| 摘要 |
<p>PROBLEM TO BE SOLVED: To simply estimate the current amount of oxygen stored in an exhaust emission control catalyst, and control it to be an amount suitable for eliminating harmful matter.SOLUTION: With reference to an output signal from an air-fuel ratio sensor 43 installed upstream of a catalyst 41, the partial pressure of oxygen in exhaust gas upstream of the catalyst is estimated, and with reference to an output signal from an air-fuel ratio sensor 44 installed downstream of the catalyst, the partial pressure of oxygen in exhaust gas downstream of the catalyst is estimated. On the basis of a difference between both partial pressures of the oxygen, the amount of oxygen stored in the catalyst or released from the catalyst is estimated, and then a fuel injection amount is adjusted to be increased/reduced to converge the current amount of the oxygen stored in the catalyst to a target value.</p> |
