UN R49 — Supplement 3 to the 07 series of amendments

Paragraph 3.5.1. now includes dual-fuel engines of Type 1A with hydrogen as gaseous fuel. Requirements for all other types of dual-fuel hydrogen engines are not yet established. Before this supplement, paragraph 3.5.1. said that requirements for dual-fuel hydrogen engines were not yet established. In the approval mark of dual-fuel engines, the letter(s) after the two digits can now be those of paragraph 4.12.3.3.8. in case of hydrogen. Paragraph 4.2.2.3. of Annex 15 on repair and maintenance now names LNG or hydrogen Type A dual-fuel engines and vehicles. Before this supplement, it named LNG Type A dual-fuel engines and vehicles.

For dual-fuel engines of Type 1A with hydrogen as main fuel, separate CH4 and NMHC measurement is not mandatory; THC must be measured instead. The THC emission limit in paragraph 5.3. of this Regulation applies. Type 1A dual-fuel hydrogen engines must use method (a) of paragraph 7.1.3. of Annex 4 (raw gaseous/partial flow measurement). For Type 1A dual-fuel hydrogen engines, the CO2 emissions from fuel (equation 24) are based on the diesel fuel consumption only. Equation 24 now includes β, the molar carbon ratio of the fuel. For the dry/wet correction of Type 1A dual-fuel hydrogen engines, Equation 15a of Annex 4 replaces Equations 15 and 17.

For dual-fuel engines of Type 1A with hydrogen as main fuel, separate CH4 and NMHC measurement is not mandatory; THC must be measured instead. For the conformity factors, the applicable limit is then the THC emission limit only. For the same engines, lambda and optionally air mass flow must also be measured for the data consistency check. If one fuel used has a molar carbon to hydrogen ratio of 0, the consistency check uses the formula of Annex 4, paragraph 8.4.1.6. Before this supplement, this applied if all the fuels used had that ratio. For Type 1A dual-fuel hydrogen engines, the moving averaging window must use the reference work, not the CO2 mass based method.

New paragraph A.1.2.1.6. adds a connection with the vehicle OBFCM device, if applicable. Table 1 adds rows with “OBFCM device or ECU (if applicable)” as source, for example total fuel consumed, total distance travelled and vehicle total mass. Table 1 also adds a row for H2O concentration, with a gas analyzer as source. Where applicable, the recording of the Table 1 parameters from the OBFCM device starts at the test start and ends at the test end. New paragraphs 10.1.8a. and 10.1.10a. of Annex 8 list OBFCM instantaneous measured data and OBFCM values, if applicable. New point (k) of paragraph A.1.5.1. in Annex 10, Appendix 1 covers information about these OBFCM values.

When CO, CO2, CH4 or NOx is measured from raw exhaust, FTIR or QCL-IR analyzers may be used as an alternative. For FTIR and laser infrared analyzers, the instrument manufacturer must declare the expected interferences in an “Analyzer compliance declaration”. The analyzer type must be type-examined by an international or national metrological institute. The analyzer manufacturer must check interference effects before market introduction, at least once for each analyzer type in paragraph 9.3.2., except paragraph 9.3.2.7. The new FTIR and QCL-IR interference checks require a combined interference below 2 per cent of the measured value or 2 ppm, whichever is larger. The accuracy limits for “the sensor with incorporated electronics” by λ range are deleted.

New Appendix 9 to Annex 4 gives the procedure for the measurement of water (H2O). The analyzer used for H2O measurement must meet the criteria in paragraph A.9.2.2., and must be calibrated with an accurately humidified gas. If raw exhaust measurement is used, CO2, CH4 and H2O (if applicable) must now also be measured continuously and stored with at least 2 Hz. HC, NH3 and H2O must be measured wet, and gas dryers are not permitted for H2O and NH3 measurement. For hydrogen fuelled engines, new equation 15a uses the H2O concentration for the dry/wet correction. Paragraph A.5.2. changes the molar mass of dry air from 28.965 to 28.96559 g/mol and adds the molar mass of methane, 16.0425 g/mol.

The equivalent approval in paragraph 1.2. no longer requires that the approval to UN Regulation No. 83 or No. 154 was granted as an extension. Engines mounted in vehicles of up to 2,840 kg reference mass with such an approval do not need to be approved according to this Regulation.