Detection of leaks in a device for evaporating vapors of a fuel stored in a vehicle heat engine tank

A device (13) for evaporating vapors of a fuel stored in a motor vehicle tank (12), said vehicle comprising an engine (11) and a tank (12) for storing a fuel for burning in said engine (11), said evaporation device (13) comprising:

• an absorbent filter (131) suitable for filtering the vapors generated by the fuel stored in said tank (12),
• a so-called “absorption” circuit (132) connecting the absorbent filter (131) to the tank (12) so as to allow the gas vapors to be conveyed to the absorbent filter (131),
• a so-called “ventilation” circuit (135) connecting the outside of the vehicle to the absorbent filter (131) comprising an outlet valve (130) configured to switch between an open position in which the outlet valve allows the gases filtered by the absorbent filter (131) to escape to the outside, and a closed position in which the evaporation device (13) is isolated from the outside of the vehicle,
• a so-called “purge” circuit (133) connecting the absorbent filter (131) to the engine (11) of the vehicle and comprising an electric pump (136), suitable for allowing the fuel vapors absorbed by the absorbent filter (131) to flow to the engine (11), a pressure measurement sensor (137) and a purge valve (134) configured to switch between an open position, in which said purge valve allows the gases to flow from the absorbent filter (131) to the engine (11), and a closed position in which the absorbent filter (131) is isolated from the engine (11),
• said evaporation device (13) further comprising a bypass circuit (138) and a bypass valve (139) mounted between the absorption circuit (132), the purge circuit (133) and the tank (12), which is configured to move between a so-called “absorption” position, in which the bypass valve (139) allows the gases to flow between the tank (12) and the absorbent filter (131), via the absorption circuit (132), and a so-called “leak detection” position, in which the bypass valve (139) allows the gases to flow between the purge circuit (133) and the tank (12) via the bypass circuit (138), the electric pump (136) being configured to draw in gases from the outside to convey them, via the ventilation circuit (135), the absorbent filter (131) and the bypass circuit (138), to the tank (12), in order to pressurize said tank (12) and thus allow the detection of a leak in the evaporation device (13) by means of the pressure measurement sensor (137).