Dynamometer Test Monitoring Essentials

Accurate, consistent, repeatable results are the reason for dynamometer testing.  Many factors are involved in testing, so monitoring your test is critical to producing accurate results.  Below are different types of monitoring considerations you should consider when testing.

Limit Monitoring

Programmed tests may provide a false sense of comfort. The operator is not directly in control of
the test and therefore may tend to pay less attention to the test.

• An engine, particularly a high-performance engine, can always develop a problem with possible disastrous effects on the engine and/or test system.
• During automated tests, the operator should continuously monitor all operating parameters and be ready to intervene in case of trouble.
• Always pay attention to the test because some error conditions are not measurable by the system
  (For Example: A small leak in a high-pressure fuel line will cause a fine fuel spray that is not detectable by the test system but may quickly result in a catastrophic fire)

SuperFlow systems include special safety-limit programs that can take over most of the monitoring tasks.

Environmental Monitoring

Test results are only valid and repeatable if the test is performed in controlled operating conditions. Unless the automated test is programmed to verify these conditions, it is always up to the operator to make sure the test is initiated at the same operating conditions from test to test.

For example, if two back-to-back, identical acceleration tests are performed, but the engine oil temperature is 20 degrees higher at the start of the second test (due to the heat load of the first test), then the results of the second test will not be directly comparable to the first test.

In general, these parameters should be monitored for repeatable test data:

• Oil and coolant temperatures
• Air inlet temperature
• Fuel supply pressure and fuel temperature
• Battery voltage
• Exhaust back pressure and exhaust gas concentration in the test room
• Aftercooler temperature (on turbocharged engines)

Again, it may be possible to program these parameters into the automated test; in most cases, however, the operator is responsible for checking the environmental conditions.