Estimation device for cylinder intake air amount in an internal combustion engine

An estimation device for a cylinder intake air amount in an internal combustion engine,

• which serves for estimating an amount of intake air sucked into a cylinder in the internal combustion engine (1) which is connected to an intake pipe at a location downstream of a throttle valve (4), said estimation device comprising:
• a volumetric efficiency corresponding value calculation unit (22, 22A) that calculates a volumetric efficiency corresponding value (Kv) which is an index indicating an amount of air coming into said cylinder from said intake pipe;
• and
• a cylinder intake air amount estimation unit (21, 21A) that estimates an amount of air actually sucked into said cylinder by using said volumetric efficiency corresponding value (Kv);
• wherein said volumetric efficiency corresponding value calculation unit (22, 22A) calculates said volumetric efficiency corresponding value (Kv) based on an exhaust efficiency (Kex), which is an index indicating an amount of residual gas which is an exhaust gas after combustion remaining in said cylinder without being discharged into an exhaust pipe from the interior of said cylinder, and an intake efficiency (Kin), which is an index indicating an amount of air which comes into said cylinder from said intake pipe except for said amount of residual gas.