heavy duty on-board diagnostics - california
TRANSCRIPT
Heavy Duty On-BoardDiagnostics
California Air Resources BoardMobile Source Control Division
July 21, 2005Sacramento, California
Todayâs Presentation
⢠Background⢠Proposed OBD Monitoring
Requirements⢠Costs and Emission Impacts⢠Summary
What is On-BoardDiagnostics?
⢠A system in the engineâs on-boardcomputer that monitors the performanceof emission-related components formalfunctions
⢠Uses information from sensors⢠Mostly software that runs diagnostics in
the background
Malfunction Indicator Light(MIL)
⢠Should a malfunctionbe detected, a warninglight will appear on thevehicle's instrumentpanel to alert the driver
Standardized Information
⢠When a malfunction isdetected, information aboutthe malfunctioningcomponent is stored
⢠Technicians can downloadthe information with a âscantoolâ
⢠Information is communicatedin a standardized format soone tool works with allvehicles
How Does OBD Work?
⢠Uses information from sensors to judge theperformance of the emission controls
⢠These sensors do not directly measureemissions
Example of how OBDworks
⢠Fuel system pressure control⢠Fuel pressure sensor measures how well
pressure is controlled⢠Manufacturer correlates pressure control error
to corresponding emission increase⢠OBD system is calibrated to turn on MIL when
pressure is outside limits
Benefits of OBD
⢠Encourages design of durable emissioncontrol systems
⢠Aids diagnosis and repair of complexelectronic engine controls
⢠Helps keep emissions low by identifyingemission controls in need of repair
⢠Works for life of the vehicle
What vehicles have OBDtoday?
⢠All passenger cars, SUVs, and smalltrucks
⢠Started in 1996 for gasoline and 1997 fordiesel
⢠Over 120 million OBD II-equippedvehicles operating in the United Statestoday
Why OBD for Heavy-DutyVehicles?
⢠Substantial source of emissions⢠Engine is computer-controlled⢠Emission controls complex, numerous⢠Engines last a million miles
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Heavy-Duty DieselEmissions are Substantial
Off-Road Diesel
17%
On-Road Diesel22%
Other Mobile
Sources38%
Stationary/Area
Sources23%
NOx Diesel PM
Off-Road74%
On-Road19%
Stationary/Area
Sources6%
Source: EMFAC state-wide projection for 2010
0
1
2
3
4
5
6
g/bh
p-hr
1998 2004 2007 2010
Engine Model Year
NMHC+NOx
PMx10
Emission Standards BecomingMore Stringent
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Heavy-duty diesel enginesremain in the fleet a long time
Mileage accumulation of a 2010 MY HDD Truck
Miles Driven
0
200000
400000
600000
800000
1000000
1200000
1400000
0 5 10 15 20 25
Vehicle Age (Years)
Heavy-duty diesel enginesremain in the fleet a long time
Life of the 2010 MY HDD Truck Fleet
Miles Driven
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 5 10 15 20 25
Vehicle Age (Years)
Percent ofVehicles stillon road
Why wasnât OBD required forHeavy-Duty before now?
⢠Heavy-duty engines lag in usingelectronic engine controls andaftertreatment
⢠More stringent emission standardsstarting in 2007-2010 are changingthat
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Potential Technologies forHD Diesel Engines in 2010
Status of OBD for Heavy-Duty Engines
⢠First step taken by the Board in 2004⢠Requires Engine Manufacturer Diagnostic
(EMD) system starting in 2007⢠Basic system not tied to emissions
⢠Staff directed to come back in 2005 witha comprehensive OBD proposal
⢠Todayâs proposal is for comprehensiveOBD
Todayâs Presentation
⢠Background⢠Proposed OBD Monitoring
Requirements⢠Costs and Emission Impacts⢠Summary
Proposed Regulation:Who is Affected & When?
⢠On-road heavy-duty enginesâDelivery, trash trucks, buses, line haul, etcâDiesel and gasoline
⢠Starts in 2010âFully phased-in 2016
Proposed Requirements
⢠Threshold monitoringâ Warning light on when emissions increase X%â 8-10 per engine
⢠Non-threshold monitoringâ Functional, rational, electricalâ 75-100 checks per engine
⢠OBD testing and validationâ Pre- and post-production; by engine
manufacturer
Threshold Monitoring
⢠Most important systems (8-10), e.g.â PM filter - NOx catalystâ EGR - Fuel System
⢠Thresholds (âlight onâ) set at multiplesof emission standard, e.g.
â PM filter 5X initially 3X laterâ NOx catalyst 2.5X â 2X ââ Others (typical) 2.5X â 2X â
Phase-in
⢠Gradual, 6 year phase-inâ Addresses workload; test facility limits
⢠Full system requirementsâ 2010: 1 rating of 1 engine familyâ 2013: All ratings of 2010 family, 1-2 more
representative ratingsâ 2016 : All engines/ratings
Initial 2010 Phase-in of OBD
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Partial 2013 Phase-in of OBD
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Standardization
⢠Simplifiesdiagnosis
⢠Lower costinstrumentation(scan tools)
⢠Begins in 2013âEases implementationwith truck builders
Reduced Compliance Liability(In-use)
⢠Extrapolated systems (no testing)â No penalty if threshold exceeded
⢠Fully compliant engines (tested)â No violation unless exceed double the
thresholdâ Through 2018 model yearâ Example: NOx catalyst (2010): 5X standard
Gasoline Engine OBDRequirements
⢠Very similar to light- andmedium-duty OBD IIrequirementsâ Similar emission control
technology⢠Evaporative system monitor is
specific to gasoline engines
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OBD Testing and ValidationFour Requirements
⢠Validate threshold calibration (engineemission test)
⢠Verify communication to scan tool (ontruck)
⢠Verify that non-threshold monitors work(on truck)
⢠Verify that monitors run frequently (ontruck)
Why Is Validation TestingNeeded?
⢠OBD problems found post-productionin passenger vehiclesâ Resulted in recalls, penalties
⢠Avoid these problems with HD OBDâ Validation testing accomplishes this
⢠Volume of testing kept smallâ Spot check identifies problems
Validate threshold calibration(engine emission test)
⢠Problem: Threshold monitorscalibrated incorrectly
⢠Fix: Require manufacturer toemission test engines to verifythresholds
⢠Proposal: Test 1-3 engines per year
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Verify communication toscan tool
⢠Problem: Vehicles didnât comply withstandardization
⢠Fix: Use test equipment to confirm the truckcomplies with the specifications
⢠Proposal: Test 10 different trucks per enginefamily per year starting in 2013
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Verify that non-thresholdmonitors work
⢠Problem: Some monitors didnât work⢠Fix: Spot-check a few production vehicles
each year and verify each and everydiagnostic works correctly
⢠Proposal: Test 1-3 trucks per year startingin 2010
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Verify that monitors runfrequently
⢠Problem: Monitor rarely runs in-use
⢠Fix: Require every vehicle to track monitorfrequency and require manufacturers toreport that data
⢠Proposal: Collect and report data from 15trucks per grouping of similar vehicles
Remaining Issues:Raised by Engine Manufacturers
⢠Technical Feasibility:⢠Monitoring of all failure modes of PM filter
not possible⢠Thresholds for NOx catalyst not feasible
⢠OBD Testing and validation⢠Testing too burdensome
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PM Filter Feasibility
⢠EMA Issue: Monitoring for all failures of the PM filter isnot technically feasible
⢠Staff Response: PM filter is the most important PMemission control and monitoring method has beenidentified by staff⢠Comparison of backpressure at various exhaust flows to modeled engine
out PM levels recommended
⢠Manufacturers just now developing methodology⢠Authority in regulation to revise required failure modes and thresholds
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NOx Catalyst Feasibility
⢠EMA Issue: Thresholds for NOx catalyst monitoring arenot feasible
⢠Staff Response: NOx catalyst is one of the technologiesbeing considered to achieve the 2010 NOx standards butthe technology is not fully matured⢠Acceptability of the technology relies on a robust NOx sensor⢠Successful NOx catalyst monitoring would follow
⢠NOx sensor location could be varied to accommodate best availablesensor resolution and still achieve monitoring
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Todayâs Presentation
⢠Background⢠Proposed OBD Monitoring Requirements⢠Costs and Emission Impacts⢠Summary
Cost Effectiveness of ProposedRequirements
⢠Limited additional increase in engine cost calculated:$132 per engine (<2% of price of engine)⢠Uses existing sensors
⢠Cost-effectiveness compares favorably with otherrecently adopted regulations:⢠$0.05/lb of NOx+NMHC and $13.08/lb of PM⢠Emission benefit derived from repair of emission-
related malfunctions⢠Cost includes added engine costs plus repair costs
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⢠Several emission controls being added tomeet the stringent 2010 heavy-duty emissionstandards
⢠Proposed OBD regulation necessary to helpmaintain low emissions for entire life
⢠OBD is feasible and necessary⢠OBD is cost effective
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Summary