An Experimental Study on Fuel Behavior During the Cold Start Period of a Direct Injection Spark Ignition Engine

Koga, Nobuhiko; Miyashita, Shigeki; Takeda, Keiso; Imatake, Nobuo

doi:10.4271/2001-01-0969

Cited by 11 publications

(6 citation statements)

References 2 publications

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“…The DISI engine hydrocarbon (HC) emissions have been a challenge [3,[9][10][11]. The cold start emissions, which contribute predominantly to the total trip emissions because the catalyst has not reached light-off temperature, are especially problematic.…”

Section: Introductionmentioning

confidence: 99%

“…1. The high-pressure fuel pump cannot maintain the required fuel pressure in the cranking process [9,11]; atomization and fuel evaporation are then poor. 2.…”

Section: Introductionmentioning

confidence: 99%

“…2. The gas temperature is not high enough for significant droplet evaporation, so that a substantial amount of liquid fuel lands on the cylinder walls [9,10]. It is noted that, although the metered fuel required for a stable start-up process is less for a DISI than for a port fuel injection (PFI) engine, the amount of fuel retained in the cylinder and the engine-out HC emissions are significantly higher, even when an independently pressurized fuel injection system is used [9].…”

Section: Introductionmentioning

confidence: 99%

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Organic gas emissions from a stoichiometric direct injection spark ignition engine operating on ethanol/gasoline blends

Kar

Tharp

Radovanovic

et al. 2010

International Journal of Engine Research

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Section: Introductionmentioning

confidence: 99%

“…1. The high-pressure fuel pump cannot maintain the required fuel pressure in the cranking process [9,11]; atomization and fuel evaporation are then poor. 2.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Organic gas emissions from a stoichiometric direct injection spark ignition engine operating on ethanol/gasoline blends

Kar

Tharp

Radovanovic

et al. 2010

International Journal of Engine Research

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show abstract

“…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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“…NOx emission was improved in the first 32 s under the cold start condition, but slight deteriorated afterward due to an overall higher combustion temperature induced by heated fuel injection. 28 Koga et al 29 also heated up the fuel injector and delayed the opening time of the intake valve (to reduce the ambient pressure) to promote fuel flash boiling and compared the two approaching in reaching flash boiling atomization. The results showed that both approaches had suppressed the THC emission, while the performance by heating up the fuel was better with a 50% THC emission reduction.…”

Section: Introductionmentioning

confidence: 99%

Combustion Improved by Using Flash Boiling Sprays in an Ethanol-Gasoline Optical Engine under Cold Operating Conditions

Yang¹,

Sun²,

Gu³

et al. 2021

Energy Fuels

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The development of renewable fuels has attracted widespread attention for internal combustion engines. Among the alternative fuels, ethanol has always been the main substitute for gasoline because it can be readily produced from biomass. However, because ethanol has a higher enthalpy of vaporization than gasoline, it is difficult to evaporate under cold operating conditions. This factor will deteriorate engine output power and exhaust pollutant emissions. To solve this issue, visualization research on the flash boiling combustion process in an ethanol-gasoline optical engine was conducted. This work comprehensively evaluated the spray characteristics, flame propagation behaviors, and exhaust emissions of ethanol-gasoline blends. The fuel temperatures of 30°C, 90°C, and 150°C were used to represent three thermodynamic conditions. The results revealed that the flame propagation speed and flame presence probability index monotonically decrease with a higher ethanol addition under the subcooled injection cases (30°C). However, heating the fuel temperature to 150 °C can enhance the evaporation of liquid fuel, which can offset some negative effects from adding ethanol. Thus, consequently, more stable and faster flame formation was achieved by flare flash boiling injection (150°C), which could help promote engine output performance. The net indicated mean effective pressure has been increased from 1.75 to 2.19 bar, an improvement of 25.1%. While the flare flash boiling injection can help reduce PN, THC, and CO emissions, the NOx emission was compromised due to a higher combustion temperature. Finally, this study revealed the flash boiling combustion mechanisms for ethanol-gasoline blends fuels under cold operating conditions.

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An Experimental Study on Fuel Behavior During the Cold Start Period of a Direct Injection Spark Ignition Engine

Cited by 11 publications

References 2 publications

Organic gas emissions from a stoichiometric direct injection spark ignition engine operating on ethanol/gasoline blends

Organic gas emissions from a stoichiometric direct injection spark ignition engine operating on ethanol/gasoline blends

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

Combustion Improved by Using Flash Boiling Sprays in an Ethanol-Gasoline Optical Engine under Cold Operating Conditions

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