A variety of methods and arrangements are described for controlling transitions between effective firing fractions during dynamic firing level modulation operation of an engine in order to help reduce undesirable NVH consequences and otherwise smooth the transitions. In general, both feed forward and feedback control are utilized in the determination of the effective firing fractions during transitions such that the resulting changes in the effective firing fraction better track cylinder air charge changing dynamics associated with the transition.

A control system for controlling operation of an internal combustion engine is configured to: receive a first request signal indicative of first torque demand; determine a schedule defining an opening timing of the intake valve and a closing timing of the intake valve of a cylinder of the internal combustion engine in dependence on the first torque demand; and cause the intake valve to open in accordance with the schedule. The control system is also configured to, during a period in which the intake valve is open: receive a second torque request signal indicative of a second torque demand different to the first torque demand; determine an updated schedule defining an updated closing timing of the intake valve in dependence on the second torque demand; and cause the intake valve to close in accordance with the updated schedule.

Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, a position of one or more volumetric efficiency control devices is changed in response to a request to deactivate one or more engine cylinders while at the same time the engine central throttle is adjusted. Spark timing may also be adjusted if engine air flow deviates from a desired engine air flow.

A skip fire engine controller and method of control is described wherein during transitions from a first firing density to a second firing density, a firing density and a pumping density are separately set so as to balance the conflicting demands of (a) torque control, (b) Noise, Vibration and Harshness (NVH), (c) air flow through the engine and (d) air-fuel ratio.

The invention relates to a control device for an internal combustion engine that includes a turbocharger, and an actuator that changes a turbocharging pressure by regulating exhaust energy for use in drive of the turbocharger. When a target torque is increased during execution of a lean burn operation, the control device switches an operation mode of the internal combustion engine from the lean burn operation to a stoichiometric operation. When the operation mode switching is performed in a turbocharging state, the control device determines whether a target torque is within a range of a torque realizable under the lean air-fuel ratio. When the target torque is within the range, the control device operates the actuator so as to keep the turbocharging pressure at a magnitude equal to or larger than a magnitude at a time point at which the operation mode is switched.

A controller for an internal combustion engine includes an electronic control unit. The electronic control unit is configured to increase an air amount that is suctioned into a cylinder while maintaining the lean air-fuel ratio as a first torque increasing operation in a case where target torque is increased during the operation at the lean air-fuel ratio such that torque is increased. The electronic control unit is configured to compute limit torque as an upper limit of the torque that can be realized in a case where the lean air-fuel ratio is kept for a certain time from a current time point. The electronic control unit is configured to switch to the operation at the theoretical air-fuel ratio and increase the torque as a second torque increasing operation in a case where the target torque becomes higher than the limit torque during execution of the first torque increasing operation.

Various methods and arrangements for improving fuel economy and noise, vibration, and harshness (NVH) in a skip fire controlled engine are described. An engine controller dynamically selects a gas spring type for a skipped firing opportunity. Determination of the skip/fire pattern and gas spring type may be made on a firing opportunity by firing opportunity basis.

A powertrain system is described, and includes an internal combustion engine and an electric machine configured to generate propulsion torque responsive to a driver torque request. A method for operating the powertrain system includes determining, in response to a request to execute an engine autostart operation, whether a driveline torque sag may occur. The method further includes forgoing executing the engine autostart operation when it is determined that a driveline torque sag will occur during the execution of the engine autostart operation.

A method and apparatus for continually and rapidly adjusting the output torque of an engine according to a torque demand uses an active tappet to vary the instant air charge in a combustion chamber, so as to modulate engine torque during an automatic change of speed ratio. The invention allows substantially efficient combustion throughout the engine operating map. Various methods of changing the charge of air are disclosed.

A method for controlling an internal combustion engine provides that the internal combustion engine is operated based on a first injection pattern in a first operating state, and based on a second injection pattern in a second operating state. At least one parameter of the injection patterns in the transition from the first to the second operating state is selected in such a way that the noise emission remains constant. In the transition to the injection pattern having greater noise, first the at least one parameter of the first injection pattern is varied, whereupon the switchover takes place. In the transition to the injection pattern having the lower noise, first the switchover is implemented, whereupon the at least one parameter of the second injection pattern is varied.