Quote:
Originally Posted by jeff88
Are you saying this scenario could potentially turn your engine into a thermal lance? What if we used ceramic, would that resolve that issue (take the iron out of that equation)?
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If you would try this in an unmodified and otherwise normally aspirated engine, yes there is the risk (or near certainty) of a total meltdown. Ceramics would help - need to be able to take the heat though.
Quote:
Originally Posted by jeff88
Lean burn means more efficient engine, right? How would oxygen end up being unused and how would it be a risk, explosion? How would pumping losses occur if the oxygen is DI? Obviously, there is an issue with exhaust still.
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Direct injection is the way to go, and quite handy if it is stored under high pressure anyway. No pumping losses, no need for the first half of the Otto cycle at all. Just inject at the end of the exhaust stroke, and it will immediateliy ignite and start the next work stroke.
If you precisey match oxygen and fuel you will not get perfect combustion. Some of the oxygen will remain and some of the fuel will be unburnt or halfburnt (carbon monoxide), like in a normally aspirated engine. The cat will burn the last of the fuel with the scraps of oxygen.
Lean burn means adding slightly more oxygen, so all the fuel gets burned while obviously some oxygen remains. Since there is no nitrogen there are no nitrogen oxides in the exhaust gas, and because of the total burn there is no carbon monoxide. You would not need a cat and still have clean exhaust gas. The exhaust will have to be rust prrof though, as the hot oxygen remains would be all too happy to bond with any free metal.
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