The IntelliGas Technology History
In early 2007 the iGas technical team filed a
patent application for a CNG transfer system known as PLIGATS (Pressurised
Liquid Gas Transfer System). This system enabled the transfer of CNG
into a HPDI (High Pressure Direct Injection) engine at the pressure
required. The PLIGATS application maintains CNG delivery pressure to
the engine by the injection of hydraulic fluid into the cylinder as
the CNG is consumed.
The initial PLIGATS patent describes a CNG transfer method for PLIGATS equipped CNG storage cylinders wherein they are filled with liquid before re-fuelling. The liquid is then displaced from the cylinder whilst holding 350 barg back pressure on the out-flowing liquid. This process enables reliable fill to 100% of 350 barg nameplate capacity of the CNG storage cylinders, with up to 80% more energy in the cylinders than the present 200/250 barg conventional CNG filling systems.
The application of PLIGATS in a mobile application on the first two demonstration trucks enabled hundreds of hours of operation of the hydraulic transfer system, resulting in a number of improvements which have been incorporated in our fixed re-fuelling applications.
The PLIGATS system worked well over many thousands of kilometres on the prototype trucks, however it suffers from cost and complexity relative to conventional CNG systems. It is now being replaced for our mobile (on-truck) applications with the IntelliGas HDCNG™ Fuel Pack and IntelliGas Booster system which have been fitted to the Western Star HPDI demonstration trucks.