86.1342-90—Calculations; exhaust emissions.
(a)
The final reported transient emission test results should be computed by using the following formula:
Where:
(1)
AWM = Weighted mass emission level (HC, CO, CO2. or NOX) in grams per brake horsepower-hour and, if appropriate, the weighted mass total hydrocarbon equivalent, in grams per brake horsepower-hour.
(2)
gC = Mass emission level in grams or grams carbon mass equivalent, measured during the cold start test.
(3)
gH = Mass emission level in grams or grams carbon mass equivalent, measured during the hot start test.
(4)
BHP − hrC = Total brake horsepower-hour (brake horsepower integrated over time) for the cold start test.
(5)
BHP-hrH = Total brake horsepower-hour (brake horsepower integrated over time) for the hot start test.
(b)
The mass of each pollutant for the cold start test and the hot start test for bag measurements and diesel continuously heated sampling system measurements is determined from the following equations:
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(c)
The mass of each pollutant for the cold start test and the hot start test for flow compensated sample systems is determined from the following equations:
(ii)
DensityHC = Density of hydrocarbons = 16.33 g/ft 3 (0.5768 kg/m 3) for gasoline and the gasoline fraction of methanol-fuel, and may be used for petroleum and the petroleum fraction of methanol diesel fuel if desired, 16.42 g/ft 3 (0.5800 kg/m 3) for #l petroleum diesel fuel and 16.27 g/ft 3 (0.5746 kg/m 3) for #2 diesel, assuming an average carbon to hydrogen ratio of 1:1.85 for gasoline, 1:1.93 for #1 petroleum diesel fuel and 1:1.80 for #2 petroleum diesel fuel at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
HCconc = Hydrocarbon concentration of the dilute exhaust sample corrected for background, in ppm carbon equivalent (i.e., equivalent propane × 3).
Where:
(iv)
(A)
HCe = Hydrocarbon concentration of the dilute exhaust bag sample or, for diesel continuous heated sampling systems, average hydrocarbon concentration of the dilute exhaust sample as determined from the integrated HC traces, in ppm carbon equivalent. For flow compensated systems (HCe )i is the instantaneous concentration.
HCe = FID HCe − (r)CCH3OHe
(v)
FID HCe = Concentration of hydrocarbon plus methanol in dilute exhaust as measured by the FID, ppm carbon equivalent.
(vii)
CCH3OHe = Concentration of methanol in dilute exhaust as determined from the dilute exhaust methanol sample, ppm carbon.
(viii)
(A)
HCd = Hydrocarbon concentration of the dilution air as measured, in ppm carbon equivalent.
(ix)
FID HCd = Concentration of hydrocarbon plus methanol in dilution air as measured by the FID, ppm carbon equivalent.
(x)
CCH3OHd = Concentration of methanol in dilution air as determined from dilution air methanol sample in ppm carbon.
(ii)
DensityNO2 = Density of oxides of nitrogen is 54.16 g/ft 3 (1.913 kg/m 3 ), assuming they are in the form of nitrogen dioxide, at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
NOxconc = Oxides of nitrogen concentration of the dilute exhaust sample corrected for background, in ppm.
Where:
(iv)
NOxe = Oxides of nitrogen concentration of the dilute exhaust bag sample as measured, in ppm. For flow compensated sample systems (NOxe )i is the instantaneous concentration.
(ii)
DensityCO = Density of carbon monoxide is 32.97 g/ft 3 (1.164 kg/m 3 ), at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
COconc = Carbon monoxide concentration of the dilute exhaust sample corrected for background, water vapor, and CO2 extraction, ppm.
Where:
(iv)
COe = Carbon monoxide concentration of the dilute exhaust bag sample volume corrected for water vapor and carbon dioxide extraction, in ppm. For flow compensated sample systems (COe )i is the instantaneous concentration.
(v)
(A)
COe = (1 − 0.01925CO2. − 0.000323R)COem for gasoline and petroleum diesel fuel, with hydrogen to carbon ratio of 1.85:1.
(B)
COe = [1 − (0.01 0.005HCR) CO2. − 0.000323R] COem for methanol fuel, where HCR is hydrogen to carbon ratio as measured for the fuel used.
Where:
(vii)
(A)
CO2. = Carbon dioxide concentration of the dilute exhaust bag sample, in percent, if measured. For flow compensated sample systems, (CO2.)i is the instantaneous concentration. For cases where exhaust sampling of CO2 is not performed, the following approximation is permitted:
Where:
(viii)
(A)
COd = Carbon monoxide concentration of the dilution air corrected for water vapor extraction, in ppm.
Where:
Code of Federal Regulations
(ii)
Density CO2 = Density of carbon dioxide is 51.81 g/ft 3 (1.830 kg/m 3 ), at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
CO2conc = Carbon dioxide concentration of the dilute exhaust sample corrected for background, in percent.
Where:
(ii)
DensityCH3OH = Density of methanol is 37.71 g/ft 3 (1.332 kg/m 3 ), at 68 °F (20 °C) and 760 mm Hg (101.3kPa) pressure.
(iii)
(A)
CH3 OHconc = Methanol concentration of the dilute exhaust corrected for background, in ppm.
Where:
(xv)
AVS = Volume of absorbing reagent (deionized water) in impinger through which methanol sample from dilute exhaust is drawn, ml.
(xvi)
AVD = Volume of absorbing reagent (deionized water) in impinger through which methanol sample from dilution air is drawn, ml.
(ii)
DensityHCHO = Density of formaldehyde is 35.36 g/ft 3 (1.249 kg/m 3 ), at 68 °F (20 °C) and 760 mmHg (101.3 kPa) pressure.
(iii)
(A)
HCHOconc = Formaldehyde concentration of the dilute exhaust corrected for background, ppm.
Where:
(vi)
CFDE = Concentration of DNPH derivative of formaldehyde from dilute exhaust sample in sampling solution, µg/ml.
(xii)
CFDA = Concentration of DNPH derivative of formaldehyde from dilution air sample in sampling solution, µg/ml.
Code of Federal Regulations
(ii)
For gasoline-fueled and methanol-fueled diesel engines: KH = 1/[1 − 0.0047 (H − 75)] (or for SI units, KH = 1/[1 − 0.0329(H − 10.71)]).
(iii)
For petroleum-fueled and methanol-fueled diesel engines: KH = 1/[1 − 0.0026 (H − 75)] (or for SI units = 1/[1 − 0.0182 (H − 10.71)]).
Where:
(iv)
(A)
H = Absolute humidity of the engine intake air in grains (grams) of water per pound (kilogram) of dry air.
(2) For SI units,
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(9)
(i)
Vmix = Total dilute exhaust volume in cubic feet per test phase corrected to standard conditions (528 °R) (293 °K) and 760 mm Hg (101.3 kPa).
(ii)
(Vmix )i = Instantaneous dilute exhaust volumetric flow rate (for compensated flow systems), ft 3 /sec.
Where:
(vi)
Vo = Volume of gas pumped by the positive displacement pump, in cubic feet (cubic meters) per revolution. This volume is dependent on the pressure differential across the positive displacement pump.
(vii)
N = Number of revolutions of the positive displacement pump during the test phase while samples are being collected.
(ix)
P4 = Pressure depression below atmospheric measured at the inlet to the positive displacement pump, in mm Hg (kPa) (during an idle mode).
(x)
Tp = Average temperature of dilute exhaust entering positive displacement pump during test, °R (°K).
Cold start cycle test results | Hot start cycle test results | |
---|---|---|
Vmix | 6924 ft 3 | 6873 ft3. |
R | 30.2 percent | 30.2 percent. |
Ri | 30.2 percent | 30.2 percent. |
PB | 735 mm Hq | 735 mm Hg. |
Pd | 22.676 mm Hq | 22.676 mm Hq. |
HCe | 132.07 ppm C equiv | 86.13 ppm C equiv. |
NOxe | 7.86 ppm | 10.98 ppm. |
COem | 171.22 ppm | 114.28 ppm. |
CO2. | 0.178 percent | 0.381 percent. |
HCd | 3.60 ppm C equiv | 8.70 ppm C equiv. |
NOd | 0.0 ppm | 0.10 ppm. |
COdm | 0.89 ppm | 0.89 ppm. |
C02. | 0.0 percent | 0.038 percent. |
BHP-hr | 0.259 | 0.347. |
Then:
= [(43.478)(30.2)(22.676)]/[735−
(22.676)(30.2)/100]
= 41 grains of water per pound of dry air.
= [1−0.01925(.178)−
0.000323(30.2)]171.22
= 169.0 ppm
0.881 ppm
Code of Federal Regulations
= 64.390
= 132.07−3.6[1−(1/64.390)]
= 128.5 ppm
Code of Federal Regulations
= 14.53 grams
= 7.86−0.0[1−(1/64.390)]
= 7.86 ppm
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= 2.54 grams
= 169.0−.881[1−(1/64.390)]
= 168.0 ppm
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= 38.35 grams
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Code of Federal Regulations
221
grams
(f)
The final reported brake-specific fuel consumption (BSFC) shall be computed by use of the following formula:
Where:
(1)
BSFC = brake-specific fuel consumption in pounds of fuel per brake horsepower-hour (lbs/BHP-hr).
(4)
BHP-hrC = total brake horsepower-hours (brake horsepower integrated with respect to time) for the cold start test.
(5)
BHP-hrH = total brake horsepower-hours (brake horsepower integrated with respect to time) for the hot start test.
(g)
(1)
The mass of fuel for the cold start and hot start test is determined from mass fuel flow measurements made during the tests, or from the following equation:
Code of Federal Regulations
Where:
Cold start cycle test results | Hot start cycle test results | |
---|---|---|
BHP-hr | 6.945 | 7.078 |
α | 1.85 | 1.85 |
HCmass (grams) | 37.08 | 28.82 |
COmass (grams) | 357.69 | 350.33 |
C02mass (grams) | 5,419.62 | 5,361.32 |
Then:
(i)
Gs for cold start test = [12.011/(12.011 (1.008)(1.85))](37.08) 0.429(357.69) 0.273(5419.62) = 1665.10 grams
(ii)
Gs for hot start test = [12.011/(12.011 (1.008)(1.85))](28.82) 0.429(350.33) 0.273(5361.32) = 1638.88 grams
BSFC (1/7)(4.24) =(6/7)(4.17)/(1/7)(6.945) (6/7)(7.078) = 0.592 lbs of fuel/BHP−hr
(i)
For dilute sampling systems which require conversion of as-measured dry concentrations to wet concentrations, the following equation shall be used for any combination of bagged, continuous, or fuel mass-approximated sample measurements (except for CO measurements made through conditioning columns, as explained in paragraph (d)(3) of this section):
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Where:
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See paragraph (d)(1) of this section for α values.
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See paragraph (d)(1) of this section for α values.
(3)
(i)
H = Absolute humidity of the CVS dilution air, in grains (grams) of water per lb (kg) of dry air.
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(5)
Pd = Saturated vapor pressure, in mm Hg (kPa) at the ambient dry bulb temperature of the CVS dilution air.