Abstract: A system for diagnosing a switchable roller finger follower (SRFF) and an oil control valve (OCV) includes a signal monitoring module and a fault detection module. The signal monitoring module receives at least one of an individual cylinder fuel correction (ICFC) signal and an air/fuel ratio imbalance (AFIM) signal when: an engine speed signal is within a predetermined range of speed; an engine load signal is within a predetermined range of load; and a charcoal canister vapor signal is within a predetermined range of flow rate. The fault detection module detects a fault of at least one of a SRFF and an OCV based on an exhaust gas recirculation value and at least one of the ICFC and AFIM signals. The ICFC and AFIM signals are generated based on: an engine position signal; and at least one of an oxygen signal and a wide range air fuel signal.

Abstract: An air/fuel imbalance (AFIM) diagnostic system comprises a first module, an imbalance determination module, and an imbalance diagnostic module. The first module outputs imbalance data samples based on an oxygen signal provided by an oxygen sensor measuring oxygen in exhaust expelled from cylinders of a cylinder bank. The imbalance determination module determines an AFIM value based on the imbalance data samples. The imbalance diagnostic module selectively diagnoses an AFIM in the cylinder bank based on the AFIM value.

Abstract: A method and system for controlling an engine includes a normal individual cylinder fuel correction determination module determining normal pulse mode individual cylinder fuel corrections in a normal pulse mode. The system also includes a split pulse enable module operating the fuel injectors in split pulse mode having a linear pulse and a ballistic pulse smaller than the linear pulse. The system also includes a split pulse individual cylinder fuel correction determination module determining split pulse mode individual cylinder fuel corrections in the split pulse mode. The system also includes a ballistic pulse adaptation module adjusting ballistic pulse calibration values in response to the normal pulse mode individual cylinder fuel corrections and the split pulse mode individual cylinder fuel corrections to form adjusted ballistic pulse calibration values.

Abstract: A system for diagnosing a switchable roller finger follower (SRFF) and an oil control valve (OCV) includes a signal monitoring module and a fault detection module. The signal monitoring module receives at least one of an individual cylinder fuel correction (ICFC) signal and an air/fuel ratio imbalance (AFIM) signal when: an engine speed signal is within a predetermined range of speed; an engine load signal is within a predetermined range of load; and a charcoal canister vapor signal is within a predetermined range of flow rate. The fault detection module detects a fault of at least one of a SRFF and an OCV based on an exhaust gas recirculation value and at least one of the ICFC and AFIM signals. The ICFC and AFIM signals are generated based on: an engine position signal; and at least one of an oxygen signal and a wide range air fuel signal.

Abstract: A method and system for controlling an engine includes a normal individual cylinder fuel correction determination module determining normal pulse mode individual cylinder fuel corrections in a normal pulse mode. The system also includes a split pulse enable module operating the fuel injectors in split pulse mode having a linear pulse and a ballistic pulse smaller than the linear pulse. The system also includes a split pulse individual cylinder fuel correction determination module determining split pulse mode individual cylinder fuel corrections in the split pulse mode. The system also includes a ballistic pulse adaptation module adjusting ballistic pulse calibration values in response to the normal pulse mode individual cylinder fuel corrections and the split pulse mode individual cylinder fuel corrections to form adjusted ballistic pulse calibration values.

Abstract: An air/fuel imbalance (AFIM) diagnostic system comprises a first module, an imbalance determination module, and an imbalance diagnostic module. The first module outputs imbalance data samples based on an oxygen signal provided by an oxygen sensor measuring oxygen in exhaust expelled from cylinders of a cylinder bank. The imbalance determination module determines an AFIM value based on the imbalance data samples. The imbalance diagnostic module selectively diagnoses an AFIM in the cylinder bank based on the AFIM value.

Abstract: A method of estimating an air charge in at least one combustion cylinder of an internal combustion engine includes calculating cylinder mass air flow based upon a modified volumetric efficiency parameter; and calculating the intake throttle mass air flow based upon a throttle air flow discharge parameter and a fuel enrichment factor. Three models including a mean-value cylinder flow model, a manifold dynamics model, and a throttle flow model are provided to estimate the air charge in the at least one combustion cylinder and to control delivery of fuel to the fuel delivery system.

Abstract: A method of estimating an air charge in at least one combustion cylinder of an internal combustion engine includes calculating cylinder mass air flow based upon a modified volumetric efficiency parameter; and calculating the intake throttle mass air flow based upon a throttle air flow discharge parameter and a fuel enrichment factor. Three models including a mean-value cylinder flow model, a manifold dynamics model, and a throttle flow model are provided to estimate the air charge in the at least one combustion cylinder and to control delivery of fuel to the fuel delivery system.

Abstract: An improved individual cylinder fuel control method based on sampled readings of a single oxygen sensor responsive to the combined exhaust gas flow of several engine cylinders. A model-based observer is used to reproduce the imbalances of the different cylinders and a proportional-plus-integral controller is used for their elimination. Both the observer and the controller are formulated in terms of a periodic system. The observer input signal is preprocessed such that it reflects at each point of time the deviation from the current A/F-ratio mean value calculated over two engine cycles. Therefore, transient engine operating conditions do not harm the reconstruction of the cylinder imbalances dramatically. The control algorithm features process/controller synchronization based on table lookup and a mechanism to automatically adjust the mapping between the observer estimates and the corresponding cylinders if unstable control operation is detected.