AIR-ASSIST DOSING SYSTEM HAVING PRIMING DETECTION

摘要

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.

主权项

1. A reductant dosing system, comprising:
a reductant tank; a pump; a suction passage connecting the pump to the reductant tank; an injector; a discharge passage connecting the pump to the injector; a return passage connecting the discharge passage to the reductant tank; a return valve movable to regulate flow through the return passage; an air supply; an air passage connecting the air supply to the injector; an air valve movable to regulate flow through the air passage; a first pressure sensor associated with the air passage; a second pressure sensor associated with the discharge passage; and a controller in communication with the first pressure sensor, the second pressure sensor, the air valve, and the return valve, the controller being configured to:
calculate a first average pressure inside the discharge passage based on signals from the second pressure sensor while the pump is off, the air valve is open, and the return valve is closed;calculate a second average pressure inside the discharge passage based on signals from the second pressure sensor while the pump is off, the air valve is open, and the return valve is open;determine a pressure drop inside the discharge passage based on the first and second average pressures; anddetermine that priming of the reductant dosing system is successful based on the pressure drop and pressures of the discharge and air passages while the pump is on, the air valve is open, and the return valve is closed.