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8/10/2019 OBD & NOx Anti-tampering System Architecture
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Be
ingenious
OBD & NOxanti-tampering system architecture
experiences & lessons learned
BRACE AutomotiveMarcel Romijn
Competences coordinator
OBD & Emission specialist
CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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Be
ingenious Introductiono Often overlooked are consequences of OBD and NOxanti-tampering legislations to system
architectures.
o Also how unclear boundaries of the OBD system can generate problems.
o Even more valid for heavy-duty on- and off-highway.
o This presentation aims to discuss these potential problems and the lessons to learned.
Agenda:
o Vehicle Diagnostics overview
o Legislation requirements impacting system architectureo Diagnostic Master & Slave
o Use of off-the-shelf smart sensors & actuators from suppliers
o Architecture consequences on legislation compliance, required service information &
emissions warranty
o Concluding
2CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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Be
ingenious Vehicle Diagnostics overviewEngine
OBD (emissions)
NOxinducements
(EGAS) Functional Safety
Safety (e.g. fire risk) Service
Transmission
OBD (emissions)
Functional Safety
Service
Brakes & Vehicle dynamics
Functional Safety
Service
Driver assistence systems
Functional Safety
Service
Comfort systems
Functional Safety
Service
Supplier to Vehicle OEM OEM is the responsible coordinator
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Be
ingenious Vehicle Diagnostics overviewEngine (by Engine OEM) OBD (emissions)
NOxinducements
(EGAS) Functional Safety
Safety (e.g. fire risk)
Service
Transmission (by supplier) Functional Safety
Service
Brakes & Vehicle dynamics (by supplier) Functional Safety
Service
Driver assistence systems Functional Safety
Service
Comfort systems Functional Safety
Service
Engine OEM & suppliers to Vehicle OEM to Bodybuilder Responsible coordinator?
Work application (by Bodybuilder) Functional Safety
Service
4CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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Be
ingenious Vehicle Diagnostics overviewEngine (by Engine OEM) OBD (emissions)?
NOxinducements
(EGAS) Functional Safety
Safety (e.g. fire risk)
Service
Transmission (by supplier) Functional Safety
Service
Brakes & Vehicle dynamics (by
supplier) Functional Safety
Service
Driver assistence systems Functional Safety
Service
Comfort systems (by supplier)
Functional Safety Service
Engine OEM & suppliers to Machine OEM Responsible coordinator?
Work application Functional Safety
Service
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ingenious
6
Legislation requirements impacting system architecture
o Engine
o Driver interface (warnings)
o Transmission
o Aftertreatment
Concept of OBD & Emissions domain
o Concept to clarify the legal requirements
o Legislation requirements can define thedomain
o Engine & Aftertreatment are always in
o An engine-dyno certification meanstransmission is not part of the domain
o Hybrids are a difficult exemption
o Special domains, responsibilites &certification procedures for Hybrids
o OBD & NOxwarning system may be part ofdomain
CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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ingenious
Legislation requirements impacting system architecture
Concept of OBD & Emissions domain
o US legislation is very strict, while EU & others only so-so
o Any input to an OBD diagnostic = OBD & Emissions domain
E.g. switch off Misfire diagnostic with low fuel tank level or when Traction Control (via CAN)requests torque limitation
o Any input to Emissions controls = OBD & Emissions domain
E.g. adapt EGR rate on Ambient temperature or the vehicle air pressure system as actuating
medium for Urea injector
o Any system/component possibly impacting emissions or OBD =
OBD & Emissions domain
E.g. Arctic Start Ether Support System, Wait-to-Start or Glow-plug light Systems,
Start-Stop, Cooling Systems, Driver modes (ECO, Sport), Cruise Controls
Domain
Signals to domain
Commands from domain
X
X
Arctic Ether start
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Legislation requirements impacting system architecture
When inside the OBD & Emissions domain
o Full-blown OBD monitoring on sensor signals
E.g. Electrical, Ranges, Plausibility, CAN-bus
o Full-blown OBD monitoring on actuators & commands
E.g. Electrical, Commands Response (whole actuator system), CAN-bus
o Possibility of being a DECECU (Diagnostic or Emission Critical ECU)
E.g. ECU OBD monitoring (Processor, Memory, Supply Voltage), Support CAL-ID (SW and Cal.
part number) & CVN (SW and Cal. verification calculation)
Domain
Signals to domain
Commands from domain
X
X
8CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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ingenious
Many control units possibly in OBD & Emissions domain
o Should they all communicate individually to OBD Scantool?
o Should they all keep their own storage of faultcodes and related information?
Diagnostic Masters & Slaves
Ambient
air T
Engine ECUAftertreatment
ECU
Cooling fan
EGR valve
VGT
actuator
Glow plug
control
Swirl valves
Urea pump
ABS Vehicle
speed
NOx sensor
NH3 sensor
PM sensor
Driver
interface
OBD
Scantool
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ingeniousDiagnostic Masters & Slaves
Look at the source of the information
No point in sending engine speed data to a NOxsensor, rules out the
possibility of diagnostics that require engine speed based enabling to be
founded in NOxsensor.
System
Plausibility
Range
Electrical
Systeminterpretation of
sensor value
Environment inwhich the sensor
measures
Electrical circuitof the component
Short/Open circuits; usually all the Volt, Amps, Ohms things
Placement of diagnostics based on diagnostic levels and information need
Does the whole system act as it should?
Does the value make any sense?
Exceeding normal measurement range; in unit of the sensor
Every diagnostic needs information
The monitored value and enabling conditions
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Use of off-the-shelf smart
sensors/actuators from suppliers
Typical Heavy-Duty Diesels = large amount off-the-shelf parts
o Economy-of-scales cost reduction reasons
o Makes diagnostic responsibility a multi-company task
o Many (sub)suppliers have little knowledge about i.e. OBD & NOxanti-tampering
o Purchasing contracts often not technically deep enough
o Lack of important details or even requesting only OBD compliance as a generic term
o Makes all the ingredients for a disastrous development project!
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Use of off-the-shelf smart
sensors/actuators from suppliers
False PASS scenario with off-the-shelf part based on real-life experience
o Smart valve (i.e. EGR) based on stepper-motor & butterfly valve; internally diagnosed for stuck
butterfly valve by means of internal control error
o CAN communication consisted of 1 bit per internal fault.
If bit = FALSE; Then PASS status to fault code storage & scan tool info
If bit = TRUE; Then FAIL status set to fault code storage & scan tool info
o Now ask yourselves; what is a scenario of a stuck valve?
Say the valve can not move to more than 50% opening due to blockage
Valve works fine below 50% opening
13CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
14CTI 3 d I t ti l C f H D t Di l Di ti 9th O t b 2014
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ingenious
Use of off-the-shelf smart
sensors/actuators from suppliers
CAN bit =
FALSEPASS
Setpoint50%; so FAIL is set
o Fault is now self-healed at every engine start or when setpoint is
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ingenious
Use of off-the-shelf smart
sensors/actuators from suppliers
False PASS issues with off-the-shelf parts; a real life experience contd:
o Two solutions investigated:
1) Blame the new-to-OBD (sub)supplier: Modify the internal diagnostic by adding enabling conditions
2) Let the OBD engineers fix it: Dont forward directly the (sub)suppliers internal status to fault handling
o With 1, the supplier needed to wait for diagnosing unless the setpoint was at higher level
What to do with the 1 bit fault reporting in CAN? When not TRUE is that a PASS or just a Dont know yet?
o With 2, make the OBD master handle the waiting for diagnosing until a relevant setpoint
In the meantime ignore whatever the smart valve was sending in fault reporting
o This experience has come again and again in many situations and systems
Even outside OBD such as Safety related diagnostics
15CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
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ingenious
Use of off-the-shelf smart
sensors/actuators from suppliers
DECECU (Diagnostic or Emission Critical ECU) in USA:
o Check up-to-date legislationboundary between component and ECU
o Typical example: more then 2 Components (e.g. Sensors)DECECU
o Example: Smart valve
Components: Stepper motor (actuator), position sensor, and PCB electrical circuits temperature sensor (overheat protection)
o Usually only first two used; thus not a DECECU
o However, PCB temperature sensor can also be used by OBD master in assisting e.g. Engine Coolant
Temperature plausibility check
o Now all three are used and therefore DECECU
o Special Note:
The same component can be a DECECU in one application and not be a DECECU in another application
Makes for interesting discussions between OEMs, suppliers and sub-suppliers!
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Architecture consequences on legislation compliance,
required service information, and emissions warranty
What are the consequences if we end up with a compliancy disaster?
o False PASS or no-detections give rise to problems with legislator in USA
Many of these are found in required tests on series-production vehicles either performed by OEM or performed by legislator
o False FAIL or non-existent failures give rise to problems with customers
Legislator is unhappy too because it generates a bad image regarding required OBD & NOxanti-tampering systems
o Possible consequences
1. (Forced) recall & warranty costs
2. Exposure in news; (i.e. http://www.epa.gov/otaq/cert/eng-recall/recall.htmor http://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defects)
3. Possibly fines
17CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
http://www.epa.gov/otaq/cert/eng-recall/recall.htmhttp://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defectshttp://www.nhtsa.gov/Vehicle+Safety/Recalls+&+Defectshttp://www.epa.gov/otaq/cert/eng-recall/recall.htmhttp://www.epa.gov/otaq/cert/eng-recall/recall.htmhttp://www.epa.gov/otaq/cert/eng-recall/recall.htm8/10/2019 OBD & NOx Anti-tampering System Architecture
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ingenious
Architecture consequences on legislation compliance,
required service information, and emissions warranty
Information exchange
o A lot of information must be disclosed about the workings of Emissions system and OBD
During type-approval application and during the vehicle lifetime on a publicly available Service Information website
o Includes also info from the off-the-shelf components internal workings
Again; great fun in discussions between OEMs, suppliers and sub-suppliers
o Some examples of the public available information:
Detroit Diesel: https://ddcsn-ddc.freightliner.com/cps/rde/xchg/ddcsn/hs/5712.htm
Ford (incl. Heavy-duty): https://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=diag_theory_retail&gutsid=diagsheet&menuIndex1=10
General Motors: https://service.gm.com/gmspo/mode6/index.html
19CTI 3rd International Conference Heavy-Duty Diesel Diagnostics9th October 2014
20CTI 3rd International Conference Heavy-Duty Diesel Diagnostics 9th October 2014
https://ddcsn-ddc.freightliner.com/cps/rde/xchg/ddcsn/hs/5712.htmhttps://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=diag_theory_retail&gutsid=diagsheet&menuIndex1=10https://service.gm.com/gmspo/mode6/index.htmlhttps://service.gm.com/gmspo/mode6/index.htmlhttps://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=diag_theory_retail&gutsid=diagsheet&menuIndex1=10https://ddcsn-ddc.freightliner.com/cps/rde/xchg/ddcsn/hs/5712.htmhttps://ddcsn-ddc.freightliner.com/cps/rde/xchg/ddcsn/hs/5712.htmhttps://ddcsn-ddc.freightliner.com/cps/rde/xchg/ddcsn/hs/5712.htm8/10/2019 OBD & NOx Anti-tampering System Architecture
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Be
ingenious Concluding
OBD, NOxanti-tampering & other diagnostics are always challenging
o Usage in Heavy-duty domain adds more challenges
o Understanding responsibilities throughout the vehicle/machine is key
o Create boundaries with clear and limited I/O interfaces
o Just sourcing components already requires focus on many items unknown to many outsiders
o Things that seem not important or were never important before can have the biggest financial impact
o Knowledgeable (sub)suppliers can be of great help
o (Sub)suppliers that are unaware can however create a nightmare scenario
o (Sub)suppliers need to be prepared to see very different demands of their products depending on
application
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