Methods, systems, and devices for managing motor torque smoothing for internal combustion engine cylinder recharging events are described herein. An engine controller in a vehicle for managing motor torque smoothing for internal combustion engine cylinder recharging events may be configured to operate the internal combustion engine at a firing fraction that is less than a value of 1.0, wherein one or more cylinders are not designated to be fired, determine a recharge event time period where a particular one of the cylinders that have not been designated to be fired is recharged, identify a disruption quantity of torque during the recharging event time period, and actuate an additional motor to initiate a supplemental quantity of torque during the recharge event time period based on the disruption quantity of torque.

A method for entering and exiting cylinder deactivation modes in a diesel engine, comprises monitoring an engine speed from an idle engine speed to a governed engine speed and monitoring an engine load. If the monitored engine speed is the idle engine speed up to the governed engine speed, and if the engine load is less than the predetermined low load condition, then implementation of a cylinder deactivation mode is restricted to one of a 2 cylinder deactivation mode, a 3 cylinder deactivation mode, or a 4 cylinder deactivation mode. A cylinder deactivation mode is selected for engine operation among the 2 cylinder deactivation mode, the 3 cylinder deactivation mode, and the 4 cylinder deactivation mode to operate the engine at an effective frequency that avoids two resonant frequencies of the vehicle and to operate the engine below a torsional vibration limit.

Methods and systems are provided for an engine for adjusting cylinder parameter settings to optimize engine output during a transient mode. In one example, a method may include adjusting cylinder parameter settings, including a cam timing setting, a spark timing setting, and a fuel injection timing setting based on a chamber temperature in response to a rate of fuel injection acceleration being greater than a positive threshold, thus indicating the engine is in the transient mode.

Methods and systems are provided for reducing emissions during an engine cold start. In one example, a method may include, during emission control device heating, injecting heated air into an exhaust runner of each cylinder of the engine during an exhaust stroke of the corresponding cylinder, after a blowdown exhaust pulse. In this way, an amount of hydrocarbons in feedgas provided to the emission control device prior to the emission control device reaching its light-off temperature may be reduced.

The invention is provided with an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Timing of the preceding ignition is more advanced when a swirl flow is gentle than when the swirl flow is strong.

A method of reducing cold start emissions in a series mode hybrid electric vehicle, including an internal combustion engine with an exhaust duct having a catalyst and a downstream oxygen sensor, an output of the combustion engine being connected to an electric generator with a power output of at least 10 kW that is connected to an electric motor which is coupled to a drive shaft of two or more wheels. The method includes detecting a cold start condition, injecting fuel into the engine such that combustion at a lambda value, λ, is achieved for which λ>1, running the engine at a speed of 1000 rpm or higher, determining if the efficiency of the catalyst reaches a first level, setting λ to about 1 after the predetermined efficiency level of the catalyst has been reached, and reducing the speed to working conditions when the catalyst efficiency reaches a second level.

Methods and systems are provided for reducing emissions during an engine cold start. In one example, a method may include, during emission control device heating, injecting heated air into an exhaust runner of each cylinder of the engine during an exhaust stroke of the corresponding cylinder, after a blowdown exhaust pulse. In this way, an amount of hydrocarbons in feedgas provided to the emission control device prior to the emission control device reaching its light-off temperature may be reduced.

A stop control device for an internal combustion engine is structured that stops the engine in a state suitable for starting and that does not cause a crank angle to change after the engine is stopped. A four-cycle internal combustion engine includes an electric valve opening and closing timing control device that sets an opening and closing timing of either or both of an intake valve and an exhaust valve. Stop control of stopping the internal combustion engine is performed when a stop signal for stopping the internal combustion engine is acquired, and post-stop phase control of displacing the opening and closing timing of the valve opening and closing timing control device in either an advancing direction or a retarding direction is performed after the internal combustion engine is stopped by the stop control.

A variety of methods and arrangements for reducing noise, vibration and harshness (NVH) in a skip fire engine control system are described. In one aspect, a firing sequence is used to operate the engine in a skip fire manner. A smoothing torque is determined that is applied to a powertrain by an energy storage/release device. The smoothing torque is arranged to at least partially cancel out variation in torque generated by the skip fire firing sequence. Various methods, powertrain controllers, arrangements and computer software related to the above operations are also described.

Systems and methods for estimating an engine event location are disclosed herein. In one embodiment, a control system is configured to receive feedback from at least one vibration sensor coupled to a reciprocating engine, estimate an engine parameter based at least on the feedback and an Empirical Transform Function (ETF), estimate a location of an engine event based on the engine parameter, and adjust operation of the reciprocating engine based at least on the location of the engine event.