An internal combustion engine-based system includes an internal combustion engine. The internal combustion engine-based system includes an engine interrupt connected to the engine. The engine interrupt is configured to selectively stop the operation of the engine. The internal combustion engine-based system includes a controller in communication with the engine interrupt. The internal combustion engine-based system includes a carbon monoxide detector in communication with the controller. The controller uses the engine interrupt to stop the operation of the engine when the carbon monoxide detector provides the controller with signals that are representative of a carbon monoxide level proximate the internal combustion engine that together form a trend of building carbon monoxide amounts over a set time interval.

Controlling a marine engine includes operating the engine according to an initial set of mapped parameter values to achieve a first target fuel-air equivalence ratio, determining a first actual fuel-air equivalence ratio, and using a feedback controller to minimize a difference between the first target and actual ratios. Feedback controller outputs are used to populate an initial set of adapt values to adjust combustion parameter values from the initial set of mapped parameter values. The method includes transitioning to operating the engine according to a subsequent set of mapped parameter values to achieve a different target fuel-air equivalence ratio. The method includes determining a second actual fuel-air equivalence ratio, using the feedback controller to minimize a difference between the second target and actual ratios, and using feedback controller outputs to populate a subsequent set of adapt values to adjust combustion parameter values from the subsequent set of mapped parameter values.

A system for diagnosing a sensor of an exhaust aftertreatment system may include receiving a first tank level value from a sensor. A plurality of reductant dosing command values over a period of time are received. A dosed reductant value is determined responsive to the plurality of reductant dosing command values reaching a threshold integrated value. A second tank level value is received from the sensor responsive to the dosed reductant value reaching the threshold integrated value. A sensor-estimated dosing value is determined based on the difference between the first tank level value and the second tank level value. The sensor may be diagnosed as performing outside of an acceptable calibration range based on the difference between the sensor-estimated dosing value and the dosed reductant value.

A vehicle includes an engine air intake having a humidity sensor, and a system having a nozzle positioned in the air intake and fluidly connected to a reservoir. The vehicle has a controller configured to activate the system to deliver fluid from the nozzle into the intake while the engine is inoperative and generate a diagnostic code in response to a change in humidity measured by the sensor being less than a threshold value. A method of controlling a vehicle includes measuring a baseline humidity (H1) using a humidity sensor in an air intake of an engine, and controlling a misting system to mist fluid from a reservoir into the air intake and adjacent to the humidity sensor while the engine is inoperative. The method measures a post-fluid delivery humidity (H2) using the humidity sensor, and generates a diagnostic code based on a comparison of H1 and H2.

An ECM determines a failure exist and a failure site in a control valve device from first and second failure diagnoses. In the first failure diagnosis, a failure is determined to have occurred if an opening amount that represents an absolute value of a difference between a detected opening amount and a target opening amount of a valve body is greater than a preset threshold when the target opening amount of the valve body is constant for a predetermined time. In the second failure diagnosis, a failure is determined to have occurred if an opening amount that represents the absolute value of the difference between the opening amount of the valve body when fully open or fully closed and the detected opening amount is greater than the preset threshold when a portion rotating integrally with the valve body has been pressed against a stopper continuously for a predetermined time.

The abnormality diagnosis system 1, 1, 1 of an ammonia detection device 46, 71 comprises: an air-fuel ratio detection device 41, 72 arranged in the exhaust passage 22 at the downstream side of the catalyst 20; an air-fuel ratio control part 51 configured to control an air-fuel ratio of exhaust gas; and an abnormality judgment part 52 configured to judge abnormality of the ammonia detection device. The air-fuel ratio control part performs rich control making the air-fuel ratio of the inflowing exhaust gas richer than a stoichiometric air-fuel ratio. The abnormality judgment part judges that the ammonia detection device is abnormal if, after start of the rich control, an output value of the ammonia detection device does not rise to a reference value before the air-fuel ratio detected by the air-fuel ratio detection device falls to a rich judged air-fuel ratio richer than a stoichiometric air-fuel ratio.

On-board diagnostic monitoring of a two-stroke cycle, opposed-piston engine includes diagnostic monitoring of an air handling system equipped with a supercharger to determine whether the supercharger is functioning properly.

A method provides a diagnostic on a combined humidity and temperature sensing device including a humidity sensor having a humidity sensing element, a temperature sensor, and a heater. The method comprises obtaining a first temperature and a first relative humidity, heating the humidity sensing element with the heater, obtaining a second temperature and a second relative humidity after heating the humidity sensing element, and determining a difference between the first temperature and the second temperature and a difference between the first relative humidity and the second relative humidity. Diagnostic information representative of a possible malfunction of the humidity sensor is output when the difference between the first temperature and the second temperature is higher than a predetermined temperature difference threshold and the difference between the first relative humidity and the second relative humidity is lower than a predetermined humidity difference threshold.

A sensor failure diagnostic apparatus includes a first estimation unit to estimate a mixing ratio of each type of a molecular structure included in a fuel, based on combustion parameters when a combustion of an internal combustion engine is executed in different combustion conditions, among the combustion parameters sensed by a combustion sensor, a second estimation unit to estimate the mixing ratio, based on characteristic parameters sensed by a characteristic sensor, a combustion sensor diagnostic unit to determine whether a failure of the combustion sensor exists, based on a sensed value of the combustion sensor when the combustion is not executed, and a characteristic sensor diagnostic unit to determine whether a failure of the characteristic sensor exists, by comparing the mixing ratio estimated by the first estimation unit with the mixing ratio estimated by the second estimation unit when the combustion sensor diagnostic unit determines the combustion sensor is normal.

A NOx sensor abnormality detector for a NOx sensor includes a measurement chamber, a pump cell, and a sensor cell. The NOx sensor abnormality detector includes a signal receiving section configured to receive the detection value of the sensor cell, a reduction process executing section configured to execute a reduction process that reduces the discharge function of the pump cell, and an abnormality determining section configured to perform abnormality determination of the NOx sensor. The NOx sensor abnormality detector is configured to execute abnormality detection control in which the abnormality determining section performs abnormality determination of the NOx sensor based on the detection value of the sensor cell, which is input to the signal receiving section, after the reduction process executing section starts the reduction process.