Engine cylinder induction air quantity measurement

An engine cylinder induction air quantity measuring process comprising:

• calculating an intake manifold inside air quantity, from a sensed intake air quantity of an engine, by performing a balance calculation to calculate a balance between an intake manifold inflow air quantity, and an intake manifold outflow air quantity, and calculating a cylinder induction air quantity from the intake manifold inside air quantity;
• determining whether an engine stop position of the engine is within a valve overlap period of the engine;
• and
• modifying the manifold inside air quantity by setting the manifold inside air quantity equal to an overlap stop mode final air quantity when the engine stop position is within the valve overlap period.

An engine cylinder induction air quantity measuring apparatus comprising:

• means for calculating an intake manifold inside air quantity by calculating a balance between an intake manifold inflow air quantity which is the mass of air flowing into an intake manifold of an engine and which is determined from an air flow rate sensed on an upstream side of the intake manifold, and an intake manifold outflow air quantity which is the mass of air flowing out of the intake manifold into a cylinder section of the engine, and calculating a cylinder induction air quantity from the intake manifold inside air quantity;
• means for detecting an engine stop of the engine;
• means for determining whether an engine stop position of the engine is within a valve overlap period of the engine when the engine stop is detected;
• and
• means for modifying the manifold inside air quantity by setting the manifold inside air quantity equal to an overlap stop mode quantity when the engine stop position is within the valve overlap period.