Abstract: A system for regulating pressure in a diesel exhaust fluid delivery system. The system includes a first dosing valve, a pump, a hydraulic line, and an electronic processor. The electronic processor is configured to determine a dosing demand, determine a time delay between the first dosing valve opening and the pump activating, and determine a first threshold time and a second threshold time based on the time delay. The electronic processor is also configured to activate a timer. When the timer reaches the first threshold time, the electronic processor is configured to freeze the dosing demand and activate the pump based on the dosing demand. When the timer reaches the second threshold time, the electronic processor is configured to open the first dosing valve and release the freeze on the dosing demand.

Abstract: A diesel exhaust fluid delivery system and a dual-variable control strategy for adjusting the delivery pressure and the mass flow rate of the fluid passing through the system. The method for operating the system using two operating modes: low flow rate and high flow rate. While operating in the low flow rate operating mode, the speed of a DEF pump remains constant and DEF delivery to the exhaust system is adjusted by controlling a backflow valve. While operating in the high flow rate operating mode, the backflow valve is closed and the speed of the pump is adjusted to regulate DEF delivery to the exhaust system.

Abstract: A diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes controlling a pump to operate at an idle speed to pressurize a pressure line. The method includes controlling a backflow dosing module (BFDM) valve to open to allow an amount of the DEF to flow into a fluid storage tank through a backflow line. The method includes determining a dosing request, a first dosing actuation request for the first dosing valve and a second dosing actuation request for the second dosing valve based on the dosing request. The method includes, when a sum of the first and second dosing actuation requests is less than 100%, controlling the BFDM valve to close when either of the first and second dosing valves is open; and controlling the BFDM valve to open when the first dosing valve is closed and the second dosing valve is closed.

Abstract: A method and system for detecting whether a pressure line in a diesel exhaust fluid (DEF) delivery system has an obstruction. The system includes an electronic control unit with an electronic processor that is configured to receive an unfiltered pressure signal from a pressure sensor; to electronically filter the unfiltered pressure signal to determine a dosing pressure signal; to determine an integrated value based on the dosing pressure signal; and to determine whether the pressure line is obstructed by comparing the integrated value with a predetermined threshold.

Abstract: A system for regulating pressure in a diesel exhaust fluid delivery system. The system includes a first dosing valve, a pump, a hydraulic line, and an electronic processor. The electronic processor is configured to determine a dosing demand, determine a time delay between the first dosing valve opening and the pump activating, and determine a first threshold time and a second threshold time based on the time delay. The electronic processor is also configured to activate a timer. When the timer reaches the first threshold time, the electronic processor is configured to freeze the dosing demand and activate the pump based on the dosing demand. When the timer reaches the second threshold time, the electronic processor is configured to open the first dosing valve and release the freeze on the dosing demand.

Abstract: A diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes controlling a pump to operate at an idle speed to pressurize a pressure line. The method includes controlling a backflow dosing module (BFDM) valve to open to allow an amount of the DEF to flow into a fluid storage tank through a backflow line. The method includes determining a dosing request, a first dosing actuation request for the first dosing valve and a second dosing actuation request for the second dosing valve based on the dosing request. The method includes, when a sum of the first and second dosing actuation requests is less than 100%, controlling the BFDM valve to close when either of the first and second dosing valves is open; and controlling the BFDM valve to open when the first dosing valve is closed and the second dosing valve is closed.

Abstract: A method and system for detecting whether a pressure line in a diesel exhaust fluid (DEF) delivery system has an obstruction. The system includes an electronic control unit with an electronic processor that is configured to receive an unfiltered pressure signal from a pressure sensor; to electronically filter the unfiltered pressure signal to determine a dosing pressure signal; to determine an integrated value based on the dosing pressure signal; and to determine whether the pressure line is obstructed by comparing the integrated value with a predetermined threshold.

Abstract: A diesel exhaust fluid delivery system and a dual-variable control strategy for adjusting the delivery pressure and the mass flow rate of the fluid passing through the system. The method for operating the system using two operating modes: low flow rate and high flow rate. While operating in the low flow rate operating mode, the speed of a DEF pump remains constant and DEF delivery to the exhaust system is adjusted by controlling a backflow valve. While operating in the high flow rate operating mode, the backflow valve is closed and the speed of the pump is adjusted to regulate DEF delivery to the exhaust system.