This section describes how to generate duty cycles that are specific to your engine, based on the normalized duty cycles in the standard-setting part. During an emission test, use a duty cycle that is specific to your engine to command engine speed, torque, and power, as applicable, using an engine dynamometer and an engine operator demand. Paragraphs (a) and (b) of this section describe how to "normalize" your engine's map to determine the maximum test speed or torque for your engine. The rest of this section describes how to use these values to "denormalize" the duty cycles in the standard-setting parts, which are all published on a normalized basis. Thus, the term "normalized" in paragraphs (a) and (b) of this section refers to different values than it does in the rest of the section.
Where:
i = an indexing variable that represents one recorded value of an engine map.
fnnormi = an engine speed normalized by dividing it by fnPmax.
Pnormi = an engine power normalized by dividing it by Pmax.
Pmax
(fn1 = 2360, P1 = 222.5, fnnorm1 = 1.002, Pnorm1 = 0.9675)
(fn2 = 2364, P2 = 226.8, fnnorm2 = 1.004, Pnorm2 = 0.9859)
(fn3 = 2369, P3 = 228.6, fnnorm3 = 1.006, Pnorm3 = 0.9940)
(fn4 = 2374, P4 = 218.7, fnnorm4 = 1.008, Pnorm4 = 0.9508)
Sum of squares = (1.0022 + 0.96752) = 1.94
Sum of squares = (1.0042 + 0.98592) = 1.98
Sum of squares = (1.0062 + 0.99402) = 2.00
Sum of squares = (1.0082 + 0.95082) = 1.92
Where:
fntest,alt = alternate maximum test speed
fnhi,idle = warm high-idle speed
fnidle = warm idle speed
% speedmax = maximum normalized speed from duty cycle
Example:
fnhi,idle = 2200 r/min
fnidle = 800 r/min
fntest,alt = 2133 r/min
Example:
% speed = 85% = 0.85
fntest = 2364 r/min
fnidle = 650 r/min
fnref = 0.85 [.] (2364-650) + 650
fnref = 2107 r/min
Example:
nlo
= 2385 r/min
'nrefA = 0.25 · (2385 - 1005) + 1005
'nrefB = 0.50 · (2385 - 1005) + 1005
'nrefC = 0.75 · (2385 - 1005) + 1005
'nrefD = 0.15 · (2385 - 1005) + 1005
'nrefA = 1350 r/min
'nrefB = 1695 r/min
'nrefC = 2040 r/min
'nrefD = 1212 r/min
40 C.F.R. §1065.610