Method for determining the effect of changes in propulsion characteristics on the performance of a marine propulsion system - Patents.com

Abstract

A method is disclosed for determining an effect of a change in a propeller characteristic on the performance of a marine vessel propeller, the method including obtaining information indicative of a performance characteristic of a first propeller of the marine vessel based on operation of the first propeller with a first change in the propeller characteristic during a first time period, obtaining information indicative of a performance characteristic of a second propeller of the marine vessel based on operation of the second propeller with a second change in the propeller characteristic during the first time period concurrently with the first propeller, the second change being different from the first change, and determining a difference between the performance characteristic of the first propeller and the performance characteristic of the second propeller. An apparatus and a non-transitory computer readable storage medium for determining the effect of a change in the propeller characteristic are also disclosed.

Description

[Technical field]

[0001] The present invention relates to a method for determining the effect of changes in propeller characteristics on the performance of a marine vessel propeller, an apparatus for determining the effect of changes in propeller characteristics on the performance of a marine vessel propeller, a method for determining performance characteristics of a marine vessel propeller, an apparatus for determining performance characteristics of a marine vessel propeller, a non-transitory computer readable storage medium, and a marine vessel equipped with such an apparatus and / or a non-transitory computer readable storage medium. [Background technology]

[0002] The operation of a marine propulsion system (e.g., an internal combustion engine) is affected by propulsion system characteristics. For example, the fuel efficiency of a marine internal combustion engine depends on various characteristics, such as the type of lubricant supplied to the engine during operation and the type of fuel supplied to the engine during operation.

[0003] There is a need to be able to accurately determine the effect of changes in propeller characteristics on propeller performance at sea so that beneficial propeller characteristics can be identified and employed to improve propeller performance. Summary of the Invention

[0004] According to a first aspect of the present invention there is provided a method for identifying an effect of a change in a propeller characteristic on the performance of a marine vessel propeller, the method comprising obtaining information indicative of performance characteristics of a first propeller of the marine vessel based on operation of the first propeller with a first change in the propeller characteristic, during a first time period; obtaining information indicative of performance characteristics of a second propeller of the marine vessel based on operation of the second propeller with a second change in the propeller characteristic, during the first time period concurrently with the first propeller, where the second change is different from the first change; and identifying a difference between the performance characteristics of the first propeller and the performance characteristics of the second propeller.

[0005] Advantageously, operating two propellers with varying propeller characteristics simultaneously on the same vessel allows for a more accurate comparison of propeller performance across the variations in propeller characteristics. For example, operating both propellers simultaneously on the same vessel means that both propellers are exposed to the same external conditions (e.g., factors that affect the vessel as a whole, including weather-based and time-based variations such as wind direction, wind speed, humidity, and temperature) during the test period. Thus, observed differences in propeller performance characteristics between engines operating simultaneously on the same vessel may be more accurately attributed to predetermined differences between the propeller characteristic variations, rather than to factors external to the vessel.

[0006] In contrast, investigating the effects of propeller characteristics by operating a single propeller with a first propeller characteristic for a first period and then varying the propeller characteristics of the single propeller for a second period means that external factors on the operation of the propeller itself (e.g., weather-based and time-based changes in wind direction, wind speed, humidity, air temperature, sea temperature, wave conditions, ocean conditions, etc.) may change between the two test periods, meaning that a direct comparison of the results cannot accurately quantify the effects resulting from the change in propeller characteristics.

[0007] Furthermore, obtaining information indicative of propeller performance characteristics based on operation of a vessel's propeller in accordance with the present method may be indicative of propeller performance characteristics replicated upon further operation of the propeller in other vessels at sea, rather than the results of a study in which propeller characteristics of the propeller were varied in a laboratory environment on land, for example.

[0008] A laboratory study may typically involve operating a propeller with a first propeller characteristic for a first period of time and then varying the propeller characteristic for a second period of time. However, propellers used in a laboratory environment are typically smaller than propellers used on ships, such as marine vessels. Laboratory micropropellers often have different thermodynamics. For example, laboratory micropropellers are not connected to a propeller that experiences resistance from water during operation on a ship, and / or laboratory micropropellers are not typically exposed to the physical conditions, such as temperature and pressure, of a propeller mounted on a ship at sea. Furthermore, laboratory propellers are often simplified and are not connected to the associated auxiliary equipment typically present on a ship. Thus, the quantification of the effect resulting from the change in propeller characteristic by the present method typically more accurately indicates the effect of the change in propeller characteristic on a ship at sea than the corresponding quantification determined in a laboratory environment.

[0009] Optionally, the method further includes identifying a difference between the performance characteristic of the first propeller and the performance characteristic of the second propeller as being attributable to a difference between the first change in the propeller characteristic and the second change in the propeller characteristic.

[0010] For example, the difference between a first change in a propeller characteristic and a second change in a propeller characteristic may be the only controllable variable that differs between operation of the first propeller and operation of the second propeller, in which case an identified difference between a performance characteristic of the first propeller and a performance characteristic of the second propeller may be more accurately identified as being due to the difference between the first change and the second change.

[0011] Advantageously, by identifying that the difference in performance characteristics is due to a difference between the first change in the propeller characteristic and the second change in the propeller characteristic, a marine operator may be able to identify modifications to the operation of the propeller(s) on the marine vessel that improve the performance characteristics of the propeller(s) on the marine vessel.

[0012] Optionally, the method further includes obtaining information indicative of performance characteristics of a first propeller of the marine vessel based on operation of the first propeller with a second change in the propeller characteristic during a second time period, obtaining information indicative of performance characteristics of a second propeller of the marine vessel based on operation of the second propeller with the first change in the propeller characteristic during the second time period simultaneously with the first propeller, and identifying a difference between the performance characteristics of the first propeller during the second time period and the performance characteristics of the second propeller during the second time period.

[0013] For example, the change in the propeller characteristics is switched between the propellers during the second time period. Advantageously, by switching the change in the propeller characteristics between the propellers during the second time period, artifacts may be at least partially reduced when identifying differences in performance characteristics resulting from existing differences between the first and second propellers.

[0014] Optionally, the method further comprises determining a representative (eg, average) value of a difference between the performance characteristic during the first time period and the performance characteristic during the second time period.

[0015] Optionally, the method further includes obtaining information indicative of (e.g., identifying) performance characteristics of a first propeller of the vessel based on operation of the first propeller due to a first change in the propeller characteristic during a third time period, obtaining information indicative of (e.g., identifying) performance characteristics of a second propeller of the vessel based on operation of the second propeller due to a second change in the propeller characteristic during the third time period simultaneously with the first propeller, and identifying a difference between the performance characteristics of the first propeller during the third time period and the performance characteristics of the second propeller during the third time period.

[0016] For example, the test conditions of a first period are repeated for a third period. Advantageously, by implementing a so-called "ABA" testing protocol, artifacts are reduced (e.g., eliminated) in identifying differences in performance characteristics resulting from differences in propeller characteristics that are beyond the control of the operator (e.g., various wear conditions of the propeller and / or existing conditions of the propeller components, such as clearances between components that are beyond the control of the operator).

[0017] Optionally, the method further includes determining a representative (e.g., average) value of a difference between the performance characteristic during the first time period, the performance characteristic during the second time period, and the performance characteristic during the third time period.

[0018] Optionally, the duration of the first time period is the same as the duration of the second time period. Optionally, the duration of the third time period is the same as the duration of the first time period and / or the duration of the second time period. Advantageously, having the periods of equal duration may mean that a similar number of data points are obtained in each time period, improving comparisons between periods.

[0019] Optionally, identifying a difference between the performance characteristic of the first thruster and the performance characteristic of the second thruster includes performing a statistical analysis of the information indicative of the performance characteristic of the first thruster and the information indicative of the performance characteristic of the second thruster.

[0020] Optionally, performing the statistical analysis includes determining normality of the information indicative of the performance characteristics, e.g., determining the extent to which the information is drawn from a normally distributed population. For example, performing the statistical analysis includes performing a statistical normality test of the variables and residuals. In an embodiment, the statistical normality test is one or more of a Kolmogorov test, a Shapiro test, or an Anderson-Darling test. In an embodiment, the statistical normality test is a Shapiro test.

[0021] Optionally, performing the statistical analysis includes determining homogeneity of variance of the information indicative of the performance characteristic, e.g., determining the extent to which residual variances are homogeneous. For example, performing the statistical analysis includes performing a homogeneity of variance test. In an embodiment, the homogeneity of variance test is a Breuscher test or a Levene test. In an embodiment, the homogeneity of variance test is a Levene test.

[0022] Optionally, performing the statistical analysis includes determining the statistical significance of the identified differences between the performance characteristics. In an embodiment, determining the statistical significance includes performing an independent samples t-test.

[0023] Advantageously, performing a statistical analysis may increase the accuracy of the difference identified between the performance characteristics of the first and second thrusters, for example, in an embodiment of the method in which identifying the difference between the performance characteristics includes performing a statistical analysis, a statistically significant difference to an accuracy of 0.5% or an accuracy of 0.1% may be identified.

[0024] As used herein, a "propulsor" refers to a device that, during operation, provides propulsive force to the marine vessel or powers another component that provides propulsive force to the marine vessel. Optionally, each propulsor includes a motor, the motor configured to power one or more propellers of the marine vessel during operation.

[0025] Optionally, each of the propulsors is an internal combustion engine. Optionally, each of the internal combustion engines is a two-stroke engine, such as a marine two-stroke engine. In an embodiment, each of the internal combustion engines is a marine two-stroke crosshead engine.

[0026] Optionally, each of the propulsors is an electric motor. Optionally, the electric motors are configured to receive power from a fuel cell.

[0027] The method includes identifying a difference between a performance characteristic of the first thruster and a performance characteristic of the second thruster. Optionally, the performance characteristic is thruster efficiency.

[0028] Optionally, the performance characteristic is airborne emission(s) from the propeller. For example, the method allows to identify the effect of a change in propeller characteristics on the airborne emission(s) of the propeller. In an embodiment, the performance characteristic is airborne emission(s)-fuel efficiency (e.g., the ratio of the mass of emissions emitted from the propeller during operation of the propeller during a period of time to the mass of fuel consumed during operation of the propeller during the period of time at a given engine load), or airborne emission(s) efficiency (e.g., the ratio of the mass of emissions emitted from the propeller during operation of the propeller during a period of time to the power output of the propeller during the period of time), or total airborne emission(s) (e.g., the mass of exhaust(s) emitted from the propeller during operation of the propeller during a period of time). Advantageously, the performance characteristic being airborne emission(s) may mean that the operator can identify changes during operation of the vessel that will reduce the airborne emissions from the vessel.

[0029] Optionally, the propeller performance characteristics are filter smoke number, CO emissions, CO2 emissions, NO x emissions, SO x emissions, VOC emissions, particulate matter, or THC emissions.

[0030] Optionally, the performance characteristic is energy conversion efficiency. For example, the method allows to identify the effect of changes in propeller characteristics on the energy conversion efficiency of the propeller. In the present context, "energy conversion efficiency" refers to the ratio of the energy consumed by the propeller during operation (e.g. chemical potential energy supplied to the propeller, or electrical energy supplied to the propeller) to the energy output of the propeller (e.g. work done when rotating a power shaft). Advantageously, the performance characteristic being energy conversion efficiency may mean that a vessel operator can identify changes that improve the operating efficiency of the vessel.

[0031] Optionally, energy is provided to the propeller in the form of chemical potential energy, and the propeller consumes fuel to provide thrust. Optionally, the performance characteristic is fuel efficiency. For example, the method allows for identifying the effect of changes in propeller characteristics on the fuel efficiency of the propeller. In the present context, "fuel efficiency" refers to the ratio of the mass of fuel consumed by the engine over an operating period to the power output of the engine, which may be expressed in grams per kilowatt-hour (g / kWh). In an embodiment, the performance characteristic is the "Specific Fuel Oil Consumption" (SFOC) of the engine.

[0032] The method includes determining an effect of a change in a propeller characteristic on the performance of the marine propeller. As used herein, a "propeller characteristic" is an operating factor of the propeller that can cause a predetermined change. For example, a propeller characteristic is an operating factor of the propeller that can be controlled (at least in part) by an operator of the propeller. Optionally, the propeller characteristic relates to a fluid within the propeller, a component of the propeller, an operating parameter of the propeller, a component of a propeller auxiliary, or an operating parameter of a propeller auxiliary.

[0033] Optionally, the propeller characteristics are one or more of the following: physicochemical characteristics of the fuel supplied to the propeller, physicochemical characteristics of the lubricant (e.g., lubricating oil) supplied to the propeller, the amount of lubricant delivered to the propeller, the tuning of the propeller, the material of the propeller components, the shape / size of the propeller components, the surface topography of the propeller components, the arrangement of the propeller components, the fuel delivery method, the lubricant delivery method, the configuration of the propeller ancillary equipment (e.g., turbocharger(s), cooling system(s)), the exhaust gas treatment method, or the particulate filter. Advantageously, these examples of propeller characteristics may be at least partially controlled by the propeller operator and / or the vessel owner.

[0034] Optionally, each propeller is an internal combustion engine and the propeller characteristics are one or more of: physicochemical characteristics of a fuel supplied to the propeller, physicochemical characteristics of a lubricant (e.g., lubricating oil) supplied to the propeller, an amount of lubricant delivered to the internal combustion engine, engine tuning, materials of engine components, shapes / sizes of engine components, surface topography of engine components, arrangement of engine components, fuel delivery method, lubricant delivery method, configuration of engine ancillary equipment (e.g., turbocharger(s), cooling system(s)), exhaust gas treatment method, or particulate filters.

[0035] Optionally, the propulsion characteristic is a physicochemical characteristic of a fuel or a physicochemical characteristic of a lubricant.

[0036] Examples of physicochemical characteristics of the fuel include the sulfur content of the fuel, the composition and proportion of hydrocarbons in the fuel (e.g., chain length), the cetane number of the fuel, additives in the fuel, the heating value of the fuel, the kinematic viscosity of the fuel, the density of the fuel, the atomization of the fuel upon delivery to the propeller, the temperature of the fuel upon delivery to the propeller, and the pressure of the fuel upon delivery to the propeller.

[0037] Examples of physicochemical characteristics of the lubricant include the basicity (e.g., BN) of the lubricant, the composition of the lubricant (e.g., the type and / or proportion of additives, friction modifier additives, and / or base oil present in the lubricant), the shear stability of the lubricant, the kinematic viscosity of the lubricant, the viscosity index of the lubricant, the temperature of the lubricant when delivered to the propeller, and the pressure of the lubricant when delivered to the propeller. Optionally, the lubricant is a cylinder oil or a system oil.

[0038] Typically, the method includes modifying only one of these propeller characteristics during operation of each propeller. For example, the method includes obtaining information indicative of a fuel efficiency of a first internal combustion engine of the marine vessel based on operation of the first internal combustion engine with cylinder oil having a first kinematic viscosity during a first time period, and obtaining information indicative of a fuel efficiency of a second internal combustion engine of the marine vessel based on operation of the second internal combustion engine with cylinder oil having a second kinematic viscosity during the first time period concurrently with the first propeller, where the second kinematic viscosity is different from the first kinematic viscosity.

[0039] Optionally, the first time period is at least 24 hours (e.g., 1 day), at least 48 hours (e.g., 2 days), at least 7 days, or at least 14 days. Advantageously, a longer time period allows more information to be obtained, and thus improves the accuracy of identifying differences in propeller performance characteristics. For example, embodiments of the methods described herein provide an accuracy that allows a 0.1% change in a propeller operating parameter (such as fuel efficiency) to be identified as being due to differences in propeller characteristics used in the first and second propellers.

[0040] Optionally, one or more of the first time period and / or the second time period and / or the third time period continue over multiple voyages. For example, the vessel may be docked during the course of the time periods. Advantageously, embodiments of the method described herein may be performed during normal commercial operation of the vessel. For example, information indicative of propulsion performance characteristics may be obtained without altering the vessel's normal trading patterns, such that performing the method does not substantially adversely affect the vessel's normal operations.

[0041] Optionally, the first time period includes one or more portions of time during which the first propeller and the second propeller operate in a steady state. As used herein, "steady state" refers to operating conditions in which the propellers can operate in substantially the same manner (except for predetermined differences between propeller characteristic changes), and does not include periods during, for example, ship maneuvers or ship dockage.

[0042] In an embodiment, operating the propellers at steady state includes one or more of: operating the propellers such that the propeller speed and load are substantially constant (e.g., + / - 3%); operating the auxiliary inputs and outputs equally across both propellers; configuring the gas flow management systems (e.g., valves, turbines, etc.) to be in a predefined state at most all times (e.g., not switching between open and closed during steady state operation); and configuring the cooling system and cooling medium to be in a predefined state at most all times.

[0043] In an embodiment, the propellers are operated at a steady state, which provides a substantially stable force on each propeller component, which provides a substantially stable velocity (e.g., a stable linear or rotational velocity) within the propeller, which provides a substantially stable pressure on, for example, fluids and components within the propeller, and which provides a substantially stable temperature of, for example, fluids and components within the propeller.

[0044] Optionally, the first time period excludes one or more portions of time during which the first and second propellers are not operating at steady state. For example, when determining differences between performance characteristics of the first and second propellers, only information related to operation of the propellers under steady state conditions is considered. Advantageously, by determining propeller performance characteristics based only on operation of the propellers at steady state, artifacts are reduced (e.g., eliminated) when determining differences in performance characteristics resulting from differences in propeller operational changes.

[0045] Optionally, the second time period and / or the third time period includes one or more portions of time during which the first and second propellers operate in a steady state. Optionally, the second time period and / or the third time period excludes one or more portions of time during which the first and second propellers do not operate in a steady state.

[0046] Optionally, the performance characteristic is a first performance characteristic, and the method further includes obtaining information indicative of a second performance characteristic of the first propeller based on operation of the first propeller with the first change in the propeller characteristic during a first time period, obtaining information indicative of the second performance characteristic of the second propeller based on operation of the second propeller with the second change in the propeller characteristic during the first time period concurrently with the first propeller, and identifying a difference between the second performance characteristic of the first propeller and the second performance characteristic of the second propeller.

[0047] For example, the method may include analyzing a first performance characteristic (e.g., efficiency, such as fuel efficiency) and a second performance characteristic (e.g., atmospheric emission(s) from the propulsor). Advantageously, implementations of the method may provide information regarding a plurality of propulsor performance characteristics.

[0048] Optionally, the determining of the difference between the performance characteristics of the first propeller and the performance characteristics of the second propeller is performed on board the vessel. Alternatively, the determining is performed remotely from the vessel. For example, the determining is performed on land. Advantageously, performing the analysis remotely eliminates the need for a powerful computer on board the vessel. Optionally, the method includes communicating information indicative of the performance characteristics of the first vessel propeller and the second vessel propeller to a remote processor from on board the vessel. Thus, the processor obtains information indicative of the performance characteristics of the first propeller and the performance characteristics of the second propeller, and the processor performs the determining of the difference between the performance characteristics of the first propeller and the performance characteristics of the second propeller. Optionally, the information is communicated in real time or near real time. For example, the information is provided from the vessel to the remote processor every 10 minutes.

[0049] Optionally, the vessel is a marine vessel and the propulsion operations are performed at sea and the analysis is performed on land or remotely.

[0050] A second aspect of the present invention provides an apparatus for identifying an effect of a change in a propeller characteristic on the performance of a marine vessel propeller, the apparatus being configured to: obtain information indicative of performance characteristics of a first propeller of the marine vessel based on operation of the first propeller with a first change in the propeller characteristic, over a first time period; obtain information indicative of performance characteristics of a second propeller of the marine vessel based on operation of the second propeller with a second change in the propeller characteristic, over the first time period simultaneously with the first propeller, where the second change is different from the first change; and identify a difference between the performance characteristics of the first propeller and the performance characteristics of the second propeller.

[0051] For example, there is provided an apparatus configured to perform a method according to the first aspect.

[0052] Optionally, the apparatus comprises a controller, the controller comprising a processor for performing the determining.

[0053] Optionally, the apparatus comprises a receiver for receiving information indicative of a performance characteristic of the first propulsor and a performance characteristic of the second propulsor, respectively. In an embodiment, the receiver is a bus for receiving information from another component on the vessel. In an embodiment, the receiver is a satellite receiver for receiving information transmitted from a transmitter on the vessel.

[0054] A third aspect of the present invention provides a non-transitory computer-readable storage medium storing instructions which, when executed by a processor, cause the processor to perform a method according to the first aspect.

[0055] A fourth aspect of the present invention provides a method for determining performance characteristics of a propeller of a marine vessel, the method comprising: operating a first propeller of the marine vessel with a first change in a propeller characteristic during a first time period; operating a second propeller of the marine vessel with a second change in a propeller characteristic during the first time period simultaneously with the first propeller, the second change being different from the first change; determining performance characteristics of the first propeller based on the operation of the first propeller; and determining performance characteristics of the second propeller based on the operation of the second propeller.

[0056] Features described in relation to the first aspect of the present disclosure are expressly disclosed in combination with the fourth aspect to the extent compatible.

[0057] Optionally, determining the performance characteristic of the first propulsor and the performance characteristic of the second propulsor includes obtaining information from one or more sensors for sensing (e.g., determining) the performance characteristic or for sensing (e.g., determining) a characteristic corresponding to (e.g., proportional to) the performance characteristic. Optionally, obtaining the information is performed by one or more controllers. In an embodiment, the controller is onboard the vessel. Optionally, the controller is communicatively connected to each of the sensors such that the controller obtains the information from the one or more sensors. Optionally, the controller is configured to determine the performance characteristic based on the information received from the one or more sensors. For example, the controller is configured to determine the performance characteristic based on information indicative of a characteristic corresponding to (e.g., proportional to) the performance characteristic.

[0058] Optionally, the propeller performance characteristic is fuel efficiency. Optionally, determining the fuel efficiency of the first propeller based on the operation of the first propeller includes obtaining information from a first indicator to determine a power output of the first propeller, obtaining information from a first inlet flow meter to determine an amount of fuel supplied to the first propeller, and optionally obtaining information from a first return flow meter to determine an amount of fuel discharged from the first propeller. Determining the fuel efficiency of the second propeller based on the operation of the second propeller includes obtaining information from a second indicator to determine a power output of the second propeller, obtaining information from a second inlet flow meter to determine an amount of fuel supplied to the second propeller, and optionally obtaining information from a second return flow meter to determine an amount of fuel discharged from the second internal combustion engine.

[0059] Optionally, each flow meter is a mass flow meter. Advantageously, mass flow meters can provide more accurate information for determining the fuel efficiency of an engine due to changes in fuel density during operation, as compared to, for example, volumetric flow meters.

[0060] Advantageously, obtaining information from both the inlet and return flow meters may enable a more accurate determination of the mass of fuel consumed by the engine during operation. For example, the controller may be configured to determine the amount of fuel consumed by the engine during operation by determining the difference between the amount of fuel supplied to the engine via the inlet flow meter and the amount of fuel exiting the engine via the return flow meter.

[0061] Optionally, each of the first indicator and the second indicator identifies the power output of the first thruster and the power output of the second thruster, respectively, by a fuel pump index method, a load indicator method, a PV diagram, or a shaft dynamometer.

[0062] Optionally, the first indicator is a first shaft dynamometer for determining the power output of the first propeller and the second indicator is a second shaft dynamometer for determining the power output of the second propeller. Optionally, each shaft dynamometer comprises a dynamometer. Optionally, each shaft dynamometer comprises a torque meter. Optionally, each shaft dynamometer comprises a torque meter and / or a tachometer and / or a crankshaft angle sensor.

[0063] Optionally, the propeller performance is atmospheric emissions. Optionally, identifying the atmospheric emissions of the first propeller includes obtaining, from a first exhaust gas monitoring system, information for sensing a mass of the atmospheric emission(s) emitted from the first propeller via the first propeller exhaust. Optionally, identifying the atmospheric emissions of the second propeller includes obtaining, from a second exhaust gas monitoring system, information for sensing a mass of the atmospheric emission(s) emitted from the second propeller via the second propeller exhaust.

[0064] Optionally, the method further includes transmitting information indicative of the determined performance characteristics to a processor to determine differences between the performance characteristics. In embodiments, the information is transmitted to a processor on the vessel, e.g., via a communication conduit communicatively connecting the controller and the processor. In embodiments, the determined performance characteristics are transmitted to a processor remote from the vessel, e.g., a processor on land. In these embodiments, transmitting includes, for example, communicating the information from a controller on the vessel to a transmitter on the vessel, transmitting the information from the transmitter to a receiver on land or a receiver remote from the vessel (e.g., satellite transmission), and communicating the information from the receiver to a processor communicatively connected to the receiver.

[0065] Optionally, the transmitting of the information is performed at predetermined time intervals. For example, the method includes transmitting the information at 10 minute intervals. Alternatively, the transmitting of the information includes transmitting the information continuously.

[0066] A fifth aspect of the invention provides an apparatus configured to carry out a method according to the fourth aspect.

[0067] Optionally, the apparatus comprises a first propulsor, a second propulsor, one or more first performance characteristic sensors for obtaining information indicative of a performance characteristic of the first propulsor, one or more second performance characteristic sensors for obtaining information indicative of a performance characteristic of the second propulsor, and a processor for determining the performance characteristics of the first propulsor and the performance characteristics of the second propulsor, respectively.

[0068] Optionally, the apparatus further comprises a transmitter for transmitting information indicative of a performance characteristic of the first thruster and a performance characteristic of the second thruster, respectively.

[0069] Features described in relation to the fourth aspect are expressly disclosed in combination with the fifth aspect to the extent compatible.

[0070] A sixth aspect of the present invention provides a marine vessel comprising an apparatus according to the second aspect, an apparatus according to the fifth aspect, and / or a non-transitory computer readable storage medium according to the third aspect.

[0071] Features described in this specification in the context of one embodiment of the disclosure are expressly disclosed in combination with other embodiments, to the extent compatible.

[0072] Further features and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only with reference to the accompanying drawings, in which:

[0073] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0074] [Figure 1] 1 shows a schematic side view of an example marine vessel in accordance with an embodiment of the present invention; [Diagram 2]1 illustrates a schematic diagram of an exemplary apparatus for determining performance characteristics of a marine vessel propeller, in accordance with an embodiment of the present invention; [Diagram 3] 1 shows a flowchart illustrating an example of a method for identifying performance characteristics of a marine propulsion device, in accordance with an embodiment of the present invention. [Figure 4] 1 shows a schematic diagram of an exemplary apparatus for determining the effect of changes in propeller characteristics on the performance of a marine propeller, in accordance with an embodiment of the present invention; [Diagram 5] 1 shows a flowchart illustrating an example of a method for determining the effect of changes in propeller characteristics on the performance of a marine propulsion system, in accordance with an embodiment of the present invention. [Figure 6] 1 illustrates a schematic diagram of an exemplary computer-readable medium in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] 1 shows a schematic side view of an example of a maritime vessel according to an embodiment. In this embodiment, the vessel is a container ship 1. In other embodiments, the maritime vessel may be another type of cargo vessel, such as a tanker, dry bulk carrier, or reefer ship, or a passenger ship, or any other maritime vessel.

[0076] The marine vessel 1 has a hull 2 ​​and one or more engine rooms 3 inside the hull 2. The marine vessel 1 is powered by at least two internal combustion engines 4, 5, such as two-stroke auto-ignition combustion engines 4, 5 disposed in the engine room 3. The engines 4, 5 drive a propulsion mechanism 6 (such as one or more propellers). The vessel 1 may also include one or more auxiliary engines (known as generator sets) that provide power and / or heat to various power consumers on board the vessel 1.

[0077] The engines 4, 5 are marine two-stroke crosshead internal combustion engines. In the embodiment shown in FIG. 1, the engines 4, 5 are powered by marine heavy fuel oil. In alternative embodiments (not shown), the engines are powered by fuels other than heavy fuel oil, such as marine gas oil, marine diesel oil, marine gas oil, liquid natural gas, liquid petroleum gas, biofuel, methanol, ethanol, ammonia, hydrogen, methane, biomethane, or combinations thereof. In these embodiments, the fuel may be a natural or synthetic fuel. The engines 4, 5 are any suitable marine two-stroke crosshead internal combustion engines, such as diesel uniflow engines, or Otto cycle engines. Those skilled in the art will be familiar with the components and systems of the marine vessel 1, and further details thereof are omitted for the sake of brevity.

[0078] 2 illustrates a schematic diagram of an exemplary apparatus 200, in accordance with an embodiment of the present invention, for determining performance characteristics of a marine vessel propeller.

[0079] Communication connectors for communicating information between components of device 200 are shown with dashed lines.

[0080] The arrangement 200 comprises a first internal combustion engine 202 and a second internal combustion engine 204. In the arrangement 200 shown in Fig. 2, the first internal combustion engine 202 and the second internal combustion engine 204 correspond to the engines 4, 5 shown in Fig. 1. That is to say, the arrangement is arranged on a vessel 1.

[0081] The engines 202, 204 are configured to operate under identical operating conditions except for differences between engine characteristic variations, for example, the engines 202, 204 are configured to operate under identical operating conditions except for the kinematic viscosity of the cylinder oil supplied to each of the cylinders (not shown) of the engines 202, 204.

[0082] The first engine 202 is configured to receive fuel, such as heavy fuel oil, from a fuel tank (not shown) via a fuel inlet conduit 206. A first inlet mass flow meter 208 for sensing a mass of fuel delivered to the first engine 202 from the fuel tank is disposed along the fuel inlet conduit 206 between the fuel tank and the first engine 202. The first inlet mass flow meter 208 is communicatively coupled to a controller 210 such that the controller 210 can obtain information indicative of the mass of fuel delivered to the first engine 202 during operation of the first engine 202.

[0083] Not all of the fuel delivered to the first engine 202 is necessarily consumed during operation of the first engine 202. Therefore, the apparatus further comprises a fuel return conduit 212, along which the first engine 202 directs unconsumed fuel to an overflow tank (not shown).

[0084] A first return mass flow meter 214 for sensing a mass of fuel flowing from the first engine 202 to the overflow tank is disposed along the fuel return conduit 212 between the first engine 202 and the overflow tank. The first return mass flow meter 214 is communicatively connected to the controller 210 such that the controller can obtain information indicative of the mass of fuel flowing from the first engine 202 during operation of the first engine 202. The controller 210 is configured to determine an amount of fuel consumed by the first engine 202 during operation of the first engine 202 by determining a difference between information indicative of the mass of fuel delivered to the first engine 202 received from the first inlet mass flow meter 208 and information indicative of the mass of fuel flowing from the first engine 202 received from the first return mass flow meter 214.

[0085] The first engine 202 includes a crankshaft 216 for transmitting drive energy (in the form of rotational energy) from the first engine 202 to a propeller (not shown). A first shaft dynamometer 218 for sensing power return of the first engine 202 is disposed along the crankshaft 216. The first shaft dynamometer 218 includes a torque meter and a tachometer.

[0086] The first shaft dynamometer 218 is communicatively connected to the controller 210 such that the controller 210 can obtain information indicative of the power return of the first engine 202 during operation of the first engine 202.

[0087] The second engine 204 is configured to receive fuel, such as heavy fuel oil, from a fuel tank (not shown) via a fuel inlet conduit 226. A second inlet mass flow meter 220 for sensing a mass of fuel delivered to the second engine 204 from the fuel tank is disposed along the fuel inlet conduit 226 between the fuel tank and the second engine 204. The second inlet mass flow meter 220 is communicatively coupled to the controller 210 such that the controller 210 can obtain information indicative of the mass of fuel delivered to the second engine 204 during operation of the second engine 204.

[0088] The apparatus further includes a fuel return conduit 222, along which the second engine 204 flows unconsumed fuel to an overflow tank (not shown). A second return mass flow meter 224 is disposed along the fuel return conduit 222 between the second engine 204 and the overflow tank for sensing a mass of fuel flowing from the second engine 204 to the overflow tank. The second return mass flow meter 224 is communicatively coupled to the controller 210 such that the controller can obtain information indicative of the mass of fuel flowing from the second engine 204 during operation of the second engine 204.

[0089] The controller 210 is configured to determine the amount of fuel consumed by the second engine 204 during operation of the second engine 204 by determining a difference between information received from the second inlet mass flow meter 220 indicating the mass of fuel delivered to the second engine 204 and information received from the second return mass flow meter 224 indicating the mass of fuel flowed out of the second engine 204.

[0090] The second engine 204 includes a crankshaft 228 for transferring drive energy (in the form of rotational energy) from the second engine 204 to a propeller (not shown). A second shaft dynamometer 230 is disposed along the crankshaft 228 for sensing the power output of the second engine 204. The second shaft dynamometer 230 includes a torque meter and a tachometer.

[0091] The second shaft dynamometer 230 is communicatively connected to the controller 210 such that the controller 210 can obtain information indicative of the power output of the second engine 204 during engine operation of the second engine 204.

[0092] The controller 210 is configured to determine the fuel efficiency of the first engine 202 and the fuel efficiency of the second engine 204 based on information obtained from the flow meters 208 , 214 , 220 , 224 and the shaft dynamometers 218 , 230 .

[0093] The controller 210 is communicatively connected to a transmitter 232, preferably a satellite transmitter. The controller 210 and the transmitter 232 are configured to transmit the determined fuel efficiencies of the first engine 202 and the second engine 204 to a receiver located remotely from the vessel.

[0094] Figure 3 shows a flow chart illustrating an example of a method 300 according to an embodiment of the present invention. The example shown in Figure 3 is a method 300 for determining the fuel efficiency of an internal combustion engine that may be performed by the apparatus 200 shown in Figure 2. To facilitate understanding, reference numerals of the apparatus 200 are referred to in the description of Figure 3 where relevant.

[0095] The method 300 includes operating 302 the first internal combustion engine 202 with a first change in an engine characteristic during a first time period. In this example, the change is a first kinematic viscosity of cylinder oil delivered to the engine during operation of the engine 202 during the first time period.

[0096] The method 300 further includes determining 304 a fuel efficiency of the first engine 202 during the first time period. The determining 304 includes obtaining information indicative of a mass of fuel consumed by operation of the first engine 202 over the first time period (e.g., fuel delivered to the engine 202 minus fuel flowed out of the engine 202) and information indicative of a power output of the first engine 202 over the first time period.

[0097] In this example, the identification is based only on information about steady state operation of the first engine, e.g., the first time period excludes time periods during which the first engine 202 is not operating in a steady state condition.

[0098] The method 300 further includes operating 306 the second internal combustion engine 204 with a second change in an engine characteristic during a first time period concurrently with the first internal combustion engine 202. In this example, the change is a second kinematic viscosity of cylinder oil delivered to the engine during operation of the engine 204 during the second time period, the second kinematic viscosity being different from the first kinematic viscosity.

[0099] The method 300 further includes determining 308 a fuel efficiency of the second engine 204 during the first time period. The determining 308 includes obtaining information indicative of a mass of fuel consumed by operation of the second engine 204 over the first time period (e.g., fuel delivered to the engine 204 minus fuel flowed out of the engine 204) and information indicative of a power output of the second engine 204 over the first time period.

[0100] The method 300 further includes transmitting 310 information indicative of the fuel efficiency of the first engine 202 and the fuel efficiency of the second engine 204 to a receiver located remotely from the vessel. The transmitting 310 is performed at ten minute intervals.

[0101] FIG. 4 illustrates a schematic diagram of an exemplary apparatus 400, in accordance with an embodiment of the present invention.

[0102] The apparatus 400 comprises a receiver 402 for receiving information indicative of a fuel efficiency of the first engine 202 and a fuel efficiency of the second engine 204 during operation of the engines 202, 204 on the vessel 1. For example, the receiver 402 is configured to receive information from the transmitter 232 shown in FIG.

[0103] The apparatus 400 further comprises a controller 404. The controller 404 is communicatively coupled to the receiver 402 such that the controller 404 is able to receive information indicative of the fuel efficiency of the first engine 202 and the fuel efficiency of the second engine 204.

[0104] The controller 404 includes a processor 406. The processor 406 is configured to execute a method 500 shown in FIG.

[0105] 5 shows a flow chart illustrating an example of a method 500 according to another embodiment of the present invention. The method 500 shown in FIG. 5 can be suitably performed by the apparatus 400 shown in FIG.

[0106] 5 is directed to identifying differences in engine fuel efficiency. Other embodiments (not shown) may instead be directed to identifying differences between other propulsion performance characteristics, such as atmospheric emission(s).

[0107] The method 500 includes obtaining 502 information indicative of a fuel efficiency of a first engine 202 based on operation of the engine 202 during a first time period with a first change in an engine characteristic. As described above, in this example, the first change in the engine characteristic is a first kinematic viscosity of cylinder oil delivered to the engine 202.

[0108] The method 500 further includes obtaining 504 information indicative of a fuel efficiency of the second engine 204 based on operating the engine 204 during the first time period concurrently with the first engine 202 with a second change in the engine characteristic. In this example, the second change in the engine characteristic is a second kinematic viscosity of cylinder oil delivered to the engine 204, the second kinematic viscosity being different than the first.

[0109] The method 500 further includes determining 506 a difference between a fuel efficiency of the first engine 202 operated with cylinder oil having a first kinematic viscosity for a first period of time and a fuel efficiency of the second engine 204 operated with cylinder oil having a second kinematic viscosity for the first period of time.

[0110] Determining 506 includes determining normality and homoscedasticity of the obtained information, determining differences between the obtained information, and determining the statistical significance of the differences.

[0111] In some embodiments, the method 500 ends after identifying the difference between the fuel efficiencies during the first time period 506. However, the method 500 illustrated in Figure 5 represents an "ABA" testing method.

[0112] The method 500 further includes obtaining 508 information indicative of a fuel efficiency of the first engine 202 based on operation of the engine 202 with a second change in the engine characteristic during a second time period, i.e., during the second time period, the first engine 202 operates using cylinder oil having a second kinematic viscosity.

[0113] The method 500 further includes obtaining 510 information indicative of a fuel efficiency of the second engine 204 based on operation of the engine 204 with a first change in engine characteristic during a second time period concurrently with the first engine 202. That is, during the second time period, the second engine 204 operates using cylinder oil having a first kinematic viscosity.

[0114] The method 500 further includes determining 512 a difference between a fuel efficiency of the first engine 202 operated with cylinder oil having the second kinematic viscosity for the second period of time and a fuel efficiency of the second engine 204 operated with cylinder oil having the first kinematic viscosity for the second period of time.

[0115] Determining 512 includes determining normality and homoscedasticity of the obtained information, determining differences between the obtained information, and determining the statistical significance of the differences.

[0116] The method 500 includes obtaining 514 information indicative of a fuel efficiency of the first engine 202 based on operation of the engine 202 with a first change in engine characteristic during a third time period, i.e., during the third time period, the first engine 202 operates using cylinder oil having a first kinematic viscosity (i.e., with the same engine characteristic change used during the first time period).

[0117] The method 500 further includes obtaining 516 information indicative of a fuel efficiency of the second engine 204 based on operation of the engine 204 with a second change in engine characteristics during a third time period concurrently with the first engine 202. That is, during the third time period, the second engine 204 operates using cylinder oil having a second kinematic viscosity (i.e., with the same engine characteristic change as used during the first time period).

[0118] The method 500 further includes determining 518 a difference between a fuel efficiency of the first engine 202 operated with cylinder oil having the first kinematic viscosity during the third time period and a fuel efficiency of the second engine 204 operated with cylinder oil having the second kinematic viscosity during the third time period.

[0119] Determining 518 includes determining normality and homoscedasticity of the obtained information, determining differences between the obtained information, and determining the statistical significance of the differences.

[0120] The method 500 further includes determining 520 a representative (average) difference between the fuel efficiency of the first time period, the fuel efficiency of the second time period, and the fuel efficiency of the third time period. In calculating the average difference, for example, the absolute value of the difference is used so that the difference determined during the second time period does not cancel out the difference determined during the first time period. Typically, the "ABA" test method 500 is capable of determining a statistically significant fuel efficiency difference with an accuracy of 0.5% or 0.1%. In a specific example, each of the first time period, the second time period, and the third time period is at least 14 days in duration, and the "ABA" test method 500 is capable of determining a statistically significant fuel efficiency difference with an accuracy of 0.1%.

[0121] The method 500 further includes identifying 522 the identified differences as being due to differences between engine characteristic changes. For example, the method 500 includes identifying that the differences in fuel efficiency are due to differences in kinematic viscosity between the cylinder oils used.

[0122] 6 illustrates a schematic diagram of a non-transitory computer-readable storage medium 600 according to an embodiment. The non-transitory computer-readable storage medium 600 stores instructions 630 that, when executed by a processor 620 of a controller 610, cause the processor 620 to perform a method according to an embodiment. In an embodiment, the instructions 630 include instructions for performing any of the example methods described herein, such as the method 500 described above with reference to FIG.

[0123] In other embodiments, two or more of the above-described embodiments may be combined. In other embodiments, features of one embodiment may be combined with features of one or more other embodiments.

[0124] Exemplary embodiments of the invention have been discussed with particular reference to the illustrated examples. It will be appreciated, however, that variations and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. 1. A method for determining the effect of changes in propeller characteristics on the performance of a marine propeller, comprising: obtaining information indicative of a performance characteristic of a first propeller of the marine vessel based on operation of the first propeller during a first time period with a first change in the propeller characteristic; obtaining information indicative of the performance characteristics of a second propeller of the marine vessel based on operation of the second propeller during the first time period concurrently with the first propeller due to a second change in the propeller characteristic, the second change being different from the first change; determining a difference between the performance characteristics of the first thruster and the performance characteristics of the second thruster; The method comprising:

2. obtaining information indicative of the performance characteristic of the first propeller of the marine vessel based on operation of the first propeller with the second change in the propeller characteristic during a second time period; obtaining information indicative of the performance characteristics of the second propeller of the marine vessel based on operation of the second propeller due to the first change in the propeller characteristic concurrently with the first propeller during the second time period; determining a difference between the performance characteristic of the first thruster during the second time period and the performance characteristic of the second thruster during the second time period; The method of claim 1 further comprising:

3. obtaining information indicative of the performance characteristics of the first propeller of the marine vessel based on operation of the first propeller due to the first change in the propeller characteristic during a third time period; obtaining information indicative of the performance characteristics of the second propeller of the marine vessel based on operation of the second propeller due to the second change in the propeller characteristic during the third time period simultaneously with the first propeller; determining a difference between the performance characteristic of the first thruster during the third time period and the performance characteristic of the second thruster during the third time period; The method of claim 2 further comprising:

4. The method of claim 1 , wherein the performance characteristic is the efficiency of the propulsor.

5. The method of claim 1 , wherein the propeller characteristic is a fluid within the propeller, a component of the propeller, an operating parameter of the propeller, a component of a propeller auxiliary, or an operating parameter of a propeller auxiliary.

6. 10. The method of claim 1, wherein the first period includes one or more portions of time during which the first thruster and the second thruster operate in a steady state.

7. The performance characteristic is a first performance characteristic, and the method comprises: obtaining information indicative of a second performance characteristic of the first propeller based on operation of the first propeller during the first time period due to the first change in the propeller characteristic; obtaining information indicative of the second performance characteristic of the second propeller based on operation of the second propeller due to the second change in the propeller characteristic concurrently with the first propeller during the first time period; determining a difference between the second performance characteristic of the first thruster and the second performance characteristic of the second thruster; The method of claim 1 further comprising:

8. 10. The method of claim 1, wherein each of the first propulsor and the second propulsor is an internal combustion engine.

9. 1. An apparatus for determining the effect of changes in propeller characteristics on the performance of a marine propeller, comprising: obtaining information indicative of a performance characteristic of a first propeller of the marine vessel based on operation of the first propeller during a first time period with a first change in the propeller characteristic; obtaining information indicative of the performance characteristics of a second propeller of the marine vessel based on operation of the second propeller during the first time period concurrently with the first propeller due to a second change in the propeller characteristic, the second change being different from the first change; determining a difference between the performance characteristics of the first thruster and the performance characteristics of the second thruster; The apparatus is configured to perform the following:

10. 10. A non-transitory computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform the method of claim 1.

11. 1. A method for identifying performance characteristics of a marine vessel propulsion system, comprising: operating a first propeller of the marine vessel with a first change in propeller characteristics during a first time period; operating a second propeller of the marine vessel with a second change in the propeller characteristic simultaneously with the first propeller and during the first time period, the second change being different from the first change; determining a performance characteristic of the first thruster based on the operation of the first thruster; and determining the performance characteristics of the second thruster based on the operation of the second thruster; and The method comprising:

12. 12. The method of claim 11 , wherein the determining the performance characteristic of the first thruster and the determining the performance characteristic of the second thruster include obtaining information from one or more sensors for sensing the performance characteristic or for sensing a characteristic corresponding to the performance characteristic.

13. the performance characteristic is fuel efficiency; Determining the fuel efficiency of the first propulsor based on the operation of the first propulsor includes: obtaining information from a first indicator to identify a power output of the first propulsion device; obtaining information from a first inlet flow meter to identify an amount of fuel supplied to the first propeller; and optionally obtaining information from a first return flow meter to identify an amount of fuel flowing out of the first propeller; Determining the fuel efficiency of the second propulsor based on the operation of the second propulsor includes: obtaining information from a second indicator to identify a power output of the second propulsion device; obtaining information from a second inlet flow meter to identify an amount of fuel supplied to the second propeller; Optionally, obtaining information from a second return flow meter to identify the amount of fuel flowing out of the second propeller; The method of claim 11 , comprising:

14. 12. An apparatus configured to perform the method of claim 11, comprising: a first thruster; and a second thruster; and one or more first performance characteristic sensors for obtaining information indicative of the performance characteristic of the first propulsor; one or more second performance characteristic sensors for obtaining information indicative of the performance characteristic of the second propulsor; a processor for determining the performance characteristics of the first thruster and the performance characteristics of the second thruster, respectively; The device comprising:

15. A vessel comprising an apparatus according to claim 9, a non-transitory computer-readable storage medium according to claim 10, and / or an apparatus according to claim 14.

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