86.144-94—Calculations; exhaust emissions.
The final reported test results shall be computed by use of the following formula:
Where:
(1)
YWM = Weighted mass emissions of each pollutant, i.e., THC, CO, THCE, NMHC, NMHCE, CH4, NOX, or CO2, in grams per vehicle mile.
(2)
Yct =Mass emissions as calculated from the “transient” phase of the cold start test, in grams per test phase.
(3)
Yht =Mass emissions as calculated from the “transient” phase of the hot start test, in grams per test phase.
(4)
Ys =Mass emissions as calculated from the “stabilized” phase of the cold start test, in grams per test phase.
(b)
The mass of each pollutant for each phase of both the cold start test and the hot start test is determined from the following:
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Code of Federal Regulations
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Code of Federal Regulations
Code of Federal Regulations
(A)
For gasoline-fuel, diesel-fuel and methanol fuel; DensityHC =16.33 g/ft 3 −carbon atom (0.5768 kg/m 3 −carbon atom), assuming an average carbon to hydrogen ratio of 1:1.85, at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(B)
For natural gas and liquefied petroleum gas-fuel; DensityHC =1.1771 (12.011 H/C (1.008)) g/ft 3 −carbon atom (0.04157(12.011 H/C (1.008))kg/m 3 −carbon atom), where H/C is the hydrogen to carbon ratio of the hydrocarbon components of the test fuel, at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
HCconc =Total hydrocarbon concentration of the dilute exhaust sample corrected for background, in ppm carbon equivalent, i.e., equivalent propane × 3.
Where:
(iv)
(A)
HCe =Total hydrocarbon concentration of the dilute exhaust sample or, for diesel-cycle (or methanol-fueled vehicles, if selected), average hydrocarbon concentration of the dilute exhaust sample as calculated from the integrated THC traces, in ppm carbon equivalent.
(v)
FID HCe =Concentration of total hydrocarbon plus methanol in dilute exhaust as measured by the FID, ppm carbon equivalent.
(vii)
CCH 3 OHe=Concentration of methanol in dilute exhaust as determined from the dilute exhaust methanol sample in ppm carbon. For vehicles not fueled with methanol, CCH 3 OHe equals zero.
(viii)
(A)
HCd =Total hydrocarbon concentration of the dilution air as measured, in ppm carbon equivalent.
(ix)
FID HCd =Concentration of total hydrocarbon plus methanol in dilution air as measured by the FID, ppm carbon equivalent.
(x)
CCH 3 OHd=Concentration of methanol in dilution air as determined from dilution air methanol sample in ppm carbon. For vehicles not fueled with methanol, CCH 3 OHd equals zero.
(ii)
DensityNO2 =Density of oxides of nitrogen is 54.16 g/ft3 (1.913 kg/m 3) assuming they are in the form of nitrogen dioxide, at 68 °F (20 °C) and 760 mm Hg (101.3kPa) pressure.
(iii)
(A)
NOxconc =Oxides of nitrogen concentration of the dilute exhaust sample corrected for background, in ppm.
Where:
(ii)
DensityCO = Density of carbon monoxide is 32.97 g/ft 3 (1.164 kg/m3), 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, in ppm.
Where:
(iv)
(A)
COe = Carbon monoxide concentration of the dilute exhaust volume corrected for water vapor and carbon dioxide extraction, in ppm.
(B)
COe = (1 − 0.01925CO2e -0.000323R)COem for petroleum fuel with hydrogen to carbon ratio of 1.85:1.
(C)
COe =[1−(0.01 0.005HCR) CO2e −0.000323R]COem for methanol-fuel or natural gas-fuel or liquefied petroleum gas-fuel, where HCR is hydrogen-to-carbon ratio as measured for the fuel used.
(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)
(A)
CO2conc = Carbon dioxide concentration of the dilute exhaust sample corrected for background, in percent.
(ii)
DensityCH3OH =Density of methanol is 37.71 g/ft 3 -carbon atom (1.332 kg/m 3 -carbon atom), at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
Where:
(xiii)
AVS=Volume of absorbing reagent (deionized water) in impinger through which methanol sample from dilute exhaust is drawn, ml.
(xiv)
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 - carbon atom (1.249 kg/m 3 -carbon atom), at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
HCHOconc = Formaldehyde concentration of the dilute exhaust corrected for background, in 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.
(ii)
For methanol-fueled vehicles, where fuel composition is CX Hy Oz as measured, or calculated, for the fuel used:
Code of Federal Regulations
Where:
(ix)
(A)
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)).
Where:
(x)
Vo =Volume of gas pumped by the positive displacement pump, in cubic feet (m 3) per revolution. This volume is dependent on the pressure differential across the positive displacement pump.
(xi)
N=Number of revolutions of the positive displacement pump during the test phase while samples are being collected.
(xiii)
P4 =Pressure depression below atmospheric measured at the inlet to the positive displacement pump, in mm Hg (kPa) (during an idle mode).
(xiv)
Tp =Average temperature of dilute exhaust entering positive displacement pump during test, °R(°K).
(A)
For gasoline-fuel and diesel-fuel; DensityNMHC =16.33 g/ft 3 -carbon atom (0.5768 kg/m 3 -carbon atom), assuming an average carbon to hydrogen ratio of 1:1.85 at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(B)
For natural gas and liquefied petroleum gas fuel; DensityNMHC =1.1771(12.011 H/C(1.008))g/ft 3 -carbon atom (0.04157(12.011 H/C(1.008))kg/m 3 -carbon atom), where H/C is the hydrogen to carbon ratio of the non-methane hydrocarbon components of the test fuel, at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(iii)
(A)
CH4conc = Methane concentration of the dilute exhaust sample corrected for background, in ppm carbon equivalent.
Where:
(ii)
DensityCH4 =Density of methane is 18.89 g/ft 3 -carbon atom (0.6672 kg/m 3 -carbon atom), at 68 °F (20 °C) and 760 mm Hg (101.3 kPa) pressure.
(d)
For petroleum-fueled vehicles, example calculation of mass values of exhaust emissions using positive displacement pump:
(1)
For the “transient” phase of the cold start test assume the following: Vo = 0.29344 ft 3 rev; N = 10,485; R = 48.0 pct; Ra = 48.2 percent; PB = 762 mm Hg; Pd = 22.225 mm Hg; P4 = 70 mm Hg; Tp = 570 °R; HCe = 105.8 ppm, carbon equivalent; NOxe = 11.2 ppm; COem = 306.6 ppm; CO2e = 1.43 percent; CH4e = 10.74 ppm; HCd = 12.1 ppm; NOxd = 0.8 ppm; COdm = 15.3 ppm; CO2d = 0.032 percent; CH4d = 2.20 ppm; Dct = 3.598 miles.
Then:
(2)
For the stabilized portion of the cold start test assume that similar calculations resulted in the following:
(3)
For the “transient” portion of the hot start test assume that similar calculations resulted in the following:
(i)
HCwm = 0.43[(4.027 0.62)/(3.598 3.902)] 0.57[(0.51 0.62)/(3.598 3.902)] = 0.352 gram per vehicle mile.
(ii)
NOxwm = 0.43[(1.389 1.27)/(3.598 3.902)] 0.57[(1.38 1.27)/(3.598 3.902)] = 0.354 gram per vehicle mile.
(iii)
COwm = 0.43[(23.96 5.98)/(3.598 3.902)] 0.57[(5.01 5.98)/(3.598 3.902)] = 2.55 grams per vehicle mile.
(iv)
CO2wm = 0.43[(1886 2346)/(3.598 3.902) 0.57[(1758 2346)/(3.598 3.902)] = 555 gram per vehicle mile.
(v)
NMHCwm = 0.43[(3.655 0.50)/(3.598 3.902)] 0.57[(0.44 0.50)/(3.598 3.902)] = 0.310 gram per vehicle mile.
(e)
For methanol-fueled vehicles with measured fuel composition of CH3.487 O0.763, example calculation of exhaust emissions using positive displacement pump:
(1)
For the “transient” phase of the cold start test assume the following: V0 =0.29344 ft 3 rev; N=25,801; R=37.5 pct; Ra=37.5 percent; PB =725.42 mm Hg; Pd =22.02 mm Hg; P4 =70 mm Hg; Tp 570 deg.R; FID HCe =14.65 ppm, carbon equivalent; r=0.788; TEM =527.67 deg.R; VEM =0.2818 ft 3; CS1 =7.101; AVS1 =15.0 ml; CS2 =0.256; AVS2 =15.0 ml; TDM =527.67 deg.R; VDM =1.1389 ft 3; CD1 =0.439; AVD1 =15.0 ml; CD2 =0.0; AVD2 =15.0 ml; CFDE =8.970 µg/ml; VAE =5.0 ml; Q=0.1429; TEF =527.67 deg.R; VSE =0.2857 ft 3; CFDA =0.39 µg/ml; VAA =5.0 ml; TDF =527.67 deg.R; VSA =1.1043 ft 3; NOX.=5.273 ppm; COem =98.8 ppm; CO2e =0.469 pct; CH4e =2.825 ppm; FID HCd =2.771 ppm; NOX.=0.146 ppm; COdm =1.195 ppm; CO2d =0.039 percent; CH4d =2.019 ppm; Dct=3.583 miles.
Then:
(viii)
DF = 100(1/[1 (3.487/2) 3.76(1 (3.487/4) − (0.763/2))])/0.469 (6.092 96.332 10.86 0.664)(10−4) = 24.939.
(xxviii)
NMHCEmass =0.263 (13.8756/32.042)(2.44) (13.8756/ 30.0262)(0.1405)=1.39 grams per test phase.
(2)
For the stabilized portion of the cold start test assume that similar calculations resulted in the following:
(3)
For the “transient” portion of the hot start test assume that similar calculations resulted in the following:
(i)
THCEwm = (0.43) × (1.473 0.143)/(3.583 3.854) (0.57) × (0.488 0.143)/(3.577 3.854) = 0.142 grams as carbon equivalent per mile.
(ii)
NOxwm = (0.43) × (1.505 0.979)/(3.583 3.854) (0.57) × (1.505 0.979)/3.577 3.854) = 0.344 grams per mile.
(iii)
COwm = (0.43) × (18.983 0.365)/(3.583 = 3.854) (0.57) × (3.696 0.365)/(3.577 3.854) = 1.43 grams per mile.
(iv)
CO2wm = (0.43) × (1353 1467)/(3.583 3.854) (0.57) × (1179 1467)/(3.577 3.854) = 366 grams per mile.
(v)
NMHCEwm = (0.43) × (1.386 0.113)/(3.583 3.854) (0.57) × (0.426 = 0.113)/(3.577 3.854) = 0.128 grams per mile.