Control system for a reductant dosing system

A reductant dosing system comprising:

• a first reservoir configured to store reductant therein;
• a pump fluidly coupled to the reservoir via a first reductant supply line;
• a reductant dosing injector disposed in fluid communication with the pump;
• a first pressure sensor configured to output a value indicative of pressure in the first reductant supply line;
• and
• a return valve disposed in a return line and positioned between the pump and the reductant dosing injector and fluidly coupled to the first reservoir downstream of the return valve;
• a supply of pressurized air connected to the reductant dosing injector via an air supply line;
• an air supply valve disposed in the air supply line and configured to selectively allow flow of air from the source to the reductant dosing injector;
• a second pressure sensor located between the air supply valve and the reductant dosing injector, the second pressure sensor configured to output a value indicative of pressure in the air supply line;
• and
• a controller communicably coupled to the pump, the first pressure sensor, the second pressure sensor, the return valve, and the air supply valve, the controller configured to:
• obtain a value of pressure in the air supply line from the second pressure sensor,
• obtain a value of pressure in the reductant supply line from the first pressure sensor,
• compare the pressure in the reductant supply line with the pressure in the air supply line,
• close the air supply valve and open the return valve,
• determine whether the pressure in the reductant supply line is greater than a first pre-defined value,
• operate the pump,
• open the air supply valve upon lapse of a first pre-determined amount of time,
• discontinue operation of the pump upon lapse of a second pre-determined amount of time, and
• cycle the return valve between its open and closed states while continuing to supply compressed air into the reductant supply line via the opened air supply valve until the pressure in the reductant supply line recedes to a value less than a second pre-defined value, the second pre-defined value being less than the first pre-defined value.

A method for flushing a return valve associated with a reductant supply circuit of a reductant dosing system, the method comprising:

• obtaining, using a first pressure sensor, a value of pressure in a reductant supply line of the reductant supply circuit,
• obtaining, using a second pressure sensor, a value of pressure in an air supply line of the air supply circuit,
• determining, using a controller communicably coupled to the first and second pressure sensors, whether the air supply line and the reductant supply line are hermetically sealed based on a comparison of the pressure in the reductant supply line with the pressure in the air supply line,
• confirming, by the controller, that the return valve is blocked by opening the return valve and determining Whether the pressure in the reductant supply line remains greater than a first pre-defined value, and
• operating, by the controller, a pump disposed in the reductant supply line in response to a confirmation by the controller that the return valve is blocked;
• opening the air supply valve, by the controller, upon lapse of a first pre-determined amount of time from commencement of operation of the pump,
• discontinuing operation of the pump, by the controller, upon lapse of a second pre-determined amount of time from commencement of operation of the pump, and
• cyclically moving the return valve between its open and closed states, by the controller, while continuing to supply compressed air into the reductant supply line until the pressure in the reductant supply line recedes to a value less than a second pre-defined value, the second pre-defined value being less than the first pre-defined value.