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.

A vehicle control system for an internal combustion engine having a fuel injection valve for injecting fuel directly into a combustion chamber includes a controller configured to perform a fuel cut-off when a predetermined fuel cut-off condition is met during travel of the vehicle to thereby stop fuel injection from the fuel injection valve. The controller is configured to resume the fuel injection from the fuel injection valve when a predetermined fuel cut-off recovery condition is met during the fuel cut-off. The controller is configured, upon elapse of a predetermined time that is required for a wall temperature of the combustion chamber to rise after resuming the fuel injection from the fuel injection valve, to perform a rich spike that temporarily increases the fuel injection amount from the fuel injection valve.

A control device for an internal combustion engine has a controller configured to control a fuel injection valve arranged to directly inject a fuel into a combustion chamber, and a variable compression ratio mechanism arranged to vary an upper dead center position of a piston, and thereby to vary a compression ratio of the internal combustion engine. The controller is configured to control a fuel cut by which the fuel injection from the fuel injection valve is stopped, when a predetermined fuel cut condition is satisfied during a traveling of a vehicle. The fuel injection from the fuel injection valve is restarted when a predetermined fuel cut recovery condition is satisfied during the fuel cut.

A control device for an internal combustion engine of a vehicle has a controller that controls a fuel injection valve of the internal combustion engine arranged to directly inject a fuel into a combustion chamber, and a pressure regulator of the internal combustion engine arranged to vary a pressure of the fuel supplied to the fuel injection valve. The controller performs a fuel cut that stops the fuel injection of the fuel injection valve when a predetermined fuel cut condition is satisfied during a traveling of the vehicle. The controller restarts the fuel injection of the fuel injection valve when a predetermined fuel cut recovery condition is satisfied during the fuel cut.

A control device for an internal combustion engine including an in-cylinder injection fuel injection valve, and a port injection fuel injection valve, has a controller that controls injection amount ratios of the in-cylinder injection fuel injection valve and the port injection fuel injection valve in accordance with a driving condition of the engine. A fuel cut is performed at a predetermined deceleration of the internal combustion engine. The injection amount ratio of the in-cylinder injection fuel injection valve is corrected to be decreased at a fuel cut recovery at which a fuel supply is restarted from the fuel cut state, during a predetermined period from the start of the recovery.

A method of controlling the fuel air mixture of an internal combustion engine following a cold restart includes determining a control parameter based on the value of current coolant temperature at time of current engine start, the value of coolant temperature at time of the previous engine start, a calibratable reference temperature, the total accumulated fuel mass injected during previous engine run time, the time the engine was off before the restart, and the time the engine was run after previous start. The method also includes controlling the fuel air mixture based on said control parameter.

The purpose of the present invention is to provide an engine control device with which it is possible to minimize decreases in combustion speed even when the EGR rate has been increased. The present invention is an engine control device for: controlling an engine provided with an injector for injecting fuel directly into a cylinder, an ignition device for igniting the injected fuel, and an EGR means capable of recycling combustion gas and varying the EGR rate of the recycling combustion gas; and commanding the injector to perform multiple injections during one cycle, wherein a command is given to perform a control for increasing the injection quantity per compression stroke relative to the total injection quantity in one cycle so that the injection quantity per compression stroke is greater when the EGR rate is high than when the EGR rate is low, and/or a control for increasing the number of injections per compression stroke relative to the total number of injections in one cycle so that the number of injections per compression stroke is greater when the EGR rate is high than when the EGR rate is low.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

In a control device for an internal combustion engine, when a fuel-supply cutoff process ends and fuel injection restarts, an increase ratio based on which a base injection amount is increased is set such that the increase ratio when a duration of the fuel-supply cutoff process is long is higher than the increase ratio when a duration of the fuel-supply cutoff process is short. In addition, the increase ratio is decreased with a lapse of time after fuel injection restarts. Further, a decrease rate that is an amount by which the increase ratio is decreased within a prescribed period of time is set such that the decrease rate in the case where the duration of the fuel-supply cutoff process is long is higher than the decrease rate in the case where the duration of the fuel-supply cutoff process is short.

Methods and systems are presented for adjusting an amount of fuel supplied to an engine via port and direct fuel injectors during transient engine operating conditions where the fuel injection amount is adjusted responsive to the transient engine operating conditions. In one example, a fuel injection amount is adjusted based on a time constant for a filter that is based on a direct fuel injection fuel fraction.