MARINE PROPULSION SYSTEM, METHOD FOR MONITORING A MARINE PROPULSION SYSTEM, AND MARINE VESSEL COMPRISING SUCH MARINE PROPULSION SYSTEM

TECHNICAL FIELD

[0001] This disclosure relates generally to marine propulsions systems. In particular aspects, the disclosure relates to a marine propulsion system comprising a self-balancing propeller system, to a method for monitoring a marine propulsion system comprising a selfbalancing propeller system, and to a marine vessel comprising such marine propulsion system.

[0002] As it will be readily appreciated from the following, the disclosure can be applied in principle with any type of marine vessels, be them newly introduced in service or already in operations, and therefore is not restricted to any particular marine vessel.

BACKGROUND

[0003] In marine applications, the use of propulsion systems comprising two propellers, usually indicated as a front propeller and a rear propeller, is well known.

[0004] The two propellers are operatively associated to an input shaft operated by a driving motor, and are interconnected to each other by a planetary gear system in such a way that they rotate in opposite directions and forms a substantially self-balanced propeller system.

[0005] Clearly, for an efficient and effective operation of a marine vessel, the correct operation of the propulsion system, and in particular of the rotating propellers, is of outmost importance. Indeed, if for instance one of the two propellers would not work according to the optimal specifications designed for it, not only the performance of the relevant propeller may be impacted, but also the whole propulsion system may be negatively affected.

SUMMARY

[0006] Hence, there is room and desire for improving operations of marine propulsion systems, and in particular as regard to identifying, as early as possible, when any of the propellers used in the marine propulsion system is not working according to the expected conditions.

[0007] To this end, according to an aspect of the disclosure, there is provided a marine propulsion system comprising:

- at least one driving machine;

- an input shaft which is suitable to be rotated by the at least one driving machine;

- a first propeller operatively connected to the input shaft;

- a second propeller which is operatively interconnected to the first propeller by means of a differential planetary gear system;

- a sensor arrangement which provides signals indicative of the rotational speed of at least one of the first and second propellers;

- a controller that calculates, based on the signals received from the sensor arrangement, the actual rotational speed of at least one of the first and second propellers, and determines an actual operative condition of the propulsion system based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers.

[0008] In one example, the controller determines the actual operative condition of the propulsion system based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers and on a predetermined or currently measured value of the rotational speed of the input shaft.

[0009] In one example, the sensor arrangement provides signals indicative of the rotational speed of both the first and second propellers.

[0010] In another example, the sensor arrangement comprises a unique sensor unit arranged to output signals indicative of the rotational speeds of both said first and second propellers.

[0011] In a further example, the unique sensor unit is arranged to output signals indicative of the differential rotational speed between said first and second propellers.

[0012] In yet a further example, the sensor arrangement comprises a first sensor unit which provides first signals indicative of the rotational speed of the first propeller and a second sensor unit which provides second signals indicative of the rotational speed of the second propeller.

[0013] In a possible example, the sensor arrangement comprises a first sensor unit which provides first signals indicative of the rotational speed of the first propeller and a second sensor unit which provides second signals indicative of the actual rotational speed of the input shaft.

[0014] In another example, the sensor arrangement comprises a first sensor unit which provides first signals indicative of the rotational speed of the first propeller, a second sensor unit which provides second signals indicative of the actual rotational speed of the second propeller, and a third sensor unit which provides third signals indicative of the actual rotational speed of the input shaft.

[0015] In a further example, the controller generates an alert if a value of the rotational speed calculated for at least one of the first and second propellers exceeds a predefined threshold value or range.

[0016] In yet another example, the controller keeps the actual value of the rotating speed of the input shaft substantially constant at the corresponding operating rotating speed desired.

[0017] According to another aspect of the disclosure, there is provided a marine vessel comprising a marine propulsion system as above defined, and in particular as defined in the relevant appended claims.

[0018] According to a further aspect of the disclosure, there is provided a method for monition a marine propulsion system comprising an input shaft which is suitable to be rotated by at least one driving machine, a first propeller operatively connected to the input shaft, and a second propeller which is operatively interconnected to the first propeller by means of a differential planetary gear system, whereon the method comprises:

- providing, via a sensor arrangement, signals indicative of the rotational speed of at least one of the first and second propellers;

- calculating, via a controller, based on the signals received from the sensor arrangement, the actual rotational speed of at least one of the first and second propellers; and

- determining an actual operative condition of the propulsion system based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers.

[0019] In one possible example, said determining comprises determining the actual operative condition of the propulsion system based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers and on a predetermined or currently measured value of the rotational speed of the input shaft. [0020] In another possible example, the method further comprises generating an alert if a value of the rotational speed calculated for at least one of the first and second propellers exceeds a predefined threshold value or range.

[0021] In practice, according to the disclosure, the controller is able, based on the values calculated for the rotational speed(s) to identify as early as possible, if the propeller system, and in particular at least one of the two propellers, is not properly functioning and may be affected by any damaged or malfunctioning part(s).

[0022] Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the disclosure as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] With reference to the appended drawings, below follows a more detailed description of aspects of the disclosure cited as examples.

[0024] FIG. 1 is a view illustrating an exemplary marine propulsion system according to one example of the disclosure.

[0025] FIG. 2 is a flowchart illustrating an exemplary method for monitoring a marine propulsion system according to one example of the disclosure.

DETAILED DESCRIPTION

[0026] Aspects set forth below represent the necessary information to enable those skilled in the art to practice the disclosure.

[0027] It should be noted that in order to clearly and concisely describe the present disclosure, the drawings may not necessarily be to scale and certain features of the disclosure may be shown in somewhat schematic form.

[0028] Further, the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0029] It will be also understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0030] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled", “operatively connected” or “operatively coupled”, to another element, it can be directly connected or coupled to the other element, or intervening elements may be present, or that there may be a functional coupling there between, namely an action of an element, such as a displacement, a rotation et cetera, may trigger or result in an action of the other element operatively coupled therewith. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0031] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0032] In particular, when the term "adapted" or "arranged" or "configured" or "shaped", or any similar/equivalent term is used herein while referring to any component as a whole, or to any part of a component, or to a combination of components, it has to be understood that it means and encompasses correspondingly either the structure, and/or configuration and/or form and/or positioning of the related component or part thereof, or combinations, such term refers to.

[0033] For instance, for electronic and/or software means, each of the above listed terms means and encompasses electronic circuits or parts thereof, as well as stored, embedded or running software codes and/or routines, algorithms, or complete programs, suitably designed for achieving the technical results and/or the functional performances for which such means are devised within the context of the present disclosure.

[0034] In addition, when the term “about” or “substantial” or “substantially” is used herein, it has to be understood as encompassing an actual variation of plus or minus 5% with respect to a reference value.

[0035] Finally, in the following description and claims, the numeral ordinals first, second, third et cetera..., will be used only for the sake of clarity of description and in no way they should be understood as limiting for whatsoever reason; in particular, the indication of a component referred to for instance as the “third sensor unit...” does not imply necessarily the presence or strict need of the preceding “first” and/or “second” ones, nor that the order should be the one described in the illustrated exemplary embodiment(s). Indeed, as it will become more apparent from the following description, according to possible examples, there could be only one sensor unit, or a first and a third sensor units, or a second and a third sensor units, et cetera.

[0036] FIG. 1 schematically illustrates a marine propulsion system according to one example, therein indicated by the overall reference number 100.

[0037] As illustrated, the exemplary marine propulsion system 100 comprises:

- at least one driving machine 1 ;

- an input shaft 3 which is suitable to be connected to and rotated by the at least one driving machine 1;

- a first propeller 5 connected to the input shaft 3;

- a second propeller 7 which is connected to the first propeller 1 by means of a differential planetary gear system 9;

- a sensor arrangement 10 arranged to provide signals S _rs indicative of the actual rotational speed of at least one of the first and second propellers 5 and 7.

[0038] As illustrated in the exemplary embodiment of FIG. 1 the second propeller 7 is for example fixed at the rear end of a shaft 8 which is connected to and driven by the input shaft 3.

[0039] As it occurs often, the first and second propellers 5 and 7 can be mounted on output shaft(s). [0040] The input shaft 3 is also connected to the driving machine 1, for example via a bevel gear and an axle, schematically represented in figure 1 by the reference numbers 2 and 4, respectively.

[0041] Clearly, the illustrated connection between the input shaft 3 and the driving machine 1 has to be understood as a mere possible example and can be realized in any other suitable manner.

[0042] In one example, the at least one driving machine 1 comprises or is constituted by an electric engine.

[0043] According to the example illustrated in FIG. 1, the first propeller 5 is positioned in front of the second propeller 7 along the shaft 8, and in particular is mounted on a hub 6 positioned, for at least a portion thereof, around the shaft 8.

[0044] The second propeller 7 is connected to the first propeller 1 by means of a differential planetary gear system, schematically indicated in figure 1 by the reference number 9, which is positioned for instance inside the hub 6.

[0045] As those skilled in the art can appreciate, the ways in which the input shaft 3 is connected to the shaft 8, the first propeller 5 is mounted on the hub 6, the hub 6 is mounted around the shaft 8, the second propeller 7 is mounted on the shaft 8, the planetary gear system 9 is configured and the way it operatively interconnects the first and second propellers 5 and 7, can be realized according to solutions known or readily available to those skilled in the art, and therefore not described herein in details.

[0046] Conveniently, the marine propulsion system 100 according to the disclosure, comprises a controller 20 that is configured to calculate, based on the signals S _rs received from the sensor arrangement 10, the actual rotational speed of at least one of the first and second propellers 5 and 7, and then to determine an actual operative condition of the propulsion system 100 based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers 5 and 7.

[0047] In practice, according to the disclosure, the controller 20 is capable, by determining values of the rotating speed, of verifying if the propulsion system 100, and in particular the two propellers 5, 7 are operating properly, i.e. under normal or in any case acceptable operating conditions or not.

[0048] In one example, the controller 20 is configured to generate an alert SA if a value of the rotational speed of at least one of, in particular both, the propellers 5, 7 exceeds a predefined threshold value or range. [0049] The alert SA can be of any suitable type, for example a warning signal sent for instance to a control display on board of the vessel on which the system 100 is installed, it can be a signal turning on a warning light in a control panel, et cetera.

[0050] In this way, propellers running out of the designed performances can be timely identified, thus preventing for instance variable transmission reduction ratio and aliasing of propeller torsional vibrations.

[0051] The controller 20 can comprise or be constituted by any processor-based device, e.g. a microprocessor, microcontroller, a microcomputer, a programmable logic controller, an application specific integrated circuit, or any other programmable circuit. Therefore, the term processor, as used herein, is not limited to just those integrated circuits referred to in the art as computers, but broadly refers to microprocessors, microcontrollers, microcomputers, programmable logic controllers, application specific integrated circuits, and other programmable circuits, and these terms are used interchangeably herein. In addition, the controller 20 may further include or be coupled to: a storage unit or repository, e. g. a memory, such as a non-transitory computer-readable storage medium, for storing for instance software code to be executed while performing the tasks devised for the controller within the context of the present disclosure, data, et cetera; a communication module, for example for communicating with the sensor arrangement 10. The controller 20 can be for instance any suitable processor-based device of a type commercially available, suitably programmed and provided to the extent necessary with circuitry, in order to perform the functionalities devised for it according to the present disclosure.

[0052] For the sake of ease of illustration, in FIG. 1 the controller 20 is represented inside the pod part of a marine vessel on board of which the system 100 according to the disclosure can be installed; clearly, the controller 20 can be positioned in any suitable or desired position, even remotely from the marine vessel is desired.

[0053] According to one possible example, the controller 20 is usefully configured to determine the actual operative condition of the propulsion system 100 based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers 5 and 7, and on a predetermined or currently measured value of the rotational speed of the input shaft 3.

[0054] In particular, the rotational speed of the input shaft 3 is usually known, i.e. predetermined by, or anyhow known to, the control unit of the driving machine 1. [0055] This control unit may coincide with or be part of the controller 20. Alternatively, it can be a separated unit which is in operative communication with the controller 20 and can provide to it the value(s) of the rotating speed of the input shaft 3.

[0056] Alternatively, if for whatever reason the value of the rotating speed of the input shaft 3 is not predetermined or anyhow known, or if it is desired for example to have an actual detection to determine its current value in real time, and/or to have a certain redundancy, then the sensor arrangement 10 according to the disclosure can be suitably configured to provide the controller 20 with signals indicative of the current value of the rotational speed of the input shaft 3. Then, the controller 20 can measure such rotational speed of the input shaft 3 based on the signals received.

[0057] In one example, the controller 20 is configured to keep the actual value of the rotating speed of the input shaft 3 substantially constant at a corresponding operating rotating speed desired. Hence, if the vessel on which the propulsion system 100 is installed is proceeding at a certain first speed and the input shaft 3 has to rotate at a corresponding first rotating speed, then the controller 20 monitors and controls the input shaft 3 to make it rotate at a substantially constant first rotating speed. Likewise, if the vessel is proceeding at a certain second speed and the input shaft 3 has to rotate at a corresponding second rotating speed, then the controller 20 monitors and controls the input shaft 3 to make it rotate at a substantially constant second rotating speed.

[0058] In one possible aspect, the sensor arrangement 10 provides signals S _rs indicative of the rotational speed of both the first and second propellers 5 and 7.

[0059] Depending on the applications, the sensor arrangement 10 may comprise a different number/type of sensors or sensors units.

[0060] In one possible example, the sensor arrangement 10 comprises only one sensor unit, schematically represented in figure 1 by the dotted-line box 14, which is arranged to output signals indicative of the rotational speeds of both the first and second propellers 5, 7. [0061] In one possible example, the unique sensor unit 14 is in particular arranged to output signals indicative of the differential rotational speed between the first and second propellers 5 and 7.

[0062] In a further example, the sensor arrangement 10 comprises a first sensor unit, schematically represented in figure 1 by the reference number 11, which provides first signals indicative of the rotational speed of the first propeller 5 and a second sensor unit, schematically represented in figure 1 by the reference number 12, which provides second signals indicative of the rotational speed of the second propeller 7.

[0063] In another possible example, the sensor arrangement 10 comprises a first sensor unit 11 which provides first signals indicative of the rotational speed of one of the propellers, for example the first propeller 5, and a second sensor unit, schematically represented in figure 1 by the reference number 13, which provides second signals indicative of the actual rotational speed of the input shaft 3. Alternatively, according to this example, the first sensor unit 11 can be associated to and provide first signals indicative of the rotational speed of the second propeller 7.

[0064] According to yet another example, the sensor arrangement 10 comprises a first sensor unit 11 which provides first signals indicative of the rotational speed of the first propeller 5, a second sensor unit 12 which provides second signals indicative of the actual rotational speed of the second propeller 7, and a third sensor unit 13 which provides third signals indicative of the actual rotational speed of the input shaft 3.

[0065] The or each of the sensor units 11, 12, 13 and 14, can comprise or be constituted by any sensor suitable to detect and provide the signals Sirs indicative of the rotational speed detected, e.g. a Hall effect sensor.

[0066] In one possible example, if two or more sensing units are used, then it is possible to use also sensors of different types.

[0067] FIG. 2 is a flow chart schematically illustrating one example of a method, indicated by the overall reference number 200, for monitoring a marine propulsion system, i.e. the marine propulsion system 100 as above described.

[0068] The method 200 can be carried out by means of the components of the marine propulsion system 100 above described.

[0069] In any case, the operational steps described in any of the exemplary aspects herein are described to provide examples and discussion. The steps may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the steps, or may be performed by a combination of hardware and software. Although a specific order of method steps may be shown or described, the order of the steps may differ. In addition, two or more steps may be performed concurrently or with partial concurrence.

[0070] As illustrated in FIG. 2, the method 200 comprises the following steps: - 210: providing, for example via a sensor arrangement 10, signals S _sr indicative of the rotational speed of at least one of first and second propellers 5 and 7 ;

- 220: calculating, for example via a controller 20, based on the signals S _rs received from the sensor arrangement 10, the actual rotational speed of at least one of the first and second propellers 5 and 7 ; and

- 230: determining an actual operative condition of the propulsion system 100 based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers 5 and 7.

[0071] In one example, the step 230 of determining comprises determining the actual operative condition of the propulsion system 100 based at least on the values of the actual rotational speed calculated for at least one of the first and second propellers 5 and 7, and on a predetermined or currently measured value of the rotational speed of the input shaft 3.

[0072] In one example, the method 200 further comprises a step 240 of generating an alert SA if a value of the rotational speed calculated for at least one of the first and second propellers 5, 7, exceeds a predefined threshold value or range.

[0073] In particular, the alert signal alert SA is generated if one or more values of the rotational speed calculated for both propellers 5, 7 exceed a predefined threshold value or range

[0074] Hence, it is evident from the foregoing description that, according to the present disclosure, it is possible to properly monitor and timely identify if the propeller system is not working correctly. In this way, operators are given the possibility to intervene as early as possible, thus mitigating the possible occurrence and/or duration of inefficient operations, as well as reducing the likelihood of worsening incumbent damages.

[0075] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the inventive concepts being set forth in the following claims.