you need more than one sensor. In fact, many engines today have not just two oxygen sensors, but four.
The Daily Galaxy on MSN
Forget lithium batteries: Scientists built a dirt-powered fuel cell that runs forever
A sensor buried in a farm field has two ways to stay powered. A battery that will die. Or a solar panel that will get caked ...
Some results have been hidden because they may be inaccessible to you
Show inaccessible results