In-cylinder Combustion Visualization of a Direct-injection Spark-ignition Engine with Different Operating Conditions and Fuels

Mittal, Mayank; Schock, Harold; Zhu, Guoming

doi:10.4271/2012-01-1644

Cited by 4 publications

(3 citation statements)

References 19 publications

(23 reference statements)

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“…Based on the HRR curves shown, it can be concluded that the shape of HRR in DF combustion is a function of TDC temperature, operating load conditions and the premixed gas-to-air equivalence ratio. Additionally, the HRR curves follow SI combustion behavior more closely [26], suggesting that the premixed turbulent flame front propagation is a dominant mode of combustion.…”

Section: Effect Of φCh4 and Intake Air Temperature (Ttdc)mentioning

confidence: 76%

An Optical Characterization of Dual-Fuel Combustion in a Heavy-Duty Diesel Engine

Ahmad¹,

Aryal²,

Ranta³

et al. 2018

SAE Technical Paper Series

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Dual fuel (DF) combustion technology as a feasible approach controlling engine-out emissions facilitates the concept of fuel flexibility in diesel engines. The abundance of natural gas (90-95% methane) and its relatively low-price and the clean-burning characteristic has attracted the interest of engine manufacturers. Moreover, with the low C/H ratio and very low sooting tendency of methane combined with high engine efficiency, makes it a viable primary fuel for diesel engines. However, the fundamental knowledge on in-cylinder combustion phenomena still remains limited and needs to be studied for further advances in the research on DF technology. The objective of this study is to investigate the ignition delay with the effect of, 1) methane equivalence ratio, 2) intake air temperature and 3) pilot ratio on the diesel-methane DFcombustion. Combustion phenomenon was visualized in a single cylinder heavy-duty diesel engine modified for DF operations with an optical access. The high-speed natural luminosity (NL) imaging technique was employed to record the temporally resolved incylinder combustion event at an operating load of approx. 10 bar IMEP at 1400 rpm. The results show that flame propagation becomes stable and sustained with an increase in either of the methane equivalence ratio, intake air temperature, or diesel amount. However, the sensitivity of each effect on the flame propagation and ignition delay was observed to be different. The effect of these parameters on DF combustion has been characterized with the help of NL images and corresponding cylinder pressure and net heat-release rate (HRR) data. The study also presents a detailed discussion on the analyzed ignition delay trends.

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Section: Effect Of φCh4 and Intake Air Temperature (Ttdc)mentioning

confidence: 76%

An Optical Characterization of Dual-Fuel Combustion in a Heavy-Duty Diesel Engine

Ahmad¹,

Aryal²,

Ranta³

et al. 2018

SAE Technical Paper Series

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“…Of these blends, E20 achieved the most optimal specific fuel consumption (SFC). Studies have also shown that ethanol increases flame front speed and early flame development [20,31,32,33]. Improvements in combustion dynamic may increase torque at high rpm.…”

mentioning

confidence: 98%

Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

Burke¹,

Rhoads²,

Ratcliff³

et al. 2018

SAE Technical Paper Series

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A relationship has been observed between increasing ethanol content in gasoline and increased particulate matter (PM) emissions from direct injection spark ignition (DISI) vehicles. The fundamental cause of this observation is not well understood. One potential explanation is that increased evaporative cooling as a result of ethanol's high HOV may slow evaporation and prevent sufficient reactant mixing resulting in the combustion of localized fuel rich regions within the cylinder. In addition, it is well known that ethanol when blended in gasoline forms positive azeotropes which can alter the liquid/vapor composition during the vaporization process. In fact, it was shown recently through a numerical study that these interactions can retain the aromatic species within the liquid phase impeding the in-cylinder mixing of these compounds, which would accentuate PM formation upon combustion. To better understand the role of the azeotrope interactions on the vapor/liquid composition evolution of the fuel, distillations were performed using the Advanced Distillation Curve apparatus on carefully selected samples consisting of gasoline blended with ethanol and heavy aromatic and oxygenated compounds with varying vapor pressures, including cumene, p-cymene, 4-tertbutyl toluene, anisole, and 4-methyl anisole. Samples collected during the distillation indicate an enrichment of the heavy aromatic or oxygenated additive with an increase in initial ethanol concentration from E0 to E30. A recently developed distillation and droplet evaporation model is used to explore the influence of dilution effects versus azeotrope interactions on the aromatic species enrichment. The results suggest that HOV-cooling effects as well as aromatic species enrichment behaviors should be considered in future development of predictive indices to forecast the PM potential of fuels containing oxygenated compounds with comparatively high HOV.NREL/CP-5400-71336. Posted with permission.

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“…Furthermore, this piston top allows the laser to illuminate the flow inside the cylinder in tumble flow studies [23,24]. Also, it is used to allow the combustion flames to be captured with a high-speed camera in the case of firing operations [38,39]. In optical engine design, the piston top is a necessary component.…”

Section: Application Of the Coupled Finite Element Analysis Methodolo...mentioning

confidence: 99%

An Analysis of Mechanical and Thermal Stresses, Temperature and Displacement within the Transparent Cylinder and Piston Top of a Small Direct-Injection Spark-Ignition Optical Engine

Velugula,

Thiruvallur loganathan,

Varadhaiyengar

et al. 2023

Energies

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Two- and three-wheeled vehicles account for a significant portion of the automobile market in several countries worldwide. In order to advance the capabilities of these vehicles, the integration of direct-injection (DI) technology is essential, given its potential benefits such as high thermal efficiency and low engine-out emissions. Direct injection in small-bore engines, however, further complicates the challenges involved (of DI technology) like fuel impingement and mixture inhomogeneity inside the engine cylinder, driving the need for an in-depth exploration of in-cylinder processes. Consequently, the necessity arises to develop a small-bore direct-injection spark-ignition (DISI) optical engine that incorporates a transparent cylinder and piston top. In this scenario, these transparent components are required to endure a combination of intricate loads and boundary conditions, hence the potential to result in failures. This work aims to assess numerically the effects of these loads and boundary conditions on the transparent components and optimize their thicknesses. For this purpose, a computer-aided design model of a small-bore DISI optical engine (displacement volume of 200 cm3) is developed. The mechanical and thermal loads are extracted from the experimental data and validated computational fluid dynamics model of the same engine configuration. A coupled temperature-displacement finite element analysis methodology is developed in ABAQUS/CAE, and simulations are performed under both steady and transient conditions. Temperature and combined stress distributions within the transparent cylinder and piston top are obtained and analyzed to find their optimum thicknesses. Knowing thermal gradients, combined stresses and displacements under actual conditions helped design the small optical engine with an improved factor of safety.

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In-cylinder Combustion Visualization of a Direct-injection Spark-ignition Engine with Different Operating Conditions and Fuels

Cited by 4 publications

References 19 publications

An Optical Characterization of Dual-Fuel Combustion in a Heavy-Duty Diesel Engine

An Optical Characterization of Dual-Fuel Combustion in a Heavy-Duty Diesel Engine

Measured and Predicted Vapor Liquid Equilibrium of Ethanol-Gasoline Fuels with Insight on the Influence of Azeotrope Interactions on Aromatic Species Enrichment and Particulate Matter Formation in Spark Ignition Engines

An Analysis of Mechanical and Thermal Stresses, Temperature and Displacement within the Transparent Cylinder and Piston Top of a Small Direct-Injection Spark-Ignition Optical Engine

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