Patent Application
20160201611
The subject matter disclosed herein relates to sensors for determining characteristics of turbochargers within combustion engines.
Combustion engines, such as rotary engines and turbine engines, combust fuel to generate motion (e.g., rotary motion) of certain interior components within the engine which is then typically used to power a drive train, a generator, or other useful system. Combustion engines typically combust a carbonaceous fuel, such as natural gas, gasoline, diesel, and the like, and use the corresponding expansion of high temperature and pressure gases to apply a force to certain components of the engine, e.g., piston disposed in a cylinder, to move the components over a distance. Each cylinder may include one or more valves that open and close correlative with combustion of the carbonaceous fuel. For example, an intake valve may direct an oxidant such as air into the cylinder, which is then mixed with fuel and combusted. Combustion fluids, e.g., hot gases, may then be directed to exit the cylinder via an exhaust valve. The engine may include a turbocharger to increase the pressure and/or quantity of air that combines with the fuel within the cylinder. The turbocharger may work by rotating two sides of a rotor. The first receives pressure from exhaust gas which rotates blades of the turbocharger. The other side of the turbocharger also has blades that spin and force additional oxidant into the cylinder of the engine. Accordingly, the carbonaceous fuel is transformed into mechanical motion, useful in driving a load. For example, the load may be a generator that produces electric power.
Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a system includes a turbocharger and at least one sensor disposed adjacent the turbocharger. The at least one sensor is configured to detect one or more resonance frequencies of the turbocharger. The system also includes a controller configured to receive a signal from the at least one sensor representative of the detected one or more resonance frequencies of the turbocharger and to analyze the one or more resonance frequencies to determine one or more characteristics of the turbocharger.
In a second embodiment, a system includes a controller configured to receive a signal from at least one sensor disposed adjacent a turbocharger, sample the signal to produce a sampled signal, filter the sampled signal to detect one or more resonance frequencies to the turbocharger, and analyze the resonance frequencies to determine one or more characteristics of the turbocharger.
In a third embodiment, a method includes receiving a signal from a sensor disposed adjacent a turbocharger, sampling the signal to produce a sampled signal, filtering the sampled signal to detect one or more resonance frequencies to the turbocharger, and analyzing the resonance frequencies to determine one or more characteristics of the turbocharger.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
Turning to the drawings,
The combustion chamber 12 is also configured to receive a fuel 18 (e.g., a liquid and/or gaseous fuel) from a fuel supply 19, and a fuel-air mixture ignites and combusts within each combustion chamber 12. The hot pressurized combustion gases cause a piston 20 adjacent to each combustion chamber 12 to move linearly within a cylinder 26 and convert pressure exerted by the gases into a rotating motion, which causes a shaft 22 to rotate. Further, the shaft 22 may be coupled to a load 24, which is powered via rotation of the shaft 22. For example, the load 24 may be any suitable device that may generate power via the rotational output of the system 10, such as an electrical generator. Additionally, although the following discussion refers to air as the oxidant 16, any suitable oxidant may be used with the disclosed embodiments. Similarly, the fuel 18 may be any suitable gaseous fuel, such as natural gas, associated petroleum gas, propane, biogas, sewage gas, landfill gas, coal mine gas, for example.
The system 8 disclosed herein may be adapted for use in stationary applications (e.g., in industrial power generating engines) or in mobile applications (e.g., in cars or aircraft). The engine 10 may be a two-stroke engine, three-stroke engine, four-stroke engine, five-stroke engine, or six-stroke engine. The engine 10 may also include any number of combustion chambers 12, pistons 20, and associated cylinders (e.g., 1-24). For example, in certain embodiments, the system 8 may include a large-scale industrial reciprocating engine having 4, 6, 8, 10, 16, 24 or more pistons 20 reciprocating in cylinders. In some such cases, the cylinders and/or the pistons 20 may have a diameter of between approximately 13.5-34 centimeters (cm). In some embodiments, the cylinders and/or the pistons 20 may have a diameter of between approximately 10-40 cm, 15-25 cm, or about 15 cm. The system 10 may generate power ranging from 10 kW to 10 MW. In some embodiments, the engine 10 may operate at less than approximately 1800 revolutions per minute (RPM). In some embodiments, the engine 10 may operate at less than approximately 2000 RPM, 1900 RPM, 1700 RPM, 1600 RPM, 1500 RPM, 1400 RPM, 1300 RPM, 1200 RPM, 1000 RPM, 900 RPM, or 750 RPM. In some embodiments, the engine 10 may operate between approximately 750-2000 RPM, 900-1800 RPM, or 1000-1600 RPM. In some embodiments, the engine 10 may operate at approximately 1800 RPM, 1500 RPM, 1200 RPM, 1000 RPM, or 900 RPM. Exemplary engines 10 may include General Electric Company's Jenbacher Engines (e.g., Jenbacher Type 2, Type 3, Type 4, Type 6 or J920 FleXtra) or Waukesha Engines (e.g., Waukesha VGF, VHP, APG, 275GL), for example.
The driven power generation system 8 may include one or more knock sensors 23 suitable for detecting engine “knock.” The knock sensor 23 may be any sensor configured to sense vibrations caused by the engine 10, such as vibration due to detonation, pre-ignition, and or pinging. The knock sensor 23 is shown communicatively coupled to an engine control unit (ECU) 25. During operations, signals from the knock sensor 23 are communicated to the ECU 25 to determine if knocking conditions (e.g., pinging) exist. Additionally, the knock sensor 23 may detect vibrations from the turbocharger 17 that indicate certain characteristics of the engine 10 and/or the turbocharger 17. The ECU 25 may then adjust certain engine 10 parameters to ameliorate or eliminate the conditions of the engine 10 and/or the turbocharger 17. For example, the ECU 25 may adjust ignition timing and/or adjust boost pressure to eliminate the knocking. As further described herein, the knock sensor 23 may additionally derive that certain vibrations should be further analyzed and categorized to detect, for example, speed of a turbocharger.
As shown, the piston 20 is attached to a crankshaft 54 via a connecting rod 56 and a pin 58. The crankshaft 54 translates the reciprocating linear motion of the piston 24 into a rotating motion. As the piston 20 moves, the crankshaft 54 rotates to power the load 24 (shown in
Referring back to
During operations, when the piston 20 is at the highest point in the cylinder 26 it is in a position called top dead center (TDC). When the piston 20 is at its lowest point in the cylinder 26, it is in a position called bottom dead center (BDC). As the piston 20 moves from top to bottom or from bottom to top, the crankshaft 54 rotates one half of a revolution. Each movement of the piston 20 from top to bottom or from bottom to top is called a stroke, and engine 10 embodiments may include two-stroke engines, three-stroke engines, four-stroke engines, five-stroke engine, six-stroke engines, or more.
During engine 10 operations, a sequence including an intake process, a compression process, a power process, and an exhaust process typically occurs. The intake process enables a combustible mixture, such as fuel and air, to be pulled into the cylinder 26, thus the intake valve 62 is open and the exhaust valve 64 is closed. The compression process compresses the combustible mixture into a smaller space, so both the intake valve 62 and the exhaust valve 64 are closed. The power process ignites the compressed fuel-air mixture, which may include a spark ignition through a spark plug system, and/or a compression ignition through compression heat. The resulting pressure from combustion then forces the piston 20 to BDC. The exhaust process typically returns the piston 20 to TDC while keeping the exhaust valve 64 open. The exhaust process thus expels the spent fuel-air mixture through the exhaust valve 64. It is to be noted that more than one intake valve 62 and exhaust valve 64 may be used per cylinder 26.
The depicted engine 10 also includes a crankshaft sensor 66, the knock sensor 23, and the engine control unit (ECU) 25, which includes a processor 72 and memory 74. The crankshaft sensor 66 senses the position and/or rotational speed of the crankshaft 54. Accordingly, a crank angle or crank timing information may be derived. That is, when monitoring combustion engines, timing is frequently expressed in terms of crankshaft 54 angle. For example, a full cycle of a four stroke engine 10 may be measured as a 720° cycle. The knock sensor 23 may be a Piezo-electric accelerometer, a microelectromechanical system (MEMS) sensor, a Hall effect sensor, a magnetostrictive sensor, and/or any other sensor designed to sense vibration, acceleration, sound, and/or movement. In other embodiments, sensor 23 may not be a knock sensor in the traditional sense, but any sensor that may sense vibration, pressure, acceleration, deflection, or movement.
Because of the percussive nature of the engine 10, the knock sensor 23 may be capable of detecting signatures even when mounted on the exterior of the cylinder 26. However, the knock sensor 23 may be disposed at various locations in or about the cylinder 26. Additionally, in some embodiments, a single knock sensor 23 may be shared, for example, with one or more adjacent cylinders 26, or between a cylinder 26 and the turbocharger 17. In other embodiments, each cylinder 26 and the turbocharger 17 may include one or more knock sensors 23. The crankshaft sensor 66 and the knock sensor 23 are shown in electronic communication with the engine control unit (ECU) 25. The ECU 25 includes a processor 72 and a memory 74. The memory 74 may store computer instructions that may be executed by the processor 72. The ECU 25 monitors and controls and operation of the engine 10, for example, by adjusting combustion timing, valve 62, 64, timing, adjusting the delivery of fuel and oxidant (e.g., air), and so on.
Advantageously, the techniques described herein may use the ECU 25 to receive data from the crankshaft sensor 66 and the knock sensor 23, and then to creates a “noise” signature by plotting the knock sensor 23 data against the crankshaft 54 position. The ECU 25 may then go through the process of analyzing the data to derive normal (e.g., known and expected noises) and abnormal signatures (e.g., unknown or unexpected noises). The ECU 25 may then characterize the abnormal signatures, as described in more detail below. These signatures may be compiled into a lookup table that may be stored on the memory 74 for later use during operation of the engine 10. For example, the exact engine 10 may be tested prior to installation into within the system 8 and the signatures saved during such testing. Additionally, the lookup table may be supplied by testing engines 10 of the same model. That is, by storing and compiling operation data from one or more engines 10 of the same type (e.g., make, model, version, etc.), an accurate signature may be stored for a newly installed engine 10. By providing for signature analysis, the techniques described herein may enable a more optimal and a more efficient operations and maintenance of the engine 10.
During the second knock event 90 in the illustrated embodiment, the engine 10 begins to discharge less exhaust and the resonance frequencies 96 also drop. The drop in frequency 84 corresponds to a drop in the speed of the turbocharger 17 and a drop in air 16 being forced into the cylinder 26. The spectrogram 80 thus shows that the sensor 23 may detect knock events (e.g., 88, 90) and resonance frequencies 96 of a turbocharger 17 simultaneously. Furthermore, the sensor 23 does not have to detect a knock event to detect resonance frequencies 96. Therefore, the sensor 23 may send only the resonance frequency 96 information to the ECU 25 in order to determine the speed of the turbocharger 17.
Next in the process 100, the ECU 25 samples 104 the signal to produce a sampled signal. The ECU 25 may have a sample rate that varies in response to engine 10 conditions. For example, during startup of the engine 10, the ECU 25 may sample at a faster rate to improve accuracy of the sample signal. On the other hand, during continuous operation of the engine 10, the ECU 25 may sample the signal at a slower rate, because the signal is more likely to be the same over a longer period of time. The signal is likely to be the same due to the constant speed at which the turbocharger 17 is expected to be rotating. During shutdown of the engine 10, the turbocharger 17 is likely to be changing speed, and therefore the sampling rate may be increased.
The process 100 also involves filtering 106 the sampled signal to detect one or more resonance frequencies of the turbocharger 17. Filtering the sampled signal may involve removing frequencies that are known to be generated by the engine 10 and not the turbocharger 17. For example, certain embodiments of the engine 10 may operate with a vibration frequency of 375 Hz. By using a low-pass filter of 375 Hz, the sampled signal may more accurately reflect the frequencies that are being produced by the turbocharger 17. The filtered frequencies may indicate the speed or other characteristics of the turbocharger 17, and therefore the ECU 25 may analyze 108 the resonance frequencies to determine one or more characteristics of the turbocharger 17. Analyzing may involve comparing the filtered frequencies to frequencies stored in a lookup table, as outlined above. The lookup table may be stored within the memory of the ECU 25 based on previous testing of the engine 10, or by testing or modeling of similar engines 10. After the results are analyzed, the ECU 25 outputs 110 an analysis for the speed of the turbocharger 17. The analysis may trigger the engine 10 to adjust operating parameters such as timing and fuel injection to compensate for any changes from the turbocharger 17.
Technical effects of the invention include increasing efficiency of engines 10 that include a turbocharger 17. The ECU 25 disclosed herein receives signals from one or more sensors 23 that indicate conditions and operating parameters of the turbocharger 17. The engine 10 may then efficiently react to the conditions and operating parameters to reduce pinging and fuel consumption, and increase the useful life to the engine 10 and engine components.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
