Patent Document ID: 20050022797
Application ID: 10901087
Patent Status: 0

Claim One:
1. A cylinder-by-cylinder air-fuel ratio calculation apparatus for a multi-cylinder internal combustion engine in which the cylinder-by-cylinder air-fuel ratio calculation apparatus is applied for the multi-cylinder internal combustion engine including plural exhaust passages leading to respective cylinders and being collected, and an air-fuel ratio sensor disposed at an exhaust collective part, and calculates a cylinder-by-cylinder air-fuel ratio on the basis of a sensor detection value of the air-fuel ratio sensor, comprising: a unit for creating a model in which the sensor detection value of the air-fuel ratio sensor is made one obtained by multiplying a history of a cylinder-by-cylinder air-fuel ratio of an inflow gas in the exhaust collective part and a history of the sensor detection value by specified weights respectively and by adding them, and for estimating the cylinder-by-cylinder air-fuel ratio on the basis of the model.