How does CNG Work

If you want to know how does the CNG conversion(s) work, please read on. You may know by now that you don’t need to buy a new CNG-powered car to start using clean and safe CNG and reduce your carbon footprint. Any vehicle running on gasoline and diesel can be converted to CNG. But do you know how CNG conversion is accomplished and how it works? Natural gas conversion may cost you a significant amount of money, so before you decide to go the CNG way, it is important that you know and understand how the installation of a CNG conversion kit in a gasoline-powered vehicle is done.

At the conversion center or shop, skilled technicians will install compressed natural gas (CNG components to your existing vehicle. These components make CNG the primary fuel for your vehicle with gasoline as the back-up fuel. A fuel selection switch will be installed (usually on the dashboard) that will allow the driver to manually select either CNG or gasoline. CNG storage cylinders will also be installed underneath the vehicle for vans and pickup trucks, or in the trunk for cabs and other cars. Stainless steel tubes and lines will transport the CNG to the regulator in the vehicle’s engine compartment to reduce the pressure. The CNG will then pass through a fuel-air mixer on its way to the intake manifold to be introduced for combustion.


Having a dual fuel system will ensure adequate fuel reserves in between natural gas fills. Compared to having only a gasoline engine, this additional fuel reserve will extend the vehicle’s driving range. Drivers can switch from CNG to gasoline even while driving, idling or parked. Some CNG systems will automatically switch to gasoline when the natural gas level reaches a preset low pressure setting.


For an inside look at how a CNG/gasoline bi-fuel system works, here are the step by step details:

  • CNG is fed into the high pressure cylinders through the natural gas receptacle
  • When the engine needs natural gas, CNG leaves the storage cylinders and passes through the master manual shut-off valve.
  • CNG enters the engine chamber via the stainless steel high pressure line.
  • The regulator accepts the CNG and reduces its pressure from 3,000 psi to approximate atmospheric pressure.
  • The natural gas solenoid valve lets the natural gas flow from the regulator into the gas mixer or fuel injectors. This same solenoid valve also shuts off the natural gas when the engine is stopped.
  • CNG mixes with air and flows down through the carburettor or fuel injection system and enters the engine’s combustion chambers.