Aftertreatment for alcohol fuel substituted diesel engines

A controller for controlling emissions of an internal combustion engine system, the controller comprising:

• a memory storing computer-executable instructions;
• and
• a processor in communication with the memory, the computer-executable instructions causing the processor to perform acts comprising:
• receiving data from a detector measuring an exhaust gas created by a combustion of a first fuel and a second fuel;
• calculating a concentration of NO2 in the exhaust gas;
• determining 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 a diesel oxidation catalyst (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.

A method of controlling emissions of an internal combustion engine, comprising:

• receiving detector data of an exhaust of the internal combustion engine created by a combustion of a first fuel and a second fuel in the internal combustion engine, wherein a portion of the exhaust comprises nitrogen dioxide (NO2) and nitric oxide (NO);
• using the detector data, calculating NO2 concentration in the exhaust;
• determining that the NO2 concentration is above a range;
• and
• increasing an amount of an additive entering a diesel oxidation catalyst (DOC) receiving the exhaust, wherein the DOC is configured to:
• in a first stage, decrease the concentration of the NO2 at a first concentration to a second concentration using the 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.