<p>A fuel vapor management system (18) for a powertrain (12) including an internal combustion engine (14), the system comprising a fuel tank (20) and a fuel evaporative canister (50) so that the fuel vapor (28) can transfer from the fuel tank (20) to the fuel evaporative canister (50). The system further comprises a separate container (42) to where part of the fuel vapor (28) contained in the fuel tank (20) can be transferred and stored in case of increasing pressure in the fuel tank (20) due to the ambient conditions, and from where the stored fuel vapor (28) can be returned to the fuel tank (20) in case of decreasing pressure in the fuel tank (20) due to the ambient conditions, so that under any ambient conditions the fuel tank (20) is maintained substantially at a predetermined level of pressure.</p>
