This section describes a procedure for mapping axle efficiency through a determination of axle power loss.
Where:
APloss = standard deviation of power loss values at a given torque-speed setting (see 40 CFR 1065.602(c) ).
N = number of repeat tests.
Pmax = maximum output torque setting from the test matrix.
Example:
APloss = 0.1650 kW
N = 3
Pmax
Confidence Interval = 0.0594%
P
Where:
Tin = mean input torque from paragraph (e)(4) of this section.
fnwheel = mean wheel angular speed from paragraph (e)(4) of this section in rad/s.
ka = drive axle ratio, expressed to at least the nearest 0.001.
Tout = mean output torque from paragraph (e)(4) of this section. Let Tout = 0 for all unloaded tests.
P
P
Tin,1
fnwheel,1
ka
Tout,1
Ploss,1
Ploss,1
Ploss,2
= 1603.9 W = 1.6039 kW
Ploss, corresponding to each test point for input into GEM. Express wheel angular speed in r/min to one decimal place; express output torque in N·m to two decimal places; express power loss in kW to four decimal places.
Ploss of untested axles for each speed and torque setpoint based on a linear relationship between your declared power loss and axle ratio as follows:
Ploss for untested configurations that are at or above the values you determined in paragraph (h)(3) of this section.
40 C.F.R. §1037.560