UN R96 — Supplement 1 to the 05 series of amendments

New paragraph 3.1.1. applies to an application for type approval of engines operated solely on hydrogen. In this case, hydrogen must be the fuel the engine is designed to operate on primarily. Requirements for dual-fuel hydrogen engines have not yet been established under this Regulation. Unless it also meets paragraph A.4.4.2., the engine manufacturer must not indicate that engines may run on market fuels other than ISO 14687:2019 grade D. If the manufacturer permits engines to run on additional market fuels, such as other grades of hydrogen, paragraph A.4.4.2. lists three actions for the manufacturer. To receive a type approval of an engine operated solely on hydrogen, the manufacturer must comply with Annex 11 (para. A.4.4.3.).

Hydrogen is now item (g) in the list of reference fuels or fuel combinations in paragraph 5.1.3. New paragraph 3.3. of Annex 6 gives a table for the hydrogen reference fuel, with limits for the hydrogen fuel index and for non-hydrogen gases. The table gives values such as 99.97 % for the hydrogen fuel index and 300 μmol/mol for total non-hydrogen gases. Under note 6 to the table, the manufacturer must give the approval authority reasons for exempting specific contaminants. Paragraph 8.7.4. now refers to the reference fuels described in Annex 6 instead of Appendix 5. In Annex 10, the fuel type list of paragraph 2.4.6. now includes hydrogen as item (g).

New Annex 11 defines additional requirements and exceptions for emission testing of engines operated solely on hydrogen as specified in Appendix 4, paragraph A.4.4. Where Annex 11 lists no additional requirement or exception, this Regulation applies to these engines as to other approved engine types or engine families. The total mass of each gaseous constituent must be determined by continuous sampling from raw exhaust, without the dilution procedure of Annex 4, paragraph 9.2. The emissions calculation follows Annex 5, Appendix A.1 except as set out in paragraphs 8.1. to 8.5. of Annex 11. Item (d) of paragraph 5.6.4., paragraph 8.7.2.3. and Annex 4 now refer engines operated solely on hydrogen to Annex 11. The title of Annex 5 now limits it to engines other than those operated solely on hydrogen.

Under paragraphs 6.1.4. and A.5.6., manufacturers of engines operated solely on hydrogen (Appendix 4, para. A.4.4.) need not give the OEM a CO2 emission value. In this case, the OEM must give the end-user the statement that a CO2 emission value has not been declared (para. A.5.6.). For all other engines, the manufacturer must still make this value available to the OEMs. In Annex 4, CO2 emission values must be measured and reported for all engine sub-categories “where required” by paragraph 6.1.4., instead of “as required”. New notes 5 and (7) in Annex 2 mark CO2 entries as not mandatory for engines operated solely on hydrogen (Appendix 4, para. A.4.4.). In the test report, paragraphs 10.3.1. and 10.3.4. now read “Cycle weighted CO2 (g/kWh)”, instead of “Hot cycle CO2 (g/kWh)” and “Cycle CO2 for hot start test (g)”.

In Annex 1, Appendix A.3, paragraphs 2.8.1. and 3.14.1. now list hydrogen, and so does paragraph 2.8.1. of Annex 2, Part A. In the Annex 2, Appendix A.1 test report, new paragraph 4.5. asks for the make and type of the hydrogen reference fuel. The dual-fuel engine entries 4.5. and 4.5.1. are now numbered 4.6. and 4.6.1. Table 2 in Annex 3, Appendix A.1 adds fuel type codes for engines solely fuelled on hydrogen. The codes are T and TD for SI and CI engines calibrated for gaseous hydrogen, and U and UD for liquified hydrogen.

Paragraph 8.1.9.2.3. adds “or 20ppm, whichever is larger” to the ±2 per cent limit for combined H2O and CO2 interference of a CO NDIR analyser. Paragraph 9.4.10. now requires mounting the sensor directly on the exhaust pipe where the exhaust gas temperature is high enough to eliminate water condensation. The sensor with incorporated electronics must meet accuracy limits of ±3%, ±5% and ±10% of reading for three ranges of λ. The sensor must be calibrated as specified by the instrument manufacturer to fulfil this accuracy. In Annex 5, Appendix A.1, paragraph A.1.1.3. now says that Equations (A.5-4) and (A.5-7) are not applicable if water injection is used. In paragraph A.1.1.6.3., the definition of λi now reads “instantaneous excess air ratio calculated by Equation (A.5-19) or measured by a lambda sensor”.

Paragraph 1.1.3. now reads “Spark Ignition (SI)” instead of “Aprak Ignition (SI)”. Item (b) of paragraph 5.1.1.1. now reads “specified” instead of “specifiend”. A new RegVault Note says that ECE/TRANS/WP.29/2024/52 amends “paragraph 5.1.1.” with a text numbered 5.1.1.1., and that the amendment is applied to paragraph 5.1.1.1. Items (f) “Ethanol” and (d) “Particle number, PN” now end with “;” instead of “.”. Explanatory note 1 to Annex 2 now refers to document ECE/TRANS/WP.29/78/Rev.7 instead of Rev.6.