1. The Origins of PEMS
Leo Breton, Inventor and Developer
8th Integer Emissions Summit, Chicago
October 29, 2015
2. Inventor Had a Regulatory Compliance Mindset
Regulatory compliance is serious business
• Recalls cost OEM’s millions–don’t accuse
without certainty
• Findings could lead to lawsuits
• Testing must be technically correct and rigorous
Two parts to regs. for vehicle useful life:
1. Emit below numerical, mass-based standard
• Expensive laboratory equipment used
• Standard lab test cycle
2. Defeat devices are prohibited
• Supplemental information needed
5. Motivation for PEMS/ROVER
Dyno testing was very abstract and expensive:
• Unrealistic speeds, unchanging pattern, trained
drivers and no traffic, 68-86F temp range,
exhaust aftertreatment cooling unrealistic,
simulated electronic signals, etc.
• Emissions systems tuned to the test
Yet provided the data for everything:
• Emissions compliance, CAFÉ, emissions factors,
modeling, emissions system durability, reg.
writing what ifs?
Did dyno testing reflect reality?
6. EPA Thinking Before ROVER
Two EPA OTAQ camps of thought at the time:
1. Lab measurements are generally representative
of real world emissions
2. Even if there’s a difference, the lab results
should be proportionate, i.e. as standards get
reduced as shown by lab data, the percent
reductions would also occur in the real world
Real-world testing was not technically possible,
was not required by regulations, and was not
thought to be necessary or useful
7. Major Technical Problems Had to Be Overcome
Elimination of dilution tunnel by measuring, not
inferring exhaust flow rate
• Without depending on vehicle data stream
• Measure exhaust flow rate of moving vehicle
• Synchronizing exhaust flow rate and
concentration with changing speeds/loads
Instrumentation Size
• Portable gas analyzer with real-time comm.
Power requirement
• 12 volt equipment
8. Major Structural Problems Had to Be Overcome
No perceived need
• EPA ran FTPs
• Reducing standards without real-world feedback
thought to be effective
• Industry opposition
No budget for “science projects”
• Borrowed 5 gas analyzer from Snap-on
• Repurposed all other equipment except annubar
flow element
9. Goal: “Blind Testing” With Diagnostics
Measure mass emissions and distance traveled of
any arbitrary engine/vehicle “blind,” i.e. based
on primary measurements without needing:
• Any vehicle information, e.g. make and model
• Any vehicle speed or other sensor signal
• ECM data stream or OBD port data
Supplemental Diagnostics (secondary data)
• ECM data stream or OBD port data if desired
and available
• Enable diagnosing causes of emissions and fuel
economy issues seen with primary measurements
16. Rigorous Laboratory Comparison Program
Measured in Series With Lab System: single test on many
vehicles and many tests on single vehicle
17. Getting the Word Out to Others
Demos and presentations
• EPA Nat. Veh. Fuels and Emiss. Lab (NVFEL)
• Mobile Source Federal Advisory Committee
(FACA) – Mike Walsh, Chair
• Engine Manufacturers Association (EMA)
Loaned copies of systems for use:
• NESCAUM, CARB, Moscow, Vermont
Loaned copies for Correlation studies:
• West Virginia University (WVU)
• Southwest Research Institute (SwRI)
• Aberdeen Proving Grounds (APG)
Prominent role in DOJ investigations of 90’s
