Lesson 3 - Construction and operation of the CNG and LPG installations used to drive spark ignition engines [1]

First generation LPG installation.

The first generation LPG installation is used in cars with a carburettor power supply. The lack of an electronic controller makes it a cheap, but also the least precise and economical solution. It is the simplest installation that does not require almost any electronic controllers.

Principle of operation

In these systems LPG in the liquid phase IS passed from the gas tank through the multivalve to the evaporator reducer, where it goes from the liquid phase into the vapor phase and is ready to mix with the air. The gas is then supplied through a manual, constant regulator of the gas dose to the mixer. The air-gas mixture created in the mixer goes to the inlet manifold, and then through the suction valves to the cylinder. In the first generation systems, it is not possible to adjust the power supply to the current mode of operation of the engine, eg enriching the mixture during acceleration, shutting off the gas supply during braking.

Elements of the first generation LPG system layout:

·        gas inlet,

·        gas tank with accessories,

·        petrol-gas switch,

·        mixer,

·        gas solenoid,

·        reducer (evaporator).