control method of the fuel pump in a bi-fuel vehicle

The invention relates to a pump operation control method in essence an internal combustion engine in a vehicle bi-fuel, comprising a first motor supply system with gasoline, and a second system feeding liquefied petroleum gas (LPG) located upstream of said throttle valve, such that, in case of the engine with LPG, the electronic computer (11) controls gasoline engine power management of the engine fuel pump (12) intermittently and periodically, the duration of operation of said engine is determined to ensure setting the rail pressure (15) and the stop time of said motor being determined so that the pressure in the ramp not decrease below the residual pressure value.