Patent ID: 12203920

DETAILED DESCRIPTION

The present disclosure relates to systems and methods for detecting metallic chips in engine (e.g., lubricating, cooling) fluids. In some embodiments, the systems and methods described herein may help assess a condition of an engine by using one or more multi-zone magnetic chip detectors to reduce the probability of generating nuisance chip detections and associated annunciations or alarms. For example, the systems and methods described herein may reduce the probability of nuisance chip detections associated with the accumulation of acceptable smaller/fine magnetic debris/particles, commonly referred to as “fuzz” at a magnetic chip detector immersed in lubricating fluid. Some fuzz can be generated during the normal operation of an aircraft engine and may not necessarily be indicative of a developing or impending mechanical problem. For example, such fuzz can normally be generated during the initial period (e.g., a few hundred hours) of operation of an aircraft engine following initial entry into service or following extensive maintenance such as an overhaul. This initial period is also known as the engine's “break-in” period. Chip detections caused by the accumulation of the acceptable and relatively harmless fuzz, during the break-in period for example, oppose the design intent of the magnetic chip detector and are undesirable since they do not provide an accurate indication of a possible developing or impending problem.

Metallic chips that are carried by the lubricating fluid may be from metallic engine parts such as gear teeth or bearings for example. Some disc type magnetic chip detectors use one disk-shaped magnet placed in a non-conductive and non-magnetically permeable isolator with two conductive steel end caps which, in combination, create a single chip capture zone. When a metallic chip of a sufficient size is attracted to the capture zone by the magnet, the metallic chip bridges (e.g., short-circuits) the gap between the steel end caps to complete an electric circuit that includes the gap. A controller or other annunciation circuitry connected to the magnetic chip detector may detect this change in resistance caused by the metallic chip and indicate to a pilot of the aircraft via a cockpit indication the presence of one or more magnetic chips having been detected by the magnetic chip detector.

Magnetic chip detectors may use rare earth magnets that provide a relatively high capture efficiency. This can result in a high sensitivity of a magnetic chip detector, which may increase the probability of nuisance detections. For example, a magnetic chip detector with a single capture zone may function as an on/off switch and may trigger an annunciation based on a relatively harmless single metallic filament having been captured in the single capture zone. Once the chip detection is triggered by one or more chips, the pilot may be required to abort the mission mid-flight, return to the ground (e.g., base) as soon as possible, and remove (or have maintenance personnel remove) the magnetic chip detector for visual inspection. The visual inspection verifies whether significant debris has been collected by the magnetic chip detector and hence whether maintenance is required before the aircraft can be dispatched again. If the detection is triggered by an insignificant metallic filament or other insignificant metallic particle(s), such detection can be a nuisance to the pilot and/or aircraft operator.

In some embodiments, the magnetic chip detectors described herein may reduce the probability of single chip detections and other nuisance detection events. In some embodiments, the magnetic chip detectors described herein may reduce the probability of fuzz-induced nuisance detections. In some embodiments, the magnetic chip detectors described herein may provide an indication of a degree of contamination that allows a system to discriminate between harmless/tolerable contamination and gross contamination indicative of a developing and/or impending mechanical problem. In some embodiments, the magnetic chip detectors described herein may provide an ability to discriminate between small or large chips being detected.

In some embodiments, the magnetic chip detectors described herein may provide a more informative indication via a single interface, which may facilitate installation (e.g., retrofitting) into existing engines and associated controllers by not requiring an increased number of inputs to the controller or aircraft. In some embodiments, the magnetic chip detectors described herein may permit the monitoring of different regions of a fluid (e.g., lubrication, cooling) system of an aircraft engine via the single interface.

Aspects of various embodiments are described through reference to the drawings. Even though the description below is provided in relation to lubricating fluid, it is understood that some embodiments of the magnetic chip detectors, systems and methods described herein may also be used on other types of engine fluids such as engine coolant for example.

The term “connected” may include both direct connection (in which two elements that are connected to each other contact each other) and indirect connection (in which at least one additional element is located between the two elements).

The term “substantially” as used herein may be applied to modify any quantitative representation which could permissibly vary without resulting in a change in the basic function to which it is related.

FIG.1is a schematic axial cross-section view of aircraft engine10(referred hereinafter as “engine10”) of a turbofan gas turbine engine preferably provided for use in subsonic flight, generally comprising, in serial flow communication, fan12through which ambient air is propelled, multistage compressor14for pressurizing the air, combustor16in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and turbine section18for extracting energy from the combustion gases. Engine10may be mounted to an aircraft and used to propel such aircraft. Even thoughFIG.1shows engine10being of the turbofan type, it is understood that aspects of the present disclosure are also applicable to other (e.g., turboshaft, turboprop, internal combustion) types of aircraft engines.

Engine10may include lubrication (and/or other fluid) system20shown schematically and partially inFIG.1. Lubrication system20may serve to lubricate, cool and clean one or more lubrication loads22such as bearings and gears of engine10. Lubrication system20may include tank24and other components such as one or more pumps, one or more valves, and one or more filters. Tank24may be a reservoir containing a supply of lubricating fluid26such as oil for use by lubrication system20. Lubrication system20may include one or more magnetic chip detectors (MCDs)28. For example, lubrication system20may include a single MCD28or a plurality of MCDs28disposed at different locations within lubrication system20. MCD28may be at least partially immersed in lubricating fluid26during operation. For example, MCD28be disposed inside tank24, inside a gearbox, or in a scavenge line.

MCD28may be part of chip detection system30(referred hereinafter as “system30”) and may be associated with and/or may be part of engine10. System30may include controller32or other detection circuitry operatively connected to MCD28. In various embodiments, controller32may include or form part of a Full Authority Digital Engine Control (FADEC) which may, for example, include one or more digital computer(s) or other data processors, sometimes referred to as electronic engine controller(s) (EEC) and related accessories that control at least some aspects of performance of engine10. Controller32may, for example, be configured to make decisions regarding the control of engine10. Controller32may include one or more data processors and non-transitory machine-readable memory. Controller32may receive input(s) from MCD28, perform one or more procedures or steps defined by instructions stored in the memory to generate output(s) such as triggering a suitable annunciation to a pilot of the aircraft for example. Various aspects of the present disclosure may be embodied as systems, devices, methods and/or computer program products.

FIG.2Ais an exemplary schematic representation of MCD28shown a as part of chip detection system30of engine10, andFIG.2Bis a schematic representation of electric circuit34associated with MCD28. MCD28may include two or more magnetic chip capture zones36A,36B to thereby reduce the probability of single-chip and/or fuzz-induced nuisance detections. MCD28may include first capture zone36A and second capture zone36B. First capture zone36A may include first electrically conductive terminal38A (referred hereinafter as “first MCD terminal38A”) spaced apart from second electrically conductive terminal38B (referred hereinafter as “second MCD terminal38B”) to define first chip-receiving gap G1(referred hereinafter as “first gap G1”) therebetween. Second capture zone36B may include third electrically conductive terminal38C (referred hereinafter as “third MCD terminal380”) spaced apart from second MCD terminal38B to define second chip-receiving gap G2(referred hereinafter as “second gap G2”) therebetween. The size(s) of first gap G1and of second gap G2may be selected based on the chip sizes of interest. In some embodiments, the size(s) of first gap G1and second gap G2may be between 1/64″ (0.4 mm) and ⅛″ (3.2 mm) for example.

MCD28may be an axial disk-type magnetic chip detector. However, aspects of the present disclosure are also applicable to other types of magnetic chip detectors such as prong-type magnetic chip detectors as explained further below. For example, MCD28may include first magnet40A disposed and retained between first MCD terminal38A and second MCD terminal38B. MCD28may include second magnet40B disposed and retained between third MCD terminal38C and second MCD terminal40C. Suitable electrically non-conductive and non-magnetically permeable isolators (not shown) may be disposed between first magnet40A and the respective first MCD terminal38A and second MCD terminal38B. First MCD terminal38A and second MCD terminal38B may be metallic (e.g., steel) end caps between which first magnet40A is retained. Similarly, second magnet40B may be disposed and retained between second MCD terminal38B and third MCD terminal38C. Suitable electrically non-conductive and non-magnetically permeable isolators (not shown) may be disposed between second magnet40B and the respective second MCD terminal38B and third MCD terminal38C. Second MCD terminal38B and third MCD terminal38C may be metallic (e.g., steel) end caps between which second magnet40B is retained. In some embodiments, second MCD terminal38B may be common to both first capture zone36A and second capture zone36B and may be a double-sided end cap that is sandwiched between first magnet40A and second magnet40B.

In some embodiments, first magnet40A, second magnet40B, first MCD terminal38A, second MCD terminal38B, and third MCD terminal38C may be disk-shaped and may be disposed in a coaxial manner along axis A. In some embodiments, first magnet40A, second magnet40B, first MCD terminal38A, second MCD terminal38B, and third MCD terminal38C may be integrated/assembled into a single metallic chip detector that may be disposed in a single region of lubrication system20(shown inFIG.1) of engine10. For example, both first capture zone36A and second capture zone36B may be in fluid communication with each other during use when MCD28is immersed in lubricating fluid26. MCD28could also be configured to define one or more additional capture zones by adding additional magnet(s) and end cap(s).

FIG.2Aalso illustrates a situation where: first metallic chip42A has been captured by first capture zone36A and electrically bridges first gap G1; and second metallic chip42B has been captured by second capture zone36B and electrically bridges second gap G2.

Electric circuit34may include first output terminal44A and second output terminal44B together defining a single interface between MCD28and controller32. As shown inFIG.2B, electric circuit34may include both first gap G1and second gap G2. Electric resistance value RV across first output terminal44A and second output terminal44B may serve as a single output communicated to controller32as an indication of whether or not a chip detection has occurred at MCD28and annunciation46is warranted. In various embodiments, first gap G1and second gap G2may be disposed in series as shown inFIG.2B, or may be disposed in parallel in electric circuit34. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, in other embodiments, first gap G1and second gap G2may be of different sizes depending on the sizes of first chip42A and of second chip42B that are of interest.

During operation of MCD28shown inFIGS.2A and2Bwhen MCD28is immersed in lubricating fluid26, resistance value RV may be high (e.g., open circuit) when neither or only one of first gap G1and second gap G2is electrically bridged by first chip42A or second chip42B. On the other hand, resistance value RV may be low (e.g., short circuit, near 0 ohm) when first gap G1is electrically bridged by first chip42A, and second gap G2is electrically bridged by second chip42B. Accordingly, the chip detection at MCD28may be detected by way of a change in resistance value RV which may be determined at controller32. Upon detection of the change in resistance value RV that is indicative of a legitimate chip detection, controller32may initiate annunciation46which may alert a pilot of the aircraft and/or another interested party. Annunciation46may be visual (e.g., indicator light or message) or aural (e.g., tone or spoken message). It is understood that in some embodiments, controller32may be replaced by suitable analog circuitry that causes annunciation46upon first MCD terminal38A and third MCD terminal38C becoming electrically bridged by the presence of both first chip42A and second chip42B.

FIG.3Ais a schematic axial cross-section view of another exemplary multi-zone MCD128which may be part of chip detection system30of engine10, andFIG.3Bis a schematic representation of electric circuit134associated with MCD128. MCD128may have elements in common with MCD28described above and like elements are identified using like reference numerals. In contrast with MCD28, MCD128may include shunt resistor R1disposed in parallel with both first gap G1and second gap G2. MCD128may also include first capture zone36A, second capture zone36B, and optionally one or more additional capture zones to thereby reduce the probability of single-chip and/or fuzz-induced nuisance detections. First capture zone36A may include first MCD terminal38A spaced apart from second MCD terminal38B to define first gap G1therebetween. Second capture zone36B may include third MCD terminal38C spaced apart from second MCD terminal38B to define second gap G2therebetween. MCD128may be an axial disk-type magnetic chip detector. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, in other embodiments, first gap G1and second gap G2may be of different sizes depending on the size of first chip42A and of second chip42B that are of interest. In various embodiments, first gap G1and second gap G2may be disposed in series as shown inFIG.3B, or may be disposed in parallel in electric circuit134.

During operation of MCD128shown inFIGS.3A and3Bwhen MCD128is immersed in lubricating fluid26, resistance value RV may the value of R1(e.g., 2 k Ohm) when neither or only one of first gap G1and second gap G2is electrically bridged by first chip42A or second chip42B (shown inFIG.2A). On the other hand, resistance value RV may be low (e.g., short circuit, near 0 ohm) when first gap G1is electrically bridged by first chip42A, and second gap G2is electrically bridged by second chip42B. Accordingly, the chip detection at MCD128may be detected by way of a change in resistance value RV which may be determined at controller32. Upon detection of the change in resistance value RV that is indicative of a legitimate chip detection, controller32may initiate annunciation46which may alert a pilot of the aircraft and/or another interested party.

FIG.4Ais a schematic axial cross-section view of another exemplary multi-zone MCD228which may be part of chip detection system30of engine10, andFIG.4Bis a schematic representation of electric circuit234associated with MCD228. MCD228may have elements in common with other MCDs described above and like elements are identified using like reference numerals. In contrast with MCD128, MCD228may include shunt resistor R1disposed in parallel with first gap G1, and shunt resistor R2disposed in parallel with second gap G2. Resistor R1and resistor R2may have different or substantially identical resistance values. Resistor R1and resistor R2may be disposed in series with each other in electric circuit234.

MCD228may also include first capture zone36A, second capture zone36B, and optionally one or more additional capture zones. First capture zone36A may include first MCD terminal38A spaced apart from second MCD terminal38B to define first gap G1therebetween. Second capture zone36B may include third MCD terminal38C spaced apart from second MCD terminal38B to define second gap G2therebetween. MCD228may be an axial disk-type magnetic chip detector. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, as shown inFIGS.4A and4B, first gap G1may be larger than second gap G2so that G1>G2. First gap G1and second gap G2may be sized based on the size of first chip42A and second chip42B that are of interest. In various embodiments, first gap G1and second gap G2may be disposed in series as shown inFIG.4B, or may be disposed in parallel in electric circuit234.

During operation, the use of MCD228when MCD228is immersed in lubricating fluid26may allow to discriminate whether one or both of first capture zone36A and second capture zone36B is/are contaminated by metallic chips. For example, if resistor R1and resistor R2each have a resistance value of 2 k Ohms and none of first gap G1and second gap G2are electrically bridged by first chip42A or second chip42B (shown inFIG.2A), resistance value RV between first output terminal44A and second output terminal44B will be about 4 k Ohms. However, if one of first gap G1and second gap G2is electrically bridged by first chip42A or second chip42B, resistance value RV between first output terminal44A and second output terminal44B will be about 2 k Ohms. If both first gap G1and second gap G2are electrically bridged by first chip42A and second chip42B respectively, resistance value RV between first output terminal44A and second output terminal44B will be about 0 Ohms (i.e., short circuit).

The configuration of MCD228may also be used to identify which one(s) of first capture zone36A and second capture zone36B is/are contaminated by metallic chips by using different resistance values of first resistor R1and second resistor R2. This may be particularly useful if first gap G1and second gap G2are of different sizes and/or first capture zone36A and second capture zone36B are in different locations of lubrication system20. For example, if first resistor R1has a resistance value of 4 k Ohm and second resistor R2has a resistance value of 2 k Ohm, and none of first gap G1and second gap G2are electrically bridged by first chip42A or by second chip42B (shown inFIG.2A), resistance value RV between first output terminal44A and second output terminal44B will be about 6 k Ohms. However, if first gap G1is electrically bridged by first chip42A and second gap G2is not electrically bridged by second chip42B, resistance value RV between first output terminal44A and second output terminal44B will be about 2 k Ohms. If first gap G1is not electrically bridged by first chip42A and second gap G2is electrically bridged by second chip42B, resistance value RV between first output terminal44A and second output terminal44B will be about 4 k Ohms. If both first gap G1and second gap G2are electrically bridged by first chip42A and second chip42B respectively, resistance value RV between first output terminal44A and second output terminal44B will be about 0 Ohms (i.e., short circuit).

Controller32can then use the single resistance value RV to assess whether a small chip has been detected, a large chip has been detected, or if both first gap G1and second gap G2are electrically bridged by first chip42A and second chip42B respectively. This approach of discriminating between which capture zone(s) is causing the detection may be extended to MCDs of three or more detection zones.

In various embodiments disclosed herein, the single resistance value RV may provide a single and informative input to controller32and allow controller32to determine the state of MCD228. For example, resistance value RV may be the sole piece of information transferred from MCD228to controller32. Controller32may then use resistance value RV with one or more rules available to controller32to determine whether annunciation46is warranted. The rules may include actions associated with predetermined values for resistance value RV or predetermined ranges of values for resistance value RV. The rules and the multiple capture zones may be selected to provide a sensitivity suitable for providing legitimate chip detections and annunciations46.

The use of the single input may also facilitate integration of MCD228and other magnetic chip detectors disclosed herein with new or existing aircraft engines. For example, the retrofitting of MCD228into engine10may require little to no hardware modifications, but may require software modifications to apply rules and carry out desired actions based on resistance value RV.

FIG.5Ais a schematic axial cross-section view of another exemplary multi-zone MCD328which may be part of chip detection system30of engine10, andFIG.5Bis a schematic representation of electric circuit334associated with MCD328. MCD328may have elements in common with other MCDs described above and like elements are identified using like reference numerals. First capture zone36A of MCD328may include first MCD terminal38A spaced apart from second MCD terminal38B to define first gap G1therebetween. Second capture zone36B may include third MCD terminal38C spaced apart from second MCD terminal38B to define second gap G2therebetween. In various embodiments, first gap G1and second gap G2may be disposed in parallel as shown inFIGS.5A,5B, or may be disposed in series in electric circuit334. MCD328may be an axial disk-type magnetic chip detector. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, in other embodiments, first gap G1and second gap G2may be of different sizes depending on the size(s) of first chip42A and of second chip42B that are of interest. MCD328may include three or more capture zones defining respective gaps disposed in parallel or in series.

In contrast with MCD228, MCD328may include first shunt resistor R1disposed in series with first gap G1, second shunt resistor R2disposed in series with second gap G2, and third shunt resistor R3disposed in parallel with both first gap G1and second gap G2.

During operation of MCD328when MCD328is immersed in lubricating fluid26, the resultant resistance value RV may be indicative of which one(s) of first gap G1and second gap G2is/are electrically bridged by first chip42A and/or second chip42B based on which combination of first resistor R1, second resistor R2, third resistor R3, electrically bridged first gap G1, and electrically bridged second gap G2are reflected in resistance value RV. Accordingly, the chip detection at MCD328may be detected by way of a change in resistance value RV which may be determined at controller32. Upon detection of the change in resistance value RV that is indicative of a legitimate chip detection, controller32may initiate annunciation46which may alert a pilot of the aircraft and/or another interested party.

In various embodiments first capture zone36A and second capture zone36B may be in fluid communication with each other during operation. Alternatively, first capture zone36A and second capture zone36B may be fluidly sealed from each other and disposed in different fluid streams or in different fluid systems of engine10.

FIG.6Ais a schematic representation of another exemplary multi-zone MCD428of which may be part of chip detection system30of engine10, andFIG.6Bis a schematic representation of electric circuit434associated with MCD428. MCD428may have elements in common with other MCDs described above and like elements are identified using like reference numerals. First capture zone36A of MCD428may include first MCD terminal38A spaced apart from second MCD terminal38B to define first gap G1therebetween. Second capture zone36B may include third MCD terminal38C spaced apart from fourth MCD terminal38D to define second gap G2therebetween. In various embodiments, first gap G1and second gap G2may be disposed in series as shown inFIGS.6A,6B, or may be disposed in parallel in electric circuit434. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, in other embodiments, first gap G1and second gap G2may be of different sizes depending on the size(s) of first chip42A and of second chip42B that are of interest.

MCD428may be a combination of two or more single-zone axial disk-type magnetic chip detectors that are daisy chained together. For example, first capture zone36A may be provided by a first magnetic chip detector electrically integrated into electric circuit434via first connector C1, and second capture zone36B may be provided by a second magnetic chip detector electrically integrated into electric circuit434via second connector C2. In some installations, first capture zone36A and second capture zone36B may be in fluid communication with each other during operation. Alternatively, first capture zone36A and second capture zone36B may be fluidly sealed from each other and disposed in different fluid streams or in different fluid systems of engine10. The configuration of MCD428may permit the monitoring of different regions of lubrication system20using the single interface providing resistance value RV. The configuration of MCD428may permit a combination of different types of single-zone and/or multi-zone MCDs to be daisy chained together and provide a single output. For example, MCDs of different configurations (e.g., axial disk-type and prong type) and/or of different gap sizes may be combined together to meet requirements of the specific application.

MCD428may include first shunt resistor R1disposed in parallel with first gap G1, and second shunt resistor R2disposed in parallel with second gap G2.

During operation of MCD428when MCD428is immersed in lubricating fluid26, the resultant resistance value RV may be indicative of which one(s) of first gap G1and second gap G2is/are electrically bridged by first chip42A and/or second chip42B based on which combination of first resistor R1, second resistor R2, electrically bridged first gap G1, and electrically bridged second gap G2are reflected in resistance value RV.

FIG.7Ais a schematic representation of another exemplary multi-zone MCD528of which may be part of chip detection system30of engine10. MCD528may be a prong-type magnetic chip detector.FIG.7Bis a schematic axial end-on view of MCD528looking at MCD528along axis A inFIG.7A.FIG.7Cis a schematic representation of electric circuit534associated with MCD528ofFIG.7A. First capture zone536A of MCD528may include first MCD terminal538A spaced apart from second MCD terminal538B to define first gap G1therebetween. First MCD terminal538A may be a magnetic prong having properties of a magnet and having a north (N) polarity. Second MCD terminal538B may be a magnetic prong having properties of a magnet and having a south (S) polarity. Second capture zone536B may include third MCD terminal538C spaced apart from first MCD terminal538A to define second gap G2therebetween. Third MCD terminal538C may be a magnetic prong having properties of a magnet and having a south (S) polarity. As shown inFIG.7B, first MCD terminal538A, second MCD terminal538B, and third MCD terminal538C may be disposed in a triangular formation. A gap between two neighboring prongs of the same polarity such as between second MCD terminal538B and third MCD terminal538C, which are both south pole prongs, will not be a capture zone since the magnetic chips on prongs of the same polarity will repel each other.

In various embodiments, first gap G1and second gap G2may be disposed in series as shown inFIG.7Cor may be disposed in parallel in electric circuit534. In some embodiments, first gap G1and second gap G2may be of substantially the same size. However, in other embodiments, first gap G1and second gap G2may be of different sizes depending on the size(s) of first chip42A and of second chip42B that are of interest. MCD528may include first shunt resistor R1disposed in parallel with first gap G1, and second shunt resistor R2disposed in parallel with second gap G2.

During operation of MCD528when MCD528is immersed in lubricating fluid26, the resultant resistance value RV may be indicative of which one(s) of first gap G1and second gap G2is/are electrically bridged by first chip42A and/or second chip42B based on which combination of first resistor R1, second resistor R2, electrically bridged first gap G1, and electrically bridged second gap G2are reflected in resistance value RV between first output terminal544A and second output terminal544B.

FIG.8Ais a schematic axial end-on view of another exemplary multi-zone MCD628which may be part of chip detection system30of engine10.FIG.8Bis a schematic representation of electric circuit634associated with MCD628ofFIG.8A. First capture zone636A of MCD628may include first MCD terminal638A spaced apart from second MCD terminal638B to define first gap G1therebetween. First MCD terminal638A may be a magnetic prong having properties of a magnet and having a south (S) polarity. Second MCD terminal638B may be a magnetic prong having properties of a magnet and having a north (N) polarity. Second capture zone636B may include third MCD terminal638C spaced apart from first MCD terminal638A to define second gap G2therebetween. Third MCD terminal638C may be a magnetic prong having properties of a magnet and having a north (N) polarity. Third capture zone636C may include third MCD terminal638C spaced apart from fourth MCD terminal638D to define third gap G3therebetween. Fourth MCD terminal638D may be a magnetic prong having properties of a magnet and having a south (S) polarity. As shown inFIG.8A, first MCD terminal638A, second MCD terminal638B, third MCD terminal638C, and fourth MCD terminal638D may be disposed in a rectangular or square formation. A gap between two neighboring prongs of the same polarity will not be a capture zone since the magnetic chips on prongs of the same polarity will repel each other.

In various embodiments, first gap G1, second gap G2, and third gap G3may be disposed in series as shown inFIG.8B, or may be disposed in parallel in electric circuit634. In some embodiments, first gap G1, second gap G2, and third gap G3may be of substantially the same size. However, in other embodiments, first gap G1, second gap G2, and third gap G3may be of different sizes depending on the size(s) of chips that are of interest. For example, second gap G2may be larger than first gap G1and also larger than third gap G3as shown inFIG.8B. MCD628may include first shunt resistor R1disposed in parallel with first gap G1, second shunt resistor R2disposed in parallel with second gap G2, and third shunt resistor R3disposed in parallel with third gap G3.

During operation of MCD628when MCD628is immersed in lubricating fluid26, the resultant resistance value RV may be indicative of which one(s) of first gap G1, second gap G2, and third gap G3is/are electrically bridged by chips based on which combination of first resistor R1, second resistor R2, third resistor R3, electrically bridged first gap G1, electrically bridged second gap G2, and electrically bridged third gap G3are reflected in resistance value RV between first output terminal644A and second output terminal644B.

FIG.9Ais a schematic axial end-on view of another exemplary multi-zone MCD728which may be part of chip detection system30of engine10.FIG.9Bis a schematic representation of electric circuit734associated with MCD728ofFIG.9A. First capture zone736A of MCD728may include first MCD terminal738A spaced apart from second MCD terminal738B to define first gap G1therebetween. First MCD terminal738A may be a magnetic prong having properties of a magnet and having a north (N) polarity. Second MCD terminal738B may be a magnetic prong having properties of a magnet and having a south (S) polarity. Second capture zone736B may include third MCD terminal738C spaced apart from second MCD terminal738B to define second gap G2therebetween. Third MCD terminal738C may be a magnetic prong having properties of a magnet and having a north (N) polarity. Third capture zone736C may include third MCD terminal738C spaced apart from fourth MCD terminal738D to define third gap G3therebetween. Fourth MCD terminal738D may be a magnetic prong having properties of a magnet and having a south (S) polarity. Fourth capture zone736D may include first MCD terminal738A spaced apart from fourth MCD terminal738D to define fourth gap G4therebetween. As shown inFIG.9A, first MCD terminal738A, second MCD terminal738B, third MCD terminal738C, and fourth MCD terminal738D may be disposed in a rectangular or square formation.

In some embodiments, first gap G1and fourth gap G4may be disposed in series, and second gap G2and third gap G3may be disposed in series in electric circuit734. A first branch including first gap G1and fourth gap G4may be disposed in parallel with a second branch including second gap G2and third gap G3. In some embodiments, first gap G1, second gap G2, third gap G3and fourth gap G4may be of substantially the same size. However, in other embodiments, first gap G1, second gap G2, third gap G3, and fourth gap G4may be of different sizes depending on the size(s) of chips that are of interest. MCD728may include first shunt resistor R1disposed in parallel with first gap G1, second shunt resistor R2disposed in parallel with second gap G2, third shunt resistor R3disposed in parallel with third gap G3, and fourth shunt resistor R4disposed in parallel with fourth gap G4. In some embodiments, first resistor R1, second resistor R2, third resistor R3, and fourth resistor R4may be connected in a Wheatstone bridge configuration.

During operation of MCD728when MCD728is immersed in lubricating fluid26, the resultant resistance value RV between first output terminal744A and second output terminal744B may be near 0 Ohms (i.e., short circuit) when two or three of first gap G1, second gap G2, third gap G3, and fourth gap G4are electrically bridged by metallic chips.

FIG.10is a flow diagram of method100of detecting metallic chips in engine fluid of an engine. Method100may be performed using MCD28,128,228,328,428,528,628,728described herein or using another MCD. Aspects of method100may be combined with other methods or steps described herein. Method100may also include aspects of system30and of MCD28,128,228,328,428,528,628,728. In various embodiments, method100may include:when the magnetic chip detector (e.g., MCD28,128,228,328,428,528,628,728) is immersed in engine fluid (e.g., lubricating fluid26), receiving one or more metallic chips (e.g.,42A,42B) in one or both of the first magnetic chip capture zone and the second magnetic chip capture zone (block102); andusing an electric circuit (e.g., electric circuit34,134,234,334,434,534,634,734) including both the first magnetic chip capture zone and the second magnetic chip capture zone, generating an output indicative of a chip detection in the one or both of the first magnetic chip capture zone and the second magnetic capture zone (block104).

In some embodiments of method100, the output may be indicative of which of the first magnetic chip capture zone, the second magnetic capture zone, or optionally one or more additional magnetic chip capture zones is/are associated with the chip detection. In some embodiments of method100, the first magnetic chip capture zone and the second magnetic chip capture zone may be in fluid communication with each other when receiving one or more metallic chips in one or both of the first magnetic chip capture zone and the second magnetic chip capture zone.

The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology.