Brake Emissions Testing Contributions

Research Committee Partnerships

Particle Measurement Programme (PMP)

  • Initial proposal to split the work into task-forces to develop test cycle, emission measurement method, and test report standard
  • Interlaboratory accuracy study for repeatability and reproducibility of the WLTP cycle
    • An active participant in steering team
    • Application of ISO statistical methods (ISO 5725 series) for heterogeneous materials to compute standard deviations using robust methods (repeatability, sample, lab, and reproducibility), the uncertainty of repeatability and reproducibility, regressions, and statistics for stragglers and outliers (for lab average, sample, and test repetition) heat maps
    • Development of open-source spreadsheet and final comprehensive report (pending publication)
  • Measurement of cooling behavior for six vehicles (part of the CARB project) on proving ground per WLTP to support the GRPE 81-12 cooling method
  • The lead technical writer of the GRPE 81-12
  • Several presentations regarding: sampling system guidelines using EPA, EN, and ISO standards; cooling methods; experimental comparisons
  • Informal Steering Team for second interlaboratory accuracy study with actual brake emissions measurements (2021)
  • Proposals to PMP TF4 (with experimental results) developed jointly with OEs on how to incorporate regenerative braking and state of charge for mild hybrids, full hybrid and electric vehicles

California Air Resources Board (CARB)

  • Lead laboratory for proving ground (thermal behavior only) and laboratory measurement (80+ tests) to update EMFAC model for brake emissions on six vehicles,
    different materials (OE/aftermarket, NAO/LM), loading conditions, and cycles
  • Development of core test plan for lab testing using vehicle population, brake sizes, and replacement rate (Brake Wear Index)
  • Collaborate to develop California Brake Dynamometer Cycle with real-time deceleration changes within the brake event
  • Market and industry surveys for market mix and product replacement rates

California Department of Transportation (CALTRANS)

  • Equivalent project to CARB but for commercial vehicles; seven driving cycles, ~40 tests


  • First laboratory accredited with ISO 17025 for brake emissions testing service for passenger cars, light trucks, and commercial vehicles
  • ProLINK software to replicate WLTP-Brake, WLTP-Exhaust, or other drive cycles with real-time correction for parasitic losses
  • ProLINK RegenSim 2.0 simulation to conduct emission tests for HEV or BEV platforms, with State of Charge scaling under development
  • Implementation of SAE and GTR15 metrics for speed violations and speed error
  • Open-source macro to estimate transport losses using aerosol engineering, combining several tools and methods (SAE; EPA; CDC, Max Plank Institute; Kulkarni,
    Baron, and Willeke)
  • Development of fully-integrated sampling tunnel and instrumentation cluster for PN10, PM2.5, PM10, particle size distribution (6nm to 20 µm), and time-based
    particulate mass (45 nm to 2.5 µm)
  • Self-contained weighing room (Dearborn) to weigh and report PM gravimetric filters per 40 CFR Part 1065 (CARB also follows this standard). Weighing room operation verified by EPA through an interlab study. implementation of ISO 17025-accredited weighing process for LINK Europe
  • Ability to integrate data from emissions measurement devices and sensors from multiple vendors, including signals, warnings, quality controls, and direct operation of pumps as part of the test cycle
  • Integration of electronic data output from brake emissions measurements for particle number, dilution, background emissions, and time-based particle mass with dynamometer native measurements (speed, torque, pressure, temperatures, etc.)
  • Implementation of brake emissions measurements at two LINK facilities (Dearborn and Limburg) to support corporate projects
  • First extensive DOE with high-fidelity CFD simulation including particle inception and metrics for particle size distribution


  • Agudelo, Carlos, Ravi Teja Vedula, and Tyler Odom. Estimation of Transport Efficiency for Brake Emissions Using Inertia Dynamometer Testing. No. 2018-01-1886. SAE Technical Paper, 2018.
  • Agudelo, Carlos, Ravi Teja Vedula, Jesse Capecelatro, and Qingquan Wang. Design of Experiments for Effects and Interactions during Brake Emissions Testing Using HighFidelity Computational Fluid Dynamics. No. 2019-01 2139. SAE Technical Paper, 2019.
  • Agudelo, Carlos, Ravi Teja Vedula, Sonya Collier, and Alan Stanard. Brake Particulate Matter Emissions Measurements for Six Light-Duty Vehicles Using Inertia Dynamometer Testing. No. 2020-01-1637. SAE Journal, 2020.
  • EB 2019 – Thermal and braking regimes during proving ground measurements using WLTP-Brake cycle for brake emissions measurements
  • Grigoratos, Theodoros, Carlos Agudelo, Jaroslaw Grochowicz, Sebastian Gramstat, Matt Robere, Guido Perricone, Agusti Sin et al. “Statistical Assessment and Temperature Study from the Interlaboratory Application of the WLTP–Brake Cycle.” Atmosphere 11, no. 12 (2020): 1309.
  • EB 2021 – Experimental valid

Inventory of Global Laboratory Projects for Brake Emissions Measurements

Over 10 projects for environmental agencies, vehicle manufacturers, and brake systems suppliers, including:

  • Statistical assessment and temperature study from the ` interlaboratory application of the WLTP–Brake cycle
  • Exploratory Brake Emissions Benchmarking – a Design of Experiments
  • Update emission factors for light-duty vehicles-in-operation in California
  • Update emission factors for heavy-duty vehicles-in-operation in California
  • Update emission factors for most common electric vehicle-in-operation in California
  • Elemental and organic carbon analysis of brake-generated particulates
  • Measure brake emissions for different friction materials under PMP WLTP-Brake test procedure
  • Measure brake emissions under PMP WLTP-Brake test procedure with and without regenerative braking
  • Benchmarking emissions for different friction materials of selected vehicle platforms
  • Comparison of old and new Drum design
  • OE vs prototype pads and discs. Using standard performance and wear tests
  • Survey different types of discs used on high-performance vehicles
  • EB 2021 – Experimental validation of the PMP air cooling adjustment for brake emissions measurements

LINK Brake Emissions Testing Equipment

Emissions Pro & Pro+ Dynamometers

Model 3900 NVH Brake Emissions Dynamometer

Model 4222 Brake Emissions Particle Measuring System

Download UN GTR GRPE-87-40e Cheat Sheet

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Type of TestTest HighlightsEquipment UsedExample Procedures
Chemical TestingMeasurement of copper, asbestos and other elements in brake friction materialsICP-OES / PLMJ2975
Materials TestingPhysical properties including quality control for friction, wear, compressive strain, shear strength, corrosion resistance, swell and growthChase Machine / Compressibility Machine/ Shear Machine / Corrosion Chamber / Environmental Chamber / OvenJ661, ISO 6310, ISO 6311, ISO 6312, ABNT NBR 9301, ABNT NBR 5505, ABNT NBR 5537, ASTM B117
Frequency ResponseComponent Frequency ResponseLaser Vibrometer Test StandSAE J2933, J3001, J2598, L-4375
Structural Fatigue and
Breaking strength, cyclic fatigueServo Hydraulics, Torque FlexJ2995, C419, C441, GMW18022
Caliper FingerprintingCaliper characteristics such as knockback, rollback, fluid displacement, deflection...Caliper Test Bench / Brake DynamometerL-4177, PF.90257
Brake Drag and DTVResidual drag, disc thickness variation, brake feel and vehicle fuel mileageOff Brake Drag Stand / Brake DynamometerJ2923, GMW14926, GMW14351, PF.90257, L-13080
PerformanceHydraulic, air and electric brakes, friction levels, stopping distance, corrosion, cleanability, brake torque variation, rotor cracking, regulation, stability control, coastdownBrake Dynamometer, Model 4000 DASJ2784, J2928 IS026867, GMW14985, PF.90210, PF.90244, L-405, FMVSS 121, FMVSS 122, FMVSS 105, FMVSS 135, FMVSS 126, FMVSS 136, ECE R13H, AMS
WearRotor wear, drum wear, lining wear, DTV, durability, city traffic, suburban trafficBrake Dynamometer, Model 4000 DASJ2707, USCT, L-423, PF.90244, Los Angeles, Detroit, Phoenix, Birmingham, Marquette
NVHBrake squeal during drag and decel events at different temperatures, pressure and torque levelsNVH Brake DynamometerJ2521, L420, 1430, GMW17427, PF. 90244
Brake EmissionsBrake dust particle size, count, concentration and massBrake DynamometerWLTP, CARB, Duty cycle


Type of TestTest HighlightsEquipment UsedExample Procedures
Wheel BearingWater intrusion and durability when exposed to mud and saltBearing Test StandLINK Hub and Bearing, GMW16306, GMW16310
Passenger car, sport/performance and open bed vehicle wheel bearing spallingBearing Test StandGMW16311, GMW16308, GMW16309
Brinelling resistance validates long-term reliability/durabilityBearing Test StandGMW16305
Rotary fatigue lifeRotary Fatigue MachineGMW16325
Wheel HubRotary bending fatigue life characteristicsRotary Fatigue MachineGMW14249
Hub/BearingEvaluate hub and bearing performance, durability, seals and NVH when exposed to extreme environmental effects such as temperature and mud/salt solutionBearing Test Stand/Rotary FatigueTIP-000037A, LINK Hub and Bearing, SAE J1095, LINK Impact
Hub FatigueHub fatigue using biaxial loadingBiaxial Test StandSAE J2562


Type of TestTest HighlightsEquipment UsedExample Procedures
ChemicalEvaluates filiform corrosion on painted aluminum wheels and painted aluminum trimICP-OESASTM E3061
Wheel Corrosion and CoatingsEvaluates filiform corrosion, tape adhesion, degree of rusting on painted aluminum wheels and painted aluminum trimCorrosion ChamberSAE J2635, ASTM B368, ISO 9227,
ISO 2409, ASTM D3599,
ABNT NBR 11003, ASTM D610,
ASTM D1654
Wheel FatigueLoad simulation test of aluminum alloy wheelsBiaxialBMW QV36026, SAE J2562, FORD
L-307, GMW14340
Dynamic Cornering Fatigue and Dynamic Radial Fatigue - Steel wheelsEccentric Mass and RadialABNT NBR 6750
Rotational fatigue, Radial load fatigue and biaxial load fatigue of steel and aluminum wheelsEccentric Mass, Radial and BiaxialABNT NBR 6751
Dynamic Cornering Fatigue and Dynamic Radial Fatigue and Impact resistance of temporary use and normal highway use aluminum wheelsEccentric Mass, Radial and Drop TestABNT NBR 6752
Wheel Radial FatigueRadialGMW14909
Wheel ImpactWheel Inboard Rim Flange Vertical ImpactDrop TestGMW15321
Wheel radial impactDrop TestCETP 04.04-L300
Wheel Lateral ImpactDrop TestGMW14910, SAE J175
Wheel StiffnessFrequency Response Function (FRF)Frequency ResponseGMW14876
Deformation of the wheelServo HydraulicsJ2315
Center cap heat
Center Cap deformation under elevated temperature conditionsBench TestBrake Heat Center Cap


Type of TestTest HighlightsEquipment UsedExample Procedures
Parking ForcesAllows proper sizing of power steering componentsForce and MotionLINK Parking Forces
Tire FootprintDetermines the contact patch geometryForce and MotionTire Footprint
Tire Modeling
Determine tire inertia which is then used Ftire and other models and simulationsInertia MachineLINK Tire Inertial Properties
On-center parking effort test for Ftire inputForce and MotionSWP
Determine static stiffness (X, Y, Z, Alpha) for Ftire inputStatic Stiffness MachineSAE Static Stiffness
Determine how the tire envelopes an obstacleCleat MachineJ2731
Measure the forces and moments generated at a high frequency response spindle when the tire impacts a cleatCleat MachineJ2730
Braking and Cornering PerformanceDetermine the straight line braking performance of a tireForce and MotionJ2673
Determine the free rolling cornering properties of a tireForce and MotionSAE TIME, J1987, SWP
Measure the combined cornering and braking performance of a tireForce and MotionJ2675
Tire StiffnessMeasure rolling vertical stiffness of a tire at speedRolling Vertical Stiffness
Rolling ResistanceMeasure tire rolling resistance using a drumForce and Motion, Rolling ResistanceJ1269, J2452
Tire WearAssess tire wear in the labForce and MotionLINK Wear Test
Tire NVHTest tire sizzle, cornering noise, pass-by noise, steering wheel dither, freeze crack impacts, high speed uniformity and imbalance sensitivityForce and Motion, Dynamometer, Model 4000 DASNoise, Vibration, Harshness