Exhaust from a car's tailpipe is usually considered a bad thing. But exhaust is also used to make engines burn cleaner. In this episode of SAE Eye on Engineering, Senior Editor Lindsay Brooke looks at a technology called Exhaust Gas Recirculation (EGR) and its environmental benefits. SAE Eye on Engineering can be viewed at https://youtu.be/jtGr4RFm9Qg. It also airs in audio-only form Monday mornings on WJR 760 AM Detroit's Paul W. Smith Show. Access archived episodes of SAE Eye on Engineering at www.sae.org/magazines/podcasts.