Refueling System Overview

To effectively manage evaporative fuel emissions, hybrid vehicles with extended electrical range capability must be equipped with a "pressurized" fuel system that can be sealed from atmosphere when the internal combustion engine is not operating.

When the fuel system is sealed, the internal pressure will vary with changes in temperature, such as the natural variation in ambient temperature that occurs throughout the day. To maintain evaporative emissions compliance, vehicle refueling can only be permitted once the fuel system has been adequately vented to atmosphere through the carbon canister. The Refueling Management feature described in this document provides the necessary means to regulate customer access to the fuel cap and manage venting of the fuel system in order to facilitate vehicle refueling without compromising evaporative emissions compliance.