Mixture Formation of Fuel Injection Systems in Gasoline Engines

Nogi, Toshiharu; Ohyama, Yoshishige; Yamauchi, Teruo; Kuroiwa, Hiroshi

doi:10.4271/880558

Cited by 61 publications

(8 citation statements)

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“…As shown in Figs. 9-12, around 10 CAD ATDC, the flame front interacted with the fuel deposits on the intake valves and diffusion-controlled flames with high luminosity were observed [6,19]. As shown in Fig.…”

Section: Resultsmentioning

confidence: 92%

“…After reaching the combustion chamber, the fuel droplets stuck on the piston surfaces created fuel-rich zones that developed dynamically under the effect of the gas flow influencing the composition of the mixture and hence the combustion process. Analogous effects involved the fuel droplets stripped by the fuel film deposited onto the port wall or the back side of the inlet valve [6][7][8][18][19][20]. To better understand the influences of these phenomena on the combustion process, cycle resolved imaging was performed.…”

Section: Resultsmentioning

confidence: 99%

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Optical investigation of the fuel injector influence in a PFI spark ignition engine for two-wheel vehicles

2012

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This paper describes the results obtained in a port fuel injection spark-ignition (PFI SI) engine by optical diagnostics during the fuel injection and the combustion process. A research optical engine was equipped with the fuel injection system, the head and the exhaust device of a commercial 250 cc engine for scooters and small motorcycles. Two injectors were tested: standard 3-hole injector that equipped the real reference engine and a 12-hole injector. The intake manifold was modified to allow the visualization of the fuel injection using an endoscopic system coupled with CCD camera. Size and number of the fuel droplets were evaluated through an image processing procedure. The cycle resolved visualization and chemiluminescence allowed to follow the combustion process from the spark ignition to the exhaust phase. All the optical data were correlated with engine parameters and exhaust emissions. The effect of the fuel injector type on deposits formed by fuel accumulation and dripping on the intake valves steams and seats was investigated. In particular, the evolution of diffusion-controlled flames due to the fuel deposits burning was analyzed. These flames were principally located near the intake valves, and they persisted well after the normal combustion event. The consequences were the formation and emission of soot and unburned hydrocarbons. The multi-hole injector helped reducing wall wetting and deposit formation so that the emission characteristic can be improved. The use of 12-hole injector allowed a more homogeneous distribution for a lower time of fuel droplets in the intake manifold than the 3-hole injector. This study also investigated the detailed physical/chemical phenomena to figure out reasons for the improvement using optical measurements.

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Section: Resultsmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Optical investigation of the fuel injector influence in a PFI spark ignition engine for two-wheel vehicles

2012

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“…Even though these images are 50 cycles averaged, it is clear that fuel stratification near the spark plug is achieved in the case of OVI, which might contribute to the extension of the lean limit. According to Nogi et al (8) , strong air flow distorts the spray pattern in the case of OVI and might cause mixture maldistribution in a gasoline-fueled engine. However, this is not true in the case of an LPLI engine.…”

Section: Resultsmentioning

confidence: 99%

“…This is a noticeable difference of LPG-fueled engines when com- pared with gasoline engines. Generally, for gasoline engines, the amount of HC emission increases due to fuel wetting and mal-distribution of mixture (8) . However, LPG fuel has high volatility and has negligible effect of fuel wetting on the valve and cylinder wall, which leads to HC emissions being maintained at the same level.…”

Section: Resultsmentioning

confidence: 99%

Effects of Injection Timing on Mixture Distribution in a Liquid-Phase LPG Injection Engine for a Heavy-Duty Vehicle

Lee

Kim

et al. 2004

JSME international journal. Ser. B, Fluids and thermal engineer

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Effects of injection timing on mixture distribution were investigated in a liquid phase LPG injection engine for a heavy-duty vehicle. An optically accessible engine was made for planar laser induced fluorescence and flame imaging. Mixture distributions around the spark plug were quantified and compared for open and closed valve injection. Two-dimensional flame images were taken to investigate the effect of mixture stratification on flame propagation. In addition, the overall engine performance and emissions were compared for the injection timings at a selected condition. Unlike the case of closed valve injection, where a nearly homogeneous mixture is formed near the spark plug and the flame moves with swirl, in the case of open valve injection, a cloud of richer mixture than overall excess air ratio is formed near the spark plug and the flame moves in the direction of the rich mixture, which extends the limit of lean burn operation.

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“…The unstable waves generated on a liquid surface subject to a high velocity gas (in the relative sense) are very important in atomization problems such as the atomization of cylindrical or annular coaxial cylindrical jets injected into engines (Lin and Chen [16]), and the atomization of wall-attached liquid films as can be found in the intake wall of gasoline engines with multipoint injection systems (Nogi et al [30]). The atomization of liquid by gas flow has been extensively studied in the past for cylindrical jets (Sterling and Sleicher [38], Reitz and Bracco [33], Lin and Lian [18], Li [14], Leroux, Dumouchel and Ledoux [8], Lin and Chen [16], etc.…”

Section: Introductionmentioning

confidence: 99%

Most unstable waves of a stagnant planar liquid film blown by a high speed viscous gas with a Blasius velocity profile

2001

Acta Mechanica

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The linear most unstable waves generated on the surface of a stagnant planar liquid (gasoline) film with infinite thickness, blown by a high speed viscous gas (air) with a Blasius velocity profile, are computed and analyzed. The free-stream velocity of the gas ranges from 30 m/s to 50 m/s, which is typical of high speed atomization problems. The Reynolds number based on the local thickness of the boundarylayer lies between 200 and 2 500. The numerical computation shows that the dimensional wavelength of the most unstable wave is a power function of the boundary-layer thickness (or Reynolds number) with a power close to 3/4, while the growth rate is inversely proportional to the boundary-layer thickness. When reducing the boundary-layer thickness, the viscous results approach the inviscid results. This result shows that, under the present parameter range, the gas viscosity would have a secondary role on the atomization speed and important influence on the droplet size.

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Mixture Formation of Fuel Injection Systems in Gasoline Engines

Cited by 61 publications

References 0 publications

Optical investigation of the fuel injector influence in a PFI spark ignition engine for two-wheel vehicles

Optical investigation of the fuel injector influence in a PFI spark ignition engine for two-wheel vehicles

Effects of Injection Timing on Mixture Distribution in a Liquid-Phase LPG Injection Engine for a Heavy-Duty Vehicle

Most unstable waves of a stagnant planar liquid film blown by a high speed viscous gas with a Blasius velocity profile

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