Control system and method and engine control unit for internal combustion engine

A control method for an internal combustion engine of an in-cylinder fuel injection type, the engine being operated while switching a combustion mode thereof between a homogeneous combustion mode in which fuel injection into each cylinder is performed during an intake stroke, a stratified combustion mode in which the fuel injection into the cylinder is performed during a compression stroke, and a two-stage fuel injection combustion mode in which the fuel injection into the cylinder is performed once during the intake stroke and once during the compression stroke during transition between the homogeneous combustion mode and the stratified combustion mode,

• the control method comprising the steps of:
• calculating a demanded torque which is demanded of the engine;
• detecting a rotational speed of the engine;
• determining, based on the calculated demanded torque, which of the homogeneous combustion mode, the stratified combustion mode, and the two-stage fuel injection combustion mode should be selected as the combustion mode;
• and
• determining an amount of fuel to be injected during the compression stroke in the two-stage fuel injection combustion mode, based on the detected rotational speed of the engine.

A control system for an internal combustion engine of an in-cylinder fuel injection type, the engine being operated while switching a combustion mode thereof between a homogeneous combustion mode in which fuel injection into each cylinder is performed during an intake stroke, a stratified combustion mode in which the fuel injection into the cylinder is performed during a compression stroke, and a two-stage fuel injection combustion mode in which the fuel injection into the cylinder is performed once during the intake stroke and once during the compression stroke during transition between the homogeneous combustion mode and the stratified combustion mode, the control system comprising;

• a demanded torque-calculating module for calculating a demanded torque which is demanded of the engine;
• an engine rotational speed-detecting module for detecting a rotational speed of engine;
• a combustion mode-determining module for determining, based on the calculated demanded torque, which of the homogeneous combustion mode, the stratified combustion mode, and the two-stage fuel injection combustion mode should be selected as the combustion mode;
• a total fuel injection amount determining module for determining a total amount of fuel to be injected in the two-stage fuel injection combustion mode;
• a compression stroke fuel injection amount determining module for determining an amount of fuel to be injected during the compression stroke in the two-stage fuel injection combustion mode, based on the detected rotational speed of the engine;
• and
• an intake stroke fuel injection amount-determining module for determining an amount of fuel to be injected during the intake stroke in the two-stage fuel injection combustion mode, based on the determined total fuel injection amount and the determined intake stroke fuel injection amount.

A control method for an internal combustion engine of an in-cylinder fuel injection type, the engine being operated while switching a combustion mode thereof between a homogeneous combustion mode in which fuel injection into each cylinder is performed during an intake stroke, a stratified combustion mode in which the fuel injection into the cylinder is performed during a compression stroke, and a two-stage fuel injection combustion mode in which the fuel injection into the cylinder is performed once during the intake stroke and once during the compression stroke during transition between the homogeneous combustion mode and the stratified combustion mode, the control method comprising the steps of;

• calculating a demanded torque which is demanded of the engine;
• detecting a rotational speed of engine;
• determining, based on the calculated demanded torque, which of the homogeneous combustion mode, the stratified combustion mode, and the two-stage fuel injection combustion mode should be selected as the combustion mode;
• determining a total amount of fuel to be injected in the two-stage fuel injection combustion mode;
• determining an amount of fuel to be injected during the compression stroke in the two-stage fuel injection combustion mode, based on the detected rotational speed of the engine;
• and
• determining an amount of fuel to be injected during the intake stroke in the two-stage fuel injection combustion mode, based on the determined total fuel injection amount and the determined intake stroke fuel injection amount.

An engine control unit including a control program for causing a computer to carry out control for an internal combustion engine of an in-cylinder fuel injection type, the engine being operated while switching a combustion mode thereof between a homogeneous combustion mode in which fuel injection into each cylinder is performed during an intake stroke, a stratified combustion mode in which the fuel injection into the cylinder is performed during a compression stroke, and a two-stage fuel injection combustion mode in which the fuel injection into the cylinder is performed once during the intake stroke and once during the compression stroke during transition between the homogeneous combustion mode and the stratified combustion mode,

• wherein the control program causes the computer to calculate a demanded torque which is demanded of the engine, detect a rotational speed of engine, determine, based on the calculated demanded torque, which of the homogeneous combustion mode, the stratified combustion mode, and the two-stage fuel injection combustion mode should be selected as the combustion mode, determine a total amount of fuel to be injected in the two-stage fuel injection combustion mode, determine an amount of fuel to be injected during the compression stroke in the two-stage fuel injection combustion mode, based on the detected rotational speed of the engine, and determine an amount of fuel to be injected during the intake stroke in the two-stage fuel injection combustion mode, based on the determined total fuel injection amount and the determined intake stroke fuel injection amount.