This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
New Downsized Diesel Engine Concept with HCCI Combustion at High Load Conditions
Technical Paper
2015-01-1791
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
A light duty downsized engine, named as “z-engine”, was developed, built and tested on the experimental rig. This engine is a two-stroke diesel with a split compression process and poppet valve for the gas exchange. The split compression process provides sufficient time for the longer exhaust process (over 180 CA degrees). The first stage of fresh air compression takes place in a turbocharger, the second part of the compression takes place in the mechanically driven piston compressor with PR of about 4.5 - 5.5. A very brief induction period, which lasts for about 10-22 CA degrees, is followed by a short final compression in the cylinder in which mixing occurs. The external piston compressor which provides all cylinders with a fresh charge, has relatively cold walls and its outlet is connected to an intercooler, so the total compression work is reduced and the fresh charge has a considerably lower temperature in comparison with a conventional diesel engine. Due to the absence of the scavenging process and a large dead volume which is present during the induction process, there is an increased EGR in the z-engine at all operating modes. The increased internal EGR and low temperature at TDC result in low NOx emissions even for normal air/diesel mixture formation and combustion. The total fuel efficiency of the z-engine is approximately same, if not higher, than that of a conventional diesel engine. Due to the specific working process of the z-engine, the HCCI process may be realized even at the full torque (BMEP∼30 bar) and maximum power modes. To achieve this the injection should be carried out at the end of the exhaust and should be terminated prior to the intake starts, when there is no fresh air, and there is a low pressure and high temperature in the cylinder. All these factors result in the rapid evaporation. An intensive intake process disintegrates the remaining of fuel sprays, resulting in formation of homogenous or near homogenous charge and decreases the in-cylinder temperature, which slows down pre-ignition reactions. The increased EGR and low temperature at the final compression stages prolong the ignition delay period and presence of the highly turbulent flow results in in-cylinder homogeneous conditions. A pilot injection or electrical spark initiates ignition of the homogeneous mixture at the optimal moment.
To reduce the fuel spray tip penetration in low pressure conditions in the cylinder a pintle-type injector is used for the main fuel injection process. CFD modelling using ANSYS/FLUENT software was performed to produce recommendations for preventing the fuel impingement onto the walls. The thermodynamic analysis using GT-Power software was performed to optimize the piston compressor ports timing. The mixture formation process and combustion were simulated and optimized with deployment of DIESEL-RK software. The detailed chemistry of pre-ignition reactions was simulated to predict the ignition delay period. The obtained computational results were verified using published experimental data.
Recommended Content
Authors
Topic
Citation
Kuleshov, A., Mahkamov, K., Janhunen, T., Akimov, V. et al., "New Downsized Diesel Engine Concept with HCCI Combustion at High Load Conditions," SAE Technical Paper 2015-01-1791, 2015, https://doi.org/10.4271/2015-01-1791.Also In
References
- http://www.aumet.fi
- Tiainen J , Saarinen A , Grönlund T , Larmi M Novel Two-stroke Engine Concept, Feasibility Study SAE Technical Paper 2003-01-3211 2003
- Grönlund Tore and Larmi Martti Valve Train Design for a New Gas Exchange Process SAE Technical Paper 2004-01-0607 2004
- http://www.diesel-rk.com.
- Kuleshov A.S. Multi-Zone DI Diesel Spray Combustion Model for Thermodynamic Simulation of Engine with PCCI and High EGR SAE Technical Paper 2009-01-1956 2009
- Zvonov , V.A. Internal combustion engines toxicity Moscow Mashinostroenie 1973
- Miller , J.A. , Bowman , C.T. Mechanism and modeling of nitride. Chemistry in Combustion Prog. Energy Combustion Science 1989 15 287 338
- Bochkov , M.V. , Lovachev , L.A. , Hvisevich , S.N. Formation of the Nitrogen Oxide (NO) at Laminar Flame Propagation in the Homogeneous Air-Methane Mixture FGV 34 1998 1
- Bochkov , M.V. , Lovachev , L.A. , Hvisevich , S.N. Numerical Modeling the NOx Formation at Air-Methane Mixture Combustion at Condition of Coupled Processes of Chemistry Kinetic and Molecules Diffusion Mathematical Modeling. 1997 3 9 13 28
- Kuleshov A.S. Model for predicting air-fuel mixing, combustion and emissions in DI diesel engines over whole operating range SAE Technical Paper 2005-01-2119 2005
- Kuleshov A.S. Use of Multi-Zone DI Diesel Spray Combustion Model for Simulation and Optimization of Performance and Emissions of Engines with Multiple Injection SAE Technical Paper 2006-01-1385 2006
- Zheng Jincai A Study of Homogeneous Ignition and Combustion Processes in CI, SI, and HCCI Engine Systems PhD Thesis Drexel University 2005
- Wijesinghe , J. and Hong , G. Experimental Investigation of Spark Assisted Auto-Ignition Combustion in a Small Two-Stroke Engine SAE Technical Paper 2008-01-1665 2008
- He , X. Donovan , M.T. Zigler , B.T. Palmer , T.R. Walton , S.M. Wooldridge M.S. , Atreya A. An Experimental and modeling study of iso-octane ignition delay times under homogeneous charge compression ignition conditions Combustion and Flame 142 2005 266 275
- https://www-pls.llnl.gov/?url=science_and_technology-chemistry-combustion-mechanisms.
- Kuleshov , Andrey Kozlov A.V. , Mahkamov Khamid Self-Ignition delay Prediction in PCCI direct injection diesel engines using multi-zone spray combustion model and detailed chemistry SAE Technical Paper 2010-01-1960 2010
- Jia Ming , Xie Maozhao , Liu Hong , Lam Wei-Haur , Wang Tianyou Numerical simulation of cavitation in the conical-spray nozzle for diesel premixed charge compression ignition engines Fuel 01 2011 90 8 2652 2661
- Sun , Weninger , Reitz Adaptive injection strategies (AIS) for ultra-low emissions diesel engines DEER 2007
- Jia , M. , Hou , D. , Li , J. , Xie , M. et al. A Micro-Variable Circular Orifice Fuel Injector for HCCI-Conventional Engine Combustion - Part I Numerical Simulation of Cavitation SAE Technical Paper 2007-01-0249 2007
- Lyshevsky A.S. Fuel atomization in marine diesels Leningrad 1971
- Grekhov L.V. , Ivaschenko N.F. , Markov V.F. Fuel systems and diesel control Moscow Legion-Autodata 2005
- Winklhofer E. , Kull E. , Kelz E. , Morozov A. Comprehensive Hydraulic and Flow Field Documentation in Model Throttle Experiments under Cavitation Conditions ILASS 2001 547 579
- Schmid Andreas Experimental characterization of the two phase flow of a modern, piezo activated hollow cone injector DISS. ETH NO.20852 2012
- Obokata , T. , Long , W. , and Ishima , T. PDA and LDA Measurements of Large Angle Hollow Cone Spray Proposed for Hot-Premixed Combustion Type Diesel Engine SAE Technical Paper 960772 1996 10.4271/960772
- Yang , X. , Takamoto , Y. , Okajima , A. , Obokata , T. et al. Comparison of Computed and Measured High-Pressure Conical Diesel Sprays SAE Technical Paper 2000-01-0951 2000 10.4271/2000-01-0951
- Sazhin S.S. , Kristyadi T. , Abdelghaffar W.A. , Heikal . M.R. Models for fuel droplet heating and evaporation: Comparative analysis Fuel 2006 85 1613 1630
- Sazhin S. , Martynov S.B. , Kristyadi T. , Crua C. , Heikal M.R. Diesel fuel spray penetration, heating, evaporation and ignition: modelling vs. Experimentation Int. J. of Engineering Systems Modelling and Simulation 2008 1 1 1 19
- Stehlig Jurgen , Dingelstadt Rene , Muller Rolf , Taylor James Luftansaugmodule Mit Integrierter Kaskadierter Ladeluftkuhlung MTZ 3 2013 218 224