AS ISO 9249:2021 – Earth-moving machinery – Engine testcode -Net power.
engine adjustment
physical procedure of modifying an engine for the purpose of adapting it to deliver a power adjusted to a different set of ambient conditions, such as by moving the limiting fuel stop, re-matching the turbocharger, changing the fuel injection timing or other physical changes
Note 1 to entry: Once the modifications have been completed the engine Is an adjusted engine.
ISOURCE: ISO 15550:2002, definition 3.2.11
engine speed
number of revolutions of the crankshaft in a given period of time
ISOURCE: ISO 2710-1:2000, definition 11.11
fuel delivery
metered volume (mass) of fuel delivered by a fuel injection system during one working cycle
Note Ito entry: Adapted from ISO 7876-1:1990, defInition 10.24.
general term describing the magnitude of the “powcr or torque” demanded from the engine by Its driven machinery and usually expressed relative to a declared power or torque
Note ito entry: The term “load” is physically imprecise and should be avoided. For quantitative purposes the termS power or torque’ should be used, instead of “load. together with a statement aispeed.
[SOURCE: ISO 15550:2002. definition 3.3.111
net power
power obtained on a test bed at the end of the crankshaft or its equivalent, at the corresponding engine speed, with the equipment and auxiliaries listed in ISO 15550:2002, Table 1. column 2. and required In column 3 (fitted for engine net power test)
Note Ito entry: If the power measurement can only be carried out with a mounted gearbox, the losses in the gearbox should be added to the measured power to give the net engine power.
Note 2 to entry: Adapted from ISO 15550:2002. deflnitton
net torque
torque transmitted on a test bed at the end of the crankshaft or its equivalent, at the corresponding engine speed, with the equipment and auxiliaries listed in ISO 15550:2002. Table I, column 2, and required In column 3 (fitted for engine net power test)
Note Ito entry: Adapted from ISO 15550:2002.delinition3.3.12.
power correction
calculation procedure by which a power value determined under engine test conditions is modified so that it represents the power value expected under other operating or reference conditions without any engine adjustment
[SOURCE: ISO 15550:2002, definition 3.3.101
Note ito entry: In this case, the power and performance parameters may vary as a function olamblent conditions (see ISO 15550:2002, Clause 7).
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 I, column 3. IncludIng Table I 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 theni 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 system(s) hydraulic system pumps; air compressor for machine systems;
3) air-conditioning system compressor;
4) transmission system pump(s
5) mounted gearbox(es).
Where a disconnectable or progressive fan or blower is incorporated, the test is performed with the tan 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 [an power at the normal operating range o[the machine as a [unction o[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 be 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 be carried out with the device operating normally and the exponent of the temperature term in he correction factor, as specified In ISO 15550:2002,7.3 or 7.4,2. shall be taken as zero (no temperature correction).