California Code of Regulations › Title 13 - Motor Vehicles › Division 3 - Air Resources Board › Chapter 14 - Verification Procedure, Warranty and in-Use Compliance Requirements for in-Use Strategies to Control Emissions from Diesel Engines › Section 2706 - Other Requirements

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a)
				Limit and Procedure for Measuring Nitrogen Dioxide
				(NO2).
(1) In order
				for a diesel emission control strategy to be verified, effective January 1,
				2007, the diesel emission control strategy must not increase emissions of
				NO2 by more than an increment equivalent in mass to 30
				percent of the baseline NOx emission level. Effective January 1, 2009, the
				increment is reduced to 20 percent of the baseline NOx emission level. The
				average of NO2 emission levels from both the initial and
				final emissions tests described in Section
				2704(g) is used
				to determine compliance with the NO2 limit. For chassis
				dynamometer testing, only the NO2 emission level over
				the UDDS cycle is used. The first NO2 emission limit
				takes effect beginning on January 1, 2007. Diesel emission control strategies
				verified and installed prior to January 1, 2007 are exempted from this
				requirement. Those verified prior to January 1, 2007 will no longer be allowed
				for installation after January 1, 2007 unless they meet the appropriate
				NO2 emission limit. After January 1, 2007, all diesel
				emission control strategies verified and installed must meet this
				requirement.
(2)
				NO2 emissions are to be quantified by one of the
				following methods:
(A) Two chemiluminescence
				analyzers,
(B) A dual-path
				chemiluminescence analyzer, or
(C)
				An alternative method approved by the Executive Officer.
(3) Analyzer configuration and determination
				of NO2 emission level. For (2)(A) and (2)(B), the
				analyzers are to be fed from a heated and conditioned sample path. If two
				chemiluminescence analyzers are employed, they are to be simultaneously fed
				from a common heated sample path. One instrument (or path) shall be set to NOx
				mode, while the second shall be set to nitric oxide (NO) mode. The instrument
				(or path) set to NOx mode receives a sample that has passed through an
				NO2-to-NO converter, and the resultant concentration is
				designated as total NOx (NO+NO2) in the sample. The
				instrument (or path) that is set to NO mode receives a sample that has not
				passed through the converter and quantifies the amount of NO only. The
				difference between NO and NOx is the amount of NO2 in
				the sample. Both NO and NOx signals are recorded by an external data
				acquisition system at 1 Hertz. Using the average concentrations of NO and NOx
				over the entire test cycle, the conventional equation for calculating total NOx
				(Code of Federal Regulations, Title 40, part 86, Subpart N) is then used to
				generate a gram per mile or g/bhp-hr value for both NO and NOx. The resulting
				value for NO is then subtracted from that for NOx to determine the gram per
				mile or g/bhp-hr value for NO2. The instrument for
				measuring NO and NOx must be calibrated in accordance with the NOx calibration
				procedure as described in the Code of Federal Regulations, Title 40, part 86,
				Subpart N.
(4) Pre-conditioning
				requirements. If the Executive Officer determines that a diesel emission
				control strategy has a propensity to increase emissions of
				NO2 and that NO2 emissions from a
				diesel emission control strategy could be affected by the presence of
				particulate matter or ash (as with a catalyzed diesel particulate filter), the
				strategy must be pre-conditioned according to the following procedure:
(A) Initial test (prior to service
				accumulation). Before conducting the initial emissions test, the unit being
				tested must be pre-conditioned as follows:
1.
				Install a new, unused unit on an engine that is an appropriate size for the
				unit, in a good state of maintenance, and certified to a PM standard equal to
				or more stringent than that of the engines in the emission control group for
				which the applicant seeks verification.
2. Operate the engine on one of the test
				cycles specified below for 25 to 30 hours. For on-road verifications, use
				either the FTP (hotstart) or UDDS cycle as identified in 2703(e), or the
				13-mode Supplemental Emissions Test (SET) in the Code of Federal Regulations,
				Title 40, Part 86. For off-road and stationary verifications, use either the
				steady-state test cycle or the Nonroad Composite Transient Cycle (NRTC)
				(California Code of Regulations, Title 13, section
				2423) from ARB off-road
				regulations. For up to 10 hours of the 25 to 30 hour period, beginning after at
				least the first three test cycle repetitions and ending before at least the
				last three test cycle repetitions, an applicant may alternatively:
a. Run the engine at high load such that the
				exhaust temperature is between 350 and 450 degrees Celsius, or
b. Alternate back and forth between high and
				low loads such that the exhaust temperature never exceeds 525 degrees Celsius
				and the low load operation does not result in significant soot accumulation at
				the end of the pre-conditioning period.
3. Measure and record the backpressure,
				exhaust temperature, date, and time on a second-by-second basis (1 Hertz) for
				the duration of the 25 to 30 hour pre-conditioning period.
4. Following the 25 to 30 hour period of
				operation, remove the unit from the pre-conditioning engine and install it on
				the emissions test engine, if applicable. Proceed with the initial emissions
				test and determine NO2i, as
				defined in section
				2706(a)(5).
				Determine the average backpressure over each of the emissions test repetitions
				and then average those values. The resulting average backpressure is compared
				with that of the aged unit per subsection (B), below.
(B) Final test (after the service
				accumulation). Before conducting the final emissions test, the aged unit may
				need to be pre-conditioned if the backpressure is too high. The applicant may
				either first perform the backpressure check described below or directly proceed
				with the final emissions test with the understanding that the test must be
				repeated if the backpressure is too high.
1.
				Backpressure check. Run one hot-start of the emissions test cycle with the aged
				unit installed on the emissions test engine. If using a chassis dynamometer,
				run the UDDS. Measure and record the backpressure on a second-by-second basis
				(1 Hertz) and determine the average. No pollutant measurements are necessary.
				Proceed with the emissions test as described in subsection (B)(3.) below if
				either the average backpressure is within 30 percent of the average
				backpressure recorded for the initial test unit or, for transient test cycles,
				the backpressure does not exceed 60 inches of water for more than two percent
				of the time, or, for steady-state test cycles, the backpressure never exceeds
				60 inches of water. Otherwise, pre-condition the aged unit as described in
				subsection (B)(2.) below.
2. If the
				backpressure of the aged unit does not comply with the appropriate criterion
				described in subsection (B)(1.) above, burn off excess soot or clean out excess
				ash as necessary. Run an additional repetition of the emissions test cycle
				(hot-start) to check if the unit complies with the backpressure criterion.
				Repeat as necessary.
3. Conduct
				emissions testing with the aged unit. Determine
				NO2f, as defined in section
				2706(a) (5.). If
				the backpressure does not comply with the appropriate criterion described in
				subsection (B)(1.) above, pre-condition the unit in accordance with subsection
				(B)(2.) and retest. If the backpressure check in subsection (B)(1.) was
				conducted prior to emissions testing and the unit was brought into compliance
				at that time, do not retest.
(C) In-use compliance testing. Before
				conducting in-use compliance emissions testing, the test units may need to be
				pre-conditioned. Using the required test cycle, measure and record the
				backpressure on a second-by-second basis (1 Hertz) over one hot-start test with
				a cleaned (or pre-conditioned per subsection (A) above) reference unit
				installed on the engine to be used for in-use compliance testing. The reference
				unit must be identical to the test units. Measure and record the backpressure
				of the test units retrieved from the field using the same engine and test cycle
				(one hot-start) as used with the reference unit. If the backpressure of a given
				test unit is either within 30 percent of the average backpressure recorded for
				the reference unit or, for transient test cycles, the backpressure does not
				exceed 60 inches of water for more than two percent of the time, or, for
				steady-state test cycles, the backpressure never exceeds 60 inches of water, it
				does not require pre-conditioning. Otherwise, the test units must be
				pre-conditioned following subsection (B) above. Other units may not be
				substituted for the selected test units.
(D) Determination of backpressure. The
				applicant must submit the actual recorded backpressure in an electronic format
				as measured on a second-by-second basis over each test run and over the 25 to
				30 hour pre-conditioning period. Prior to calculating the average backpressure
				over a given test run, however, any negative values caused by the draw of the
				dilution tunnel must first be zeroed.
(5) Determination of compliance with the
				NO2 limit. Compliance with the
				NO2 limit is based on the average incremental increase
				in NO2 emissions as determined by the following
				equation:
Percent Increase=100% x 0.5 x
				  [(NO2i -
				  NO2b)+(NO2f
				  - NO2b)] / NOxb
Where "NO2" and "NOx" stand for the
				  mass-based emission rates of NO2 and NOx, respectively,
				  as determined in subsection (a)(3) above, and the superscripts "i", "f", and
				  "b" stand for "initial test", "final test", and "baseline test", respectively.
				  For in-use compliance testing, the equation is:
Percent Increase=100% x (NO2
											c - NO2
											b) /
				  NOxb
Where the superscript "c" stands for the in-use compliance
				  emissions testing conducted with the unit installed on the test
				  engine.
(6) Alternative
				Method to Measure NO2. The applicant may request the
				Executive Officer to approve an alternative method in place of the required
				methods. In reviewing this request, the Executive Officer may consider all
				relevant information including, but not limited to, the following:
(A) Correlation of the alternative method
				with the methods stated in 2(A) or 2(B).
(B) Body of existing data generated using the
				alternative method.