[Code of Federal Regulations]

[Title 40, Volume 31]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR1065.270]



[Page 709]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents

 

                    Subpart C_Measurement Instruments

 

Sec.  1065.270  Chemiluminescent detector.



    (a) Application. You may use a chemiluminescent detector (CLD) to 

measure NOX concentration in raw or diluted exhaust for batch 

or continuous sampling. We generally accept a CLD for NOX 

measurement, even though it measures only NO and NO2, when 

coupled with an NO2-to-NO converter, since conventional 

engines and aftertreatment systems do not emit significant amounts of 

NOX species other than NO and NO2. Measure other 

NOX species if required by the standard-setting part. While 

you may also use other instruments to measure NOX, as 

described in Sec.  1065.272, use a reference procedure based on a 

chemiluminescent detector for comparison with any proposed alternate 

measurement procedure under Sec.  1065.10.

    (b) Component requirements. We recommend that you use a CLD that 

meets the specifications in Table 1 of Sec.  1065.205. Note that your 

CLD-based system must meet the quench verification in Sec.  1065.370 and 

it must also meet the linearity verification in Sec.  1065.307. You may 

use a heated or unheated CLD, and you may use a CLD that operates at 

atmospheric pressure or under a vacuum. You may use a CLD 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. Place upstream of the CLD an internal or 

external NO2-to-NO converter that meets the verification in 

Sec.  1065.378. Configure the converter with a bypass to facilitate this 

verification.

    (d) Humidity effects. You must maintain all CLD temperatures to 

prevent aqueous condensation. To remove humidity from a sample upstream 

of a CLD, use one of the following configurations:

    (1) Connect a CLD downstream of any dryer or chiller that is 

downstream of an NO2-to-NO converter that meets the 

verification in Sec.  1065.378.

    (2) Connect a CLD downstream of any dryer or thermal chiller that 

meets the verification in Sec.  1065.376.

    (e) Response time. You may use a heated CLD to improve CLD response 

time.