The purpose of this proposal is to adjust the engine power-measurement calculation for supercharged and turbocharged engines fitted with a system that compensates for ambient conditions such as temperature and altitude. The proposed change would eliminate redundant correction factors that result in inaccurate results for these engine configurations.

Proposal to avoid a redundant correction of the measured engine power of supercharged and turbocharged engines fitted with a self-correcting system for ambient conditions such as temperature and altitude. The current correction factor may yield inaccurate results for such configurations.

Proposal to correct an error in the formula presented in paragraph 5.4.2. Diesel engines – Factor αd. The parameter “f_m” in the equation should be a superscript (e.g., meaning “to the power of f_m”). Through a transcription error, this factor was rendered in normal text.

Proposal to clarify the wording of the determination of the net power for electric motors and to correct an error in the formula presented in paragraph 5.4.2. Diesel engines – Factor αd. The parameter “f_m” in the equation should be a superscript (e.g., meaning “to the power of f_m”). Through a transcription error, this factor was rendered in normal text.

Revised proposal, superseding document GRPE/2018/5, to clarify the wording of the determination of the net power for electric motors and to correct an error in the formula presented in paragraph 5.4.2. Diesel engines – Factor αd. The parameter “f_m” in the equation should be a superscript (e.g., meaning “to the power of f_m”). Through a transcription error, this factor was rendered in normal text.

Proposal to introduce an alternative test method for measuring charge-air-cooled engines net power for use with high power engines of those. The proposal would “decrease the charge air cooler outlet temperature by the same amount that the ambient conditions for the vehicle test varied from the standard temperature” in line with SAE J1349, “9.3 Application of Vehicle Transient Data to Net Power Test.”

Explanation of the proposal (GRPE/2018/19) to align UN R24 (Compression Ignition Engines – Emission of Visible Pollutants – Power Measurement) with UN R85 with regard to correction factors.

Proposal to reduce testing burdens by introducing an alternative test method to “decrease the charge air cooler outlet temperature by the same amount that the ambient conditions for the vehicle test varied from the standard temperature.” This aligns with SAE J1349, “9.3 Application of Vehicle Transient Data to Net Power Test.”

Proposal to allow an alternative test method to “set the charge air cooler outlet temperature during bench test to temperature which was observed by vehicle test and corrected to the reference temperature specified in paragraph 5.2.1.” of Annex 5. This alternative method is well recognized in SAE J1349.

Proposal to allow an alternative test method to “set the charge air cooler outlet temperature during bench test to temperature which was observed by vehicle test and corrected to the reference temperature specified in paragraph 5.2.1.” of Annex 5. This alternative method is well recognized in SAE J1349.

Proposal to permit the usage of the gaseous reference fuels described in UN Regulation No. 83 in order to reduce potential testing complexity.

Proposal to permit the use of the gaseous reference fuels described in UN R83 in order to reduce potential testing complexity.

Proposal to align UN R85 with ISO 1585:2020.

Proposal to clarify the scope of Regulation 85 concerning electric drivetrains.

Proposal to permit the use of hydrogen (H2) as fuel for type approval of heavy-duty vehicles.

The use of test fuels is permitted for certification testing of gaseous and particulate pollutants and power/smoke testing in Europe. However, other countries that have adopted and referenced UN R85 may not allow this. This proposal would permit the use of the same test fuel in cases where the testing for emission of gaseous and particulate pollutants is conducted at the same time as the testing under UN R85.

Proposal to allow for the use of hydrogen (H2) as fuel for type approval of heavy-duty vehicles.

Proposal to explicitly permit the usage of the reference fuel required for emission testing when the manufacturer applies for
UN R24 and/or R49 type approval at same time.

Also applicable for R85

Proposal to permit the use of hydrogen (H2) as fuel for type approval of heavy-duty vehicles and to explicitly permit the usage of the reference fuel required for emission testing when the manufacturer applies for UN Regulations Nos. 24 and / or 49 type approval at same time.

Proposal to promote harmonisation in use of reference fuels for testing, including hydrogen fuel, based on the following justifications:

1. The use of test fuels is permitted for certification testing of gaseous and particulate pollutants and power/smoke testing in Europe. However, other countries that have adopted and referenced UN R85 may not allow this. In this case, manufacturers have to prepare fuels with different characteristics, which is costly and requires a long time due to the current inconsistent situation.
2. We believe that the use of test fuels for gaseous and particulate pollutant measurement tests should be a priority as a precondition for the introduction of more stringent emission levels.
3. Hydrogen fuelled vehicles are covered in UN Regulation No. 83, but hydrogen is not yet covered in UN R49 and UN R85.
4. Hydrogen fuelled engines could be one complementary option to reduce CO₂ emissions of future heavy-duty vehicles.
5. Therefore, hydrogen fuel should be integrated in UN R49 and UN R85 for better alignment with UN R83.

Background on changes proposed to UN R49 and UN R85 to address hydrogen fuel and heavy vehicles.

Proposal to clarify and update requirements for fitment of auxiliaries when testing the net power or 30 minutes power of electric drive trains.