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.

An apparatus includes circuitry configured to calculate a temperature of exhaust flowing into an exhaust after-treatment system as a first exhaust temperature, calculate a temperature of exhaust flowing out from the exhaust after-treatment system as a second exhaust temperature, calculate a rate of change over time of the first exhaust temperature and a rate of change over time of the second exhaust temperature, and judge if the exhaust after-treatment system is in a removed state removed from the exhaust passage based on a difference between the rate of change over time of the first exhaust temperature and the rate of change over time of the second exhaust temperature.

A control device comprises a catalyst warmup control part configured to supply electric power to a conductive base to warm up a catalyst device. The catalyst warmup control part is provided with a first estimating part configured to estimate a temperature of the conductive base based on an engine operating state, a second estimating part configured to estimate a temperature of the conductive base based on a resistance value of the conductive base detected when supplying current to the conductive base, and an electric power control part configured to control an amount of electric power supplied to the conductive base when warming up the catalyst device based on a result of comparison of magnitudes of a first estimated temperature of the conductive base estimated by the first estimating part and a second estimated temperature of the conductive base estimated by the second estimating part.

An exhaust gas treatment system, comprising an ozone purification system. The ozone purification system comprises an ozone amount control apparatus (209), used to control an amount of ozone so as to effectively oxidize gas components to be treated in exhaust gas, the ozone amount control apparatus (209) comprising a control unit (2091). By means of the present exhaust gas treatment system, particulate matter can be effectively removed from exhaust gas, and the system features a better exhaust gas purification treatment effect.

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 of controlling an exhaust system for a diesel engine comprises providing an aftertreatment system comprising a first catalyst and a diesel exhaust fluid injection system, determining a preliminary dose of a diesel exhaust fluid of the diesel exhaust fluid injection system based on an incoming exhaust gas flow and an exhaust gas temperature, determining an NH.sub.3 factor based on incoming exhaust gas oxygen concentration and the incoming exhaust gas flow temperature, and determining a final dose of diesel exhaust fluid by multiplying the preliminary dose of diesel exhaust fluid by the NH.sub.3 factor.

A device that includes a conduit, a first window, a second window, a first catalyzed layer, a second catalyzed layer, an optical source, and an optical detector is disclosed. The conduit may be configured to receive an exhaust gas. The first catalyzed layer may be disposed on the first window and the second catalyzed layer may be disposed on the second window. The first catalyzed layer and the second catalyzed layer may be configured to cause a reaction with soot in the exhaust gas at an activation temperature to reduce accumulation of the soot on the first window and the second window. The optical source may be configured to emit a beam of light into the conduit through the first window. The optical detector may be configured to receive at least a portion of the beam of light through the second window.

Various embodiments include a method of ascertaining the oxygen load of a catalytic converter disposed in an exhaust tract of an internal combustion engine with an exhaust gas sensor is disposed downstream of the catalytic converter comprising: generating a signal using the exhaust gas sensor indicating a proportion of nitrogen oxide and/or ammonia in the exhaust gas; and ascertaining the oxygen load of the catalytic converter at least partly on the basis of the signal from the exhaust gas sensor.

A diagnostic system (10) is provided and includes a sensor (24) disposed downstream from an exhaust gas aftertreatment system. Also included in the diagnostic system (10) is a central diagnostic unit (35) configured to diagnose a condensation condition associated with the sensor (24) for mitigating a sensor failure due to water condensation on the sensor (24), the central diagnostic unit (35) performing the diagnosis on the condensation condition based on water storage and release information related to a component of the exhaust gas aftertreatment system. The sensor (24) is activated based on the water storage and release information.

A method and an apparatus including a processing circuit structured to: receive a first signal indicative of an upstream air-fuel equivalence ratio from a first sensor positioned upstream of an intake of a catalyst, the first signal defining a duty cycle, receive a second signal indicative of a downstream air-fuel equivalence ratio from a second sensor positioned downstream of the intake of the catalyst, adjust the duty cycle based at least in part on the second signal, and provide a fault signal in response to the duty cycle not meeting a duty cycle range for a predetermined period of time. A notification circuit is structured to provide a notification indicating that the second sensor is faulty in response to receiving the fault signal.