IAV, Chemnitz, 2011

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)


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


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 Test Benchconfiguration

engine

air box

intercoolerEGR pipe

intake manifold

wire connector


IAV Test Benchconfiguration

fuel meter

pressure signal amplifier

Dyno

ETAS ES 1000

light unit optical access


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


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


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


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


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


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


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

Excellence in Automotive R&D

Thank youDr. Ralf Tröger [email protected]

Dr.-Ing. Thomas [email protected]

Sascha [email protected]

IAV GmbHIngenieurgesellschaft Auto und Verkehr

IAV, Chemnitz, 2011

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