UN R24 Supplement 11 (03 series) · UNECE Regulation No. 24 (ECE R24) — Uniform provisions concerning: I. The approval of compression ignition (C.I.) engines with regard to the emission of visible pollutants II. The approval of motor vehicles with regard to the installation of C.I. engines of an approved type III. The approval of motor vehicles equipped with C.I. engines with regard to the emission of visible pollutants by the engine IV. The measurement of power of C.I. engine.
UN R24 — Supplement 11 to the 03 series of amendments
Supplement 10 → 11
- What changed
- Annex 4, paragraph 3.2. now requires the reference fuel given in Annex 6, not the fuel available on the market.
- New paragraph 1.5. of Annex 5 requires commercially available fuel, and the reference fuel in any case of dispute.
- Annex 10, paragraph 9.1. now gives separate tolerances: ± 2 per cent for maximum power and ± 4 per cent at the other measurement points.
- Why
- Annex 5 still lacked clarity on the fuels that may be used, so the new paragraph makes Annex 5 consistent with Annex 4.
- The earlier text referred to emission testing according to UN Regulation No. 85, but R 85 is not emissions legislation.
- The tolerances in Annex 10 are aligned with UN Regulation No. 85.
Q1What changed6 changes
Fuel for the free acceleration test of an engine not run in (para. 8.3.1.)
On the request of the manufacturer, the reference fuel may now be used rather than commercially available fuel. Before this supplement, the manufacturer could request commercially available fuel rather than the reference fuel.
Fuel for the test at steady speeds (Annex 4, para. 3.2.)
Annex 4, paragraph 3.2. now says that the fuel must be the reference fuel whose specifications are given in Annex 6. Before this supplement, the fuel used had to be the one available on the market, and the reference fuel applied in any case of dispute. The paragraph now names testing for Engine Power to UN Regulation No. 85 and/or emission testing to UN Regulation No. 49. If such testing is done together with this test, the emission test fuel may be used at the request of the manufacturer. Before this supplement, the paragraph named emission testing to UN Regulations Nos. 85 and/or 49. In that case, the reference fuel for emission testing could be used at the request of the manufacturer.
New fuel paragraph for the test under free acceleration (Annex 5, para. 1.5.)
New paragraph 1.5. of Annex 5 says that the fuel used must be commercially available. In any case of dispute, the fuel must be the reference fuel whose specifications are given in Annex 6.
Tolerances for the net power (Annex 10, para. 9.1.)
The net power indicated by the manufacturer is compared with the values measured by the technical service. It must be accepted if it does not differ by more than ± 2 per cent for maximum power. At the other measurement points on the curve, the limit is ± 4 per cent. The tolerance for engine speed is ± 2 per cent. The text also says “or within the engine speed range (X1 min-1 - 2 per cent) to (X2 min-1 +2 per cent) (X1 < X2)”. Before this supplement, the measured net power could differ by ± 2 per cent, with a tolerance of 1.5 per cent for the engine speed.
Q2Why it changed
- Proposed by
- International Organization of Motor Vehicle Manufacturers
- Working party
- GRPE, 89th session (May–June 2023)
Reasons
The wording at the end of paragraph 8.3.1. is reversed to reflect the new wording proposed in Annex 5.
Source
“The wording at the end of paragraph 8.3.1. should be reversed to reflect the new wording proposed in Annex 5.”
Recent amendments tried to clarify the fuels that may be used for the various stages of approval. This clarity was still absent from Annex 5 (free acceleration test). The new paragraph makes Annex 5 consistent with Annex 4.
Sources (2)
“Recent amendments have attempted to clarify the fuels which may be used for the various stages of approval but it has since been noticed that this clarity is still absent from Annex 5 (free acceleration test).”
“This new paragraph therefore makes Annex 5 consistent with Annex 4.”
An amendment adopted at GRPE 86 in June 2022 allowed harmonised reference fuels. That text referred to testing for emission of gaseous and particulate pollutants and to UN Regulations Nos. 85 and/or 49. This was a contradiction, because R 85 is not emissions legislation. GRPE 87 adopted a similar amendment to Regulation 85 in January 2023, and this proposal seeks to bring consistency.
Sources (3)
“An amendment was adopted at GRPE 86 in June 2022 to introduce the allowance of harmonised reference fuels.”
“Sadly however the text contained a contradiction between the words “testing for emission of gaseous and particulate pollutants” and the references to “UN Regulations Nos. 85 and/or 49” as R 85 is not emissions legislation.”
“GRPE 87 discussed and adopted a similar amendment to Regulation 85 (GRPE-2022-08e as amended by GRPE-87-16e) in January 2023 and this proposal seeks to bring consistency.”
The tolerances are aligned with UN Regulation No. 85, that is ± 2 per cent at maximum power and ± 4 per cent at other measuring points. Supplement 8 considered this only for Annex 4 and not for Annex 10.
Sources (2)
“Alignment with UN Regulation No. 85, i.e. ± 2 per cent at maximum power and ± 4 per cent at other measuring points.”
“Supplement 8 considered this only for Annex 4 (TEST AT STEADY SPEEDS OVER THE FULL-LOAD CURVE) and not for Annex 10”
The wording “commercially available fuel” and the wording “fuel available on the market” were not consistent.
Source
“The wording is inconsistent “commercially available fuel” vs “fuel available on the market”.”
Document trail
- 2023-03ProposalECE/TRANS/WP.29/GRPE/2023/18Proposal by the International Organization of Motor Vehicle Manufacturers
- —Amended in sessionGRPE-89-18Amendments to the proposal by the experts from OICA
- —Working party adoptsECE/TRANS/WP.29/GRPE/89GRPE session report, para. 46 and Annex IV
- 2023-09Sent to WP.29ECE/TRANS/WP.29/2023/126Text that GRPE sent to WP.29 and AC.1
- 2023-11WP.29 adoptsECE/TRANS/WP.29/1175Adopted at the 191st session (session report, para. 180)
- 2024-06-15In forceC.N.239.2024.TREATIES-XI.B.16.24UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Be ready for the test at steady speeds with the reference fuel given in Annex 6 (Annex 4).
- With simultaneous testing to Regulation No. 85 and/or No. 49, decide if you request the emission test fuel (Annex 4).
- For the free acceleration test of an engine not run in, decide if you request the reference fuel (para. 8.3.1.).
- Make sure that the net power you indicate is within the tolerances of Annex 10, paragraph 9.1.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- Check that the test at steady speeds uses the reference fuel given in Annex 6 (Annex 4).
- For the test under free acceleration, check that the fuel used is commercially available (Annex 5, para. 1.5.).
- In any case of dispute, check that the fuel is the reference fuel of Annex 6 (Annex 5, para. 1.5.).
- Compare the net power indicated by the manufacturer with your measured values, with the tolerances in Annex 10, paragraph 9.1.
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ⓘ This report gives advice only. It is not legal or type-approval advice.