# Presentation: 423815

## EPA’s 2001-Published Heavy-Duty Diesel PM Test Procedure Changes

- Matthew Spears

- EPA’s Office of Transportation & Air Quality

## Introduction

- EPA made significant changes to 40 CFR Part 86, Subpart N as part of the 2007 Heavy-Duty Diesel Engine Regulation
- Worked closely with engine manufacturer’s experts in certification test procedures
- Available at: _[http://www.epa.gov/otaq/regs/hd2007/frm/frdslreg.pdf](http://www.epa.gov/otaq/regs/hd2007/frm/frdslreg.pdf)_

## §86.1306-07; Overview

- New test procedures may be implemented immediately
- Certain procedures must be used with others
- Application for approval of alternate procedures is now specified, including:
- Theoretical explanation
- Detailed description of any hardware and software
- Detailed description of any calibration, operation and maintenance procedures
- Statistical comparison of experimental results

## §86.1310-07; Analytical Systems

- Multiple sampling systems are allowed
- Recommended low thermal capacity dilution tunnel
- Recommended CVS mixing test
- Dilution air filtration is specified
- 98% efficient filtration for primary, HEPA for secondary
- Dilution air minimum temperature: 15C

## §86.1310-07; Analytical Systems

- Smaller PM probe allowed
- Double dilution is required for PM sampling
- Preclassifier required after double dilution
- 99% penetration at 1um, 50% cut at 2.5-10um
- ~47mm diameter filter diameter required
- High efficiency filter media required (e.g. TX-40, Teflo)
- Single filter cartridge and cartridge holder design specified
- Filter face temperature: 47 +-5 C

- SUB-SONIC VENTURI
- (SSV)

- (OPTIONAL FOR CFV, SSV)

- PARTICULATE PRE-CLASSIFIER
- OPTIONALLY HEATED

## §86.1312-07; Filter room

- More stringent temperature and dew point specifications
- 22+-3C (+-1C at microbalance), 9.5+-1C dewpoint
- More stringent reference filter weight change: 10ug
- More stringent microbalance performance specifications
- Require balance operator grounding to balance
- Specified electrostatic neutralizer performance
- Allowed repeat weighing and statistical analysis
- Required buoyancy correction
- Recommended vibration, electrostatic, and draft isolation of microbalance
- Recommended Class 1000 clean room conditions

## PM Filter Handling

## §86.1334-07; Preconditioning

- Added 20 minute steady-state high temperature preconditioning cycle

## §86.1337-07; Test Run

- No longer require engine detachment from CVS during hot soak

## Additional Guidance Given in 2002 “Dear EMA” Letter

- Worked closely with manufacturers and met on a monthly basis to understand mfr. needs
- Clarified a sound sequence to implement PM measurement changes incrementally
- Provided an improved statistical test for equivalent methods
- Provided approvable practices on
- PM measurement techniques
- Forced aftertreatment cool-down
- Subsonic Venturi calibration

## EPA’s Assessment of Current Measurement Variability

- Current variability does not limit laboratories at 2007 certification levels
- EPA has demonstrated this with 2007-level data
- Not via statistical or “thought” experiments
- Data not based on product literature on instrument performance
- Data not based on speculations on emissions dynamic range

## NOx Measurement

- Low NOx measurements agree well between bag and continuous analyzers
- EPA believes that today’s continuous measurement technique is viable for certification at 2007-levels

## Continuous versus Bag NOx Measurement Using Old Beckman 955

**Continuous versus Bag NOx Measurement Using Old Beckman 955**

- Comparison made on hot start HDD FTP.
- Dual path NOx adsorber system.

## Continuous versus Bag Measurement Using New Horiba CLA-720MA

- Comparison made on hot start HDD FTP.
- Dual path NOx adsorber system.

## PM Measurement

- Microbalance weighing is largest source of variability
- Current variability is only 25% of rounding allowance at the standard
- Repeat reference filter weights at +-1.5ug is achievable
- EPA results consistent with Ford and SwRI
- Indicates that 30-60 ug filter loading is sufficient

## PM Measurement Concern

## PM Measurement

## FTP PM Emissions For Engine Out and Post Traps

## FTP CVS Filter Weight Gain For Engine Out and Post Traps

## NMHC Measurement

- NMHC
- Have met standards using aftertreatment
- assuming NMHC = 0.98*THC
- Recent measurements indicate
- NMHC = ~0.5*THC
- Latest results are now less than 1⁄2 of the standard

## NMHC Measurement

## EPA’s Next Steps

- Ensure lab-to-lab variability is well-controlled
- Continue mfr. lab tours such as at EPA, SwRI, and CARB
- Continue to meet with manufacturers to ensure correct implementation of new test procedures
- Committed to pursuing improvements
- Implementing highly recommended a-b-a PM weighing
- Procuring state-of-the-art systems
- New low NOx diesel analyzers
- New 2007 PM measurement system
- New heated bag system for HC
- Low-loss dilution tunnel
- Supporting measurement research: CRC E-66
- Preparing Part 1065 for future application for on-highway