Catalytic converter efficiency monitoring
Patent 5157919 Issued on October 27, 1992. Estimated Expiration Date: 
July 22, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 22, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInternal combustion exhaust catalytic reactor monitoring system Fuel control system with calibration learning capability for motor vehicle internal combustion engine Method and apparatus for monitoring and adjusting λ-probe-controlled catalytic exhaust gas emission control systems of internal combustion engines Patent #: 4622809 InventorAssigneeApplicationNo. 733932 filed on 07/22/1991US Classes:60/274, Anti-pollution60/276, Having means analyzing composition of exhaust gas60/277Having sensor or indicator of malfunction, unsafeness, or disarray of treater (e.g., fusible link, etc.)ExaminersPrimary: Hart, DouglasAttorney, Agent or FirmInternational ClassF01N 003/20AbstractAn on-board catalytic converter efficiency monitoring system uses an exhaust gas oxygen sensor downstream of a converter to enable closed loop air-fuel ratio control. The period of the air-fuel limit cycle is used to determine a time constant parameter of the feedback loop. A parameter in the fuel controller is changed to induce another air-fuel limit cycle frequency. The period of this new air-fuel limit cycle provides additional information with respect to the time constant of the feedback loop. Because it is possible to make other changes to the parameters of the fuel controller, different frequencies can be induced and additional parameters of the feedback loop time constant can be determined. With n different frequencies produced by n different fuel controller parameters it is possible to solve for n different time constants. The system can be used with either one or two EGO sensors depending upon the desired parameter to be solved. It is particularly advantageous to use one EGO sensor downstream of a converter to determine the catalytic efficiency. | |
