The invention relates to a method for automatically detecting clogging of a sensor pipe extending between a pressure sensor and an exhaust manifold of an internal combustion engine, wherein the pressure sensor enables to record a signal representative of the relative pressure over time. The method includes at least one of the following steps: a) determining, while the engine runs in a steady operation state, an average amplitude of oscillations of the signal over a first period of time, the sensor pipe being considered clogged when said average amplitude is lower than a first threshold; b) monitoring, from the time the engine has been turned off, the signal over a second period of time, the sensor pipe being considered clogged when the integral of the signal is greater than a second threshold.

Methods, systems, and computer readable media are disclosed for providing a maintenance recommendation for a catalyst based on a trained machine learning model. The method includes: extract training data comprising one or more parameters from each catalyst of a plurality of catalysts: classify the training data in accordance with at least one catalyst feature at least one of the contaminations of the catalyst: determine a feature vector from the classified training data based on the one or more parameters extracted from catalyst of the plurality of catalysts, generate a performance baseline curve from the training data in accordance with the destruction removal efficiency (DRE) of a gas; and provide based on the trained machine learning model a maintenance recommendation for the catalyst.

Methods and systems are provided for diagnosing temperature sensors of a vehicle. In one example, a method may include, at a duration after an engine-off event, determining that an intake air temperature measured by an intake air temperature sensor of the vehicle is less than an ambient air temperature measured by an ambient air temperature sensor of the vehicle. In response to the determining, the method may include flowing air from a catalyst across the intake air temperature sensor; and indicating the intake air temperature sensor is functional responsive to the intake air temperature converging to the ambient air temperature during the flowing.

A controller for a vehicle includes failure diagnosis circuitry and drive control circuitry. The failure diagnosis circuitry is configured to perform a failure diagnosis of an internal combustion engine system while an internal combustion engine is in operation. The drive control circuitry is configured to operate the internal combustion engine in a charge depleting mode operation in which an electric motor mainly moves the vehicle while the internal combustion engine is not run only for charging a battery. The drive control circuitry is configured to run the internal combustion engine if a predetermined condition is satisfied in the charge depleting mode operation. The drive control circuitry is configured to continue running the internal combustion engine in order to perform the failure diagnosis even if the predetermined condition is unsatisfied while the internal combustion engine is run in the charge depleting mode operation.

A method, system, and apparatus are provided for improving accuracy of sensor readings reflecting measurements of at least one constituent in an engine exhaust. The sensor measurement is corrected or compensated for by applying to a gain correction factor to the reported sensor measurement. The gain correction factor is developed by determination of prior test sensor readings correlated with discrete sensor age levels, and with constituent concentrations to which those test sensors are exposed. By applying the determined gain correction factor to change the sensor's reported measurements, bias may be reduced and a more accurate measure of actual constituent levels is provided.

The invention relates to a method for monitoring a NOx sensor (10) having an oxygen-ion-conducting solid electrolyte and having at least one cavity (12), wherein at least one cavity (12) of the NOx sensor is flooded with a defined oxygen concentration during a self-diagnosis of the NOx sensor. The gradient of a pump current resulting therefrom is evaluated and, in the case of a deviation in comparison with reference values, possibly impaired dynamics of the NOx sensor are inferred.

A catalyst deterioration detection system 1 comprises an air-fuel ratio sensor 41, a current detection device 61, a voltage application device 60, a voltage control part 71, an air-fuel ratio control part 72 and a deterioration judging part 73. The air-fuel ratio control part executes fuel cut control, and, after the fuel cut control, executes rich control. The voltage control part, if judging that the air-fuel ratio of the outflowing exhaust gas has reached the stoichiometric air-fuel ratio when setting the applied voltage to a first voltage in a limit current region during the rich control, changes the applied voltage from the first voltage to a second voltage in a limit current region. The deterioration judging part judges the degree of deterioration of the catalyst based on the output current of the air-fuel ratio sensor when the applied voltage is set to the second voltage.

The present invention relates to an exhaust gas sensor arrangement structure comprising: an exhaust pipe 6 extending from an engine 3 to form a part of an exhaust flow path; an exhaust valve 7 that adjusts an aperture of the exhaust flow path; and a first exhaust gas sensor 8a that detects a predetermined component in an exhaust gas flowing through the exhaust flow path. The first exhaust gas sensor has a detector 80 arranged to protrude into the exhaust flow path. The exhaust valve includes a plate-like valve body 70 that expands and reduces a flow path cross section of the exhaust flow path, and a rotating shaft 71 extending in a direction intersecting with an axial direction of the exhaust flow path and serving as a rotation center of the valve body. A downstream end of the valve body approaches the detector as the valve body is rotated in a direction of reducing the flow path cross section.

A catalyst deterioration diagnosis device, including: a processor to execute, when a cycle of reversal between increasing and decreasing of a fuel amount is disturbed such that the increasing/decreasing of the fuel amount is reversed three or more times in a period that is identical in length with a period in which the increasing/decreasing of the fuel amount is reversed twice when the reversal between increasing and decreasing of the fuel amount is normal, a process of diagnosing the deterioration state of a catalyst based on plural sets of data of the output signal of a downstream oxygen concentration sensor obtained in each unit period during a diagnosis period. The sets of data obtained in each unit period during the diagnosis period is not susceptible to an influence of variations including both increase and decrease of the output signal of the downstream oxygen concentration sensor.

The present invention provides a deterioration diagnosis apparatus for an exhaust gas purification apparatus, including a first sensor that measures the oxygen concentration of the exhaust gas flowing into the exhaust gas purification apparatus, a second sensor that measures the oxygen concentration of the exhaust gas flowing out of the exhaust gas purification apparatus, and diagnosing means for diagnosing deterioration of the exhaust gas purification apparatus on the basis of a difference that appears between a measurement value of the first sensor and a measurement value of the second sensor when the air-fuel ratio of the exhaust gas flowing into the exhaust pas purification apparatus is switched from a lean air-fuel ratio to a rich air-fuel ratio, wherein, when the air-fuel ratio of the exhaust gas is switched from a lean air-fuel ratio to a rich air-fuel ratio, a water-gas shift reaction is generated upstream of the first sensor.