ISO 15500-6-2020 pdf download.Road vehicles一Compressed natural gas (CNG) fuel system components一 Part 6: Automatic valve.
6.4.3 If the automatic valve is to be used in vehicles with start-stop systems, and closed during commanded stop phases, the valve shall be submitted to the following numbers of operations during testing:
a) 200 000 cycles (mark NHV) if the engine shuts off automatically when the vehicle comes to a halt;
b) 500 000 cycles (mark “H2) if, in addition to a), the engine also shuts off automatically when the vehicle drives with the electric motor only;
c) 1 000 000 cycles (mark “H3) if, in addition to a) or b), the engine also shuts off automatically when the accelerator pedal is released.
6.5 Insulation resistance
The insulation resistance test is designed to check for a potential failure of the insulation between the two-pin coil assembly and the automatic valve casing.
If the automatic valve is electrically operated and is to be used inside a gas-tight housing, it shall be intrinsically safe as defined in IEC 60079-10-1.
Apply DC 1 000 V between one of the connector pins and the housing of the automatic valve for at least 2 s. The minimum allowable resistance shall be 240 kil.
6.6 Minimum opening voltage
The minimum opening voltage at room temperature shall be 8 V for a 12 V system and <16 V for a 24 V system. The component shall be pressurized at 0.75 times the working pressure during the test.
For systems with other nominal voltages the test shall be made at <66 % of the system’s nominal voltage.
6.7 Pressure impulse
The automatic valve that is exposed in service to cylinder pressure, shall withstand 100 pressure pulses, as follows.
a) If the automatic valve is external, connect both inlet and outlet to a pipe or tube of the type specified by the manufacturer and of at least 1 m in length each.
b) If the automatic valve is mounted to or inside the cylinder valve, the cylinder valve containing the automatic valve shall be connected securely by a suitable fitting to a pressurized source of dry air, nitrogen or natural gas. Connect the outlet to a pipe or tube of the type specified by the manufacturer and of at least 1 m in length each.
c) The outlet of the automatic valve shall be vented until the inlet is at atmospheric pressure, and then the outlet of the valve shall be closed.
d) Working pressure shall be instantaneously applied to the inlet.
e) Test the component in the same way with reverse flow direction.
Following the pressure impulse test, the automatic valve should operate according to the manufacturer’s specification.ISO 15500-6 pdf download.