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 diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes determining, by an electronic processor, an operating pressure, and receiving, from a pressure sensor of the DEF delivery system, a system pressure. The method further includes determining, by the processor, a dosing request and a pressure disturbance based on the dosing request. The method further includes determining, by the processor, a control request based on the system pressure and the operating pressure, and a feed forward control value based on the pressure disturbance. The method further includes generating, by the processor, an adjusted control request based on the control request based and the feed forward control value. The method further includes controlling, by the processor, a dosing valve of the DEF delivery system based on the dosing request, and a pressure adjustment component of the DEF delivery system based on the adjusted control request.

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 diesel exhaust fluid (DEF) delivery system and method for operating same. The method includes determining, by an electronic processor, an operating pressure, and receiving, from a pressure sensor of the DEF delivery system, a system pressure. The method further includes determining, by the processor, a dosing request and a pressure disturbance based on the dosing request. The method further includes determining, by the processor, a control request based on the system pressure and the operating pressure, and a feed forward control value based on the pressure disturbance. The method further includes generating, by the processor, an adjusted control request based on the control request based and the feed forward control value. The method further includes controlling, by the processor, a dosing valve of the DEF delivery system based on the dosing request, and a pressure adjustment component of the DEF delivery system based on the adjusted control request.

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 method for assessing a ripple of a signal, includes: a) determining a first signal value at a determination point in time, b) determining a signal value difference between the first signal value and a signal value determined at a previous determination point in time, c) incrementing an undershoot counter if the signal value difference falls below a first difference threshold value, and incrementing an overshoot counter and resetting the undershoot counter if the signal value difference exceeds a second difference threshold value, and d) determining that no ripple overshoot is present and resetting the overshoot counter if the undershoot counter overshoots an undershoot threshold value, and determining that a ripple overshoot is present if the overshoot counter exceeds an overshoot threshold value and the undershoot counter does not exceed an undershoot threshold value.

Abstract: A method for assessing a ripple of a signal, includes: a) determining a first signal value at a determination point in time, b) determining a signal value difference between the first signal value and a signal value determined at a previous determination point in time, c) incrementing an undershoot counter if the signal value difference falls below a first difference threshold value, and incrementing an overshoot counter and resetting the undershoot counter if the signal value difference exceeds a second difference threshold value, and d) determining that no ripple overshoot is present and resetting the overshoot counter if the undershoot counter overshoots an undershoot threshold value, and determining that a ripple overshoot is present if the overshoot counter exceeds an overshoot threshold value and the undershoot counter does not exceed an undershoot threshold value.