# Engine Operating Physics

PHYM-EN-A
This course can be adapted to virtual classroom mode

## 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.
Public :
• 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

• 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

• 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

• 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

• Variable timing: presentation of the main technologies and their applications.
• Turbocharging: operating, technology, mapping, adaptation process.
• Week 3

### Combustion

• 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

• 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

• 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

• 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

• Thermal, mechanical and tribologic damages. Goodmann diagram. Stribeck curve.
• ### Vibro-acoustics/NVH

• 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.
To French entities : IFP Training is QUALIOPI certified ; you may contact your OPCO about potential funding.