BACKGROUND AND SUMMARY

The present invention relates generally to fuel systems and, more particularly, to fuel systems including a lift pump and a high pressure pump.

In fuel systems for marine engines such as gasoline engines, it is desirable to keep any pressurized conduits as short as possible. U.S. Coast Guard regulation 33 C.F.R. 183.566 specifies that each fuel pump must be on the engine it serves or within 12 inches of the engine, unless it is a fuel pump used to transfer fuel between tanks. Thus, in many boats, where a fuel tank may be located a substantial distance from the engine, it is common to have a low pressure lift pump close to the engine to draw fuel from the tank at low pressure and into a reservoir from which it can be pumped by a high pressure pump to an engine or a fuel rail.

In typical fuel system designs, a low pressure lift pump delivers fuel from a fuel tank to a reservoir in which the high pressure pump is disposed. In some fuel system designs, the high pressure pump and a fuel level sensor are disposed in the reservoir and immersed in fuel, while the low pressure pump is disposed outside of the reservoir. In other fuel system designs, the fuel level sensor is in a reservoir, while the high pressure pump and the low pressure pump are outside of the reservoir. In still other fuel system designs, the high pressure pump, the fuel level sensor, and the low pressure pump are all disposed in the reservoir and immersed in fuel.

Cooling of the components in the reservoir is achieved by cooling the exterior of the reservoir, usually by exposure to air, which can be quite inefficient. Components outside of the reservoir, such as a lift pump, may be more easily cooled by exposure to air than components inside the reservoir, however, they can be noisy. During operation, heat generating components such as the pumps can raise the temperature of the fuel and increase the amount of vapor in the reservoir. Additionally, high pressure pumps for most fuel systems for watercraft pump substantially more fuel than is required by the engine at idle and the excess fuel is typically returned to the reservoir at high pressure and increased temperature, which tends to generate vapor. It is, therefore, important to provide a fuel system that can efficiently cool the fuel and components in the fuel system.

In accordance with an aspect of the present invention, a fuel module comprises a jacket having a wall defining a jacket interior space, a low pressure pump container in the jacket interior space, a vapor chamber container in the jacket interior space, and a high pressure pump container in the jacket interior space.

By the present invention, it is possible to provide substantially more surface area for cooling of components of the fuel module as cooling water can be caused to flow directly over the individual containers. Additionally, having pumps inside the jacket can facilitate providing a much quieter fuel system than a system in which a pump is outside of a reservoir. Further, separating a vapor control system from the high pressure pump allows for better separation of vapor and liquid.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present invention are well understood by reading the following detailed description in conjunction with the drawings in which like numerals indicate similar elements and in which:

FIG. 1 is a schematic view of a fuel module according to an aspect of the present invention;

FIGS. 2A-2F are front, top, bottom, right side, left side and rear views of a fuel module according to an aspect of the present invention;

FIGS. 3A and 3B are cross-sectional views the fuel module of FIGS. 2A-2F taken at section 3A-3A and 3B-3B of FIG. 2B;

FIG.4 is a perspective view of a bottom side of a top cap according to an aspect of the present invention;

FIG. 5 is a perspective view of a top side of a bottom cap according to an aspect of the present invention; and

FIG. 6 is a cross-sectional view of the fuel module of FIGS. 2A-2F taken at section 6A- 6B of FIG. 2B.

DETAILED DESCRIPTION

A fuel module 21 according to an aspect of the present invention is schematically shown in FIG. 1. The fuel module 21 includes a jacket 23 having a wall defining a jacket interior space 27, a low pressure pump container 29 in the jacket interior space, a vapor chamber container 31 in the jacket interior space, and a high pressure pump container 33 in the jacket interior space. The low pressure pump container 29 includes a low pressure pump container interior space 35, a first pump 37, a low pressure pump container inlet opening 39, and a low pressure pump container outlet opening 41. The vapor chamber container 31 includes a vapor chamber container interior space 43, a fuel level sensor 45 (typically a float) configured to sense a fuel level in the vapor chamber container interior space, a vapor chamber container inlet opening 47 in fluid communication with the low pressure pump container outlet opening 41, and a vapor chamber container outlet opening 49. The high pressure pump container 33 includes a high pressure pump container interior space 51 , a second pump 53, a high pressure pump container inlet opening 55 in fluid communication with the vapor chamber container outlet opening 49, and a high pressure pump container outlet opening 57.

An embodiment of the fuel module 21 is shown in FIGS. 2A-2F. As seen in FIG. 3A-3B, the jacket 23 comprises a main body portion 59 having a wall 25 that defines part of the jacket interior space 27 and a top cap 61 that defines a further part of the jacket interior space. A bottom cap 63 is disposed in the jacket interior space 27. The top cap 61 and the bottom cap 63 can form parts of the low pressure pump container 29, the vapor chamber container 31„ and the high pressure pump container 33.

As seen in FIG. 4, the top cap 61 can include an inner surface 65 from which three cylindrical rings project to form three top cap cups 67, 69, and 71 and that form parts of the low pressure pump container 29, the vapor chamber container 31 , and the high pressure pump container 33, respectively. As seen in FIG. 5, the bottom cap 63 can include three cylindrical bottom cap cups 73, 75, and 77 that can be connected by a web 79 and that form parts of the low pressure pump container 29, the vapor chamber container 31 , and the high pressure pump container 33, respectively.

As seen in FIG. 3 A, the vapor chamber container 31 is formed by the top cap cup 69, the bottom cap cup 75, and a cylinder 81 that is secured in the top cap cup and the bottom cap cup, such as by O-ring seals 83, and that together define the vapor chamber container interior space 43. The fuel level sensor 45, which is preferably in the form of a float and, more particularly, a decoupled float that is axially movable in the cylinder 81 in response to a level of fuel in the vapor chamber container 31, is provided inside the vapor chamber container. The fuel level sensor/decoupled float 45 is configured, such as by a mechanical linkage, to close a venting valve 133 (FIG. 1) in a venting conduit 135 between the vapor chamber container 31 and an intake of the engine 113 when the level of liquid in the vapor chamber 31 reaches a first predetermined height and to open the venting valve when the liquid level falls to a second predetermined height (which is typically lower than the first predetermined height but may be the same height as the first predetermined height). The decoupled float 45 can be linked to the venting valve by a needle 137 (shown schematically in phantom) that seats in an opening of the venting valve 133 to close the venting valve and is unseated to open the venting valve. The needle 137 can be spring loaded by a spring 89 or other suitable structure to keep the venting valve 133 closed until the decoupled float 45 falls to the second predetermined height. In this way, inadvertent opening and closing of the venting valve 133 that might occur due to vibration such as when a vessel bounces over waves can be minimized.

As seen in FIG. 3B, the low pressure pump container 29 is formed by the top cap cup 67, the bottom cap cup 73, and a cylinder 91 that is secured in the top cap cup and the bottom cap cup, such as by O-ring seals 83. The first pump 37, also referred to as the low pressure pump, is ordinarily a positive displacement pump such as a roller cell pump or a gerotor pump that is secured in the bottom cap cup 73 so that a chamber 35a forming part of the low pressure pump container interior space 35 is formed between the first pump and the bottom cap cup. The first pump 37 creates a suction in the chamber between the first pump 37 and the bottom cap cup 73 so that fuel is drawn through the low pressure pump container inlet opening 39 in the bottom cap cup from a conduit 93 (FIG. 1) that connects the chamber between the first pump and the bottom cap cup to a fuel filter 95 which, in turn, as shown in FIG. 1, is connected by a conduit 97 to a fuel tank 99. The first pump 37 is typically sealed to the bottom cap cup 73. By enclosing the first pump 37 (and the second pump 53) within the jacket 23, noise from operation of the fuel module 21 can be kept to a minimum. The seals 83 supporting the pumps 37 and 53 can further facilitate isolating vibration and reducing noise.

A valve 87 (FIG. 1) is provided in a conduit 101 between the vapor chamber container 31 and the low pressure pump container 29. The valve 87 is ordinarily one way check valve (similar to a one way check valve 105 ordinarily provided between the low pressure pump container 29 and a fuel filter 95, but with lower opening pressure) that allows liquid and vapor flow from the low pressure pump container to the vapor chamber container 31 but blocks any backward flow from vapor chamber container 31 to the low pressure pump container 29. With this valve 87, the low pressure pump chamber container 29 (and the fuel filter 95) can be isolated from the high vapor pressure of the vapor chamber container 31 in the event of vaporization of fuel in the vapor chamber container.

As seen in FIG. 1 , a further chamber 35b forming part of the low pressure pump container interior space 35 is formed between the top of the first pump 37 and the top cap cup 67. The conduit 101 connects the chamber formed between the top of the first pump 37 and the top cap cup 67 and the vapor chamber container 31. The conduit 101 or parts thereof can be integrally formed in the top cap 61 as one or more molded or machined parts. Other conduits or parts thereof can be integrally formed in the top cap 61 as one or more molded or machined parts. The valve 87 is typically configured to open or close the conduit 101 depending upon whether the float 45 is below or above the predetermined height, respectively.

Another conduit 103 connects the chamber formed between the top of the first pump 37 and the top cap cup 67 and the fuel filter 95. A check valve 105 is provided in the conduit 103 and is arranged to crack when pressure in the chamber formed between the top of the first pump 37 and the top cap cup 67 exceeds a predetermined level, such as may occur when the valve 87 closes while the first pump 37 continues to pump. This feature, in addition to avoiding excessive pressure in the system, facilitates providing extra filtering of the fuel in the fuel module 21. The conduit 103 can be integrally formed in the top cap 61 as one or more molded or machined parts.

As seen in FIG. 3B, the high pressure pump container 33 is formed by the top cap cup 71, the bottom cap cup 77, and a cylinder 107 that is secured in the top cap cup and the bottom cap cup, such as by O-ring seals 83. The second pump 53 is preferably a turbine pump and is spaced from walls of the high pressure pump container interior space 51 by fins 85 or other suitable structures. As seen in, e.g., FIG. 1 ,an outlet 109 of the second pump 53 is connected to the high pressure pump container outlet opening 57 which, in turn connects to a conduit 111 leading to a fuel rail of an engine 113 (or the outlet of the second pump is connected directly to the conduit to the engine). The second pump 53 is preferably a turbine pump. Such pumps typically must be partially or fully submerged in fluid to operate, however, they are typically less noisy than positive displacement pumps. The vapor chamber container outlet opening 49 is in a bottom half of the vapor chamber container 31 and the high pressure pump container inlet opening 55 is in a bottom half of the high pressure pump container 33. Typically, the high pressure pump container inlet opening 55 is disposed at a bottom of the high pressure pump container interior space 51 and is in fluid communication with the vapor chamber container outlet opening 49 at the bottom of the vapor chamber container interior space 43 via a conduit 115 that can be integrally formed in the bottom cap 63.

As seen in FIG. 1 , the vapor chamber container 31 comprises an opening in a top half of the vapor chamber container 31 in fluid communication with an opening in a top half of the high pressure pump container 33. A conduit 117 connects the opening at top end of the high pressure pump container 33 with the opening at the top end of the vapor chamber container 31 and facilitates equalization of vapor pressure between the high pressure pump container 33 and the vapor chamber container 31. The conduit 117 can be integrally formed in the top cap 61 as one or more molded or machined parts.

A regulator 119 is mounted on the outlet side of the high-pressure pump 53 to ensure that the fuel rail receives fuel at a desired pressure. This regulator 119 allows fuel in excess of demand by the engine 113 to bypass back into the vapor chamber container 31 via a conduit connected to a return opening in the top of the vapor chamber container. The separation of the vapor chamber container 31 and high pressure pump container 33 allows high-velocity returning fuel to settle before being picked up by the second (high pressure) pump 53. This is important because, at idle condition, the amount of fuel that bypasses back into the vapor chamber container 31 can be more than 95% of the fuel pump capacity, and this fuel is ordinarily recirculated at a very high velocity. This high velocity fuel has a propensity to turn into vapor due to its high energy content. Because the fuel is returned to the vapor chamber container 31 , and the vapor chamber container 31 only communicates with the high-pressure pump chamber via two conduits 1 IS and 117, the fuel has ample time to separate into liquid and vapor, thereby preventing the high-pressure pump 53 from pulling vapor and cavitating.

The jacket 23 has an inlet opening 121 to the jacket interior space 27, usually in a bottom of the main body portion 59, and an outlet opening 123 to the jacket interior space, usually in the top cap 61. The inlet opening 121 is typically connected to a source of cooling fluid, such as water from the body of water in which the vessel is disposed, and the outlet opening 123 is typically returned to the source of cooling fluid. A pump 125 can be provided and connected to the inlet opening 121 to pump cooling fluid into the jacket interior space 27.

The low pressure pump container 29, the vapor chamber container 31 , and the high pressure pump container 33 can be arranged to define a triangle when viewed from above. The inlet opening 121 will ordinarily be disposed closer to a center of such a triangle than to any corner of the triangle to equally distribute cooling fluid about the containers and tends to force cooling fluid to make contact with significant portions of each of the containers before exiting the jacket interior space 27.

At least portions of side walls of the low pressure pump container 29, the vapor chamber container 31, and the high pressure pump container 33 between top and bottom ends of the low pressure pump container, the vapor chamber container, and the high pressure pump container are exposed to the jacket interior space 27 so that they can be in direct contact with cooling fluid in the jacket interior space, and at least these portions are ordinarily exposed to the jacket interior space around entire peripheries of the side walls of the low pressure pump container, the vapor chamber container, and the high pressure pump container so that these portions are in direct contact with cooling fluid in the jacket interior space. The bottom ends of the low pressure pump container 29, the vapor chamber container 31 , and the high pressure pump container 33 are typically also exposed to the jacket interior space 27 by virtue of the bottom cap 63 being spaced slightly from the interior of the wall 25 of the main body portion 59 of the jacket 23 so that they can be in direct contact with cooling fluid in the jacket interior space. By this arrangement, a substantial increase in surface area of pump components for cooling can be provided relative to pump modules that are only cooled by coolant on an exterior surface of the entire module. In addition, cooling fluid can be applied to surfaces closer to the sources of heat generation, such as the first and second pumps 37 and 53, than in pump modules wherein low and high pressure pumps are disposed inside of a jacket and remote from walls of the jacket. By maximizing the cooling of the components of the fuel module by facilitating greater heat exchange between heat generating components than in modules where all or some heat generating components are submerged in fuel inside of a jacket and remote from cooling fluid, the generation of vapor can be minimized and the condensation of vapor can be maximized, thereby reducing the opportunity for vapor lock.

The fuel filter 95 is mounted to the jacket 23, typically outside of the jacket interior space 27, typically secured to the top cap 61. An outlet 127 (FIG. 1 ) of the fuel filter 95 can be connected to a conduit 93 that, as seen in FIG. 6, can include a hose that connects to the low pressure pump container inlet opening 39. As seen in, e.g., FIG. 2 A, the jacket 23 can be provided with mounting brackets 129 for mounting to a vessel. Electrical connections 131 can be provided through the top cap 61 for the first and second pumps 37 and 53.

An exterior of the jacket 23 can be provided with fins to further facilitate cooling and minimize the possibility of damage due to fire. Further, because the fuel module 21 is cooled by water flowing through the jacket 23, components of the fuel module such as the main body portion 59 of the jacket, the top cap 61 of the jacket, the bottom cap 63, and the cylinders 81, 91, and 107 can be made out of molded plastic and still pass lire tests because the jacket will absorb heat. The cylinders the cylinders 81, 91, and 107 will, however, typically made of a material that acilitates heat transfer, such as stainless steel. Such a fuel module 21 can be substantially lighter and less expensive to manufacture than a fuel module with machined metal parts.

In the present application, the use of terms such as "including" is open-ended and is intended to have the same meaning as terms such as "comprising" and not preclude the presence of other structure, material, or acts. Similarly, though the use of terms such as "can" or "may" is intended to be open-ended and to reflect that structure, material, or acts are not necessary, the failure to use such terms is not intended to reflect that structure, material, or acts are essential. To the extent that structure, material, or acts are presently considered to be essential, they are identified as such.

While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.