The engine management technology can be applied to both naturally aspirated and turbocharged diesel engines. Dual fuel engines normally operate on a mixture of diesel and gas but can revert to diesel only operation if required. Dual fuel conversions require few mechanical changes to the engine. Dedicated gas engines require major changes to the cylinder head and pistons of the engine but require only one fuel.
Dedicated engines are capable of very low exhaust emissions.
The most common conversion to CNG or LPG undertaken on petrol engines is a BI-fuel conversion. This requires few mechanical changes and allows the engine to operate on CNG or petrol. Dedicated gas engine conversions from petrol requires the compression ratio to be increased and a gas carburettor or gas injection system to be installed. The higher compression ratio may also require a higher output ignition system. An engine management system may be used in some applications.