Oxygen sensors schematic

Fig. 11.29 Schematic diagram of the oxygen sensor for a lean burn engine (Soejima and Mase, 1985).

While a number of designs have been used, most oxygen sensors for automotive applications consist of a hollow, closed end tube, a schematic of which is shown in Figure 2. As shown, the interior of the closed end tube is open to the atmosphere which serves as a constant or reference oxygen partial pressure while the exterior is exposed to the exhaust gas. The voltage signal produced by the electrolyte is sensed by electrodes on the inner and outer surface of the sensor. These, in turn, are connected to the electronics package of the closed loop system. 

Figure 1. Schematic of oxygen sensor solid electrolyte galvanic cell...

Figure 6 is a schematic of a closed loop system. It consists basically of an oxygen sensor to monitor the exhaust air-fuel ratio, a "black box" electronic control system, a carburetor or fuel injector which is controlled and adjusted by the "black box" and, finally, a three-way or dual bed converter. The signal from the oxygen sensor is monitored continuously by the electronics package which then adjusts the carburetor or fuel injector to control the air-fuel ratio at stoichiometric. 

A cross-section schematic drawing of the newly-developed thick film oxygen sensor is shown in Figure 2. The platinum film heater is embedded in the alumina substrate. Electrical resistance of the heater is about 6 ohms at room temperature. 

Figure 1. Schematic drawing and voltage curve for crucible-type oxygen sensor...

Figure 2. Schematic drawing of thick film oxygen sensor...

Schematic diagram of oxygen concentration cell (Oxygen sensor)...

Figure 11. Electrodes in microcalorimetric vessels. A Schematic diagram of a section through a titration-perfusion microcalorimetric vessel equipped with a polarographic oxygen electrode and a pH electrode, a, sample compartment, volume 3 ml b, hollow stirrer shaft c, steel tube d, turbine stirrer e, O-rings f, combination pH electrode protected by a steel tube g, polarographic oxygen sensor (Clark electrode). B Record from a growth experiment with T-lymphoma cells. The vessel was completely filled with medium. Once the baseline had been established, the experiment was started (as indicated by the arrow) by the injection of 100 pi concentrated cell suspension.

A common type of oxygen sensor takes the form of an yttria stabilized zirconia (YSZ, see earlier) tube electroded on the inner and outer surfaces with a porous catalytic platinum electrode. The electrode allows rapid equilibrium to be established between the ambient, the electrode and the tube. Such a system is shown schematically in Fig. 4.36. 

Another important application is in the refining of steels when the oxygen content must be controlled at the parts per million level and monitored continuously on line and many oxygen sensors are currently used in the steel industry for this purpose. The principle of operation is as described for the lambda sensor and one form is shown schematically in Fig. 4.39. In this case the reference activity is established by a chromium metal/chromium oxide mix rather than being defined by air. 

Figure 4-17 Schematics of various implantable electrochemical/optical sensors useful for continuous in vivo monitoring (A) catheter style amperometric oxygen sensor (B) design of Paratrend intravascular combined PO2, PCO2, and pH sensor (hybrid electrochemical/optical design) (C) needle type electrochemical glucose sensor useful for monitoring glucose subcutaneously to track blood glucose levels continuously.

Andreescu et al. introduced a 96-electrode well-type device enabling oxygen sensing for monitoring respiratory activity of biological cells.65 65 The principal set-up of the multichannel dissolved oxygen sensor system (DOX-96) is schematically in shown in Fig. 14.13. This highly parallelized approach shows successful... 

A schematic representation of how a decrease in oxygen tension (hypoxia) may affect carotid body glomus cell function. In the mitochondrial model, hypoxia affects either reactive oxygen species (ROS) production or ATP production of mitochondria. Both of these may affect the outward flux of potassium via the potassium channel with the downstream effects shown in the diagram. In the membrane model, the ROS production by membrane-bound molecules (cytochromes) is oxygen sensitive, and thereby affected by hypoxia. Thus, these membrane-bound molecules function as proximal oxygen sensors and cause effects on potassium channels with the downstream effects described in the figure and in the text... 

FIGURE 2.3 Schematic presentation of the interaction of the solid electrolyte oxygen sensor with gas environment 1-6 stages of interaction. (From Zhniykov, S., Mathematical model of electrochemical gas sensors with distributed temporal and spatial parameters and its transformation to models of the real YSZ-based sensors. Ionics 12 (2006) 135-148. With kind permission of Springer Science and Business Media.)... 

Figure 15.6 A schematic of a flashlamp-excited oxygen sensor system. Items are 10, optical fiber 12, fiber input/output end 14, fiber-sensor interface 16, sensor 54, 56, reference and signal detectors 42,46,52, 55, lenses 44, short-wavelength pass excitation filter 48, beam splitter 50, excitation wavelength rejecting and emission wavelength separation means 40, 58, 60, electronic signal processing means. (From the patent of Hauenstein et al [12].)...

Fig. 3.7. Schematic of the structurally integrated OLED-based oxygen sensor (not to scale). The photodetector, a PMT or Si photodiode, is behind the OLED pixel array. The Ti02 nanoparticles, which are embedded in the dye PS-sensing film, act as a scattering medium, increasing the absorption of the EL by the dye...

A schematic of the oxygen sensor is shown in Fig. 5.1(a). Figure 5.1(b) shows the device had a strong response when it was tested at 120°C in pure... 

FIGURE 11.17 Schematic of a ZrOj-based oxygen sensor and an actual sensor unit. 

Figure 1. (a) Fluorescence lifetime measurement using phase-modultion fluorimetry. (b) Schematic of phase fluorimetric oxygen sensor. 

Figure 19. Schematic diagram of a Clark-lype oxygen sensor a)Cathode b) Anode c) Insulator d)Electrolyte e) Membrane f) Stirrer g) Sample for analysis...

Fig. 14-1. Schematic diagramme of (a) a membrane covered dissolved oxygen sensor and (b) diffusion ranges between cathode and outer solution.

A reducing gas can also be analyzed indirectly by first oxidizing it, for instance, with an excess of oxygen produced by an oxygen pump (I = constant). The Oj excess is then measured by an amperometric oxygen sensor.A schematic representation is given in Figure 10.13. 

Fig. 1. Schematic drawing of oxygen sensors (a) conventional type (air reference electrode), (b) minisensor with Pd-PdO reference system, (c) sensor with zirconia tip measuring electrode, [Fouletier, 1982/83].

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