A method and system for monitoring an exhaust gas sensor coupled in an engine exhaust is provided. In one example, the method adjusts an estimate of an exhaust gas oxygen sensor delay time based on a fuel injection ramping time. The fuel injection ramping time compensates for fuel that is injected to the engine while the engine enters or exits a fuel cut-off mode.

A heating system includes at least one electric heater disposed within a fluid flow system and a control device that is configured to determine a temperature of the at least one electric heater based on a model, at least one fluid flow system input, and at least one heater input. The at least one heater input includes at least one physical characteristic of the heating system, the at least one physical characteristic includes at least one of a resistance wire diameter, a heater insulation thickness, a heater sheath thickness, a conductivity, a specific heat and density of the material of the heater, an emissivity of the heater and the fluid flow pathway, and combinations thereof. The control device is configured to provide power to the at least one electric heater based on the temperature of the at least one electric heater.

Systems and methods for diagnosing an exhaust aftertreatment system are provided. A controller determines, for each sensor of a plurality of sensors, one or more performance parameters based on measurement data obtained from the sensor that is indicative of a performance of the sensor or a component of the exhaust aftertreatment system. The controller determines, for each performance parameter, a corresponding degradation level indicator indicative of a performance degradation of the corresponding sensor or the corresponding component of the exhaust aftertreatment system. The controller can determine, for each degradation level indicator, a corresponding diagnosis threshold value for detecting an operational state of the corresponding sensor or the corresponding component of the exhaust aftertreatment system. The controller can determine a multipoint diagnosis threshold value based on the diagnosis threshold values, and determine an operational state of the aftertreatment system using the multipoint diagnosis threshold value.

An engine control system according to the present disclosure includes an oil temperature sensor and a waste gate valve control unit. The oil temperature sensor detects a temperature of an engine oil. The waste gate valve control unit controls opening and closing of a waste gate valve based on the temperature of the engine oil detected by the oil temperature sensor. More specifically, when the temperature of the engine oil detected by the oil temperature sensor is equal to or less than a predetermined threshold, the waste gate valve control unit controls the waste gate valve so that it opens.

Provided is a diagnosis device for an internal combustion engine where the internal combustion engine includes a blow-by gas passage through which blow-by gas flows and the diagnosis device includes a temperature sensor which detects a temperature inside the blow-by gas passage and an abnormality detection unit which detects an abnormality in the internal combustion engine based on a detected value of the temperature sensor.

New and/or alternative approaches to determine mass flow using a flow measurement device in a pulsatile flow context. The flow measurement device is configured to generate a delta-pressure measurement. A semi-physical valve model is generated for the flow measurement device, and the delta-pressure measurement is then is isolated using the model. A discharge coefficient map is determined for the flow measurement device by testing using sets of operating parameters for a system. The operating parameters of the system are then used to determine the discharge coefficient for use in estimating mass flow with the semi-physical valve model. The resultant estimated mass flow can be used to control the system, and a Factor of Effective Area estimate generated using the valve model can be used to determine the status of the flow measurement device and identify or predict a need for maintenance.

Methods and systems for monitoring a NOx sensor for a NOx offset value are described. In one example, the NOx offset value may be based on a minimum NOx concentration observed over an entire drive of a vehicle. The NOx offset monitor may be inhibited in response to inferring or detecting a presence of NH.sub.3 in an exhaust system.

Methods and systems for calculating a plurality of aging factors in a system operating an engine. The calculated aging factors may include one or more of fuel injector drift, exhaust gas recirculation valve obstruction, and mass air flow sensor bias. Mass flow throughout the system, and pressures and temperatures within the system, are observed in an approach that relies on mass preservation concepts to estimate drift, obstruction and bias estimates.

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.

A method for monitoring a pressure sensor in a direct injection system including at least one common rail, a high-pressure fuel pump, a hydraulic circuit connecting the high-pressure pump to the common rail, a passive pressure-limiting valve connected to the hydraulic circuit, configured to open once the pressure in the hydraulic circuit is greater than a threshold pressure, so as to discharge the fuel, including the steps of detecting the opening of the pressure-limiting valve, measuring the pressure P.sub.MES corresponding to the time of opening of the pressure-limiting valve and comparing the measured pressure P.sub.MES to the threshold pressure P.sub.1 in order to detect a drift in the pressure sensor.