A controller is applied to an internal combustion engine in which an electrically heated catalyst that is heated when supplied with electric power is installed in an exhaust passage. The controller is configured to perform a preheating process of warming up a first exhaust catalyst by supplying electric power to the electrically heated catalyst through control over a power supply before a start of the internal combustion engine. The controller is configured to, when an insulation resistance of the electrically heated catalyst at a start of the preheating process is lower than a threshold, perform the preheating process while decreasing a voltage supplied to the electrically heated catalyst.

A heating system includes at least one electric heater disposed within the fluid flow system. A control device includes a microprocessor and is configured to determine a temperature of the at least one electric heater based on a model and at least one input from the fluid flow system. 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.

An electrically heated catalyst device has a catalyst that purifies exhaust gas from an engine, and is configured to heat the catalyst with electric power that is supplied from an electric storage device. A current sensor detects a current that is supplied to the electrically heated catalyst device. A current sensor detects an input/output current of the electric storage device. A controller executes failure determination control to determine whether the current sensor has a failure. In the failure determination control, the controller estimates a current that is supplied to the electrically heated catalyst device using a detection value of the current sensor and compares the estimated current with a detection value of the current sensor to determine whether the current sensor has a failure.

A control device executes abnormality detection processing for detecting an abnormality of a current sensor. The abnormality detection processing includes first processing which is executed in a case where, during reception of electric power from a power supply, a state of charge of a power storage device is equal to or greater than a predetermined amount and electric power is supplied to an electrically heated catalyst device. The first processing includes processing for detecting an abnormality of the current sensor by estimating a current supplied to the electrically heated catalyst device using a detection value of a charging current sensor and comparing the estimated value with a detection value of the current sensor.

An injection assembly for a vehicle exhaust system includes a housing defining a fluid cavity, a doser mounted to the housing and configured to inject a fluid into the fluid cavity, and a valve to control flow of the fluid. The valve is moveable between an open position and a closed position. A resilient member is configured with a biasing force to bias the valve to the closed position. The biasing force is overcome when fluid is heated downstream of the valve and exceeds a predetermined pressure level to allow backflow into the fluid cavity.

A heater is provided that includes at least one resistive heating element having a material with a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile. The heater can include a plurality of circuits disposed in a fluid path to heat fluid flow.

A system includes a first heater positioned in or proximate to an exhaust aftertreatment system in exhaust gas-receiving communication with an engine, a second heater positioned downstream of the first heater, and a controller coupled to the first and second heaters. The controller is structured to determine, based on information indicative of a temperature regarding the exhaust aftertreatment system, that the temperature is below a temperature threshold; receive information regarding a characteristic of a battery coupled to the first heater and the second heater; control the temperature regarding the exhaust aftertreatment system without using the first or second heaters in response to determining that the characteristic of the battery is below a first threshold; and control a temperature regarding the exhaust aftertreatment system using the first heater in response to determining that the characteristic of the battery is above the first threshold but below a second threshold.

Methods and systems are provided for a NO.sub.x sensor. In one example, a method includes heating a NO.sub.x sensor during a vehicle off in response to a cumulative heat energy applied to the NO.sub.x.

A system includes an aftertreatment system having a catalyst, a heater, at least one sensor configured to determine an exhaust gas temperature, and a controller. The controller is structured to determine whether the exhaust gas temperature is at or below a predefined threshold temperature, provide a first command to start and control the heater in response to the exhaust gas temperature being at or below the predefined threshold temperature, modulate control of the heater as a function of the predefined threshold temperature and an actual temperature, and selectively provide a second command for a close post injection based on the exhaust gas temperature. The controller is further structured to coordinate the first and second commands using a chaining sequence, wherein the first command is provided followed by the second command only if the predefined threshold temperature is not attained by the first command.

A method for operating a heater system including a resistive heating element having a material with a non-monotonic resistivity vs. temperature profile is provided. The method includes heating the resistive heating element to within a limited temperature range in which the resistive heating element exhibits a negative dR/dT characteristic, operating the resistive heating element within an operating temperature range that at least partially overlaps the limited temperature range, and determining a temperature of the resistive heating element such that the resistive heating element functions as both a heater and a temperature sensor. The resistive heating element can function as a temperature sensor in a temperature range between about 500° C. and about 800° C., and the non-monotonic resistivity vs. temperature profile for the material of the resistive heating element can have a local maximum and a local minimum.