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Thermodynamic Analysis of Variable Valve Timing Infuence on SI Engine Efficiency
Technical Paper
2001-01-0667
ISSN: 0148-7191, e-ISSN: 2688-3627
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Event:
SAE 2001 World Congress
Language:
English
Abstract
The large number of mechanical, electro-magnetic and oleo-dynamic systems for variable valve actuation developed by automotive suppliers demonstrates the great interest that is being devoted to their potential application on internal combustion engines.
In the paper, a possible strategy to realize an original engine load control by means of both intake and exhaust variable valve timing (VVT) is briefly presented and the thermodynamic analysis of the performance obtainable with this solution is carried out. The peculiarity of this strategy is that it is possible to directly recirculate the desired mass of exhaust gas with less limitation with respect to the external duct architecture. To highlight its potentiality this solution has been compared with two different engine architectures:
- a traditional Spark Ignition (SI) engine, where the load control is demanded to the throttle body;
- an engine equipped with a VVT system only on the intake valves, where the load control is performed by means of the well-known Early Intake Valve Closing (EIVC) strategy.
The proposed engine load control technique shows a relevant efficiency increase at partial load, with respect to both throttled and EIVC engines. The obtained results are certainly overestimated, due to the theoretical thermodynamic approach used to compare the different engine architectures, but the relevant efficiency increase shown in the paper seems to leave a good possibility to find in real experimentation a still appreciable improvement with respect to a throttled engine.
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Citation
Moro, D., Ponti, F., and Serra, G., "Thermodynamic Analysis of Variable Valve Timing Infuence on SI Engine Efficiency," SAE Technical Paper 2001-01-0667, 2001, https://doi.org/10.4271/2001-01-0667.Also In
References
- Stivender D.L. “Intake Valve Throttling (IVT) - A Sonic Throttling Intake Valve Engine” SAE Paper 680339
- Tuttle J.H. “Controlling Engine Load by means of Late Intake-Valve Closing” SAE Paper 800794
- Nuccio P. “Variable Valve Timing as a means to Control Engine Load” FISITA Paper 82071
- Tuttle J.H. “Controlling Engine Load by means of Early Intake-Valve Closing” SAE Paper 820408
- Payri F. Boada F. Maclan V. “Reduction of pumping losses by the use of a variable valve timing system” Proceeding of Instn. Mecdh. Engrs 198 15 295 300 1984
- Elrod A.C. Nelson M.T. “Development of a variable Valve Timed Engine to Eliminate the Pumping Losses Associated with Throttled Operation” SAE Paper 860537
- Gray C. “A Review of Variable Engine Valve Timing” SAE Paper 880386
- Freudenstein F. Maki E.R. Tsai L. W. “The Syntesis and Analysis of Variable Valve-Timing Mechanisms for Internal-Combustion Engines” SAE Paper 880387
- Lenz H.P. Wichart K. Grunden D. “Variable Valve Timing - A Possibility to Control Engine Load without Throttle” SAE Paper 880388
- Ma T. H. “Effect of Variable Engine Valve Timing on Fuel Economy” SAE Paper 880390
- Stone R. Kwan E. “Variable Valve Actuation Mechanisms and the Potential for their Application” SAE Paper 890673
- Ahmad T. Theobald M.A. “A Survey of Variable-Valve-Actuation Technology” SAE Paper 891674
- Dresner T. Barkan P. “A Review of Variable Valve Timing Benefits and Modes of Operation” SAE Paper 891676
- Demmelbauer-Ebner W. Dachs A. Lenz H.P. “Variable Valve Actuation Systems for the Optimization of Engine Torque” SAE Paper 910447
- Kreuter P. Heuser P. Schebitz M. “Strategies to Improve SI-Engine Performance by Means of Variable Intake lift, Timing and Duration” SAE Paper 920449
- Geringer B. Mikulic L. Schommers J. Wolf K Ebersbach G Kramer M. Maly R. “Fully Variable Valve Timing - Another Large Step Towards Optimum Spark Ignition Engines” SAE Paper 925103
- Theobald M. A. Lequesne B. Henry R. “Control of Engine Load via Electromagnetic Valve Actuators” SAE Paper 940816
- Moriya Y. Watanabe A. Uda H. Kawamura H. Yoshioka M. “A Newly Developed Intelligent Variable Valve Timing System - Continuously Controlled Cam Phasing as Applied to a New 3 Liter Inline 6 Engine” SAE Paper”, SAE Paper 960579
- Miller R. H. Davis G.C. Newman C.E. Levin M.B. “Unthrottled Camless Valvetrain Strategies for Spark-Ignited Engines” Proc. ASME ICE 29-1 81 94 1997
- Henry R. R. Lequesne B. “A Novel, Fully Flexible, Electro-Mechanical Engine Valve Actuation System” SAE Paper 970249
- Berg M. Kachel G. Kuhn P. “Mechanical Fully-Flexible Valve Control with delta-st” SAE Paper 970251
- Heywood J.B. 1988 Internal Combustion Engines Fundamentals McGraw Hill