# Title 40

## SECTION 1065.247

### 1065.247 Diesel exhaust fluid flow rate.

§ 1065.247 Diesel exhaust fluid flow rate.(a) *Application.* Determine diesel exhaust fluid flow rate
over a test interval for batch or continuous emission sampling
using one of the three methods described in this section.

(b) *ECM.* Use the ECM signal directly to determine diesel
exhaust fluid flow rate. You may combine this with a gravimetric
scale if that improves measurement quality. Prior to testing, you
may characterize the ECM signal using a laboratory measurement and
adjust the ECM signal, consistent with good engineering
judgment.

(c) *Flow meter.* Measure diesel exhaust fluid flow rate
with a flow meter. We recommend that the flow meter that meets the
specifications in Table 1 of § 1065.205. Note that your overall
system for measuring diesel exhaust fluid flow must meet the
linearity verification in § 1065.307. Measure using the following
procedure:

(1) Condition the flow of diesel exhaust fluid as needed to prevent wakes, eddies, circulating flows, or flow pulsations from affecting the accuracy or repeatability of the meter. You may accomplish this by using a sufficient length of straight tubing (such as a length equal to at least 10 pipe diameters) or by using specially designed tubing bends, straightening fins, or pneumatic pulsation dampeners to establish a steady and predictable velocity profile upstream of the meter. Condition the flow as needed to prevent any gas bubbles in the fluid from affecting the flow meter.

(2) Account for any fluid that bypasses the engine or returns from the engine to the fluid storage tank.

(d) *Gravimetric scale.* Use a gravimetric scale to
determine the mass of diesel exhaust fluid the engine uses over a
discrete-mode test interval and divide by the time of the test
interval.