Method and system for controlling an engine with enhanced torque control

A computer readable storage media having stored data representing instructions to control an engine, the computer readable storage media comprising:

• instructions for establishing a torque correction coefficient to compensate for reducing effect of available engine torque in operating range of different excess air ratios lower than a predetermined value;
• instructions for determining an initial base desired in-cylinder air mass based on a requested engine torque;
• instructions for determining a desired excess air ratio;
• instructions for adjusting said initial base desired in-cylinder air mass with at least said desired excess air ratio and said torque correction coefficient to generate a desired in-cylinder air mass;
• and
• instructions for determining a desired injected fuel mass based on said desired in-cylinder air mass for fuel injection to deliver said requested engine torque with said desired excess air ratio held accomplished.

A system for controlling an engine, comprising:

• a plurality of sensors for sensing a plurality of operating parameters of the engine;
• and
• an ECU having control logic operative
• to establish a torque correction coefficient to compensate for reducing effect of available engine torque in operating range of different excess air ratios that are lower than a predetermined value;
• to determine an initial base desired in-cylinder air mass based on a requested engine torque;
• to determine a desired excess air ratio;
• to adjust said initial base desired in-cylinder air mass with at least said desired excess air ratio and said torque correction coefficient to generate a desired in-cylinder air mass;
• and
• to determine a desired injected fuel mass based on said desired in-cylinder air mass for fuel injection to deliver said requested engine torque with said desired excess air ratio held accomplished.

A system for controlling an engine, comprising:

• means for establishing a torque correction coefficient to compensate for reducing effect of available engine torque in operating range of different excess air ratios that are lower than a predetermined value;
• means for determining an initial base desired in-cylinder air mass based on a requested engine torque;
• means for determining a desired excess air ratio;
• means for adjusting said initial base desired in-cylinder air mass with at least said desired excess air ratio and said torque correction coefficient to generate a desired in-cylinder air mass;
• and
• means for determining a desired injected fuel mass based on said desired in-cylinder air mass for fuel injection to deliver said requested engine torque with said desired excess air ratio held accomplished.