Abstract: A variety of methods and arrangements are described for managing recharging of cylinders of an internal combustion engine during skip fire operation of the engine. In one method, a maximum allowed deactivation time for a cylinder is determined and the cylinder is recharged before the maximum allowed deactivation time is exceeded.

Abstract: A variety of methods and arrangements are described for managing recharging of cylinders of an internal combustion engine during skip fire operation of the engine. In one method, a maximum allowed deactivation time for a cylinder is determined and the cylinder is recharged before the maximum allowed deactivation time is exceeded.

Abstract: A variety of engine controllers and methods are described for controlling engines operating in a cylinder output level modulation mode. In one aspect transitions between different effective firing fractions are managed by gradually ramping an effective firing density. In another, when an engine transitions to a multi-level skip fire firing density that has more than one possible high/low/skip sequence, the phase of the high/low pattern is set relative to the phase of the firing pattern to ensure that a preferred high/low/skip sequence is generated. In another aspect, rapid large torque changes can be implemented in part by immediately changing the operational high/low fraction in response to a command to increase or reduce the desired engine torque.

Abstract: A variety of engine controllers and methods are described for controlling engines operating in a cylinder output level modulation mode. In one aspect transitions between different effective firing fractions are managed by gradually ramping an effective firing density. In another, when an engine transitions to a multi-level skip fire firing density that has more than one possible high/low/skip sequence, the phase of the high/low pattern is set relative to the phase of the firing pattern to ensure that a preferred high/low/skip sequence is generated. In another aspect, rapid large torque changes can be implemented in part by immediately changing the operational high/low fraction in response to a command to increase or reduce the desired engine torque.

Abstract: The present invention relates generally to improving the fuel efficiency of autonomous vehicles by operating either (1) at a first effective engine displacement that takes into account noise, vibration and harshness (NVH) when the vehicle is occupied or (2) at a second effective engine displacement, without concern for occupant NVH, when the vehicle is not occupied. The second effective engine displacement is typically more fuel efficient than the first effective engine displacement, but result in a higher level of NVH compared to the first effective engine displacement.

Abstract: The present invention relates generally to improving the fuel efficiency of autonomous vehicles by operating either (1) at a first effective engine displacement that takes into account noise, vibration and harshness (NVH) when the vehicle is occupied or (2) at a second effective engine displacement, without concern for occupant NVH, when the vehicle is not occupied. The second effective engine displacement is typically more fuel efficient than the first effective engine displacement, but result in a higher level of NVH compared to the first effective engine displacement.