locomotive air brake

While I've browsed Google, Yahoo, Bing and Wikipedia, I can not find an answer about why. I've examined those sites of Taylor, Martin, Gibson, Fender and even more manufacturers and they also definitely don't discuss it. I can not even find anybody with a guitar online forum that has speculated about why. The story shocked me more than usual because I know my friend is a fairly good martial artist. He is often dubbed as 'talented' by his colleagues and superiors. What's wrong with this story? In theory, he may have wasted the thief quickly while he clearly had no weapon with him. According to him, he didn't know what to do. He knew how he could subdue such assault but he just did not know how to handle it at that time. The EGR system routes a number of the exhaust gases (6 ? 10%) from the EGR valve, last on the Intake System, and ultimately within the combustion chamber. The exhaust gases are inert i.e. they cannot burn in the combustion chamber; also, the exhaust gases take up a number of the space which would preferably be taken with the intake air. This reduces the volume of intake air readily available for the combustion process during each Power Stroke; which in turn decreases the peak combustion temperatures. This brings about lower NOx emissions.