Internal Combustion Engines B

Fuels and Emissions

• Refining process, chemical structure of hydrocarbons, types and designation of fuel products, availability.

• Fuel properties: composition (C/H ratio, S-content), density, viscosity, lower heating value, ignition performance (CCAI).

• Alternative fuels and their potential of emission reduction for (marine) reciprocating internal combustion engines.

• Overview of types, formation and hazards of harmful emissions: gaseous (CO2, CO, UHC, SOX, NOX) and particles (PM).

• Measurement techniques and equipment including units of emission measurement and methods of conversion.

• Emission abatement methods, legislation and technology (1. Choice of fuel, 2. Primary methods for engine/combustion optimization: injection (timing/pressure/rate/shape), air humidity, air inlet temperature, compression ratio, air excess ratio, variable turbine geometry (VTG), fuel/water emulsion, water injection, exhaust gas recirculation (EGR), 3. Secondary methods (end of pipe solutions): selective catalytic reduction (SCR), scrubbing, carbon capture).

Combustion

• Stoichiometric number, mol and mass balance of combustion process, analysis of exhaust gas composition, practical determination of air excess ratio from emission measurements.

• Properties of substances and mixtures: series expansion for specific heat, internal energy, enthalpy and entropy.

• Thermodynamics of combustion: precise definition of heat of combustion.

• Chemistry and physics: atomizing, ignition (conditions, delay), explosion diagram, flame shape, thermal theory (Arrhenius), reaction mechanisms, chain reactions, premixed and diffusive combustion.

• Heat release: Determination of Net and Gross Apparent Heat Release as well as Combustion Reaction Rate by reversed simulation algorithm, practical measurement of in-cylinder pressure and instantaneous volume (incl. assessment of Top Dead Centre), maximum pressure and temperature as a result of heat release.

• Modelling of heat release by single and double Wiebe model, basic principles of single zone cylinder process simulation.

Heat Transfer

• Mean values of heat transfer between gas and wall: summation over time and location.

• Heat transfer mechanisms: conduction, convection, gas radiation and flame radiation, order of magnitude of the different contributions.

• Heat transfer coefficients: empirical methods (Nusselt, Eichelberg), methods based on dimension analysis (Sitkei, Annand, Woschni).

• Gas velocities in the cylinder including swirl en squish.