Latching Refueling Valve with Low Friction Materials Saves Energy

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Engineers at system supplier Continental Automotive knew the use of high-performance, low friction materials would be a key to success for the new latching refueling valve (L-RV) they were developing for Ford Motor Company hybrid electric vehicles (HEVs). DuPont™ Zytel® and Zytel® HTN proved to be ideal choices.

Application Description

First bi-stable L-RV that eliminates power draw in both the open and closed state. It was developed by Continental Automotive, a leading system supplier known for providing innovative, sustainable, safe and affordable solutions that contribute to enhanced driving safety and global climate protection.

Used in Ford Fusion and Lincoln MKZ HEVs, this unique bi-stable L-RV, which is made with low friction materials, was a finalist in the Society of Plastics Engineers (SPE) Automotive Innovation Awards competition in the chassis/hardware category in 2016.

Unmet Need 

HEVs use both internal combustion engines and battery power. The efficient use of electric power to optimize fuel economy and minimize greenhouse gas emissions is critical. Therefore, maximizing range and performance of HEVs by minimizing power draw from ancillary functions and processes is an ongoing priority.

Challenges 

  • The operating environment of the valve system includes fuel exposure at temperatures exceeding 100°C.
  • Stable and consistent frictional forces are required to ensure free movement of valve components over a wide range of temperatures and fuel exposure conditions.

Solution

After conducting extensive prototype testing of various materials in collaboration with Ford Motor Company Fuel Test Labs, the engineers found that of all the low friction materials tested, DuPont™ Zytel® HTN consistently maintained required material properties after prolonged exposure to fuel conditions, making it ideal for the latch component of this application. In addition, Zytel® was selected for the housing structure due to its laser welding capability for the hermetic system seal.

The patented Continental design uses an internal latch mechanism with a single activation pulse. This L-RV, which stays open with no energy during refueling:

  • Increases battery life through a 150,000% reduction in energy usage compared to existing valve designs.
  • Meets emission standards during fuel fill events by directing fuel vapor through the carbon canister to trap hydrocarbons so they do not enter the atmosphere.
  • Features a simple design that is easily extendable to replace conventional solenoid valves in a variety of applications.
DuPont Materials Chosen and Why

DuPont™ Zytel® HTN was chosen for the latch component of this application because it offers:

  • Low coefficient of friction over the wide range of temperatures and fuel conditions that this component will be exposed to during its service life
  • Enhanced wear protection for increased durability
  • Dimensional stability, even after prolonged exposure to fuel
  • Excellent processing capabilities to enable tight tolerance micro features

DuPont™ Zytel® was chosen for the housing structure of this application because it provides:

  • Flexibility for advanced manufacturing technologies
  • Laser welding capability for the hermetic system seal

PART OF THE 2016 SPE AUTOMOTIVE INNOVATION AWARDS PROGRAM

CHASSIS / HARDWARE CATEGORY