Improvement of Processes in Combustion Chambers of Piston Engines Converted to Hydrogen

This book is devoted to the improvement of thermophysical processes of hydrogen injection, formation of a hydrogen-air mixture, combustion, flame propagation, and heat exchange with the walls of the combustion chamber occurring in serial diesel and gasoline engines converted to hydrogen. It presents research where "process improvement" refers to organization that would minimize nitrogen oxide emissions and heat losses with the walls and reduce thermal loads on the combustion chamber surfaces and the heat-stressed state of the main parts (piston, cylinder head and liner). Improvement is mainly achieved through the use of optimal values of engine parameters, such as design (combustion chamber shape; hydrogen injector design; intensity of vortex motion generated in the intake channel, etc.) and adjustable (hydrogen-air mixture composition; injection moment, duration and pressure; degree of exhaust gas recirculation, etc.) parameters. These are determined based on the results of numerical and full-scale experiments on the hydrogen engines under study. At the end of each part of the book, practical recommendations are given for converting serial gasoline and diesel engines to hydrogen. Addresses the main technical problems encountered converting traditional serial diesel and gasoline engines to hydrogen; Presents numeric models and experiments on thermophysical processes in serial Diesel/Otto engines converted to hydrogen; Details the features of thermophysical processes in the combustion chambers of hydrogen engines. Inhaltsverzeichnis A brief overview of the studies of the operation process of hydrogen-diesel engine.- The peculiarities of the operational process of diesel engine with direct injection of hydrogen gas.- A 3D mathematical model of turbulent motion, mixture, combustion and formation of nitrogen oxides in the hydrogen-diesel engine s cylinder.- Fundamental equations of momentum, energy, diffusion and continuity.- Modeling of the processes of combustion and formation of nitrogen oxides.- A brief description of the turbulence model .- Brief description of the numerical method for solving a system of equations.- Examples of solving test problems of the operation process of hydrogen diesel engine.- Technical characteristics of the hydrogen-diesel and base diesel engines and selection of initial experimental data required for numerical calculation.- 3D model verification using the hydrogen-diesel engine s experimental indicator diagram.- Comparative analysis of the operation processes of hydrogen-diesel and base diesel engines.- Influence of the design parameters on environmental and efficiency indicators of hydrogen-diesel engine.- Influence of the combustion chamber shape of hydrogen diesel engine.- Influence of compression ratio on a hydrogen-diesel engine.- Effect of the air swirling intensity at the end of compression in a hydrogen-diesel engine.- Influence of the design of the injector of hydrogen gas.- The influence of the adjustable parameters on environmental and efficiency indicators of hydrogen-diesel engine.- The influence of excess air ratio.- Cyclic dose of injected hydrogen and time of its delivery.- Influence of air temperature during the filling process.- Effect of fuel injection advance angle.- Analysis of the research results. Selection of optimal values of the design and adjustable parameters of hydrogen-diesel engine with improved environmental and efficient characteristics.- Conclusion and practical recommendations on converting serial diesel engines to hydrogen.- 3D Modeling of working process of the hydrogen engine with spark ignition running on lean fuel mixture.- Experimental hydrogen engine and its features.- Verification of the 3D Model.- Modeling of formation of NOx in the combustion chamber of the hydrogen engine working on the lean fuel with recirculation of the exhaust gases.- Features of exhaust gas recirculation (EGR) in a hydrogen engine.- Features of determining the degree of EGR on an experimental hydrogen engine.- Results of experimental research and simulation of the working process and the formation of nitrogen oxides in a hydrogen engine with EGR.- The effect of EGR on the indicator indicators of a hydrogen engine.- The effect of EGR on the formation of nitrogen oxides in the combustion chamber of a hydrogen engine.- Influence of the degree of EGR on the local parameters of the working fluid in the combustion chamber of a hydrogen engine running on a depleted mixture.- Local heat exchange in the combustion chamber of a hydrogen engine running on a lean fuel mixture.- A brief description of the method developed for studying the local heat transfer and heat stress state of the main parts of hydrogen engine.- The results of modeling of thermal loads on the piston fire surface.- Unsteady processes of hydrogen flame propagation and heat exchange in a narrow annular gap between the piston and the cylinder.- The influence of the Piston heat belt sleeve gap on the heat exchange in the combustion chamber of the engine depending on the fuel utilized.- Hydrogen Flame Propagation from a Variable Volume Combustion Chamber in a Narrow Moving Annular Gap.- Conclusion and practical recommendations on converting serial gasoline engines to hydrogen. Autorenportrait Dr. Revaz Kavtaradze, Dipl. Ing. Habil. is Professor and Chief Researcher, Department of Thermal Power Plants, Institute of Machine Mechanics, Tbilisi, Georgia Dr. Natriashvili Tamaz, Dipl.Ing. Habil. Professor, is Director-Chief Researcher, Department of Thermal Power Plants, Institute of Machine Mechanics, Tbilisi, Georgia. Dr. Gennadi Zikoridse, Dipl.Ing. is Professor of Powertrain Engineering , Head of Vehicle Research Institute at University of Applied Sciences Dresden. Germany. Dr. Merab Glonti, Dipl.Ing. Habil. is Research Fellow, Department of Thermal Power Plants, Institute of Machine Mechanics, Tbilisi, Georgia.