New Holland SmartTrax T8.320 Service Manual page 80

Engine - General information - Dynamometer testing guidelines
One of the main services which a dealership provides is verifying tractor engine and Power Take-Off (PTO) perfor-
mance with a dynamometer. As agricultural engine technology has become more sophisticated, dynamometer testing
of these machines must become more sophisticated and consistent to deal with the advancements.
During manufacturing, the engine for each machine is run on an engine dynamometer to ensure that the power
produced from the engine is within the specified parameters. These tests are performed under strictly controlled con-
ditions which can be difficult to replicate in a dealership environment.
For example, the following conditions in detail are recorded when establishing the power output of an engine:
Humidity
Ambient air temperature
Atmospheric pressure (barometer)
Altitude
Any or all of these factors can affect the power output of an engine, so some tolerances must be applied to power
measurements from dynamometer testing at the dealership. Weather, air and fuel conditions affect tractor perfor-
mance.
As a general rule, remember:
• As air temperature DECREASES, e power INCREASES.
• As atmospheric pressure (barometer) DECREASES, power DECREASES.
• As altitude INCREASES, the power DECREASES about 2% for every 300 m (1500 ft) above 1500 m (5000 ft) for
turbo-charged engines.
• As fuel density INCREASES, power INCREASES.
• As fuel temperature INCREASES, power DECREASES.
A standard test procedure must be followed so that results from a dynamometer test are consistent and accurate.
These results can then be recorded and used for future comparison.
NOTE: The power/torque readings from a dynamometer test are the rate speed, full load, PTO power maximum torque
achieved by the tested tractor. These readings could be lower than the PTO power advertised for the tractor under
test, depending on tractor/engine equipment (parasitics) and the ambient environment test conditions. Also note,
maximum PTO power may be observed at an engine RPM less than the advertised rated engine RPM. For example,
while the rated engine RPM may be 2000 RPM, maximum PTO horsepower may be observed at 1800 RPM. This is
typically defined as peak power or power bulge.
Perform these actions if a dyno test shows low power
1. Check the fuel injection system for faults or a derate condition. Perform the corresponding fault code resolution
and rectify the problem.
2. Run the test a second time to collect comparative data. You must record the ambient air temperature, fuel tem-
perature, and water temperature.
3. Check all supply lines for restrictions, air ingress and cleanliness.
4. Check the air intake system and the filter(s) condition and cleanliness.
5. Run the test for a third time.
If the power is still not acceptable, escalate the concern with ASIST. Supply the following information:
• The completed dynamometer testing worksheet. See Engine - General information - Dyno test worksheet
(10.001)
• All other collected documentation such as dynamometer test results, dynamometer calibration, fault codes, service
actions taken, etc.
Engine - Engine and crankcase
Fuel temperature
Fuel specification
Fuel density
Dynamometer accuracy
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