Control method and apparatus for adaptively determining a fuel pulse width

A method for controlling an amount of fuel delivered to a cylinder of an internal combustion engine, said method comprising:

• determining a first amount of fuel to deliver to said cylinder based on a current air charge of said cylinder and a desired air-fuel ratio;
• calculating a first air-fuel ratio change value based on an amount of change in said air charge;
• calculating a second air-fuel ratio change value based on an amount of change in purge flow to said cylinder;
• and,
• delivering a second amount of fuel to said cylinder based on said first amount of fuel, and said first and second air-fuel ratio change values.

A control system for controlling the operation of an engine having an exhaust gas sensor and air charge sensor, said system comprising:

• a feed-forward controller determining an overall fuel pulse width as a function of an air charge change, and a purge flow change;
• a feedback controller coupled to the exhaust gas oxygen signal, for determining pulse width correction in response to the oxygen signal;
• and
• a summing block coupled to the feed forward controller and the feedback controller, said summing block generating an adjusted fuel pulse width as a function of said overall fuel pulse width and said pulse width correction.

An article of manufacture comprising a computer storage medium having a computer program encoded therein for controlling an engine of an automotive vehicle, said computer storage medium comprising:

• code for determining a first amount of fuel to deliver to said cylinder based on a current air charge of said cylinder and a desired air-fuel ratio;
• code for calculating a first air-fuel ratio change value based on an amount of change in said air charge;
• code for calculating a second air-fuel ratio change value based on an amount of change in purge flow to said cylinder;
• and,
• code for delivering a second amount of fuel to said cylinder based on said first amount of fuel, and said first and second air-fuel ratio change values.