摘要:
A sensor for determining gas components and/or gas concentrations in gas mixtures, in particular in exhaust gases of internal combustion engines. The sensor has an oxygen pump cell and a measuring element having a sensitive region. Provided between the pump cell and the gas mixture is a diffusion path in which there are formed an oxygen gradient XO.sub.2 and a gradient X.sub.CO of the gas component to be determined, which extend respectively in opposite directions. The measuring element is positioned relative to the pump cell and the diffusion path in such a way that an excess of oxygen is present on the sensitive region of the measuring element.
摘要:
A sensor arrangement for determining at least one of gas components and gas concentrations of gas mixtures including CO, NO.sub.x and HC in exhaust gases of internal combustion engines, includes a measuring element which has a sensitive region; and a pump cell that includes a solid electrolyte and inner and outer pump electrodes which are opposingly disposed at least on the solid electrolyte and which effect an oxygen transfer to the measuring element, wherein the pump cell and the measuring element are spatially separated from one another, are located in different temperature zones during operation of the sensor arrangement, and are connected to one another by a diffusion segment through which oxygen can diffuse from the pump cell to the measuring element.
摘要:
A method of determining at least one of gas constituents and gas concentrations of a gas mixture such as exhaust gas from an internal combustion engine includes producing a change in gas concentration of the gas mixture at a semiconductor gas sensor by pumping a variable supply of oxygen to the semiconductor gas sensor by means of a solid electrolyte pumping cell; detecting at least one reaction speed selected from the group consisting of adsorption speed and desorption speed caused by the change in gas concentration as a signal from the semiconductor gas sensor which is a reply function; evaluating the signal from the semiconductor gas sensor over time to provide a time response of the reply function; and comparing the time response of the reply function with a stored, standardized time response of different gas constituents whereby at least one of the gas constituents and the gas concentrations of the gas mixture are determined.
摘要:
In order to provide a method and arrangement for analytical determination of the relative amounts of exhaust gas components, except for water, but including hydrogen in the rich range or oxygen in the lean range, and for determining a &lgr; value, in which the exhaust gas sample can be taken at any arbitrary location, an arrangement is provided in which at least one portion of the exhaust gas is passed through a catalytic reactor (2, 22), a condenser (3,23) connected to the catalytic reactor to receive the gas passed through it, and, after passing through the condenser, the gas passes through an IR spectrometer and by a &lgr;-sensor. The oxidizable and reducible components of the exhaust gas are reacted with each other in the catalytic reactor which is heated to temperatures greater than 450° C. The relative amounts of CO2, hydrocarbons and, if present, CO are measured with the IR spectrometer and either the relative amount of hydrogen in the rich range or of O2+½ NO in the lean range is determined with the help of the signal (Ip) from the &lgr;-sensor. A &lgr; value is calculated from the measured exhaust gas component concentrations or relative amounts.
摘要:
The invention is directed to an arrangement for detecting the oxygen content in the exhaust gas of an internal combustion engine. The arrangement includes a concentration measuring cell operating pursuant to the Nernst principle. The concentration measuring cell has a measuring electrode, a solid electrolyte and a reference electrode and a series circuit which includes a direct voltage source and a series resistor. The series circuit connects the measuring electrode to the reference electrode. The measuring electrode communicates with the exhaust gas of the internal combustion engine and is connected to the reference electrode via the solid electrolyte. The reference electrode communicates with the reference gas volume. The reference gas volume is partitioned from the exhaust gas and from the ambient air so that a particle exchange between the reference gas volume and the exhaust gas as well as between the reference gas volume and the ambient air is at least made more difficult. The output voltage of the concentration measuring cell defines a measure for the difference of the oxygen concentrations in the exhaust gas of the engine and the reference gas volume. The output voltage of the direct voltage source and/or the value of the series resistance is so pregiven that an electric current Ip is always so directed that oxygen is transported from the exhaust gas to the reference gas volume independently of the output voltage of the concentration measuring cell. The current Ip flows in a current circuit including direct voltage source, series resistance and concentration measuring cell.
摘要:
The invention relates to a measuring sensor having an internal pump oxygen reference atmosphere which, in turn, has a device for compensating pressure which is so dimensioned that, on the one hand, mechanical damage because of overpressure in the reference volume is reliably prevented and, on the other hand, external influences on the composition of the pumped measured gas atmosphere are substantially excluded. The device for compensating for pressure is so dimensioned according to the invention that the particle exchange between ambient air and gas to be measured is opposed by a resistance which is defined by the limit current principle.
摘要:
A gas sensor and a method for its manufacture are described. The gas sensor has a solid electrolyte having at least one measuring electrode and one porous protective coating. The measuring electrode has an electrically conductive base layer and a further layer, the further layer god being deposited in the pores of the porous protective coating adjacent to the base layer via galvanic deposition. In order to deposit the further layer via galvanic deposition, the basic body, which has been fused with the base layer and the protective coating via vitrification, is immersed in a galvanizing bath, the base layer being connected as the cathode.
摘要:
An electrochemical sensor determining a gas concentration of the measuring gas. The sensor has an electrochemical element including a first solid electrolyte body having an electrochemical pump cell and a first (external pump) and a second (internal pump) electrode and having a gas chamber which is connected to the measuring gas chamber via a gas supply opening and in which the second electrode is arranged. The electrochemical element also includes a second solid electrolyte body having an electrochemical sensor cell (e.g., a Nernst cell) and a third and fourth electrode, each electrode having a lead for the electrical contacting. The leads of the first and second electrodes are decoupled capacitively from the lead of at least the fourth electrode by a device.
摘要:
The invention is directed to a method of operating an exhaust-gas probe having a pumped reference atmosphere in a relatively closed volume. In this method, the oxygen ion current, which carries the pump current Ip to the reference atmosphere, is temporarily increased under specific conditions. In this way, an adulteration of the reference atmosphere can be more rapidly eliminated. This adulteration can occur because of fuel particles which diffuse in.
摘要:
An electrochemical sensor for ascertaining a gas concentration of a measuring gas includes an electrochemical element, including a first solid electrolyte body having an electrochemical pump cell and a first and a second electrode, and having a gas compartment which is connected via a gas access opening to the measuring-gas compartment, and in which one of the two electrodes is arranged. The electrochemical element further includes a second solid electrolyte body having an electrochemical sensor cell (Nernst cell) and a third and a fourth electrode. The surface of the first solid electrolyte body faces the measuring-gas compartment, and the gas access opening is covered by a porous protective layer. The electrochemical sensor includes a layer that exhibits a higher density or a lower porosity compared to the protective layer and that is allocated to the porous protective layer.