Overfill Prevention System
With EPA evaporative emissions compliance dates nearing, there has been an interest in refueling systems not seen before in the marine industry. Boat builders will need to make a decision in the near future as to how they will comply with the pending diurnal and refueling regulations.
Understanding the benefits of Enviro-Fill’s OPS will make that decision easier. Our OPS consists of two components that work together to achieve the requirements of the pending evaporative emissions regulations.
Deck Fill Fitting
The deck fitting mounts as a standard deck fill currently mounts. Designs are being reviewed to fit the demands of boat builders. Straight and 30 degree flanges in plastic and S/S are being considered.
Tank Sensor/Vent Fitting
The tank sensor/vent fitting is mounted to the fuel tank with a standard SAE fuel sending unit bolt pattern. This has proven to be a reliable penetration into both plastic and aluminum tanks. Nearly all tanks use this pattern for fuel level sending units so tank manufacturers are familiar with this installation.
The diurnal emissions control is an integral part of the deck fitting. Venting is through the deck fitting during refueling – this eliminates the problem of premature shutoffs due to dirty/saturated carbon canisters causing higher tank pressures during refueling.
When the cap is closed after refueling, the tank is vented through a patent pending valve system that meets the diurnal requirements using a 1 psi pressure relief system. If a carbon canister based diurnal system is chosen, the deck fill is supplied with the required vent valve.
Enviro-Fill will be design certifying that both systems will provide auto shutoff at a point that allows for ullage in the tank and prevent liquid fuel from entering the carbon canister if that method is chosen.
Auto shutoff without spilling or spitback has been demonstrated by testing our system on ABYC’s test boat. Fill tests were conducted by Testing Services Group in Lapeer, Mich., and consisted of fills at 8, 10, 14 and18 gpm. These fills were repeated at level and 4 degrees of heel forward, aft, port and starboard. The fills were consistent at all the fill rates with no premature shutoffs. It should be pointed out that without our system the boat inherently had problems refueling.
The tank sensor/vent fitting is placed at a location in the tank that will allow venting at ABYC’s required angle of heel. Because we don’t use a check valve in the fill hose, we use it as a vent hose instead of installing extra grade vents.
