Pennsylvania Code › Title 67 - TRANSPORTATION › Part I - Department of Transportation › Subpart A - Vehicle Code Provisions › Article VII - Vehicle Characteristics › Chapter 169 - DIESEL SMOKE MEASUREMENT PROCEDURE › Section 169.7 - Equipment and instrumentation

Current through Register Vol. 54, No. 28, July 13, 2024
The following equipment and instruments shall be used for
						smoke emissions and service simulation tests:
(1) An engine dynamometer with adequate
					 characteristics to perform the tests required by the provisions of §
											169.5 (relating to smoke test
					 cycle).
(2) Provide an exhaust
					 system of proper diameter and suitable length for the engine being tested, with
					 provisions for mounting the smoke opacimeter. Test data show that a range of
					 length 4 to 20 feet (1.2 to 6.1 meters) does not change the meter reading. In
					 the case of short exhaust systems, the opacimeter may be affected by the high
					 temperature. The system shall be capable of being adjusted to meet the exhaust
					 back pressure required to comply with the provisions of §
											169.4 (relating to smoke emission
					 test). Install a 2 foot (610 millimeters) section of smooth circular pipe, free
					 of elbows and bends, prior to the smoke opacimeter location. If an opacimeter
					 which mounts at the end of the exhaust system is used, the optical unit of the
					 opacimeter shall be mounted radially to the exhaust pipe so that the
					 measurement will be made at right angles to the axis of the exhaust plume. The
					 opacimeter shall be located at the termination of the exhaust stack with the
					 light beam of the opacimeter just clearing the stack termination point. The
					 full flow of the exhaust stream shall be centered between the source and
					 detector apertures, or windows and lenses, and on the axis of the light beam.
					 If a muffler is needed, a conventional automotive muffler of a size and type
					 commonly used with the engine may be installed in this system.
(3) Mount a full-flow, light-extinction,
					 smoke opacimeter in or on the exhaust system at the location specified in
					 paragraph (2). When dual exhaust systems are used, both systems shall be
					 equipped with a smoke opacimeter measuring an exhaust stream of (127
					 millimeters) diameter or larger.
(4) Smoke opacity and engine speed shall be
					 monitored continuously, using a strip chart recorder or equivalent, with a
					 minimum speed range of .5-15 inches per minute (13-381 millimeters per minute),
					 and a maximum full-scale response time for smoke opacity of .5 second.
					 (Response time for 95% to 100% of full-scale within .5 second). The reading
					 shall stabilize at 100% within 1 second. An automatic marker indicating 1
					 second intervals to verify chart speed is desirable.
(5) The various components, opacimeter,
					 electronic filters and recorder, should comprise a system capable of data
					 output within the following limits:
(i) The
					 smoke opacity trace shall be linear when calibrated to read from zero to 100%
					 (full-scale). The trace should have a resolution within 1% of full-scale
					 reading.
(ii) The engine speed
					 trace shall be linear when calibrated to read from the low idle speed to rated
					 engine speed. The trace should have a resolution within 1% of rated engine
					 speed.
(iii) The chart speed used
					 to record smoke opacity shall provide a time resolution of at least .25
					 second.