[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.339-79]
[Page 611-612]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND
ENGINES--Table of Contents
Subpart D_Emission Regulations for New Gasoline-Fueled and Diesel-Fueled
Heavy-Duty Engines; Gaseous Exhaust Test Procedures
Sec. 86.339-79 Pre-test procedures.
(a) Allow a minimum of 30 minutes warm-up in the stand-by or
operating mode prior to spanning the analyzers.
(b) Replace or clean the filter elements and then vacuum leak check
the system, Sec. 86.328(a). A pressure leak check is also permitted per
Sec. 86.328(b). Allow the heated sample line, filters, and pumps to
reach operating temperature.
(c) Perform the following system checks:
(1) If a stainless steel NO2 to NO converter is used,
prior to gasoline-fueled engine tests, purge the converter with air
(zero-grade air, room air, or O2) for a minimum of 30
minutes. The converter must be at operational temperature while purging.
(2) Check the sample-line temperature (see Sec. 86.310).
(3) Check the system response time (see Sec. 86.329). System
response time may be applied from the most recent check of response time
if all of the following are met:
(i) The flow rate for each flow meter is equal to or greater than
the flow rate recorded in Sec. 86.329(b)(1)(ii).
(ii) For analyzers with capillaries, the response time from the
sample/span valve is measured using in-use pressures and bypass flows
(see Sec. 86.329(b)(2)).
(iii) The response time measured in step (ii) is equal to or less
than the response time determined in Sec. 86.329(b)(2)(vii).
(4) A hang-up check is permitted.
(5) A converter-efficiency check is permitted. The check need not
conform to Sec. 86.332(b). The test procedure may be aborted at this
point in the procedure in order to repair the NO2 to NO
converter. If the test is aborted, the converter must pass the
efficiency check described in Sec. 86.332(b) prior to starting the
dynamometer test run.
(d) Introduce the zero-grade gases at the same flow rates and
pressures used to calibrate the analyzers and zero the
[[Page 612]]
analyzers on the lowest anticipated range that will be used during the
test. Immediately prior to each test (segment, for Diesel engines),
obtain a stable zero for each anticipated range that will be used during
the test.
(e) Introduce span gases to the instruments under the same flow
conditions as were used for the zero gases. Adjust the instrument gains
on the lowest range that will be used to give the desired value. Span
gases should have a concentration greater than 70 percent of full scale
for each range used. Immediately prior to each test and also prior to
each segment of the Diesel test, record the response to the span gas and
the span-gas concentration for each range that will be used during the
test.
(f) Check the zero responses. If they have changed more than 0.5
percent of full scale, repeat paragraphs (d) and (e) of this section.
(g) Check system flow rates and pressures. Note the values of gauges
G3 and G4 for reference during the test.