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

Kim, J. N.; Kim, Ho Young; Yoon, Sunghyun; D., S.

doi:10.1007/s12239-008-0077-7

Cited by 23 publications

(13 citation statements)

References 15 publications

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“…The swirl is highest at the beginning of the intake stroke and slowly reduces to a minimum at BDC. This is similar to the trend found by Kim et al (2008).…”

Section: Resultssupporting

confidence: 92%

“…To determine the swirl parameter, Equation (5) is used in the software computation (Mattarelli 2004, Kim et al 2008;…”

Section: Turbulence and Swirl Modelmentioning

confidence: 99%

“…The other two methods are more difficult to modify in an existing engine. A low-cost method of modifying swirl is to use dissimilar intake valve lift profiles (Kim et al 2008). Although few publications exist on the subject, dissimilar valve profiles have been used in some commercial vehicles to induce more swirl motion.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

Ramasamy

Soon

Briggs

et al. 2013

Journal of the Chinese Institute of Engineers

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Bi-fuel conversions are a common alternative fuelling option for mono-fuel gasoline SI vehicles because of the minor vehicle modifications required. In Malaysia, most bi-fuel vehicles are fuelled with compressed natural gas (CNG) and gasoline. However, CNG flame speed is lower than gasoline reducing the power and range of the vehicle when operating on CNG. This situation can be improved by increasing the flame speed via higher swirl generation. A computational fluid dynamics model is used to analyse swirl generated by dissimilar valve lift (DVL) profiles on the intake valve. A three-dimensional engine simulation shows differences in swirl motion and turbulence between the original symmetric valve lift profile and the DVL. The higher swirl number reduces the turbulence kinetic energy level slightly. The best case profile is selected for further experimental testing.

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“…The swirl is highest at the beginning of the intake stroke and slowly reduces to a minimum at BDC. This is similar to the trend found by Kim et al (2008).…”

Section: Resultssupporting

confidence: 92%

“…To determine the swirl parameter, Equation (5) is used in the software computation (Mattarelli 2004, Kim et al 2008;…”

Section: Turbulence and Swirl Modelmentioning

confidence: 99%

See 1 more Smart Citation

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

Ramasamy

Soon

Briggs

et al. 2013

Journal of the Chinese Institute of Engineers

View full text Add to dashboard Cite

show abstract

“…The quantitative parameter flow uniformity index (UI) has been widely used in the automotive industry to evaluate the mixing distribution inside the mixer, catalyst inlet, and engine. UI can be expressed as follows [70][71][72]:…”

Section: Evaluation Of Flow Uniformitymentioning

confidence: 99%

New Design of a CNG-H2-AIR Mixer for Internal Combustion Engines: An Experimental and Numerical Study

et al. 2017

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Several studies have aimed to convert diesel engines to dual-or tri-fuel engines to improve their fuel economy and reduce the emissions from diesel engine, however, most of these studies do not consider enhancing the homogeneity of fuel mixtures inside the engine and accurately controlling the air fuel ratio. In this study, a new air-fuel mixer was designed, manufactured and tested. The proposed air-gaseous fuel mixer design was conceived to be suitable for mixing air with compressed natural gas (CNG) and a blend of hydrogen and compressed natural gas (HCNG) that gives homogenous mixtures with high uniformity index and also to be easily connected with an Electronic Control Unit (ECU) for controlling accurately the air-gaseous fuel ratio for different engine speeds. For optimizing the homogeneity inside the new mixer, fourteen different mixer models were created to investigate the effects of diameter, location, and the number of holes inside the mixer on the homogeneity and distribution of the mixtures. Computational fluid dynamics analysis software was used to check the flow behavior, distribution and homogeneity of mixtures inside the new mixer models. The simulation results revealed that the best uniformity index (UI) values are obtained in model 7 where the UI values are 0.939 and 0.937, respectively, for an air fuel ratio for a blend of hydrogen and compressed natural gas (AFRHCNG) = 51.31 and the air fuel ratio for compressed natural gas (AFRCNG) = 34.15. According to the numerical and experimental results for the new mixer (model 7) under different engine speeds (1000-4000) and air-CNG ratio of 34.15, a meaningful agreement is reached between the experimental and numerical values for AFRCNG (coefficient of determination (R 2 ) = 0.96 and coefficient of variation (CoV) = 0.001494).

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“…For a quantitative comparison of the tumble flow for different piston designs, the tumble angular velocity ω tx (Mattarelli, Borghi, Balestrazzi, & Fontanesi, 2004) and the tumble ratio NT x (J. N. Kim, Kim, Yoon, & Sa, 2008) are used as the measure of the tumble intensities under different operating conditions. The tumble angular velocity is defined as…”

Section: Effect Of the Piston Shape On The Tumble And Tke Valuesmentioning

confidence: 99%

Effect of the piston top contour on the tumble flow and combustion features of a GDI engine with a CMCV: a CFD study

Yin

Zhang

Sun

et al. 2016

Engineering Applications of Computational Fluid Mechanics

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In spite of much progress in the development of gasoline direct injection (GDI) engines, choosing an appropriate piston top contour to obtain desirable combustion efficiency is still an arduous process for engineers. This study investigates the combined effects of piston bowl geometry and a charge motion control valve (CMCV) on tumble flow and combustion features in GDI engines. Based on the model validation, the processes of intake, spray, mixture formation and combustion at different engine speeds are simulated and analyzed for different piston shapes for the two cases of opening and closing the CMCV. The results show that the bowl on the top of piston is beneficial for the formation and development of tumble flow. The flat top piston with the CMCV closed is able to achieve acceptable combustion pressure. However, with the increase of engine speed and load, the advantages of the flat top pistons gradually disappear; the dual offset bowl piston has a minimum tumble ratio and turbulence kinetic energy (TKE) at the end of the compression stroke because of the projection in the middle of the piston top surface which leads to a lower pressure rise rate and a reduced flame propagation speed at high load. The closed CMCV contributes to a faster evaporation rate and a more uniform mixture at lower speeds. It is not recommended for use at high speeds due to lower intake air mass and reduced combustion pressure. The research provides an effective way for engineers to choose an appropriate piston top contour combined with a CMCV to obtain desirable combustion efficiency. ARTICLE HISTORY

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

Cited by 23 publications

References 15 publications

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

Variation Of Airflow Pattern Through Dissimilar Valve Lift In A Spark Ignition Engine

New Design of a CNG-H2-AIR Mixer for Internal Combustion Engines: An Experimental and Numerical Study

Effect of the piston top contour on the tumble flow and combustion features of a GDI engine with a CMCV: a CFD study

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