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Shouji, Kiyotaka
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A Study of Combustion Technology for a High Compression Ratio Engine: The Influence of Combustion Chamber Wall Temperature on Knocking

SAE International Journal of Engines

Nissan Motor Co., Ltd.-Yoshihiro Imaoka, Kiyotaka Shouji, Takao Inoue, Toru Noda
  • Journal Article
  • 2016-01-0703
Published 2016-04-05 by SAE International in United States
Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio is an example of a technology for improving the thermal efficiency of gasoline engines. A significant issue of a high compression ratio engine for improving fuel economy and low-end torque is prevention of knocking under a low engine speed. Knocking is caused by autoignition of the air-fuel mixture in the cylinder and seems to be largely affected by heat transfer from the intake port and combustion chamber walls. In this study, the influence of heat transfer from the walls of each part was analyzed by the following three approaches using computational fluid dynamics (CFD) and experiments conducted with a multi-cooling engine system. First, the temperature rise of the air-fuel mixture by heat transfer from each part was analyzed. Heat transfer from the intake port and cylinder head was found to be higher than that from other parts due to the high flow velocity during the intake stroke. Therefore,…
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A Study of a Multistage Injection Mechanism for Improving the Combustion of Direct-Injection Gasoline Engines

SAE International Journal of Engines

Nissan Motor Co., Ltd.-Yoshihiro Imaoka, Kiyotaka Shouji, Takao Inoue, Toru Noda
  • Journal Article
  • 2015-01-0883
Published 2015-04-14 by SAE International in United States
Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio for improving thermal efficiency and downsizing the engine based on fuel-efficient operating conditions are good examples of technologies for enhancing gasoline engine fuel economy. A direct-injection system is adopted for most of these engines. Direct injection can prevent knocking by lowering the in-cylinder temperature through fuel evaporation in the cylinder. Therefore, direct injection is highly compatible with downsized engines that frequently operate under severe supercharging conditions for improving fuel economy as well as with high compression ratio engines for which susceptibility to knocking is a disadvantage. On the other hand, direct-injection engines have certain issues such as the need to reduce particulate matter (PM) emissions, and technical measures must be developed for that purpose. Multistage injection is one method of improving direct-injection engines and has both advantages and disadvantages. One benefit of multistage injection is lower PM emissions caused by liquid fuel impinging on the cylinder wall. That…
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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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