Where:
FR = total road-load force to be applied at the surface of the roll. The total force is the sum of the individual tractive forces applied at each roll surface.
i = a counter to indicate a point in time over the driving schedule. For a dynamometer operating at 10-Hz intervals over a 600-second driving schedule, the maximum value of i should be 6,000.
A = a vehicle-specific constant value representing the vehicle's frictional load in lbf or newtons. See subpart D of this part.
Gi = instantaneous road grade, in percent. If your duty cycle is not subject to road grade, set this value to 0.
B = a vehicle-specific coefficient representing load from drag and rolling resistance, which are a function of vehicle speed, in lbf/(mi/hr) or N·s/m. See subpart D of this part.
v = instantaneous linear speed at the roll surfaces as measured by the dynamometer, in mi/hr or m/s. Let vi-1 = 0 for i = 0.
C = a vehicle-specific coefficient representing aerodynamic effects, which are a function of vehicle speed squared, in lbf/(mi/hr)2 or N·s2/m2. See subpart D of this part.
Me = the vehicle's effective mass in lbm or kg, including the effect of rotating axles as specified in § 1066.310(b)(7) .
t = elapsed time in the driving schedule as measured by the dynamometer, in seconds. Let ti-1 = 0 for i = 0.
M = the measured vehicle mass, in lbm or kg.
ag = acceleration of Earth's gravity = 9.80665 m/s2.
40 C.F.R. §1066.210