Fuel based engine operation control

A method for an engine, comprising:

• operating the engine with a variable cylinder fuel blend that varies a peak achievable engine torque for a given condition;
• selectively adjusting a cylinder valve timing to adjust an internal EGR amount at the given operating condition;
• and
• extending the valve timing adjustment to higher engine torques as the peak engine torque for the given operating condition increases, the internal EGR amount increasing as the peak torque increases.

A method of operating an engine in a vehicle, the method comprising:

• operating the engine with a variable fuel blend in a cylinder, where the variable fuel blend varies a peak achievable engine torque for a given operating condition to thereby provide a variable sized available engine torque range;
• selectively operating an engine actuator that affects engine torque and engine fuel economy at the given operating condition;
• and
• phasing the engine actuator in and out of operation differently over the variable peak achievable torque range responsive to a current fuel blend, wherein phasing the actuator in and out of operation includes adjusting a timing of a variable valve actuator to phase in internal EGR as a torque threshold is reached and phasing out internal EGR as the peak achievable torque is reached, and where the phasing out internal EGR begins at a higher torque as the peak torque increases.

A method of operating an engine in a vehicle, the method comprising:

• operating the engine with a variable fuel blend in a cylinder including injecting the variable fuel blend via a direct injector, where the variable fuel blend varies a peak achievable engine torque for a given operating condition to thereby provide a variable sized available engine torque range;
• selectively operating an engine actuator that affects engine torque and engine fuel economy at the given operating condition, the actuator including variable cylinder valve timing that adjusts internal EGR;
• and
• phasing the engine actuator in and out of operation differently over the variable peak achievable torque range responsive to a current fuel blend, where engine actuator operation at mid torque levels is maintained independent from changes in the fuel blend.