BS ISO 1585:2020 pdf download.Road vehicles — Engine test code — Net power.
4 Accuracy of measuring equipment and instruments
4.1 Torque
The dynamometer torque-measuring system shall have an accuracy within ±1 % in the range of scale values required for the test.
4.2 Engine speed (rotational frequency)
The engine speed (rotational frequency) measuring system shall have an accuracy of ±0,5 %.
4.3? Fuel? flow
The fuel flow measuring system shall have an accuracy of ±1 %.
4.4 Fuel temperature
The fuel temperature measuring system shall have an accuracy of ±2 K.
4.5 Air temperature
The air temperature measuring system shall have an accuracy of ±1 K.
4.6 Barometric pressure
The barometric pressure measuring system shall have an accuracy of ±100 Pa.
NOTE 1 Pa = 1 N/m 2 .
4.7 Back pressure in exhaust system
The system used to measure the back pressure in the exhaust system shall have an accuracy of ±200 Pa.
The measurement shall be made subject to footnote b of Table 1.
5.3 Test conditions
5.3.1 The net power test shall consist of a run at full throttle for spark-ignition engines and at the fixed full-load fuel injection pump setting for compression-ignition engines, the engine being equipped as specified in Table 1.
5.3.2 Performance data shall be obtained under stabilized operating conditions, with an adequate fresh air supply to the engine.
Engines shall have been run•in, started and warmed up in accordance with the manufacturer’s recommendations. Combustion chambers may contain deposits, but in limited quantity. Test conditions such as inlet air temperature shall be selected as near to reference conditions (see 2) as possible in order to minimise the correction factor.
5.3.3 The temperature of the inlet air to the engine (ambient air), shall be measured within 0,15 m upstream of the air inlet duct work.
The thermometer or thermocouple shall be shielded from radiant heat and located directly in the airstream. It shall also be shielded from fuel spray back. A sufficient number of locations shall be used to give a representative average inlet temperature.
5.3.4 The inlet depression shall be measured downstream of the entry ducts, air filter, inlet silencer, speed-limiting device (if they are fitted) or their equivalents.
5.3.5 The absolute pressure at the entry to the engine, downstream of the compressor and heat exchanger, if they are fitted, shall be measured in the inlet manifold and at any other point where pressure has to be measured to calculate correction factors.
5.3.6 The exhaust back pressure shall be measured at a point at least three pipe diameters from the outlet flange(s) of the exhaust manifold(s) and downstream of the turbocharger(s), if fitted. The location shall be specified.
5.3.7 No data shall be taken until torque, speed and temperature have been maintained substantially constant for at least 1 mm.BS ISO 1585 pdf download.