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UN R49 Supplement 11 (05 series) · UNECE Regulation No. 49 (ECE R49) — Uniform provisions concerning the measures to be taken against the emission of gaseous and particulate pollutants from compression-ignition engines and positive ignition engines for use in vehicles.

UN R49 — Supplement 11 to the 05 series of amendments

Supplement 10 → 11

Adopted at the WP.29 185th sessionEntry into force 2022-06-22
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What changed
  • Table 7 of Annex 4B has a new linearity row for the humidity measurement device.
  • A new entry “Hydrogen mixture (FID burner fuel)” in Annex 4A, Appendix 5, paragraph 1.2.1. gives nitrogen as an alternative to helium.
  • For the saturation vapour pressure, new text says that equation D.15 specified in Annex D to ISO Standard 8178-4:2020 should be used.
Why
  • The proposal states that Regulation 49 defines no linearity requirements for humidity sensors.
  • The representative from OICA explained that helium is now difficult and expensive to acquire.
  • The change to paragraph 1.7.2. aims to clarify the operation procedure, and the change to paragraph 1.7.8. corrects a typing error.

Q1What changed14 changes

Saturation vapour pressure in humidity calculations (Annex 4B, para. 8.2.; Annex 4A, Appendix 1, para. 5.3.)

A new paragraph is added to Annex 4B, paragraph 8.2., and to Annex 4A, Appendix 1, paragraph 5.3. It says that all humidity calculations (for example Ha, Hd) using generally accepted equations require the saturation vapour pressure. To calculate the saturation vapour pressure, the equation D.15 specified in Annex D to ISO Standard 8178-4:2020 should be used.

For all humidity calculations (for example Ha, Hd) using generally accepted equations the saturation vapour pressure is required. For calculating the saturation vapour pressure which is in general a function of the temperature (at the humidity measurement point) the equation D.15 specified in Annex D to ISO Standard 8178-4:2020 should be used.
For all humidity calculations (for example Ha, Hd) using generally accepted equations the saturation vapour pressure is required. For calculating the saturation vapour pressure which is in general a function of the temperature (at the humidity measurement point) the equation D.15 specified in Annex D to ISO Standard 8178-4:2020 should be used.

Linearity requirements for the humidity measurement device (Annex 4B, para. 9.2., Table 7)

Table 7 “Linearity requirements of instruments and measurement systems” has a new last row for the humidity measurement device. The row gives the values ≤ 2 % max., 0.98 – 1.02, ≤ 2 % and ≥ 0.95. Before this supplement, Table 7 had no row for a humidity measurement device.

Humidity measurement device ≤ 2 % max. 0.98 – 1.02 ≤ 2 % ≥ 0.95

Hydrogen mixture as FID burner fuel (Annex 4A, Appendix 5, para. 1.2.1.)

The heading of paragraph 1.2.1. is now “Pure gas” instead of “Pure Gases”. Paragraph 1.2.1. now has the entry “Hydrogen mixture (FID burner fuel)”. The mixture is 40 ± 1 per cent hydrogen, balance helium or alternatively nitrogen. Its contamination limits are ≤ 1 ppm C1 and ≤ 400 ppm CO2.

Pure Gasesgas
Hydrogen mixture (FID burner fuel)
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Calibration and NOx mode steps (Annex 4A, Appendix 5, paras. 1.7.2. and 1.7.8.)

Paragraph 1.7.2. now says that, with the ozonator deactivated, the NOx analyzer must be in the NO mode. The rest of that sentence, “so that the span gas does not pass through the converter”, does not change. The heading of paragraph 1.7.8. is now “NOx mode” instead of “NO mode”. Its text now starts with “Keeping NOx mode with the ozonator deactivated” instead of “Switched to NO mode with the ozonator deactivated”. The words in brackets at the end now say “the analyzer is in the NOx mode”. The ±5 per cent limit does not change.

The CLD and the HCLD shall be calibrated in the most common operating range following the manufacturer's specifications using zero and span gas (the NO content of which shall amount to about 80 per cent of the operating range and the NO2 concentration of the gas mixture to less than 5 per cent of the NO concentration). The With the ozonator deactivated, the NOx analyzer shall be in the NO mode so that the span gas does not pass through the converter. The indicated concentration has to be recorded.
NO NOx mode
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Capital letters and multiplication signs (Annex 4A, Appendix 1, para. 5.3.)

In paragraph 5.3., “with:” is now “With:”, and “where:” is now “Where:” in two places. The formula for spark ignition engines now shows the multiplication signs: kh.G = 0.6272 + 44.030 × 10-3 × Ha – 0.862 × 10-3 × Ha². The values in the formula do not change.

withWith:
whereWhere:
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Q2Why it changed

Proposed by
Expert from the International Organization of Motor Vehicle Manufacturers (OICA)
Working party
GRPE, 83rd session (June 2021)

Reasons

  • The proposal states that Regulation 49 defines no linearity requirements for humidity sensors. The humidity content of the intake air is an essential measure for the calculation of the specific exhaust emission.

    Sources (2)
    “Regulation 49 defines no linearity requirements for humidity sensors.”
    “As the humidity content of the intake air is an essential measure for the calculation of the specific exhaust emission”

  • The representative from OICA explained that helium is now difficult and expensive to acquire. This was the main reason to request an alternative option to measure hydrocarbons. The annual fluctuations of the global helium market lead to an insufficient supply of FID fuel gas.

    Sources (3)
    “The representative from OICA further explained that helium is now difficult and expensive to acquire as the main reason to request for an alternative option to measure hydrocarbons.”
    “The annual fluctuations of the helium global market lead to an insufficient supply with FID fuel gas”
    “Same reasoning as previous for Annex 4B, paragraph 9.3.3.1.”

  • The change to paragraph 1.7.2. is to clarify the operation procedure and to make the text easier to understand.

    Source
    “To clarify the operation procedure, make the text easier to be understood.”

  • The change to paragraph 1.7.8. corrects a typing error. The instrument should now be in NOx mode.

    Source
    “Typo error, the instrument should be now in NOx mode.”

  • For the change to Annex 4B, paragraph 8.2., the reasoning comes from experience. The need for the amendment was raised by technical service.

    Source
    “The reasoning is derived from the experience, and the need for the amendment has been raised by technical service.”

Document trail

  1. 2021-03ProposalECE/TRANS/WP.29/GRPE/2021/13Proposal by the expert from OICA
  2. —Working party adoptsECE/TRANS/WP.29/GRPE/83Session report, para. 22, with the changes in Annex IX
  3. 2021-09Sent to WP.29ECE/TRANS/WP.29/2021/129Text that GRPE sent to WP.29 and AC.1
  4. 2021-11WP.29 adoptsECE/TRANS/WP.29/1161Adopted at the 185th session (session report, para. 121)
  5. 2022-06-22In forceC.N.209.2022.TREATIES-XI.B.16.49UN depositary notification

Q3Who is affected

Vehicle manufacturer

  • Make sure that the humidity measurement device used for the tests meets the new linearity row in Annex 4B.
  • Compare your saturation vapour pressure calculation with equation D.15 of ISO Standard 8178-4:2020.
  • For FID burner fuel with nitrogen, make sure that the mixture is 40 ± 1 per cent hydrogen.
  • Update your converter efficiency test steps to the new text of paragraphs 1.7.2. and 1.7.8.

Component supplier

  • No direct action for this role.

Technical service / Approval authority

  • Check the humidity measurement device against the new linearity row in Annex 4B.
  • Be ready for FID burner fuel with nitrogen instead of helium as the balance gas (paragraph 1.2.1.).
  • When you test the efficiency of the converter, apply the new text of paragraphs 1.7.2. and 1.7.8.

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ⓘ This report gives advice only. It is not legal or type-approval advice.

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