5 days MOT/MOTD-E
- Engineers and technical staff involved in the design, development and testing of diesel engines and equipment.
- Well adapted to training abroad.
- This course provides a deeper knowledge on diesel engine combustion and depollution, diesel fuels, high-pressure injection systems, turbocharging, after treatment systems.
- Upon completion of the course, participants will be able to:
- understand the mechanisms of pollutants formation and the trade-off between emissions, performance, fuel consumption, durability, cold starting, drivability,
- know the evolution of Diesel combustion and exhaust gas recirculation systems and how to optimize them,
- know the main fuel properties required for a good engine behavior,
- know the evolution of fuel injection systems and turbocharger technologies,
- know the exhaust gas after-treatment systems and strategies used on current and future engine.
- No prerequisites for this course.
Ways and means
- Various interactive talks, adapted to the participants’ fields of activity.
Diesel combustion optimization 2.25 days
- Automotive industry in the world.
- Approaches net classifications to define and design a powertrain.
- How does a spark engine work?
- Engine to wheel: air-fuel mixture, burn the air-fuel mixture, transformation into mechanical energy in the wheels.
- Chemical reaction equation, stoichiometric air/fuel ratio, equivalence ratio, specific heat value.
- Composition of exhaust gas. Flammability limits, flame propagation in normal combustion. Pollutants formation mechanisms: particles, nitrogen oxide, carbon monoxide, unburnt hydrocarbons.
- Influence of tuning parameters: air-fuel ratio, fuel injection timing, fuel-air mixture efficiency, temperature, injection pressure.
- Optimization of swirl, bowl in the piston, spray-holes position and diameter. Fuel spray characteristics.
- New combustion process: homogeneous charge compression ignition (HCCI), advantages and drawbacks.
- Full load behavior and optimization, durability limits, thermo-mechanical constraints; cracks in the metal.
- Cylinder head design: valves, inlet pipes and swirl generation, variable swirl.
- Exhaust gas recirculation (EGR); physical effect on NOx reduction, NOx/particles trade-off, EGR cooling, with or without by-pass, high and low pressure EGR circuit, problems and solutions for heavy trucks.
- Cold starting and warm-up: critical compression ratio, trade-off between noise, smoke emissions, instability; glow-plug functioning and control strategy. Ceramic glow-plug.
Diesel fuels characteristics 0.25 day
- Ignition delay and self-ignition ability: cetane rating.
- Cold flow characteristics: cloud point, cold filter plugging point, pour point.
- Lubricating properties, HFrr test, sulfur content.
Injection systems 0.75 day
- Nozzle holes manufacturing and characterization: discharge coefficient, effective flow area, hydraulic flow. Hydroground conical holes.
- Classification of current cam-driven and common-rail systems. Comparison between unit-injector and common-rail systems.
- Evolution of high pressure pump, common-rail solenoid and piezo injectors.
- Temperature control in low pressure circuit.
Turbocharging 0.75 day
- Turbocharger thermo-dynamical principle and technology. Design, materials, lubrication.
- Compressor and turbine field.
- Compressor and turbine dimensioning to match a given engine.
- Waste-gate, variable geometry turbine, parallel or sequential dual turbocharger.
Exhaust gas after-treatment 1 day
- Evolution of emissions regulations for passenger cars and heavy trucks.
- Oxidation catalysts: structure, light-off temperature, conversion rate, ageing; diesel particulate filter (dPF): structure, trapping efficiency, regeneration with fuel additive (FBC: fuel born catalyst) or catalyzed filter (CdPF); regeneration strategy, fifth or seventh injector, influence on oil drain intervals.
- NOx trap: operating principle, efficiency, limits.
- Selective catalytic reduction (SCR) with urea: principle, installation on heavy trucks, advantages and drawbacks.