[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: 40CFR1065.210]

[Page 702-705]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 1065_ENGINE-TESTING PROCEDURES--Table of Contents
 
                    Subpart C_Measurement Instruments
 
Sec.  1065.210  Work input and output sensors.

    (a) Application. Use instruments as specified in this section to 
measure work inputs and outputs during engine operation. We recommend 
that you use sensors, transducers, and meters that meet the 
specifications in Table 1 of Sec.  1065.205. Note that your overall 
systems for measuring work inputs and outputs must meet the linearity 
verifications in Sec.  1065.307. We recommend that you measure work 
inputs and outputs where they cross the system boundary as shown in 
Figure 1 of this section. The system boundary is different for air-
cooled engines than for liquid-cooled engines. If you choose to measure 
work before or after a work conversion, relative to the system boundary, 
use good engineering judgment to estimate any work-conversion

[[Page 703]]

losses in a way that avoids overestimation of total work. For example, 
if it is impractical to instrument the shaft of an exhaust turbine 
generating electrical work, you may decide to measure its converted 
electrical work. In this case, divide the electrical work by an accurate 
value of electrical generator efficiency ([eta]<1), or assume an 
efficiency of 1 ([eta]=1), which would over-estimate brake-specific 
emissions. Do not underestimate the generator's efficiency because this 
would result in an under-estimation of brake-specific emissions. In all 
cases, ensure that you are able to accurately demonstrate compliance 
with the applicable standards.

[[Page 704]]

[GRAPHIC] [TIFF OMITTED] TR13JY05.015

    (b) Shaft work. Use speed and torque transducer outputs to calculate 
total work according to Sec.  1065.650.
    (1) Speed. Use a magnetic or optical shaft-position detector with a 
resolution of at least 60 counts per revolution, in combination with a 
frequency

[[Page 705]]

counter that rejects common-mode noise.
    (2) Torque. You may use a variety of methods to determine engine 
torque. As needed, and based on good engineering judgment, compensate 
for torque induced by the inertia of accelerating and decelerating 
components connected to the flywheel, such as the drive shaft and 
dynamometer rotor. Use any of the following methods to determine engine 
torque:
    (i) Measure torque by mounting a strain gage or similar instrument 
in-line between the engine and dynamometer.
    (ii) Measure torque by mounting a strain gage or similar instrument 
on a lever arm connected to the dynamometer housing.
    (iii) Calculate torque from internal dynamometer signals, such as 
armature current, as long as you calibrate this measurement as described 
in Sec.  1065.310.
    (c) Electrical work. Use a watt-hour meter output to calculate total 
work according to Sec.  1065.650. Use a watt-hour meter that outputs 
active power (kW). Watt-hour meters typically combine a Wheatstone 
bridge voltmeter and a Hall-effect clamp-on ammeter into a single 
microprocessor-based instrument that analyzes and outputs several 
parameters, such as alternating or direct current voltage (V), current 
(A), power factor (pf), apparent power (VA), reactive power (VAR), and 
active power (W).
    (d) Pump, compressor or turbine work. Use pressure transducer and 
flow-meter outputs to calculate total work according to Sec.  1065.650. 
For flow meters, see Sec.  1065.220 through Sec.  1065.248.