Proposal to amend UN GTR No. 21 on system power determination:

• Establish a globally harmonized test procedure comparable to traditional engine power ratings for conventional vehicles,
• specify TP1 based on measured electrical power and estimated internal combustion engine power with electrical conversion efficiency factors,
• specify TP2 based on measured torque and speed at axle shafts or wheel hubs with mechanical conversion efficiency factors,
• require manufacturers to provide verifiable K conversion factors,
• remove dynamometer roller measurement options for TP2 in favor of torque and speed sensors or hub dynamometers,
• mandate fuel flow rate measurement for TP1,
• introduce the reference point concept to ensure comparable results across powertrain architectures,
• require five test repetitions with averaging of the last four,
• add applicability guidelines limiting TP1 or TP2 to specific architectures based on power flow characteristics,
• establish approval criteria for system bench facilities as alternatives to chassis or hub dynamometers in a new Annex 3.