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

3

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

4

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

percharged Thermal Management System

ard reformer for the Jaguar AJV6 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.