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Old 05-22-2020, 04:27 PM   #23 (permalink)
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lack of heat is the issue.

Originally Posted by rmay635703 View Post
The cat should burn off the hc and co using the excess NOx
The catalytic reaction needs a minimum heat/energy level. Without this, the reaction is either too slow or non-existent. We can program the engine run regimes to oscillate between lean-burn and stoichiometric to keep the catalysts hot enough to function.

Also, if you want to use the oxidation potential of NOx to convert the growth in HC and CO in ultra-lean mixtures, you will not have enough to complete the reaction equation. Look at the original graph - there is exceedingly small amounts of NOx the further lean you operate.

The trick to running ultra - lean is in reducing the COV and reducing the quench thickness. This gives you more power to use and reduces HC and CO respectively.
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