P4 & P6 Converter
with Fixed Venturi Mixer
Ford ED 4.0 lt. Sedan

HOW THE LPG SYSTEM WORKS?

A typical L.P.G. system consists of the following parts.

Initially there is the tank which contains L.P.G. under very high pressure.

L.P.G. flows through a filter/lock-off valve, a valve that only opens when there is an engine rpm signal sensed. The function of a lock-off is for safety so that L.P.G. cannot flow from the tank when the engine is off.

B2 Converter
Variable Mixer
Ford F150 5.8lt. pick-up

The L.P.G. changes from a liquid to a gas in the vapouriser/regulator. They are classified as "simple" or "complex. A simple vapouriser/regulator does not require any external adjustment and all it does is change the state of the L.P.G. (Aussie B2). On the other hand a complex vapouriser/regulator has adjustment screws for changing idle mixtures. (Aussie P4 & P6).

Once the L.P.G has gone through the converter it is in a gaseous form, thus it can be added to the intake system of the engine. The addition of the L.P.G. must be in the right proportions to the mass of air being breathed, otherwise the air/fuel ratio will not be optimal for the operating conditions of the engine.

The device adding the L.P.G. to the intake air is called a Mixer. Mixers varely in complexity, depending on what vapouriser/regulator is being used. The simple mixer is an aluminium ring, and it comprises just a venturi (flow restrictor) and a gas pipe connection. The pressure drop casued by the venturi encourages the gas to flow through the tube. This simple mixer needs to be used in conjunction with a complex converter, so that the correct adjustment of the air/fuel ratio can occur.

More complex mixers can be used with a simple converter because the mixer itself provides the adjustment of the mixtures.

If the vehicle is post 1986 (ie built to run on unleaded petrol) it must be fitted with an L.P.G. Fuel Control Processor.

12. in-line fuse
13. Braided vapour
       hose

12. in-line fuse
13. Braided vapour
       hose