UN Regulation No. 85
Power Measurement of Internal Combustion Engines and Electric Motors

Series of Amendments, Supplements, and Corrigenda

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 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 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 (recognized in SAE J1349) 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.

Proposal to align UN R85 with ISO 1585:2020 and clarify the scope with regard to electric drive trains.

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