CFR > Title 40 - Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS (Parts 50–99) > PART 86—CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES > SUBPART D—Emission Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures (§86.301-79 to §86.348-79) > 86.317-79—Hydrocarbon analyzer specifications.

86.317-79—Hydrocarbon analyzer specifications.

(a) Hydrocarbon measurements are to be made with a heated flame ionization detector (HFID) analyzer.
(b) Option. A non-heated flame ionization detector (FID) that measures hydrocarbon emissions on a dry basis is permitted for gasoline-fueled testing; Provided, That equivalency is demonstrated to the Administrator. With the exception of temperatures, all specifications contained in subpart D apply to the optional system.
(c) The analyzer shall be fitted with a constant temperature oven housing the detector and sample-handling components. It shall maintain temperature with 2 °C of the set point. The detector, oven, and sample-handling components within the oven shall be suitable for continuous operation at temperatures to 200 °C.
(d) Fuel and burner air shall conform to the specifications in § 86.308.
(e) The percent of oxygen interference must be less than 3 percent, as specified in § 86.331(d)(7).
(f) Premixed burner air:
(1) For Diesel engines, premixing a small amount of air with the HFID fuel prior to combustion within the HFID burner is not recommended as a means of improving oxygen interference (%O2 I). However, this procedure may be used if the engine manufacturer demonstrates on each basic combustion system (i.e., 4 cycle DI, 2 cycle DI, 4 cycle precup, etc.) that an HFID using this procedure produces comparable results to an HFID not using this procedure. These data must be submitted to the Administrator for his approval prior to testing.
(2) For gasoline-fueled engines, premixing burner air with the HFID fuel is not allowed.