§ 86.111-94 Exhaust gas analytical system.

Section 86.111-94 includes text that specifies requirements that differ from § 86.111-90. Where a paragraph in § 86.111-90 is identical and applicable to § 86.111-94, this may be indicated by specifying the corresponding paragraph and the statement “[Reserved]. For guidance see § 86.111-90.” Where a corresponding paragraph of § 86.111-90 is not applicable, this is indicated by the statement “[Reserved].”

(a) Schematic drawings. Figure B94-7 is a schematic drawing of the exhaust gas analytical system for samples from bag sampling systems for analysis of total hydrocarbon (THC) (hydrocarbon plus methanol in the case of methanol-fueled vehicles), methane (CH₄) (for vehicles subject to the NMHC and NMHCE standards), carbon monoxide (CO), carbon dioxide (CO₂), and oxides of nitrogen (NO_X). The schematic diagram of the continuous THC analysis train (and for THC plus methanol for methanol-fueled diesel-cycle vehicles) is shown as part of Figure B94-5 (or Figure B94-6). Since various configurations can produce accurate results, exact conformance with either drawing is not required. Additional components such as instruments, valves, solenoids, pumps, and switches may be used to provide additional information and coordinate the functions of the component systems.

(b) Major component description. The exhaust gas analytical system, Figure B94-7, consists of a flame ionization detector (FID) (heated, 235° ±15 °F (113° ±8 °C) for methanol-fueled vehicles) for the determination of THC, a methane analyzer (consisting of a gas chromatograph combined with a FID) for the determination of CH₄, non-dispersive infrared analyzers (NDIR) for the determination of CO and CO₂, a chemiluminescence analyzer (CL) for the determination of NO_X, and an analyzer meeting the requirements specified in 40 CFR 1065.275 for the determination of N₂O. A heated flame ionization detector (HFID) is used for the continuous determination of THC from petroleum-fueled diesel-cycle vehicles (may also be used with methanol-fueled diesel-cycle vehicles), Figure B94-5 (or B94-6). The analytical system for methanol consists of a gas chromatograph (GC) equipped with a flame ionization detector. The analysis for formaldehyde is performed using high-pressure liquid chromatography (HPLC) of 2,4-dinitrophenylhydrazine (DNPH) derivatives using ultraviolet (UV) detection. The exhaust gas analytical system shall conform to the following requirements: