A preheating control for controlling an energization of a heater is executed so that a sensor element of an exhaust gas sensor is preheated within a temperature range in which no element crack caused by water occurs until a predetermined preheating period elapses after an engine starts. In performing the preheating control, first, an energization duty of the heater is set to a preheating promotion energization duty to promptly raise a temperature of the sensor element until it is determined that the temperature of the sensor element reaches a predetermined upper limit temperature. After it is determined that the temperature of the sensor element reaches the upper limit temperature, the energization duty of the heater is set so that the temperature of the sensor element is maintained at the upper limit temperature to sufficiently raise the temperature of the overall sensor element during the preheating control.

Methods and systems are provided for accurately inferring an exhaust temperature during steady-state and transient vehicle operation based on the duty cycle of an exhaust gas sensor heating element. A steady-state temperature is inferred based on an inverse of the duty cycle, and then adjusted with a transfer function that compensates for transients resulting from changes in vehicle speed, and load, and for the occurrence of tip-in and tip-out events. The inferred temperature can also be compared to a modeled temperature to identify exhaust temperature overheating conditions, so that mitigating actions can be promptly performed.

Methods and systems for evaluating whether or not a fuel amount that is greater than a threshold has been release to an engine via fuel injectors when the fuel injectors are commanded off are presented. In one example, an oxygen sensor is activated and engine cranking is prevented until a pumping current of the oxygen sensor is proportionate to a concentration of oxygen sensed via the oxygen sensor so that released fuel may be observed during engine starting.

Disclosed is a particulate matter sensor having a structure which may achieve a reduction in distance between two electrodes and an increase in area of measurement electrodes so as to facilitate enhancement in measurement accuracy, reliability, and sensitivity, and reduce influence on sensitivity according to sensor mounting directions. The particulate matter sensor may include a housing provided with an inlet and an outlet, and a sensing unit installed within the housing so as to pass exhaust gas, the sensing unit may include a laminate including an electrically insulating substrate, a first electrode provided on one surface of the electrically insulating substrate, a second electrode provided on the other surface of the electrically insulating substrate, and a porous layer stacked on one of the first electrode and the second electrode and having a structure to pass the exhaust gas, and the laminate is spirally wound on a base unit.

Methods and systems are provided for a particulate matter sensor. In one example, the sensor may include a concave inlet for admitting exhaust gas from an exhaust passage downstream of a particulate filter into the sensor.

Provided are a novel exhaust pipe temperature estimation device and a sensor heater control apparatus for an exhaust gas sensor using the same that accurately estimates an estimation exhaust pipe temperature when an internal combustion engine is stopped and restarted in response to a change of an environmental condition of the internal combustion engine and controls an operation of a sensor heater based on the estimated estimation exhaust pipe temperature. Thus, at least first correction information Tz based on a change of an exhaust pipe temperature and an elapsed time at stop, second correction information Ty based on a change of an internal combustion engine temperature at the stop of the internal combustion engine, and third correction information Tz based on a change of a cooling degree due to outdoor air during stop from the stop to restart are obtained, an estimation exhaust pipe temperature at the stop is corrected using at least one or more pieces of the correction information at restart of the internal combustion engine to estimate an estimation exhaust pipe temperature at the restart, and an estimation exhaust pipe temperature during an operation of the internal combustion engine thereafter is obtained using the estimation exhaust pipe temperature as an initial value, and further, a heating operation of a sensor heater is started when the estimation exhaust pipe temperature becomes equal to or higher than a predetermined value.

A control apparatus mounted on a diesel vehicle including an oxidation catalyst, a selective reduction catalyst, and a gas sensor includes an activation determination section, a concentration computation section, and a deterioration determination section. The concentration computation section computes the concentration of flammable gas from a sensor output in a period during which the activation determination section determines that the oxidation catalyst is not in the activated state and computes the concentration of ammonia gas from the sensor output in a period during which the activation determination section determines that the oxidation catalyst is in the activated state. The deterioration determination section determines whether or not the oxidation catalyst has deteriorated, on the basis of the concentration of the flammable gas computed by the concentration computation section.

A control system includes an electric heater disposed within an exhaust fluid flow pathway, and a control device for receiving at least one input selected from the group consisting of temperature readings along the exhaust fluid flow pathway, alternator power/current/voltage, battery power/current/voltage/state of charge, IAT and EAT profiles, mass flow rate of an exhaust fluid flow, NH.sub.3 slip, TCR characteristics of the heater, alternator speed, engine speed, state of aging of an aftertreatment component, state of aging of engine, aging degradation characteristics, a dosing rate and a temperature of DEF, NH.sub.3 storage condition of aftertreatment system, an ambient temperature, and combinations thereof. The control device modulates power to the heater based on the at least one input such that the heater provides different power output as a function of the at least one input and a continuously variable power output during operation of the exhaust system.

Methods and systems are provided for an oxygen sensor heater. In one example, a method may include applying a less than maximum duty cycle of voltage to the oxygen sensor heater during an engine cold start (e.g., when a temperature of the oxygen sensor is less than its light-off temperature) and adjusting the applied duty cycle of voltage to maintain a constant amount of power. In this way, the oxygen sensor may be heated at a constant rate even as a resistance of the oxygen sensor heater increases, decreasing an amount of time before the oxygen sensor reaches its light-off temperature.

The control system of an internal combustion engine controls an internal combustion engine comprising an exhaust sensor. The control system comprises a motoring device driving rotation of a crankshaft of the internal combustion engine, a motoring control part configured to control the motoring device, a heater control part configured to control supply of electric power to the heater, and a temperature estimating part configured to estimate a temperature of the sensor element. The motoring control part is configured to drive the motoring device for a predetermined time when the temperature of the sensor element estimated by the temperature estimating part is outside a predetermined cracked element temperature region while the heater control part is supplying electric power to the heater, and stop driving the motoring device when the temperature of the sensor element is within the cracked element temperature region.