Control system for controlling internal combustion engine

A control system for controlling an internal combustion engine which discharges exhaust gases through an emission purifier, comprising:

• intake air quantity control means for increasing the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling for quickly activating the emission purifier after the internal combustion engine has started to operate, to a level which is greater by a predetermined increase than the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling normally;
• means for establishing the predetermined increase depending on the engine temperature of the internal combustion engine;
• and
• ignition timing control means for generating a command value for ignition timing of the internal combustion engine according to a feedback control process to converge the rotational speed of the internal combustion engine toward a predetermined target rotational speed, and for controlling the ignition timing of the internal combustion engine based on the generated command value thereby to retard the ignition timing,
• wherein said intake air quantity control means comprises means for correcting said predetermined increase so as to reduce the quantity of intake air when said command value for ignition timing generated by said ignition timing generated by said ignition timing control means according to the feedback control process becomes more retarded than a predetermined threshold, which is established in a retarded range, within an allowable range of ignition timing in which said internal combustion engine can operate normally,
• wherein said intake air quantity control means comprises means for progressively increasing a corrective quantity by which said predetermined increase is corrected so as to reduce the quantity of intake air, when said command value for ignition timing generated by said ignition timing control means according to the feedback control process is more retarded than said predetermined threshold, and
• wherein said intake air quantity control means comprises means for holding said corrective quantity by which said predetermined increase is corrected so as to reduce the quantity of intake air, to a present corrective quantity when said command value for ignition timing generated by said ignition timing control means according to the feedback control process is changed so as to be more advanced than said predetermined threshold, when said predetermined increase is corrected so as to reduce the quantity of intake air.

A control system for controlling an internal combustion engine which discharges exhaust gases through an emission purifier, comprising:

• intake air quantity control means for increasing the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling for quickly activating the emission purifier after the internal combustion engine has started to operate, to a level which is greater by a predetermined increase than the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling normally;
• means for establishing the predetermined increase depending on the engine temperature of the internal combustion engine;
• and
• ignition timing control means for generating a command value for ignition timing of the internal combustion engine according to a feedback control process to converge the rotational speed of the internal combustion engine toward a predetermined target rotational speed, and for controlling the ignition timing of the internal combustion engine based on the generated command value thereby to retard the ignition timing,
• wherein said intake air quantity control means comprises means for correcting said predetermined increase so as to reduce the quantity of intake air when said command value for ignition timing generated by said ignition timing control means according to the feedback control process becomes more retarded than a predetermined threshold, which is established in a retarded range, within an allowable range of ignition timing in which said internal combustion engine can operate normally, and
• wherein said ignition timing control means comprises means for generating the command value for ignition timing of the internal combustion engine according to a proportional plus integral control process as said feedback control process, and controlling the ignition timing of the internal combustion engine with a retarded limit of the allowable range of ignition timing and holding the value of an integral term of the proportional plus integral control process to a present value when the generated command value becomes more retarded than said retarded limit of the allowable range of ignition timing.

A control system for controlling an internal combustion engine which discharges exhaust gases through an emission purifier, comprising:

• intake air quantity control means for increasing the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling for quickly activating the emission purifier after the internal combustion engine has started to operate, to a level which is greater by a predetermined increase than the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling normally;
• means for establishing the predetermined increase depending on the engine temperature of the internal combustion engine;
• ignition timing control means for generating a command value for ignition timing of the internal combustion engine according to a feedback control process to converge the rotational speed of the internal combustion engine toward a predetermined target rotational speed, and for controlling the ignition timing of the internal combustion engine based on the generated command value thereby to retard the ignition timing, and
• decision means for deciding whether or not the increasing of the quantity of intake air with said intake air quantity control means and the controlling of the ignition timing of the internal combustion engine with said ignition timing control means are to be canceled, based on an operating state of the internal combustion engine, wherein said intake air quantity control means and said ignition timing control means are disabled if the increasing of the quantity of intake air with said intake air quantity control means and the controlling of the ignition timing of the internal combustion engine with said ignition timing control means are to be canceled as decided by said decision means, and
• wherein said intake air quantity control means comprises means for immediately stopping increasing the quantity of intake air when the increasing of the quantity of intake air is to be canceled as decided by said decision means, and said ignition timing control means comprises means for progressively advancing the ignition timing which has been retarded according to the feedback control process when the controlling of the ignition timing is to be canceled as decided by said decision means.

A control system for controlling an internal combustion engine which discharges exhaust gases through an emission purifier, comprising:

• intake air quantity control means for increasing the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling for quickly activating the emission purifier after the internal combustion engine has started to operate, to a level which is greater by a predetermined increase than the quantity of intake air drawn into the internal combustion engine while the internal combustion engine is idling normally;
• means for establishing the predetermined increase depending on the engine temperature of the internal combustion engine;
• ignition timing control means for generating a command value for ignition timing of the internal combustion engine according to a feedback control process to converge the rotational speed of the internal combustion engine toward a predetermined target rotational speed, and for controlling the ignition timing of the internal combustion engine based on the generated command value thereby to retard the ignition timing, and
• decision means for deciding whether or not the increasing of the quantity of intake air with said intake air quantity control means and the controlling of the ignition timing of the internal combustion engine with said ignition timing control means are to be canceled, based on an elapsed time in which the quantity of intake air increased by said intake air quantity control means, wherein said intake air quantity control means and said ignition timing control means are disabled if the increasing of the quantity of intake air with said intake air quantity control means and the controlling of the ignition timing of the internal combustion engine with said ignition timing control means are to be canceled as decided by said decision means,
• wherein said intake air quantity control means comprises means for immediately stopping increasing the quantity of intake air when the increasing of the quantity of intake air is to be canceled as decided by said decision means, and said ignition timing control means comprises means for progressively advancing the ignition timing which has been retarded according to the feedback control process when the controlling of the ignition timing is to be canceled as decided by said decision means.