Integrative reductant system and method using constant volume injection

An aftertreatment system for treating exhaust gas in an inlet exhaust pipe of an internal combustion engine using a reductant, the aftertreatment system comprising:

• a pump configured to receive the reductant;
• an injector configured to inject the reductant in a plurality of constant volume pulses into the exhaust pipe, each of the plurality of constant volume pulses having a volume;
• a sensor configured to determine a characteristic of the exhaust gas;
• and
• a controller configured to:
• receive the characteristic from the sensor;
• determine a dosage rate of the reductant based on the characteristic;
• determine a dosage amount of the reductant by integrating the dosage rate over a target interval;
• compare the dosage amount to the volume;
• initiate a timer indicating a time, in response to determining that the dosage amount is greater than the volume;
• compare the time indicated by the timer to a timer threshold;
• cause the injector to inject the reductant in one of the plurality of constant volume pulse in response to determining that the dosage amount is greater than the volume;
• after causing the injector to inject the reductant in the one of the plurality of constant volume pulses, cause the injector to inject the reductant in another of the plurality of constant volume pulses in response to determining that the time indicated by the timer is greater than the timer threshold;
• and
• reset the time indicated by the timer in response to determining that the dosage amount is not greater than the volume.