Adaptive torque model for internal combustion engine

A method for controlling a multi-cylinder internal combustion engine, the method comprising:

• determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises:
• estimating engine torque for current operating conditions;
• estimating load torque for current operating conditions;
• and
• determining an estimated engine speed based on the estimated engine torque and estimated load torque;
• measuring a second engine operating variable using an associated sensor;
• and
• modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation, wherein the estimated engine speed is periodically reset to actual engine speed as determined by an engine speed sensor.

A method for controlling a multi-cylinder internal combustion engine, the method comprising:

• determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises:
• estimating engine torque for current operating conditions;
• estimating load torque for current operating conditions;
• and
• determining an estimated engine speed based on the estimated engine torque and estimated load torque;
• measuring a second engine operating variable using an associated sensor;
• and
• modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation, wherein the multi-cylinder internal combustion engine is a direct injection spark ignition engine having a plurality of combustion modes of operation and wherein the estimated engine speed is periodically reset to the actual engine speed at each change of combustion mode of operation.

A method for controlling a multi-cylinder internal combustion engine, the method comprising:

• determining a first engine operating variable using a model having at least one adjustable model parameter, wherein the step of determining a first engine operating variable comprises:
• estimating engine torque for current operating conditions;
• estimating load torque for current operating conditions;
• and
• determining an estimated engine speed based on the estimated engine torque and estimated load torque;
• measuring a second engine operating variable using an associated sensor;
• modifying at least one adjustable model parameter based on a relationship between the first and second engine operating variables to adapt the model for variations in engine operation;
• determining an actual engine speed using an engine speed sensor;
• comparing the actual engine speed to the estimated engine speed to determine an engine speed difference;
• and
• resetting the estimated engine speed to the actual engine speed when the engine speed difference exceeds a corresponding threshold.