Patent ID: 6192310
Filing Date: 2001-02-20
Classification: F02D

Abstract:
A device for diagnosis of the condition of a nonlinear sensor disposed upstream from a catalytic converter associated with a fuel injected internal combustion engine controlled by an electronic computer, the engine containing a first control loop, including said nonlinear sensor, to deliver to the computer a first signal for correction of a quantity of fuel injected, and a second control loop, including a second nonlinear sensor disposed downstream from the catalytic converter, to deliver a second signal for correction of the quantity of fuel injected, said diagnostic device comprising:a filter circuit to which there is applied the second correction signal in order to deliver a filtered signal,a measuring circuit to which there is applied an output of the upstream sensor in order to determine the mean value of the period of correction of the first control loop, anda logic circuit to determine, as a function of the values of the filtered signal and of the mean period, whether the condition of the upstream sensor is good or defective.