iav, chemnitz, 2011
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Excellence in Automotive R&D
Engine Tests with Ambixtra Ignition SystemComparision of Ambixtra Ignition System with a Coil Ignitions System with Single Spark Dr. Ralf Tröger, Dr.-Ing. Thomas Emmrich, Sascha Nicklitzsch
Chemnitz, 26th of June till 1st of July 2011
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 2
Objectives
• performing of engine tests based on the prior tests on the flow chamber
• comparison the performance of the Ambixtra ignition system with a coil ignition system (single spark) in different operation conditions
• further optimisation of the setup of Ambixtra ignition system • conditions:
• EGR variation in low load state
• variation of A/F-ratio at 2000 rpm/2 bar
• offset variation between EOI and ignition angle in stratified mode
• cold start
• ignition system parameter study (examples)
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 3
Test Engine
Technical parameters:
• 4 – Cylinder gasoline DI-inline engine
• displacement: 1995 cm³
• compression ratio: 12
• stratified and homogeneous operation
• cooled high pressure EGR (max EGR)
• turbocharger with waste gate and intercooler
• variable camshaft phasing for intake and outlet side
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 4
Test Bench Equipment and Measurements
• test bench automatisation: AVL PUMA open 1.4
• emission analyser: Horiba MEXA 7000
• indication system: AVL indiset 620 (high and low pressure indication)
• Knock indication system: IAV KIS
• ECU access: ETAS ES 1000 + INCA
• optical access: AVL VisioScope
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 5
IAV Test Benchconfiguration
engine
air box
intercoolerEGR pipe
intake manifold
wire connector
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 6
IAV Test Benchconfiguration
fuel meter
pressure signal amplifier
Dyno
ETAS ES 1000
light unit optical access
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 7
Ambixtra Spark Ignition SystemEGR variation in low load state
• Ambixtra system delivers similar results like the coil ignition system up to 10 % EGR-rate
• higher EGR-rates → higher inertgas-ratio → increase of COV (more unstable operation)
• in case of coil ignition particular cylinders start to deviate with higher EGR
• with Ambixtra-system more stable operation cycle-to-cycle and cylinder-to-cylinder at EGR > 10%
homogeneous mode, n = 2000 rpm, BMEP = 2 bar
BSFC
250
275
300
325
350
375
400
425
450
g/kW
h50
0
EGR-rate0 2 4 6 8 10 12 14 16 % 20
coil ignition, single spark Ambixtra
A/F-
ratio
(λBS
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
-5.
0
coef
ficie
nt o
f var
iatio
n (C
OV)
010
2030
4050
6070
80%
100
COV
A/F
p mi_
GE
-1.5
-1.3
-1.1
-0.9
-0.7
-0.5
-0.3
-0.1
0.1
bar
0.5
pmi_GE
BSFC
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 8
Ambixtra Spark Ignition SystemVariation of A/F-ratio (2000 rpm/ BMEP = 2 bar)
• from A/F-ration 0.9 up to 1.3 there are no sifgnificant differences in operation between Ambixtra ignition system and coil ignition system
• with A/F-ratios higher than 1.3 the increase of engine roughness is less with the Ambixtra system
homogeneous mode, n = 2000 rpm, BMEP = 2 bar
BFSC
200
225
250
275
300
325
350
375
400
g/kW
h45
0
A/F-ratio (λ)0.8 0.9 1.0 1.1 1.2 1.3 1.4 - 1.6
coil ignition, single spark Ambixtra
A/F-
ratio
(λBS
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
-5.
0
coef
ficie
nt o
f var
iatio
n (C
OV)
010
2030
4050
6070
80%
100
C O V
A/F
p mi_
GE
-1.5
-1.3
-1.1
-0.9
-0.7
-0.5
-0.3
-0.1
0.1
bar
0.5
pmi_GE
BSFC
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 9
Ambixtra Spark Ignition SystemOffset variation between EOI and ignition angle in stratified mode
• the offset between EOI and ignition angle is a very sensitive parameter in stratified mode
• with the Ambixtra system with the long spark duration, a quiet larger shift to later EOI‘s is possible
combustion system less sensitive to cyclic deviations (put injection on the secure side)
• potential for stratification using lateral injector
stratified mode, n = 2000 rpm, BMEP = 2 bar, pintake=1000 mbar
B SFC
25
027
53 0
032
535
037
540
042
545
0g/
kWh
500
EOI2180 185 190 195 200 °CA 210
coil ignition, single spark Ambixtra
A/F-
ratio
(λBS
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3 .5
4.0
-5.
0
coef
ficie
nt o
f var
iatio
n (C
OV)
010
2030
4050
6070
80%
100
COV
A/F
αQ
50
-30
-24
-18
-12
- 60
612
18° a
TDC
30
αQ50
BSFC
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 10
Ambixtra Spark Ignition SystemCold start
• slightly lower HC-emission → better combustion
• higher exhaust temperature upstream turbo → light off temperature of catalyst could be reached earlier
• higher implemented ignition energy and longer spark duration lead to more stable inflammation
• for more detailed information, start tests with fast exhaust gas analysis systems (specially HC) are recommended
• potential for more retarded ignition timing not tested
homogeneous, n = 0 - > 1100 min-1, pme = 0 ->2 bar
Time0 10 20 30 40 50 60 70 80 s 100
HC
015
0030
0045
0060
0075
00pp
m10
500
exha
ust t
empe
ratu
re (T
exh_
uT)
050
100
150
200
250
°C35
0
Ambixtra1 coil ignition, single spark Ambixtra2
© IAV GmbH · 07/2011 · TE1 · MO-A1 · Results_engine_Ambixtra.ppt 11
Ambixtra Spark Ignition SystemIgnition system parameter study (examples)
• with longer spark duration, engine roughness and BSFC decrease
• longer spark duration is an advantage for lean mixture inflammation
• on 8 ms the DC is off –effect to be shown later
homogeneous mode, n = 2000 rpm, BMEP = 2 bar, A/F-ratio = 1,5
BSFC
250
270
290
310
330
350
370
390
410
g/kW
h45
0
spark duration0 1 2 3 4 5 6 ms 8
BSFC
A/F-
ratio
(λBS
)
0.0
0.4
0.8
1.2
1.6
2.0
2.4
2.8
3.2
-4.
0
coef
ficie
nt o
f var
iatio
n (C
OV)
010
2030
4050
6070
80%
100
COV
A/F
p mi_
GE
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
bar
-0.0
pmi_GE
DC on, at 8 ms DC offspark amount = 20
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