Flash Boiling Effects on the Development of Gasoline Direct-Injection Engine Sprays

Schmitz, Ingo; Ipp, Wolfgang; Leipertz, Alfred

doi:10.4271/2002-01-2661

Cited by 47 publications

(14 citation statements)

References 22 publications

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“…The cylinder pressure drop created in the intake stroke with late IVO timings also has a direct impact on the fuel spray evaporation. With the decrease in cylinder pressure, the potential for flash-boiling of the more volatile fraction of the fuel increases, thereby improving the spray breakup and aiding the spray evaporation and the mixture formation process [15,16]. species Isopentane (4.4 % vol , Psat = 0.91 bar), N-Pentane (1.4 % vol , Psat = 0.68 bar) and Cyclopentane (4.3 % vol , Psat = 0.42 bar) as together they represent 10% of the fuel content and their saturation pressures at ambient temperature are in the range achievable by the late IVO setting.…”

Section: Crank-start With Late Intake Valve Opening/closingmentioning

confidence: 99%

Reduction of Cold-Start Emissions through Valve Timing in a GDI Engine

Rodriguez

Cheng

2016

SAE Int. J. Engines

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This work examines the effect of valve timing during cold crank-start and cold fast-idle (1200 rpm, 2 bar NIMEP) on the emissions of hydrocarbons (HC) and particulate mass and number (PM/PN). Four different cam-phaser configurations are studied in detail: 1. Baseline stock valve timing. 2. Late intake opening/closing. 3. Early exhaust opening/closing. 4. Late intake phasing combined with early exhaust phasing. Delaying the intake valve opening improves the mixture formation process and results in more than 25% reduction of the HC and of the PM/PN emissions during cold crank-start. Early exhaust valve phasing results in a deterioration of the HC and PM/PN emissions performance during cold crank-start. Nevertheless, early exhaust valve phasing slightly improves the HC emissions and substantially reduces the particulate emissions at cold fast-idle. The combined strategy consisting of late intake and early exhaust phasing shows a considerable reduction in both the cold crank-start HC and PM/PN emissions of 30%. In fast idle, the HC and PM emissions respond differently to the different valve timing strategy. The combined late IVO and early EVC configuration with moderate combustion phasing retard gives the best HC and PM emissions and reasonable engine stability.

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Section: Crank-start With Late Intake Valve Opening/closingmentioning

confidence: 99%

Reduction of Cold-Start Emissions through Valve Timing in a GDI Engine

Rodriguez

Cheng

2016

SAE Int. J. Engines

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“…Since then, a number of studies have been performed on flash-boiling atomization phenomena which can be divided into two aspects, one focused on observation of the atomization characteristics of flash-boiling spray outside real DI injectors [4][5][6][7], however, characteristics of superheated flow inside the nozzle cannot be observed. The other one focused on two-phase flow characteristics [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Correlation analysis of superheated liquid jet breakup to bubble formation in a transparent slit nozzle

Zhang

2015

Experimental Thermal and Fluid Science

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“…The flash-boiling spray was then applied to improve combustion and reduce emissions in a diesel engine [11] and was found quite effective for direct injection engines because it enhanced atomization and increased spray angle for rapid fuel-air mixing [12]. Later, optical diagnostic techniques were applied and spray structure were systematically investigated using single/multi-component fuel [13,14] and at various superheated conditions [15][16][17][18] outside the real DI injectors. According to above studies, the structure of flash-boiling spray is totally different and the atomization behavior is much better compared with non-flash-boiling spray when superheat degree (SD) beyond a certain limit at approximately 30°C.…”

Section: Introductionmentioning

confidence: 99%