Method of throttle fuel lean-out for internal combustion engines

A method of throttle fuel lean-out for an internal combustion engine, said method comprising the steps of:

• sensing a throttle position of a throttle for the engine with a throttle position sensor;
• calculating a delta throttle value by subtracting an instantaneous sensed throttle position value from a time averaged sensed throttle position value;
• determining whether the engine is in a throttle deceleration condition based on the calculated delta throttle value;
• determining a first value from a relative mass airflow surface as a function of a time averaged sensed throttle position and current engine speed, determining a second value from the relative mass airflow surface as a function of current instantaneous sensed throttle position and current engine speed, and subtracting the second value from the first value to obtain a delta relative mass airflow value if the calculated delta throttle value is positive if the engine is in a throttle deceleration condition;
• calculating a throttle deceleration fuel lean-out multiplier value multiplying the delta relative mass airflow value with a predetermined throttle lean-out multiplier value to obtain the throttle deceleration fuel lean-out value;
• and
• applying the calculated throttle deceleration fuel lean-out multiplier value to a fuel pulsewidth value of fuel injectors for the engine and reducing the amount of fuel injected into the engine by the fuel injectors.

A method of throttle fuel lean-out for an internal combustion engine, said method comprising the steps of:

• sensing a throttle position of a throttle for the engine with a throttle position sensor;
• calculating a delta throttle value by subtracting an instantaneous sensed throttle position value from a time averaged sensed throttle position value;
• determining whether the engine is in a throttle deceleration condition based on the calculated delta throttle value;
• linearizing the change in throttle position with respect to absolute throttle position and engine speed if the engine is in a throttle deceleration condition;
• calculating a throttle deceleration fuel lean-out multiplier value based on the linearized change in throttle position;
• and
• applying the calculated throttle deceleration fuel lean-out multiplier value to a fuel pulsewidth value of fuel injectors for the engine and reducing the amount of fuel injected into the engine by the fuel injectors.