IITK REACH Symposium 2008
Laser Fired Low Emission
Futuristic Internal Combustion
Engines
Presented by
Dhananjay Kumar Srivastava
Research Scholar
Engine Research Laboratory
Department of Mechanical Engineering
Indian Institute of Technology Kanpur
Kanpur
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Source: D.K. Srivastava et al. 13th International symposium on power electronics, 2005
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Introduction
 As a matter of fact, excellent efficiencies of internal combustion
engines -in the first place of gas engines- of presently close to
46%.
 This requires remarkable technical improvements in general, and
especially with respect to the ignition system employed.
Increase of spark plug voltage versus
rising break mean effective pressure
BMEP
Source: D.K. Srivastava et al. Proc. SPIE Vol. 6053, 605316,Jun. 9, 2006
Engine Research Laboratory
Breakdown voltage of the spark plugs of
a large gas engine depending on the
test duration at two different BMEP
levels
Paper #
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Potential Future Ignition
System
Homogeneous Charge Compression Ignition
(HCCI)
Diesel pilot ignition
Laser ignition
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
NOx Emission Potentials
NOX [mg/Nm³]
IITK REACH Symposium 2008
350
330
300
250
250
240
190
200
150
100
70
50
0
direct
pre chamber laser ignition
spark ignition
direct
pre chamber
diesel pilot ignition
Source: D.K. Srivastava et al. Proc. SPIE Vol. 6053, 605316,Jun. 9, 2006
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Laser Ignition
An alternative solution to standard spark plug is the use of
pulsed laser, focused to create plasma, representing the laser
ignition.
Laser ignition, or laser-induced ignition, is the process of
starting combustion by the stimulus of a laser light source.
 Spark creation due to the local deposition of energy
 Ignition itself based on a positive balance between the
deposited energy and the losses
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Principle of Laser Ignition
IITK REACH Symposium 2008
convex lens
laser beam
focused laser beam
plasma
I>Ithreshold
flame kernel
E>Eignition
mixture burning
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Advantages of Laser Ignition
IITK REACH Symposium 2008
 Arbitrary positioning of the ignition plasma
 Absence of quenching effects
 Absence of erosion effects
 Precise ignition timing
 Simpler regulation of the ignition energy
 Easy possibility of multipoint ignition
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Challenges
IITK REACH Symposium 2008
 Propagation of laser pulse through fiber optics
 Develope of a compact, robust and economic laser
source
 Durability of windows
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Design of Combustion
Chamber
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Various stages of plasma growth
6 ns
12 ns
20 ns
7 ns
13 ns
22 ns
8 ns
14 ns
25 ns
9 ns
15 ns
10 ns
16 ns
35 ns
11 ns
18 ns
40 ns
Engine Research Laboratory
30 ns
45 ns
50 ns
60 ns
70 ns
80 ns
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Video of Plasma Growth
Source: D.K. Srivastava et al. SAE Paper no 2008-28.0033, New Delhi.
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Minimum Laser Pulse Energy
pinit = 5 bar
pinit = 10 bar
pinit = 20 bar
6
MPE (mJ)
IITK REACH Symposium 2008
8
4
2
0
2
4
6
8
A/Frel ( )
Laser energy, required to ignite mixture, decreases with increasing pressure of chamber
Source: M. Weinrotter et al. International J H. E. 30 (2005) 319 – 326
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Pressure History in Combustion
Chamber
λ = 2.5, laser
9
λ = 2.5, spark plug
8.5
8
λ = 3.0, laser
7
λ = 3.0, spark plug
6.5
Excess Pressure (MPa)
IITK REACH Symposium 2008
7.5
λ = 3.5, laser
6
5.5
5
4.5
4
3.5
3
λ = 3.5, spark plug
2.5
2
1.5
1
0.5
0
0
100
200
300
400
Source: D.K. Srivastava et al. SAE Paper no 2008-28.0033, New Delhi.
Engine Research Laboratory
500
600
700
800
900
1000
Time (ms)
Department of Mechanical Engineering, IIT Kanpur
40
40
35
35
30
30
pinit (bar)
init
IITK REACH Symposium
p (bar)2008
Direct comparison
laser ignition – spark plug ignition
25
20
15
25
20
15
10
1,40 1,50 1,60 1,70 1,80 1,90 2,00 2,10 2,20 2,30
A/F rel ( )
0,00
ignition reliability of laser ignition
0,25
0,50
0,75
1,00
10
1,40 1,50 1,60 1,70 1,80 1,90 2,00 2,10 2,20 2,30
A/F rel ( )
0,00
ignition reliability of spark plug ignition
0,25
0,50
0,75
1,00
For 100% ignition reliability at 30 bar
A/Frel = 2.05 (laser ignition)
A/Frel = 1.74 (spark ignition)
Source: M. Weinrotter et al. SAE 2005-01-0248
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
Laser Arrangement with Respect
to Engine
IITK REACH Symposium 2008
Pumping
Source
Laser
Optical Fiber
Laser Adaptor
Laser
ECU
ECU
Shaft Encoder
Shaft
Encoder
laser per cylinder system
Engine Research Laboratory
one laser for all cylinder system
Department of Mechanical Engineering, IIT Kanpur
Conclusions
IITK REACH Symposium 2008
Plasma propagates towards the incoming laser beam
Plasma had the maximum emission peak 30 ns after the laser was fired
and laser plasma UV-emission persisted for about 80 ns
Minimum laser pulse energy (MPE) for ignition is decreases with
increasing initial pressure
The time of pressure rise in case of laser ignition is shorter than the
spark ignition
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur
IITK REACH Symposium 2008
Thanks for Your
Attention
Engine Research Laboratory
Department of Mechanical Engineering, IIT Kanpur