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$ 85.79 Information to be recorded on (d) Instrument Operator. charts.

(e) Driver. The following information shall be re- (f) Vehicle: Make-Vehicle Identifcorded with respect to each test:

cation Number-Year-Transmission (a) Test Number.

type-Odometer reading-Engine dis(b) System or device tested.

placement-Carburetor barrels-Idle (c) Date and time of day.

rpm-Position of idle mixture screws.

(g) Analyzer Tuning-Gain-Detector number.

(h) Identify zero traces, steadystate traces, calibration traces, and start and finish of each test.

(i) Record sample cell pressure.

(j) Ambient temperature (i.e. air in front of radiator).

$ 85.80 Calibration and instrument

checks.

(a) Calibrate following assembly, and repeat every 30 days thereafter. Use the same flow rate as when sampling exhaust. Adjust to the same pressure setting on the manometer as observed during sampling. Proceed as follows:

(1) Clean cells and tune analyzers.

(2) Zero on nitrogen. Check each cylinder of N, for contamination with hydrocarbons. Set the instrument gain to give the desired range. Normal operating ranges are as follows:

Low Range Hydro- 0–1,750 ppm hexane.

carbon Analyzer. High Range Hydro- 0-10,000 ppm. hexcarbon Analyzer.

ane. CO Analyzer---- 0-12% CO. CO, Analyzer... 0-16% CO,

(3) Calibrate with the following gases. The concentrations given indicate nominal concentrations and actual concentrations should be known to within 22% of true value. Dry N. is used as the diluent.

Minimum use temperature of the cylinders should be 70° F.

(4) Compare values with previous curves. Any significant change reflects some problem in the system. Locate and correct problem, and recalibrate. Use best judgment in selecting curve for data reduction.

(5) Check response of hydrocarbon analyzer to 100% CO2. If response is greater than 0.5% full scale, refill slter cells with 100% CO, and recheck. Note any remaining response on chart.

If response still exceeds 0.5%, replace detector.

(6) Check response of hydrocarbon analyzers to air saturated with water at ambient temperature. Record ambient temperature. If the low range instrument response exceeds 5% of full scale with saturated air at 75° F., replace the detector. If the high range response exceeds 0.5% of full scale, check detector on low range instrument, then reject if response exceeds 5% of full scale at 75° F.

(b) Daily instrument check: Allow & minimum of 2 hours warmup for infrared analyzers. (Power is normally left on continuously; but, when instruments are not in use, chopper motor is turned off.) The following should be done before each series of tests:

(1) Zero on clean nitrogen introduced at analyzer inlet. Obtain a stable zero on the amplifier meter and recorder. Recheck after test.

(2) Introduce normalizing gas and set gain to match calibration curve.

In order to avoid a correction for sample cell pressure, normalize and calibrate at the same cell pressure determined in $ 85.78 (e) (4). Normalizing or span gases: See $ 85.80(a) (3) for allowable variation. Low Range Hydro- 1,500–1,700 ppm hexcarbon Analyzer.

propane equivalent for the

instrument. High Range Hydro- 5,000 ppm hexane or carbon Analyzer. propane equivalent

for the instrument. CO Analyzer-

10% CO in N. Co, Analyzer-- 12 to 16% CO, in N,

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100 ppm hexane... 1000 ppm hexane

(1100 p.s.i.g.

max. pressure) : 200 ppm hexane.. 2000 ppm hexane

(500 p.s.i.g.) 1 600 ppm hexane.. 5000 ppm hexane

(300 p.s.i.g.): 750 ppm hexane.. 7500 ppm hexane

ane

or

10

16

(200 p.s.i.g.) 1 1000 ppm hexane.. 9000-10,000 ppm

hexane (150

p.s.i.g.) i 1750 ppm hexane..

1 The above are the maximum suggested pressures to prevent cylinder wall adsorption errors, etc.

of gain has shifted significantly, check tuning. If necessary then check calibration. Recheck after test. Show actual concentrations on chart.

(3) Check nitrogen zero, repeat (1) and (2) if required.

(4) Check flow rates and pressure as described in $ 85.78(e) (3) and (4). $ 85.81 Cold start test run.

(a) The car and device are allowed to stand long enough to reach ambient temperature (at least 12 hours). The vehicle is to be stored prior to the test in such a manner that precipitation (e.g., rain or dew) does not occur on the vehicle and the minimum ambient temperature in the vicinity of the engine during the soak period is 60° F. During the run the ambient temperature should be between 68° and 86°F.

(b) The following steps shall then be taken for each test. (Special procedures may be required for certain cars: for example, those equipped with dual exhaust systems. These problems must be handled on an individual basis, and a procedure agreed to by the Surgeon General established.)

(1) Place car on dynamometer without starting engine.

(2) Clean condensate traps and change filter thimbles.

(3) Purge entire sampling system by allowing air to enter at probe.

(4) Purge the instruments with nitrogen. Turn on chart drive and adjust the zero. Check span.

(5) Stop the nitrogen purge and switch the analyzers to the exhaust sampling train. Adjust each flow rate. Note and record the sample system pressures on chart.

(6) Insert the sampling line at least 2 feet into the tailpipe. If this is not possible, a tailpipe extension should be used. Break connection to train.

(7) With car hood up, start the cooling fan.

(8) Start the car. After the engine has run 20 seconds, connect sample line to train.

(9) Run 7 seven-mode cycles.

(10) Change glass wool in coarse filter during idle following cycle 2.

(11) Record manifold vacuum during 50 m.p.h. cruise.

(12) Record on the dynamometer data sheet the engine idle r.p.m.: In drive range for automatics, in neutral for manuals.

(13) Remove probe from exhaust and determine air response (hangup). As a guide, the hydrocarbon concentration should drop to 5% of scale in 10 seconds and 2-4% of scale in 2-3 minutes. If it does not, the test is questionable.

(14) Record nitrogen zero, and check span. If zero and span drift is in excess of 3% of the span concentration during the run, the results are questionable. $ 85.82

Chart reading. The recorder response for measuring exhaust gas concentrations will always lag the engine's operation because of a variable exhaust system delay and a fixed sample system delay. Therefore, the concentrations for each mode will not be located on the charts at a point corresponding to the exact time of the mode. For each warmup cycle to be evaluated, proceed as follows:

(a) Determine whether the cycle was driven in accordance with the specified cycle timing by observing either chart pips, speed trace, manifold vacuum trace, or concentration traces. Deviation by more than 2 seconds from the specified time for each mode will make the data of questionable value.

(b) Time correlate the hydrocarbon, carbon monoxide, and carbon dioxide charts. Use all clues available to determine the location on the chart of concentrations corresponding to each mode. Use judgment in recognizing and compensating for trace abnormalities.

(c) Locate on each chart the last three (3) seconds before HC, CO and CO, concentration changes indicate the beginning of the 0-25 acceleration. From this last three (3) second period determine the integrated or time average concentration for the idle concentration.

(d) Mark off the 11.5 seconds following the point located in step c. Integrate or time average the concentrations in this interval for the 0-25 acceleration concentrations.

(e) Locate the last three (3) seconds before concentration changes indicate the beginning of the 30–15 deceleration. Integrate or time average the concentrations for the cruise 30 values.

(f) Locate chart scale reading (ordinate) where peak width equals eleven (11) seconds for 30–15 deceleration. Integrate or time average the concentrations between the intersections of this scale reading with the curve for the 3015 deceleration values.

(g) Locate the last three (3) seconds before concentration changes associated with the beginning of the 15-30 acceleration and integrate or time average the concentrations for the cruise 15 value.

(h) From the initiation of the 15-30 (50) acceleration located in step g, measure 12.5 seconds forward in time and evaluate the integrated or time average concentration for the 15-30 value.

(i) Locate chart scale reading where peak width equals 25 seconds for the 5020 deceleration mode. Integrate or time average the concentrations between the intersections of this scale reading with the curve for the 50–20 deceleration values. The “time average concentrations” equal the sum of the concentration values for each second of time divided by the number of seconds. The concentration at any second is determined by:

(1) Reading recorder deflection.

(2) Subtracting water, plus CO, response.

(3) Referring to the calibration curve to determine concentration. (A table corresponding to the calibration curve is a useful aid.) Integration of the area under the curves has been found to be an acceptable approximation of the more rigorous "time average concentration" method.

(j) Record data for the first four warmup cycles and the sixth and seyenth hot cycles.

NOTE: The time correlation of the various chart traces is emphasized. The peak spanning method of locating the deceleration modes is appropriate only for the hydrocarbon traces. Corresponding co and co, values should be located by time correlation.

§ 85.83 Calculations.

The final reported tests results are derived through the following steps:

(a) Exhaust gas concentrations shall be adjusted to a dry exhaust volume containing 15 percent by volume of carbon dioxide plus carbon monoxide.

(b) Determine composite hydrocarbon and carbon monoxide concentrations for the first four seven-mode warmup cycles.

(c) Determine composite hydrocarbon and carbon monoxide concentrations for the sixth and seventh (hot) cycles.

(d) Combine (b) and (c) according to the formula 0.35(b) and 0.65(c).

Example: The following example Wlustrates the calculation of reported values from raw data. The raw concentrations used in the warmup portion of the example represent the average mode concentrations for the first four cycles.

Since hydrocarbons, carbon monoxide, and carbon dioxide are all measured with the same moisture content, no moisture correction 18 required to convert the results to s dry basis. The correction factor

15

co+co, is applied to the measured concentrations of hydrocarbons and carbon monoxide for each load mode and the idle mode. For the deceleration modes the measured concentra. tions are multiplied by

15

6HC+CO+CO, (HC expressed as % hexane). This modii. cation is necessary to compensate for the large percentage of carbon atoms which remain in organic form during these modes. (Special treatment will be necessary for cases involving fuel shutoff during deceleration in accordance with a substantially equivalent procedure agreed to by the Surgeon General.)

By a similar procedure the hot portion of the test yields composite values of 680 and 2.21. The reported overall composite values are:

0.35 (697) +0.85 (680) = 686 ppm HC. 0.35 (2.27) +0.65 (2.21)=2.24% CO.

1 The average concentration for each mode for the first four warmup cycles is determined, and then the CO plus CO, correction factor is applied to this average for each mode.

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$ 85.84 Test vehicles.

(b) Durability data vehicles. The dur(a) Emission data vehicles. (1) Four ability data vehicles shall comprise a vehicles of each engine displacement will minimum of 4 and a maximum of 10, the be run for emission data. Where an number being determined by selection engine displacement projected sales vol- of those combinations of engine displaceume represents less than one half of one ment and transmission options (autopercent of the last full model year's total matic and manual) which represent at United States sales of all vehicles subject

least 70 percent of the manufacturer's to this part, then a total of two vehicles

total sales in the United States during would be required for that displacement.

the latest full model year for which sales Each manufacturer, however, must accumulate data on a minimum of four

statistics are available, selected in order vehicles to qualify for certification.

of sales volume: Provided, however, That (2) Vehicles shall be selected so as to

when such manufacturer's total latest be equipped as nearly as possible with full model year sales in the United States transmission and carburetors in propor- represent less than 10 percent of all dotion to the manufacturer's percentages mestic sales of vehicles subject to this thereof sold in the United States during part, the number of durability data velatest full model year for which sales hicles will be determined by the numstatistics are available.

ber of engine displacement and trans(3) An engine and transmission com

mission options comprising at least 50 bination need not be tested in more than

percent of domestic sales by the manone car model except that where the weight, power train, or other character

ufacturer during such model year, but in istics of any car model may reasonably

no event shall there be less than 4 vebe expected to increase emissions, the hicles unless a lesser number is agreed to engine and transmission combination by the Surgeon General as meeting the shall also be tested in such model. objectives of this procedure.

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