An engine control apparatus includes 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 the 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 the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be higher when an engine speed is high than when the engine speed is low.

A control device of an engine including a cylinder, a piston, a cylinder head, and a combustion chamber is provided, which includes intake and exhaust ports, a swirl control valve provided in an intake passage connected to the intake port, a fuel injection valve attached to the cylinder head to be oriented into the center of the combustion chamber in a plan view thereof, and having first and second nozzle ports, and a control unit. The control unit includes a processor configured to execute a swirl opening controlling module to output the control signal to the swirl control valve to have a given opening at which a swirl ratio inside the combustion chamber becomes 2 or above, and a fuel injection timing controlling module to output the control signal to the fuel injector to inject fuel at a given timing at which the swirl ratio becomes 2 or above.

A control method of an internal combustion engine including a spark plug and a fuel injection valve includes starting electric discharge of the spark plug after a gas flow in a direction from a side of the fuel injection valve toward a side of the spark plug is generated at a position of an electric discharge gap of the spark plug due to spray of the fuel injected from the fuel injection valve.

A method for determining the cylinder air-charge of an internal combustion engine in a non-fired operation, wherein a method for determining the cylinder air-charge in a fired operation is performed. According to the invention, provision is made that in the method for determining the cylinder air-charge in the fired operation, a correction factor is provided as a function of engine speed and engine load which adjusts the value of the cylinder air-charge determined by the method in the fired operation to the non-fired operation. Thus, the previously known methods can be improved and made more efficient, in particular in view of the deviations of up to 30% between the cylinder air-charge values in the non-fired operation and the modeled values of the fired operation.

An auxiliary chamber (51) having a spark plug (54) and an auxiliary fuel injector is formed at the central part of the top surface of the main combustion chamber (2). When making an air-fuel mixture in the auxiliary chamber (51) burn by the spark plug (54), an air-fuel mixture in the main combustion chamber (2) is made to burn by jet flames ejected from the communicating holes (52). The injection ports of the auxiliary fuel injector (53) are oriented toward a tumble flow inflow peripheral region (R) which is located on the peripheral part of the end portion of the auxiliary chamber (51) at a place located on a side where the tumble flow W flows in from the communicating holes (52). When the tumble flow (W) is made to be generated in the main combustion chamber (2) by the tumble flow control valve (48), auxiliary fuel (QF) is injected from the auxiliary fuel injector (53) toward the tumble flow inflow peripheral region (R) of the auxiliary chamber (51).

The engine control method includes a fuel supply step and an ignition step. In the fuel supply step, the injector supplies fuel into a combustion chamber. In the ignition step, an spark plug arranged in the combustion chamber makes a flame after the supply of the fuel into the combustion chamber and at a timing when a flow strength in the combustion chamber is greater than a predetermined value in a compression stroke during or before a post-mid stage where the compression stroke is divided into four stages of a pre-stage, a pre-mid stage, a post-mid stage, and a post-stage.

An engine control method includes: a first fuel supply step of supplying fuel into the combustion chamber using an injector when a spark plug makes flame in the combustion chamber so that an air-fuel mixture is generated at least around the spark plug, the air-fuel mixture having an air-fuel mass ratio A/F or a gas-fuel mass ratio G/F, in which gas includes air, higher than a stoichiometric air-fuel ratio; after the first fuel supply step, an ignition step of making the flame in the combustion chamber in the compression stroke using the spark plug; and after the ignition step, a second fuel supply step of supplying the fuel into the combustion chamber in the compression stroke using the injector to increase a fuel concentration of the air-fuel mixture in the combustion chamber.

An air intake apparatus of an internal combustion engine includes an intake passage, an intake air flow control valve, a housing portion configured to house the intake air flow control valve, a swirl opening arranged at a first side of the intake air flow control valve to generate swirl, and a tumble opening arranged at a second side of the intake air flow control valve to generate tumble. The swirl opening is provided at one of the intake air flow control valve and a portion between the intake passage and the intake air flow control valve, the tumble opening being provided at the other of the intake air flow control valve and the portion between the inner surface of the intake passage and the intake air flow control valve. The intake air flow control valve rotates to achieve a switching between a swirl state and a tumble state.

In an internal combustion engine which performs a homogeneous lean combustion mode and a stratified lean combustion mode, there is provided a new internal combustion engine control device capable of obtaining a stable combustion state by decreasing influences of delay of an air flow and a degree of change of a transient state and smoothly performing switching between the homogeneous lean combustion mode and the stratified lean combustion mode. Accordingly, in the present invention, when switching between the stratified lean mode in which a compression stroke injection is performed by a direct injection injector 7 and the homogeneous lean combustion mode in which an intake stroke injection is performed by the direct injection injector 7 is performed, a predetermined delay time t is provided from at least a switching operation of a tumble control valve 6, a switching operation between the compression stroke injection and the intake stroke injection is performed, and the delay time t is set so as to correspond to a magnitude of the degree of change L of the transient state. A switching timing between the compression stroke injection and the intake stroke injection is controlled according to the flow delay of an air control system such as the tumble control valve 6 and the degree of change L of the transient state, and thus, it is possible to improve combustion stability in a combustion chamber.

A control strategy includes: after an engine is energized, the continuously variable valve lift mechanism self learning to determine a current position; if the self learning is successful, the continuously variable valve lift mechanism being located at a maximum lift position, preparing for starting the engine, and determining a regulating mode based on a starting temperature, wherein at the time of normal temperature start, regulation is performed from the maximum lift position to a minimum lift position, and at the time of low temperature start, regulation is performed from the maximum lift position to a position where the two valves for the same cylinder have a maximum lift difference; if the self learning fails, entering a preliminary start mode; entering a CVVL control mode based on an operation condition of the engine; and powering off the engine.