Gas exchange in valved two-stroke SI engine
Treść / Zawartość
The paper describes the work of high speed charged spark ignition overhead poppet valve two-stroke engine, which enables to achieve higher total efficiency and exhaust gas emission comparable to four-stroke engines. The work of such engines is possible by proper choice ofvalve timings, geometrical parameters of inlet, outlet ducts and charge pressure. The engine has to be equipped with direct fuel injection system enabling lower emission of pollutants. The work is based on theoretical considerations performed in GT-Power in previous authors' research and carried out in CFD code (KIVA 3 V) for different engine configurations. The initial results included in the paper show influence of inlet port geometry and charge pressure on engine scavenging process. Additionally, optimum fuel spray injector position was considered in order to obtain proper fuel vaporization and avoid significant wall-wetting. The simulation results show that the nitrogen oxides arę considerably reduced in comparison to four-stroke engines because ofhigher internal exhaust gas recirculation. The innovation of this proposal is applying of poppet intake and exhaust valves with turbocharging in the two-stroke engine and obtaining a significant downsizing effect. The conclusion shows the possibilities of proper gas exchange process in this type of two-stroke engine and thus, the feasibility of its application as a power unii for transportation means with higher total efficiency than traditional engines with possible change of engine work in two modes: two- and four-stroke cycles.
Bibliogr. 9 poz., rys.
-  Amsden, A. A., O’Rourke, P. J., Butler, T. D., KIVA-II: A Computer Program for Chemically Reactive Flows with Sprays, Los Alamos National Laboratory, LA-11560-MS.
-  Amsden, A. A., KIVA-3: A KIVA Program with Block-Structured Mesh for Complex Geometries, Los Alamos National Laboratory, LA-12503-MS.
-  Amsden, A. A., KIVA-3V: A Block-Structured KIVA Program for Engines with Vertical or Canted Valves, Los Alamos National Laboratory, LA-13313-MS.
-  Blair, G. P., Design and Simulation of Two-Stroke Engines, SAE Inc., Warrendale 1996.
-  Heywood, J. B., Internal Combustion Engine Fundamentals, McGraw-Hill, Inc., 1988.
-  Mitianiec, W., Buczek, K., A New Approach in Development of Two-Stroke Engine Combustion Engines, PTNSS–2009–SC–042, Bielsko-Biala 2009.
-  Mitianiec, W., Buczek, K., A New Design of Ecologic Two-St roke Engine, 12 EAEC European Automotive Congress, Bratislava 2009.
-  Mitianiec, W., Buczek, K., A Valved Two-Stroke Engine as a New Power Source, Journal of KONES, 2009.
-  Osbourne, R., et al., The 2/4 SIGHT Project – Development of a Multi-Cylinder Two-Stroke/Four-Stroke Switching Gasoline Engine, SAE Technical Paper 384-20085400.