An abnormality diagnosis apparatus is an abnormality diagnosis apparatus for a pressure sensor provided in a purge passage that provides communication between an intake passage of an internal combustion engine and a canister, the pressure sensor being closer to the intake passage than a purge valve and a check valve are, the purge valve opening and closing the purge passage, the abnormality diagnosis apparatus for the pressure sensor including: a first determination unit that determines whether the purge valve is being kept in a closing state and a fuel cut in which fuel injection in the internal combustion engine is stopped is being executed; and a second determination unit that determines whether the pressure sensor is abnormal, based on a detection value of the pressure sensor, when the positive determination is made by the first determination unit.

A sensor output value estimation device that effectively estimates sensor output values reflecting a response delay of a temperature sensor. The device includes an estimated gas temperature calculation unit for calculating an estimated gas temperature of an engine on a basis of at least a running condition of the engine and a state quantity of the gas in the engine. The device also includes an estimated sensor output value calculation unit for calculating an estimated sensor output value reflecting the response delay of the temperature sensor on a basis of the calculated estimated gas temperature and a pre-stored first model formula specifying a relation among the temperature change time constant of the temperature sensor, the gas flow rate, and the gas temperature.

A method and a device for monitoring gas sensors in an internal combustion engine, in which in a steady-state operation of the internal combustion engine, the output signal of the gas sensor is filtered by a high-pass filter and higher-frequency signal components are analyzed by a comparison with an appropriately processed model value. When using the method and the device for executing the method, electrically oscillating gas sensors or the incoupling of interference variables or faults in the evaluation circuit, especially in the case of exhaust gas sensors in an exhaust-gas purification and reducing system, are able to be detected, which minimizes faulty interpretations in a dynamic diagnosis. This monitoring function is advantageously combinable with dynamic diagnosis functions that likewise analyze higher-frequency signal components by a comparison with appropriately processed model values. This increases the operational reliability of the exhaust-gas purification or reducing system.

A method for operating a drive system including a drive engine for a motor vehicle, including carrying out an acceleration monitoring of the motor vehicle; switching to an alternative monitoring when a signal, which is relevant for the acceleration monitoring and for which a substitute signal exists, does not exist or has failed, and when a driver input which is below a predefined threshold value is specified, and/or a braking intent is specified.

Methods and systems are provided for conducting a fuel tank pressure transducer rationality test diagnostic procedure in vehicles with sealed fuel tanks. In one example, vehicle-to-vehicle (V2V) or vehicle-to-infrastructure-to-vehicle (V2I2V) technology may be utilized to obtain fuel tank pressure transducer data from a select crowd of vehicles, where the select crowd may be based on the vehicles in the select crowd experiencing similar ambient temperature and weather as the vehicle being diagnosed. In this way, FTPT data from vehicles in the select crowd may be compared to FTPT data in the vehicle being diagnosed, in order to indicate whether the FTPT in the vehicle being diagnosed is functioning as desired, where such a diagnostic can be performed without unsealing the fuel tank on either the vehicle being diagnosed or the vehicles in the select crowd, and which may thus reduce undesired evaporative emissions.

An exhaust gas control apparatus includes a first catalyst, a filter, and an electronic control unit. The electronic control unit is configured to alternately execute lean control and rich control multiple times. The lean control is control for, over a period longer than a period from when a target air-fuel ratio is set to a predetermined lean air-fuel ratio until an air-fuel ratio of exhaust gas flowing out from the first catalyst becomes greater than the stoichiometric air-fuel ratio, setting the target air-fuel ratio to the predetermined lean air-fuel ratio. The rich control is control for, over a period longer than a period from when the target air-fuel ratio is set to a predetermined rich air-fuel ratio until the air-fuel ratio of exhaust gas flowing out from the first catalyst becomes smaller than the stoichiometric air-fuel ratio, setting the target air-fuel ratio to the predetermined rich air-fuel ratio.

An engine airflow management system includes an inlet portion to receive ambient air and a mass airflow (MAF) sensor to sense mass flow rate of air passed through the inlet portion. The airflow management system includes a throttle body to selectively restrict airflow and a throttle position sensor (TPS) to sense an opening value of the throttle body. The airflow management system includes an intake manifold in fluid connection with the throttle body configured to direct airflow to a number of combustion cylinders. A manifold air pressure (MAP) sensor detects air pressure at the intake manifold. A controller is programmed to monitor signals from each of the MAF sensor, TPS, and the MAP sensor and generate a residual error value based on a difference between a model-based value and a corresponding monitored signal. A response action is based on a trend of at least two residual error values.

Methods and systems are provided for performing rationality check of a hydrocarbon sensor in an evaporative emission control system. In one example, a method may include sensing fuel vapors vented from a fuel vapor canister to atmosphere via the sensor, and performing sensor rationality check by flowing fuel vapors from a fuel tank to the fuel vapor canister via the sensor during loading of the fuel vapor canister.

An engine system includes an engine, an atmospheric pressure sensor, an intake pressure sensor, and an electronic control unit. The electronic control unit is configured to execute atmospheric pressure learning for learning a relation between atmospheric pressure and an intake air amount of the engine based on the atmospheric pressure detected by the atmospheric pressure sensor, and execute fuel injection control of the engine using an initial value of an intake air amount model obtained based on the atmospheric pressure learning. The electronic control unit is configured to execute the fuel injection control of the engine using an initial value of the intake air amount model obtained based on the intake pressure detected by the intake pressure sensor, when rotational speed of the engine is less than a specified rotational speed at start of the fuel injection control of the engine.

Methods and systems are provided for detecting exhaust gas oxygen sensor degradation due to sealant off-gassing. In one example, a method may include indicating exhaust gas oxygen sensor degradation due to sealant off-gassing responsive to a change in fueling demand without a change in driver-demanded torque after a threshold exhaust temperature has been reached. In response to the indication, a measurement correction may be learned and applied to measurements of the exhaust gas oxygen sensor in order to accurately determine an air-fuel ratio of the exhaust.