Abstract: Disclosed is a supercharged direct-injection engine, which comprises a supercharging device (25, 30) for compressing intake air, and an injector 10 for directly injecting fuel into a combustion chamber 5. In the engine, an excess air factor ? as a ratio of an actual air-fuel ratio to a stoichiometric air-fuel ratio, at least in an engine warmed-up mode, is set to 2 or more in the entire engine-load region. Further, compressed self-ignited combustion is performed in a low engine-load region, and a supercharging amount by the supercharging device (25, 30) is increased along with an increase in engine load in a high engine-load region to allow the excess air factor ? to be kept at 2 or more. The engine of the present invention can effectively reduce NOx emission, while improving fuel economy.

Abstract: Various systems and methods are disclosed for controlling an internal combustion engine system having an internal combustion engine, and a fuel injector which directly injects fuel into a combustion chamber of the internal combustion engine. One example method comprises, when a desired torque for the internal combustion engine system is in a first range, injecting a first stage fuel into the combustion chamber so that it ends during a middle stage of a compression stroke at the latest in a cylinder cycle; determining combustion of the first stage fuel initiated by its compression self-ignition; and injecting a second stage fuel into the combustion chamber in a period when the determined combustion of the first stage fuel continues at a timing determined so as to cause combustion of the second stage fuel with its compression self-ignition.

Abstract: Various systems and methods are disclosed for controlling an internal combustion engine system having an internal combustion engine, a fuel injector which directly injects fuel into a combustion chamber of the internal combustion engine, and a supercharger which supercharges air into the combustion chamber. One example method comprises, injecting fuel into the combustion chamber multiple times so that a first part of the fuel is self ignited and a last part of the fuel being injected during the compression stroke or later in a cylinder cycle when a desired torque of said internal combustion engine system is in a first range; and increasing a pressure of air which the supercharger charges into the combustion chamber as amount of fuel injected into the combustion chamber during a cylinder cycle increases when the desired torque is in the first range.

Abstract: There is provided, in one aspect of the present description, a method of controlling a spark ignited internal combustion engine having a fuel injector which injects fuel directly into its combustion chamber. The method comprises stopping the fuel injection if a desired torque for the engine is a predetermined torque or less and a speed of the engine is a predetermined speed or greater. The method comprises resuming the fuel injection by injecting a first amount of fuel directly into the combustion chamber during a negative pressure period and injecting a second amount of the fuel into the combustion chamber during an intake period. The method further includes resuming the fuel injection by injecting a third amount of the fuel directly into the combustion chamber during the negative pressure period and injecting a fourth amount of the fuel into the combustion chamber during the intake period.

Abstract: There is provided a method for starting a spark ignition engine having multiple cylinders. The method may comprise supplying air and fuel for restart into a first cylinder before said engine completely stops, and igniting the mixture of said air and said fuel in said first cylinder in response to an engine restart request, wherein said first cylinder is on an expansion stroke when said engine stops. The method may also include, after said piston in said first cylinder starts moving, injecting fuel into a second cylinder that is on a compression stroke when said engine stops, on a compression stroke where a piston of said second cylinder is moving in a direction opposite to an operative direction of said piston in said first cylinder.

Abstract: There is provided a method of starting a spark ignition engine having multiple cylinders. The method comprises supplying air and fuel for restart into a first cylinder before the engine completely stops, and igniting the mixture of the air and the fuel in the first cylinder in response to an engine start request. In accordance with the method, by supplying air and fuel into the first cylinder before the engine completely stops, the mixture of air and fuel in the first cylinder may be homogeneous at the time of the engine start request. Also, there may be less mixture turbulence and combustion may propagate better within the cylinder. These conditions may reduce the rate of combustion in the first cylinder after a start request is initiated. The slower combustion rate may decrease temperature of the combusted gas while the cylinder wall temperature is relatively low because the engine has stopped.

Abstract: For the purpose of improving the fuel efficiency by lean combustion and enhancing the fuel efficiency improvement effects by performing compression ignition efficiently in some cylinders, a multi-cylinder spark ignition engine is constructed such that exhaust gas, that is exhausted from preceding cylinders 2A, 2D on the exhaust stroke side among pairs of cylinders whose exhaust stroke and intake stroke overlap in a low load, low rotational speed region, is directly introduced through an inter-cylinder gas passage 22 into following cylinders 2B, 2C on the intake stroke side and only gas exhausted from the following cylinders 2B, 2C is fed to an exhaust passage 20, which is provided with a three-way catalyst 24.

Abstract: There is provided a method of starting a spark ignition engine having multiple cylinders. The method comprises supplying air and fuel for restart into a first cylinder before the engine completely stops, and igniting the mixture of the air and the fuel in the first cylinder in response to an engine start request. In accordance with the method, by supplying air and fuel into the first cylinder before the engine completely stops, the mixture of air and fuel in the first cylinder may be homogeneous at the time of the engine start request. Also, there may be less mixture turbulence and combustion may propagate better within the cylinder. These conditions may reduce the rate of combustion in the first cylinder after a start request is initiated. The slower combustion rate may decrease temperature of the combusted gas while the cylinder wall temperature is relatively low because the engine has stopped.

Abstract: When an engine restart request is given in an engine stopping period which begins at a point of fuel supply interruption and ends at a point of complete engine stop, an engine starting system judges whether TDC engine speed detected immediately before is equal to or lower than a specific value “A”, the counted number of reverse running motions of the engine is 0, and a piston in an expansion stroke cylinder is relatively close to TDC. If the judgment result is in the affirmative with all these conditions satisfied, the engine starting system injects fuel into the expansion stroke cylinder and then ignites and combusts a mixture produced therein. The engine starting system also injects the fuel into a compression stroke cylinder and then ignites and combusts a mixture produced therein when a piston in the compression stroke cylinder has gone beyond TDC.

Abstract: A direct-injection spark-ignition engine includes a spark plug provided approximately at the center of the ceiling of a combustion chamber, and an injector having at its downstream end a nozzle which is located in an upper peripheral area of the combustion chamber, in which multiple openings are formed in the nozzle of the injector. Fuel is injected from the nozzle of the injector directly toward the proximity of an electrode of the spark plug. The directions of axis lines of the individual openings are set such that central points of fuel jets spewed out of the individual openings do not lie on the spark plug but are distributed around the electrode, slightly separated therefrom.

Abstract: A control device switches an engine between normal operation mode and special operation mode. In the normal operation mode, an independent cylinder configuration is formed to produce combustion independently in individual cylinders. In the special operation mode, a two-cylinder interconnect configuration is formed so that burned gas discharged from preceding cylinders currently in an exhaust stroke is introduced into following cylinders currently in an intake stroke through intercylinder gas channels, a lean mixture having a high air-fuel ratio is combusted in the preceding cylinders, and a mixture produced by supplying fuel to the burned gas is combusted in the following cylinders.

Abstract: When an engine restart request is given in an engine stopping period which begins at a point of fuel supply interruption and ends at a point of complete engine stop, an engine starting system judges whether TDC engine speed detected immediately before is equal to or lower than a specific value “A”, the counted number of reverse running motions of the engine is 0, and a piston in an expansion stroke cylinder is relatively close to TDC. If the judgment result is in the affirmative with all these conditions satisfied, the engine starting system injects fuel into the expansion stroke cylinder and then ignites and combusts a mixture produced therein. The engine starting system also injects the fuel into a compression stroke cylinder and then ignites and combusts a mixture produced therein when a piston in the compression stroke cylinder has gone beyond TDC.

Abstract: A control device switches an engine between normal operation mode and special operation mode. In the normal operation mode, an independent cylinder configuration is formed to produce combustion independently in individual cylinders. In the special operation mode, a two-cylinder interconnect configuration is formed so that burned gas discharged from preceding cylinders currently in an exhaust stroke is introduced into following cylinders currently in an intake stroke through intercylinder gas channels, a lean mixture having a high air-fuel ratio is combusted in the preceding cylinders, and a mixture produced by supplying fuel to the burned gas is combusted in the following cylinders.

Abstract: For the purpose of improving the fuel efficiency by lean combustion and enhancing the fuel efficiency improvement effects by performing compression ignition efficiently in some cylinders, a multi-cylinder spark ignition engine is constructed such that exhaust gas, that is exhausted from preceding cylinders 2A, 2D on the exhaust stroke side among pairs of cylinders whose exhaust stroke and intake stroke overlap in a low load, low rotational speed region, is directly introduced through an inter-cylinder gas passage 22 into following cylinders 2B, 2C on the intake stroke side and only gas exhausted from the following cylinders 2B, 2C is fed to an exhaust passage 20, which is provided with a three-way catalyst 24.

Abstract: A direct-injection spark-ignition engine includes a spark plug provided approximately at the center of the ceiling of a combustion chamber, and an injector having at its downstream end a nozzle which is located in an upper peripheral area of the combustion chamber, in which multiple openings are formed in the nozzle of the injector. Fuel is injected from the nozzle of the injector directly toward the proximity of an electrode of the spark plug. The directions of axis lines of the individual openings are set such that central points of fuel jets spewed out of the individual openings do not lie on the spark plug but are distributed around the electrode, slightly separated therefrom.

Abstract: During stratified-charge combustion operation of a direct-injection spark ignition engine, at the cylinder compression stroke, a tumble is generated which flows between a spark plug electrode and a piston crown surface toward an injector. A fuel is injected from the injector in correspondence with the cylinder ignition timing by controlling the penetration of fuel spray from the injector to correspond to the tumble flow rate so that the fuel spray may go against the tumble, become a flammable mixture at the cylinder ignition timing and stay near the spark plug electrode. In the late stage of the compression stroke, diffusion of the flammable mixture is suppressed with squishes. Thus, fuel spray behavior in the combustion chamber is controlled to allow suitable mixture stratification over a wide engine operating condition range. This improves combustion quality and extends a stratified-charge combustion zone thereby providing enhanced fuel economy and power output.

Abstract: In the case that an engine is operated in a state where an in-cylinder air/fuel ratio is lean in a stratified combustion region and a fuel cut control is performed under a predetermined condition, when catalysts are in a low temperature state where a purification performance is deteriorated or when a NOx absorptive amount of the lean NOx catalyst, a control procedure for exhaust air/fuel state at a recovery timing from the fuel cut control so that a driving sensation is improved while maintaining the exhaust purification performance by the catalysts. When the fuel cut control is terminated and the engine shifts into the stratified combustion region, if a catalyst temperature is at or below a set temperature or a NOx absorptive amount is at or above a set amount, the in-cylinder air/fuel ratio of the engine is correctively enriched and the exhaust air/fuel state is enriched.

Abstract: In steps S25 to S42, in order to activate an inactive catalyst earlier, the air-fuel ratio in a combustion chamber is set to be &lgr;≈1 during a period T1 after engine start until catalyst light-off at around 50% HC purifying ratio immediately after the HC purifying ratio begins to rapidly rise, before the catalyst warms up, divisional injection is made at least during the period T1 required until light-off is reached, and a swirl is weakened during the period T1 compared to a latter period which follows this period T1. The divisional injection is made and the swirl is strengthened even during the latter period.

Abstract: During stratified-charge combustion operation of a direct-injection spark ignition engine, at the cylinder compression stroke, a tumble is generated which flows between a spark plug electrode and a piston crown surface toward an injector. A fuel is injected from the injector in correspondence with the cylinder ignition timing by controlling the penetration of fuel spray from the injector to correspond to the tumble flow rate so that the fuel spray may go against the tumble, become a flammable mixture at the cylinder ignition timing and stay near the spark plug electrode. In the late stage of the compression stroke, diffusion of the flammable mixture is suppressed with squishes. Thus, fuel spray behavior in the combustion chamber is controlled to allow suitable mixture stratification over a wide engine operating condition range. This improves combustion quality and extends a stratified-charge combustion zone thereby providing enhanced fuel economy and power output.

Abstract: A fuel injection control system for a direct injection-spark ignition type of engine forcibly turns off appliances as an external engine load while the engine operates in a stratified charge combustion mode after warming-up so as thereby to fix a quantity of intake air approximately constant and concurrently feedback controls a quantity of fuel injection according to an engine speed so as to bring the engine speed into a specified idling speed. An actual quantitative variation of fuel injection is learned on the basis of a feedback correction value of the quantity of fuel injection for each of predetermined fuel injection timings which are changed from a timing for minimum advance for best torque (MBT) so as to correspond to injection pulse widths within a region adopted for a micro-flow characteristic of the fuel injector.