Abstract: An air/fuel-ratio detecting apparatus includes a compact layer arranged on the outer surface of a solid electrolyte layer to externally conceal a gas diffusion layer, solid electrolyte layer, outer measuring electrode, and reference electrode to restrain entry of exhaust gas. A gas introduction window is formed in the compact layer to have a predetermined width. The gas introduction window allows entry of exhaust gas toward the gas diffusion layer and the outer measuring electrode in the range of an opening width of the gas introduction window.

Abstract: A failure diagnostic apparatus for an air-fuel ratio detecting device has an exhaust emission purifying device provided in an exhaust passage; an air-fuel ratio detecting unit for detecting the air-fuel ratio of an exhaust gas from the purifying device; a first determination unit for determining that the air-fuel ratio is estimated to be rich for longer than a first predetermined period of time; a second determination unit for determining that the air-fuel ratio is estimated to be lean for longer than a second predetermined period of time; and a failure diagnosis device for determining that the air-fuel ratio detecting device has failed if a variation in the air-fuel ratio, calculated based on the detected air-fuel ratios until both the first and second determination units make the determinations, is equal to or less than a predetermined value.

Abstract: The device comprises a voltage divider (Rv1, Rv2) to whose two terminals the oscillator signal with a phase position that is mutually opposed is supplied until, in the instance of a switched-on probe heating, the voltage (VRpvs) that is proportional to the probe internal resistance (Rpvs) falls below a predetermined set value (set), whereby, at this point in time, the output signal of the oscillator (SZ) is supplied to both terminals of the voltage divider (Rv1, Rv2) with the same phase position (area 1) thus effecting an amplitude change-over (amplitude amplification).

Abstract: An A/F signal proportional to an oxygen concentration in the exhaust gas from an internal combustion engine is output upon application of a voltage based on an instruction from a microcomputer. At the time an element resistance is detected, a bias instruction signal Vr from the microcomputer is converted by a D/A converter 21 to an analog signal Vb. An output voltage Vc obtained by removing high frequency components from the analog signal Vb through an LPF 22 is input to a bias control circuit 40. During this time period in which the element resistance is detected, an accurate A/F signal is not output. Therefore, the A/F signal that has theretofore prevailed is held by a Sample/Hold circuit 70 to thereby prevent the use of an erroneous A/F signal. Namely, at the time of detecting the element resistance, the detected value of the oxygen concentration is prevented from becoming abnormal. As a result, an accurate A/F control can be executed using the detected element resistance.

Abstract: The measuring sensor, particularly a lambda probe, has a ceramic sensor member retained at a high temperature during measuring operation. It is shielded from water droplets, carried along in the gas to be analyzed, by a heated protective housing, permeable for the gas to be analyzed, by which water droplets carried along in the direction of the sensor member are evaporated before reaching the sensor member. In this way, the water droplets are unable to cause any shock-like temperature drops at spots on the surface of the sensor member or material flaking.

Abstract: A highly flexible current detection circuit for an A/F sensor, that can readily provide for a change to an A/F sensor having a difference characteristic. The A/F sensor current detection circuit of the invention comprises: an operational amplifier for generating a voltage to be applied to the A/F sensor; a current-measuring first resistor connected between the operational amplifier and the A/F sensor; voltage-dividing second and third resistors connected in series with each other with one end thereof connected between the operational amplifier and the first resistor; a first output terminal provided between the operational amplifier and the first resistor; a second output terminal provided between the first resistor and the A/F sensor; and a third output terminal provided between the voltage-dividing second and third resistors. When measuring the sensor element admittance with this circuit, the third output terminal is used in place of the first output terminal.

Abstract: A novel abnormality detection device for an air-fuel ratio sensor able to more accurately detect an abnormality, provided with an air-fuel ratio sensor arranged in an exhaust passage of an internal combustion engine for detecting an air-fuel ratio based on a current generated in accordance with a concentration of oxygen in the exhaust gas along with application of voltage and an air-fuel ratio sensor activating means for activating the air-fuel ratio sensor, wherein the activity of the air-fuel ratio sensor is maintained even after the internal combustion engine is stopped and an abnormality of the air-fuel ratio sensor is detected based on an output of the air-fuel ratio sensor upon and/or after the elapse of a first predetermined time after the internal combustion engine is stopped.

Abstract: Process for determining properties of liquid particles of engine exhaust gas, wherein the process includes detecting Raman scattering produced in a test area by excitation with one of a laser, a laser diode, and a diode laser and determining at least one of a type and composition of individual constituents of the liquid particles of the engine exhaust gas and concentrations of individual constituents of the liquid particles of the engine exhaust gas. This abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: A gas sensor includes a sensor element having a specific function, and a housing containing the sensor element therein and including a thread section, and a sealing surface which forms a sealing section together with an installation section at a position deeper than the thread section in a direction in which the sensor element is inserted. When the housing is screwed into the installation section, the release torque of the housing at 850° C. (1123 K) is 9 N·m or more, and an estimated value of a gap formed between the sealing surface and the installation section at 850° C. (1123 K) that is calculated according to a specific equation is 31 &mgr;m or less.

Abstract: A device according to the present invention is provided with element temperature measurement voltage application circuit for temporarily applying a predetermined voltage for element temperature measurement to a sensor element of an air-fuel ratio sensor equipped to an exhaust system of an internal combustion engine, first sensor output reading circuit for reading in a sensor output just before applied with the voltage, and second sensor output reading circuit for reading in a sensor output being applied with the voltage, wherein the element temperature of the air-fuel ratio sensor is estimated based on the sensor output just before applied with the voltage and the sensor output being applied with the voltage. Further, during internal resistance measurement of the sensor element of the air-fuel ratio sensor equipped to the exhaust system of the internal combustion engine, a voltage applied to the heater for heating the sensor element is maintained to be constant.

Abstract: A method for analyzing the exhaust emissions of large industrial engines that: produces emission information in real time and permits the generation of test results immediately after an emission test is conducted, is disclosed. The method includes the real time calculation of exhaust volumetric flow rate from fuel gas flowrate and the use of real time intake manifold conditions to determine engine load from an engine load curve. A portable apparatus for performing the method, comprising a programmed computer, data collection buffer, computer readable database and display device is also disclosed.

Abstract: A fuel injector (5) injects fuel to generate an air-fuel mixture that is burnt in the engine (1), and a sensor (16) detects an air-fuel ratio of the air-fuel mixture from an exhaust gas composition of the engine (1). A controller (11) calculates a dead time representing a lag between the air-fuel ratio variation of the air-fuel mixture and the air-fuel ratio variation detected by the sensor (16), and calculates an estimated state quantity by applying a dead time compensation according to Smith method and a disturbance compensation to the air-fuel ratio detected by the sensor (16). By determining an air-fuel ratio feedback correction amount based on the estimated state quantity applying a sliding mode control process, the response and stability of air-fuel ratio control is improved.

Abstract: A circuit arrangement for coupling with a sensor having two output terminals is disclosed wherein one terminal is coupled to a first ground and the circuit arrangement is coupled with a second ground. The circuit arrangement comprises an attenuator coupled with the output terminals of the sensor, first and second buffers coupled with the attenuator to generate respective output signals, a differential amplifier receiving the output signals of the buffers, and a current source generating a bias current which is fed to the input terminal not coupled with ground.

Abstract: A method and an arrangement for determining the concentration of an oxygen-containing compound in a test gas in an external volume are presented with the external volume containing also additional oxygen. The method utilizes a sensor having a first cavity which is connected to the external volume via a first diffusion barrier and a second cavity which is connected to the first cavity via a further diffusion barrier. In addition, means for reducing the oxygen concentration in the first cavity and means for detecting the concentration of oxygen in the second cavity are provided. The reduction of the oxygen concentration in the first cavity takes place in a first phase to a value at which a change of the concentration of the oxygen-containing compound does not occur. In a second phase, a further reduction takes place in the first chamber to a value at which also a reduction of the concentration of the first oxygen-containing compound occurs.

Abstract: A sensor element for limit current probes for determining the &lgr; value of gas mixtures and a method of calibrating such sensor elements. The sensor element has an internal and an external pump electrode arranged on a ceramic body, the internal pump electrode being arranged in a diffusion channel delimited by a diffusion barrier, and a gas intake orifice running through the ceramic substrate and the diffusion channel in a direction that is essentially perpendicular to the surface of the ceramic substrate. The diffusion resistance of the diffusion barrier can be adjusted essentially linearly by selectively changing the diameter of the gas intake orifice. Calibration is performed by selecting at least one sensor element of a production lot, whose pump voltage is, measured at a selected pump current, from which the optimum diameter of the gas intake orifice can be calculated from the deviations from the ideal values using a simple ratio.

Abstract: An exhaust gas sensor includes a housing and a sensor element supported by the housing. The sensor element includes a support member having an exhaust side, a reference side, and an aperture extending through the support member between the exhaust side and the reference side. The sensor element further includes an exhaust-side electrode on the exhaust side of the support member. The exhaust-side electrode is electrically connected to a contact on the reference side of the support member via a lead extending through the aperture. The aperture is sealed around the lead such that gas cannot pass through the aperture. The support member is oriented substantially parallel to the flow of exhaust gases when the exhaust gas sensor is installed on a vehicle. The sensor further includes a contact pin in the housing that engages the contact and biases the sensor element against a portion of the housing.

Abstract: An oxygen sensor includes a detector to be positioned between the ambient air and the exhaust gas, which generates a voltage corresponding to a difference in oxygen partial pressure therebetween. A controller performs monitoring of the output voltage from the oxygen sensor and determines an occurrence of fracture in the detector when detecting the generation of a lean signal, which is a signal indicating the above-described difference in the oxygen partial pressure is small, being frequently more than a certain value, and carries out an abnormality diagnosis to the oxygen sensor.

Abstract: A device according to the present invention is provided with element temperature measurement voltage application circuit for temporarily applying a predetermined voltage for element temperature measurement to a sensor element of an air-fuel ratio sensor equipped to an exhaust system of an internal combustion engine, first sensor output reading circuit for reading in a sensor output just before applied with the voltage, and second sensor output reading circuit for reading in a sensor output being applied with the voltage, wherein the element temperature of the air-fuel ratio sensor is estimated based on the sensor output just before applied with the voltage and the sensor output being applied with the voltage. Further, during internal resistance measurement of the sensor element of the air-fuel ratio sensor equipped to the exhaust system of the internal combustion engine, a voltage applied to the heater for heating the sensor element is maintained to be constant.

Abstract: Disclosed herein is a gas sensor and a method of making a gas sensor comprising disposing a reference electrode on an inner surface of an electrolyte; sputtering a sensing electrode on an outer surface of the electrolyte; sputtering a zirconia layer on a side of the sensing electrode opposite the electrolyte, wherein the zirconia layer has a thickness of about 20 nanometers to about 1 micrometer, and disposing a protective layer on a side of the zirconia layer opposite the sensing electrode.

Abstract: An exhaust gas dilution apparatus 10-2 is the same form multi-venturi type comprising a rectifier 11, divider 12, exhaust chamber 14, dilution tunnel 15, and a divider pipes 13t on the dilution side of a tunnel 15 side. All divider pipes 13 are provided with a venturi 21 having the same performance inserted in the same position, to measure the flow rate in the dilution tunnel and the flow rate on the exhaust pipe side. The opening of the shutter 19 provided in the exit of the exhaust chamber 14 is controlled so that the two flow rates are equivalent.

Abstract: An electrochemical sensor element for determining the oxygen concentration in exhaust gases of internal combustion engines is described. The sensor element has a pump cell, which has a pump electrode situated on a surface of the sensor element facing the gas mixture, and a measuring gas electrode situated in a measuring gas area, the gas mixture entering the measuring gas area through a diffusion resistor. In addition, the sensor element has a reference electrode situated in a reference gas area. Another diffusion resistor is provided between the measuring gas area and the reference gas area.

Abstract: One embodiment of a gas sensor shield comprises: an elongated body comprising solid sides and a tip disposed across one end of said shield; and an opening disposed within said tip, wherein said opening comprises at least two elongated apertures.

Abstract: A method is presented for determining the fuel/air ratio in the individual cylinders (single cylinder lambda) of an internal combustion engine having a plurality of cylinders, whose exhaust gases mix together in a common exhaust gas pipe system, from the signal of an exhaust gas probe, whose mounting location lies in the common exhaust gas pipe system, with the aid of an invertible model for the intermixing of the exhaust gases at the mounting location of the exhaust gas probe. The method is distinguished in that, in the determination of the single cylinder lambda from the signal of the one exhaust gas probe evaluated with the aid of the inverted model, the rotational angle position of the exhaust gas probe at its mounting position is taken into consideration.

Abstract: A method of filtering an oxygen sensor signal is provided. The method includes obtaining the oxygen sensor signal from the oxygen sensor on a periodic basis. The oxygen sensor signal is then compared to an average oxygen sensor signal value. If the oxygen sensor signal is greater than the average oxygen sensor signal value, a high signal counter is incremented. If the high signal counter is greater than a high signal count threshold, the oxygen sensor signal is forced to a high signal value. If the oxygen sensor signal is less than the average oxygen sensor signal value, a low signal counter is incremented. If the low signal counter is greater than a low signal count threshold, the oxygen sensor signal is forced to the low signal value. The high and low signal count thresholds correspond to a preselected period of time indicating a low or high signal trend within the oxygen sensor signal.

Abstract: A gas sensor includes an element case 42 with an internal peripheral surface formed as a taper surface 100. A portion of a housing section 43 surrounded by the taper surface 100 and a protective film 48 is filled with a filler 49. When the filler 49 thermally expands at high temperature, the filler 49 is subjected to a component of force in an upward direction by the taper surface 100. Therefore, projection of an element portion 44 involving deformation of the protective film 48 is suppressed, a change &Dgr;L of a propagation distance L to a reflecting section 33 is also suppressed, and a detection accuracy never decreases. In addition, reverberation is reduced.

Abstract: An air-fuel ratio sensor is equipped with a sensing element including a solid electrolytic substrate. When the sending element is warmed up and activated by a heater, a microcomputer controls electric power supplied to the heater based on a control base value being set according to a duty ratio=100%. A power profile P1 is determined beforehand to set a target heater power. Through the warm-up heater power control, an actual heater power supplied to the heater is equalized to the target heater power determined according to the power profile P1.

Abstract: A method of determining the type of fuel being burned in an engine by analyzing the signal provided by a exhaust gas oxygen sensor signal is disclosed. The determination is based on the ratio of the value of certain characteristics of the signal during the lean and rich portions of the signal.

Abstract: A second protective layer is a ceramic porous protective layer comprising coarse particles and fine particles structurally arranged in such a manner that interparticle cavities formed between the coarse particles are filled with the fine particles. At least either of the coarse particles and the fine particles contain at least one selected from the group consisting of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3 and solid solution having the same crystal structure as those of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3.

Abstract: A method and apparatus for controlling the operation of a “lean-burn” internal combustion engine in cooperation with an exhaust gas purification system having an emissions control device capable of alternatively storing and releasing an exhaust gas constituent, such as NOx, when exposed to exhaust gases that are lean and rich of stoichiometry, respectively, wherein a measure of the efficiency of the device to remove the exhaust gas constituent from engine exhaust gas is determined, and a purge event for releasing previously-stored NOx is initiated when the efficiency measure falls below a threshold value.

Abstract: A state quantity &sgr;(n) of a switching function is calculated based on a predetermined target air-fuel ratio TGABF, a detected air-fuel ratio AFSAF detected by a sensor (16), and a state equation derived from a transfer function Geng(q) of a secondary discrete system, representing the correlation between an air-fuel ratio of an air fuel mixture in a combustion chamber (1A) and the detected air-fuel ratio (S14). The air-fuel ratio is feedback corrected by applying a sliding mode control process based on the difference between the target air-fuel ratio TGABF and the detected air-fuel ratio AFSAF, and the state quantity &sgr;(n) (S14-S21). The response and robustness of the air-fuel ratio control are enhanced by using a physical model of the secondary discrete system.

Abstract: A gas sensor is provided which includes a first cylindrical insulation porcelain having a gas sensor element installed therein and a second cylindrical insulation porcelain disposed in contact with the first insulation porcelain. The first insulation porcelain is disposed on a seat surface formed on an inner wall of a housing through a packing ring. A contact between the first and second insulation porcelains being located within a contact permissible range defined by projecting outer and inner edges of the packing ring onto an end surface of the first insulation porcelain, thereby minimizing a lateral shift between the contact and the packing ring to avoid the breakage of the first insulation porcelain during assembly or use of the gas sensor.

Abstract: A failure diagnostic apparatus for an air-fuel ratio detecting device has an exhaust emission purifying device provided in an exhaust passage; an air-fuel ratio detecting unit for detecting the air-fuel ratio of an exhaust gas from the purifying device; a first determination unit for determining that the air-fuel ratio is estimated to be rich for longer than a first predetermined period of time; a second determination unit for determining that the air-fuel ratio is estimated to be lean for longer than a second predetermined period of time; and a failure diagnosis device for determining that the air-fuel ratio detecting device has failed if a variation in the air-fuel ratio, calculated based on the detected air-fuel ratios until both the first and second determination units make the determinations, is equal to or less than a predetermined value.

Abstract: A method is provided for checking the dynamic behavior of a measuring sensor which detects a substance concentration in the exhaust tract of an internal combustion engine operating with excess air, downstream of an NOx storage catalytic converter. A signal from the measuring sensor is monitored during a regeneration phase. When a predetermined signal profile is absent, a faulty dynamic behavior is diagnosed.

Abstract: According to the present invention, there is provided: a sensor element including an oxygen concentration detection section consisting of solid electrolyte for outputting a detection signal corresponding to an oxygen concentration in a hollow chamber to which an exhaust of an internal combustion engine is introduced and an oxygen pump section for controlling an electric current to be applied to a solid electrolyte wall that divides the hollow chamber from an exhaust side of the engine so that the oxygen concentration in the hollow chamber becomes a predetermined oxygen concentration, to flow oxygen into/out of the hollow chamber; an air-fuel ratio detection circuit for outputting an air-fuel ratio detection value based on the electric current applied to the solid electrolyte wall by the oxygen pump section; and a pump current cut off circuit for cutting off the power supply to the solid electrolyte wall by the oxygen pump section, and a detection value of air-fuel ratio is corrected based on an output value o

Abstract: The present invention is to detect a temperature of an exhaust gas purification catalyst in order to determined an air-fuel ratio feedback control start time of an internal combustion engine, wherein the temperature of the exhaust gas purification catalyst is detected by estimation and computation based on an element impedance of an air-fuel ratio sensor.

Abstract: A process for cleaning exhaust gas flow from an internal combustion engine using a catalyst, a lambda probe is disposed in the exhaust gas flow upstream from the catalyst and is connected to a controller that actuates the lambda probe, the controller receives a raw signal output from the lambda probe and forms a measurement signal that is supplied to control the internal combustion engine. The process includes regulating operation of the internal combustion engine such that a predetermined value of the lambda probe corresponds to a certain level of the measurement signal. Trimming the certain level of the measurement signal by a set value determined with an additional measuring pickup located downstream of the catalyst is performed, the trimming corrects the certain level of the measurement signal that corresponds to the predetermined value of the lambda probe.

Abstract: The present invention provides a method for easily measuring nitrogen oxide concentration of an engine vehicle emission. The method can measure vehicle emission from an engine of a vehicle in travel with high precision even in regions other than the lean region, that is, regions from the stoichiometrical region to the rich region by using a NOx sensor exclusively used for the lean region. The present invention has an arrangement in which a NOx sensor that is exclusively used for the lean region is installed in an exhaust pipe 3 connected to the engine 2. Air (secondary air) A is introduced into the exhaust pipe 3 on the upstream side of the NOx sensor 6 so that the NOx sensor 6 is allowed to measure the concentration of NOx in the engine vehicle emission diluted by air A. Thus, the NOx concentration in the engine vehicle emission before dilution G is obtained by using the measured value of the NOx concentration after dilution and by using a dilution ratio.

Abstract: Device with a sensor arrangement for determining the ambient-air quality and an arrangement of ozone sensors upstream and downstream of a radiator which is coated with a catalyst material, and method for operating a device of this type

Abstract: Devices for determining at least one parameter of a flowing medium according to the related art do not offer sufficient protection of a measuring element from contamination by foreign particles. A device (1) is disclosed having an element (55), for example in the form of a bulge (60), in the channel (20) in which the measuring element (10) is positioned, which deflects the foreign particles and thus protects the measuring element (10).

Abstract: A system for regulating the fuel-air mixture in a multi-cylinder internal combustion engine. The system utilizes binary sensors to detect relative deviations from stoichiometric combustion, including individual combustion events, and allows for regulation to achieve optimal and similar combustion to take place in all the cylinders.

Abstract: A voltage sensing system that has a pair of input leads having a first input lead, and a second input lead each sensing a non-grounded voltage, and an amplifier coupled to the pair of input leads, the amplifier generating an amplifier output voltage in response to a voltage on the first input lead, a voltage on the second input lead and an offset voltage. The system further includes a controller for receiving the amplifier output voltage and determining an operating range, and an offset voltage generator for generating the offset voltage, the offset voltage generator altering the offset voltage in response to the operating range determined by the controller. An oxygen sensing system using a sample resistance for sensing a bi-directional current may be coupled to the voltage sensing system. A method for sensing air-to-fuel ratio includes sampling an input voltage drop derived from a pumping current across a sampling resistance. The input voltage is indicative of air-to-fuel ratio.

Abstract: A proportional oxygen sensor, a three-way catalyst, a binary O2 sensor, a NOx purification device, and a binary O2 sensor are positioned in the named order in the exhaust system of an internal combustion engine. A correction coefficient KMON2, which is set in accordance with the degree of deterioration of a three-way catalyst, is used to correct the timer value tmMON2 used to measure the time extending from the time at which the output of the O2 sensor is changed when the air-fuel ratio is increased, until the time at which the output of the O2 sensor is changed. When the corrected timer value tmMON2 is smaller than a reference time TNOxREF, it is ascertained that deterioration of the NOx purification device has occurred.

Abstract: An apparatus for controlling operation of a heater has an internal resistance detector for detecting an internal resistance value of an oxygen sensor, and a control unit for estimating a surface temperature of the oxygen sensor based on the internal resistance value detected by the internal resistance detector, then estimating a temperature of the exhaust pipe based on the estimated surface temperature of the oxygen sensor and controlling the operation of the heater, which is combined with the oxygen sensor in a single unit, when the estimated temperature of the exhaust pipe has reached a predetermined temperature.

Abstract: An oxygen concentration sensor element impedance detecting apparatus and method that maintains sensor detection accuracy by shortening the sweeping time period of an element impedance detecting voltage. A sub-microcomputer performs at least two sweeping actions for switching an element application voltage Vo from a reference voltage to a sweeping voltage when it once detects the element impedance of the oxygen concentration sensor AFS, and A/D converts only one of the element application voltage Vo and an element current detecting voltage Vi during the sweep, to shorten the sweeping time period. A sensor drive circuit prevents the element application voltage Vo from being changed by the element current. Even if element application voltage Vo detection and element current detecting voltage Vi detection are performed by separate sweeps, detection results substantially identical to those of the case in which detection of those two voltages are performed during one sweep are obtained.

Abstract: The major part of the hazardous material quantities emitted by motor vehicles having an exhaust gas catalytic converter accrues in the start-up phases in which the catalytic converter is not yet at the operating temperature. The catalytic converter first begins to operate after it is heated up to the light-off temperature. The heat-up times must be kept as short as possible. With aging of the catalytic converter, the light-off temperature gradually increases, and thus, the heat-up time as well as the emitted hazardous material quantity also increases. In order to monitor the catalytic converter and thus the major part of the hazardous material emission, the light-off temperature must be repeatedly measured. Since this temperature cannot be read out clearly from the temperature-time curve of the catalytic converter after the start-up of the motor, the signal of a sensor for oxygen, carbon dioxide, water vapor, or combustible materials in the exhaust gas is additionally observed.

Abstract: A gas concentration measuring apparatus is provided which may be employed in measuring an air-fuel ratio of mixture sucked into automotive engines. The apparatus includes a gas concentration sensor exposed to a gas and a voltage applying circuit. The gas concentration sensor is responsive to application of voltage to produce a current signal indicative of concentration of the gas. The voltage applying circuit includes an operational amplifier which operates on a source voltage and which outputs the voltage for developing the voltage applied to the gas concentration sensor which has a level changing as a function of voltage inputted to the operational amplifier.

Abstract: A gas concentration measuring apparatus is provided which measures the concentration of two kinds of gas components such as O2 and NOx contained in exhaust gasses of an internal combustion engine of automotive vehicles. The apparatus has a gas sensor which includes a first cell responsive to application of a voltage to discharge O2 in the exhaust gasses to the outside and produce an electric current as a function of concentration of the discharged O2 and a second cell responsive to application of a voltage to produce an electric current as a function of concentration of NOx in the exhaust gasses from which the O2 is discharged by the first cell. The apparatus offsets an error component of the electric current produced by the second cell which depends upon O2 contained in the exhaust gasses.

Abstract: A diagnostic apparatus for a vehicle can display diagnostic results and an indication of whether or not the diagnosis has been completed with a single display device. The diagnostic apparatus adapted to be mounted on the vehicle for diagnosing the vehicle based on driving condition parameters of the vehicle includes a display device or an indicator for indicating presence or absence of malfunction based on the diagnostic results, means for switching the diagnostic apparatus into a notification mode in response to a predetermined operation state, and a display control unit for displaying on the display device the indication of whether or not the diagnosis has been completed in response to being switched into the notification mode. The indication of whether or not the diagnosis has been uncompleted can be displayed on the display device by switching into a notification mode in response to the predetermined operation status.

Abstract: This description refers to a device for analyzing the most important environmentally relevant substances, such as CO, HC and NO, that are present in vehicle exhaust emissions. It is based on the principle of IR gas absorption. This involves producing measuring signals and a reference signal in a measured optical length (stainless steel tube), with the aid of an infrared source and detector. The production of a ratio then gives a reading and a warning signal is produced whenever a certain limit value is exceeded. The OBM system is made up of modular components, such as a sampling device, exhaust gas processing unit, analyzing device and evaluation unit, which are built into the vehicle. The fluctuating conditions present in the vehicle are compensated for by robust construction and correction of temperature drift by means of production of the first derivation and readjustment of signal strength using an electronically regulated amplification control.

Abstract: A heater pattern for a heater of a gas sensor in which a temperature profile is manipulated utilizes a thermistor element arranged in an electrically serial configuration and disposed on a substrate. The thermistor element is arranged so as to define an edge pattern extending about a perimeter of the substrate and a center pattern serially connected to the edge pattern. The center pattern extends over a portion of the substrate that is intermediate the perimeter of the substrate. In a preferred embodiment, the thermistor element is screen printed onto the substrate to a thickness of about 5 microns to about 50 microns, and preferably to a thickness of about 10 microns to about 40 microns. The edge and center patterns are furthermore preferably formed of materials having differing coefficients of thermal resistivity, e.g., platinum and platinum/palladium blends.