UN R24 Supplement 8 (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 8 to the 03 series of amendments
Supplement 7 → 8
- What changed
- In Annex 4, the engine power tolerance at the other measurement points is now ± 4 per cent, not + 6 per cent and - 2 per cent.
- Annex 10, paragraph 4.7. now says "Depression in intake duct" instead of "Pressure in intake duct".
- Why
- The power tolerances are aligned with UN Regulation No. 85.
- The word "depression" makes clear that the measurement point is different between naturally aspirated and pressure charged engines.
Q1What changed3 changes
Engine power tolerance in the test at steady speeds (Annex 4, para. 3.1.5.)
In the test at steady speeds, the engine power measured at the test bench may differ from the power specified by the manufacturer. At the other measurement points, this difference may now be ± 4 per cent. Before this supplement, it was + 6 per cent and - 2 per cent. At maximum power, the tolerance is ± 2 per cent.
Depression in intake duct (Annex 10, para. 4.7.)
Annex 10, paragraph 4.7. now says "Depression in intake duct (see note 1a to table 1)". Before this supplement, it said "Pressure in intake duct".
Q2Why it changed
- Proposed by
- Expert from the International Organization of Motor Vehicle Manufacturers
- Working party
- GRPE, 85th session (January 2022)
Reasons
The power tolerances are aligned with UN Regulation No. 85: ± 2 per cent at maximum power and ± 4 per cent at the other measuring points.
Source
“Alignment with UN Regulation No. 85, i.e. ± 2 per cent at maximum power and ± 4 per cent at other measuring points”
The word "depression" is used for "alignment" with ISO 1585:2020. It makes clear that the measurement point is different between naturally aspirated and pressure charged engines.
Source
“"Alignment" with ISO 1585:2020, i.e. through usage of the word "depression" to clarify that the measurement point is different between naturally aspirated and pressure charged engines.”
Document trail
- 2021-10ProposalECE/TRANS/WP.29/GRPE/2022/4Proposal by the expert from OICA
- —Working party adoptsECE/TRANS/WP.29/GRPE/85GRPE session report, para. 35
- 2022-04Sent to WP.29ECE/TRANS/WP.29/2022/73Text that GRPE sent to WP.29 and AC.1
- 2022-06WP.29 adoptsECE/TRANS/WP.29/1166Adopted at the 187th session (session report, para. 182)
- 2023-01-04In forceC.N.468.2022.TREATIES-XI.B.16.24UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Check the engine power measured at the test bench in the test at steady speeds (Annex 4, para. 3.1.5.). At the other measurement points, it may differ from the power that you specify by ± 4 per cent.
- Update the documents that quote Annex 4, paragraph 3.1.5. or Annex 10, paragraph 4.7.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- In the test at steady speeds, apply ± 4 per cent at the other measurement points (Annex 4, para. 3.1.5.).
- Update your test procedures to say "Depression in intake duct" (Annex 10, para. 4.7.).
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ⓘ This report gives advice only. It is not legal or type-approval advice.