Abstract: An internal combustion engine includes an electronic controller programmed to determine, for at least one combustion event in a combustion chamber, a theoretical polytropic constant, a measured polytropic constant, and a difference between the theoretical polytropic constant and the measured polytropic constant. The electronic controller is further programmed to calculate an adjusted pressure signal based on the pressure signal and the difference such that the adjusted pressure signal compensates for changes to an accuracy of the pressure sensor over time.

Abstract: An internal combustion engine includes an electronic controller programmed to determine, for at least one combustion event in a combustion chamber, a theoretical polytropic constant, a measured polytropic constant, and a difference between the theoretical polytropic constant and the measured polytropic constant. The electronic controller is further programmed to calculate an adjusted pressure signal based on the pressure signal and the difference such that the adjusted pressure signal compensates for changes to an accuracy of the pressure sensor over time.

Abstract: A pressure sensor disposed to sense an engine cylinder pressure provides a pressure signal, and an engine timing sensor provides an engine timing signal to an electronic controller, which is programmed to receive and analyze the pressure and engine timing signals to determine a misfire signal, a peak pressure signal, a pressure rise rate, an actual ignition signal, and a center of combustion signal. The electronic controller is further programmed to activate a fault flag when at least one of the misfire signal, the peak pressure signal, the pressure rise rate, the actual ignition signal, and the center of combustion signal, indicates that an abnormal combustion is present in the cylinder.

Abstract: An electronic controller for an engine is programmed to operate in a prognostic mode, in which a baseline record of combustion parameters is created and stored in non-volatile memory, and in a diagnostic mode, in which an operating set of combustion parameters is compiled. During operation, the electronic controller retrieves the baseline record and compares it with the operating set to determine, in real time during engine operation, whether an abnormal combustion is present in the cylinder. The electronic controller activates at least one failure flag when the abnormal combustion is determined to be present.

Abstract: An exhaust system for use with a combustion engine is disclosed. The exhaust system may have an exhaust passage, a reduction catalyst disposed within the exhaust passage, and an injection device configured to inject reductant into the exhaust passage. The exhaust system may also have a sensor configured to generate a signal indicative of a concentration of an exhaust constituent and the reductant, and a controller in communication with the sensor and the injection device. The controller may be configured to make a comparison of a value indicative of a rate of change of the signal for a period of time with a threshold amount, and make a determination of whether the sensor is sensing a concentration of the exhaust constituent or the reductant based on the comparison. The controller may also be configured to adjust operation of the injection device based on the determination.

Abstract: An exhaust system for use with a combustion engine is disclosed. The exhaust system may have an exhaust passage, a reduction catalyst disposed within the exhaust passage, and an injection device configured to inject reductant into the exhaust passage. The exhaust system may also have a sensor configured to generate a signal indicative of a concentration of an exhaust constituent and the reductant, and a controller in communication with the sensor and the injection device. The controller may be configured to make a comparison of a value indicative of a rate of change of the signal for a period of time with a threshold amount, and make a determination of whether the sensor is sensing a concentration of the exhaust constituent or the reductant based on the comparison. The controller may also be configured to adjust operation of the injection device based on the determination.