Abstract: In one aspect, a skip fire engine controller is described. The skip fire engine controller includes a skip fire module arranged to determine an operational firing fraction and associated cylinder load for delivering a desired engine output. The skip fire engine controller also includes a firing controller arranged to direct firings in a skip fire manner that delivers the selected operational firing fraction. Various methods, modules, lookup tables and arrangements related to the selection of a suitable operational firing fraction are also described.

Abstract: In one aspect, a skip fire engine controller is described. The skip fire engine controller includes a skip fire module arranged to determine an operational firing fraction and associated cylinder load for delivering a desired engine output. The skip fire engine controller also includes a firing controller arranged to direct firings in a skip fire manner that delivers the selected operational firing fraction. Various methods, modules, lookup tables and arrangements related to the selection of a suitable operational firing fraction are also described.

Abstract: In one aspect, a skip fire engine controller is described. The skip fire engine controller includes a skip fire module arranged to determine an operational firing fraction and associated cylinder load for delivering a desired engine output. The skip fire engine controller also includes a firing controller arranged to direct firings in a skip fire manner that delivers the selected operational firing fraction. Various methods, modules, lookup tables and arrangements related to the selection of a suitable operational firing fraction are also described.

Abstract: An engine sound enhancement system includes a conduit in communication with at least one of an intake manifold and an exhaust manifold of an engine. An interface is arranged at least one of within the conduit and between an inlet of the conduit and the at least one of the intake manifold and the exhaust manifold. The interface is responsive to pulses within the at least one of the intake manifold and the exhaust manifold, wherein the interface is configured to transfer the pulses into the conduit.

Abstract: A system according to the principles of the present disclosure includes a vibration prediction module and a firing sequence module. The vibration prediction module predicts a modal response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated. The firing sequence module adjusts the firing sequence of the engine based on the predicted modal response of the vehicle.

Abstract: An engine sound enhancement system includes a conduit in communication with at least one of an intake manifold and an exhaust manifold of an engine. An interface is arranged at least one of within the conduit and between an inlet of the conduit and the at least one of the intake manifold and the exhaust manifold. The interface is responsive to pulses within the at least one of the intake manifold and the exhaust manifold, wherein the interface is configured to transfer the pulses into the conduit.

Abstract: A firing module determines a target number of activated cylinders of an engine based on a torque request and a present gear ratio of a transmission. A combination identification module, based on the torque request, identifies a combination including a possible number of activated cylinders and a possible transmission gear ratio, wherein at least one of: the possible number of activated cylinders is different than the target number of activated cylinders; and the possible transmission gear ratio is different than the present gear ratio of the transmission.

Abstract: A system includes a cylinder control module that determines target numbers of cylinders of an engine to be activated during a period, determines, based on the target numbers and an engine speed, N predetermined sequences for controlling the cylinders of the engine during the period, determines whether a transition parameter is associated with at least one of the N predetermined subsequences and selectively adjusts at least one of the N predetermined subsequences based on the determination of whether a transition parameter is associated with at least two of the N predetermined sequences. The system further includes a cylinder actuator module that, during the period, controls the cylinders of the engine based on the N predetermined sequence and based on the at least one selectively adjusted predetermined sequences.

Abstract: Based on a desired average number of activated cylinders per sub-period of a predetermined period including P sub-periods, a cylinder control module selects one of N predetermined cylinder activation/deactivation patterns. The selected cylinder activation/deactivation pattern corresponds to Q activated cylinders per sub-period, Q is an integer between zero and a total number of cylinders of an engine, inclusive, P is an integer greater than one, and the desired average number of active cylinders is a number between zero and the total number of cylinders of the engine.

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 target cylinder count module determines a target number of cylinders of an engine to be activated during a future period. The future period includes N sub-periods, and N is an integer greater than one. Based on the target number, a first sequence setting module generates a sequence indicating N target numbers of cylinders to be activated during the N sub-periods, respectively. A second sequence setting module retrieves N predetermined sequences for activating and deactivating cylinders during the N sub-periods, respectively, and generates a target sequence for activating and deactivating cylinders during the future period based on the N predetermined sequences. During the future period, a cylinder actuator module: activates opening of intake and exhaust valves of the cylinders that are to be activated based on the target sequence; and deactivates opening of intake and exhaust valves of the cylinders that are to be deactivated based on the target sequence.

Abstract: A firing module determines a target number of activated cylinders of an engine based on a torque request and a present gear ratio of a transmission. A combination identification module, based on the torque request, identifies a combination including a possible number of activated cylinders and a possible transmission gear ratio, wherein at least one of: the possible number of activated cylinders is different than the target number of activated cylinders; and the possible transmission gear ratio is different than the present gear ratio of the transmission.

Abstract: A cylinder control module generates a desired cylinder activation/deactivation sequence for a future period based on Q predetermined cylinder activation/deactivation sub-sequences used during a previous period, a desired number of cylinders to be activated during a predetermined period including the previous and future periods, and an operating condition. Q is an integer greater than zero. The cylinder control module activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated and deactivated based on the desired cylinder activation/deactivation sequence, respectively. A fuel control module provides and disables fuel to the first and second ones of the cylinders, respectively.

Abstract: A system includes a cylinder control module that determines target numbers of cylinders of an engine to be activated during a period, determines, based on the target numbers and an engine speed, N predetermined sequences for controlling the cylinders of the engine during the period, determines whether a transition parameter is associated with at least one of the N predetermined subsequences and selectively adjusts at least one of the N predetermined subsequences based on the determination of whether a transition parameter is associated with at least two of the N predetermined sequences. The system further includes a cylinder actuator module that, during the period, controls the cylinders of the engine based on the N predetermined sequence and based on the at least one selectively adjusted predetermined sequences.

Abstract: A system according to the principles of the present disclosure includes a vibration prediction module and a firing sequence module. The vibration prediction module predicts a vibration response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated. The firing sequence module adjusts the firing sequence of the engine based on the predicted vibration response of the vehicle.

Abstract: In one aspect, a skip fire engine controller is described. The skip fire engine controller includes a skip fire module arranged to determine an operational firing fraction and associated cylinder load for delivering a desired engine output. The skip fire engine controller also includes a firing controller arranged to direct firings in a skip fire manner that delivers the selected operational firing fraction. Various methods, modules, lookup tables and arrangements related to the selection of a suitable operational firing fraction are also described.

Abstract: A target cylinder count module determines a target number of cylinders of an engine to be activated during a future period. The future period includes N sub-periods, and N is an integer greater than one. Based on the target number, a first sequence setting module generates a sequence indicating N target numbers of cylinders to be activated during the N sub-periods, respectively. A second sequence setting module retrieves N predetermined sequences for activating and deactivating cylinders during the N sub-periods, respectively, and generates a target sequence for activating and deactivating cylinders during the future period based on the N predetermined sequences. During the future period, a cylinder actuator module: activates opening of intake and exhaust valves of the cylinders that are to be activated based on the target sequence; and deactivates opening of intake and exhaust valves of the cylinders that are to be deactivated based on the target sequence.

Abstract: A system according to the principles of the present disclosure includes a vibration prediction module and a firing sequence module. The vibration prediction module predicts a vibration response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated. The firing sequence module adjusts the firing sequence of the engine based on the predicted vibration response of the vehicle.

Abstract: A cylinder control module generates a desired cylinder activation/deactivation sequence for a future period based on Q predetermined cylinder activation/deactivation sub-sequences used during a previous period, a desired number of cylinders to be activated during a predetermined period including the previous and future periods, and an operating condition. Q is an integer greater than zero. The cylinder control module activates and deactivates opening of intake and exhaust valves of first and second ones of the cylinders that are to be activated and deactivated based on the desired cylinder activation/deactivation sequence, respectively. A fuel control module provides and disables fuel to the first and second ones of the cylinders, respectively.

Abstract: A system according to the principles of the present disclosure includes a vibration prediction module and a firing sequence module. The vibration prediction module predicts a modal response of a vehicle based on a firing sequence of an engine when a cylinder of the engine is deactivated. The firing sequence module adjusts the firing sequence of the engine based on the predicted modal response of the vehicle.