This invention relates to fuel delivery components for use with water-cooled internal combustion engines in a marine environment, and more specifically to a water-cooled fuel pump, fuel filter, and fuel-pressure regulator assembly.
Generally, internal combustion engine propulsion systems adapted for marine use are water-cooled, and external engine components are housed within sealed enclosures to prevent moisture damage. Typically during operation, these components generate excess heat which may damage the components if not dissipated, a condition which is exacerbated by the sealed enclosures within which the components are housed. The need to reduce the volume of space on a marine craft occupied by the engine and its associated components has led to the development of multi-functional engine components which combine several individual components into a single sealed enclosure or housing. However, as engine components are grouped together, other problems may arise, for example, in fuel system components, the problems of excess heat dissipation and vapor lock must be addressed.
Several dual component combinations for use with internal combustion engine fuel systems are shown in the prior art. For example, U.S. Pat. No. 3,835,822, to Mickle et al., discloses directing a cooling water supply around a heat sink and fuel pump enclosed within a sealed housing, thereby cooling fuel pump and the fuel flowing within. By cooling the fuel pump and the fuel, the risk of vapor lock conditions in the fuel lines caused by excessive heat is reduced. However, as shown in the '822 patent, the heat sink abuts only the outer surface of the fuel pump, and is not configured to optimally cool the fuel itself.
Similarly, U.S. Pat. No. 5,231,967, to Baltz et al., discloses mounting a fuel pump and coaxially aligned fuel filter directly to an engine block by use of a housing. The fuel pump is located downstream from the fuel filter in the fuel system, and the filter is mounted such that the configuration simplifies maintenance and shields the underside of the fuel pump from fire. While this configuration is useful in minimizing space occupied in the engine compartment by the fuel filter and fuel pump, the proximity of the units to the engine block can lead to problem with dissipation of excess heat generated by the fuel pump, and the absorption of heat directly from the engine block.
U.S. Pat. No. 5,647,331, to Swanson discloses a device in which a liquid-cooled fuel pump incorporates a vapor separator module to reduce vapor lock created by both the absorption of excess heat in the fuel, and the vibration associated with the operation of marine internal combustion engines. The '331 device directs a liquid coolant over a casing comprising modular cavities, one cavity being a fuel reservoir and another cavity housing the fuel pump. The fuel reservoir is bathed by the coolant prior to fuel entering the pump, thereby reducing the intake temperature of the fuel. The device disclosed in the '331 patent is remotely located from both the tank and the engine and hence requires additional enclosures within the boat hull, and additional fuel lines. This to the complexity of the boat, both in building and servicing,
Accordingly, in the attempt to reduce the amount of space occupied by components of marine propulsion systems, and in particular, internal combustion engines, there is need for a combination fuel pump, fuel filter, and fuel regulator capable dissipating excess heat to reduce the occurrence of fuel system vapor lock.