Catalyst Deterioration Detection Device
AssigneeToyota Jidosha Kabushiki Kaisha
InventorHiroshi Sawada
Life of this patent
Estimating the term…
Abstract
A catalyst deterioration detector not causing false detection of catalyst deterioration by eliminating the influence of a variation of the state of the gas at the catalyst outlet on the oxygen storage amount. Setting the lean target A/F to afL1 and the rich target A/F to afR1, the maximum oxygen storage amount Cmax1 is calculated (step 106). Next, setting the lean target A/F to afL2 and the rich target A/F to afR2, the maximum oxygen storage amount Cmax2 is calculated (step 108). Lastly, setting the lean target A/F to afL3 and the rich target A/F to afR3, the maximum oxygen storage amount Cmax3 is calculated (step 110). If these all calculated maximum oxygen storage amounts Cmax1, Cmax2, Cmax3 are less than a reference value Cmaxth, catalyst deterioration is detected (step 116).
Claims13
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control means, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation means, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection means, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation means.
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control means, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation means, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection means, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation means;
- wherein the air-fuel ratio control means performs at least a control operation for switching to a lean side air-fuel ratio and a rich side air-fuel ratio with reference to a particular air-fuel ratio and a control operation for switching to a lean side air-fuel ratio and a rich side air-fuel ratio with reference to an air-fuel ratio other than the particular air-fuel ratio.
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control means, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation means, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection means, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation means;
- wherein the air-fuel ratio control means exercises control for switching to a plurality of lean side air-fuel ratios and rich side air-fuel ratios with reference to a stoichiometric air-fuel ratio, the plurality of lean side air-fuel ratios and rich side air-fuel ratios being different in the degree of deviation from the stoichiometric air-fuel ratio.
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control unit, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation unit, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection unit, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation unit.
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control unit, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation unit, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection unit, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation unit;
- wherein the air-fuel ratio control unit performs at least a control operation for switching to a lean side air-fuel ratio and a rich side air-fuel ratio with reference to a particular air-fuel ratio and a control operation for switching to a lean side air-fuel ratio and a rich side air-fuel ratio with reference to an air-fuel ratio other than the particular air-fuel ratio.
A catalyst deterioration detection device that detects catalyst deterioration by exercising active control for switching an exhaust air-fuel ratio prevailing upstream of a catalyst between a lean side and a rich side, the catalyst deterioration detection device comprising:
- an exhaust gas sensor, which is installed downstream of the catalyst to vary the output value in accordance with an exhaust air-fuel ratio prevailing downstream of the catalyst;
- air-fuel ratio control unit, which exercises control to set the exhaust air-fuel ratio prevailing upstream of the catalyst at a plurality of different lean side air-fuel ratios and rich side air-fuel ratios;
- oxygen storage amount calculation unit, which calculates the oxygen excess/deficiency amount of an inflow to the catalyst before a change in the output value of the exhaust gas sensor at each of the plurality of different lean side air-fuel ratios and rich side air-fuel ratios, and calculates the oxygen storage amount of the catalyst in accordance with the oxygen excess/deficiency amount;
- and
- deterioration detection unit, which detects the deterioration of the catalyst in accordance with a plurality of oxygen storage amounts calculated by the oxygen storage amount calculation unit;
- wherein the air-fuel ratio control unit exercises control for switching to a plurality of lean side air-fuel ratios and rich side air-fuel ratios with reference to a stoichiometric air-fuel ratio, the plurality of lean side air-fuel ratios and rich side air-fuel ratios being different in the degree of deviation from the stoichiometric air-fuel ratio.
Dependencies are inferred from the claim text.