Apparatus, method, and system for diagnosing reductant delivery performance

A system, comprising:

• a reductant delivery system comprising a reductant pump;
• and
• a controller configured to:
• determine a flow rate offset value for the reductant delivery system, the flow rate offset value based on a first pump command value for the reductant pump when an output pressure value is stabilized and a first reductant dosing command value is zero,
• determine a first reduced reductant flow rate for a second reductant dosing command value based, at least in part, on the determined flow rate offset value, the second reductant dosing command being non-zero,
• determine a first reductant flow rate error based, at least in part, on a difference between a reductant flow rate value corresponding to the second reductant dosing command value and the first determined reduced reductant flow rate,
• determine a second reduced reductant flow rate for the second reductant dosing command value based, at least in part, on the determined flow rate offset value,
• determine a second reductant flow rate error based, at least in part, on a difference between the reductant flow rate value corresponding to the second reductant dosing command value and the second determined reduced reductant flow rate,
• determine an accumulated error value based, at least in part, on the first reductant flow rate error and the second reductant flow rate error, and
• output a performance status value indicative of a performance status of the reductant delivery system based on the determined accumulated error value and the predetermined threshold.

A non-transitory computer-readable medium storing one or more instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

• determining a reductant flow rate offset value for a reductant delivery system, the reductant flow rate offset value based on a first pump command value for a reductant pump when an output pressure value from a pressure sensor is stabilized and a first reductant dosing command value controlling an amount of reductant to a delivery mechanism of the reductant delivery system is zero;
• determining a second pump command value for the reductant pump when the output pressure value from the pressure sensor is stabilized for a second reductant dosing command value, the second reductant dosing command value being non-zero;
• determining a first reduced reductant flow rate for the second reductant dosing command value based on the determined reductant flow rate offset value and the second pump command value;
• determining a first reductant flow rate error based, at least in part, on a difference between a reductant flow rate value corresponding to the second reductant dosing command value and the first determined reduced reductant flow rate;
• and
• outputting a performance status value indicative of a performance status of the reductant delivery system based, at least in part, on the determined first reductant flow rate error and a predetermined threshold.

A non-transitory computer-readable medium storing one or more instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

• determining a flow rate offset value for a reductant delivery system, the flow rate offset value based on a first pump command value for a reductant um when an output pressure value is stabilized and a first reductant dosing command value is zero;
• determining a second pump command value for the reductant pump when the output pressure value is stabilized for a second reductant dosing command value, the second reductant dosing command value being non-zero;
• determining a first reduced reductant flow rate for the second reductant dosing command value based on the determined flow rate offset value and the second pump command value;
• determining a first reductant flow rate error based, at least in part, on a difference between a reductant flow rate value corresponding to the second reductant dosing command value and the first determined reduced reductant flow rate;
• determining a second reduced reductant flow rate for the second reductant dosing command value based, at least in part, on the determined flow rate offset value;
• determining a second reductant flow rate error based, at least in part, on a difference between the reductant flow rate value corresponding to the second reductant dosing command value and the second determined reduced reductant flow rate;
• determining an accumulated error value based, at least in part, on the first reductant flow rate error and the second reductant flow rate error;
• and
• outputting a performance status value indicative of a performance status of the reductant delivery system based on the determined accumulated error value and the predetermined threshold.

A method for determining a performance status of a reductant delivery system comprising a reductant pump, a control valve, and a delivery mechanism, the method comprising:

• determining, using one or more data processors, an internal flow rate offset value of the reductant delivery system;
• determining, using one or more data processors, a reductant flow rate model based on the determined internal flow rate offset value and a slope value, the reductant flow rate model generating an expected reductant flow rate for a normal-operating reductant delivery system responsive to an inputted pump command value;
• outputting, using one or more data processors, a reductant dosing command value based on a desired reductant dosing flow rate to the control valve;
• determining, using one or more processors, a pump command value based on the reductant dosing command value;
• determining, using one or more data processors, a reduced reductant flow rate based on the determined reductant flow rate model and the determined pump command value;
• determining, using one or more data processors, a reductant flow rate error value based, at least in part, on a difference between the desired reductant dosing rate and the determined reduced reductant flow rate;
• and
• outputting a performance status value indicative of a performance of the reductant delivery system based on the reductant flow rate error value and a predetermined threshold value.