Overview of Current Continuously Variable Valve Lift Systems for Four-Stroke Spark-Ignition Engines and the Criteria for their Design Ratings

Hannibal, Wilhelm; Flierl, Rudolf; Stiegler, Lutz; Meyer, Renate

doi:10.4271/2004-01-1263

Cited by 39 publications

(16 citation statements)

References 2 publications

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“…At one end of the spectrum, various electro-magnetic and electro-hydraulic systems have been proposed. Such camless systems have been reported to allow the greatest potential for reduction in SI engine breathing losses (10,11) and/or can be used to realize advanced modes of operation such as Controlled Auto Ignition (12,13). However, in general these systems often still have significant issues to overcome including packaging, noise and cost.…”

Section: Introductionmentioning

confidence: 99%

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Cairns¹,

Todd²,

Hoffman³

et al. 2009

SAE Technical Paper Series

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The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191 Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. SAE ABSTRACTThis experimental work was concerned with the combination of internal EGR with an early inlet valve closure strategy for improved part-load fuel economy. The experiments were performed in a new spark-ignited thermodynamic single cylinder research engine, equipped with a mechanical fully variable valvetrain on both the inlet and exhaust. During unthrottled operation at constant engine speed and load, increasing the mass of trapped residual allowed increased valve duration and lift to be used. In turn, this enabled further small improvements in gas exchange efficiency, thermal efficiency and hence indicated fuel consumption. Such effects were quantified under both port and homogeneous central direct fuel injection conditions. Shrouding of the inlet ports as a potential method to increase in-cylinder gas velocities has also been considered.

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Section: Introductionmentioning

confidence: 99%

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Cairns¹,

Todd²,

Hoffman³

et al. 2009

SAE Technical Paper Series

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“…Flexible systems have thus become increasingly attractive as means of achieving optimal engine-in-vehicle operation. Advanced Variable Valve Actuation (VVA) technologies are particularly promising in saving fuel, reducing emissions and increasing Spark-Ignition (SI) engine output [1][2][3][4][5]. Among various VVA options, cam-phasing is gaining broad acceptance, due to its ease of implementation and tangible advantages over conventional fixed-cam engines [6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

A Simulation-Based Approach for Developing Optimal Calibrations for Engines with Variable Valve Actuation

Filipi

Prucka

et al. 2007

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Une approche basée sur la simulation pour le développement de réglages optimaux des moteurs avec système d'actionnement variable de soupape -La technologie d'actionnement variable de soupape (Variable Valve Actuation, VVA) présente un fort potentiel pour augmenter les performances et réduire consommation et pollution. Les avantages du VVA proviennent d'une meilleure aération et de la possibilité de contrôler les résidus internes. Par contre, l'addition de variables de contrôle supplémentaires dans un moteur VVA augmente la complexité du système, ce qui nécessite la mise au point d'une stratégie de contrôle optimale afin d'en tirer tous les bénéfices. L'approche traditionnelle reposant sur l'expérimentation s'avère trop onéreuse dans ce cas du fait de l'augmentation exponentielle du nombre de tests. Ce projet propose comme alternative de définir le réglage des soupapes comme un problème d'optimisation. Il identifie les simulations nécessaires au développement d'une méthode générique capable d'intégrer un nombre croissant de degrés de liberté afin de développer un outil de grande fidélité pour la prédiction des effets de différents dispositifs. Puisque la résolution d'un problème d'optimisation requiert l'évaluation de centaines de fonctions, l'utilisation directe d'une simulation hautefidélité demande des temps de calculs beaucoup trop longs. En remplacement, un réseau artificiel de neurones est entraîné avec des résultats de simulation haute-fidélité et utilisé pour représenter la réponse du moteur à différentes combinaisons de variables de contrôle, et ce avec des temps de calcul beaucoup plus courts. Cet article décrit une méthode basée sur la simulation, apporte des détails sur les techniques de modélisation haute-fidélité et démontre une application à un prototype de moteur à essence à quatre cylindres et double arbre à cames indépendant. Abstract

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“…VVA throttle-free load control can be achieved by different intake valve actuation strategies such as: combined variable valve lift, duration and timing [3][4][5]7,8,[10][11][12][13][14][15][16]. The solution used by BMW with its Valvetronic-Vanos mechanism [4] is outstanding.…”

Section: Introductionmentioning

confidence: 99%

“…Much of the research effort on improving SI engine efficiency therefore focuses on throttle-free load control. Two methods are being intensively investigated in order to obtain unthrottled operation: lean burn and stratified-charge GDI (see [1,2,9,10] or Mitsubishi GDI, VW FSI, Mercedes CGI, which are on the market) and VVA with a stoichiometric mixture (see [2][3][4][5]7,8,[10][11][12][13][14][15][16] and BMW Valvetronic, on the market since 2001). Both techniques have demonstrated a significant improvement in fuel economy.…”

Section: Introductionmentioning

confidence: 99%

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Idle Operation with Low Intake Valve Lift in a Port Fuel Injected Engine

Clenci

Bîzîiac²,

Podevin

et al. 2013

Energies

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Abstract:Reducing fuel consumption is a prime objective in the automotive industry in order to meet regulatory and customer demands. Variable valve actuation offers many opportunities for improving the spark ignition engine's performance in areas such as fuel economy and pollutant emissions. Our studies revealed that the ability to control maximum intake valve lift does indeed offer the ability to control intake air mass, but also has the added benefit that it improves the fuel-air mixing process thanks to an increased turbulence, caused by the increased intake flow velocity. This is particularly important at idle and low part loads when low maximum lifts are to be used for improving the fuel economy or for achieving the required power. The paper focuses on the experimental results obtained when approaching idle operation with different intake valve laws. Results indicating the potential of using low intake valve lift for fuel economy and cyclic dispersion improvement are presented in this paper.

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Overview of Current Continuously Variable Valve Lift Systems for Four-Stroke Spark-Ignition Engines and the Criteria for their Design Ratings

Cited by 39 publications

References 2 publications

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

A Simulation-Based Approach for Developing Optimal Calibrations for Engines with Variable Valve Actuation

Idle Operation with Low Intake Valve Lift in a Port Fuel Injected Engine

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