3 days MOT/PRESTAP-E
- Engineers and technicians in charge of development activities (calibration or design of functions, systems or components) having an impact on full load performances.
- This course provides a deeper knowledge and competencies on vehicle performances with spark ignition and diesel engines.
- Upon completion of the course, participants will be able to understand:
- the fundamentals of the combustion physics, filling and injection, in order to improve efficiencies and performance,
- how the gasoline and diesel fuel characteristics affect the engine behavior,
- the strategies of engine management and its impact on engine performance,
- the link between customer attributes and design & development activities.
- IC Engine Fundamentals.
Introduction 0.25 day
- V cycle.
- Torque (instantaneous, average), power, notion of load, use curve, cycle engine work, indicated mean effective pressure (IMEP), break mean effective pressure (BMEP), friction mean pressure (FMEP), mean piston speed, thermal load and specific power.
- Overall efficiency, combustion efficiency, thermodynamic efficiency, cycle efficiency and mechanical efficiency. Filling and volumetric efficiency.
Performances: combustion & limits 1 day
- Fundamentals of combustion
- Combustion: combustion equation, determining the stoichiometric quantity and the air/fuel ratio, calorific value. Pollutants formation, flammability limit, auto-ignition delay.
- Aerodynamic air/fuel in combustion chamber vs swirl & tumble.
- Comparison between gasoline and Diesel engines: combustion process (load control, preparing the air-fuel mixture, initiation, expansion, pollutants formation, exhaust gas recirculation (EGR), vibrations and noise origins), full load performance limits (knocking, mechanics, thermo-mechanics, exhaust temperatures), in-use efficiency (downsizing, downspeeding).
- Fuel features: cetane number (diesel), octane number (gasoline).
- Full load limits linked to the engine architecture: knocking, maximum cylinder pressure, exhaust temperature, heat flow for the holding of cylinder head, piston, …, compressor output temperature, blow by and dilution.
- Full load limits linked to the visual consequences of the combustion (black smoke in diesel, …).
- Full load limits linked to thermo mechanics constraints of the components: injection system (injection pressure and temperature (HP pump) and nozzle temperature), turbocompressor.
Fuel injection system 0.25 day
- Diesel: injector-pump, common rail (solenoid, piezo with pressure amplification, …). Evolutions.
- Gasoline: fuel injection systems and evolutions.
Characterization - Breathing & supercharging 0.5 day
- Performances: potential of the different technologies, parameters affecting the performances.
- Admission and exhaust back pressure losses.
- Breathing: volumetric efficiency, timing, acoustic inlet (Kadenacy effect, ¼ wave, …), and exhaust (3Y manifolds, separate exhaust lines, …) optimization.
- Link between breathing and performances.
- Compromise between Cf β/swirl (diesel).
- Variable distribution systems.
- Supercharging: supercharging types, turbocharger operation and technology, mapping (characteristic fields), adaptation to engine, trade-off to carry out.
- Operating of turbochargers: geometrical characteristics, flow control, cooling energy.
- Map pressure-flow of the compressor and operating limits. Characteristics of turbine, saturation.
- Turbocharger parts technology: materials, lubrication, reliability, geometry fixed /variable, twin scroll, double/triple supercharging.
- Adaptation of a turbocharger on an engine: choice of the compressor and the turbine according to the characteristics and performance of the engine.
Introduction to engine management system 0.75 day
- Introduction to engine management (torque structure).
- Stabilized conditions: full load calibration.
- Powertrain protections: gearbox, transmission; mechanical resistance of the engine and components (turbocharger over speed, dilution, etc.); thermal resistance of the engine and components (calibration protections to manage temperature of fuel, water, air, etc.).
- Diesel: transient conditions (smoke mapping, overboost and overfueling, calibrations of the turbocharger), exotic conditions (hot/altitude).
- Gasoline (knocking): definition/consequences of main parameters, calibrations (knocking limit, curative and preventive calibration).
- Dispersions. Robustness.
- Full load homologation and conformity of production.
Performances on vehicle 0.25 day
- Vehicle maximum speed.
- Effect of drivability calibration on the subjective perception of the client.
- Effect of transmission.
- Validation plan.