1. Draft
Dyno requirements for GTR (proposal broadly as per CFR § )
WLTP-DTP-LabProcICE-045 Dyno requirements
Item
Type of calibration or verification
Criteria
Minimum frequency 1
Linearity verification
Speed: < 0.05% FS for all measured increments
Load: < +/- 0.1% FS for all measured increments (or 10N?)
Speed: upon initial installation, within 370 days before testing, and after major maintenance.
Load: upon initial installation, within 370 days before testing, and after major maintenance. 2
Roll run-out & diameter
Run-out: < 0.25mm at all measured locations.
Diameter: within +/- 0.25mm of the specified nominal value at all measurement locations
Upon initial installation and after major maintenance 3
Time
Time error < +/ % 4
Speed measurement accuracy
Speed error < +/ kph
Upon initial installation, within 35 days before testing, and after major maintenance 5
Load transducer accuracy
Force error < 10N
Upon initial installation, within 370 days before testing, and after major maintenance 6
Response time
Response time < 100 ms 7
Base inertia
Base inertia error < +/- 0.5% for each measured base inertia, < +/- 0.2% relative to any mean value. 8
Parasitic loss verification
Measure losses and update calibration if any measured value differs from current curve by >2.5 N.
Upon initial installation, within 7 days before testing, and after major maintenance 9
Parasitic friction compensation evaluation
Friction compensation error < +/- 75 W 10
Acceleration & deceleration
Acceleration error < +/- 1% 11
Unloaded coastdown
Consider specifying SEE & r2 too?
Questions: maintain R83 Inertia Simulation Verification Test with +/- 2% tolerance as well?

2. Draft
Additional requirements for 4WD chassis dynamometers (to be demonstrated upon initial installation and after major maintenance)
Rolls speed synchronisation: front and rear rolls speed shall be synchronous to within 0.16 kph. This criteria should be applied to a 1s moving average of the speed of each roller when measured at a frequency of 20 Hz.
Distance: front and rear roll distances covered during a test shall be equivalent to within 0.02% of the distance travelled (test distance must be at least 150m).
Force distribution: both front and rear rolls shall be run in ‘road load simulation’ mode. The front/rear torque distribution shall be dictated by the vehicle, not by the dynamometer.