TITLE 40 - PROTECTION OF ENVIRONMENT

CHAPTER I - ENVIRONMENTAL PROTECTION AGENCY

SUBCHAPTER U - AIR POLLUTION CONTROLS

PART 1065 - ENGINE - TESTING PROCEDURES

subpart c - MEASUREMENT INSTRUMENTS

1065.272 - Nondispersive ultraviolet analyzer.

  (a) Application. You may use a nondispersive ultraviolet (NDUV) analyzer to measure NOX concentration in raw or diluted exhaust for batch or continuous sampling. We generally accept an NDUV for NOX measurement, even though it measures only NO and NO2, since conventional engines and aftertreatment systems do not emit significant amounts of other NOX species. Measure other NOX species if required by the standard-setting part.

  (b) Component requirements. We recommend that you use an NDUV analyzer that meets the specifications in Table 1 of 1065.205. Note that your NDUV-based system must meet the verifications in 1065.372 and it must also meet the linearity verification in 1065.307. You may use a NDUV analyzer that has compensation algorithms that are functions of other gaseous measurements and the engine's known or assumed fuel properties.

The target value for any compensation algorithm is 0.0% (that is, no bias high and no bias low), regardless of the uncompensated signal's bias.

  (c) NO2-to-NO converter. If your NDUV analyzer measures only NO, place upstream of the NDUV analyzer an internal or external NO2-to-NO converter that meets the verification in 1065.378. Configure the converter with a bypass to facilitate this verification.

  (d) Humidity effects. You must maintain NDUV temperature to prevent aqueous condensation, unless you use one of the following configurations: (1) Connect an NDUV downstream of any dryer or chiller that is downstream of an NO2-to-NO converter that meets the verification in 1065.378.

  (2) Connect an NDUV downstream of any dryer or thermal chiller that meets the verification in 1065.376.

O2 Measurements