Papers by Keyword: Oxygen Sensor

Abstract: A ZrO₂/Al₂O₃ (molar ratio of 1: 1, ZA) composite ceramic was formed by slip casting as solid electrolyte in a zirconia oxygen sensor. The bonding of the ZA ceramic green body to 95% Al₂O₃ ceramic green body support tube was carried out at 900 oC for 60 min by the gradient joining technique using pure Al₂O₃ slurry as the interlayer. Subsequently, the Pt slurry was coated on the surface of the pre-sintered composite ceramic, and then co-sintered at 1550 oC for 60 min to fabricate a Pt/ceramic composite probe. The interface microstructure and bonding mechanism were briefly investigated, and the electrical conductivity of the probe was tested. The experimental results show that the two high-quality ZA/Al₂O₃ and ZA/Pt interfaces were obtained. In particular, the relationship between the logarithm of conductivity (lnρ) and the reciprocal of temperature was well in accord with the Arrhenius equation. The Pt/ceramic composite probe presented the typical characteristic of high-temperature ionic conduction.

Abstract: Flow corrections established based on Lambda control system of spark ignition engines, determines in a decisively way the quality of air-fuel mixture. Faults in the operation of the control system generates deviations of the mixture composition from stoichiometric report, in this way affecting the entire combustion process in engine cylinders. This phenomenon leads, among others, to changes regarding the density of pollutant emissions from exhaust gases. In this context, this paper presents experimental researches made using the simulation of faults that may occur in the control system to highlight their influence on the concentration of engine emissions.

Abstract: The measurement of oxygen content in liquid iron and steel has been a challenge for decades and there have been many attempts to develop oxygen sensor to adjustment the smelting process on the basis of the probe for monitoring oxygen dissolved in molten liquid. However, there was still not a common standards of zirconium tubes about domestic product, which limited their application and improvement This work selected several domestic enterprises oxygen measuring half-cell system to study the relationship between the physical properties and microstructure at room temperature. Furthermore, we also analyzed about the typical performance of the domestic Oxygen content products, which would be beneficial to test and improve the quality of domestic products. Keywords: zirconia tubes, oxygen content, oxygen sensor

Abstract: Effects of a metal oxide structure on the oxygen sensing properties are investigated. In the existence of the etched V-groove gallium oxide geometry, its electrical and sensing properties, i.e., high sensitivity and response time areinvestigated. Grain sizes of the material are dependent on different sputtering conditions and investigated by AFM. Under the partial-voltage circuit measurement, it can be confirmed that the increase of temperature will result in the increase of resistance for the Ga₂O₃ oxygen sensor. From experiment, good stability and repeatability of the oxide sensor are demonstrated when tested under oxygen concentration. These properties show that the oxide structure has a good potential for high sensitivity oxygen sensor.

Abstract: The air-fuel ratio (AFR) control becomes an important research direction in gas engine. This article conducts air-fuel ratio (AFR) closed loop control research in a CNG engine. The injection pulse width of gas is controlled by a controller, oxygen sensor signal as a feedback signal. In order to make the engine can achieve the anticipated air-fuel ratio under different conditions; we adopt fuzzy self-tuning PID control strategy based on feed forward control. We transformed a 2135G diesel engine into the single fuel gas engine. Experimental investigation on the effect of air-fuel ratio closed loop control .Experimental results shows that, fuzzy self-tuning PID control strategy can control CNG engine air-fuel ratio working in the good condition.

Abstract: This paper presents a study and investigation of an improvement of boiler efficiency with an automatic control of air quantity into a combustion chamber. A fire tube boiler with a fixed gate and screw conveyor for feeding fuel was used to test the automatic control system, and a sub-bituminous was used as a fuel for this study. The increase in boiler efficiency was based on controlling amount of air quantity for fuel combustion before entering to the combustion chamber using fuzzy logic control algorithm. Automatic combustion control was achieved by measuring the amount of Oxygen gas (O₂) from flue gas stack. From the experimental results, it was indicated that the automatic control system can control the average amount of O₂ in flue gas at 11.09% when the O₂ in the flue gas was set at 10%. The boiler efficiency was increased by 4.34%, and the energy consumption was reduced to have a fuel saving of 195.88 ton/year.

Abstract: Oxygen plays a fundamental role in nature and industrial process, the fast on-line oxygen concentration detection is of great significance. Tunable diode laser absorption spectroscopy (TDLAS) is capable high selective, high sensitive, non-intrusive, this technique exploits the diode laser tunable and narrow bandwidth characteristics, by selecting one absorption line of the target gas to avoid interference from other gas and realize oxygen concentration fast on-line detection. In this paper, we use vertical cavity surface-emitting laser (VCSEL) as the light source, adopting the wavelength modulation spectroscopy and the harmonic detection technology to measure the second harmonic signal and realize oxygen concentration fast on-line detection. The detection concentration range between 0.1% to 40% and detection accuracy is 0.1%.

Abstract: The fabrication and operation of a new thick film type of limiting current oxygen sensor is demonstrated that utilizes YSZ as oxygen ion conducting solid electrolytes and La_0.75Sr_0.25Cr_0.5Mn_0.5O_3-δ +60% YSZ as dense diffusion barrier. The oxygen sensor shows a near linear response between 0 to 10ppm O₂ in argon at 973K.

Abstract: The fabrication and operation of a new thick film type of limiting current oxygen sensor is demonstrated that utilizes yttria (8% mol) stabilized zirconia (YSZ) as oxygen ion conducting solid electrolytes and dense La_0.8Sr_0.2CoO₃ (LSC) as diffusion barrier. The oxygen sensor shows a near linear response between 0 to 10.5% O₂ in argon at 1023K. The advantages of the sensor are simple construction, low cost and potential long term stability.

Abstract: Planar zirconia automotive oxygen sensor consists of three layers of ZrO2 tape-casting substrates which possess different function after sintering, so it is important for us to research the joining of these substrates. Through SEM and EDS measurements, the essay mainly discussed the joining of ZrO2 tape-casting substrates and the adhesive mechanism when chose ZrO2 slurry as joining materials.