[Code of Federal Regulations]
[Title 40, Volume 31]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1065.125]

[Page 688]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents
 
                   Subpart B_Equipment Specifications
 
Sec.  1065.125  Engine intake air.

    (a) Use the intake-air system installed on the engine or one that 
represents a typical in-use configuration. This includes the charge-air 
cooling and exhaust gas recirculation systems.
    (b) Measure temperature, humidity, and atmospheric pressure near the 
entrance to the engine's air filter, or at the inlet to the air intake 
system for engines that have no air filter. You may use a shared 
atmospheric pressure meter as long as your equipment for handling intake 
air maintains ambient pressure where you test the engine within 1 kPa of the shared atmospheric pressure. You may use a 
shared humidity measurement for intake air as long as your equipment for 
handling intake air maintains dewpoint where you test the engine to 
within 0.5 [deg]C of the shared humidity 
measurement.
    (c) Use an air-intake restriction that represents production 
engines. Make sure the intake-air restriction is between the 
manufacturer's specified maximum for a clean filter and the 
manufacturer's specified maximum allowed. Measure the static 
differential pressure of the restriction at the location and at the 
speed and torque set points specified by the manufacturer. If the 
manufacturer does not specify a location, measure this pressure upstream 
any turbocharger or exhaust gas recirculation system connection to the 
intake air system. If the manufacturer does not specify speed and torque 
points, measure this pressure while the engine outputs maximum power. As 
the manufacturer, you are liable for emission compliance for all values 
up to the maximum restriction you specify for a particular engine.
    (d) This paragraph (d) includes provisions for simulating charge-air 
cooling in the laboratory. This approach is described in paragraph 
(d)(1) of this section. Limits on using this approach are described in 
paragraphs (d)(2) and (3) of this section.
    (1) Use a charge-air cooling system with a total intake-air capacity 
that represents production engines' in-use installation. Maintain 
coolant conditions as follows:
    (i) Maintain a coolant temperature of at least 20 [deg]C at the 
inlet to the charge-air cooler throughout testing.
    (ii) At maximum engine power, set the coolant flow rate to achieve 
an air temperature within 5 [deg]C of the value 
specified by the manufacturer at the charge-air cooler outlet. Measure 
the air-outlet temperature at the location specified by the 
manufacturer. Use this coolant flow rate set point throughout testing.
    (2) Using a constant flow rate as described in paragraph (d)(1)(ii) 
of this section may result in unrepresentative overcooling of the intake 
air. If this causes any regulated emission to decrease, then you may 
still use this approach, but only if the effect on emissions is smaller 
than the degree to which you meet the applicable emission standards. If 
the effect on emissions is larger than the degree to which you meet the 
applicable emission standards, you must use a variable flow rate that 
controls intake-air temperatures to be representative of in-use 
operation.
    (3) This approach does not apply for field testing. You may not 
correct measured emission levels from field testing to account for any 
differences caused by the simulated cooling in the laboratory.