This type of system is indicated for the transformation of vehicles with caruration  carburetor or injection engine approved up to EURO 2.
The LPG in the liquid state is placed in the tank and from here taken through a  multi-valve, and along the high pressure line reaches the reducer/vaporizer through a solenoid valve which is only open when the engine is running.
In the regulator the liquid LPG reduces its pressure and passes to the gaseous state by utilizing the heat required for the change of state from engine cooling water.
The LPG in the gaseous state then reaches the mixer that has the function of determining the gas flow in proportion to the engine requirement represented by the   vacuum that is generated, by Venturi effect, in the mixer itself.
In the case of injection engines (EURO 1 and EURO 2) will also need to install an electronic control unit (DL401) which controls a motorized register place between the regulator and the mixer, it adjust accurately the gas using the signal of the oxygen sensor.