What kind of engine modification may be required for using CNG?

Using compressed natural gas (CNG) as a fuel for an engine typically requires adjustments to the fuel intake system to ensure that it properly accommodates gaseous fuel. Since CNG is a lighter gas compared to traditional liquid fuels, the fuel delivery system must be adapted to maintain the correct air-fuel mixture for efficient combustion. This includes modifications to the injectors and possibly the pressure regulators to ensure that the CNG can be effectively introduced into the combustion chamber.

While there could be circumstances where changing the entire fuel system or modifying the ignition system may seem necessary, the primary and most common requirement is typically adjustments to the existing fuel intake system, which allows for the existing engine components to better handle the unique properties of CNG. This approach helps in making the transition more efficient and cost-effective. Adjusting the fuel intake system is generally sufficient for many engines designed to run on liquid fuels, whereas altering the entire fuel system or other components can be more resource-intensive and may not be needed in many cases.