Abstract: A system and method for controlling an internal combustion engine employs a split injection to create stratified air/fuel mixture charge. The stratified charge includes an ignitable air/fuel mixture portion around a spark plug within the surrounding lean air/fuel mixture and experiences a two-stage combustion. The first stage is combustion of the ignitable air/fuel mixture portion initiated by a spark produced by the spark plug, providing an additional increase of cylinder pressure. The second stage is auto-ignited combustion of the surrounding lean air/fuel mixture induced by such additional cylinder pressure increase. The system and method also employ generating a combustion event indicative (CEI) parameter related with combustion speed or ignition timing point of auto-ignition of auto-ignited combustion of the surrounding mixture, and determining control parameters of a spark timing controller and a fuel supply controller in response to the CEI parameter.

Abstract: A fuel supply system has a fuel injector positioned to directly inject fuel into a combustion chamber, and it is capable of performing a split injection wherein a first fuel injection in each engine cycle precedes a second fuel injection that occurs during compression stroke in the same engine cycle. A spark plug produces a spark to ignite a first air/fuel mixture portion created due to the second fuel injection, initiating a first stage combustion. The first stage combustion raises temperature and pressure high enough to cause auto-ignition of a second air/fuel mixture portion surrounding the first air-fuel mixture portion, initiating a second stage combustion.

Abstract: An internal combustion engine is operated on auto-ignition combustion of fuel with low cetane number like gasoline. The engine has at least one cylinder and a reciprocating piston in the cylinder to define a combustion chamber. Combustion event in the cylinder is expressed in terms of two variables. They are main combustion timing (&thgr;50) and a main combustion period (&thgr;20-50). The main combustion timing (&thgr;50) represents a crank position when mass burnt rate is 50 percent. The main combustion period (&thgr;20-50) represents a period from a crank position when mass burnt is 20 percent to a crank position when mass burnt is 50 percent. Controlled parameters governing main combustion are varied to adjust the main combustion timing on an advance side of a retard limit (&thgr;50 max) and to adjust the main combustion period within a range between an upper limit (&thgr;20-50 max) and a lower limit (&thgr;20-50 min).

Abstract: In a compression self-ignition gasoline internal combustion engine, a fuel injector through which a gasoline fuel is injected uninterruptedly within a combustion chamber of an engine cylinder is provided, a mixture of air and gasoline fuel within the combustion chamber is self-ignited through a compression action of a piston, an intake valve an open timing of the intake valve is set to a mid-way point through a suction stroke of the piston, a closure timing of an exhaust valve is set to a mid-way point through an exhaust stroke thereof, and gasoline fuel injection timing and quantity per combustion cycle injected through the fuel injector is controlled in such a manner that a first gasoline fuel injection is set during a minus valve overlap time interval during which both of exhaust and intake valves are closed and a second gasoline fuel injection is set during at least one of the suction stroke and the subsequent compression stroke.

Abstract: A system and method for controlling an internal combustion engine employs a split injection to create stratified air/fuel mixture charge. The stratified charge includes an ignitable air/fuel mixture portion around a spark plug within the surrounding lean air/fuel mixture and experiences a two-stage combustion. The first stage is combustion of the ignitable air/fuel mixture portion initiated by a spark produced by the spark plug, providing an additional increase of cylinder pressure. The second stage is auto-ignited combustion of the surrounding lean air/fuel mixture induced by such additional cylinder pressure increase. The system and method also employ generating a combustion event indicative (CEI) parameter related with combustion speed or ignition timing point of auto-ignition of auto-ignited combustion of the surrounding mixture, and determining control parameters of a spark timing controller and a fuel supply controller in response to the CEI parameter.

Abstract: A system and method for enhanced combustion control in an internal combustion engine is disclosed. A fuel supply system has a fuel injector positioned to directly inject fuel into a combustion chamber, and it is capable of performing a split injection wherein a first fuel injection in each engine cycle precedes a second fuel injection that occurs during compression stroke in the same engine cycle. A spark plug produces a spark to ignite a first air/fuel mixture portion created due to the second fuel injection, initiating a first stage combustion. The first stage combustion raises temperature and pressure high enough to cause auto-ignition of a second air/fuel mixture portion surrounding the first air-fuel mixture portion, initiating a second stage combustion. An engine controller is programmed to perform control over initiation timing of the second stage combustion in response to at least one of the engine speed and load.

Abstract: An internal combustion engine is operated on auto-ignition combustion of fuel with low cetane number like gasoline. The engine has at least one cylinder and a reciprocating piston in the cylinder to define a combustion chamber. Combustion event in the cylinder is expressed in terms of two variables. They are main combustion timing (&thgr;50) and a main combustion period (&thgr;20-50). The main combustion timing (&thgr;50) represents a crank position when mass burnt rate is 50 percent. The main combustion period (&thgr;20-50) represents a period from a crank position when mass burnt is 20 percent to a crank position when mass burnt is 50 percent. Controlled parameters governing main combustion are varied to adjust the main combustion timing on an advance side of a retard limit (&thgr;50 max) and to adjust the main combustion period within a range between an upper limit (&thgr;20-50 max) and a lower limit (&thgr;20-50 min).

Abstract: Stroke cycles of a self-igniting gasoline engine (10) comprising an intake stroke, compression stroke, power stroke and exhaust stroke are performed sequentially by a piston (12), and self-ignition of the fuel mixture is performed by compression of the fuel mixture in the compression stroke. The strokes of the piston (12) are detected by a sensor (23), and an electronic control unit (1) controls a valve timing adjustment mechanism (15, 18) so that a sealed period occurs when both an exhaust valve (17) and intake valve (14) are closed in the vicinity of top dead center of the exhaust stroke. The electronic control unit (1) also controls the fuel injection timing of a fuel injector (19) so that fuel is injected into the combustion chamber (11) during the sealed period.

Abstract: A cylinder direct injection spark-ignition engine in which fuel is directly injected from a fuel injector into each cylinder. The engine has an intake system having two intake ports for each cylinder. A swirl control valve is movably disposed in a passage connected to one of the intake ports. The swirl control valve functions to regulate the intensity (a swirl ratio) of swirl to be generated in the cylinder. Sensors are provided to detect an engine operating condition representative of a stratified charge combustion region. Additionally, a controller is provided to control the swirl control valve so as to change the swirl ratio in accordance an engine speed of the engine, when the current engine operating condition is detected to correspond to the stratified charge combustion region.