{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,14]],"date-time":"2026-02-14T21:17:41Z","timestamp":1771103861244,"version":"3.50.1"},"publisher-location":"400 Commonwealth Drive, Warrendale, PA, United States","reference-count":20,"publisher":"SAE International","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<div class=\"htmlview paragraph\">One of the ways to improve thermodynamic efficiency of Spark Ignition engines is by the optimisation of valve timing and lift and compression ratio. The throttleless engine and the Miller cycle engine are proven concepts for efficiency improvements of such engines.<\/div>\n<div class=\"htmlview paragraph\">This paper reports on an engine with variable valve timing (VVT) and variable compression ratio (VCR) in order to fulfill such an enhancement of efficiency. Engine load is controlled by the valve opening period (enabling throttleless operation and Miller cycle), while the variable compression ratio keeps the efficiency high throughout all speed and load conditions.<\/div>\n<div class=\"htmlview paragraph\">A computer model is used to simulate such an engine and evaluate its improvement potential, while a single cylinder engine demonstrates these results.<\/div>\n<div class=\"htmlview paragraph\">The same base engine was run on the test bench under the Diesel cycle, Otto cycle and Miller cycle conditions, enabling direct thermodynamic comparisons under a wide variety of conditions of speed and load.<\/div>\n<div class=\"htmlview paragraph\">The results show a significant improvement of the Miller cycle over the Otto cycle engine. Comparisons of the Miller engine with the Diesel engine shown that it is possible to have a SI engine with better efficiency than a similar Diesel engine for most of the working conditions.<\/div><\/jats:p>","DOI":"10.4271\/2007-01-0261","type":"proceedings-article","created":{"date-parts":[[2010,7,26]],"date-time":"2010-07-26T18:03:11Z","timestamp":1280167391000},"source":"Crossref","is-referenced-by-count":28,"title":["Direct Comparison of an Engine Working under Otto, Miller and Diesel Cycles: Thermodynamic Analysis and Real Engine Performance"],"prefix":"10.4271","volume":"1","author":[{"given":"Bernardo","family":"Ribeiro","sequence":"first","affiliation":[{"name":"Universidade do Minho, Portugal"}]},{"given":"Jorge","family":"Martins","sequence":"additional","affiliation":[{"name":"Universidade do Minho, Portugal"}]}],"member":"2796","published-online":{"date-parts":[[2007,4,16]]},"reference":[{"key":"ref0","doi-asserted-by":"crossref","unstructured":"Martins, J. Uzuneanu, K Ribeiro, B. Jasansky, O Thermodynamic Analysis of an over-Expanded Engine SAE 2004-01-0617 2004","DOI":"10.4271\/2004-01-0617"},{"key":"ref1","doi-asserted-by":"crossref","unstructured":"Ribeiro, B. Martins, J Kothari, N. Otto and VCR Miller Engine Performance during the European Driving Cycle SAE 2006-01-0440 2006","DOI":"10.4271\/2006-01-0440"},{"key":"ref2","doi-asserted-by":"crossref","unstructured":"Ahmad, T. Theobald, M. A. A Survey of Variable-Valve-Actuation Technology SAE 891674 1989","DOI":"10.4271\/891674"},{"key":"ref3","doi-asserted-by":"crossref","unstructured":"Stone, Richard Kwan, Eric Variable Valve Actuation Mechanisms and the Potential for their Application SAE 890673 1989","DOI":"10.4271\/890673"},{"key":"ref4","doi-asserted-by":"crossref","unstructured":"Hannibal, W. Flierl, R. Stiegler, L. Meyer, R. Overview of Current Continuously Variable Valve Lift Systems for Four-Stroke Spark-Ignition Engines and the Criteria for their Design Ratings SAE 2004-01-1263 2004","DOI":"10.4271\/2004-01-1263"},{"key":"ref5","doi-asserted-by":"crossref","unstructured":"Urata, Y. Umiyama, H. Shimizu, K. Fujiyoshi, Y. Sono, H. Fukuo, K. A Study of Vehicle Equipped with Non-Throttling S.I. Engine with Early Intake Valve Closing Mechanism SAE 930829 1993","DOI":"10.4271\/930820"},{"key":"ref6","doi-asserted-by":"crossref","unstructured":"Flierl, R. Kluting, M. The Third Generation of Valvetrains-New Fully Variable Valvetrains for Throttle-Free Load Control SAE 2000-01-1227 2000","DOI":"10.4271\/2000-01-1227"},{"key":"ref7","doi-asserted-by":"crossref","unstructured":"Drangel, H. Olofsson, E. Reinmann, R. The Variable Compression (SVC) and the Combustion Control (SCC) - Two Ways to Improve Fuel Economy and Still Comply with World-Wide Emission Requirements SAE 2002-01-0996 2002","DOI":"10.4271\/2002-01-0996"},{"key":"ref8","unstructured":"Clarke et al. Internal combustion engine with adjustable compression ratio and knock control 2000"},{"key":"ref9","unstructured":"Brevick Variable compression ratio piston 1998"},{"key":"ref10","unstructured":"Moteki et al. Variable compression ratio mechanism of reciprocating internal combustion engine 2003"},{"key":"ref11","unstructured":"Martins, J. Ribeiro, B. Fuel Consumption Reduction by Adopting a Different Spark Ignition Engine Cycle Advances in Technology and Instrumentation to Guarantee the Reduction of GHG in Different Sectors October 2004 Lisbon, Portugal"},{"key":"ref12","doi-asserted-by":"crossref","unstructured":"Blair, G. P. Design and Simulation of Four-Stroke Engines SAE 1999","DOI":"10.4271\/R-186"},{"key":"ref13","doi-asserted-by":"crossref","unstructured":"Patton, K. J. et al. Development and Evaluation of a Friction Model for Spark-Ignition Engines SAE 890836 1989","DOI":"10.4271\/890836"},{"key":"ref14","doi-asserted-by":"crossref","unstructured":"Sandoval, D. Heywood, J. An improved Friction Model for Spark-Ignition Engines SAE 2003-01-0725 2003","DOI":"10.4271\/2003-01-0725"},{"key":"ref15","unstructured":"Heywood, B. J. Internal Combustion Engines Fundamentals McGraw-Hill 1988"},{"key":"ref16","unstructured":"Ferguson, C.R. Internal Combustion Engines Applied Thermodynamics J. Wiley & Sons 1986"},{"key":"ref17","unstructured":"\u00c7engel, Y. A. Boles, M. A. Thermodynamics An Engineering Approach Third edition McGraw-Hill 1998"},{"key":"ref18","unstructured":"Annand, W.J.D. Roe, G.E. Gas Flow in the Internal Combustion Engine 1974 Foulis, Yeovil"},{"key":"ref19","unstructured":"Ribeiro, Bernardo S. Thermodynamic Optimisation of Spark Ignition Engines at Part-Load Conditions Universidade do Minho Portugal December 2006"}],"event":{"name":"SAE World Congress & Exhibition","location":"Detroit, Michigan, United States","acronym":"ANNUAL","number":"145665","start":{"date-parts":[[2007,4,16]]}},"container-title":["SAE Technical Paper Series"],"original-title":[],"link":[{"URL":"https:\/\/saemobilus.sae.org\/downloads\/papers\/2007-01-0261\/Full%20Text%20PDF","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,6]],"date-time":"2025-10-06T17:04:08Z","timestamp":1759770248000},"score":1,"resource":{"primary":{"URL":"https:\/\/saemobilus.sae.org\/papers\/direct-comparison-engine-working-otto-miller-diesel-cycles-thermodynamic-analysis-real-engine-performance-2007-01-0261"}},"subtitle":[],"proceedings-subject":"SAE Technical Paper Series","short-title":[],"issued":{"date-parts":[[2007,4,16]]},"references-count":20,"URL":"https:\/\/doi.org\/10.4271\/2007-01-0261","relation":{},"ISSN":["0148-7191","2688-3627"],"issn-type":[{"value":"0148-7191","type":"print"},{"value":"2688-3627","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007,4,16]]},"article-number":"2007-01-0261"}}