CONVENTIONAL FUELS Carlos Sousa AGENEAL, Local Energy Management Agency of Almada

1. CONVENTIONAL FUELSCarlos SousaAGENEAL, Local Energy Management Agency of Almada

2. DIESEL AND PETROL ENGINES 4 Stroke Cycle Main components Auxiliary Systems

3. INTAKE Air enters the combustion chamber DIESEL 4 Stroke Cycle

4. COMPRESSION With all the valves closed, the piston goes up, compressing the air inside the cylinder Increase in air temperature and pressure DIESEL 4 Stroke Cycle

5. INJECTION The fuel is injected into the cylinder at high pressure, after the compression of the air DIESEL 4 Stroke Cycle

6. EXPANSION The fuel inflames when it contacts with the hot air The mechanical delivered the engine is now generated DIESEL 4 Stroke Cycle

7. EXHAUST After the combustion, the hot gases leave the cylinder through the exhaust valve(s) DIESEL 4 Stroke Cycle

8. INTAKE COMPRESSION INJECTION EXPANSION EXHAUST DIESEL 4 Stroke Cycle COMBUSTÃO

9. Compression Ratio =

10. MAIN COMPONENTS OF THE ENGINE

11. MAIN COMPONENTS OF THE ENGINE • Piston – Transmits the movement to the rod • Connecting Rod – Transmits the movement to the cranshaft • Crankshaft – Transforms the alternative movement in circular movement

15. MAIN AUXILIARY SYSTEMS Distribution (opening / closing of the valves) Cooling system (prevents components from overheating) Lubrication (reduces sheer, washes components, etc.) Fuel (fuel intake)

16. DISTRIBUTION Double OverHead Cam, DOHC Lateral Cam

17. DISTRIBUTION

18. COOLING SYSTEMS Objectives • Cool engine components: • keep the engine at a suitable operating temperature (i.e. prevent the melting of components) • keep the physical and chemical proprieties of the lubricating oil (can deteriorate with exessive temperature) • Provide heat to acclimatize the interior of the vehicle • Improve cold start

19. COOLING SYSTEMS Water pump Thermostat Radiator Fan Heating system

20. LUBRICATING SYSTEM The function of the engine oil is much more than lubricating. The oil must also have: • High detergent and dispersant power • High anti-oxidation power • Good cooling capacity (contributes to engine cooling) • Good capacity to neutralize acids • Maintain its with temperature change (cold and hot)

21. LUBRICATING SYSTEM

22. FUEL SYSTEM Objective: • Introduce fuel in the engine, that will mix with the hot air inside the cylinder, evaporate, auto-inflame and burn

23. FUEL SYSTEM • Indirect injection • DIRECT INJECTION • Direct injection in the cylinders • Higher injection pressures • More expensive and demanding technology • Multiple jet injectors

24. DIRECT INJECTION vs. INDIRECT INJECTION

25. DIRECT INJECTION vs. INDIRECT INJECTION

26. DIRECT INJECTION

27. DIRECT INJECTION Squish and Swirl

28. TYPES OF INJECTION SYSTEMS • Radial and in-line pump • Injector-pump • Common Rail

29. TYPES OF INJECTION SYSTEMS • In-line pump 600...700 bar  1 000 bar at the tip of the injector

30. TYPES OF INJECTION SYSTEMS • Radial pump 1 000 to 1 500 bar at the tip of the injector

31. INJECTION SYSTEMS Injector Pump 2000 bar • Advantages • No high-pressure fuel lines • Higher injection pressures • Lower fuel consumption • Better torque and power at low engine speeds

32. INJECTION SYSTEMS Pressão máx. 1350 – 1500 bar Common-Rail 1 800  2 000 bar Advantages • Better injection control • Reduction of noise and vibration • Good fuel consumption • Good torque and power • Reduction of pollutant emissions

33. INTAKE IN PETROL ENGINES • A petrol engine can admit: • A mixture of air and fuel • Air, with the fuel being injected directly into the cylinder – Direct Injection Engines Source: Total

34. TURBOCHARGING • Objective: Increase the power/weight ratio • A compressor increases the density of the air before being admitted to the cylinders • Disadvantages (relative to atmospheric engines - “non-turbo”): • Higher complexity and cost • Higher physical and thermal strains on the engine • Advantages: • More torque and power • Better fuel consumption

35. TURBOCHARGING

36. TURBOCHARGING

37. TURBOCHARGING Variable geometry • More torque over all engine speed range • Better fuel consumption • More power

38. TURBOCHARGING • INTERCOOLER • Objective: Increase the power/weight ratio • Cools the air after the compression, before admitting it to the cylinders: • Higher mass of air inside the cylinders • More fuel • More torque • More power

39. POLLUTANTS FORMATION AND CONTROL • Combustion in Diesel engines is characterised by a high concentration of fuel droplets (poor atomization/vaporization of the fuel). • Main pollutants: • Particulate Matter (PM) • Unburned Hydrocarbons, HC • Carbon Monoxide, CO • Nitrogen Oxides, NOx

40. POLLUTANTS FORMATION AND CONTROL • Emissions control: • Exhaust Gas Recirculation, EGR • Particulate Filters • Catalytic Converters

41. POLLUTANTS FORMATION AND CONTROL • Emissions control • Diesel: • Exhaust Gas Recirculation, EGR (prevents the formation of NOx) • Particulate Filters, active and passive (PM) • Oxidation Catalytic Converters (HC and CO) • Selective Catalytic Reduction, SCR (NOx into N2 and H2O) • Petrol: • 3-way Catalytic Converters • Oxidation Catalysts (CO and HC into CO2 and H2O) • Reduction Catalysts (NO into N2 and O2)

42. Fuel Quality, Diesel: • Diesel is cetane derived (C10H22) • Cetane Number: Indicates the higher or lower capacity of the fuel to auto-ignite ( lower delay to auto ignition) • 15: Low capacity to auto-ignite: isocetane • 100: High capacity to auto-ignite: cetane • Minimum cetane number demanded: 51 • Sulphur content: Less than 50 ppm  Low sulphur fuel • Eliminate emissions of sulphur dioxide (SO2) • Reduce PM emissions • Less than 10 pmm: Sulphur free fuel (From 2009)

44. POLLUTANTS FORMATION AND CONTROL

45. Diesel Passenger vehicles  2.5t (values in g/km) EUROPEAN EMISSIONS STANDARDS

46. ENERGY EFFICIENCY • TORQUE • Energy generated in one revolution of the engine, resulting from the combustion of the fuel [kg.m or N.m]. • 1 kg.m=9.8 N.m • The higher the torque, the more efficient is the engine for a given engine speed. • POWER • Energy generated per unit of time [W or CV]. • 1kW = 1,36 CV • 1 CV = 0,736 kW

47. ENERGY EFFICIENCY • Torque curve • Shows the torque distribution along the entire engine speed range, at full engine charge (full throttle). • Should be as flat as possible, which means good engine response at all engine speeds. • RPM x N.m (or kg.m)

48. ENERGY EFFICIENCY • Power curve • Shows the power distribution along the entire engine speed range, at full engine charge (full throttle). • RPM x kW (or CV)

49. ENERGY EFFICIENCY • CO2 emissions per litre: Petrol a little lower Diesel • CO2 emissions per km: Diesel uses less fuel... …emits less CO2 • Energy efficiency is a function of the compression ratio • Diesel engines use variable fuel to air ratios • Petrol engines use a constant air to fuel ratio (stoichiometric: 14.7 to 1), no matter what the speed and load are • Diesel engines have an unthrottled intake and the air to fuel ratio at idle speed can go as low as 100 to 1, thus giving a much greater partial load fuel efficiency than petrol engines

50. Petrol engines Theoretical engine efficiency Diesel engines Compression ratio ENERGY EFFICIENCY