Efficiency and Emission Improvements for Future
Off-road Engines
Rich WinsorBryan GeisickDanan Dou
June 3, 2015
Agenda
• Introduction to Off-road Engines
• Customer Needs
• Emission Control
• Fuel efficiency, power growth, and heat rejection
2
Extreme Operating Conditions for Off-Road
3
Wet Cold & Hot Dusty Off-Level
High Altitude - Mining at 14,000 ftRemote worksitesSeasonal use
John Deere Diesel Engine Applications
4
MachineApplications
Agriculture Construction& Forestry
External OEMs
4.5L 6.8L
9L 13.5L
5
7310R Record Previous RecordholdersTest Condition kg/kWh kg/kWh
75% Max pull, full throttle 0.255 John Deere 720 0.258 *
50% Max pull, full throttle 0.282 Deere 7810 IVT 0.284
* 58 year old Record
Drawbar Results @ Nebraska Tractor Test Lab
6
DLG Official Test Results - Stage IV
PowerMix TransportDiesel DEF Total Diesel DEF Total
Fendt 828 Vario 248 14 262 486 19 505JD 7310R e23 248 9 257 450 12 462
800 1000 1200 1400 1600 1800 2000 2200
Torq
ue
Engine Speed (rpm)
13.5L Tractor13L Truck
Off-Road Engines Operate Differently
7
Tractor Engine: extended time at high speed and loadOptimize for productivity and fuel efficiency
Truck
800 1000 1200 1400 1600 1800 2000 2200
Torq
ue
Engine Speed (rpm)
Row Crop Tractor
Combine
Applications Require Different Torque Curves
Tractors: High torque at low speed for vehicle launchingHigh torque rise for difficult conditions
Combines: Maximum power
8
Tractors etc. HarvestersConstruction & Forestry
Power (kW)
Wide Power Range and High Configuration Variance
9
Volume
Power (kW)
Trade-off Summary of Low vs. High Power
10
Low kW/L vs High kW/L
Power
Torque
BSFC
$ /kW
EmissionCold Start
Durability
Altitude
Transient
Multiple FT4 Configurations(Three 4045 engines shown)
Five engine platforms (3029, 4045, 6068 , 6090, 6135)Twenty performance hardware sets (turbos, injectors,
pistons, cylinder heads, exhaust manifolds, etc.)~55 base calibrations with multiple torque curves on most
11
100%
300%
500%
700%
900%
1100%
1300%
1500%
1700%
1900%
Stage I Stage II Stage IIIA Stage IIIB Stage IV
# of
Fun
ctio
ns&
DTC
Electronics and Intelligent Software Provide Flexibility in System Integration
12
48 pinIn-line fuel pump
Fuel SystemAir SystemEmission SystemDiagnosticsTelematics…
162 Pin
13
0
200
400
600
800
1000
1200
1400
1600
1800
600 800 1000 1200 1400 1600 1800 2000 2200 240015%
10%
15%
15%
15%
10%
10%
10%
Engine Speed (rpm)
Torq
ue (N
m)
NRTC
8 Mode
Non-Road Emission Test Cycles:8 Mode (>T1), NTE (>T3), Transient Cycle (>IT4)
Bubble size & value: weighing factor
Deere Final Tier 4 System ArchitectureFT4 Standard: PM=0.02g/kWh, NOx=0.4g/kWh
14
Emission System
DOC-DPF for PMEGR and SCR for NOxDEF storage and deliverySensors & control System
Value Proposition
High performanceLow fluid consumption
0
0.1
0.2
0.3
0.4
63 129 92 224 168 317 241 460
Tailp
ipe
NO
x (g
/kW
h)
Power (kW)
FT4 Fulfilled for Wide Power Range
Emission Standard
13.5L9L6.8L4.5L
Min Power, Max Power
15
Low Power Output Produces Low Temperature (More Challenging for SCR Performance)
High Power Rating
Low Power Rating
Cold NRTC Hot NRTC20min Soak
16
NRTC=Non Road Transient Test Cycle
High Power Rating
Low Power Rating
↓Poor SCR Activity ↓Poor SCR Activity
Realize CO2 Reduction from Combustion, Air System and Mechanical Design
17
Indicated Power
Brake Power
Friction* & Auxiliary
Pumping Loss
WasteEnergy
ExhaustEnergy
Water Cooling
Charge Air Cooling
ATRestriction
ATCooling
SCR Warmup
DPF Regen
Primary Secondary
-3%
-2%
-1%
0%
1%
2%
3%
1 2 3 4 5 6 7
Flui
d C
ost C
hang
e
Engine Out NOx (g/kWh)
Fluid Consumption Optimum Vs. Fuel/DEF Cost Ratio (EGR Engine Scenario)
18
Fuel/DEF Cost = 1
Fuel/DEF Cost = 2
Fuel/DEF Cost = 3
OptimumRange
~92% NOx Eff
Minimizing Total Fluid Cost
• Modern EGR engine offers superior BSFC
• Engine out NOx level: 2.5 - 5 g/kWh
• High NH3 uniformity for SCR reactions
• Model based controls and calibration optimization
• Ensure NH3 availability for emission compliance
• Limit NH3 storage to avoid NH3 thermal release
• EGR and SCR optimization: emission and performance
19
What’s Next: Power and Efficiency
Higher Fuel EfficiencyLower Specific Heat RejectionPower GrowthHigher NOx/PM RatioNext Gen ECUImproved Diagnostics (DEF Quality Sensor)
Particle Number ComplianceDown SizeLower CostIntegrated PackagingLower RestrictionInnovative CatalysisReduced Active Regeneration
Integrated System Solution
+
20
Heat Rejection is Important in Off-highway Applications
• Dirty environment without ram air results in cooling difficulty
• Debris can interfere with cooling
• Lower fan power improves vehicle fuel economy
• Higher specific output reduces specific heat rejection
21
Combustion now focuses on efficiency, power and heat rejection rather than emission characteristics.
23
Capability of Exhaust Aftertreatment Broadens Design Space
24
Combustion System Development Process
Swirl Testing
Combustion
Simulation
Test
Design
Port design
Combustion CFD
Air motion CFD
Fuel Sprays
25
Analysis-Based Design Effort:Initial CFD Correlation with Test Results
ISSUES:Boundary Conditions – pressure,
temperature, EGRSurface TemperaturesCombustion ModelGrid resolution
Rate of Injection (ROI)Soot Model
Improved CFD Results on Same Hardware Sets
Model improvements significantly improved the correlations, but it appears further effort on fuel sprays is needed.
26
Diesel Combustion System Design
• Designed for highest loads; lighter loads allow more flexibility in injection process
• Diesel fuel will burn with 99+% efficiency unless situation is unusual – misfire or excessively rich
• Diesel combustion is generally mixing controlled, not kinetically controlled, after ignition
• When the heat is released is important – start slowly and finish at high rate for efficiency without excessive cylinder pressure
• Timing and quantity of in-cylinder heat loss is important
• With DPF and SCR, PM and NOx emissions have less importance
27
EGR is not just for Emission Control
• EGR reduces temperatures of piston, cylinder head, exhaust manifold, turbocharger, exhaust throttle and aftertreatment, although system heat rejection is increased
• With an optimized air system, fuel economy with EGR is at least as good as without EGR
• EGR reduces DEF consumption by the SCR system
• EGR is no longer a limiting factor for low engine-out PM due to newer combustion systems
28
Combustion System Issues
• Compression ratio (expansion ratio)• Heat loss – wasting energy• Time loss – not burning at optimum
time• Engine speed – more time at low
speed• Smoke and PM do not indicate poorer
combustion in a general sense –heating value of smoke is negligible
• Higher NOx tends to indicate faster combustion
• High swirl systems may give fast combustion and low smoke, but heat loss can be high
• Quiescent combustion systems can give higher efficiency, although PM may be slightly higher
29
Combustion System Generalizations
Parameter Legacy Split-Spray Low TurbulencePM base lower higherNOx base higher higher
Rated BSFC base same lowerPart Load BSFC base lower same
Head Temp. base lower lowerPiston Temp. base higher lower
Heat Rejection base same lowerOil Sooting base better worseApplication FT4 No DPF High Power
30
10
15
20
25
30
35
1970 1980 1990 2000 2010 2020
Pow
er D
ensi
ty (
kW/L
)
Year
Continuous Demand for Power GrowthExample: Tractor Power Increase Over Time
31
Approach for Power Growth
• Injection system – larger pump, if necessary• Air system – staged turbocharging• Reduce torque rise, if possible• Strengthen parts as necessary to tolerate higher
cylinder pressure• Design combustion systems with lower thermal
loading on combustion chamber• Improve head, piston and liner cooling• Possible turbocompounding
32
Electric Turbocompounding
Increased powerReduced fuel consumptionFlexible installation of unitRequires vehicle to use
electrical power, esp. at high loads
33
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