Section 14 - Engine Testing - Group 14 Engine Testing - General Information M11 Page 14-5 Caution: Do not shut off the engine immediately after the run-in is completed. Allow the engine to cool by operating at low idle for a minimum of 3 minutes to avoid internal component damage. Fuel Flow Measurement on Engine or Chassis Dynamometer Accurate fuel flow measurement is important for evalua- tion of engine performance and troubleshooting on an engine or chassis dynamometer. The only way accurate fuel flow measurement can be obtained is through proper use of the available equipment.
Below is a description of the fuel measuring device, available from Cummins En- gine Company, along with installation and operation rec- ommendations. The fuel measuring device, Part No. 3376375, can be used with either a chassis or engine dynamometer. Installation When installing the fuel measuring device, it is important to reduce the amount of air that can be introduced into the system when the device is not in use. Therefore, the plumbing used must include non-restrictive shutoff valves, such as ballcock valves, to contain fuel in the device after each use. Additional installation considerations are: The fuel measuring device, Part No.
3376375, must be mounted vertically to provide accuracy and proper operation. A separate fuel supply for use on the dynamometer is recommended. All fuel used in the measuring device must be clean for consistent operation. Care must be taken to reduce fuel line restriction to and from the engine. Minimum recommended hose sizes are No. 10 for the engine fuel inlet, and No. 8 for the engine fuel drain. The length of either hose must not exceed 15 feet. For accurate fuel consumption or flow measurement while testing on a chassis dynamometer, it is rec- ommended to use a fuel cooler to maintain inlet temperature to the fuel gear pump at 49°C [120°F] or below.