Abstract
In current vehicles it is requested to have an intelligence diagnostic on board, which recognises if any emission relevant component or system has some failure. In a bifuel (gasoline and LPG) application, the On Board Diagnostic (OBD) needs to observe both gasoline and LPG errors. Gasoline engine management controls have studied many strategies to check errors and all these strategies are integrated into the gasoline electronic control unit. Adding LPG management in an originally gasoline vehicle, it is not convenient to modify the existing diagnostic system because it has been designed and tested in a configuration already defined and strictly linked to the engine as provided by the engine manufacturer. So the specific gas diagnostic has been integrated to collect further information from the gasoline diagnostic to provide the user a complete set of knowledge that, without understanding the dual structure, allows to find the broken component and set-up the vehicle with the original pollution levels. So the bifuel vehicle, designed to have a very low emission level, will keep under control the pollution even with some parts broken.