Download - Dieseline/multi-fuel Combustion
Dieseline/multi-fuel Combustionfor HCCI Engines
Hongming Xu & Miroslaw WyszynskiThe University of Birmingham
IEA-28th TLM, Heidelberg, August 13-16, 2006
2
Presentation Outline
Research background Present objectives Research engine setup Results and discussion Conclusions Future prospects
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CHARGE/CHASE Project Outline
partners: Jaguar Cars, Birmingham UniversityJohnson Matthey, MassSpec UK
Apr/02 Apr/04
CHARGE (Controlled Homogeneous Auto-ignition Reformed Gas Engine), 2 yrs DTI sponsored, Jag/total funding = £420/840Kconcluded 28/04/04 Facilitate natural gas HCCI using fuel reforming
Reviewed by UK EPSRC: “Tending to International Leading”
CHASE (Controlled Homogeneous Auto-ignition Supercharged Engine)3 yrs DTI sponsored, Jag/total funding = £720/1,539K)Kicked-off 28/04/04 Expand gasoline HCCI window
National Engineering Laboratory Race Technology
Apr/07
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Research Partnership
Project leader, engine and optical workProject leader, engine and optical work Reforming catalyst developmentReforming catalyst development
Engine and reforming experimentEngine and reforming experimentMS supportMS supportNELNEL
Race TechnologyRace Technology
ASE Next Generation (2004-2007)
Main objective – Extend the operating window of Gasoline HCCI using combination of boosting, exhaust gas fuel reforming, and total thermal management.
xtension by fuel reforming
Current HCCI
Extension by boosting
Lean-burn
Engine speed
Boosting
ThermalManagem’t
Reforming Aftertreatm’t
e single cylinder research engine
27.7 / 24.1 mm 3 mm for NVO(8 mm standard)
Valve diametersand lift
liquid port-injected, injection at 3 bar (gauge)
Fuelling type
10.4 for cold NVO(15.0 for heated intake standard valve events)
Geometric Compression Ratio
165Connecting Rod Length (mm)
80 x 88.9Bore x Stroke (mm)
4 - stroke, single cylinder, 4 valve, pent-roof head
Engine type(Medusa base)
ncept of CHARGE/CHASE (2002-2007)
formed natural gas (test data) Modelling of the effect of fuel property
Main objective - Evaluate the effect of fuel composition and control of engine parameters on the auto-ignition process of natural gas in automotive engines
emissions for HCCI – fuel reforming (NG)
Hydrogen enriched HCCI has a lower NOx emission level and load limit than normal HCCI, with additional effect from reforming
0
3
6
9
0 180 360 540 720
Crank angle (°CA)
Valv
e lif
t (m
m)
StandardCAI J1R
Exhaust VCT
Intake VCT
rld 1st dual cam profile switching engine
le-by-cycle & cylinder-to-cylinder variations
Witho t reformed gas
Cylinder 1Cylinder 6
With on line reformed gas
Cylinder 1Cylinder 6
eseline’ research objectives
Gasoline, diesel and a variety of alternative fuels are all ossible fuels for HCCI combustion but none of them as a ngle fuel has proved to be able to enable a satisfactory perating window.
Gasoline and diesel fuels, the most widely supplied ain fuels, have indeed very different but complimentary roperties. Gasoline, which has high volatility but low nitability, is generally produced as a high octane number el.
The Diesel fuel, on the other hand, has a high cetaneumber with larger carbon content and heavier molecular eight with low volatility, is better suited to auto-ignition ut often requires a lower compression ratio.
esent research
to investigate the HCCI combustion behaviour of the mixtures of gasoline and diesel as the two fuels with opposite but complementary properties.
to investigate whether the two fuels can provide a compromise HCCI combustion where the ignitability of charge is improved
to restrain violent knocking so as to operate the engine in a controllable HCCI combustion mode under a moderate compression ratio
st Test matrix
√√√√√NVO(CR=10.4)
√√√Intake heating(CR=15.0)
50:5080:2090:1095:5100:0
Fuel Composition Gasoline : Diesel (by mass)
D50D20D10D5D0Fuel Designation
-ratio boundary with EGR trapping
1.5
1.8
2.1
2.4
2.7
3
0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5Excess Air Ratio λ
IME
P (b
ar)
D0D5D20D50
Misfiring boundary
D0 (pure gasoline), D5, D10 and D50, in NVO HCCI mode, CR=10.4, 1500 rpm, unheated intake, low lift cams, NVO = -170 deg.
provement in combustion stability
0123456789
10
1 1.5 2 2.5 3
IMEP (bar)
CO
V o
f IM
EP
%
D0D10D50
rough runningsmooth running
D0 (pure gasoline), D10 and D50 when engine worked with unheated NVO HCCI mode, CR= 10.4, 1500 rpm.
lve timing – case study
0 360 720
Crank Angle Degrees (CAD)
IVOEVO EVC IVC
Cylinder Pressure Trace
MOP MOP
Negative Valve Overlap
70 70 70 70
Valve timing used in HCCI engine operated in NVO (negative valve overlap) mode.
“0” crank angle degrees indicates TDC in the compression / combustion revolution.
All IV/EV timings are symmetrical w.r.t. TDC
-200170170Case 5
-180160160Case 4
-160150150Case 3
-140140140Case 2
-120130130Case 1
Valve Overlap(CAD)
Exhaust valve MOP
(CAD bTDC)
Inlet valve MOP
(CAD aTDC)
Conditions
reasing diesel content, = const, NVO = const
D0, D10, D20 fuels Case3NVO = -160 CAD1500 rpm, lambda = 1.2
0
5
10
15
20
25
30
35
-40 -30 -20 -10 0 10 20 30 40Crank Angle Degree (CAD)
y(
) D20
D10
D0
Case3 λ=1.2
tion advances with increased load and diesel content
-10-8-6-4-202468
1 1.5 2 2.5 3 3.5IMEP (bar)
5% b
urn
poin
t (C
AD) D20
D10D0
Case3
-10-8-6-4-202468
1 1.5 2 2.5 3 3.5IMEP (bar)
5% b
urn
poin
t (C
AD
) D20D10D0
Case3
EP boundary with Variable diesel content
combustion stability for pure gasoline D0 is poor, particularly at lower loads, this is also due to retarded combustion phasing
D20 offers a very respectable and acceptable COV below 5% over practically its whole range of IMEP
1 1.5 2 2.5 3 3.5IMEP (bar)
DOD10D20
Rough Runing
Smooth Runing
Case 3
omparison of load boundary
with D20 fuel, a substantial increase in the upper limit of engine load and a wide ean limit of lambda was achieved compared with D0 fuel.
diesel fuel addition at the same Case of NVO also enables richer mixtures and higher loads with sustainable combustion
8 1 1.2 1.4 1.6 1.8 2 2.2
Lambda
Case2Case3Case4-3
-3
-3
-21 3
0
0
3
0
3
D0 fuel (gasoline)
1.5
2
2.5
3
3.5
0.8 1 1.2 1.4 1.6 1.8 2 2.2
Lambda
IME
P (b
ar)
Case1Case2Case3Case4Case5
-3 -2
-3
-3
-3
-3
032
-2 0 13
0
1
30 3
02 3
D20 fuel
omparison of emissions
0
0.1
0.2
0.3
0.4
1 1.5 2 2.5 3 3.5IMEP (bar)
D20D50
0
100
200
300
400
500
600
1 1.5 2 2.5 3 3.5IMEP (bar)
HC
Em
issi
on (p
pm)
D20D50
0
10
20
30
40
50
60
1 1.5 2 2.5 3 3.5IMEP (bar)
D20D50
1500 rpm, intake temperature 380 K, intake pressure = 0.1 MPa (abs), CR = 15.0, standard camshaft with positive valve overlap
mparison of emissions with varied and load
0
1
2
3
4
1.5 2 2.5 3IMEP (bar)
CO
Em
issi
on (%
) D0D5D20
0
20
40
60
80
100
1 5 2 2 5 3
(pp
) D0D5D20
1500 rpm, unheated intake, low lift cams, NVO = -170 deg, varied
0
200
400
600
800
1000
1.5 2 2.5 3IMEP (bar)
HC
Em
issi
on (p
pm)
D0D5D20
Ox variation when 5% burn kept at TDC
Case 5 has large NVO, more residual gases in cylinder, higher in-cylinder temperature during the next consecutive cycle. Over-advanced combustion phasing may also be partially responsible for higher NOx
0
20
40
60
80
1.5 2 2.5 3 3.5IMEP (bar)
NO
x E
mis
sion
(PP
M)
D0D20
Case1
Case2
Case3Case4
Case5
Case2
Case3Case4
NVO
mparison of fuel consumption
280
284
288
292
296
300
0.8 1 1.2 1.4 1.6 1.8 2
Lambda
SFC
(g/iK
Wh)
D20D0
1500 rpm, 5% burn at TDC, stable combustion
mmary and conclusions he blended fuel namely ‘dieseline’ makes compromised and optimal r to the desired ignition quality, which reduces the dependence of CI on EGR trapping or intake heating.
r ‘dieseline’ HCCI, the required intake temperature heating can be ered by at least 10 degrees compared with pure gasoline operation. h diesel addition, appropriate engine conditions can be achieved for oline HCCI with EGR trapping for a wide range of CR.
e HCCI operating region for the unheated NVO can be significantly ended into lower IMEP values and the audible knocking is restrained to
highest values of at high load boundary for the highest mixture peratures. The resulting effects make it possible to reduce the NVO rval required for stable combustion.
e possible scale of NVO was extended by up to 40 CAD, the lean limit of bda can almost reach up to 2.0 when engine is operated with a moderate pression ratio (10.4). However this might cause a CO emission penalty at leanest limit due to lower combustion temperature
mmary and conclusions
he indicated specific fuel consumption and CO emissions crease due to decreased pumping losses of recompression and her combustion efficiency.
missions of HC and NOx show an interesting improvement mpared with gasoline HCCI with optimized engine operating nditions.
A substantial increase in the upper limit of load range will behieved without intake heating because of higher volumetric ciency resulting from smaller NVO and the presence of less idual gases in cylinder. However this can result in potentially her NOx emissions due to the lower dilution amount present and her combustion temperature.
Pretreatment + New management
“Low Temperature”Combustion
“Low Temperature”Combustion
Conventional compression engines
Conventional spark-ignition Engines
soline and Diesel Engine Technologies are emerging
lti-fuel injection system – the future of new engines?
A computer controlled our printer can printourful pictures using riginal coloured inks –
f we have 3 different type of ls, why cant’ a CPU controlled l injection system supply equired fuel ‘colour’ (property) ‘printing a beautiful picture’ – for optimised engine
eration at varied conditions?
Simply, a multi-channel fuel nozzle is required at gas tions to supply the fuels as for printer cartridges!
cknowledgements
The authors would like to acknowledge the assistance and cooperation of the colleagues and coworkers in the Future Power Systems Group at the University of Birmingham, especially Dr S Zhong as academic visitor. The support from Jaguar in relation to the present research work is also gratefully acknowledged.