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Internal Combustion Engines Diesel Engines Tiago Farias Diesel injection, impacts on efficiency, emissions, power

Internal Combustion Engines Diesel Engines - ULisboa · Internal Combustion Engines Diesel Engines Tiago Farias Diesel injection, impacts on efficiency, emissions, power

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  • Internal Combustion EnginesDiesel Engines

    Tiago Farias

    Diesel injection, impacts on efficiency, emissions, power

  • CICLO A 4 TEMPOS

    Intake Compression Expansion ExhaustInjection

    Combustion

  • 3

    Combustion in DIESEL engines

    Combustion of a spray: Injection

    Dispersion/mixture with air

    Evaporation

    Auto-ignition

    Burn of fuel

    Needs TIME!

  • Effective work

    Real Diesel Cycle

    Lost work

  • What about the hid? Diesel

  • What about the hid? Diesel vs SI, same Rc

  • What about the hid? Diesel , fast engine

  • What about the hid? Diesel vs SI

  • 11

    Combustion in DIESEL engines

    Combustion of a spray: Injection

    Dispersion/mixture with air

    Evaporation

    Auto-ignition

    Burn of fuel

    Needs TIME!

  • Typical values

    Engine typeMax. Speed

    (rpm)Mean piston speed (m/s)

    Racing engine (Formula 1) 18 000 25

    Small engines (two-stroke) 20 000 19

    Motorcycle engines 13 500 19

    Car SI engines 7 500 20

    Car Diesel engines 5 000 15

    Truck Diesel engines 4 200 14

    Larger high-speed Diesel engines 2 200 13

    Medium high-speed engines (Diesel) 1 200 10

    Crosshead engines (two-stroke Diesel) 200 8

    Maximum rotational speed and mean piston speed (approx.) at rated revs of modern enginesTaken from :R. Van Basshuysen and F. Schfer (eds): Internal Combustion Engines: basics, components, systems and perspectives, SAE International, Warrendale, Pa.2004

  • 15

    Combustion in DIESEL engines

    PHYSICAL DELAY + CHEMICAL DELAY = IGNTION DELAY

  • 16

    REDUCE IGNTION DELAY:

    BETTER SPRAY, HIGHER PRESSURE OF INJECTION

    BETTER AIR FLOW IN THE ENGINE

    BETTER FUEL

  • 17

    Common - Rail

  • 18

    Common Rail HDi: Grupo PSA

  • 19

    Common Rail HDi: PSA

  • Medium engine, l = 15cm, bore = 12 cm Vc = 1,7 litre (bus)Ue = 12 m/sNmax= 12*60/2/0,15 = 2400 rpm

    Large engine, l = 35 cm, bore = 25 cm Vc = 17 litre (ship)Ue = m/s Nmax= 10*60/2/0,35 = 860 rpm

    Small engine, l = 7,7 cm, bore = 8,6 cm Vc = 0,45 litre (car)Ue = m/sNmax= 14*60/2/0,077 = 5400 rpm

  • SISTEMAS DE PROPULSO DIESEL EM PESADOS

    ANFITEATRO AM, 17H-18H30

    FRIDAY, 11 DECEMBER 2015

    Eng. Jos Manuel Meira Afonso

    gestor da HYDRAPLAN

    7 de dezembro 16:30 s 18:00; sala FA2

  • 23

    Combustion in DIESEL engines

    Combustion of a spray: Injection

    Dispersion/mixture with air

    Evaporation

    Auto-ignition

    Burn of fuel

    Needs TIME!

  • Swirl

  • SQUISH

  • Swirl

  • Quish and Swirl

  • 28

    Quish and Swirl

  • Squish & Swirl

    http://www.renault.pt/gama/veiculos-de-passageiros/scenic/novo-scenic/motorizacoes-energy/

    http://www.renault.pt/gama/veiculos-de-passageiros/scenic/novo-scenic/motorizacoes-energy/

  • Internal Combustion EnginesDiesel Engines

    Tiago Farias

    Diesel injection, impacts on efficiency, emissions, power

  • 32

    Combustion: Diesel engines

    Diesel combustion

    C10H18 + a (O2+3,76N2) -> 10 CO2 + yreH2O + zre N2+ a HC + b CO + c NOx (NO;NO2) + particles

    CO2 emissions ~ 3.17 kg CO2 /kgfuel

    - Particles

    - HC unburned

    - CO incomplete combustion

    - NOx N2 + O2 + high Temp.

  • 36

    Combustion in DIESEL engines

    Combustion of a spray: Injection

    Dispersion/mixture with air

    Evaporation

    Auto-ignition

    Burn of fuel

    Needs TIME!

  • Physical delay: dispersion, evaporation, mixture with air

    Chemical delay: Arrhenius term

    Cetane number: measures how fast combustion takes place.

  • 2. revoluo: sistema Common Rail

  • Componentes de sistemas common rail

    Bosch: 1,100 and 2,200 bar; Denso: 2500 bar; futuro: 3000 bar

  • Presso de injecoa caminho dos 3000 bar

  • Evoluo do n. de injeces por ciclo (FIAT MultiJet diesel technology)

    Injeco Diesel: cada vez mais complexa

  • Lambda in Diesel Engines

    Thermal limite vs smoke limit

  • Lambda in Diesel Engines Thermal limite vs smoke limit

    For same speed:If l decreases:

    - more fuel is injected- Be, pe increases- efficiency increases, - temperature increases, and increases more forsmall S/V (large engines)

    If l starts approaching one- difficulties in burning all fuel

  • Lambda in Diesel Engines Thermal limite vs smoke limit

    Minimum l depends on:- S/V- Turbocharging pressures- Engine cooling system- How you use the engine (constant load)- The engine materials

    For large engines, the thermal limit appears first (low S/V)

    For small engines, with high squish and swirl, the smoke limit is the limit

  • Typical valuesEffective mean pressure of modern enginesTaken from :R. Van Basshuysen and F. Schfer (eds): Internal Combustion Engines: basics, components, systems and perspectives, SAE International, Warrendale, Pa.2004

    Engine typeEffective Mean Pressure (bar)

    up to

    Motorcycle engines 12

    Racing engines (Formula 1) 16

    Car SI engines (without turbocharger) 13

    Car SI engines (with turbocharger) 17

    Truck Diesel engines (with turbocharger)

    22

    Car Diesel engines (with turbocharger)

    20

    Larger high-speed Diesel engines 30

    Medium-speed Diesel engines 25

    Crosshead engines (two-stroke Diesel)

    15

  • Internal Combustion EnginesDiesel Engines

    Tiago Farias

    Engine Maps

  • Engine efficiency map

    53

  • Internal Combustion EnginesDiesel Engines

    Tiago Farias

    emissions

  • 55

    Controlo de emisses

    (HC, CO, NOx, PM)

    NEDC ciclo de velocidade Europeu

    0

    25

    50

    75

    100

    125

    0 100 200 300 400 500 600 700 800 900 1000 1100 1200

    t (s)

    v (

    km

    /h) ECE

    EUDC

  • Ciclo standard de homologao NEDC

    www.dieselnet.com (g/km)

    Normas EURO Diesel e gasolina

  • PM e Nox.. Uma dor de cabea!

  • 58

    Pollutants in Diesel Engines

    EGR (Exhaust gas recirculation)

    Particle filters

    NOx traps /SCR

    CO and HC oxidation catalytic converters

    Particles (PM)

    HC, CO,

    NOx CO2

    Control combustion or

  • 59

    Emissions: Diesel engines

    Diesel combustion

    C12H23 + a (O2+3,76N2) -> 12 CO2 + yreH2O + zre N2+ a HC + b CO + c NOx (NO;NO2) + particles

    CO2 emissions ~ 3.16 kg CO2 /kgfuel

    - Particles

    - HC unburned

    - CO incomplete combustion

    - NOx N2 + O2 + high Temp.

  • EGR Exhaust Gas Recirculation

  • EGR Exhaust Gas Recirculation

  • 65

    Pollutants in Diesel Engines

    EGR (Exhaust gas recirculation)

    Particle filters

    NOx traps

    CO and HC oxidation catalytic converters

    Particles (PM)

    HC, CO,

    NOx CO2

  • 66

    Particle filters

  • 67

  • 68

    Filtro de partculas (FAP - Peugeot)

  • SCR Selective Catalytic Reduction

  • DPF + SCR

    72

  • SCR Selective Catalytic Reduction

  • Internal Combustion EnginesDiesel Engines

    Tiago Farias

    Diesel injection, impacts on efficiency, emissions, power