Engine Operating PhysicsMOT/PHYM-E

Who should attend?

  • This course provides a deeper knowledge on engine operating physics, under the mechanical aspects, air loading, fuel injection, ignition, exhaust gas after-treatment.
Audience :
  • Engineers and technical staff from design department, testing department wishing to improve their knowledge on following items: engine operation, physics of engines, components design.

Level : Foundation

Course Content

  • Week 1

      • Engine thermodynamic operating (1.5 days)
      • History.
      • Thermodynamics basic knowledge: first and second principles, engine efficiency limits. Internal energy, enthalpy, entropy. Ideal gas equation. Laplace equation. Thermodynamic cycles, Beau de Rochas cycle.
      • Compressor isentropic efficiency.
      • Engine architecture - Performance and efficiency parameters (2 days)
      • Geometric parameters: bore, stroke, volumetric ratio, timing diagram.
      • Effective mean pressure: MEP, MFP, MIP.
      • Real cycle, differences with theoretical cycle.
      • Global efficiency: analysis using the 4 efficiencies and setting parameter influence.
      • Fuel/air ratio, volumetric efficiency: calculation of the main engine parameters at stabilized rpm.
      • Adaptation to the vehicle: Willans line.
  • Week 2

      • Engine mechanics (1.5 days)
      • Acyclism
      • Determine the movements of stresses due to gas pressure in the parts.
      • Stresses caused by gas pressure and inertia stresses, impact of the conrod spacing on acyclisms.
      • Acyclism consequences and solutions to limit their impact on the powertrain.
      • Balancing
      • Inertia stresses caused by the rotating weight and the alternative weight.
      • Calculation of rotating and alternating inertia forces.
      • Timing: description of the different valve control types, lift law, valve timing.
      • Air loop (2 days)
      • Link between loading and performances. Fluid mechanics.
      • Air loading.
      • Variable timing: presentation of the main technologies and their applications.
      • Turbocharging: operating, technology, mapping, adaptation process.
  • Week 3

      • Combustion (2 days)
      • Air and fuel. Heating value. Ignition equation. Stoichiometric quantity. Equivalence ratio. Specific energy of an air/fuel mixture. Application exercise.
      • Gasoline combustion: flame front propagation, influence of turbulence; influence of the burning rate (HLC) and of the combustion timing (CA 50) on the efficiency; exhaust gas composition depending on the equivalence ratio; calculation of specific emissions, abnormal combustions (knock, pre-ignition, rumble).
      • Diesel combustion: self-inflammation delay, pre-mixture and diffusion flames, formation of pollutants (PM, NOx, HC, CO). Common-rail injection systems; swirl number, EGR.
      • Fuels (1 day)
      • Fuels groups: fuel main required properties for engine operating (heat value, volatility), octane and cetane ratings, Diesel fuel resistance to cold, sulfur content, …
      • Manufacturing process of fuels in a refinery.
      • Biofuels: fuels-ethanol mixtures, vegetable oils, fatty acid esters.
      • Exhaust gas after-treatment (0.5 days)
      • Structure and operating of oxidation catalysts (Diesel) and trifunctional ones (gasoline). Starting, efficiency. Ageing mechanisms. OSC (Oxygen Storage capacity). Oxygen probe. NOx traps, SCR (Selective Reduction Catalyst). Particles filtration.
  • Week 4

      • Materials - Mechanical strength (1.5 days)
      • Metallurgist basic tools: iron/carbon diagram, TTT, CCT. Characteristics of the alloy steels used in the automotive industry: cast irons, steels, alumina. Rough casting manufacturing processes. Surface treatment. Parts mechanical properties: Young’s modulus, minimum yield, shear rating. Analysis of the engine major parts whose material and manufacturing process have to be chosen.
      • Part damage modes (1 day)
      • Thermal, mechanical and tribologic damages. Goodmann diagram. Stribeck curve.
      • Vibro-acoustics/NVH (1 day)
      • Waves and sound: magnitudes defining a wave, propagation mode (air, solids). NVH vocabulary: dB, dBA, harmonics, resonance …
      • Signal creation and lock-on, analysis and interpretation (sonogram, tracking).
      • Powertrain noises and vibrations. Attenuation, isolation. Vibration impact on the surrounding parts. Line shafting vibration.

Learning Objectives

  • Upon completion of the course, participants will be able to:
  • calculate real flow sections in the cylinder head, in EGR circuits or any other fluid circuit,
  • understand and apply the calculation formulae used during dyno bench tests,
  • analyze some test results on emissions and efficiency,
  • analyze the component damage and failure causes,
  • understand the language and the tools used to analyze vibrations.

Ways & Means

  • Many exercises simulating reveryday situations in every chapter.