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HCCI – Diagnostics and Control Prof. Bengt Johansson Div. of Combustion Engines, Dept. of Heat and Power Engineering,

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Presentation on theme: "HCCI – Diagnostics and Control Prof. Bengt Johansson Div. of Combustion Engines, Dept. of Heat and Power Engineering,"— Presentation transcript:

1 HCCI – Diagnostics and Control Prof. Bengt Johansson Div. of Combustion Engines, Dept. of Heat and Power Engineering, bengt.johansson@vok.lth.se www.vok.lth.se

2 Outline Current engines HCCI in general HCCI in Lund, some results Production

3 Normal SI engine fuel consumption

4 Introduction  100% 99% 98% Catalyst Efficiency SI engine - part load improvement Lean limit Stoichiometric premixed charge SI engine - Low part load efficiency + Low emissions with 3-way catalyst Lean burn premixed charge SI engine + Reduced pumping work  improved part load efficiency - Increased HC and NOx Stratified charge SI engine - GDI + Removed pumping work  much improved part load efficiency - Large problem with NOx and PM HCCI + Removed pumping work  much improved part load efficiency + Shorter combustion period  improved overall efficiency - Engine control problem 0.81.01.5 2.02.55.0

5 HCCI vs. GDI and CAI

6 Diesel Engine (CI) Large problems with emissions of NOx and PM High fuel efficiency (low CO2 emission)

7 HCCI Emissions HCCI 0,01 0,50 0,00 NOx PM * 0,05 USA 2007 AutoTechnology Oct. 2002, p 54

8 HCCI in Lund

9 HCCI activities in Lund 1.Basic engine studies 2.Laser diagnostics 3.Combustion modeling - Chemical kinetics 4.Closed loop combustion control

10 Experimental facilities – single cylinder engines (Volvo 1.6 liter) Scania 2 liter Volvo/Alvar 0.5 liter VCR Old Hot bulb engine

11 Multicylinder engines for HCCI control Scania 12 liter 6 cylinder dual fuel Volvo 12 liter 6 cylinder VGT Volvo 3 liter 6 cylinder VVT Saab 1.6 liter 5 cylinder VCR/FTM

12 Current optical engines

13 HCCI activities in Lund 1.Basic engine studies 2.Laser diagnostics 3.Combustion modeling - Chemical kinetics 4.Closed loop combustion control

14 Volvo TD100 engine

15 First VCR system

16 Multifuel capability

17

18 Low NOx from HCCI mode

19 With Variable Compression Ratio, VCR, the HCCI engine can use ANY liquid or gaseous fuel!

20 Basic engine tests…

21 The effect of turbulence on HCCI combustion

22 Turbulence and geometry effects on HCCI Experimental setup Square bowl-in-piston Disc Swirl Ratio=2.8 HS case Swirl Ratio=2.0 LS case

23 Turbulence and geometry effects on HCCI -50-40-30-20-1001020304050 0 0.5 1 1.5 2 2.5 3 3.5 4 Crank Angle [CAD] Turbulence [m/s] Centre Position Disc, LS Head Disc, HS Head Square, LS Head Square, HS Head Turbulence

24 Turbulence and geometry effects on HCCI -50-40-30-20-1001020304050 0 1 2 3 4 5 6 7 8 Crank Angle [CAD] Turbulence [m/s] Side Position Disc, LS Head Disc, HS Head Square, LS Head Square, HS Head Turbulence Different scale

25 Turbulence and geometry effects on HCCI -50510 0 100 200 300 400 500 600 700 800 Crank Angle [ ° ATDC] Rate of Heat Release [J/CAD] SOC=-2 CAD TDC Disc, LS Head Disc, HS Head Square, LS Head Square, HS Head Rate of Heat Release

26 HCCI activities in Lund 1.Basic engine studies 2.Laser diagnostics 3.Combustion modeling - Chemical kinetics 4.Closed loop combustion control

27 The influence of Charge Heterogeneity on the HCCI Combustion Process (?)

28 Fuel Distribution Prior to Combustion With port-injection With mixing tank

29 Tracer PLIF after Auto-ignition With port-injection With mixing tank

30 OH PLIF Imaging With port-injection With mixing tank

31 High Speed Fuel LIF

32 Multi YAG-Laser System t Ordinary laser t Multiple pulse laser Single/Double pulse operation 4 Pulses: Time separation (0-100ms) 8 Pulses: Time separation (6-145µs) Wavelengths: 532nm and 266nm Dye-laser for tuneable operation

33 High Speed Camera 8 independent CCD’s, 576x384 pixels10 ns temporal resolution 8 independent CCD’s, 576x384 pixels10 ns temporal resolution Optional image intensifier  UV sensitive 1 µs temporal resolution Optional image intensifier  UV sensitive 1 µs temporal resolution

34 Experimental setup (Scania) Cyl. Volume1951 cm 3 Bore127 mm Stroke154 mm Comp. Ratio16:1 Chamber designPancake FuelEthanol Lambda3.85

35 Fuel Tracer PLIF (resolved single-cycle) W16mars_4 2 ATDC 2.5 ATDC 3 ATDC 3.5 ATDC 4 ATDC 4.5 ATDC 5 ATDC 5.5 ATDC Fuel: ethanol Tracer: 10% acetone  3.85 Rc: 16:1

36 Fuel tracer PLIF from four cycles

37 Conceptual model of HCCI Ignition occurs when I reaches a critical value Assuming homogeneous distributions of P,, EGR% and RR:

38 Conceptual model of HCCI Effect of heterogeneous air/fuel ratio

39 Ignition Temperature

40 Turbulence and geometry effects on HCCI Suppression of hot and reactive zones +2 +5.5 +2.5+3+3.5 +4+4.5+5 Single cycle fuel tracer LIF sequences

41 HCCI activities in Lund 1.Basic engine studies 2.Laser diagnostics 3.Combustion modeling - Chemical kinetics 4.Closed loop combustion control

42 The 6-cylinder HCCI Engine

43 Closed loop combustion control, CLCC WaveBook 516 WaveBook 516 NI PCI 6054 Status Calculation PID Controllers HEATERS Injector Actuator Injector Actuator User Inputs PC Pressure Traces Inlet Conditions (p in,T in ) n-heptane i-octane

44 Control Parameters -40-20020406080 0 5 10 15 x 10 6 Max Pressure Max dp/dCA Cylinder Pressure [Pa] -40-20020406080 -1000 0 1000 2000 3000 CA50 Heat Release Crank Angle [deg ATDC] Heat Release, Q [J] Controlled  CA50  Net IMEP:s Constraints  Peak pressure  Peak dp/dCA  Net heat release

45 Combustion phasing=combustion duration

46 Combustion Timing Octane Number -5 0 5 10 15 405060708090100 Combustion phasing [CA 50] S = d(CA50%) / d(Octane Number)

47 Sensitivity Estimation

48 Unstable Operation 0100200300400 0 5 10 15 20 25 30 35 Cycle Index CA50 [°ATDC] Stable Unstable @ 3 bar IMEP @ 4.5 bar IMEP Closed loop control switched off

49 Operating range 280 kW (380 hk) HCCI Diesel 16 21 bar 280310 kW HCCI Diesel 16 21 bar 280310 kW

50 Typical high load cycle Load limited by Peak Cylinder Pressure at 200 bar and maximum rate of pressure at 30 bar/CAD IMEP net17.4 bar IMEP gross 20.4 bar Animation Power

51 Fuel consumption and emissions Engine speed1200rpm BMEP6.06bar Power70.9kW Brake efficiency42.8% NOx0.024g/kWh HC5.9g/kWh CO4.4g/kWh

52 And now to something completely different:

53 HCCI in production 1890!

54 Akroyd Hot Bulb Engine 1890 Photo of model at the Science Museum, London UK Low pressure early direct injection Fuel mix with residual gas and air before combustion Combustion started as temperature increase due to compression

55 2-Stroke Hot Bulb Engine Photo of drawing displayed at the Smithsonian Museum,Washington, US

56 Efficiency BMEP [bar]  b [%] DI PC SC SI HT HB Efficiency 2002-01-0115

57 Hot Bulb Engine in Tractor

58 Cold Start of Hot Bulb Engine

59 Thank you for your attention!


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