The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Nobuyuki Kawahara - One of the best experts on this subject based on the ideXlab platform.

  • Local fuel Concentration Measurement through spark-induced breakdown spectroscopy in a direct-injection hydrogen spark-ignition engine
    International Journal of Hydrogen Energy, 2016
    Co-Authors: Kazi Mostafijur Rahman, Nobuyuki Kawahara, Eiji Tomita, Daichi Matsunaga, Yasuo Takagi, Yuji Mihara
    Abstract:

    Abstract Quantitative Measurements of local fuel Concentrations were conducted in a direct-injection hydrogen spark-ignition research engine using the spark-induced breakdown spectroscopy (SIBS) technique. For SIBS Measurements, a new sensor was developed from a commercially available M12-type spark plug with no major modifications to the electrodes. The new plug sensor showed better durability and required less maintenance when used in a hydrogen research engine. Emission spectra from the plasma generated by the spark plug were collected through an optical fibre housed in the centre electrode of the plug and resolved spectrally for atomic emissions of Hα, O(I), and N(I). The main focus of the present work was to characterise the effects of ambient pressure at ignition timing on spectral line emissions and to improve the accuracy of SIBS Measurements by taking into account the pressure dependency of atomic emissions. A significant effect of the corresponding pressure at ignition timing was observed on spark-induced breakdown spectroscopic Measurements and emission line characteristics. Retarded spark timing (i.e. higher ambient pressure at the ignition site) resulted in lower spectral line intensities as well as weaker background emissions. It is well established that with relatively higher pressure and density of atoms or molecules, the cooling of expanding plasma accelerates, and the collision probability increases, leading to both a weaker broadband continuum and atomic emissions. A “calibration MAP” representing the correlation of air excess ratio (relative air/fuel ratio) with both intensity ratio and pressure at ignition timing was created and subsequently used for quantitative Measurements of local fuel Concentrations for both port injection and direct injection strategies to demonstrate and explore the effects of pressure dependency of atomic emission on the accuracy of the SIBS Measurements. Local stratification of the fuel mixture in the vicinity of the spark gap location associated with direct injection strategies was confirmed; the coefficient of variation of the local air excess ratio was relatively small for Measurements made using the calibration map. This demonstrated that the Measurement accuracy of local fuel Concentrations through a spark plug sensor can be improved significantly when the pressure dependency of atomic emissions is taken into account.

  • fuel Concentration Measurement of premixed mixture using spark induced breakdown spectroscopy
    Spectrochimica Acta Part B: Atomic Spectroscopy, 2009
    Co-Authors: Nobuyuki Kawahara, Eiji Tomita, S. Takemoto, Y. Ikeda
    Abstract:

    Abstract This study determined the local equivalence ratio of a CH 4 /air mixture in a laminar premixed flame using spark-induced breakdown spectroscopy (SIBS) with a fiber-coupled intensified charge coupled device (ICCD) spectrometer. Spectrally resolved emission spectra of plasma generated by a spark plug were investigated for their potential to measure local fuel Concentrations in a premixed mixture. The influence of key parameters, such as the camera gate timing and spark energy, on the intensity of radical emission was illustrated. The intensity ratio of CN/NH had a greater sensitivity to the equivalence ratio than did that of CN/OH, and the local equivalence ratio could be obtained with high resolution by measuring the local intensity ratios of CN/NH. Moreover, a spark-plug sensor with an optical fiber was developed for application in spark-ignition engines. The atomic emission intensity during the breakdown and arc phases of spark discharge could be obtained using the fiber-optic spark-plug sensor. The H α /O intensity showed better linearity than the CN/NH intensity ratio in lean mixtures. The results presented here confirm the use of SIBS as a diagnostic tool for spark-ignition engines.

Y. Ikeda - One of the best experts on this subject based on the ideXlab platform.

  • fuel Concentration Measurement of premixed mixture using spark induced breakdown spectroscopy
    Spectrochimica Acta Part B: Atomic Spectroscopy, 2009
    Co-Authors: Nobuyuki Kawahara, Eiji Tomita, S. Takemoto, Y. Ikeda
    Abstract:

    Abstract This study determined the local equivalence ratio of a CH 4 /air mixture in a laminar premixed flame using spark-induced breakdown spectroscopy (SIBS) with a fiber-coupled intensified charge coupled device (ICCD) spectrometer. Spectrally resolved emission spectra of plasma generated by a spark plug were investigated for their potential to measure local fuel Concentrations in a premixed mixture. The influence of key parameters, such as the camera gate timing and spark energy, on the intensity of radical emission was illustrated. The intensity ratio of CN/NH had a greater sensitivity to the equivalence ratio than did that of CN/OH, and the local equivalence ratio could be obtained with high resolution by measuring the local intensity ratios of CN/NH. Moreover, a spark-plug sensor with an optical fiber was developed for application in spark-ignition engines. The atomic emission intensity during the breakdown and arc phases of spark discharge could be obtained using the fiber-optic spark-plug sensor. The H α /O intensity showed better linearity than the CN/NH intensity ratio in lean mixtures. The results presented here confirm the use of SIBS as a diagnostic tool for spark-ignition engines.

Eiji Tomita - One of the best experts on this subject based on the ideXlab platform.

  • Local fuel Concentration Measurement through spark-induced breakdown spectroscopy in a direct-injection hydrogen spark-ignition engine
    International Journal of Hydrogen Energy, 2016
    Co-Authors: Kazi Mostafijur Rahman, Nobuyuki Kawahara, Eiji Tomita, Daichi Matsunaga, Yasuo Takagi, Yuji Mihara
    Abstract:

    Abstract Quantitative Measurements of local fuel Concentrations were conducted in a direct-injection hydrogen spark-ignition research engine using the spark-induced breakdown spectroscopy (SIBS) technique. For SIBS Measurements, a new sensor was developed from a commercially available M12-type spark plug with no major modifications to the electrodes. The new plug sensor showed better durability and required less maintenance when used in a hydrogen research engine. Emission spectra from the plasma generated by the spark plug were collected through an optical fibre housed in the centre electrode of the plug and resolved spectrally for atomic emissions of Hα, O(I), and N(I). The main focus of the present work was to characterise the effects of ambient pressure at ignition timing on spectral line emissions and to improve the accuracy of SIBS Measurements by taking into account the pressure dependency of atomic emissions. A significant effect of the corresponding pressure at ignition timing was observed on spark-induced breakdown spectroscopic Measurements and emission line characteristics. Retarded spark timing (i.e. higher ambient pressure at the ignition site) resulted in lower spectral line intensities as well as weaker background emissions. It is well established that with relatively higher pressure and density of atoms or molecules, the cooling of expanding plasma accelerates, and the collision probability increases, leading to both a weaker broadband continuum and atomic emissions. A “calibration MAP” representing the correlation of air excess ratio (relative air/fuel ratio) with both intensity ratio and pressure at ignition timing was created and subsequently used for quantitative Measurements of local fuel Concentrations for both port injection and direct injection strategies to demonstrate and explore the effects of pressure dependency of atomic emission on the accuracy of the SIBS Measurements. Local stratification of the fuel mixture in the vicinity of the spark gap location associated with direct injection strategies was confirmed; the coefficient of variation of the local air excess ratio was relatively small for Measurements made using the calibration map. This demonstrated that the Measurement accuracy of local fuel Concentrations through a spark plug sensor can be improved significantly when the pressure dependency of atomic emissions is taken into account.

  • fuel Concentration Measurement of premixed mixture using spark induced breakdown spectroscopy
    Spectrochimica Acta Part B: Atomic Spectroscopy, 2009
    Co-Authors: Nobuyuki Kawahara, Eiji Tomita, S. Takemoto, Y. Ikeda
    Abstract:

    Abstract This study determined the local equivalence ratio of a CH 4 /air mixture in a laminar premixed flame using spark-induced breakdown spectroscopy (SIBS) with a fiber-coupled intensified charge coupled device (ICCD) spectrometer. Spectrally resolved emission spectra of plasma generated by a spark plug were investigated for their potential to measure local fuel Concentrations in a premixed mixture. The influence of key parameters, such as the camera gate timing and spark energy, on the intensity of radical emission was illustrated. The intensity ratio of CN/NH had a greater sensitivity to the equivalence ratio than did that of CN/OH, and the local equivalence ratio could be obtained with high resolution by measuring the local intensity ratios of CN/NH. Moreover, a spark-plug sensor with an optical fiber was developed for application in spark-ignition engines. The atomic emission intensity during the breakdown and arc phases of spark discharge could be obtained using the fiber-optic spark-plug sensor. The H α /O intensity showed better linearity than the CN/NH intensity ratio in lean mixtures. The results presented here confirm the use of SIBS as a diagnostic tool for spark-ignition engines.

Yuji Mihara - One of the best experts on this subject based on the ideXlab platform.

  • Local fuel Concentration Measurement through spark-induced breakdown spectroscopy in a direct-injection hydrogen spark-ignition engine
    International Journal of Hydrogen Energy, 2016
    Co-Authors: Kazi Mostafijur Rahman, Nobuyuki Kawahara, Eiji Tomita, Daichi Matsunaga, Yasuo Takagi, Yuji Mihara
    Abstract:

    Abstract Quantitative Measurements of local fuel Concentrations were conducted in a direct-injection hydrogen spark-ignition research engine using the spark-induced breakdown spectroscopy (SIBS) technique. For SIBS Measurements, a new sensor was developed from a commercially available M12-type spark plug with no major modifications to the electrodes. The new plug sensor showed better durability and required less maintenance when used in a hydrogen research engine. Emission spectra from the plasma generated by the spark plug were collected through an optical fibre housed in the centre electrode of the plug and resolved spectrally for atomic emissions of Hα, O(I), and N(I). The main focus of the present work was to characterise the effects of ambient pressure at ignition timing on spectral line emissions and to improve the accuracy of SIBS Measurements by taking into account the pressure dependency of atomic emissions. A significant effect of the corresponding pressure at ignition timing was observed on spark-induced breakdown spectroscopic Measurements and emission line characteristics. Retarded spark timing (i.e. higher ambient pressure at the ignition site) resulted in lower spectral line intensities as well as weaker background emissions. It is well established that with relatively higher pressure and density of atoms or molecules, the cooling of expanding plasma accelerates, and the collision probability increases, leading to both a weaker broadband continuum and atomic emissions. A “calibration MAP” representing the correlation of air excess ratio (relative air/fuel ratio) with both intensity ratio and pressure at ignition timing was created and subsequently used for quantitative Measurements of local fuel Concentrations for both port injection and direct injection strategies to demonstrate and explore the effects of pressure dependency of atomic emission on the accuracy of the SIBS Measurements. Local stratification of the fuel mixture in the vicinity of the spark gap location associated with direct injection strategies was confirmed; the coefficient of variation of the local air excess ratio was relatively small for Measurements made using the calibration map. This demonstrated that the Measurement accuracy of local fuel Concentrations through a spark plug sensor can be improved significantly when the pressure dependency of atomic emissions is taken into account.

Xu Guang Huang - One of the best experts on this subject based on the ideXlab platform.

  • a quasidistributed fiber optic sensor for solute Concentration Measurement based on fresnel reflection
    Applied Physics Letters, 2007
    Co-Authors: Xu Guang Huang
    Abstract:

    A quasidistributed fiber sensor for solute Concentration Measurement based on Fresnel reflection from fiber tips and the interrogation of an arrayed waveguide grating is presented. Thin-film filters are utilized to achieve the possibility of wavelength-division-multiplexing distributed sensing. The experimental results can be fitted to a linear equation very well, with a value of R2 larger than 0.993. The quasidistributed sensor exhibits a capability for real-time, remote Measurement of Concentrations with high precision, and offers a solid structure, low cost, and easy implementation.