Internal EGR quantity estimation, cylinder intake air quantity calculation, valve timing control, and ignition timing control

A method for an engine, the method comprising:

• obtaining information on an exhaust valve closing timing, an intake valve opening timing and an engine speed;
• and
• calculating an estimated internal EGR quantity of the engine in accordance with the exhaust valve closing timing, the intake valve opening timing and the engine speed.

An apparatus comprising:

• an internal EGR quantity estimating section to calculate an estimated internal EGR quantity of an engine in accordance with an exhaust valve closing timing, an intake valve opening timing and an engine speed of the engine.

An apparatus for an engine, the apparatus comprising:

• means for collecting information on an exhaust valve closing timing, an intake valve opening timing and an engine speed of the engine;
• and
• means for calculating an estimated internal EGR quantity of the engine in accordance with the exhaust valve closing timing, the intake valve opening timing and the engine speed.