UN R49 Supplement 10 (06 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 10 to the 06 series of amendments

Supplement 9 → 10

Adopted at the WP.29 195th sessionEntry into force 2025-09-26

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What changed: PM number is no longer a pollutant to measure with PEMS (Annex 8, Appendix 1, paragraph A.1.1.).
Table 1 “Test parameters” no longer has the two rows with the PM number analyser as source (paragraph A.1.2.2.).
This supplement deletes paragraphs 10.1.9.24a. and 10.1.11.9bis. of Annex 8 on the CO2 mass window PM number conformity factor.
Why: Supplement 9 added some paragraphs by mistake to a part that does not exist in the 06 series.
OICA proposed to delete the PEMS PM number, which the 06 series does not require.

Q1What changed5 changes

PM number removed from the PEMS pollutant list (para. A.1.1.)

With PEMS, the pollutants to measure for compression ignition engines include carbon monoxide, total hydrocarbons and nitrogen oxides. For positive ignition engines, they include carbon monoxide, non-methane hydrocarbons, methane and nitrogen oxides. Before this supplement, both lists also included PM number. If all the fuels used have a molar carbon to hydrogen ratio of 0, the manufacturer may choose to measure only THC, CO and NOx. Before this supplement, this choice also included PM number.

This Appendix describes the procedure to determine pollutant emissions from on-vehicle on-road measurements using Portable Emissions Measurement Systems (hereinafter “PEMS”). The pollutant emissions to be measured from the exhaust of the engine include the following components: carbon monoxide, total hydrocarbons, and nitrogen oxides and PM number for compression ignition engines and carbon monoxide, non- methane hydrocarbons, methane, and nitrogen oxides and PM number for positive ignition engines. Additionally, carbon dioxide shall be measured to enable the calculation procedures described in paragraph A.1.4.

For engines where all the fuels used have a molar carbon to hydrogen ratio of 0 as defined in paragraph 8. of Annex 4, the manufacturer may choose to measure only the total hydrocarbon (THC), carbon monoxide (CO), ) and nitrogen oxides (NOx) and PM number. ). In this case lambda and optionally air mass flow shall be measured as well to enable the data consistency check as described in paragraph A.1.3.2.

PM number rows deleted from Table 1 (para. A.1.2.2.)

Table 1 “Test parameters” no longer has the row for PM number concentration (#/cm3). It also no longer has the row “Dilution setting (if applicable)”. The PM number analyser was the source for both rows.

PM number concentration #/cm3 PM number analyser Dilution setting (if applicable) - PM number analyser

CO2 mass window PM number conformity factor deleted (Annex 8, paras. 10.1.9.24a. and 10.1.11.9bis.)

Annex 8 no longer has paragraphs 10.1.9.24a. and 10.1.11.9bis. Both paragraphs listed the CO2 mass window PM number conformity factor. They applied to engines where none of the fuels used has a molar carbon to hydrogen ratio of 0. Annex 8 covers the conformity of in-service engines or vehicles.

CO2 mass window PM number conformity factor [-] for engines where none of the fuels used has a molar carbon to hydrogen ratio of 0 as defined in paragraph 8. of Annex 4.

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Q2Why it changed

Proposed by: Expert from France, with an addition from OICA
Working party: GRPE, 91st session (October 2024)

Reasons

Supplement 9 added some paragraphs by mistake to a part that does not exist in the 06 series. The proposal from France deletes these paragraphs, among them paragraphs 10.1.9.24a. and 10.1.11.9bis. of Annex 8.
Source
“Delete paragraphs that were mistakenly introduced in Supplement 9 to the 06 series of amendments to UN Regulation No. 49 to non-existing part of the 06 series of amendments to UN Regulation No. 49.”
ECE/TRANS/WP.29/GRPE/2024/21II. Justification, para. 1
In addition to the French proposal, OICA proposed to delete the PEMS PM number. An earlier amendment had added it, but the 06 series does not require it.
Source
“In addition to the French proposal, OICA proposes to delete the PEMS PM number as it had been added in previous amendment, which is not required by 06 series of Amendments to UN Regulation No. 49.”
ECE/TRANS/WP.29/GRPE/91Annex V, II. Justification, para. 2

Document trail

2024-07ProposalECE/TRANS/WP.29/GRPE/2024/21Proposal by the expert from France
—Amended in sessionGRPE-91-37Changes proposed by OICA
—Working party adoptsECE/TRANS/WP.29/GRPE/91Session report, para. 32 and Annex V
2024-12Sent to WP.29ECE/TRANS/WP.29/2025/26Text that GRPE sent to WP.29 and AC.1
2025-03WP.29 adoptsECE/TRANS/WP.29/1184Adopted at the 195th session (session report, para. 109)
2025-09-26In forceC.N.514.2025.TREATIES-XI.B.16.49UN depositary notification

Q3Who is affected

Vehicle manufacturer

Check that your PEMS test plans use the new pollutant list, which no longer includes PM number.
Check that your test set-up and data files match the new list of test parameters, without the PM number rows.
Update the documents that refer to paragraphs 10.1.9.24a. or 10.1.11.9bis. of Annex 8, which no longer exist.

Component supplier

If you supply PEMS equipment, check your set-up documents: PM number is no longer a pollutant to measure.

Technical service / Approval authority

Be ready for PEMS test results that do not include PM number.
Be ready for in-service conformity results under Annex 8 without the CO2 mass window PM number conformity factor.

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

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