Transcript HCCI - IQSoft Software Consultants

HCCI – Diagnostics and Control
Prof. Mohamed Iqbal P
Mech. Engg. Dept,
TKMCE
Outline
•
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Current engines
HCCI in general
HCCI in Lund, some results
Production
Normal SI engine fuel consumption
Introduction
SI engine - part load improvement
100%
99%
98%
Catalyst
Efficiency
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


0.8
1.0
1.5
2.0
2.5
5.0
HCCI vs. GDI and CAI
Diesel Engine (CI)
•Large problems with emissions of NOx and PM
•High fuel efficiency (low CO2 emission)
HCCI Emissions
AutoTechnology
Oct. 2002, p 54
HCCI
USA 2007
PM
0,01
*
0,00
0
0,05
NOx
0,5
HCCI in Lund
HCCI activities in Lund
1.
2.
3.
4.
Basic engine studies
Laser diagnostics
Combustion modeling - Chemical kinetics
Closed loop combustion control
Experimental facilities –
single cylinder engines
(Volvo 1.6 liter)
Scania 2 liter
Volvo/Alvar 0.5 liter VCR
Old Hot bulb engine
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
Current optical engines
HCCI activities in Lund
1.
2.
3.
4.
Basic engine studies
Laser diagnostics
Combustion modeling - Chemical kinetics
Closed loop combustion control
Volvo TD100 engine
First VCR
system
Multifuel capability
Multifuel capability
Low NOx from HCCI mode
Gasoline & Diesel fuel
0.05
Specific NOx emissions [g/kWh]
0.045
100% Gas
65% Gas
40% Gas
20% Gas
0% Gas
=3.0
n=1000 rpm
0.04
0.035
0.03
0.025
0.02
0.015
0.01
0.005
0
10
15
20
Compression Ratio
25
With
Variable Compression Ratio, VCR,
the HCCI engine can use
ANY
liquid or gaseous fuel!
Basic engine tests…
The effect of turbulence on HCCI
combustion
Turbulence and geometry effects on HCCI
Experimental setup
Square bowl-in-piston
Disc
120
120
54
27
42
21
22
6
Piston body
Swirl Ratio=2.8
HS case
Swirl Ratio=2.0
LS case
Turbulence and geometry effects on HCCI
Turbulence
4
Disc, LS Head
Disc, HS Head
Square, LS Head
Square, HS Head
Centre Position
3.5
Turbulence [m/s]
3
2.5
2
1.5
2
1
u' 
0.5
0
-50
-40
-30
-20
2
 '2
 x  'y 




u u
2
-10
0
10 20
Crank Angle [CAD]
30
40
50
Turbulence and geometry effects on HCCI
Turbulence
8
Side Position
7
6
2
Disc, LS Head
Disc, HS Head
Square, LS Head
Square, HS Head
Turbulence [m/s]
Different
scale
5
4
3
2
1
0
-50
-40
-30
-20
-10
0
10 20
Crank Angle [CAD]
30
40
50
Turbulence and geometry effects on HCCI
Rate of Heat Release
800
Disc, LS Head
Disc, HS Head
Square, LS Head
Square, HS Head
SOC=-2 CAD
Rate of Heat Release [J/CAD]
700
600
500
400
300
200
100
0
-5
TDC
0
5
Crank Angle [ °ATDC]
10
HCCI activities in Lund
1.
2.
3.
4.
Basic engine studies
Laser diagnostics
Combustion modeling - Chemical kinetics
Closed loop combustion control
The influence of
Charge Heterogeneity on the HCCI
Combustion Process (?)
Fuel Distribution
Prior to Combustion
With port-injection
With mixing tank
Tracer PLIF after Auto-ignition
With port-injection
With mixing tank
OH PLIF Imaging
With port-injection
With mixing tank
High Speed Fuel LIF
Multi YAG-Laser System
Ordinary laser
t
Multiple pulse laser
t
• 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
MCP 1
Lens mount
Optional image
intensifier
or
Beam splitter
Iris
M
ir r
MCP 8
CCD 2-6
CCD 8
r
Frame store
Beam splitter optics
o
irr
Mass storage
M
CCD 1
High Speed Camera
• 8 independent CCD’s, 576x384 pixels
• Optional image intensifier  UV sensitive
10 ns temporal resolution
1 µs temporal resolution
Experimental setup
(Scania)
Cyl. Volume
Bore
Stroke
Comp. Ratio
Chamber design
Fuel
Lambda
1951 cm3
127 mm
154 mm
16:1
Pancake
Ethanol
3.85
Fuel Tracer PLIF
(resolved single-cycle)
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
W16mars_4
Conceptual model of HCCI
t
I   f (T (t ),Ignition
P(tat),T(t=1)
(t ), EGR%(t ), RR (Reactions
t )) dt at T(t=1), releasing
significant heat
0
Critical ignition temperature
Temperature
Ignition occurs when I reaches a critical value
T (x,t=0)
T (x,t=1)
Ignition at T (t=0)
Assuming homogeneous distributions of P, , EGR% and
RR: Wall
t
I   f (T (t )) dt
0
Arbitrary distance x
Conceptual model of HCCI
Reactions at T(t=1), releasing
t
significant heat
Temperature and
Air/fuel equivalence
ratio
I   f (T (t ),  (t )) dt
Ignition at T (t=1)
0
Critical ignition temperature
Effect of heterogeneous air/fuel ratio
T (x,t=1)
T (x,t=0)
Ignition at T (t=0)
Air/fuel equivalence
ratio
Wall
Arbitrary distance x
Ignition Temperature
Turbulence and geometry effects on HCCI
Suppression of hot and reactive zones
+2
+4
+2.5
+3
+4.5
+3.5
+5
+5.5
Transport of
heat & radicals
Single cycle fuel tracer LIF sequences
T-T
Bulk & boundary
layer interaction
Bulk
T
Piston
T+T
Boundary layer
Transport of
”cold” gases
HCCI activities in Lund
1.
2.
3.
4.
Basic engine studies
Laser diagnostics
Combustion modeling - Chemical kinetics
Closed loop combustion control
The 6-cylinder HCCI Engine
Closed loop combustion control,
CLCC
HEATERS
Inlet
Conditions
(pin,Tin)
NI PCI 6054
n-heptane
i-octane
Pressure
Traces
WaveBook
516
Injector
Actuator
User
Inputs
PC
Status
Calculation
PID
Controllers
Cylinder Pressure [Pa]
Control Parameters
6
15
x 10
Max dp/dCA
Max Pressure
10
Controlled
 CA50
5
0
-40
-20
0
20
40
60
80
Heat Release, Q [J]
dQ

dV
1
dp

p

V
dCA   1 dCA   1 dCA
3000
Constraints
 Peak pressure
 Peak dp/dCA
Heat Release
 Net heat release
2000
1000
0
-1000
-40
 Net IMEP:s
CA50
-20
0
20
40
Crank Angle [deg ATDC]
60
80
Combustion phasing=combustion duration
Combustion Timing
Ignition Diagram
Combustion phasing [CA 50]
15
10
5
0
40
50
60
70
80
-5
-10
Octane Number
S = d(CA50%) / d(Octane Number)
90
100
Sensitivity Estimation
S  f N N   fT Ti   f f m f  f O O   f  50 
Unstable Operation
35
30
Stable
Unstable
@ 3 bar IMEP
CA50 [°ATDC]
25
20
@ 4.5 bar IMEP
15
10
5
0
0
100
200
Cycle Index
300
Closed loop control switched off
400
Operating range
280 kW (380 hk)
16
14
12
HCCI Diesel
16
21 bar
280 310 kW
BMEP (bar)
10
8
6
4
2
0
1000
1200
1400
1600
Engine Speed (rpm)
1800
2000
Typical high load cycle
2
180
IMEP net
17.4 bar
1.8
160
IMEP gross 20.4 bar
1.6
Rate of Heat Release [kJ/CAD]
Cylinder Pressure [bar]
200
140
1.4
120
1.2
100
1
80
0.8
60
0.6
40
0.4
20
0.2
0
-30
-20
-10
0
10
Crank angle [CAD]
20
Load limited by
Peak Cylinder
Pressure at
200 bar and
maximum rate
of pressure at
30 bar/CAD
0
30
Animation Power
Fuel consumption and emissions
Engine speed
1200
rpm
BMEP
6.06
bar
Power
70.9
kW
Brake efficiency
42.8
%
0.024
g/kWh
HC
5.9
g/kWh
CO
4.4
g/kWh
NOx
And now to something
completely different:
HCCI in production 1890!
Akroyd Hot Bulb Engine 1890
•Low pressure early direct injection
•Fuel mix with residual gas and air
before combustion
•Combustion started as temperature
increase due to compression
Photo of model at the Science Museum, London UK
2-Stroke Hot Bulb Engine
Photo of drawing displayed at the Smithsonian Museum ,Washington, US
40
Efficiency
Efficiency
h [%]
b
30
20
DI
PC
SC
SI
HT
HB
10
0
0
2
4
6
8
BMEP [bar]
10
12
2002-01-0115
Hot Bulb Engine in Tractor
Cold Start of Hot Bulb Engine
Thank you for your attention!