Title 40

PART 86 APPENDIX III



Appendix III to Subpart S of Part 86 - As-Received Inspection

40:21.0.1.1.5.19.1.88.57 : Appendix III

Appendix III to Subpart S of Part 86 - As-Received Inspection

Items to be recorded at time of Initial Inspection of Vehicle -

1. Date of Inspection 3. Test Group 4. Evaporative/refueling Family 5. Vehicle model 6. Odometer Reading 7. Build Date 8. MIL light on/off status 9. Readiness code status 10. Stored OBD codes 11.Any conditions referenced in appendix II to this subpart which result in vehicle being rejected from program.


Appendix III to Part 86 - Constant Volume Sampler Flow Calibration

40:21.0.1.1.5.21.1.12.61 : Appendix III

Appendix III to Part 86 - Constant Volume Sampler Flow Calibration

The following calibration procedure outlines the equipment, the test setup configuration, and the various parameters which must be measured to establish the flow rate of the constant volume sampler pump. All the parameters related to the pump are simultaneously measured with the parameters related to a flowmeter which is connected in series with the pump. The calculated flow rate (ft 3/rev@ pump inlet absolute pressure and temperature) can then be plotted versus a correlation function which is the value of a specific combination of pump parameters. The linear equation which relates the pump flow and the correlation function is then determined. In the event that a CVS has a multiple speed drive, a calibration for each range should be performed.

This calibration procedure is based on the measurement of the absolute values of the pump and flowmeter parameters that relate the flow rate at each point. Three conditions must be maintained to assure the accuracy and integrity of the calibration curve. First, the pump pressures should be measured at taps on the pump rather than at the external piping on the pump inlet and outlet. Pressure taps that are mounted at the top and bottom center of the pump drive headplate are exposed to the actual pump cavity pressures, and therefore reflect the absolute pressure differentials. Secondly, temperature stability must be maintained during the calibration. The laminar flowmeter is sensitive to inlet temperature oscillations which cause the data points to be scattered. Gradual changes (±2 °F) in temperature are acceptable as long as they occur over a period of several minutes. Finally, all connections between the flowmeter and the CVS pump must be absolutely void of any leakage.

During a CVS emissions test the measurement of these same pump parameters enables the user to calculate the flow rate from the calibration equation.

After the calibration curve has been obtained, a verification test of the entire system can be performed by injecting a known mass of gas into the system and comparing the mass indicated by the system to the true mass injected. An indicated error does not necessarily mean that the calibration is wrong, since other factors can influence the accuracy of the system.

Equipment:

The following list of equipment will be needed to perform this calibration procedure. Figure 1 illustrates a typical equipment arrangement used for calibration. All of the equipment involved should conform to the range and accuracy as specified in Figure 1.

Equipment List:

1. LFE - Laminar Flowmeter

2. Micromanometer

3. Thermometer

4. Timer

5. U-Tube Manometers

6. Temperature Indicator with type J Thermocouples

7. A variable flow restrictor with appropriate piping to connect the CVS pump and LFE.

After the system has been connected as shown in Figure 1, set the variable restrictor in the wide open position and run the CVS pump for twenty minutes. Record the calibration data.

Calibration Data Measurements

Parameter Symbol Units Tolerance
Barometric pressure (corrected) PB “Hg ±.01 “Hg.
Ambient temperature TA °F ±.5 °F.
Air Temperature into LFE ETI °F ±.1 °F.
Pressure depression upstream of LFE EPI “H20 ±.1“H20.
Pressure drop across the LFE matrix EDP “H20 ±.005“H20.
Air temperature at CVS pump inlet PTI °F ±.5 °F.
Pressure depression at CVS pump inlet PPI “Fluid ±.05“Fluid.
Specific gravity of manometer fluid Sp. Gr.
Pressure head at CVS pump outlet PPO “Fluid ±.05“Fluid.
Air temperature at CVS pump outlet (optional) PTO °F ±.5 °F.
Pump revolutions during test period N Revs None.
Elapsed time for test period t Seconds ±.05 Seconds.