OBD & NOx Anti-tampering System Architecture

8/10/2019 OBD & NOx Anti-tampering System Architecture

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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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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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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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ingenious Vehicle Diagnostics overviewEngine (by Engine OEM) OBD (emissions)

NOxinducements


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



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ingenious Vehicle Diagnostics overviewEngine (by Engine OEM) OBD (emissions)?

NOxinducements


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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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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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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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



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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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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


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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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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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


16CTI 3 d I t ti l C f H D t Di l Di ti 9th O t b 2014


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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!


17CTI 3rd International Conference Heavy Duty Diesel Diagnostics 9th October 2014


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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

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.htm


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19CTI 3rd International Conference Heavy Duty Diesel Diagnostics 9th October 2014


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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


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.htm


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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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OBD & NOx Anti-tampering System Architecture

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