Three-Dimensional Computations of the Scavenging Process in an Opposed-Piston Engine

Zhu, Yicheng; Savonen, Craig; Johnson, Norman L.; Amsden, A.A.

doi:10.4271/941899

Cited by 10 publications

(5 citation statements)

References 3 publications

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“…As shown by the calculations [29], there is also a relationship between the scavenging efficiency and the previously mentioned stroke to bore ratio. For the four S/B geometries analyzed there in the range from 1.08 to 2.5, it turns out that the highest parameter value corresponds to almost ideal scavenging conditions, with the efficiency increasing from 0.813 to 0.934.…”

Section: Uniflow Scavengingsupporting

confidence: 52%

The Potential of Wobble Plate Opposed Piston Axial Engines for Increased Efficiency

Mazuro

Makarewicz

2020

Energies

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Recent announcements regarding the phase out of internal combustion engines indicate the need to make major changes in the automotive industry. Bearing in mind this innovation trend, the article proposes a new approach to the engine design. The aim of this paper is to shed a new light on the forgotten concept of axial engines with wobble plate mechanism. One of their most important advantages is the ease of use of the opposed piston layout, which has recently received much attention. Based on several years of research, the features determining the increase in mechanical efficiency, lower heat losses and the best scavenging efficiency were indicated. Thanks to the applied Variable Compression Ratio (VCR), Variable Angle Shift (VAS) and Variable Port Area (VPA) systems, the engine can operate on various fuels in each of the Spark Ignition (SI), Compression Ignition (CI) and Homogeneous Charge Compression Ignition (HCCI)/Controlled Auto Ignition (CAI) modes. In order to quantify the potential of the proposed design, an initial research of the newest PAMAR 4 engine was presented to calculate the torque curve at low rotational speeds. The achieved torque of 500 Nm at 500 rpm is 65% greater than the maximum torque of the OM 651 engine of the same 1.8 L capacity. The findings lead to the conclusion that axial engines are wrongfully overlooked and can significantly improve research on new trends in pollutant elimination.

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Section: Uniflow Scavengingsupporting

confidence: 52%

The Potential of Wobble Plate Opposed Piston Axial Engines for Increased Efficiency

Mazuro

Makarewicz

2020

Energies

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“…Zhu et al performed three-dimensional (3D) computations of the scavenging process in an opposed-piston uniflow scavenged two-stroke engine and found the SE is most sensitive to the B/S ratio. 24 With a small B/S ratio (less than 0.5), the scavenging flow structure is improved considerably, and the scavenging is close to ideal.…”

Section: Introductionmentioning

confidence: 99%

“…Although these studies have revealed some understanding of the effects of B/S ratio on the scavenging process in poppet valve, 22 loop, 9 and cross scavenged engines, 23 and opposite-piston engines, 24 the impacts of B/S ratio on uniflow scavenged two-stroke engines have not been fully analyzed. In this study, 3D computational fluid dynamics (CFD) simulations were performed to evaluate the scavenging process of the proposed BUSDIG engine with different B/S ratios.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the effect of bore/stroke ratio and scavenge port angles on the scavenging process in a two-stroke boosted uniflow scavenged direct injection gasoline engine

Wang

Zhao

2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this study, a two-stroke boosted uniflow scavenged direct injection gasoline (BUSDIG) engine was proposed and researched to achieve aggressive engine downsizing and downspeeding. Compared to loop or cross scavenged twostroke engines, the BUSDIG engine can achieve excellent scavenging performance and be operated with higher boost pressure as well as the absence of air and fuel short-circuiting. As a fundamental engine geometric parameter, the bore/ stroke (B/S) ratio would directly affect the scavenging process in the uniflow scavenged two-stroke engine. Three-dimensional computational fluid dynamics simulations were used to investigate the scavenging process in the BUSDIG engine with different B/S ratios. Four B/S ratios of 0.66, 0.8, 1, and 1.3 were analyzed. The results indicate that a bigger B/S ratio leads to deteriorated swirl flow motion but better delivery ratio, scavenging efficiency, and charging efficiency. In order to fulfil the potential of the BUSDIG engine with different B/S ratios, two key scavenge port angles, i.e. axis inclination angle (AIA) and swirl orientation angle (SOA), were varied from the baseline design (AIA = 90°, SOA = 20°) to study their effects on the scavenging process for each B/S ratio design. Overall, a larger AIA leads to lower swirl ratio (SR) but achieves better scavenge performance, which is crucial for a large B/S ratio design. A small SOA design leads to noticeably lower SR but superior scavenging performances for a small B/S ratio design. An intermediate SOA, e.g. 10 and 20°, is preferred to improve the scavenging for a large B/S ratio design.

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“…A step in this direction was to introduce multi-block hexahedral structures, as employed in the IFP KIVA-MB [3], KIVA-III and [4] FIRE 1 codes, which facilitate fitting of ports and cylinder head and piston recesses, along with other benefits. The Speed [5] code carries this a stage further by allowing general unstructured hexahedral meshes.…”

Section: Flexible Meshesmentioning

confidence: 99%

State of the Art of Multi-Dimensional Modeling of Engine Reacting Flows

Gosman

1999

Oil & Gas Science and Technology - Rev. IFP

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RŽsumŽ Ñ ƒtat de lÕart de la modŽlisation multidimensionnelle pour les Žcoulements rŽactifs dans les moteurs Ñ Cet article dresse un aper•u de lÕŽtat de lÕart et des perspectives de lÕutilisation de la modŽlisation 3D pour lÕanalyse et le dŽveloppement des moteurs. Les aspects abordŽs comprennent lÕacquisition des gŽomŽtries, la gŽnŽration des maillages, les mŽthodologies numŽriques, la modŽlisation mathŽmatique des phŽnom•nes physiques importants, lÕexploitation des calculateurs parall•les et lÕapplication industrielle. Les conclusions principales de cette analyse font appara"tre les points suivants : Ð les mŽthodologies numŽriques et la gŽnŽration des maillages, associŽes au calcul parall•le, permettent maintenant de raccourcir notablement le cycle total de simulation ; Ð la modŽlisation physique a atteint sa maturitŽ dans la plupart des aspects relatifs ˆ la simulation de la combustion en allumage commandŽ ; en revanche, elle reste encore ˆ acquŽrir en ce qui concerne la combustion Diesel et certains aspects des processus reliŽs aux sprays ; Ð globalement, lÕutilisation de la simulation 3D pour la conception des moteurs est en forte augmentation ; Ð les dŽveloppements futurs, dont lÕutilisation de la LES, promettent une amŽlioration croissante des rŽsultats.Mots-clŽs : moteur, combustion, simulation 3D, aper•u. Abstract Ñ State of the Art of Multi-Dimensional Modeling of Engine Reacting Flows

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Three-Dimensional Computations of the Scavenging Process in an Opposed-Piston Engine

Cited by 10 publications

References 3 publications

The Potential of Wobble Plate Opposed Piston Axial Engines for Increased Efficiency

The Potential of Wobble Plate Opposed Piston Axial Engines for Increased Efficiency

Analysis of the effect of bore/stroke ratio and scavenge port angles on the scavenging process in a two-stroke boosted uniflow scavenged direct injection gasoline engine

State of the Art of Multi-Dimensional Modeling of Engine Reacting Flows

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