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BG3 Partial Flow Diluter 

United States EPA Approval January 2011

The BG3 Partial Flow Dilution (PFD) technology has been in use since 2004 effectively performing engine research and development to accurately sample exhaust particulate matter emissions over both steady state and transient test cycles. On January 7, 2011, PFD was signed into law and is now included in the United States Federal Register as a legally recognized alternative method to CVS in 40 CFR part 1065 for engine certification. The Direct Final Rule (DFR) contains, among other things, the unprecedented allowance to use PFD for engine emissions particulate matter transient certification testing.

The Docket for the DFR shows that the basis for the US EPA decision was the correlation to FTP and NRTC CVS transient test cycle PM (particulate matter) demonstrated by Sierra-CP's BG3, as required by 40 CFR Part 1065.12. A 5-year program conducted in cooperation with the US EPA resulted in a BG3 vs CVS multiple engine, two-lab correlation study requiring the measurement of PM over a two-decade range in concentration levels. It was successfully performed to prove BG3 complies as a suitable, fully compliant alternative method to CVS for certification of engines tested on 2007 and Tier IV transient test cycles. This historical milestone opens the door to greater PM testing flexibility for all Heavy Duty (HD) as well as the Light Duty engine manufacturers requiring compliance to 40CFR Part 1065 test procedures. Access to all information posted on the US EPA website follows:

  • Direct Final Rule (Snapshot of Relevant Section Page 68452, Part D): Learn More...
  • Direct Final Rule (Complete Version), see Page 68452, Part D; See Footnote 14 to see reference to Sierra Learn More...
  • BG3 vs CVS multiple engine correlation study: Learn More...
  • Docket detailing DFR decision: Learn More...
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