1. BMW CleanEnergy. NHA 2007, San Antonio, March 21 2007.
Combustion Analysis of a Hydrogen DI-Engine using non-invasive optical Methods
Dr. Hermann Rottengruber, Dr. Martin Schenk, Dr. Edgar Berger

2. BMW CleanEnergy. Targets H2-Powertrain Development.
Efficient dynamics:
fuel efficiency
power output
weight/volume
Efficient dynamics plays a central role in the BMW
powertrain development. Efficient dynamics means high
power output and at the same time low weight and
good efficiencies. In addition the hydrogen engine must
have emissions near zero and must be producable in a
cost efficient way.
For us, at least from a todays point of view, with an
internal combustion engine as central component in an
H2 powertrain systems efficient dynamics can be
realized best.
near Zero Emissions
cost efficient production

3. BMW CleanEnergy. Operating Strategy.
NOx-Emissions with Hydrogen (l-range)
l<1 -
exhaust
aftertreatment
NOx negligible
Quantitative
Load control
Torque
NOx [ppm]
l>>1
lean operation
NOx negligible
Qualitative
Load control
Engine Speed
So kalt, dass sogar die Luft um Leitungen friert (-160 Grad-Celsius)
So leicht, dass er ca. 14 mal leichter ist als Luft
Er verdünnt sich sehr schnell in der Luft- man kann ihn nicht schmecken, riechen oder sehen, selbst nicht wenn er brennt
Er ist nicht gesundheitsgefährdend (kann also bedenkenlos „eingenommen“ werden)
100
1.0 l l
7.0
„TWC“
„Lean Operation“
Masked out area
Lambda-area used for engine operation

4. BMW CleanEnergy. Power Output Potentials.
Gasoline PFI
Charged
H2-PFI
704 ml
air H2
mix. /mix.0 x 84 %
296 ml
H2-PFI
H2-DI
Fuel vapor
air
air H2
air H2
Fuel Volume
Air Volume
Calorific value of mixture
17 ml
296 ml
420 ml
So kalt, dass sogar die Luft um Leitungen friert (-160 Grad-Celsius)
So leicht, dass er ca. 14 mal leichter ist als Luft
Er verdünnt sich sehr schnell in der Luft- man kann ihn nicht schmecken, riechen oder sehen, selbst nicht wenn er brennt
Er ist nicht gesundheitsgefährdend (kann also bedenkenlos „eingenommen“ werden)
983 ml
704 ml
1000 ml
100 %
84 %
120 %
hVol = 1, λ = 1, VH = 1000 ml

5. BMW CleanEnergy. Engine Layout H2-DI Engine.
, storage).
central injector position
lateral injector position 2 2

6. BMW CleanEnergy. Comparison Optical Engine vs. CFD Simulation.
20° CA bTDC
60° CA bTDC
50° CA bTDC
40° CA bTDC
30° CA bTDC
optical accessible engine
stoichiometric – full load operation:
- engine speed rpm
- EOI 30° CA bTDC
- injection pressure 150 bar 2 2

7. BMW CleanEnergy. Simulation of Mixture Formation Side and Central Injector Positions.
lateral position
110° CA bTDC
50° CA bTDC
TDC
8° CA aTDC
central position
stoichiometric - full load operation:
- engine speed rpm
- EOI 30° CA bTDC
- injection pressure 40 bar 2 2

8. BMW CleanEnergy. Mixture Homogenization.
mass fraction of hydrogen within the combustion chamber
ignition
standard deviation of density distribution 2 2

9. BMW CleanEnergy. Estimation of Injection-Timing and -Pressure.
injection range 2 2

10. BMW CleanEnergy. Effect of End of Injection Timing (EOI).
ignition
cylinder pressure [bar]
volume [litres] 2 2

11. BMW CleanEnergy. Transducer Layouts for AVL VISIOLution®.
combination of
VISIOKnock® & VISIOFlame®
VISIOKnock®
knock probability [%] 30
VISIOFlame® 2 2

12. BMW CleanEnergy. Flame Propagation as a Function EOI as Calculated with VISIOFlame®.
end of
injection
0° CA
10° CA
20° CA
30° CA
40° CA
50° CA
60° CA
70° CA
80° CA
90° CA
exhaust
intake 2 2

13. BMW CleanEnergy. Engine Efficiency at Full Load.
n = 2000 min-1, pmi 12,7 bar (full load) 70 60 50 40 30 20 10
hi=
35,6 %
hi=
36,2 %
hi=
37,2 %
hi=
35,7 %
efficiency [%]
EOI 90
EOI 60
EOI 30
EOI TDC
injection losses
unburned fuel
non-ideal heat release
wall heat
charge exchange
indicated efficiency

14. BMW CleanEnergy. Injection & Gas Exchange Strategy.
intake pressure
exhaust pressure
intake pressure [bar]
exhaust pressure [bar]
injection range 130 – 0°CA bTDC (valves closed)
cylinder pressure [bar]
pos. scavenging gradient & opt. charge in using VANOS
crank angle [°CA] 2 2

15. BMW CleanEnergy. Potentials of Specific Power Output / Torque.
H2PFI
H2PFI,
charged H2
air
H2DI
Charged H2PFI and H2DI
Potential charged H2DI
Potential
charged Diesel engine
Charged gasoline engine
Charged Diesel engine
Specific Torque [Nm/dm3]
Naturally aspirated
Gasoline engine
Naturally aspirated
Diesel engine
Specific Power Output [kW/dm3]

16. BMW CleanEnergy. Conclusions.
Efficient dynamics can best be realized with an ICE:
high specific power output with l=1 operation. - high efficiencies at partial load & full load operation. - virtually no NOx- & CO2-Emissions.
Development methods for combustion processes for hydrogen ICE´s were successfully introduced.
Calibration Strategies for H2-DI-Engines were optimized
by means of power density and fuel economy.
Huge efficiency potentials using direct injection and turbo- or supercharging were identified.
Can be achieved by using production ready technology. 2 2

17. Thank you for your attention.