New Operating Strategies Afforded by Fully Variable Valve Trains

Turner, J. W. G.; Bassett, Michael; Pearson, Richard; Pitcher, Graham; Douglas, K. J.

doi:10.4271/2004-01-1386

Cited by 39 publications

(16 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This relation A spool = f (X spool ) is called the area-schedule. In the case of Q ono f f 1 and Q ono f f 2 , the corresponding orifice areas A ono f f 1 and A ono f f 2 are set to either 0 or maximum depending on the state of the particular on-off valve.…”

Section: A Mathematical Model Of the Systemmentioning

confidence: 99%

“…It has been shown that a flexible air handling system with the capability of varying the valve lift, timing, duration or a combination of these parameters can offer significant improvements in the performance and efficiency over a wide range of operating conditions [1]. At present, camshaft based variable valve actuation systems are offered by a number of automobile manufacturers [2]- [4].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modeling and control design of a camless valve actuation system

Gillella

Sun

2009

2009 American Control Conference

View full text Add to dashboard Cite

This paper presents the modeling and control design of a new fully flexible engine valve actuation system which is an enabler for camless engines. Unlike existing electromechanical or servo actuated electro-hydraulic valve actuation systems, precise valve motion control is achieved with a hydromechanical internal feedback mechanism. This feedback mechanism can be turned on or off in real-time using simple two state valves which helps reduce the system cost and enables mass production. Since the external control only activates or deactivates the internal feedback mechanism, the trajectory of the entire closed-loop system is purely dependent on the design parameters of the internal feedback system. A mathematical model of the system is developed to evaluate the effect of each of the design parameters. The "Area-schedule" is identified as the key design feature which affects the trajectory of the closedloop system. It needs to be designed systematically to optimize the performance of the system as well as improve its robustness. By treating this feature as the feedback control variable, the design problem is transformed into a nonlinear optimal control problem which is later solved using the numerical dynamic programming method. The effectiveness of the designed areaschedules is verified with simulations.

show abstract

Section: A Mathematical Model Of the Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling and control design of a camless valve actuation system

Gillella

Sun

2009

2009 American Control Conference

View full text Add to dashboard Cite

show abstract

“…However, almost all the previously proposed air hybrid engine concept (Tai et al, 2003;Schechter, 1999Schechter, , 2000Turner et al, 2004Turner et al, , 2005Kang et al (2008); Andersson et al, 2005;Trajkovic et al, 2008;Donitz et al, 2008) involve the complexity of the camless actuation system that was assumed to be necessary to convert the engine to compressor or expander, and the precision of control that was assumed to be necessary for such a system. A new concept is proposed here to overcome such limitation by making use of practical variable valve trains and production technologies.…”

Section: Introductionmentioning

confidence: 99%

Analysis of a production-oriented air hybrid engine concept and its performance

Zhao

Psanis

2011

IJPT

View full text Add to dashboard Cite

In this paper, an air hybrid engine concept with an one-way intake system will be described and analysed. The investigation started with systematic studies on the effect of various valve opening and closing events on the performance of Compressor Mode (CM) and Expander Mode (EM) operations. After having defined the optimal valve timings for CM and EM operations over a range of engine speeds, the effect of other operating parameters on the performance of the air hybrid engine, such as buffer (or auxiliary) chamber volume, airtank volume and pressure, etc., is examined. It is shown that this concept can be readily implemented in production engines with existing production VVA technologies. The predicted results indicate that it is capable of performing good regenerative braking and large driving torque to start and motor the engines using the stored compressed air.

show abstract

“…Through systematic studies, it was found that when the opening timing of Intake valve (5) shifts to 110°BBDC at the expansion process (the normal intake stroke), cylinder Figure 12. Because of the reduced negative work and full expansion, much higher motoring imep m values are generated.…”

Section: Valves Timing Optimization For Emmentioning

confidence: 99%

“…In the previous proposed air hybrid concepts [1][2][3][4][5][6][7][8], the air hybrid operation requires the use of fully variable valve actuation systems, weather it is electromechanical, hydraulic, or pneumatic camless system. Simulations made by Tai et al [1] show round-trip efficiency of 36%, 38% reduction in fuel consumption and 64% fuel economy improvement.…”

Section: Introductionmentioning

confidence: 99%

A Low Cost Air Hybrid Concept

Lee

Zhao

2010

Oil & Gas Science and Technology

View full text Add to dashboard Cite

Résumé -Un concept hybride à air et à bas prix -Le moteur hybride à air absorbe l'énergie cinétique du véhicule en cas de freinage, la stocke sous forme d'air comprimé, puis la réutilise pour faire avancer le véhicule en circulation ou en accélération. Capter, stocker et réutiliser cette énergie et créer ainsi une puissance plus importante peut donc permettre de plus grandes économies de carburant, surtout en ville et zone urbaine, lorsque les conditions de circulation imposent de nombreux arrêts et démarrages. Pour pouvoir réutiliser l'énergie cinétique, on distingue trois modes de base d'utilisation du véhicule : les modes compression (MC), expansion (ME) et standard. Un moteur hybride à air et à bas prix a été proposé et étudié. Un tel moteur peut être opéré par le biais de technologies de production, comme le VVT et la désactivation des soupapes. Dans ce travail, des analyses systématiques de performance ont été menées via des modèles dynamiques détaillés utilisant le logiciel Ricardo WAVE. Une optimisation des soupapes a été effectuée dans l'objectif d'un fonctionnement plus efficace du système et pour obtenir une pression effective moyenne de freinage plus élevée pour les modes MC et ME, respectivement. Abstract -A Low Cost Air Hybrid Concept -The air hybrid engine absorbs the vehicle kinetic energy during braking, stores it in an air tank in the form of compressed air, and reuses it to propel a vehicle

show abstract

New Operating Strategies Afforded by Fully Variable Valve Trains

Cited by 39 publications

References 8 publications

Modeling and control design of a camless valve actuation system

Modeling and control design of a camless valve actuation system

Analysis of a production-oriented air hybrid engine concept and its performance

A Low Cost Air Hybrid Concept

Contact Info

Product

Resources

About