Division 3.6.3 Exhaust gas molar flow rate

Measurement

The exhaust gas molar flow rate may be measured by means of three systems:

1. (i)

   F1PDP molar flow rate. Based upon the speed at which the Positive Displacement Pump (PDP) operates for a test interval, the corresponding slope a ₁ , and intercept, a ₀ [-], as calculated with the calibration procedure set out in point 3.9.2, shall be used to calculate molar flow rate ṅ [mol/s] by means of equation (7-117):

   $ṅ={ƒ}_{\mathrm{n,PDP}}\times \frac{p_{\mathrm{in}}\times V_{\mathrm{rev}}}{R\times T_{\mathrm{in}}}$

   (7-117)

   with:

   $V_{\mathrm{rev}}=\frac{a_1}{f_{\mathrm{n,PDP}}\times \sqrt{\frac{p_{\mathrm{out}}-p_{\mathrm{in}}}{p_{\mathrm{in}}}}+a_0}$

   (7-118)

   where:

   a ₁

2. calibration coefficient [m³/s]

a ₀

3. calibration coefficient [m³/rev]

p _in, p _out

4. inlet/outlet pressure [Pa]

R

5. molar gas constant [J/(mol · K)]

T _in

6. inlet temperature [K]

V _rev

7. PDP pumped volume [m³/rev]

f _n.,PDP

8. PDP speed [rev/s]

SSV molar flow rate. Based on the C _d versus R _e ^# equation determined in accordance with point 3.9.4, the Sub-Sonic Venturi (SSV) molar flow rate during an emission test ṅ [mol/s] shall be calculated by means of equation (7-119):

Where: