BAJA CALIFORNIA, Mexico—Morgan Polymer Seals wanted to make absolutely sure a specialized capless refueling sealing system was tried and tested—and then some—before doing a victory lap.
With more than two years of real-world service in place on the Cadillac CT6 sports sedan, the rubber company only now is lifting the curtain on the project undertaken in collaboration with Illinois Tool Works Inc. for General Motors Co.
Morgan and ITW worked together to create a "mechanical seal" that allowed the Cadillac to convert to a capless fueling system without a need for a major redesign.
Automobile makers see capless systems as a way to cut down on operator fueling errors. Cars with fuel caps, if they are not properly replaced after fueling, can throw codes that indicate problems with the vehicle.
The simple solution is to put the cap on properly, but vehicle owners often only find that out after taking their vehicles in for repair. Going capless eliminates that particular problem, but this approach has design challenges not associated with traditional fueling systems.
That's where Morgan Polymer Seals and ITW came in. They teamed up to create a solution that not only traps vapors but also allows for conversion to a capless system without the need for vehicle redesign, said Todd Tesky, vice president of sales at Morgan Polymer Seals.
As a sporty vehicle, the CT6 did not have the body design to allow for the installation of a larger fuel vapor canister, a typical and simpler move when going to capless systems. This canister serves to trap vapor that is introduced and then displaced during refueling before it can reach the environment.
Baja California-based Morgan Polymer Seals spent about nine months creating new design.
"The mechanical seal has two components. It has a double lip that seals on the fuel nozzle. And it has an overflow door seal," Tesky said. "During the refueling process, you push the fuel nozzle through that double lip seal and the rubber is actually creating a seal on the nozzle so that additional air cannot be introduced into the fuel stream, which creates hydrocarbons which must be dealt with in the evaporative emission system.
"The basic idea is when you are fueling up your car and you're introducing fuel you also are drawing air into the system, which needs to pass through the fuel vapor canister," he said.
Creating an air-tight seal around the nozzle created another challenge, requiring the design of "an over-flow door seal to be integrated within the constraints of the capless refueling assembly," the company said. Instead of fuel overwhelming the nozzle as can be the case with typical fueling systems, designers had to create an escape hatch that allowed fuel to overflow while still maintaining the integrity of the seal around the nozzle.
Morgan Polymer Seals only now is talking about the design breakthrough this summer, but the new approach actually has been working on vehicles for the past two to three years, company officials said.
"We're talking about automotive. You really don't want to spike the ball on a new product design until it's been out in the market and been tested and tried and true," Marketing Director Sam Morgan said.
Mark Conlee, engineering director for Morgan Polymer Seals, said the project presented some unique challenges his company was able to overcome.
"External constraints on the vapor canister necessitated a thin door to seal against the over-molded lip on the over-flow feature of the mechanical seal," he said in a statement. "This design created predictable but unwanted deflection of the plastic substrate from the spring force. To compensate for this deflection, we designed the seal lip to follow a 3D contour with varying height. By profiling the seal in this way, we assured the seal's integrity against the uniformly distributed sealing force."
The company has been able to produce the new seal with a scrap rate of less than 1 percent, Conlee said.
To learn more, visit www.MorganPolymerSeals.com.