Transcript engine - HAW Hamburg

Auto-Ignited Kernels during
Knocking Combustion
in a Spark-Ignition Engine
Okayama University
Nobuyuki KAWAHARA
Eiji TOMITA
Requirements of spark-ignition (SI) engine
- Lower fuel consumption
- Reduced emission of pollutants.
Higher thermal efficiencies
P ressu re, M P a
Engine knocking due to
higher compression ratio
4.0
Knocking cycle
3.0
2.0
1.0
0.0
320
StandardEnd-gas
cycle
340
360
380
Crank angle, deg.
400
Okayama University
Background
Valve-stopper
Valve
Thermocouple
In
Heater
Solenoid
Valve-closure
signal
Pressure transducer
Spark electrode
Water
Out
Elongated
Bore: 78 mm
piston
Mixture
tank
Crank angle pulse
TDC signal
Stroke: 85 mm
Compression ratio: 9.02
Engine speed: 600 rpm
Flywheel
Rotary
encoder
Electric motor
Okayama University
Compression-expansion engine
Side view
Top view
Water
Bore: 78 mm
Stroke: 85 mm
Compression ratio: 9.0
Engine speed: 600 rpm
Unburned gas
Burned gas
Out
In
Valve closing
180 210
(BDC)
Timing chart
240 270
Ignition
300 330
Crank angle, deg.
360
(TDC)
Okayama University
Compression-expansion engine
Experimental condition
n-C4H10 (94)
H2
1.0
1.0
40, 50, 60kPa
40kPa
335～355deg. 335～360deg.
Fuel (Octane number)
Equivalence ratio, φ
Initial pressure, P0
Spark ignition timing, θIT
Use of Ar&O2 mixture instead of air
4
3
H.P.F
2.5kHz
2
1
0
360
380
Crank angle, deg.
400
In te n s ity , M P a
P re s s u re , M P a
Knock intensity: KInt
0.4
0.2
KInt
0
-0.2
-0.4
0
0
0.005
0.01
0.015
10
5
15
Time
from
ignition,
s
Time from ignition, ms
Okayama University
Experimental condition
Mirror
Measurement
point
Cylinder
Valve
High-speed video camera
Shimadzu Hyper vision, HPV-1
Nac Image Technology, MEMRECAM GX1
Cassegrain
optics
Pressure
Transducer
PC
Electric motor
Flywheel
Experimental methods
Spark
electrode
n-Butane(Φ=1.0)
Rec.Speed:32kf.p.s Rec.Expose:1/8
P ressu re, M P a
P0=50kPaΘIT=350deg.
P0=60kPaΘIT=340deg.
KInt=0.180MPa
Standard cycle
4.0
P0=60kPaΘIT=345deg.
KInt=0.434MPa
3.0
2.0
1.0
0.0
320
340
360
380
400 320
340
360
380
400 320
340
360
380
Crank angle, deg.
Okayama University
Knock image (n-Butane)
400
a
b
c
d
e
f
g
Pressure, MPa
Normal cycle
4
4
3
3
2
2
1
0
350
Auto-ignited
kernel
A
360
P0=50kPa
qIT=350deg. 1
0
370
380 350
Flame front
B
P0=60kPa
qIT=345deg.
360
Crank angle, deg.
C
D
370
380
Knocking cycle
E
F
G
4.0
KInt=0.491MPa
3.0
Rec.speed:63kfps
2.0
360.0deg.～366.4deg.
B Flame front
C
A
0
350
P re s s u re , M P a
Auto-ignited
kernel
1.0
4.0
355
360
365
370
ABCDEFGHI
3.5
Φ=1.0
P0=60kPa,
ΘIT=345deg.
3.0
2.5
361
362
363
364
Crank angle, deg.
D
E
F
G
H
I
Okayama University
Knock image and pressure history (n-Butane)
4.0
KInt=0.491MPa
3.0
Rec.speed:64kfps
2.0
360.0deg.～366.4deg.
1.0
B
C
A
P re s s u re , M P a
0
350
4.0
355
360
365
370
ABCDEFGHI
3.5
Φ=1.0
P0=60kPa,
ΘIT=345deg.
3.0
2.5
361
362
363
364
Crank angle, deg.
D
E
F
G
H
I
Okayama University
Knock image and pressure history (n-Butane)
f = 1.0 , P0=60kPa , T0=323K , Rec.speed : 20kfps.
C4H10 , ΘIT=345deg.
Kint=0.07MPa
C4H10 , ΘIT=360deg.
Non-knock condition
CH4 , ΘIT=340deg.
Non-knock condition
Pressure , MPa
4
3
2
1
0
320 340 360 380 400 420 320 340 360 380 400 420
Crank angle , deg.
Crank angle , deg.
320 340 360 380 400 420
Crank angle , deg.
Okayama University
Knock image and pressure history (n-Butane)
Normal cycle
Pressure, MPa
Rec. speed=60,000fps
3
2
H2-Air
φ=1.0
P0=60kPa
T0=323K
θi=360deg.
Kint=0.03MPa
Knocking cycle
Rec. speed=60,000fps
3
2
1
1
0
360
0
360
365
370
375
Crank angle, deg.
380
H2-O2-Ar
φ=1.0
P0=40kPa
T0=323K
θi=360deg.
Kint=1.53MPa
365
370
375
Crank angle, deg.
380
Okayama University
Compared normal cycle with knocking cycle
Pressure wave
H2-O2-Ar
φ=1.0
θi=340deg.
Rec.
speed=250,000fps
Exposure time=2ms
Kint=0.99MPa
Pressure, MPa
Knocking cycle
Pressure, MPa
3 2
Auto-ignition
2
1.5
A1
A2
B1
136ms
1
1
345
0
330
Frequency=7.35kHz
B2
345.5
340
346
CA, deg.
350
346.5
360
370
CA, deg.
Okayama University
Visualization of pressure wave and estimation of the frequency