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WSG-1068 FUEL SYSTEM
System Operation – Natural Gas
Natural gas passes through a vacuum operated fuel
shutoff valve into a regulator unit where it is converted
into a low pressure gas. This gas is then fed into the
mixer where a vacuum operated gas metering valve
ensures that the correct air-to-fuel ratio is maintained.
When the engine is switched off, vacuum supply to the
fuel shut-off vacuum is disconnected and the valve
closes, cutting off the fuel supply to the regulator.
Should the engine stall, the loss of vacuum will close the
fuel shut-off valve. When starting the engine, there is
sufficient vacuum present, even at cranking speed, to
open the fuel shut-off valve.
The system is similar to the LPG system, except a
convertor (vaporizer) is not used, and the coolan
connections are also not needed. A regulator is required
and must be supplied by the OEM to suit the mains gas
supply pressure.
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