Abstract: A reductant delivery system for an internal combustion engine is arranged to inject a reductant into the exhaust aftertreatment system upstream of a catalytic device. A method for controlling the reductant delivery system includes operating the fluidic pump at a preset state, operating the injector at a zero-flow state, and monitoring, via a pressure sensor, a pressure in the reductant delivery system upstream of the injector to determine a zero-flow pressure. The injector is activated under a preset condition and an actual pressure drop upstream of the injector is monitored. A pressure drop deviation is determined based upon the actual pressure drop upstream of the injector and an expected pressure drop upstream of the injector. An adjustment to the activation of the injector is determined based upon the pressure drop deviation, and the injector is controlled based upon the adjustment.

Abstract: A reductant delivery system for an internal combustion engine is arranged to inject a reductant into the exhaust aftertreatment system upstream of a catalytic device. A method for controlling the reductant delivery system includes operating the fluidic pump at a preset state, operating the injector at a zero-flow state, and monitoring, via a pressure sensor, a pressure in the reductant delivery system upstream of the injector to determine a zero-flow pressure. The injector is activated under a preset condition and an actual pressure drop upstream of the injector is monitored. A pressure drop deviation is determined based upon the actual pressure drop upstream of the injector and an expected pressure drop upstream of the injector. An adjustment to the activation of the injector is determined based upon the pressure drop deviation, and the injector is controlled based upon the adjustment.

Abstract: A method for analyzing a fuel injection system includes generating injection commands, including attenuating a predetermined fuel request schedule for a different one of the plurality of injectors in a plurality of test cycles. Fuel is injected according to the injection commands to complete the plurality of test cycles. The processor generates pump commands for the pump to maintain a substantially constant pressure of the common rail during the test cycles. First command data are stored for the plurality of test cycles corresponding to the injection commands sent during the test cycles. Second command data are stored for the test cycles corresponding to the pump commands sent during the test cycles. The processor processes the first command data and the second command data to determine flow characteristics of the plurality of fuel injectors.

Abstract: A method for analyzing a fuel injection system includes generating injection commands, including attenuating a predetermined fuel request schedule for a different one of the plurality of injectors in a plurality of test cycles. Fuel is injected according to the injection commands to complete the plurality of test cycles. The processor generates pump commands for the pump to maintain a substantially constant pressure of the common rail during the test cycles. First command data are stored for the plurality of test cycles corresponding to the injection commands sent during the test cycles. Second command data are stored for the test cycles corresponding to the pump commands sent during the test cycles. The processor processes the first command data and the second command data to determine flow characteristics of the plurality of fuel injectors.

Abstract: A method is disclosed for diagnosing the reliability of a pressure sensor disposed in a fuel rail of an internal combustion engine. A control cycle is executed to measure a value of a fuel rail pressure with the pressure sensor, determine a first and a second threshold value of the fuel rail pressure, identify the measured value of the fuel rail pressure as reliable when the measured value is inside an interval of values ranging from the first threshold value to the second threshold value, and identify the measured value of the fuel rail pressure as unreliable when the measured value is outside that interval. The first and the second threshold values may be determined on the basis of a last reliable value of the fuel rail pressure.

Abstract: A method is disclosed for diagnosing the reliability of a pressure sensor disposed in a fuel rail of an internal combustion engine. A control cycle is executed to measure a value of a fuel rail pressure with the pressure sensor, determine a first and a second threshold value of the fuel rail pressure, identify the measured value of the fuel rail pressure as reliable when the measured value is inside an interval of values ranging from the first threshold value to the second threshold value, and identify the measured value of the fuel rail pressure as unreliable when the measured value is outside that interval. The first and the second threshold values may be determined on the basis of a last reliable value of the fuel rail pressure.