| CPC F01N 3/208 (2013.01) [B01D 53/9431 (2013.01); B01D 53/9477 (2013.01); B01D 53/9495 (2013.01); F01N 3/106 (2013.01); F01N 3/2803 (2013.01); F01N 3/2892 (2013.01); B01D 2251/2062 (2013.01); B01D 2255/102 (2013.01); B01D 2255/904 (2013.01); F01N 2370/02 (2013.01); F01N 2610/03 (2013.01); F01N 2610/05 (2013.01); F01N 2900/1402 (2013.01)] | 20 Claims |

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1. An internal combustion engine system, comprising:
an internal combustion engine configured to combust a first fuel and a second fuel, wherein a portion of an exhaust of the combustion engine comprises nitrogen dioxide (NO2) and nitric oxide (NO);
a diesel oxidation catalyst (DOC) configured to receive the exhaust of the internal combustion engine and, in a first stage, decrease a concentration of the NO2 at a first concentration to a second concentration using an additive and reducing a portion of the NO2 to NO and, in a second stage, increase the concentration of the NO2 from the second concentration to a third concentration by oxidizing a portion of the NO to NO2, wherein the third concentration of the NO2 is less than the first concentration; and
a controller configured to:
receive data from a detector measuring the exhaust gas;
calculate a concentration of NO2 in the exhaust gas;
determine if a ratio of the NO2 to NO is within a range; and
upon determining that the ratio of the NO2 to NO is above the range, increasing an amount of an additive into the DOC, wherein the DOC receives the exhaust gas;
upon determining that the ratio of the NO2 to NO is at or within the range, maintaining the amount of the additive into the DOC; or
upon determining that the ratio of the NO2 to NO is below the range, decreasing the amount of the additive into the DOC.
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