NAC445B.587. Testing of certain motor vehicles powered by diesel engines: Equipment for measurement of smoke opacity.

     1. Equipment for the measurement of smoke opacity from:

     (a) Light-duty motor vehicles that are powered by diesel engines; and

     (b) Heavy-duty motor vehicles that are powered by diesel engines and have a manufacturer’s gross vehicle weight rating which does not exceed 14,000 pounds,

Ê must include a dynamometer and a smoke opacity meter.

     2. The dynamometer must have:

     (a) The capacity to absorb a minimum of 100 horsepower.

     (b) A mechanism for controlling the load that is capable of:

          (1) Infinitely variable settings throughout the load and speed range from no-load to full-load;

          (2) Being set at a load or speed and, until deactivated, maintaining a preset setting without additional input from the load controller; and

          (3) Being operated in the following function modes:

               (I) Constant speed;

               (II) Constant torque;

               (III) Constant horsepower; and

               (IV) Manual absorber.

     (c) Computer controls which include, without limitation:

          (1) A model 286 12-megahertz central processing unit;

          (2) A 256 kilobyte video graphic array color card;

          (3) A 1.44 megabyte floppy drive;

          (4) Five hundred and twelve kilobytes of random access memory;

          (5) Parallel printer interface; and

          (6) Digital and analog data acquisition interface.

     (d) A minimum roller diameter of 8.5 inches.

     (e) One hundred and fifteen volt AC single phase 60 Hz power.

     (f) A weight limit of 6,000 pounds per axle.

     (g) A provision for checking the accuracy of the calibration of the dynamometer in the field, including, without limitation, an electrical output signal, interface and attendant instrumentation. Equipment, tools and procedures recommended or specified by the manufacturer for the calibration and adjustment of the dynamometer must be available.

     3. The smoke opacity meter must have:

     (a) Calibration accuracy within 1 percent.

     (b) Linearity within 1 percent, from 0 to 60 percent opacity.

     (c) Drift within 1 percent of the temperature range specified by the manufacturer.

     (d) A response time of less than 2 seconds from 0 to 90 percent of scale.

     (e) A warm-up time of not more than 10 minutes.

     (f) An operating temperature range from 32 to 120 degrees Fahrenheit.

     (g) One hundred and fifteen volts AC input, if operated from alternating current.

     (h) Batteries which are replaceable or rechargeable, and which allow for the operation of the smoke opacity meter without AC input.

     (i) A RS232C standardized serial interface.

     (j) The ability to measure exhaust opacity continuously.

     (Added to NAC by Dep’t of Motor Veh. & Pub. Safety, eff. 11-10-92; A by R079-98, 9-25-98; A by Environmental Comm’n by R130-09, 1-28-2010)