An exhaust sensor 1 comprises a sensor cell 51, a voltage application circuit 61, a current detection circuit 62 and a concentration calculating part 80a. The current detection circuit detects a first current flowing through the sensor cell when fuel cut control is being performed in the internal combustion engine and a predetermined voltage is applied from the voltage application circuit to the sensor cell, and detect a second current flowing through the sensor cell when normal control is being performed in the internal combustion engine and the predetermined voltage is applied from the voltage application circuit to the sensor cell. The concentration calculating part is configured to calculate the concentration higher with respect to the second current when the first current is relatively low compared with when the first current is relatively high.

Methods and systems are provided for reducing blackening of an oxygen sensor due to voltage excursions into an over-potential region. Before transitioning the sensor from a lower voltage to an upper voltage during variable voltage operation, an operating temperature of the sensor is reduced via adjustments to a sensor heater setting. The reduction in temperature increases the range of temperatures available to the sensor before the over-potential region is entered.

A sensor for detecting electrically conductive and/or polarizable particles, in particular for detecting soot particles, includes a substrate and at least two electrode layers, a first electrode layer and at least one second electrode layer. Which is arranged between the substrate and the first electrode layer. At least one insulation layer is formed between the first electrode layer and the at least one second electrode layer and at least one opening is formed in both the first electrode layer and the at least one insulation layer. At least some sections of the opening in the first electrode layer and of the opening in the insulation layer are arranged one above the other, such that at least one passage is formed to the second electrode layer.

Methods and systems are provided for adjusting heater power of an oxygen sensor. In one example, a method for an engine includes adjusting heater power of a heating element of the oxygen sensor when the heater power increases by a threshold amount. The method includes subsequently increasing heater power back to a baseline power level responsive to a temperature of the heating element.

A system for sensing and controlling a fuel gas composition may include a plurality of micro-sensors mounted in a single chamber, with each of the micro-sensors being configured to sense a characteristic of a mixture of gaseous fuel introduced into the chamber. The system may also include a plurality of heating elements, with each of the heating elements being associated with one of the plurality of micro-sensors, and the plurality of heating elements being configured to implement a different temperature level at each of the micro-sensors. The system may also include a microprocessor configured to determine a thermodynamic property of the mixture of gaseous fuel at the different temperature levels at each of the micro-sensors as a function of the characteristic sensed by each micro-sensor, correlate the thermodynamic property to a fuel gas composition of the mixture of gaseous fuel, and control an amount of at least one constituent in the mixture of gaseous fuel as a function of the fuel gas composition determined by the correlation.

A removing poison apparatus of a lambda sensor includes: a lambda sensor detecting an oxygen concentration included in an exhaust gas; and a control unit differentiating a heating temperature and a heating time to remove poison of the lambda sensor depending on a lambda signal output from the lambda sensor in an overrun condition of the engine. By heating the lambda sensor depending on the magnitude of the lambda signal output from the lambda sensor, the lambda sensor may be inhibited from being degraded by combusting the material poisoned to the electrode of the lambda sensor and the failure of the lambda sensor may be correctly determined.

A control device for an exhaust gas sensor includes first means for estimating a temperature of a sensor element in accordance with impedance of a solid electrolyte, and second means for estimating the temperature of the sensor element in accordance with resistance of a heater. A first element temperature according to impedance of the sensor element in a predetermined detection timing is detected by the first means, and a second element temperature according to resistance of a heater of the sensor element in the predetermined detection timing is detected by the second means. The control device corrects the temperature of the sensor element that is estimated in accordance with heater resistance by the second means in accordance with a difference between the first element temperature and the second element temperature.

A desired effective voltage can be ensured with certainty in a preheating control. An operation control part 52 reads a correction value c with respect to a battery voltage Vb at the time of performing correction based on preliminarily stored correlation between a battery voltage Vb of a vehicle-use battery and a correction value c (S104, S106), and compensates for lowering of an effective value of a pulse voltage by adding a correction value c to a duty ratio calculated by a predetermined arithmetic expression thus ensuring a desired effective voltage with certainty in a preheating control.

Methods and systems are provided for indicating water at an oxygen sensor based on power consumption of a heating element of the oxygen sensor. In one example, water may be indicated at an oxygen sensor positioned in an intake of an engine responsive to power consumption of the heating element of the oxygen sensor increasing above a baseline level. Engine operating parameters may then be adjusted based on the water indication and the power consumption.

A method for determining soot in exhaust gases of burners or internal combustion engines with the aid of a sensor element which includes at least two measuring electrodes exposed to the exhaust gas and one heating element, a voltage being applied to the at least two measuring electrodes during a measuring phase and the current flow or electrical resistance occurring between the measuring electrodes being determined and output as a measure for the particle concentration or the particle mass flow, characterized in that during the measuring phase, the temperature of the sensor element is monitored and the sensor element is heated by the heating element, if the temperature of the sensor element falls below a limiting temperature.