Quote:
Originally Posted by poomanchu
Also you achieve 36/1 af under load? Where I come from that means detonation and you needing a new motor.
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At some point, you lean out the mixture so much that you end up lowering the combustion temperature so that detonation is no longer a problem. But, at this point your fuel charge is so diluted that you run into ignition problems because there isn't enough fuel to properly propagate the flame through the cylinder. This is why lean burn engines have specially designed heads or pistons or both, to increase swirl within the cylinder and more evenly disperse the fuel through the cylinder.
Here is a graph that represents things well. We know NOx is created at high cylinder temperatures. As you continue to lean things out, the temperature starts to go back down. However, as you continue, hydrocarbons increase as the fuel isn't completely burning anymore.
