Engine fuel injection control system

A method of controlling a fuel injection quantity of an engine comprising:

• detecting an operating condition of an engine;
• providing a particulate filter in an exhaust passage of the engine to accumulate exhaust particulate matter discharged from the engine;
• comparing an accelerator request fuel quantity corresponding to an accelerator depression amount with an air fuel ratio request fuel injection quantity determined based on a target air fuel ratio corresponding to the engine operating condition;
• selecting a smaller one of the accelerator request fuel quantity and the air fuel ratio request fuel injection quantity as a target fuel injection quantity;
• and
• adjusting the target air fuel ratio to a value substantially equal to an air fuel ratio that provides a maximum torque when the engine is operating in a low rotational speed with a full-load condition.

An engine fuel injection control system comprising:

• operating condition detecting means for detecting an operating condition of an engine;
• particulate accumulating means for accumulating exhaust particulate matter contained in an exhaust gas discharged from the engine in an exhaust passage of the engine;
• fuel injection quantity determining means for comparing an accelerator request fuel quantity corresponding to an accelerator depression amount with an air fuel ratio request fuel injection quantity determined based on a target air fuel ratio corresponding to the engine operating condition, and selecting a smaller one of the accelerator request fuel quantity and the air fuel ratio request fuel injection quantity as a target fuel injection quantity;
• and
• target air fuel ratio adjusting means for adjusting the target air fuel ratio to a value substantially equal to an air fuel ratio that provides a maximum torque when the operating condition detecting means detects the engine is operating in a low rotational speed with a full-load condition.