Abstract: A variable displacement internal combustion engine control system includes an engine having cylinders, each having an intake valve and an exhaust valve. An engine control module determines when to activate and deactivate the cylinders, and when to purge gas entrained in an oil system. A solenoid-actuated hydraulic control valve communicates with the engine control module to deactivate and activate individual cylinders. An air accumulation estimation program running multiple times per second for each of the cylinders identifies an approximate gas volume accumulating in a control port of the solenoid-actuated hydraulic control valve and if the gas volume has reached a predetermined threshold allows a purge pulse to be issued. The purge pulse initiates at a purge pulse initiation point during one of intake valve lift, exhaust valve lift, and when valve lifters of both the intake and the exhaust valve are on a base circle providing zero lift.

Abstract: An engine control system includes a cylinder control module that deactivates and reactivates a cylinder of an engine based on a driver torque request while an ignition system associated with the engine is in an on position. A firing order module selectively adjusts a firing order of the engine based on a time when the cylinder is reactivated.

Abstract: A cylinder control module: selects one of N predetermined cylinder activation/deactivation patterns as a desired cylinder activation/deactivation pattern for cylinders of an engine, wherein N is an integer greater than two; and activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation pattern, respectively. A fuel control module provides fuel to the first ones of the cylinders and disables fueling to the second ones of the cylinders. The cylinder control module further: determines M possible ones of the N cylinder activation/deactivation patterns, wherein M is an integer greater than or equal to one; selectively compares the M possible cylinder activation/deactivation patterns with the desired cylinder activation/deactivation pattern; and selectively updates the desired cylinder activation/deactivation pattern to one of the M possible cylinder activation/deactivation patterns.

Abstract: A method to adjust an oil control valve actuation response time using cylinder valve diagnostic results includes commanding an engine cylinder to deactivate/reactive when conditions are met and then detecting if a deactivation/reactivation response time failure has occurred by analyzing the cylinder diagnostics results. If a predetermined number of failures are detected at the cylinder within a predetermined number of engine cycles then the engine controller operates to adjust the oil control valve response time to improve the response time accuracy.

Abstract: A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire or other dynamic firing level modulation operation of an engine. In general, actuator first transition strategies are described in which an actuator position (e.g., cam phase, TCC slip, etc.) is changed to, or close to a target position before a corresponding firing fraction change is implemented. When the actuator change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps. A number of intermediate target selection schemes are described as well.

Abstract: A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire or other dynamic firing level modulation operation of an engine. In general, actuator first transition strategies are described in which an actuator position (e.g., cam phase, TCC slip, etc.) is changed to, or close to a target position before a corresponding firing fraction change is implemented. When the actuator change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps. A number of intermediate target selection schemes are described as well.

Abstract: A method to adjust an oil control valve actuation response time using cylinder valve diagnostic results includes commanding an engine cylinder to deactivate/reactive when conditions are met and then detecting if a deactivation/reactivation response time failure has occurred by analyzing the cylinder diagnostics results. If a predetermined number of failures are detected at the cylinder within a predetermined number of engine cycles then the engine controller operates to adjust the oil control valve response time to improve the response time accuracy.

Abstract: A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire and potentially variable displacement operation of an engine. In general, cam first transition strategies are described in which the cam phase is changed to, or close to a target cam phase before a corresponding firing fraction change is implemented. When the cam phase change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps—with each step using a cam first transition approach. A number of intermediate target selection schemes are described as well.

Abstract: A method for operating an internal combustion engine includes providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions, providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions, determining a torque capacity of each of the plurality firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq), determining a plurality of viable firing fractions of the plurality of available firing fractions, and determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction.

Abstract: A method for operating an internal combustion engine includes providing a vehicle having an internal combustion gasoline engine including multiple cylinders and wherein the engine is capable of running on at least one of a plurality firing fractions, providing a vacuum offset (Offsetvac) to adjust airflow capacity for each of the plurality of firing fractions, determining a torque capacity of each of the plurality firing fractions and a plurality of available firing fractions that provides at least enough torque capacity to accommodate a current torque requested (Treq), determining a plurality of viable firing fractions of the plurality of available firing fractions, and determining and implementing an optimal firing fraction of the viable firing fractions if the optimal firing fraction provides enough fuel economy benefit over a current firing fraction.

Abstract: A variety of methods and arrangements are described for controlling transitions between firing fractions during skip fire and potentially variable displacement operation of an engine. In general, cam first transition strategies are described in which the cam phase is changed to, or close to a target cam phase before a corresponding firing fraction change is implemented. When the cam phase change associated with a desired firing fraction change is relatively large, the firing fraction change is divided into a series of two or more firing fraction change steps—with each step using a cam first transition approach. A number of intermediate target selection schemes are described as well.

Abstract: A system according to the principles of the present disclosure includes a cylinder activation module and a spark control module. The cylinder activation module selectively deactivates and reactivates a cylinder of an engine. The cylinder activation module deactivates the cylinder after intake air is drawn into the cylinder and before fuel is injected into the cylinder or spark is generated in the cylinder. When the cylinder is reactivated, the spark control module selectively controls a spark plug to generate spark in the cylinder before an intake valve or an exhaust valve of the cylinder is opened.

Abstract: An engine control system includes a cylinder control module that deactivates and reactivates a cylinder of an engine based on a driver torque request while an ignition system associated with the engine is in an on position. A firing order module selectively adjusts a firing order of the engine based on a time when the cylinder is reactivated.

Abstract: A system according to the principles of the present disclosure includes a cylinder control module and a valve control module. The cylinder control module deactivates and reactivates a cylinder of an engine based on a driver torque request while an ignition system associated with the engine is in an on position. The valve control module selectively adjusts a period for which at least one of an intake valve and an exhaust valve of the cylinder are opened based on a first time when the cylinder is reactivated.

Abstract: A ranking module determines N ranking values for N predetermined cylinder activation/deactivation sequences of an engine, respectively. N is an integer greater than or equal to two. A cylinder control module, based on the N ranking values, selects one of the N predetermined cylinder activation/deactivation sequences as a desired cylinder activation/deactivation sequence for cylinders of the engine. The cylinder control module also: activates opening of intake and exhaust valves of first ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation sequence; and deactivates opening of intake and exhaust valves of second ones of the cylinders that are to be deactivated based on the desired cylinder activation/deactivation sequence. A fuel control module provides fuel to the first ones of the cylinders and disables fueling to the second ones of the cylinders.

Abstract: A system includes a net mean effective pressure (NMEP) error module, a correction determination module, a mean effective pressure (MEP) correction module, and an actuator control module. The NMEP error module determines an NMEP error for a combustion cycle of a cylinder based on an expected NMEP for the combustion cycle, a measured NMEP for the combustion cycle, and a difference between an expected change in an engine speed for the combustion cycle and a measured change in the engine speed for the combustion cycle. The correction determination module determines an offset correction and a slope correction based on the NMEP error. The MEP correction module that generates a corrected NMEP for the combustion cycle based on the measured NMEP, the offset correction, and the slope correction. The actuator control module controls an engine operating parameter based on the corrected NMEP.

Abstract: A system for a vehicle, includes first, second, and third setpoint generation modules, a scaling module, and an actuator control module. The first setpoint generation module generates a first target value for an combustion parameter of an engine based on a predetermined value of a combustion stability of the engine. The second setpoint generation module generates a second target value for the combustion parameter based on a predetermined fuel efficiency. The scaling module generates a scaled value for the combustion parameter based on the first and second target values and a scalar value. The third setpoint generation module generates a third target value for the combustion parameter based on the first target value and the scaled value. The actuator control module controls at least one engine actuator associated with the combustion parameter based on the third target value.

Abstract: A control system and method for operating an engine includes a threshold determination module that determines a plurality of combustion mode thresholds based on the engine speed and engine temperature. The control module also includes a transition module that compares the engine load and the plurality of combustion mode thresholds and changes a combustion mode of the engine in response to comparing the engine load and the plurality of combustion mode thresholds.

Abstract: A cylinder control module: selects one of N predetermined cylinder activation/deactivation patterns as a desired cylinder activation/deactivation pattern for cylinders of an engine, wherein N is an integer greater than two; and activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated based on the desired cylinder activation/deactivation pattern, respectively. A fuel control module provides fuel to the first ones of the cylinders and disables fueling to the second ones of the cylinders. The cylinder control module further: determines M possible ones of the N cylinder activation/deactivation patterns, wherein M is an integer greater than or equal to one; selectively compares the M possible cylinder activation/deactivation patterns with the desired cylinder activation/deactivation pattern; and selectively updates the desired cylinder activation/deactivation pattern to one of the M possible cylinder activation/deactivation patterns.

Abstract: A system according to the principles of the present disclosure includes a cylinder activation module and a spark control module. The cylinder activation module selectively deactivates and reactivates a cylinder of an engine. The cylinder activation module deactivates the cylinder after intake air is drawn into the cylinder and before fuel is injected into the cylinder or spark is generated in the cylinder. When the cylinder is reactivated, the spark control module selectively controls a spark plug to generate spark in the cylinder before an intake valve or an exhaust valve of the cylinder is opened.