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Sierra BG3 partial flow system a legal alternative to CVS

6 April 2011

Sierra Instruments announced that, as demonstrated in testing with Sierra’s BG®3, the US EPA has recognized partial flow dilution (PFD) technology as a legal alternative method to constant volume sampling (CVS) for 40 CFR part 1065 engine certification testing. The EPA direct final rule (DFR), published on November 8, 2010, became effective on January 7, 2011. Among other provisions, the rule allows the use of PFD systems for engine certification testing of PM emissions under transient conditions.

The BG3 PFD technology has been in use since 2003 for sampling exhaust PM emissions over both steady-state and transient test cycles in engine R&D applications.

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, as required by 40 CFR Part 1065.12 and demonstrated by Sierra’s BG3. A nearly 5-year program in cooperation with the US EPA resulted in a BG3 vs CVS multiple engine, two-lab correlation study that included testing over US EPA 2007 and Tier 4 transient test cycles.

The Sierra BG3 is a widely used PFD technology and boasts an installed base of hundreds of units globally. Benefits of using the BG3, according to Sierra, include: