[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.314-79]

[Page 598]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND 
ENGINES--Table of Contents
 
Subpart D_Emission Regulations for New Gasoline-Fueled and Diesel-Fueled 
           Heavy-Duty Engines; Gaseous Exhaust Test Procedures
 
Sec. 86.314-79  Fuel flow measurement specifications.

    (a) The fuel flow rate measurement instrument must have a minimum 
accuracy of 1 percent of full-scale flow rate for 
each measurement range used. An exception for Diesel engines is allowed 
at the idle and 2-percent power points. For these modes, the minimum 
accuracy is 2 percent of full-scale flow rate for 
each measurement range used. The controlling parameters are the elapsed 
time measurement of the event and the weight or volume meas urement. 
Restrictions on these parameters are:
    (1) The error in the elapsed time measurement of the event must not 
be greater than 1 percent of the absolute event time. This includes 
errors in starting and stopping the clock as well as the period of the 
clock.
    (2) For Diesel engines only, if the mass of fuel consumed is 
measured by discrete weights, then the error in the actual weight of the 
fuel consumed must not be greater than 1 percent 
of the measuring weight. An exception for Diesel engines is allowed at 
the idle and 2-percent power points. For these modes the error in the 
actual weight of the fuel consumed must not be greater than 2 percent of the measuring weight.
    (3) If the mass of fuel consumed is measured electronically (load 
cell, load beam, etc.), the error in the actual weight of fuel consumed 
must not be greater than 1 percent of the full-
scale value of the electronic device.
    (4) If the mass of fuel consumed is measured by volume flow and 
density, the error in the actual volume consumed must not be greater 
than 1 percent of the full-scale value of the 
volume measuring device.
    (b) For the devices that have varying mass scales (electronic 
weight, volume, density, etc.), measurements may not be used for 
calculations if the measurement is less than 20 percent of full scale.
    (c) Option. Complete flow-rate measurement systems may be used below 
20 percent of full-scale measurement as long as the combination of mass 
and time measurements indicate a flow rate that has an error of less 
than 5 percent of the absolute flow rate.