[me and my metro]

The way I understand it is: it is all about controlling NOx emissions. There are two schools of thought, the first is lots of egr to cool the charge. The problem with lots of egr is lots of soot, so you have to trap it and burn it with the cat and extra fuel. The second is not so much egr which makes more NOx but less soot, then kill the NOx with urea. I know International is having trouble meeting the new standards even with urea. I was told our new Internationals will come with Cummins engines because they can meet smog.