[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: 40CFR1065.510]

[Page 667-668]
 
                   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. 1065.510  Engine mapping procedures.

    (a) Torque map. Map your engine's torque while it is mounted on the 
dynamometer. Use the torque curve resulting from the mapping to convert 
the normalized torque values in the engine cycle to actual torque values 
for the test cycle. Make sure the speed ranges at least from the warm 
no-load idle speed to 105 percent of the maximum test speed. Because you 
determine the maximum test speed from the torque map, you may have to 
perform a preliminary torque map to determine the full mapping range. 
You may perform this preliminary torque map while the engine warms up. 
To map the engine, do the following things in sequence:
    (1) Warm up the engine so oil and water temperatures (on an absolute 
scale such as the Kelvin scale) vary by less than two percent for two 
minutes; or until the thermostat opens if the engine-coolant system 
includes a thermostat.
    (2) Operate the engine at the warm no-load idle speed.
    (3) Fully open the throttle.
    (4) While maintaining wide-open throttle and full-load, keep the 
engine at minimum speed for at least 15 seconds. Record the average 
torque during the last 5 seconds.
    (5) In increments of 10020 rpm, determine the 
maximum torque curve for the full speed range. Hold each test point for 
15 seconds and record the average torque over the last 5 seconds. You 
may use larger increments for engines with maximum test speed over 4000 
rpm, as long as you include at least 40 points and space them evenly.
    (6) Fit all data points recorded with a cubic spline, Akima, or 
other technique we approve in advance. The resultant curve must be 
accurate to within 1.0 ft-lbs. of all recorded 
engine torques.
    (b) Torque map with continual engine speed sweep. In place of 
paragraphs (a)(1) through (a)(4) of this section, you may do a continual 
sweep of engine speed. While operating at wide-open throttle, increase 
the engine speed at an average rate of 81 rpm/sec 
over the full speed range. You may use higher sweeping rates for 
naturally-aspirated engines, in accordance with good engineering 
judgment. Record speed and torque points at a rate of at least one point 
per second. Connect all points generated under this approach by linear 
interpolation.
    (c) Alternate mapping. You may use other mapping techniques if you 
believe those in paragraphs (a) and (b) of this section are unsafe or 
unrepresentative for any engine or engine family. These alternate 
techniques must satisfy the intent of the specified mapping procedures--
to determine the maximum available torque at all engine speeds that 
occur during the test cycles. Report deviations from this section's 
mapping techniques for reasons of safety or representativeness. In no 
case, however, may you use descending continual sweeps of engine speed 
for governed or turbocharged engines.
    (d) Replicate tests. You need not map an engine before every test, 
but you do need to remap the engine in any of the following situations:
    (1) Good engineering judgment determines that an unreasonable amount 
of time has passed since the last map.
    (2) The barometric pressure before the test begins has changed more 
than 25 mm Hg from the average barometric pressure observed during the 
map.
    (3) The engine has undergone physical changes or recalibration that 
might affect its performance.
    (e) Power map. Where applicable, generate a power map using the 
procedures this section specifies for torque maps. You may generate the 
power map directly or convert the torque map to a power map using engine 
speeds. The power map is also called a lug curve.
    (f) Cycles based only on torque/power at maximum test speed. If the 
applicable test cycle for your engine does not require map information 
for engine speeds other than the maximum test speed, you may make the 
following simplifications:
    (1) You need not perform the entire torque or power map, as long as 
you map the engines for speeds between 75 and 105 percent of the maximum 
test speed.

[[Page 668]]

    (2) You need not remap an engine according to paragraph (d) of this 
section. You need only verify the maximum torque or power at maximum 
test speed.