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e-CFR data is current as of November 24, 2020

Title 40Chapter ISubchapter CPart 90Subpart D → Appendix


Title 40: Protection of Environment
PART 90—CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS
Subpart D—Emission Test Equipment Provisions


Appendix A to Subpart D of Part 90—Tables

Table 1—Symbols Used in Subpart D

Symbol Term Unit
COCarbon monoxide
CO2Carbon dioxide
NONitric oxide
NO2Nitrogen dioxide
NOXOxides of nitrogen
O2Oxygen
concConcentration (ppm by volume)ppm
fEngine specific parameter considering atmospheric conditions
FFCBFuel specific factor for the carbon balance calculation
FFDFuel specific factor for exhaust flow calculation on dry basis
FFHFuel specific factor representing the hydrogen to carbon ratio
FFWFuel specific factor for exhaust flow calculation on wet basis
GAIRWIntake air mass flow rate on wet basiskg/h
GAIRDIntake air mass flow rate on dry basiskg/h
GEXHWExhaust gas mass flow rate on wet basiskg/h
GFuelFuel mass flow ratekg/h
HAbsolute humidity (water content related to dry air)gr/kg
iSubscript denoting an individual mode
KHHumidity correction factor
LPercent torque related to maximum torque for the test modepercent
massPollutant mass flowg/h
nd,  iEngine speed (average at the i'th mode during the cycle)1/min
PsDry atmospheric pressurekPa
PdTest ambient saturation vapor pressure at ambient temperaturekPa
PGross power output uncorrectedkW
PAUXDeclared total power absorbed by auxiliaries fitted for the testkW
PMMaximum power measured at the test speed under test conditionskW
PiPi = PM,  i + PAUX,  i
PBTotal barometric pressure (average of the pre-test and post-test values)kPa
RaRelative humidity of the ambient airpercent
TAbsolute temperature at air inletC
TbeAir temperature after the charge air cooler (if applicable) (average)C
TcloutCoolant temperature outlet (average)C
TDdAbsolute dew point temperatureC
Td,  iTorque (average at the i'th mode during the cycle)N-m
TSCTemperature of the intercooled airC
TrefReference temperatureC
VEXHDExhaust gas volume flow rate on dry basism3/h
VAIRWIntake air volume flow rate on wet basism3/h
PBTotal barometric pressurekPa
VEXHWExhaust gas volume flow rate on wet basism3/h
WFWeighing factor
WFEEffective weighing factor

Table 2—Measurement Calibration Accuracy and Frequency

No.ItemPermissible deviation from reading*Calibration frequency
Non-idleIdle
1Engine speed±2 %SameMonthly or within one month prior to the certification test.
2Torque±2 %Monthly or within one month prior to the certification test.
3Fuel consumption±2 %±5%Monthly or within one month prior to the certification test.
4Air consumption±2 %±5%As required.
5Coolant temperature±2 °CSameAs required.
6Lubricant temperature±2 °CSameAs required.
7Exhaust back pressure±5 %SameAs required.
8Inlet depression±5 %SameAs required.
9Exhaust gas temperature±15 °CSameAs required.
10Air inlet temperature (combustion air)±2 °CSameAs required.
11Atmospheric pressure±0.5 %SameAs required.
12Humidity (combustion air) (relative)±3.0 %SameAs required.
13Fuel temperature±2 °CSameAs required.
14Temperature with regard to dilution system±2 °CSameAs required.
15Dilution air humidity±3 % absoluteSameAs required.
16HC analyzer±2 %**SameMonthly or within one month prior to the certification test.
17CO analyzer±2 %**SameMonthly or within one month prior to the certification test.
18NOX analyzer±2 %**SameMonthly or within one month prior to the certification test.
19NOX converter check90 %SameMonthly or within one month prior to the certification test.
20CO2 analyzer±2 %**SameMonthly or within one month prior to the certification test.

*All accuracy requirements pertain to the final recorded value which is inclusive of the data acquisition system.

**If reading is under 100 ppm then the accuracy shall be ±2 ppm.

Table 3—Test Fuel Specifications

ItemPropertyTolerancesProcedure (ASTM)1
Sulfur, ppm max.339D 2622-92
Benzene, max. %1.5D 3606-92
RVP, psi8.7±0.2D 5191-93a
Octane, R + M/287.3±0.5D 2699-92
D 2700-92
IBP, °C32.8±11.0D 86-93
10 % point, °C53.3±5.5D 86-93
50 % point, °C103.3±5.5D 86-93
90 % point, °C165.6±5.5D 86-93
End Point, max. °C212.8D 86-93
Phosphorus, g/liter, max.0.02D 3231-89
Lead, g/liter, max.0.02
Manganese, g/liter, max.0.004
Aromatics, %32.0±4.0D 1319-89
Olefins, %9.2±4.0D 1319-89
Saturates, %RemainderD 1319-89

1All ASTM procedures in this table have been incorporated by reference. See §90.7.

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