1. 2010 Heavy Duty OBD Overview
Marc Allain
Detroit Diesel

2. OBD Requirements Overview Aftertreatment System Technical Challenges
Outline
OBD Requirements Overview
Aftertreatment System
Technical Challenges
Summary

3. 2010 Heavy Duty OBD Requirements
Injection System
Fuel Flow
Pressure
Timing
Misfire
Major monitors
Air system
EGR system
Injection system
Misfire
Cooling system
Crankcase ventilation
DOC
DPF
SCR
Rationality checks
Sensors
Actuators
Comprehensive component monitors
Circuit continuity checks
Crankcase Ventilation
Cooling System
Thermostat
Grid Heater
EGR System
EGR Valve
EGR Cooler
Air System
Turbocharger
Charge Cooler
SCR System
SCR Efficiency
Urea Doser
Urea Quality
DOC
DPF
DOC/DPF
Filtration Efficiency
Incomplete Regeneration
HC Doser
HC Slip
SCR

4. 2010 Heavy Duty OBD Requirements
OBD monitors must provide:
- Fault detection below OBD emissions thresholds
Monitoring frequency > legislated ratios

5. Aftertreatment OBD – Major Monitors
SCR NOx conversion efficiency
DPF filtration efficiency
- NOx sensor malfunction
DOC HC conversion efficiency
- HC doser malfunction
- DEF doser malfunction
DEF quality
Major technical challenges
NOx sensor accuracy
Multiple vehicle applications
Fault separation
Threshold part development
Good SCR
Bad SCR
SCR Efficiency
Need sufficient separation to prevent false codes
NOx (g/hp-hr)
0.2
0.6
OBD Threshold

6. Aftertreatment OBD – Major Monitors
DPF DP
SCR NOx conversion efficiency
DPF filtration efficiency
DOC HC conversion efficiency
HC doser malfunction
NOx sensor malfunction
DEF doser malfunction
DEF quality
Major technical challenges
Highly dynamic engine operation
- Threshold part development
Varying backpressure
2013 Requirements
NO/NO2 ratio monitoring
Catalyzed DPF HC conversion efficiency
Impacted by exhaust flow rate accuracy
Good DPF
Cracked DPF
Exhaust flow rate
Nominal
Air system drift

7. Technical Challenges Emission Threshold False Passes Codes
Monitoring Frequency
Threshold Parts
Technical Risk
OBD monitors must provide:
- Sufficient false code margin
- Sufficient false pass margin
Test cell work
Calibration
Threshold part development
Emissions impact
- Steady-state conditions
- Transient cycle
- Hot/cold
- DPF regeneration
Vehicle validation
With faults in place
With nominal hardware
Loaded/bobtail
Hot/cold ambient
Aftermarket accessories
Offline validation
Statistical false code margin evaluation

8. Summary
New OBD requirements being phased in starting in 2010
Every engine system is impacted
OBD development challenges
- Low emission thresholds
- OBD-specific hardware required
- False code & false pass margin needed
- Extensive vehicle validation required
- Statistical evaluation of dozens of monitors
Additional legislated requirements starting in 2013
- Lower OBD emission thresholds
- Higher performance ratios