Patent Application
20110192477
Some vehicle fuel tanks may have partially separated regions within the fuel tank. For example, saddle and L-shaped fuel tanks having two deeper side regions separated by a shallower mid-interior region are commonly used in automotive applications. Saddle and L-shaped fuel tanks provide an external channel through which vehicle components, such as an exhaust conduit or a drive shaft, can pass. The external channel thus allows for a more compact vehicle design.
Some fuel delivery systems having saddle or L-shaped fuel tanks may extract fuel via a fuel pump from only one of the side regions of the fuel tank. Random vehicle motion may be relied upon to transfer fuel from the side region from which fuel is not extracted to another side region from which fuel is extracted. However, transferring fuel to the fuel pump in this manner may be somewhat unreliable and may decrease the amount of fuel that can be extracted from the fuel tank, thereby decreasing the range of the vehicle in which the fuel tank is utilized. This can be a particular issue in flex fuel vehicles when operating on ethanol blends, since these fuels may have lower energy densities, further reducing vehicle range.
Alternatively, other fuel delivery systems having saddle or L-shaped fuel tanks may use two fuel pump pick-ups or two separate fuel pumps located in both of the side regions of the fuel tank to extract the fuel from the fuel tank. However, this type of fuel delivery system can increase the cost and the complexity of the vehicle.
As such a system for a vehicle is provided. The system may include a fuel tank including a first and a second interior region at least partially separated from each other. The system may further include a fuel pump including a pick-up positioned in only the first region and a passive-siphoning subsystem with a crossover-siphoning conduit communicating between the first and second regions, the conduit enclosing a wicking element.
In this way, it is possible to passively transfer fuel from an isolated region to a fuel pump region and thereby better utilize stored fuel to extend the vehicle's range without using additional energy in the vehicle. The wicking element may also provide dampening within the fuel tank, thereby decreasing the noise, vibration, and harshness (NVH) during vehicle operation. Furthermore, the crossover-siphoning conduit may decrease rapid scattered movement of fuel (e.g., “splashing”) within the fuel tank which may degrade pump operation.
It should be understood that the background and summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
The following description relates to a system for a vehicle including a fuel tank having a first and a second interior region at least partially separated from each other, for example a saddle and L-shaped fuel tank having two deeper side regions separated by a shallower mid-interior region. The system may further include a fuel pump including a pick-up positioned in only the first region and a passive-siphoning subsystem with a crossover-siphoning conduit communicating between the first and second regions, the conduit enclosing a wicking element. The crossover-siphoning conduit may include an inlet positioned in the second region and an outlet positioned in the first region, where the conduit is configured to passively draw fuel from the second region to the first region. In this way, fuel resources contained within an isolated region of the fuel tank may be transferred to a region from which fuel can be extracted without using additional vehicle energy, thereby increasing the range of the vehicle.
The fuel delivery system may additionally include one or more fuel injector(s) 20 fluidly coupled to fuel pump 18 and configured to provide what is known as direct injection, port injection, or a combination thereof to internal combustion engine 14. It will be appreciated that the fuel delivery system may include additional components such as a fuel filter, a return-less fuel circuit, a fuel rail, a higher pressure pump coupled downstream of fuel pump 18, etc., in other embodiments.
The engine and fuel system may be configured to operate on gasoline and/or a gasoline/alcohol fuel blend, such as ethanol (e.g. E0 to E85). For example, the vehicle may include a controller with a computer readable storage medium having code to adjust fuel injection based on the fuel blend, such as the amount or percent of ethanol in the fuel.
The interior portion 201 of the fuel tank defined by housing 202 is shown including a first interior region 204, a second interior region 206, and a third interior region 208 separating, and positioned between, the first interior region from the second interior region. In this example, the first interior region is deeper than the second interior region, which is in turn deeper than the third interior region, thus creating a hump 203 below the third interior region, the third interior region completely separating the first and second regions.
Fuel pump 18 includes a pick-up 211. In the illustrated embodiment both the fuel pump and the pick-up are positioned in the first interior region, with the pick-up having an opening 212 for receiving fuel that is positioned below the depth of the second interior region. For example, the pick-up may be longer than d2. However in other embodiments the pick-up may be located in the first interior region and the fuel pump may be located outside fuel tank.
The fuel tank may further include a passive-siphoning subsystem 213 configured to passively draw fuel from the second interior region 206 to the first interior region 204 during certain operating conditions, such as when the level of fuel within the first interior region is less than the level of fuel within the second interior region. The passive-siphoning subsystem includes a crossover-siphoning conduit 214 communicating between the second interior region and the first interior region, thereby passing through the third interior region (with no openings to the third interior region). The crossover-siphoning conduit includes a conduit housing 216 enclosing a wicking element 218. An inlet 219 of the crossover-siphoning conduit is positioned in the second interior region 206 and an outlet 220 is positioned in the first interior region 204. The inlet may be positioned vertically above the outlet with respect to the bottom of the vehicle. For example, the inlet may have a greater vertical height h1 than the vertical height h2 of the outlet with respect to a bottom 221 of the vehicle, enabling passive siphoning, once flow begins. In this way, the wicking element may generate an initial flow, which is then increased and/or maintained by a siphoning effect.
In the illustrated embodiment, the wicking element may extend along the full length of the crossover-siphoning conduit and substantially span the width of the crossover-siphoning conduit. However, in other embodiments, the size and/or shape of the wicking element may be altered. For example, the wicking element may be included in only a portion of the crossover-siphoning conduit. For example, a first portion 222 of the crossover-siphoning conduit having a substantially vertical inclination may include the wicking element and a second portion, downstream of the first portion of the crossover-siphoning conduit, may not include the wicking element, where downstream in the aforementioned context refers to a direction oriented with the fluid travelling from the second interior region to the first interior region in the crossover-siphoning conduit.
The wicking element may be constructed of a porous material that draws fuel there through by capillary action. For example, the wicking element may be constructed out of polyethylene fiber, polypropylene fiber, ester fiber, stainless steel fiber, and/or another fuel compatible fiber. It will be appreciated that the intermolecular forces of the fuel in the wicking element may be greater than gravitational forces on the fuel fluid. In other words, fuel may travel up the first portion of the crossover-siphoning conduit via capillary action, thereby priming the crossover-siphoning conduit for subsequent siphoning action.
In some examples, the wicking element may be selected based on the type of fuel used in the vehicle. For example, a more porous wicking element may be used when a higher viscosity fuel, such as diesel, is used in the vehicle. However in other examples, additional or alternate fuel characteristics may be used to determine the type of wicking element employed with the passive-siphoning subsystem. Still further in other examples, a single type of wicking element may be used for a variety of fuel types.
After the crossover-siphoning conduit 214 has been primed via capillary action in the wicking element and when the level of the fuel within the second interior region is greater than the level of the fuel within the first interior region, siphoning of fuel from the second interior region to the first interior region occurs. In this way, siphoning action and capillary action may work in conjunction to draw fuel through the crossover-siphoning conduit into the first interior region. After the fuel is drawn into the first interior region, the fuel pump may better extract the fuel and deliver the fuel to the internal combustion engine. In this way, a greater amount of fuel resources within the fuel tank may be used by the engine, thereby extending the vehicle's range.
The wicking element in the passive-siphoning subsystem may also provide dampening within the fuel tank, thereby decreasing the noise, vibration, and harshness (NVH) in the fuel tank during vehicle operation. In this way, the stress and strain on component in the fuel tank from NVH may be decreased. Furthermore, the crossover-siphoning conduit may decrease rapid movement of fuel (e.g., “splashing”) within the fuel tank which may degrade pump operation. In other words, the crossover-siphoning conduit, in combination with the hump, may provide a resistive force to fuel moving rapidly within the fuel tank.
As noted above, the hump 203 may generate a void, or space, in which another vehicle component may be positioned. For example, an exhaust conduit or a drive-shaft may pass beneath the hump and below the third region.
Priming valve 302 may be arranged in at least two configurations; an open configuration and a closed configuration. In the open configuration fuel may be permitted to travel into the crossover-siphoning conduit through the priming valve. In this way, the wicking element may become at least partially saturated with fuel, priming the crossover-siphoning conduit for subsequent siphoning action. On the other hand, in the closed configuration, fuel may be substantially inhibited from traveling into the crossover-siphoning conduit through the priming valve. The priming valve may be in the open configuration when the fuel within the fuel tank is above a threshold level, such as when the fuel tank has been refilled. Likewise, the priming valve may be in the closed configuration when the fuel within the fuel tank is below the threshold level. In this way, fuel may be transferred into the crossover-siphoning conduit when the fuel in the fuel tank is above the threshold level. Furthermore, the fuel may be subsequently retained within the crossover-siphoning conduit when the fuel in the fuel tank drops below the threshold level.
The retention of fuel within the crossover-siphoning conduit may enable a rapid onset of siphoning action. Therefore, the time interval corresponding to the onset of the siphoning action in the passive-siphoning subsystem shown in
On the other hand
At 502 the method includes transferring fuel through a crossover-siphoning conduit via a priming valve coupled to the crossover-siphoning conduit when fuel contained within the fuel tank exceeds a threshold level. In this way, the priming valve may assist in priming the crossover-siphoning conduit. As previously discussed, the crossover-siphoning conduit may enclose a wicking element extending along at least a portion of the crossover-siphoning conduit. In some examples the wicking element may extend along the full length of the crossover-siphoning conduit. Further in some examples the priming valve may be coupled to a crest portion of the crossover-siphoning conduit, the crest portion may include a peak of the crossover-siphoning conduit, as previously discussed. Next at 504 the method includes substantially inhibiting fuel from entering into the crossover-siphoning conduit via the priming valve when fuel contained within the fuel tank is below the threshold level.
At 505 the method includes preventing gravity-driven flow from the second interior region to the first interior region when the vehicle is oriented on a level surface. At 506 the method includes passively drawing fuel from a second interior region of a fuel tank to a first interior region of the fuel tank isolated from the second interior region through the crossover-siphoning conduit. It will be appreciated that step 506 may be implemented when the level of fuel contained within the second interior region is greater than the level of fuel contained within the first interior region.
At 508 the method includes extracting fuel out of the fuel tank from only the first region via a fuel pump. The fuel pump may then provide fuel to downstream components. As previously discussed the downstream components may include a fuel rail, one or more fuel injectors, and an internal combustion engine.
The systems and methods described above allow fuel in a second interior region of a fuel tank to be passively transferred to a fuel pump and subsequently utilized by an internal combustion engine, thereby extending a vehicle's range without using additional energy. It will be appreciated that the aforementioned passive-siphoning subsystem may be inexpensive when compared to other systems that use mechanically or electrically driven pumps or other mechanical components to actively transfer fuel from a second interior region of a fuel tank to a first interior region of a fuel tank. Other benefits of the system include a reduction in NVH within the vehicle due to the dampening provided by the wicking element in the fuel tank. Furthermore, the crossover-siphoning conduit may decrease rapid scattered movement of fuel (e.g., “splashing”) within the fuel tank which may degrade with pump operation.
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
