Investigation into the Effect of Injection Timing on Stoichiometric and Lean CAI Operations in a 4-Stroke GDI Engine

Cao, Li; Zhao, Hua; Jiang, Xi; Kalian, Navin

doi:10.4271/2006-01-0417

Cited by 19 publications

(10 citation statements)

References 18 publications

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“…Their parametric studies showed that the peak pressure and temperature toward the end of compression stroke was decreased when the EVC timing was retarded, a behavior which may pose a danger to the engine auto-ignition due to low temperature of mixture gases. Generally, for temperatures less than 1000 K, the fuelair mixture cannot easily be auto-ignited (Cao et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine

Kim

Yoon

et al. 2008

Int.J Automot. Technol.

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A fully three-dimensional model was used to investigate the optimal value for intake valve lift in a CAI engine. Uniform mixing in the engine is a key parameter that affects the auto-ignition reliability and thermal efficiency. The method of intake of the air supply often determines the uniformity (or quality) of the fuel-air mixture. In this paper, four strategies were applied for controlling the swirl intensity of intake air. The variation of the intake valve lift induces different swirling and tumbling intensities. Both experimental data and 1D WAVE software (Ricardo, Co.) were coupled with the 3D model to provide pressure and temperature boundary conditions. The initial condition of the EGR mass fraction was also provided by the 1D model. The benchmark scenario (Case 1) was considered as a valve lift with 2 mm for all intake valves. We found that an intake valve lift of 6 mm with the other intake valve closed (i.e., Case 5) yielded the largest swirling (helical motion in the axial direction) and tumbling, which in turn rendered optimal fuel-gas mixing. We also found that fuel distribution affected the auto-ignition sites (or spot). The better the mixing, the greater the gas temperature and combustion efficiency achieved, as seen in Case 5. The NOx level, however, was increased due to the gas temperature. The optimal operating condition is selected from the viewpoints of environmental protection and combustion efficiency.

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Section: Introductionmentioning

confidence: 99%

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine

Kim

Yoon

et al. 2008

Int.J Automot. Technol.

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“…In order to understand better the underlying mechanisms, detailed analysis has been carried out on the physical and chemical processes taking place within the cylinder by means of 3-dimensional full cycle engine simulation [14]. The simulation programme is based on the KIVA3v with improvements in turbulence, the gas/wall heat transfer, spray atomisation, ignition and combustion and it takes into account the gas exchange processes that are crucial to the residual gas trapping method.…”

Section: Early Injections During the Negative Valve Overlap Periodmentioning

confidence: 99%

Four-stroke CAI engines with residual gas trapping

Zhao

2007

HCCI and CAI Engines for the Automotive Industry

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“…As a result, early NVO injection advances the start of combustion by a couple of degrees when compared to mixture preparation outside of the cylinder under the same thermal conditions [7,8]. However, the majority of researchers recognize thermal NVO processes as dominant in combustion development [9,10]. The amount of the in-cylinder gas and its thermodynamic conditions at intake valve opening event determines the amount of aspirated air and the in-cylinder temperature at the start of compression.…”

Section: Introductionmentioning

confidence: 99%

Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

Hunicz

Medina

Litak

et al. 2015

Entropy

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Abstract:In this study we summarize and analyze experimental observations of cyclic variability in homogeneous charge compression ignition (HCCI) combustion in a single-cylinder gasoline engine. The engine was configured with negative valve overlap (NVO) to trap residual gases from prior cycles and thus enable auto-ignition in successive cycles. Correlations were developed between different fuel injection strategies and cycle average combustion and work output profiles. Hypothesized physical mechanisms based on these correlations were then compared with trends in cycle-by-cycle predictability as revealed by sample entropy. The results of these comparisons help to clarify how fuel injection strategy can interact with prior cycle effects to affect combustion stability and so contribute to design control methods for HCCI engines.

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Investigation into the Effect of Injection Timing on Stoichiometric and Lean CAI Operations in a 4-Stroke GDI Engine

Cited by 19 publications

References 18 publications

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine

Four-stroke CAI engines with residual gas trapping

Effects of Direct Fuel Injection Strategies on Cycle-by-Cycle Variability in a Gasoline Homogeneous Charge Compression Ignition Engine: Sample Entropy Analysis

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