Abstract: A system for a vehicle includes a filtering module and an indicated work module. The filtering module generates engine speeds based on positions of teeth of a toothed wheel that rotates with a crankshaft and based on a crankshaft position signal generated by a crankshaft position sensor. The crankshaft position sensor generates the crankshaft position signal based on rotation of the toothed wheel. The indicated work module generates an indicated work for a combustion cycle of a cylinder of an engine based on squares of first and second ones of the engine speeds and outputs the indicated work.

Abstract: System fault codes, component fault codes, and failure modes may be received at a system. A first level model comprising first level causal relationships and first level causal weights between the system fault codes and the component fault codes may be generated. A second level model comprising second level causal relationships and second level causal weights between the component fault codes and the failure modes may be generated. The first level model and the second level model may be combined to generate a model such as graphical model. One or more causal probabilities may be determined using the graphical model.

Abstract: A system according to the principles of the present disclosure includes a threshold determination module and a misfire detection module. The threshold determination module determines at least one of an acceleration threshold and a jerk threshold based on a misfire type. The misfire detection module detects a misfire in a cylinder of an engine when: (i) crankshaft acceleration is less than the acceleration threshold; and/or (ii) crankshaft jerk is less than the jerk threshold. Crankshaft jerk is a derivative of crankshaft acceleration with respect to time.

Abstract: A system according to the principles of the present disclosure includes a threshold determination module and a misfire detection module. The threshold determination module determines at least one of an acceleration threshold and a jerk threshold based on a misfire type. The misfire detection module detects a misfire in a cylinder of an engine when: (i) crankshaft acceleration is less than the acceleration threshold; and/or (ii) crankshaft jerk is less than the jerk threshold. Crankshaft jerk is a derivative of crankshaft acceleration with respect to time.

Abstract: A system for an engine includes first, second, third, and fourth modules. The first module determines an expected response of crankshaft speed due to combustion within a cylinder of the engine. The second module determines a value based on the expected response and a measured response of crankshaft speed due to combustion within the cylinder of the engine. The third module estimates an indicated mean effective pressure (IMEP) for the cylinder of the engine based on the value. The fourth module selectively adjusts an operating parameter of the engine based in the estimated IMEP.

Abstract: System fault codes, component fault codes, and failure modes may be received at a system. A first level model comprising first level causal relationships and first level causal weights between the system fault codes and the component fault codes may be generated. A second level model comprising second level causal relationships and second level causal weights between the component fault codes and the failure modes may be generated. The first level model and the second level model may be combined to generate a model such as graphical model. One or more causal probabilities may be determined using the graphical model.

Abstract: An engine control system includes a disturbance module, a misfire threshold determination module, a disturbance ratio module, and a spark control module. The disturbance module determines a disturbance value for a past combustion stroke of a cylinder based on rotation of a crankshaft. The misfire threshold determination module determines a jerk value indicative of a misfire within the cylinder. The disturbance ratio module determines a disturbance ratio for the past combustion stroke based on the disturbance value and the jerk value. The spark control module determines a spark timing for a future combustion stroke of the cylinder, determines a spark timing correction for the future combustion stroke based on the disturbance ratio, determines a corrected spark timing based on the spark timing and the spark timing correction, and generates spark during the future combustion stroke based on the corrected spark timing.

Abstract: A system for an engine includes first, second, third, and fourth modules. The first module determines an expected response of crankshaft speed due to combustion within a cylinder of the engine. The second module determines a value based on the expected response and a measured response of crankshaft speed due to combustion within the cylinder of the engine. The third module estimates an indicated mean effective pressure (IMEP) for the cylinder of the engine based on the value. The fourth module selectively adjusts an operating parameter of the engine based in the estimated IMEP.

Abstract: A system for a vehicle includes a filtering module and an indicated work module. The filtering module generates engine speeds based on positions of teeth of a toothed wheel that rotates with a crankshaft and based on a crankshaft position signal generated by a crankshaft position sensor. The crankshaft position sensor generates the crankshaft position signal based on rotation of the toothed wheel. The indicated work module generates an indicated work for a combustion cycle of a cylinder of an engine based on squares of first and second ones of the engine speeds and outputs the indicated work.

Abstract: An engine control system includes a disturbance module, a misfire threshold determination module, a disturbance ratio module, and a spark control module. The disturbance module determines a disturbance value for a past combustion stroke of a cylinder based on rotation of a crankshaft. The misfire threshold determination module determines a jerk value indicative of a misfire within the cylinder. The disturbance ratio module determines a disturbance ratio for the past combustion stroke based on the disturbance value and the jerk value. The spark control module determines a spark timing for a future combustion stroke of the cylinder, determines a spark timing correction for the future combustion stroke based on the disturbance ratio, determines a corrected spark timing based on the spark timing and the spark timing correction, and generates spark during the future combustion stroke based on the corrected spark timing.

Abstract: A control system includes a jerk determination module and a misfire confirmation module. The jerk determination module determines a jerk of a crankshaft associated with a firing event in an engine. The misfire confirmation module selectively confirms that a misfire detected in the engine is valid based on the jerk.

Abstract: A control system includes a jerk determination module and a misfire confirmation module. The jerk determination module determines a jerk of a crankshaft associated with a firing event in an engine. The misfire confirmation module selectively confirms that a misfire detected in the engine is valid based on the jerk.