| 摘要 |
PROBLEM TO BE SOLVED: To improve the accuracy of estimating the oxygen storage capacity of a catalyst under a reduced pressure.SOLUTION: A control device for an internal combustion engine utilizes a period from forcibly varying an air-fuel ratio on the upstream side of the exhaust gas purifying catalyst mounted in an exhaust passage of the internal combustion engine to actualizing a variation in the air-fuel ratio on the upstream side, to estimate the oxygen storage capacity of the catalyst. The control device changes the characteristics of a relationship between an output signal from an air-fuel ratio sensor for detecting the air-fuel ratio of gas flowing into the catalyst and the air-fuel ratio of the gas, depending the levels of the atmospheric pressure in this case, and then acquires the air-fuel ratio of the gas from the output signal from the air-fuel ratio sensor. It uses the air-fuel ratio of the gas to estimate the oxygen storage capacity of the catalyst.SELECTED DRAWING: Figure 2 |
