Patent ID: 8676472

Claim:
An atmospheric pressure estimating apparatus having atmospheric pressure estimating means for estimating a first atmospheric pressure applied to a calculation of control parameters of an internal combustion engine, said atmospheric pressure estimating apparatus being characterized by comprising: intake pressure detecting means for detecting an intake pressure of said engine; intake air control valve passing air flow rate detecting means for detecting a flow rate of air passing through an intake air control valve of said engine; and control valve opening detecting means for detecting an opening of the intake air control valve, wherein said atmospheric pressure estimating means includes: flow rate estimating means for calculating an estimated intake air control valve passing air flow rate based on a second atmospheric pressure for flow rate estimation, the intake pressure, and the intake air control valve opening; updating means for updating a third atmospheric pressure for estimating calculation so that the estimated intake air control valve passing air flow rate coincides with the detected intake air control valve passing air flow rate; first averaging calculation means for calculating a first averaged estimated atmospheric pressure by averaging the third atmospheric pressure updated by said updating means; and second averaging calculation means for calculating a second averaged estimated atmospheric pressure by averaging the first averaged estimated atmospheric pressure, wherein said flow rate estimating means calculates the estimated intake air control valve passing air flow rate using the first averaged estimated atmospheric pressure as the second atmospheric pressure, and said atmospheric pressure estimating means calculates the second averaged estimated atmospheric pressure as the first atmospheric pressure.