Doff Your (Gas) Cap

After more than 100 years, you wouldn't think the lowly gas cap would be a problem.

After more than 100 years, you wouldn't think the lowly gas cap would be a problem. However, it requires dexterity and hand strength to remove and replace the cap, something that is in short supply as the population ages and gas caps require more force to seal OBD2-compliant systems. "Studies show that an unsecured fuel cap results in a warranty cost of about $1 per car," says Eric Parker, v.p. Global Product Development at Illinois Tool Works (ITW, Glenview, IL;, "and this has caused some automakers to add a separate ‘check fuel cap' warning light to their cars." Why? Two reasons: (1) a loose cap allows hydrocarbons to escape into the atmosphere, and (2) vehicles have to take a 50 mph rear collision, be turned upside down, and not lose more than one ounce of fuel per minute. That can't be done if the cap is loose, or worse yet, missing.

ITW has an answer to this dilemma. It's called the Direct Fueling System (DFS), and replaces the gas cap with a ribbed shutter that pivots out of the way as it guides the nozzle into the receptacle. There the nozzle moves a flapper valve that seals the system out of the way. "The shutter keeps dirt from infiltrating the system," says Parker, adding that even a direct blast from a pressure washer didn't open the port and let contaminants into the system. The demonstration worked: Renault's Megane has a version of the system, as does the Ford GT.

Despite having to accommodate the 4-in. evaporative emission boot mandated for California gas stations, Parker claims the DFS unit can be "significantly smaller" than the 7-in. diameter fuel door commonly used today. And while he admits the design is slightly more expensive than conventional fuel filler systems, he claims the price will fall as volume increases and bring significant cost savings when the DFS is designed as part of the total fuel system. Nevertheless, Parker states that OEMs have shown a keen interest in DFS, and are looking to adopt it on some high-volume vehicle lines.—CAS