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Chaya, Tomohiro
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Crank-angle-resolved Measurements of Air-fuel Ratio, Temperature, and Liquid Fuel Droplet Scattering in a Direct-injection Gasoline Engine

Nissan Motor Co., Ltd.-Kevin R. Sholes, Kiyotaka Shouji, Tomohiro Chaya
Stanford University-Jay B. Jeffries, Jason M. Porter, Sung Hyun Pyun, Ronald K. Hanson
Published 2010-10-25 by SAE International in United States
Simultaneous crank-angle-resolved measurements of gasoline vapor concentration, gas temperature, and liquid fuel droplet scattering were made with three-color infrared absorption in a direct-injection spark-ignition engine with premium gasoline. The infrared light was coupled into and out of the cylinder using fiber optics incorporated into a modified spark plug, allowing measurement at a location adjacent to the spark plug electrode. Two mid-infrared (mid-IR) laser wavelengths were simultaneously produced by difference-frequency-generation in periodically poled lithium niobate (PPLN) using one signal and two pump lasers operating in the near-infrared (near-IR). A portion of the near-IR signal laser residual provided a simultaneous third, non-resonant, wavelength for liquid droplet detection. This non-resonant signal was used to subtract the influence of droplet scattering from the resonant mid-IR signals to obtain vapor absorption signals in the presence of droplet extinction.The sensor was applied to a direct-injection engine in both early-injection homogeneous charge and late-injection stratified charge operation. For the early-injection cases, liquid droplets were detected only during a brief period of the intake stroke just after start of injection. Late in the…
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An In-cylinder Laser Absorption Sensor for Crank-angle-resolved Measurements of Gasoline Concentration and Temperature

SAE International Journal of Engines

Nissan Motor Co Ltd-Kevin R. Sholes, Kiyotaka Shouji, Tomohiro Chaya
Stanford Univ.-Jay B. Jeffries, Jason M. Porter, Sung Hung Pyun, Ronald K. Hanson
  • Journal Article
  • 2010-01-2251
Published 2010-10-25 by SAE International in United States
Simultaneous crank-angle-resolved measurements of gasoline concentration and gas temperature were made with two-color mid-infrared (mid-IR) laser absorption in a production spark-ignition engine (Nissan MR20DE, 2.0L, 4 cyl, MPI with premium gasoline). The mid-IR light was coupled into and out of the cylinder using fiber optics incorporated into a modified spark plug. The absorption line-of-sight was a 5.3 mm optical path located closely adjacent to the ignition spark providing spatially resolved absorption. Two sensor wavelengths were selected in the strong bands associated with the carbon-hydrogen (C-H) stretching vibration near 3.4 μm, which have an absorption ratio that is strongly temperature dependent. Fuel concentration and temperature were determined simultaneously from the absorption at these two wavelengths. The two mid-IR laser wavelengths were simultaneously produced by difference-frequency-generation in a periodically poled lithium niobate (PPLN) crystal using one signal and two pump lasers. The pump lasers were modulated at different frequencies allowing frequency demultiplexing of the laser light transmitted though the spark plug probe, providing simultaneous absorption signals at the two mid-IR wavelengths. A model of the absorption cross…
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Analysis of In-Cylinder Unburned Hydrocarbons Using a High-Speed Sampling Valve

Nissan Motor Co., Ltd.-Yoshinobu Hamada, Tomohiro Chaya, Hideki Nomura, Kevin Sholes, Junichi Kawashima
  • Technical Paper
  • 2008-08-0313
Published 2008-10-22 by Society of Automotive Engineers of Japan in Japan
The purpose of this work is to develop a method suitable for evaluating the potential for new combustion concepts to reduce engine-out emissions in a real engine. A new dual sampling valve from Cambustion Ltd. enables gas sampling of the wall quench layer by controlling the purge gas volume from the cylinder.In cold engine conditions in the near wall region, intermediate combustion products such as methane, ethane, ethylene and acetylene are detected while heavier HC components show modest decrease with distance away from the wall, indicating some post-combustion oxidation of unreacted HCs released from the quench layer. However, by comparison with exhaust port measurements it is shown that the majority of oxidation occurs in the bulk cylinder gas away from the walls.