This section describes a procedure for mapping axle efficiency through a determination of axle power loss.
Where:
[SIGMA]Ploss = 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:
[SIGMA]Ploss = 0.1650 kW
N = 3
= 314.2000 kW
Confidence Interval = 0.0594%
Ploss, at each test point as follows:
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.
Ploss as the mean power loss from all measurements at a given test point.
Ploss:
= 845.10 N·m
= 100.0 r/min = 10.472 rad/s
= 3.731
= 3000.00 N·m
= 845.10 · 10.472 · 3.731 - 3000.00 · 10.472
= 1602.9 W = 1.6029 kW
= 1601.9 W = 1.6019 kW
= 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