Methods and systems are provided for improving the performance of a variable displacement engine. Split injection and spark retard may be used in active cylinder during a VDE mode to heat an exhaust catalyst and extend the duration of VDE mode operation. Split injection and spark retard may also be used in reactivated cylinders at a time of cylinder reactivation to improve restart combustion stability.

Additional approaches for the reduction of particulate emissions in gasoline engines using optimized port+direct injection are described. These embodiments include control of the amount of directly injected fuel so as to avoid a threshold increase in particulates due to piston wetting and reduction of cold start emissions by use of air preheating using variable valve timing.

An HT cooling system cools at least a cylinder block with HT cooling water. An LT cooling system cools an intake port with LT cooling water that is at a lower temperature than the HT cooling water. A controller performs an ignition retard control that involves correcting the ignition timing based on the result of detection of a knock by a knock sensor, and a cooling enhancement control that involves enhancing cooling by the LT cooling system in the case where a knock is detected compared with the case where no knock is detected. The way of cooling by the HT cooling system is unchanged whether a knock is detected.

A method for operating an internal combustion engine of a motor vehicle, where the internal combustion engine includes a combustion chamber and a prechamber spark plug which is assigned to the combustion chamber and which has a prechamber which is fluidically connected to the combustion chamber via a plurality of openings. The method includes operating the internal combustion engine in a catalytic converter heating operation in which an ignition time, at which an ignition spark for igniting a fuel-air mixture in the combustion chamber is generated in the prechamber within a particular operating cycle of the internal combustion engine, is shifted later compared to a normal operation. An injection time, at which a last direct fuel injection into the combustion chamber is carried out within the particular operating cycle, is a same in the catalytic converter heating operation and in the normal operation.

An electronic engine timing system that includes at least (1) an engine position sensor that includes a diametric magnet and two or more hall effect sensors configured and positioned to sense diametric magnet position, (2) sensor data receiving circuitry configured for receiving sensory input, including at least input from the engine position sensor; and (3) control circuitry configured to control firing of one or more cylinders of the engine at least in part by calculating one or more timing advance positions for one or more cylinders of the engine and by causing the one or more cylinders to fire according to the one or more calculated timing advance positions, the control circuitry further configured to calculate the one or more timing advance positions for the one or more cylinders separately from one another based at least in part on input from the engine position sensor.

A control device predicts whether temporary reduction occurs to a charging efficiency of fresh air in an in-cylinder gas by an influence of an EGR rate of the in-cylinder gas, which increases later than increase of a charging efficiency of the in-cylinder gas, if a first arithmetic operation is applied to calculating a target throttle opening degree based on a target charging efficiency which is increasing, in a case of shifting to an acceleration operation, by using a prediction model expressing dynamic characteristics of an internal combustion engine. When it is predicted that temporary reduction occurs to the charging efficiency of the fresh air, the control device calculates the target throttle opening degree by a second arithmetic operation by which an increase speed of a throttle opening degree is restrained more than by the first arithmetic operation, instead of calculating the target throttle opening degree by the first arithmetic operation.

An ignition system includes a dividing wall which divides a combustion chamber of an engine into a main chamber and a pre-chamber and has formed therein at least one spray hole which communicates between the main chamber and the pre-chamber, and a spark plug in which voltage is applied across a spark gap between a first electrode and a second electrode to create an electrical spark to ignite fuel. The pre-chamber has the first electrode. The dividing wall or a member which electrically conducts with the dividing wall has the second electrode. The ignition system executes an after-top-dead-center ignition control mode to ignite fuel after a compression stroke top dead center. In the after-top-dead-center ignition control mode, an ignition source which is in the form of a self-growable flame kernel is provided in a spray hole-nearby region, the spray hole, or the main chamber within a crank angle of 20° after an ignition timing at which the voltage starts to be applied across the spark gap. The spray hole-nearby region is a region which is located 3 mm or less away from a spray hole center in the pre-chamber.

To provide a controller for internal combustion engine which can suppress deterioration of the detection accuracy of the combustion state due to influence of the external disturbance component, when detecting a combustion state based on angle detection information by the crank angle sensor. A controller for internal combustion engine calculates a shaft torque in unburning; calculates an external load torque based on the shaft torque in unburning and the actual shaft torque in the vicinity of the top dead center; and in an integration crank angle interval which is set corresponding to a combustion period, calculates a subtraction value by subtracting the external load torque from the shaft torque in unburning, calculates a division value by dividing the subtraction value by the inertia moment, and calculates a combustion state index by integrating a value obtained by subtracting the division value from the crank angle acceleration.

To provide a controller for internal combustion engine which can suppress deterioration of the detection accuracy of the combustion state due to influence of the external disturbance component, when detecting a combustion state based on angle detection information by the crank angle sensor. A controller for internal combustion engine calculates a shaft torque in unburning; calculates an external load torque based on the shaft torque in unburning and the actual shaft torque in the vicinity of the top dead center; and in an integration crank angle interval which is set corresponding to a combustion period, calculates a subtraction value by subtracting the external load torque from the shaft torque in unburning, calculates a division value by dividing the subtraction value by the inertia moment, and calculates a combustion state index by integrating a value obtained by subtracting the division value from the crank angle acceleration.

A catalyst control system includes a stop and start module that, during a period that the vehicle is ON between (i) a first time when the vehicle is turned ON and (i) a second time when the vehicle is next turned OFF, selectively shuts down and starts a spark ignition engine of the vehicle. A catalyst light off (CLO) control module initiates a first CLO event for a first engine startup during the period and, when a temperature of a catalyst that receives exhaust output by the engine is less than a predetermined temperature, selectively initiates a second CLO event for a second engine startup during the period. A fuel control module richens fueling of the engine during the first and second CLO events of the period. A spark control module retards spark timing of the engine during the first and second CLO events of the period.