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(c) Meaning of symbols—Continued

HCmass=Hydrocarbon emissions, in grams per vehicle mile. Densityhc=Density of hydrocarbons in the exhaust gas, assuming an average carbon

to hydrogen ratio of 1:1.85, in grams per cubic foot at 68° F. and

760 mm. Hg pressure (16.33 gm./cu. ft.). HCconc=Hydrocarbon concentration of the exhaust mixture sample minus hydro

carbon concentration of the dilution air sample, in p.p.m. carbon

equivalent (p.p.m. C.), i.e., equivalent propane X3.
COmass=Carbon monoxide emissions, in grams per vehicle mile.
Densityco=Density of carbon monoxide in grams per cubic foot at 68° F. and 760 mm.

Hg pressure (32.97 gm./cu. ft.).
COconc=Carbon monoxide concentration of the dilute exhaust sample minus the

carbon monoxide concentration of the dilution air sample, in volume

percent. (d) Example calculation of mass emission values: Assume Vo=0.265 cu. ft. per revolution; N=20,250; Pp=730 mm. Hg; Tp=550° R; HCconc=160 p.p.m. C; and Coconc=0.09%. Vmix=(0.09263) (0.265) (20,250) (730/550) =659.8 cu. ft. per mile. (1) For a 1972 light-duty vehicle.

160 HCmass=659.8 X 16.33 X , (2) For a 1972 off-road utility vehicle.

COmass=659.8 x 32.97 x 0.09

1,000,000 =1.72

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$ 1201.88 Calculations (fuel evaporative (3) Engines identical in all the reemissions).

spects listed in subparagraph (2) of this The net weights of the individual col paragraph may be further divided into lection traps employed in § 1201.74 shall

different engine families if the Secretary be added together to determine compli

determines that they may be expected to ance with the fuel evaporative emission

have different emission characteristics. standard.

This determination will be based upon a

consideration of the following features $ 1201.89 Test vehicles.

of each engine: (a) (1) The vehicles covered by the

(i) The bore and stroke. application for certification will be di (ii) The surface to volume ratio of the vided into groupings of vehicles whose

of vehicles whose nominally dimensioned cylinder at the engines are expected to have similar

top dead center position. emission characteristics. Each group of

(iii) The intake manifold induction engines with similar emission character

port size and configuration. istics shall be defined as a separate engine

(iv) The exhaust manifold port size family.

and configuration. (2) To be classed in the same engine

(v) The intake and exhaust valve family, engines must be identical in all

sizes. the following respects:

(vi) The fuel system. (i) The cylinder bore center to center

(vii) The camshaft timing and ignidimensions.

tion timing characteristics. (ii) The dimension from the centerline

(4) Where engines are of a type which of the crankshaft to the centerline of

cannot be divided into engine families the camshaft.

based upon the criteria listed in subpara(iii) The dimension from the center

graph (2) and (3) of this paragraph, the line of the crankshaft to the top of the

Secretary will establish families for those cylinder block head face.

engines based upon the features most re(iv) The cylinder block configuration

lated to their emission Characteristics.

(b) Emission data vehicles: (air-cooled or water-cooled; L-6, 90° V-8,

(1) Vehicles will be chosen to be etc.).

operated and tested for emission data (v) The location of intake and exhaust

based upon the engine family groupings. valves and the valve sizes (within a 18

Within each engine family, the requireinch range on the valve head diameter).

ments of this paragraph must be met. (vi) The method of air aspiration.

(2) Vehicles of each engine family (vii) The combustion cycle.

will be divided into engine displacement

chaust emission control system fleet shall contain at least two vehicles 'aporative emission control system com with each combination. The additional nations. A projected sales volume will vehicle will be selected in the same mane established for each combination for ner as vehicles selected under subte model year for which certification is paragraph (1) of this paragraph. pught. One vehicle of each combination (3) A manufacturer may elect to opill be selected in order of decreasing erate and test additional vehicles to rojected sales volume until 70 percent represent any engine-system combinaE the projected sales of a manu tion. The additional vehicles must be of acturer's total production of vehicles of the same engine displacement, transmishat engine family is represented, or sion type, fuel system and inertia weight ntil a maximum of four vehicles is class as the vehicle selected for that elected. If any single combination rep engine-system combination in accordesents over 70 percent, then two vehicles ance with the provisions of subpargraph f that combination will be selected. The (1) of this paragraph. Notice of an inehicle selected for each combination tent to operate and test additional verill be specified by the Secretary as to hicles shall be given to the Secretary ransmission type, fuel system and in not later than 30 days following notificartia weight class.

tion of the test fleet selection. (3) The Secretary may select a maxi (d) For purposes of testing under ium of four additional vehicles within $ 1201.91 (g), the Secretary may require ach engine family based upon features additional emission data vehicles and ndicating that they may have the high- durability data vehicles identical in all st emission levels of the vehicles in that material respects to vehicles selected in ngine family. In selecting these vehicles, accordance with paragraphs (b) and (c) he Secretary will consider such features of this section: Provided, That the nums the emission control system combina ber of vehicles selected shall not increase ion, induction system characteristics, the size of either the emission data fleet gnition system characteristics, fuel sys or the durability data fleet by more than em, rated horsepower, rated torque, 20 percent or one vehicle, whichever is ompression ratio, inertia weight class, greater. ransmission options and axle ratios.

(e) Any manufacturer whose projected (4) If the vehicles selected in accord sales of new motor vehicles subject to ince with subparagraphs (2) and (3) of this subpart for the model year for his paragraph do not represent each which certification is sought is less than angine-system combination, then one 2,000 vehicles may request a reduction vehicle of each engine-system combina in the number of test vehicles determined Lion not represented will be selected by in accordance with the foregoing provithe Secretary. The vehicle selected shall sions of this section. The Secretary may be of the engine displacement with the agree to such lesser number as he deterlargest projected sales volume of vehicles mines would meet the objectives of this with the control system combination in procedure. the engine family and will be designated (f) In lieu of testing an emission data by the Secretary as to transmission type, or durability data vehicle selected under fuel system and inertia weight class.

paragraph (b) or (c) of this section, and (c) Durability data vehicles:

submitting data therefor, a manufacturer (1) A durability data vehicle will be may, with the prior written approval of selected by the Secretary to represent the Secretary, submit data on a similar each engine-system combination. The vehicle for which certification has prevehicle selected shall be of the engine viously been obtained. displacement with the largest projected (g) (1) Where it is expected that sales volume of vehicles with that control more than 33 percent of an engine famsystem combination in that engine family ily will be equipped with an optional and will be designated by the Secretary item, the full estimated weight of that as to transmission type, fuel system and item shall be included in the curb weight inertia weight class.

computation for the entire engine fam(2) If an exhaust emission control ily. Where it is expected that 33 percent system-fuel evaporative emission control or less of the vehicles in an engine family system combination is used in only one will be equipped with an item of opengine family, an additional vehicle us tional equipment, no weight for that item ing that combination in that family will will be added in computing curb weight. be selected so that the durability data Optional equipment weighing less than 3

pounds per item need not be considered. (v) The fuel evaporative emission con

(2) Where it is expected that more trol system may be serviced at 12,000than 33 percent of an engine family will mile intervals (+250 miles) of schedule be equipped with an item of optional driving. equipment that can reasonably be ex (vi) Readjustment of the engine choke pected to influence exhaust or evapora mechanism or idle settings may be pertive emissions, then such items of formed only if there is a problem of stalloptional equipment shall actually be ing at stops. installed on all emission data and dura (vii) Leaks in the fuel system, engine bility data vehicles for such engine lubrication system and cooling system family.

may be repaired. $ 1201.90 Maintenance.

(viii) Any other engine or fuel system

maintenance or repairs will be allowed (a) (1) Maintenance on the engines only with the advance approval of the and fuel systems of durability vehicles Secretary. may be performed only under the follow (2) Repairs to vehicle components of ing provisions:

the durability data vehicle, other than (i) One major engine tuneup to manu the engine or fuel system, shall be perfacturer's specifications may be per- formed only as a result of part failure formed at 24,000 miles (+250 miles) of or vehicle system malfunction. scheduled driving with the following ex- (3) Allowable maintenance on emisception: On a vehicle with an engine sion data vehicles shall be limited to the displacement of 150 cubic inches or less adjustment of engine idle speed at the (or a rating of at least 1.20 maximum 4,000-mile test point. rated horsepower per cubic inch of dis (4) Where the Secretary agrees under placement) major engine tuneups may $ 1201.91 to a mileage accumulation of be performed at 12,000, 24,000, and 36,000 less than 50,000 miles for durability testmiles (+250 miles) of scheduled driving ing, he may modify the requirements of A major engine tuneup shall be restricted this paragraph. to the following:

(b) Complete emission tests (see (a) Replace spark plugs.

$$ 1201.71-1201.88) shall be run before (b) Inspect ignition wiring and replace and after any vehicle maintenance which as required.

may reasonably be expected to affect (c) Replace distributor breaker points emissions. These test data shall be supand condensor as required.

plied to the Secretary immediately after (d) Lubricate distributor cam.

the tests, along with a complete record (e) Check distributor advance and of all pertinent maintenance, including breaker point dwell angle and adjust as an engineering report of any malfunction required.

diagnosis and the corrective action taken. (f) Check automatic choke for free In addition, all test data and mainteoperation and correct as required.

nance reports shall be compiled and (g) Adjust carburetor idle speed and provided to the Secretary in accordance mixture.

with $ 1201.53. (h) Adjust drive belt tension on engine (c) If the Secretary determines that accessories.

maintenance or repairs performed have (i) Adjust valve lash if required. resulted in a substantial change to the

(j) Check exhaust heat control valve engine-system combination, the vehicle for free operation.

shall not be used as a durability data (k) Check engine bolt torque and vehicle. tighten as required.

$ 1201.91 Mileage accumulation and (ii) Spark plugs may be changed if a

emission measurements. persistent misfire is detected.

The procedure for mileage accumula(iii) Normal vehicle lubrication serv

tion will be the Durability Driving Schedices (engine and transmission oil change

ule as specified in Appendix D to this and oil filter, fuel filter, and air filter

part. A modified procedure may also be servicing) will be allowed at manufac used if approved in advance by the turer's recommended intervals.

Secretary. (iv) The crankcase emission control (a) Emission data vehicles: Each system may be serviced at 12,000-mile in emission data vehicle shall be driven tervals (+250 miles) of scheduled driv- 4,000 miles with all emission control sysing.

tems installed and operating. Emission


tests shall be conducted at zero miles and each test point. Maintenance may be 4,000 miles.

performed by the manufacturer under (b) Durability data vehicles: Each such conditions as the Secretary may durability data vehicle shall be driven, prescribe, with all emission control systems in

(3) The data developed by the Secrestalled and operating, for 50,000 miles or tary for the engine-system combination such lesser distance as the Secretary may shall be combined with any applicable agree to as meeting the objectives of this data supplied by the manufacturer on procedure. Emission measurements from other vehicles of that combination to a cold start shall be made at zero miles determine the applicable deterioration and at each 4,000-mile interval.

factors for the combination. In the case (c) All tests required by this subpart of a significant discrepancy between to be conducted after 4,000 miles of data developed by the Secretary and that driving or at any multiple of 4,000 miles submitted by the manufacturer, the Secmay be conducted at any accumulated retary's data shall be used in the determileage within 250 miles of 4,000 miles or mination of deterioration factors. the appropriate multiple of 4,000 miles,

$ 1201.92 Compliance with emission respectively.

standards. (d) The results of each emission test shall be supplied to the Secretary im

(a) The exhaust and fuel evaporative mediately after the test. Where a manu emission standards in the regulations in facturer conducts multiple tests at any this part apply to the average lifetime test point or any tests between test emissions of vehicles in public use. Prior points, data on these tests (including to certification, lifetime emissions can be voided tests) shall be provided immedi obtained by projection of test data to ately to the Secretary. In addition, all lifetime normal service. Normal service

data shall be compiled and provided in an urban area or its equivalent for to the Secretary in accordance with

100,000 miles is taken as the basis for $ 1201.33.

"lifetime emissions." (e) Whenever the manufacturer pro

b) It is expected that emission conposes to operate and test a vehicle which trol efficiency will change with mileage may be used for emission or durability accumulation on the vehicle. It is asdata, he shall provide the zero mile test sumed that the emission level of a vehicle data to the Secretary and make the

which has accumulated 50,000 miles in vehicle available for such testing under normal service is the average emission $ 1201.54 as the Secretary may require level of that vehicle over its lifetime. before beginning to accumulate mileage

(c) The procedure for determining on the vehicle. Failure to comply with compliance of a new light-duty motor this requirement will invalidate all test vehicle with exhaust and fuel evaporadata submitted for this vehicle.

tive emission standards is as follows: (f) Once a manufacturer begins to (1) Separate emission deterioration operate an emission data or durability factors shall be determined from the data vehicle, as indicated by compliance emission results of the durability data with paragraph (e) of this section, he vehicles for each engine-system combishall continue to run the vehicle to 4,000 nation. A separate factor shall be estabmiles or 50,000 miles, respectively, and lished for the combination for exhaust the data from the vehicle will be used in

HC, exhaust CO, and fuel evaporative the calculations under $ 1201.92. Discon

HC. tinuation of a vehicle shall be allowed (i) The applicable results to be used only with the written consent of the in determining the deterioration factors Secretary

for each combination shall be: (g) (1) The Secretary may elect to (a) All emission data from the tests operate and test any test vehicle during required under $ 1201.91(b), except the all or any part of the mileage accumula

zero mile tests. This shall include the oition and testing procedure. In such cases, ficial test results, as determined in the manufacturer shall provide the $ 1201.54, for all tests conducted on all vehicle(s) to the Secretary with all in durability vehicles of the combination formation necessary to conduct this selected under $ 1201.89(c), (including all testing.

vehicles elected to be operated by the (2) The test procedures (88 1201.71- manufacturer under $1201.89(c)(3)). 1201.88) will be followed by the Secretary. Where the Secretary has agreed to a The Secretary will test the vehicles at mileage less than 50,000 miles in accordance with $ 1201.91(b), the data for mile- the method of least squares, shall be ages greater than that actually run will drawn through these data points. The be determined by extrapolating the test interpolated 4,000- and 50,000-mile points data generated at lesser mileages.

on this line must be within the stand(b) All emission data from the tests

ards provided in $$ 1201.21 and 1201.22 or conducted before and after the mainte

the data will not be acceptable for use in nance provided in $ 1201.90(a) (1) (i). (ii) All applicable results shall be

calculation of a deterioration factor. plotted as a function of the mileage on (111) An exhaust emission deteriorathe system, rounded to the nearest mile, tion factor shall be calculated for each and the best fit straight lines, fitted by combination as follows:

exhaust emissions interpolated to 50,000 miles factor=

exhaust emissions interpolated to 4,000 miles



(iv) An evaporative emission deteri- eter. The exhaust gases generated during oration factor shall be calculated for engine operation are sampled continueach combination by substracting the ously for specific component analysis evaporative emissions interpolated to through the analytical train. The tests 4,000 miles from the evaporative emis- are applicable to engines equipped with sions interpolated to 50,000 miles.

catalytic or direct-flame afterburners, (2) (i) The exhaust emission test re induction system modifications, or other sults for each emission data vehicle shall systems, or to uncontrolled engines. be multiplied by the appropriate deteri- signed to determine hydrocarbon and oration factor: Provided, That if a de carbon monoxide concentrations during terioration factor as computed in sub a truck driving pattern in a metropolitan paragraph (1) (iii) of this paragraph is area as simulated on an engine dynaless than one, that deterioration factor mometer. The test consists of two warmshall be one for the purposes of this up cycles and two hot cycles. The aversubparagraph.

age concentrations for the warmup (ii) The evaporative emission test re cycles and the hot cycles are combined to sults for each combination shall be ad- yield the reported values. justed by addition of the appropriate de (c) When an engine is tested for exterioration factor: Provided, That if a haust emissions or is operated for duradeterioration factor as computed in sub

bility testing on an engine dynamometer paragraph (1) (iv) of this paragraph

the complete engine shall be used with is less than zero, that deterioration fac all accessories which might reasonably tor shall be zero for the purposes of this be expected to influence emissions to the subparagraph.

atmosphere installed and functioning. (3) The emissions to compare with the $ 1201.101 Gasoline fuel specifications. standard shall be the adjusted emissions (a) For exhaust emission testing, fuel of subparagraph (2) (i) and (ii) of this having specifications as shown in the paragraph for each emission data vehicle. table in $ 1201.71(a), or substantially

(4) Every test vehicle of an engine equivalent specifications approved by the family must comply with all applicable Secretary, shall be used. standards, as determined in subpara (b) For durability testing, fuel having graph (3) of this paragraph, before any specifications as shown in the table in vehicle in that family may be certified. $ 1201.71(b), or substantially equivalent Subpart I-Test Procedures for Engine

specifications approved by the Secretary,

shall be used. The octane rating of the Exhaust Emissions (Gasoline Fueled

fuel used shall be in the range recomHeavy Duty Engines)

mended by the engine manufacturer. $ 1201.100 Introduction.

The specifications of the fuel to be used

shall be reported in accordance with The procedures described in this subpart will be the test program to deter

$ 1201.51(b) (3). mine the conformity of new gasoline § 1201.102 Dynamometer operation fueled heavy duty engines with the ap

cycle and equipment. plicable standards set forth in this part. (a) (1) The following nine-mode cycle

(a) The test consists of prescribed shall be followed in dynamometer opersequences of engine operating conditions ation tests of gasoline fueled heavy duty to be conducted on an engine dynamom- engines.

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