Carbon Canister Development for Enhanced Evaporative Emissions and On-Board Refueling

Automotive fuel vapor emissions that would otherwise evaporate into the atmosphere are being captured in activated carbon vapor storage canisters. Fuel vapor is loaded into the canisters via a direct connection to the fuel tank vapor dome. Hydrocarbons are desorbed from the activated carbon into the engine combustion cylinders using engine intake vacuum.

The carbon canister capacity requirements have increased in recent years in order to meet both Enhanced Evaporative Emission regulations and the Clean Air Act emission requirements for On-board Refueling Vapor Recovery (ORVR). The higher capacity requirements have generated the need for larger volume canisters that can meet the emission requirements and still be designed within the space and packaging limits of the vehicle application.

This paper describes the simultaneous engineering approach used at Ford Motor Company to design a large volume cylindrical shaped carbon canister. A cross-functional team designed the canister from first conception to meet all structural integrity, packaging, manufacturing, capacity, and purge requirements. The development process, design parameter optimizations, analytical tools used, and the benefits of the finished product are discussed.