Patent Application
20140117118
This specification relates to detecting leaks in a feedthrough device, for example, in a fuel injector system. Electro-mechanical fuel injectors are controlled by electrical signals carried by conductors that extend from a low pressure environment into a high pressure zone. The high pressure zone contains a combustible fuel mixture. To prevent the combustible fuel mixture from leaking to the environment, a feedthrough provides a seal around the conductors at the interface where the conductors enter the high pressure zone.
Some conventional feedthroughs include groups of soldered, crimped, or otherwise connected wire strands, with each group of wire strands contained within a solid conductor that is sealed on its outer diameter. A nonconductive body around the conductors seals the conductors relative to each other and ensures insulative spacing between the conductors. When the feedthrough is installed in a fuel injector system, an O-ring seals around the nonconductive body of the feedthrough.
In one general aspect, a feedthrough device includes an internal leak-detection zone. In some instances, the feedthrough device can be included in a fuel injector system.
In some aspects, a feedthrough device includes first and second opposing outer end faces. The feedthrough device includes an opening, between the first and second opposing outer end faces, that allows fluid communication between an interior and an exterior of the feedthrough device. A conductor extends through the feedthrough device from the first end face, through the interior, to the second end face.
In some aspects, the feedthrough device is adapted for installation between a high pressure zone and a low pressure zone of a fuel injector system. The feedthrough device includes a feedthrough body. The feedthrough body includes a first outer end face and a second outer end face opposite the first outer end face. The feedthrough body includes an outer surface between the first outer end face and the second outer end face. The feedthrough body includes an interior surface defining a cavity. The cavity is disposed between the first outer end face and the second outer end face. The feedthrough body includes a fluid passage through the outer surface that allows fluid communication between the cavity and an exterior of the feedthrough body. The feedthrough device includes a conductor extending through the feedthrough body from the first end face, through the cavity, to the second end face.
Implementations may include one or more of the following features. The feedthrough device includes a first seal between the first outer end face and the fluid passage. The feedthrough device includes a second seal between the second outer end face and the fluid passage. The outer surface includes a cylindrical outer face of the feedthrough body. The first outer end face is a first axial end of the feedthrough body. The second outer end face is a second axial end of the feedthrough body. The first seal and the second seal are both O-rings.
Additionally or alternatively, these and other implementations may include one or more of the following features. The conductor defines a solid conductive cross-section through the cavity. The feedthrough device includes a second conductor extending through the feedthrough body from the first end face, through the cavity, to the second end face. The second conductor defines a second solid conductive cross-section through the cavity. The body is an integral structure made of nonconductive material.
In some aspects, a fuel injector system includes a partition between a high pressure zone and a low pressure zone. The fuel injector system includes a feedthrough device disposed in the partition between the high pressure zone and the low pressure zone. The feedthrough device includes a first end face exposed to the high pressure zone and a second end face exposed to the low pressure zone. The feedthrough device includes a first seal that isolates an interior volume of the feedthrough device from the high pressure zone. The feedthrough device includes a second seal that isolates the interior volume of the feedthrough device from the low pressure zone. The fuel injector system includes a conductor extending through the feedthrough device from the high pressure zone, through the first end face, through the interior volume, through the second end face, to the low pressure zone. The fuel injector system includes a fluid passage that allows fluid communication between the interior volume and an exterior.
Implementations may include one or more of the following features. The fuel injector system includes a sensor. The sensor includes a pressure sensor, a fuel sensor, or both. The low pressure zone includes an internal volume of the fuel injector system. The fuel injector system includes a solenoid assembly in the high pressure zone. The conductor is configured to communicate a control signal between the solenoid assembly in the high pressure zone and an external control system in the low pressure zone. The partition includes a chamber that contains inert gas. The inert gas is contained within the chamber at a pressure that is higher than the pressure of the high pressure zone of the fuel injector system.
In some aspects, an electrical signal is sent from a low pressure zone of a fuel injector system to a high pressure zone of the fuel injector system through a feedthrough device. The feedthrough device has an internal volume that is sealed from the low pressure zone and the high pressure zone. A condition of the internal volume of the feedthrough device is sensed.
Implementations may include one or more of the following features. Sensing the condition includes sensing a pressure of the internal volume. Sensing the condition includes sensing a fuel content of the internal volume. An internal leak in the feedthrough device is identified based on the condition. Sending the electrical signal operates a solenoid assembly in the high pressure zone. The electrical signal is received from a controller in the low pressure zone.
The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.
Like reference symbols in the various drawings indicate like elements.
A fuel injector system can include additional or different features; and the features of the example fuel injector system 100 can be arranged in the manner shown in
In the example shown in
The high pressure zones 103, 104 include the solenoid assembly 106, portions of the conductors 107a, 107b, and possibly other components of the fuel injector system 100. The high pressure zones 103, 104 can be at the same pressure or they can be at different pressures. For example, when solenoid assembly 106 is pressure-balanced, the high pressure zones 103, 104 can be at different pressures, when solenoid assembly 106 is not pressure-balanced, the high pressure zones 103, 104 can be at the same pressure. In some cases, the high pressure zones 103, 104 are sealed from each other, or fluid communication may be permitted between the low pressure zones 103, 104. The high pressure zone 104 can contain a combustible fuel mixture at high pressure during operation of the fuel injector system 100. For example, the high pressure zone 104 can contain fluids at pressures that are significantly higher than the low pressure zone 102. In some implementations, the high pressure zone 104 contains fluids at pressures on the order of 160 psi; or the high pressure zone 104 can contain fluids at different (lower or higher) pressures.
The partition 105 can prevent fluid communication between the low pressure zone 102 and the high pressure zone 104. For example, the partition 105 can be part of a housing or another structure of the fuel injector system 100. The partition 105 can be made of aluminum, steel, plastics, a different material, or a combination of materials. The partition 105 can be made of one or more parts formed by machining, casting, molding, other manufacturing processes. The partition 105 includes a port that houses the feedthrough device 108. The partition 105 also includes the leak-detection port 110 that provides fluid communication between the sensor 112 and the port that houses the feedthrough device 108.
The solenoid assembly 106 is contained in the high pressure zone 104 of the example fuel injector system 100. The solenoid assembly 106 can control a flow of fuel into an internal combustion engine. In some cases, the solenoid assembly 106 can include a plunger or another type of actuator that opens and closes a fuel injection port. In some cases, the actuator of the solenoid assembly 106 moves at an operating frequency of the solenoid (e.g., 5 Hz, 10 Hz, 50 Hz, 100 Hz, etc.). Movement of the actuator can be controlled, for example, by a magnetic field produced by a conductive coil of the solenoid assembly 106. The conductive coil can produce the magnetic field based on an electrical signal (e.g., a direct current signal that is modulated over time, etc.) carried by the conductors 107a, 107b.
The conductors 107a, 107b carry an operating signal from the external controller 114 to the solenoid assembly 106. For example, the conductors 107a, 107b can form a closed-loop circuit with the solenoid assembly 106 and the controller 114. The conductors 107a, 107b can carry an alternating current, direct current, or another type of signal. The conductors 107a, 107b can be configured to carry a signal having a voltage in the operating range of the solenoid assembly 106. In some implementations, the conductors 107a, 107b carry a signal having a maximum voltage between 90 and 140 Volts; or the conductors 107a, 107b can carry a signal having a lower or higher maximum voltage (e.g., 18 Volts, 180 Volts). Although two conductors are shown in
The conductors 107a, 107b can be made of copper, brass, gold, a different conducting material, or a combination of them. The conductors can include lengths of braided wire, solid wire, leads, soldered junctions, or a combination of these and other components. In some implementations, the conductors 107a, 107b are each conductively connected (e.g., soldered) to a first pair of terminals at the controller 114 and a second pair of terminals at the solenoid assembly 106.
The conductors 107a, 107b extend from the low pressure zone 102, through the feedthrough device 108, into the high pressure zone 104. The feedthrough device 108 provides a pressure-sealed conductive path through the partition 105. The example feedthrough device 108 shown in
The example feedthrough device 108 includes a provision to allow detection of leakage in the feedthrough device 108 itself. For example, an internal cavity in the feedthrough device 108 can function as a leak-detection zone. The leak-detection zone can be exposed to all conductors within the feedthrough device 108, and it can be isolated from both the fuel source and the ambient environment. In some examples, the feedthrough device 108 includes two independent seals, such that fuel leaking through the first seal cannot travel from the first seal to the second seal without passing through the leak-detection zone. Moreover, the leak-detection zone can be connected to a leak detection system, a pressurized leak-prevention system, or another mechanism.
In the event that the feedthrough device 108 develops a leak, high pressure fluids from the high pressure zone 104 can be collected in the leak-detection zone of the feedthrough device 108, and the leak-detection zone of the feedthrough device 108 can communicate the high pressure fluids through the leak-detection port 110 to the sensor 112. As such, a leak in the feedthrough device 108 can be detected, in some cases, by sensing an increased pressure in the leak-detection port 110. In some instances, the fluids leaked from the high pressure zone 104 contain fuel (e.g., hydrocarbon gas). As such, a leak in the feedthrough device 108 can be detected, in some cases, by sensing a fuel concentration or fuel content in the leak-detection port 110.
In some example implementations, the feedthrough device 108 includes an internal cavity and a fluid passage; the fluid passage provides fluid communication between the internal cavity and the leak-detection port 110. In the event that the feedthrough device 108 develops a leak, fluids leaked from the high pressure zone 104 can be communicated through the internal leak-detection zone the feedthrough device 108 and into the leak-detection port 110. For example, the feedthrough device 108 can be configured to accumulate any such leaked fluids in the internal cavity, and the fluid passage of the feedthrough device 108 can communicate the leaked fluids from the internal cavity into the leak-detection port 110. The leak-detection port 110 provides a fluid communication path from the feedthrough device 108 to the sensor 112. In the event that the feedthrough device 108 develops a leak, the leak-detection port 110 can communicate the leaked fluids from the feedthrough device 108 to the sensor 112.
In some example implementations, each of the conductors 107a, 107b is sealed from the fuel pressure source (i.e., the high pressure zone 104) by a first seal at or near a point where the conductor enters the internal cavity of the feedthrough device 108; and each of the conductors 107a, 107b is sealed from the low pressure zone 102 by a second seal at or near the point where the conductor exits the internal cavity of the feedthrough device 108. Upon failure of the first seal, leakage through the feedthrough device 108 can be detected via a passage connected to the internal cavity, while the second seal prevents leakage to the external environment. As such, the internal cavity can operate as a leak-detection zone for the feedthrough device 108.
The sensor 112 can be configured to detect a condition that indicates a leak in the feedthrough device 108. In some implementations, the sensor 112 is a pressure sensor. For example, the sensor 112 can be configured to detect static pressure, pressure changes, or other types of pressure conditions. In some implementations, the sensor 112 is a fuel sensor. For example, the sensor 112 can be configured to detect fuel content, fuel concentration, or other types of fluid properties. The sensor 112 may be connected to the controller 114, another type of processor, or an external monitoring system. The example sensor 112 is disposed in a position where it can sense a condition of the internal volume of the feedthrough device 108. The sensor 112 can be installed within the leak-detection port 110, in a low pressure or high pressure zone outside of the leak-detection port 110, or in another area. In some cases, the sensor 112 is omitted from the fuel injector system 100.
The sensor 112 can be part of a monitoring system that includes other components (not shown in the figure). The sensor 112 can be part of a pressure detection system. The pressure detection system can include a fixed volume in which the pressure increase from the accumulation of the leaking fuel can be detected using a pressure sensor. The sensor 112 can be included in a fuel detection system (e.g., a methane detector, etc.).
In some examples, the sensor 112 is a dedicated sensor for the leak-detection port 110. As such, the conditions detected by the sensor 112 may directly indicate whether a leak has formed in the feedthrough device 108. In some examples, the sensor 112 receives fluid from the leak-detection port 110 and other leak-detection ports at other locations in the fuel injector system 100. As such, the conditions detected by the sensor 112 may indicate whether a leak has formed at any of several locations in the fuel injector system 100. In some implementations, the fuel injector system 100 is contained in an external housing or another type of external enclosure (not shown in the figure), and the sensor 112 is configured to detect any leakage within the enclosure.
In some implementations, the leak-detection port 110 is filled with high pressure inert gas (e.g., air, nitrogen, etc.). The high pressure inert gas in the leak-detection port 110 can prevent or reduce leaking of fuel through the feedthrough device 108 to an external environment. The high pressure inert gas in the leak-detection port 110 can be maintained at a pressure that is higher than the pressure within the high pressure zone 104. If a leak occurs in the feedthrough device 108, the pressure of the inert gas in the leak-detection port 110 can, in some cases, minimize or reduce the amount of fuel that escapes from the high pressure zone 104 through the leak. As such, a leak in the feedthrough device 108 can be rendered inert through the introduction of the high pressure inert fluid. In some cases, the inert gas in the leak-detection port 110 can flood the internal volume of the feedthrough device 108.
In some aspects of operation, the controller 114 sends an electrical signal from the low pressure zone 102 to the high pressure zone 104 through the feedthrough device 108. The electrical signal from the controller 114 (in the low pressure zone 102) operates the solenoid assembly 106 (in the high pressure zone 104). The feedthrough device 108 has an internal cavity that is sealed from the low pressure zone 102 and the high pressure zone 104. The internal cavity can communicate fluid into the leak-detection port 110, so that the sensor 112 can sense a condition of the internal volume of the feedthrough device 108.
In some aspects of operation, the sensor 112 can produce an output that indicates (e.g., directly or indirectly) whether there is a leak in the feedthrough device 108. For example, if the feedthrough device 108 develops a leak, the combustible, high pressure fuel from the high pressure zone 104 is collected in the internal cavity of the feedthrough device 108 and communicated to the sensor 112. In some instances, the sensor 112 senses the pressure, fuel content, or another condition of the internal cavity of the feedthrough device 108. The conditions sensed by the sensor can be communicated to the controller 114 or another external system, which can produce a signal or another appropriate output to indicate whether a leak has been detected. If a leak is detected, an appropriate action can be initiated, such as, for example, powering down all or part of the system. In some examples, potential external leak paths of the fuel valve can be pressurized to a pressure that is equal to, or higher than, the inlet pressure of the fuel valve. In such cases, a fuel valve “leak” would simply result in flow of the leak system pressurized media into the fuel valve.
The feedthrough device 200 can be used or adapted to provide a pressure-sealed conductive pathway between any two zones of different pressures. The pressure difference between the two zones can range from small pressure differences (e.g., 10 psi) in some applications to larger pressure differences (e.g., 10,000 psi) in other applications. As such, in some instances, the dimensions, materials, and features of the example feedthrough device 200 can be adapted for particular applications other than a fuel injector system.
As shown in
The example feedthrough body 202 includes a first outer end face 210a at a high pressure end of the feedthrough body 202. The feedthrough body 202 includes a second outer end face 210b at a low pressure end of the feedthrough body 202. The first outer end face 210a and the second outer end face 210b are at opposite ends of the feedthrough body 202. The feedthrough body 202 includes an outer surface 208 between the first outer end face 210a and the second outer end face 210b.
The example feedthrough body 202 has a generally cylindrical geometry, with the first outer end face 210a defining a first axial end of the feedthrough body 202 and the second outer end face 210b defining a second axial end of the feedthrough body 202. The outer surface 208 generally defines an outer circumference of the feedthrough body 202. In particular, the outer surface 208 includes cylindrical faces 212a, 212b, 212c, 212d, and seals 206a, 206b, 206c between the cylindrical faces. In the example shown, the seals 206a, 206b, 206c are all O-rings. Other types of seals can be used.
The example feedthrough body 202 is a continuous structure between the first and second outer end faces 210a, 210b. In some implementations, a feedthrough body includes multiple components. For example, a feedthrough body can be made of two components separated by a gap, where one of the components carries one or more seals (e.g., 206a, 206b) on the high-pressure side and a separate component carries one or more seals (e.g., 206c) on the low-pressure side. The two separate components can abut each other, or they can be separated by open space.
The feedthrough body 202 can include additional or different types of seals, including seals in other locations. In some implementations, the feedthrough body 202 includes an internal seal on each side of the feedthrough body. For example, the feedthrough body 202 can include seals about the conductors 204a, 204b at the first and second outer end faces 210a, 210b, at the interior surface 214, between an outer end face and the interior surface 214, or in multiple locations within the feedthrough body. The seals about the conductors 204a, 204b can prevent high pressure gas from leaking between the feedthrough body 202 and the conductors 204a, 204b. The seals can include, for example, O-rings, adherent compounds, compressive joints, etc.
When the feedthrough device 200 is installed (e.g., in a fuel injector system) between a high pressure zone and a low pressure zone, the feedthrough body 202 can prevent fluid communication between the low pressure zone and the high pressure zone. For example, the feedthrough body 202 can be installed in a port through a housing or another structure, and the seals 206a, 206b, 206c can form a pressure seal in the port. The feedthrough body 202 can be made of epoxy, a different kind of nonconductive material, or a combination of materials. In some cases, the feedthrough body 202 is an integral structure made of nonconductive material. The feedthrough body 202 can be formed by molding, machining, casting, or other manufacturing processes.
The example feedthrough body 202 includes an interior surface 214 defining the internal cavity 216. The internal cavity 216 is disposed between the first outer end face 210a and the second outer end face 210b. The internal cavity 216 is enclosed on multiple sides. For example, the internal cavity 216 is enclosed by the interior surface 214 that includes an internal face on the high pressure side of the feedthrough body 202 and an opposing internal face on the low pressure side of the feedthrough body 202. The interior surface 214 also includes a cylindrical internal face between the opposing low pressure and high pressure sides. The internal cavity 216 is not fully enclosed. In particular, the feedthrough body 202 includes a fluid passage 218 through the outer surface 208, which allows fluid communication between the internal cavity 216 and an exterior of the feedthrough body 202.
Both conductors 204a, 204b extend through the example feedthrough body 202 from the first outer end face 210a, through the internal cavity 216, to the second outer end face 210b. The example conductors 204a, 204b shown in
The example feedthrough body 202 includes seals to prevent fluid leaks. The seal 206a provides a first seal on the high pressure side of the feedthrough body 202. The seal 206b provides a second seal on the high pressure side of the feedthrough body 202. The seals 206a, 206b seal between the first outer end face 210a and the internal cavity 216. The seal 206c provides a third seal on the low pressure side of the feedthrough body 202. The seal 206c seals between the second outer end face 210b and the internal cavity 216.
The second and third seals (206b, 206c) define an internal volume of the example feedthrough body 202 between the first outer end face 210a and the second outer end face 210b. The internal volume includes the internal cavity 216 and the fluid passage 218 through the outer surface 208. When the example feedthrough device 200 is installed (e.g., in a fuel injector system), the internal volume can be placed in fluid communication with an external fluid passage (e.g., the leak-detection port 110 in
The internal volume of the example feedthrough device 200 can provide an internal leak-detection zone. In some instances, the structure of the feedthrough device 200 causes any fluid leaked from the high pressure side to flow into the internal volume (e.g., into the internal cavity 216). For example, the solid current-carrying interconnects within the internal cavity 216 in the example shown in
While this specification contains many details, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of features specific to particular examples. Certain features that are described in this specification in the context of separate implementations can also be combined. Conversely, various features that are described in the context of a single implementation can also be implemented separately or in any suitable subcombination.
A number of examples have been shown and described. Nevertheless, it will be understood that various modifications can be made. Accordingly, other embodiments are within the scope of the following claims.
