Abstract: A control system is provided to a reductant dosing system for actively maintaining the reductant dosing system ready for use by flushing unused reductant that has crystallized at a return valve of the reductant dosing system. The control system includes a controller that can control a manner of operation of specific system hardware that is present in the reductant dosing system to flush the unused reductant from the return valve that could otherwise cause the return valve to remain a flow-blocking condition as a result of the crystallized reductant.

Abstract: A reductant dosing system is disclosed as having a pump, and suction, discharge, and return passages. The system may also have a return valve, an air passage, and an air valve. The system may additionally have an air passage pressure sensor, a discharge passage pressure sensor, and a controller. The controller may be configured to calculate a first average pressure inside the discharge passage while the pump is off, the air valve is open, and the return valve is closed; and calculate a second average pressure inside the discharge passage while the pump is off, the air valve is open, and the return valve is open. The controller may also be configured to determine a pressure drop inside the discharge passage based on the first and second average pressures, and to determine that priming is successful based on the pressure drop and pressures of the discharge and air passages.

Abstract: A reductant dosing system is disclosed as having a pump, and suction, discharge, and return passages. The system may also have a return valve, an air passage, and an air valve. The system may additionally have an air passage pressure sensor, a discharge passage pressure sensor, and a controller. The controller may be configured to calculate a first average pressure inside the discharge passage while the pump is off, the air valve is open, and the return valve is closed; and calculate a second average pressure inside the discharge passage while the pump is off, the air valve is open, and the return valve is open. The controller may also be configured to determine a pressure drop inside the discharge passage based on the first and second average pressures, and to determine that priming is successful based on the pressure drop and pressures of the discharge and air passages.

Abstract: A method of introducing reductant to an exhaust stream is disclosed. The method may include ordering a first dosing event, supplying a reductant to a dispensing device in response to ordering the first dosing event, dispensing reductant from the dispensing device into the exhaust stream, and forcing reductant from the dispensing device toward a reductant source, wherein sufficient reductant remains in a pumping device and a fluid passage to keep the pumping device primed.

Abstract: Methods of monitoring replacement of a diesel particulate filter (DPF) by a non-particulate matter filter. The disclosed methods takes into account a change in delta pressure based soot load estimates (DPSLE) over time to detect whether the DPF has been replaced. The estimate, which is measured by the delta pressure drop across the filter, can be used to determine whether a device that does not have the capability of trapping soot, such as a muffler, has been inserted.

Abstract: A method of introducing reductant to an exhaust stream is disclosed. The method may include ordering a first dosing event, supplying a reductant to a dispensing device in response to ordering the first dosing event, dispensing reductant from the dispensing device into the exhaust stream, and forcing reductant from the dispensing device toward a reductant source, wherein sufficient reductant remains in a pumping device and a fluid passage to keep the pumping device primed.

Abstract: Methods of monitoring replacement of a diesel particulate filter (DPF) by a non-particulate matter filter. The disclosed methods takes into account a change in delta pressure based soot load estimates (DPSLE) over time to detect whether the DPF has been replaced. The estimate, which is measured by the delta pressure drop across the filter, can be used to determine whether a device that does not have the capability of trapping soot, such as a muffler, has been inserted.