The New BMW Motorrad Boxer Engine with ShiftCam Technology

Kallich, Stefan; Graf, Hubert; Schaller, Karl Viktor; Ritter, Stefan

doi:10.1007/s38313-019-0006-3

Cited by 3 publications

(4 citation statements)

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“…Manufacturers use a "downsized" engine from their line of products and design a larger displacement engine, the increase in size coming from the extended expansion of the Miller cycle. Examples include Opel's Ecotec engines [58], [59], Volkswagen's TSI engines [60], Audi's TFSI [61] and also BMW's boxer engine for motorcycles [62]. The increase in displacement is mainly achieved by increasing the piston stroke.…”

Section: Application Strategymentioning

confidence: 99%

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Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Perceau

Guibert

Guilain

2021

Applied Thermal Engineering

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Section: Application Strategymentioning

confidence: 99%

“…This approach is called "dethrottling". The idea is not new and dates back to the 1980s [64], but advances in variable lift and valve timing systems have democratized its use [62], [65], [66]. The engine can have two camshafts, one for the high loads and one for the low loads.…”

Section: Application Strategymentioning

confidence: 99%

Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Perceau

Guibert

Guilain

2021

Applied Thermal Engineering

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“…L'augmentation de taille vient de la détente prolongée du cycle de Miller. Nous pouvons citer l'exemple des moteur Ecotec de Opel [19], [20], des moteurs TSI de Volkswagen [21], des moteurs TFSI de Audi [22] et également du moteur boxer pour motos de BMW [23]. L'augmentation de la cylindrée s'effectue principalement en augmentant la course du piston.…”

Section: Démarche « Rightsizing »unclassified

Modélisation 0D turbulente d’un moteur essence en vue de sa Millérisation

Perceau¹,

Guibert²,

Guilain³

2020

Entropie

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Les nouvelles restrictions environnementales poussent les constructeurs automobiles à s'intéresser aux cycles à détente prolongée et à laisser de côté le classique cycle de Beau de Rochas. Le cycle de Miller fait partie de cette famille de cycle et peut s'appliquer simplement aux moteurs à allumage commandé en modifiant le diagramme de fermeture des soupapes d'admission. Le moteur effectue une détente plus importante que la phase de compression effective. La millérisation d'un moteur se fait en augmentant la taille de celui-ci et en fermant les soupapes d'admission en avance. L'instant de fermeture est choisi de manière à suivre la même phase de compression effective que le moteur de référence. Cette démarche est connue sous le nom de « rightsizing ». Ce papier décrit une approche zéro dimensionnelle pour estimer les bénéfices obtenus par la millérisation d'un moteur de référence. Le modèle comprend un sous modèle de transfert thermique, basé sur la corrélation du coefficient de convection de Woschni, ainsi qu'un sous modèle de frottements qui permet de prendre en compte l'effet d'une augmentation de la taille. La fermeture prématurée des soupapes d'admission du cycle de Miller tend à réduire l'intensité des mouvements aérodynamiques internes au cylindre, le niveau de turbulence en fin de compression est donc réduit. Ce phénomène augmente la durée de combustion et affecte le rendement. Un modèle de turbulence K-k-ε est utilisé pour estimer l'intensité de la turbulence en fin de compression. Une relation entre la durée de combustion et la turbulence est proposé. Pour le moteur de référence, les gains obtenus par millérisation permettent l'augmentation d'un point de rendement, correspondant à une amélioration d'efficacité d'environ 3%, valeur très significative pour un rendement. ABSTRACT. New environmental regulations are encouraging automakers to focus on over-expanded cycles and to set aside the classic Otto cycle. The Miller cycle is part of this family of cycles and can be applied to spark ignition engines easily by modifying the intake valve closing event. The engine expands more than the actual compression phase. The millerization of an engine is done by increasing the size of the engine and closing the intake valves in advance. The closing time is chosen to follow the same effective compression phase as the reference engine. This process is known as "rightsizing". This paper describes a zero-dimensional approach to estimate the benefits obtained by millerization of a reference engine. The model includes a heat transfer sub-model, based on the Woschni coefficient, as well as a friction sub-model that allows us to take into account the effect of an increase in size. Premature closure of the intake valves in the Miller cycle tends to reduce the intensity of aerodynamic movements within the cylinder, so the level of turbulence at the end of compression is reduced. This phenomenon increases combustion duration and affects efficiency. A K-k-ε turbulence model is used to estimate the intensity of turbulence at the...

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“…Indeed, the environmental constraints of the last few years have seen the application of over-expanded cycles, such as the Atkinson and Miller cycles, which further increase the efficiency of thermal engines [8][9][10][11][12][13]. Car manufacturers are beginning to apply them to their new engines [14][15][16][17][18]. One drawback is that these cycles affect the intake valves by increasing or reducing their opening time, which strongly disturbs the tumble movement.…”

Section: Introductionmentioning

confidence: 99%

Flow Field Parametric Interpolation Using a Proper Orthogonal Decomposition: Application to the Variable Valve Timing Effect on a Tumble In-cylinder Miller Engine Mean Flow

2021

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The current article presents a method to reconstruct the mean velocity field of a cyclic flow for an input parameter value that has not been measured, allowing for the number of tests to be reduced. It is applied to the tumble flow of a gasoline engine following a Miller cycle. New engines often include variable valve timing (VVT) systems to maximize the efficiency of such over-expanded cycles for different operating points. The reconstruction was thus carried out using different offset values of the intake valve lift timing. Experimental data were collected from a transparent engine in an early intake valve closing (EIVC) configuration using particle image velocimetry (PIV). The mean velocity field reconstruction was based on the interpolation of the proper orthogonal decomposition (POD) coefficients. The accuracy of the method was evaluated at different points by comparing the interpolated and the measured flow fields. The accuracy was estimated by calculating the error in the rotation rate of the tumble and the position of its center of rotation. The new mean velocity field set allowed for the position of the tumble’s center of rotation to be closely tracked according to the input parameter and a rotation rate map to be made. Some results on Miller’s cycle could thus be found and the data generated could guide future developments.

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The New BMW Motorrad Boxer Engine with ShiftCam Technology

Cited by 3 publications

References 0 publications

Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Zero-dimensional turbulence modeling of a spark ignition engine in a Miller cycle « Dethrottling » approach using a variable valve timing system

Modélisation 0D turbulente d’un moteur essence en vue de sa Millérisation

Flow Field Parametric Interpolation Using a Proper Orthogonal Decomposition: Application to the Variable Valve Timing Effect on a Tumble In-cylinder Miller Engine Mean Flow

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