In a catalyst warming-up control, a first time injection is performed by an injector in an intake stroke. A second time injection is performed with an amount smaller than the first time injection in an expansion stroke after a compression top dead center. In the catalyst warming-up control, an interval from the start of the ignition period of an spark plug to the completion of the second time injection is controlled by the ECU so that the initial flame generated from an air-fuel mixture containing the fuel spray injected by the first time injection is brought into contact with the fuel spray injected by the second time injection.

An engine system is provided, which includes a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, and a subspark plug that ignites the mixture gas inside the subchamber, an throttle valve, and a control device. In a first range, compression self-ignition combustion of the mixture gas inside the main combustion chamber is performed. In a second range, flame propagation combustion is performed while setting an air-fuel ratio of the mixture gas lower than that in the first range. Immediately after the transition from the first range to the second range, only the subignition is performed, or the subignition and the main ignition are performed while setting a timing of the main ignition to a timing same as or retarded from the subignition.

An engine system is provided, which includes a main combustion chamber, a subchamber, an injector that injects fuel into the main combustion chamber, a main spark plug that ignites a mixture gas inside the main combustion chamber, and a subspark plug that ignites the mixture gas inside the subchamber, an throttle valve, and a control device. In a first range, compression self-ignition combustion of the mixture gas inside the main combustion chamber is performed. In a second range, flame propagation combustion is performed while setting an air-fuel ratio of the mixture gas lower than that in the first range. Immediately after the transition from the first range to the second range, only the subignition is performed, or the subignition and the main ignition are performed while setting a timing of the main ignition to a timing same as or retarded from the subignition.

Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.

Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.

Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.

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.

An engine control method includes a step of setting combustion mode in which a first combustion mode in which a mixed gas is combusted by propagating flame or a second combustion mode in which the mixed gas is combusted by self-ignition is selected, a step of setting air-fuel ratio mode in which a lean first air-fuel ratio mode or a second air-fuel ratio mode equal to or richer than a theoretical air-fuel ratio is selected, a step of setting torque reduction in which a torque reduction amount by which a torque generated by an engine is reduced based on a steer angle of a steering wheel, and a suppressing step in which reducing the torque generated by the engine based on the torque reduction amount set in the step of setting torque reduction is suppressed.

A variety of methods and arrangements are described for managing transitions between operational states of an internal combustion engine during skip fire operation of the engine.

Methods, devices, estimators, controllers and algorithms are described for estimating the torque profile of an engine and/or for controlling torque applied to a powertrain by one or more devices other than the engine itself to manage the net torque applied by the engine and other device(s) in manners that reduce undesirable NVH. The described approaches are particularly well suitable for use in hybrid vehicles in which the engine is operated in a skip fire or other dynamic firing level modulation manner—however they may be used in a variety of other circumstances as well. In some embodiments, the hybrid vehicle includes a motor/generator that applies the smoothing torque.