The EPA has set standards for diesel trucks to use technology that can eliminate up to 80 percent of the nitrogen oxide (NOx) green house gas emissions.
Selective catalyst reduction (SCR) injects a small amount of NOx reducing agent into the exhaust ahead of the catalyst. For the first time, the EPA has outlined how SCR should be installed in diesel trucks. SCR has been used previously in industrial applications, as well as in DaimlerChrylser's E320 Bluetec sedan. Mitsubishi has alsolicensed SCR technology from Nissan Diesel for its trucks.
One limitation is that the reducing agent must be refilled periodically(during standard maintenance) or else the NOx could actually increase. The EPA is considering warning systems to alert drivers to low amounts of reducing agent as well as methods that would prevent the vehicle from either being restarted or refueled once the agent is emptied. Heartland.org is spreading some FUD about the proposal.
Change can be hard, but reducing most of the NOx from long haulers (as well as diesel passenger cars) seems worth the additional effort.
Source: EPA
