AS ISO 9249:2021 Earth-moving machinery — Engine test code — Net power.
4 Standard reference conditions
The standard reference conditions shall be in accordance with ISO 15550:2002, Clause 5.
5 Tests
5.1 Test method
The test method shall be test method 2 as specified in ISO 15550:2002, 6.3.
5.2 Test conditions
The test conditions shall be in accordance with ISO 15550:2002, 6.3.4, together with the following:
a) Equipment and auxiliaries shall be installed in accordance with ISO 15550:2002, Table 1, column 3, including Table 1 footnotes. The fan shall include the entire fan system including the fan and all drive components such as the pump, lines and motor for a hydraulic fan. When the fan system is not fitted for the test then the power absorbed at 25 °C (ambient) shall be determined and subtracted from the measured engine power.
b) Other machine accessories connected to the engine but that are only necessary for the operation of the machine should be removed for the test. Where accessories cannot be removed, the power absorbed by them in the unloaded condition shall be determined and added to the measured engine power. The following list of examples is non-exhaustive:
1) machine control systems hydraulic system pumps; air compressor for machine systems;
3) air-conditioning system compressor;
4) transmission system pump(s);
5) mounted gearhox(es).
Where a disconnectable or progressive fan or blower is incorporated, the test is performed with the fan or blower disconnected or with the progressive fan running at maximum slip, as specified in ISO 15550:2002, Table 1. The intent of this condition is to state net power at the minimum nominal fan system power, when a disconnectable or progressive fan, blower, variable speed fan or ON-OFF fan is incorporated. Measure fan power at the normal operating range of the machine as a function of ambient temperature and load factor (i.e. not at start-up or other machine non-operating range condition).
6 Method of power correction
The method of power correction shall he in accordance with ISO 15550:2002, Clause 7.
The test may be carried out in an air-conditioned test room where the atmospheric conditions are controlled in order to maintain the correction factor as close to 1,0 as possible. In the case of engines with an automatic air temperature control, if the device is such that, at full load and at standard atmospheric conditions (see ISO 15550:2002, Clause 5), no heated air is added to the inlet air, the test shall he carried out with the device operating normally and the exponent of the temperature term in the correction factor, as specified in ISO 15550:2002, 7.3 or 7.4.2, shall be taken as zero (no temperature correction).
A calculation of the deductions is permissible in place of an actual test. The calculation method shall be accurate such that the engine net power ratings meet the requirements of Clause 9.AS ISO 9249 pdf download.