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BMW Group Wolfgang Mattes BMW Diesel. DEER 2007 Page 1 13th DEER Conference, 13-16th August 2007 Detroit The BMW Approach to Tier2 Bin5 Wolfgang Mattes BMW Group
BMW Group Wolfgang Mattes BMW Diesel. DEER 2007 Page 1 13th DEER Conference, 13-16th August 2007 Detroit
The BMW Approach to Tier2 Bin5
Wolfgang Mattes
BMW Group
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Page 2 Contents.
• Challenges in the US market
• Tier2 Bin5 Concept Æ Internal Engine Measures Æ Aftertreatment: SCR System Æ OBD
• Summary
BMW Group BMW Diesel. Wolfgang MattesDEER 2007 Challenges in the US-Market.Page 3
• Stringent emission legislation Æ limits and test-procedures
• High requirements to OBD Æ new engine control functions
• Intensified climatic edge conditions Æ altitude up to 4000 m
• Customer expectations Æ noise, vibrations, harshness
• Various fuel quality with large dispersions Æ combustion noise, driveability
Æ New technologies are necessary Æ Robust, sustainable solutions are required
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 NOx Challenge BIN 5. Page 4
NOx 0,98 g/mi
Tier 1 LDT3 0,60
Tier 2 Bin 10 (till MY´08) -94%0,14
0,10 0,05 0,10 0,32 0,075 0,23 NMHCPM 0,08
g/mi Tier 2 Bin 8 (MY´09) g/mi Tier 2 Bin 5 (MY´09)
3,4X5 3.0d with EU4technology incl. DPF
6,4 CO g/mi
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Test cycles.Page 5
pm_e
[ba
r]
22 20 18 16 14 12 10 8 6 4 2 0
1000 1200
1400
1600
US 06 FTP 75
EDC 600 800
SC 03 N NOx [g/h] 400
100 200
1000 1500 2000 2500 3000 3500 4000 4500
Engine speed [min-1]
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Targets for BMW US Diesel. Page 6
• BMW typical fun to drive
• Fulfill 50 state legislations (Æ Tier2 Bin5)
• BMW Diesel Strengths:
- Low fuel-consumption
Æ 20-30% below comparable petrol cars Æ cost saving, sometimes supported by low fuel costs Æ high cruising range
- Fun to drive, outstanding torque characteristics
Æ relaxed cruising Æ torque on demand Æ good NVH due to low engine speed
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 TIER2 BIN5 Concept.Page 7
DieselParticulate Filter
SCR-System(Urea)
ModifiedCombustion with 2stage Turbocharging
OBDSensors and
Functions
AdvancedEGR-System
Piezo Common-RailFuel Injection
System
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Page 8 Combustion.
Æ Central injector position
Æ 4 valves per cylinder
Æ Symetrical combustion chamber
Æ Variable air control
Inline 6. Displacement 2992 cm³ Single Cylinder Displ. 499 cm³ Bore / Stroke 84/90 mm Max. Combustion Pressure 180 bar
Page 9
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Piezo Common-Rail System.
• Very quick needle opening and closing for effective combustion
• Up to 5 shots per combustion stroke
• Very low tolerances of injection quantities
• Long term learn-algorithm for injection control
• High pressure pump with feed volume control
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 2-Stage Turbocharger (Variable Twin Turbo). Page 10
Engine
Small Turbo
Big Turbo
Intercooler
Compressor-Bypass
Air Exhaust
Turbine-Bypass
Waste-Gate
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Page 11 Variable Twin Turbo – even more powerfull.
630
560
490
420
350
280
210
140
70
0
Torq
ue [N
m]
Pow
er [k
W]
0 1000 2000 3000 4000 5000 Engine speed [min-1]
225
200
175
150
125
100
75
50
25
0
Variable Twin Turbo 3,0 l : 560 Nm at 2000 min-1
200 kW at 4400 min-1
Base engine 3,0 l (MJ 05) : 500 Nm at 2000 min-1
160 kW at 4000 min-1
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Variable Twin Turbo – compact design. Page 12
small turbo
big turbo
compressor-bypassturbine-bypass
waste-gate
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 EGR-System.Page 13
EGR
High Pressure - EGR
Low Pressure
PUM_Seid_MnoxAbgas [g/h]
0
2
4
6
8
10
12
14
BE
[g/k
W.h
]T2
2 [
C]
P21
[mba
r]
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Low Pressure EGR-System.
1500 min-1 / 6barPage 14
150
Effect of Low Pressure EGR: • Reduced charge temperature
• Higher boost pressure (efficiency turbocharger)
• Better fuel economy
• 30% NOx-advantage
0 10 20 30 40 50 60 70 80 90 100
E_R
USS
_A [g
/h]
16
210
220
230
240
250
260
°
0
75
200
400
600
T V57445809.217 T V57445809.219
HD-AGR ND-AGR
NOx [g/h]
[g/k
Wh]
[m
bar]
[°C
]
charge temperature
boost pressure
fuel consumption
PM P
M [g
/h]
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Closed Coupled Particulate Filter. Page 15
No power loss (low flow resistance) Particles are filtered No significant increase in FC and burnt off in the Reduced HC/CO-emissionsceramic filter with its Reduced system effort catalytic coating.
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 SCR System Overview.Page 16
Core Components:
• Urea Tank • Dosing Module Urea Tank • Mixer • SCR-Catalyst • NOx-Sensor • Control Unit / ECU
Dosing NOx-SensorModule
Oxi-Catalyst DPF Mixer SCR-Catalyst
Source: Bosch
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Page 17 SCR – Chemical Reactions.
Reduction
NO + NO2 + 2 NH3 Æ 2 N2 + 3 H2O
4 NO + O2 + 4 NH3 Æ 4 N2 + 6 H2O
6 NO2 + 8 NH3 Æ 7 N2 + 12 H2O
(NH2)2CO Æ NH3 + HNCO Thermolysis
HNCO + H2O Æ NH3 + CO2 Hydrolysis
Oxidation
NO + ½ O2 Æ NO2
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 CFD-Simulation of NH3-Distribution.Page 18
TargetsTargets • Improve Ammonia distribution → maximum conversion
• Reduce Ammonia slip, because of overloaded catalyst cells
• Best possible usage of mixing element
• Analysis of pressure drop and optimisation
Modelling ApproachModelling Approach
• Transient CFD Simulation with StarCD
• Two component droplets (water, urea)
• Spray break-up and wall interaction
• Turbulenz modelling: k-ε RNG
• Modelling of wall film
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 Droplet Distribution.Page 19
Base Mixer Optimized Mixer
lowlowhighhigh
Droplet DiameDroplet Diam tereter
lowlow
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 Droplet Distribution.Page 20
highhigh
improved droplet
break-up
Base Mixer Optimized Mixer
huge amount of droplets pass
the mixer untouched
Droplet DiameDroplet Diam tereter
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 NH3-Vapour Distribution.Page 21
s
Optimized Mixer
lowlowhighhigh
Base Mixer
NHNH33 VapourVapour
Ein Teil der Tröpfchen wird gegen die Wand
geschleudert und verdampft
Verdampfungzentraler am Mischer
lowlow
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 NH3-Vapour Distribution.Page 22
highhigh
Optimized Mixer
better evaporation on hot Mixer
less urea evaporates on cooler exhaust
pipe wall
Base Mixer
NHNH33 VapourVapour
BMW Diesel.BMW Group Wolfgang Mattes DEER 2007 NH3-Vapour Distribution.Page 23
optimized NH3 - distribution
Optimized Mixer
inhomogeneous NH3 - distribution
Base Mixer
lowlowhighhigh
NHNH33 VapourVapour
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 NOx-Conversion @ FTP 75. Page 24
test result: 43 mg/mi NOx
high efficiency of SCR-catalyst
exhaust temperature
Ammonia slip
0 1
BMW Group BMW Diesel. Wolfgang MattesDEER 2007 OBD Monitoring Concept of SCR-System.Page 25
SCR-Catalyst Monitoring
Æ NOx converting efficiency of the SCR-catalyst is calculated using downstream and upstream NOx-concentration
Eta [-]
1
0
well- functioning catalyst efficiency threshold damaged catalyst
time
− ∫ NOx downstreamη = 1 ∫ NOx upstream
NOx-sensor tolerances are very important !
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 OBD Monitoring Concept of SCR-System. Page 26
Monitoring of Dosing / Long Term Adaptation of the System Æ Deviation from optimum converting efficiency is detected by NOx-sensor
and adaptation is carried out
• Ammonia cross sensitivity of the sensor is used
• Progression of signal curve is elementary to keep the optimum
NOx
NH3
UREA Dosing Quantity
NOx Sensor Signal NOx
NH3
Operation Point
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Summary.Page 27
NO
x [g
/mi]
Particulates [g/mi] 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Tier 1 (MDV 2) till MY´2003
EPA Bin 10 till MY´2008
EPA Bin 8
EPA Bin 5 = ULEV II
Example: X5 3.0d
- Advanced Combustion - Improved EGR - DPF + SCR
NOx -94%
DPF US applicationbased on EU 4-technology
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Summary.Page 28
• BMW at leading edge of Diesel technology.
• A whole package of technologies is necessary to fulfill thechallenging Tier2 Bin5 limits
• Engine internal measures (combustion, boost-concept, EGR)
• Aftertreatment (DPF + Urea-SCR)
• Clean Diesel technology can contribute a lot tosave the future mobility.
• Mid- and long-term potentials for further reducedemissions, fuel consumption and increased powerare under development.
BMW Group BMW Diesel. Wolfgang Mattes DEER 2007 Leading Edge Engine Technology. Page 29
Thank You for Your Attention!
