SYSTEM OF INTERNAL COMBUSTION ENGINE DIAGNOSTICS Russian patent published in 2017 - IPC F02D45/00 

FIELD: engines and pumps.

SUBSTANCE: internal combustion engine is composed of exhaust gas purification catalyst (20), and air-fuel ratio sensor (41), positioned on the outlet side of the exhaust gas purification catalyst, it reduces or stops the fuel supply by means of the fuel cut-off control and controls the air-fuel ratio of the exhaust gas, adjusting it to a rich air-fuel ratio after completing the fuel cut-off control by way of the rich restart control. The diagnostic system calculates the first characteristic of the air-fuel ratio change at the time, when the air-fuel ratio output first passes through the first X air-fuel ratio area, that is poorer than the stoichiometric air-fuel ratio and the second air-fuel ratio change characteristic in the time, when the output air-fuel ratio first passes through the second area of the Y air-fuel ratio, including the stoichiometric air-fuel ratio. The diagnostic system diagnoses an abnormal operation mode of the air-fuel ratio sensor, based on the first characteristic of the change in the air-fuel ratio and the second characteristic of the change in the air-fuel ratio. As a result, it is possible to eliminate the consequences of the change in the state of the exhaust gas purification catalyst and at the same time accurately diagnose the abnormal deteriorated response of the air-fuel ratio sensor from the exhaust side.

EFFECT: providing a diagnostic system that diagnoses deterioration in the air-fuel ratio sensor characteristics.

21 cl, 14 dwg