Reduced engine operation times in plug-in hybrid electric vehicles (PHEVs) enable fuel economy and reduced fuel emissions benefits. However, the shorter engine operation times can lead to longer refueling intervals ultimately resulting in fuel in a fuel tank of the vehicle becoming old, or sour. Fuel souring may cause acid formation and/or waxing, for example.
One approach to address potential souring of on-board fuel is to force engine on operation to a greater extent, even if not needed. However, the inventors herein have recognized a problem with such an approach. Namely, user satisfaction with the plug-in vehicle may become degraded because the user may be aiming to minimize addition of fuel, and forcing engine operation to utilize stale fuel is directly contrary to the user's goal.
Thus, the inventors herein have devised an approach to at least partially address the issue described above. In one example, a method for a vehicle including an engine and a motor includes displaying a recommended engine fuel fill amount based on a history of actual fuel usage. As an example, the recommended engine fuel fill amount may be determined based on an amount of fuel consumed over a duration, such as since a last fuel refill.
In this way, forced engine operation may be reduced such that user satisfaction may be improved. For example, by determining the amount of fuel consumed since the last fuel refill, an operator of the vehicle may be informed of his/her fuel usage via a display in the vehicle. As such, when the operator refills a fuel tank of the vehicle, the operator may refill the fuel tank with just enough fuel for a selected duration (e.g., three months) such that fuel souring may be prevented. Further, as the operator follows the recommended fuel fill amount, a frequency of forced engine operation (e.g., a fuel maintenance mode) may be reduced, as there is no longer excess fuel that needs to be consumed before souring can occur.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.