[Code of Federal Regulations]
[Title 40, Volume 30]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1065.515]

[Page 668-669]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1065_TEST PROCEDURES AND EQUIPMENT--Table of Contents
 
                   Subpart F_Running an Emission Test
 
Sec. 1065.515  Test cycle generation.

    (a) Denormalizing test cycles. The standard-setting parts establish 
the applicable test cycles consisting of second-by-second specifications 
for normalized torque and speed for transient cycles, or modal 
specifications for normalized torque and speed (or power and speed) for 
steady-state cycles. You must denormalize these values to get actual 
torque and speed for your engine.
    (1) Torque is normalized to a maximum-torque value. Check the 
standard-setting part to see if it is normalized based on the maximum 
torque at the given speed or based on the maximum torque for all speeds. 
To denormalize the torque values in the cycle, use the engine's maximum-
torque point or its torque map (Sec. 1065.510 describes how to generate 
the torque map).
    (2) Power is normalized to a maximum-power value. Check the 
standard-setting part to see if it is normalized based on the maximum 
power at the given speed or based on the maximum power for all speeds. 
To denormalize the power values in the cycle, use the engine's maximum-
power point or its power map (Sec. 1065.510 describes how to generate 
the power map).
    (3) To denormalize speed, use the following equation:

Actual engine speed = (0.01) x (%engine speed) x (Maximum test speed--
    warm idle speed) + warm idle speed

    (4) Paragraph (d) of this section describes how to calculate maximum 
test speed.
    (b) Example of denormalizing a test points. For an engine with 
maximum test speed of 3800 rpm and warm idle speed of 600 rpm, 
denormalize the following test point: percent engine speed = 43, percent 
torque = 82.
    (1) Calculate actual engine speed. The following equation applies 
for this example:

Actual engine speed = (0.01) x (43) x (3800-600) + 600 = 1976 rpm.

    (2) Determine actual torque. Determine the maximum observed torque 
at 1976 rpm from the maximum torque curve. Then multiply this value (for 
example, 358 ft-lbs.) by 0.82. The resulting actual torque is 294 ft-
lbs.
    (c) Cold-start enhancement devices. If an engine has a properly 
operating automatic enhancement device for cold starts, let it override 
the zero-percent speed specified in the test cycles.
    (d) Maximum test speed. For constant-speed engines, maximum test 
speed is the same as the engine's maximum operating speed in use. 
Maximum test speed for variable-speed engines occurs on the lug curve at 
the point farthest from the origin on a plot of power vs. speed. To find 
this speed, follow three main steps:
    (1) Generate the lug curve. Before testing an engine for emissions, 
generate data points for maximum measured brake power with varying 
engine speed (see Sec. 1065.510). These data points form the lug curve.
    (2) Normalize the lug curve. To normalize the lug curve, do three 
things:
    (i) Identify the point (power and speed) on the lug curve where 
maximum power occurs.
    (ii) Normalize the power values of the lug curve--divide them by the 
maximum power and multiply the resulting values by 100.
    (iii) Normalize the engine speed values of the lug curve--divide 
them by the speed at which maximum power occurs and multiply the 
resulting values by 100.
    (3) Determine maximum test speed. Calculate the maximum test speed 
from the following speed-factor analysis:
    (i) For a given power-speed point, the speed factor is the 
normalized distance to the power-speed point from the zero-power, zero-
speed point. Compute the speed factor's value: 
[GRAPHIC] [TIFF OMITTED] TR08NO02.015

    (ii) Determine the maximum value of speed factors for all the power-
speed data points on the lug curve. Maximum test speed is the speed at 
which the speed factor's maximum value occurs. Note that this maximum 
test speed is

[[Page 669]]

the 100-percent speed point for normalized transient duty cycles.
    (e) Intermediate test speed. Determine intermediate test speed with 
the following provisions:
    (1) If peak torque speed is 60 to 75 percent of the maximum test 
speed, the intermediate speed point is at that same speed.
    (2) If peak torque speed is less than 60 percent of the maximum test 
speed, the intermediate speed point is at 60 percent of maximum test 
speed.
    (3) If peak torque speed is greater than 75 percent of the maximum 
test speed, the intermediate speed point is at 75 percent of maximum 
test speed.