Production of cylinder oil

Abstract

A method is disclosed for producing cylinder oil with one or more varying kinematic viscosities for use in a marine reciprocating internal combustion engine. The method includes: providing a first fluid having a first kinematic viscosity and a first BN; providing a second fluid having a second kinematic viscosity and a second BN, the second kinematic viscosity being different from the first kinematic viscosity; and blending the first fluid and the second fluid in a first ratio to produce a first cylinder oil having a kinematic viscosity equal to or less than 14 mm² / s at 100°C.

Description

[Technical Field]

[0001] This invention relates to a method for producing one or more cylinder oils with varying kinematic viscosities for a marine reciprocating internal combustion engine, a method for operating a marine reciprocating internal combustion engine, an apparatus for preparing a cylinder oil, and a marine vessel comprising the apparatus for preparing a cylinder oil. [Previous Technology]

[0002] Marine vessels, such as container ships, have engines powered by heavy fuel oil or similar fuels. Fuel consumption constitutes the largest portion of the daily operating costs of marine vessels. Furthermore, the amount of fuel directly consumed corresponds to the amount of pollutants generated (e.g., carbon dioxide (CO2), nitrogen oxides (NOx), and / or sulfur oxides (SOx)). Fuel consumption is affected by the efficiency of engine operation and / or the speed at which the engine is operated.

[0003] The components of an engine on a marine vessel require lubrication during operation. The effectiveness of lubrication affects the efficiency of engine operation, and thus, in turn, affects the amount of fuel consumed during engine operation. Frictional losses in the engine can be reduced by proper lubrication.

[0004] Cylinder oil is used to lubricate the cylinders in marine reciprocating internal combustion engines. Cylinder oil has various functions, including reducing mechanical wear of pistons, piston rings and cylinder liners by forming an oil film between the piston and / or piston rings and cylinder liner to reduce friction between surfaces.

[0005] The ability to form an oil film with suitable lubricating properties between the piston and / or piston rings and the cylinder head gasket depends at least in part on the viscosity of the cylinder oil. Higher viscosity is believed to provide a thicker oil film between the surfaces, thereby providing better wear control. Cylinder oil typically has a viscosity of at least 18.5 mm² / s at 100°C. Leading non-profit associations such as CIMAC and manufacturers of marine reciprocating internal combustion engines state that cylinder oils must have an SAE (Society of Automotive Engineers) viscosity rating of SAE 50 (at least 16.3 mm² / s at 100°C) for the safe operation of marine reciprocating internal combustion engines such as two-stroke crosshead engines. Cylinder oils with lower kinematic viscosity are believed to have inferior lubricating properties because the thinner oil film formed between the surfaces leads to increased wear on engine components, increased drag friction, and increased corrosion.

[0006] Another function of cylinder oil is to reduce corrosion of piston and gasket materials by neutralizing the sulfuric acid formed from the combustion of sulfur-containing fuels. The ability to reduce piston and cylinder gasket corrosion depends at least in part on the basicity of the cylinder oil, known as its base number (BN). BN is typically expressed as milligrams of potassium hydroxide per gram of oil (mg KOH / g). For marine applications, cylinder oils typically have a BN of 25 to 140, depending on the sulfur content of the fuel used to power the engine. However, the required BN for cylinder oil can vary during engine operation due to variations in fuel sulfur content or engine load.

[0007] Offshore vessels may be equipped with blending systems to produce onboard cylinder oils with alkalinity that varies in response to changing demands during engine operation. The procedure is specified by the target BN of the required cylinder oil and does not take into account the target kinematic viscosity.

[0008] The embodiments of the present invention aim to reduce the amount of fuel consumption and pollutants generated during the operation of marine reciprocating internal combustion engines, while solving the aforementioned problems. [Summary of the Invention]

[0009] A first aspect of the present invention provides a method for producing cylinder oil with one or more varying kinematic viscosities for a marine reciprocating internal combustion engine, the method comprising: providing a first fluid having a first kinematic viscosity and a first BN; providing a second fluid having a second kinematic viscosity and a second BN, the second kinematic viscosity being different from the first kinematic viscosity; and blending the first fluid and the second fluid at a first ratio to produce a first cylinder oil having a kinematic viscosity equal to or less than 14 mm² / s at 100°C.

[0010] The inventors have confirmed that providing cylinder oil with reduced kinematic viscosity (e.g., below the minimum kinematic viscosity recommended by the engine manufacturer) allows the cylinder oil to lubricate during engine operation and reduces frictional losses. The lower viscosity of the cylinder oil means a thinner oil film forms between the piston and cylinder head gasket, resulting in reduced hydrodynamic friction. This reduction in frictional losses leads to reduced fuel consumption during engine operation and, consequently, a reduction in the amount of contaminants generated.

[0011] Surprisingly, the inventors have further confirmed that the reduced kinematic viscosity has no significant negative effect on the oil's ability to control activity and / or cylinder head gasket wear, and provides stronger control over engine component wear in examples. Thus, for the first time, the inventors have provided a cylinder oil with low kinematic viscosity that can be reliably used in marine reciprocating internal combustion engines.

[0012] Depending on the circumstances, the method may be implemented offshore, such as on a vessel at sea. Advantageously, implementing the method on a vessel at sea, compared to onshore, enables the cylinder oil to meet the requirements of the engine during operation.

[0013] All kinematic viscosities described herein are measured at a temperature of 100°C unless otherwise stated. The kinematic viscosity of oil at 100°C can be expressed in centistokes (cSt). Therefore, the first cylinder oil having a kinematic viscosity equal to or less than 14 mm² / s at 100°C is equivalent to 14 cSt. In an example, the first cylinder oil has a kinematic viscosity equal to or less than 13.5 mm² / s, or equal to or less than 13 mm² / s, or equal to or less than 12.5 mm² / s, or equal to or less than 10 mm² / s. In an example, the first cylinder oil has a kinematic viscosity equal to or greater than 8 mm² / s (such as 8 mm² / s to 14 mm² / s, or 8 mm² / s to 12.5 mm² / s, or 8 mm² / s to 10 mm² / s).

[0014] Depending on the circumstances, the first cylinder oil has a kinematic viscosity corresponding to one of the SAE viscosity grades SAE 40, SAE 30, or SAE 20. The first cylinder oil has any suitable viscosity index for lubricating piston liners and piston rings in the cylinders of an engine. In an example, the first cylinder oil has a viscosity index of 59 to 120.

[0015] Depending on the circumstances, the first cylinder oil has one of the following BN: 15 to 160 mg KOH / g, 25 to 150 mg KOH / g, 40 to 140 mg KOH / g, or 50 to 120 mg KOH / g.

[0016] Depending on the circumstances, the method includes determining a target kinematic viscosity of the first cylinder oil based on an engine operating parameter and / or an engine condition parameter.

[0017] Depending on the circumstances, the method includes: determining a target ratio range between the first fluid and the second fluid based on a set of parameters including the first kinematic viscosity and the second kinematic viscosity, the target ratio range corresponding to the target kinematic viscosity of the first cylinder oil; and performing the blending of the first fluid and the second fluid such that the first ratio is set within the target ratio range corresponding to the target kinematic viscosity of the first cylinder oil. Therefore, the cylinder oil is adapted to have a kinematic viscosity suitable for engine operation and / or conditions during engine operation.

[0018] Where appropriate, for any target ratio range described herein, the upper bound of the target ratio range is equal to the lower bound of the target ratio range. For example, the target ratio range is a single target ratio, and the blending is performed such that the first ratio is a first target ratio.

[0019] Depending on the circumstances, the blending includes blending a third fluid having a third kinematic viscosity and a third BN with the first fluid and the second fluid to produce the first cylinder oil. The third fluid is blended with the first fluid and the second fluid in a ratio to produce the first cylinder oil. Providing a third fluid allows for control of the kinematic viscosity and alkalinity of the first cylinder oil.

[0020] Depending on the circumstances, the method includes determining one of the target BNs of the first cylinder oil based on an engine operating parameter or an engine condition parameter.

[0021] Depending on the circumstances, the method includes: determining a target ratio range between the first fluid and the second fluid based on a parameter set that includes at least one of the first BN, the second BN, and the third BN, the target ratio range corresponding to the target BN of the first cylinder oil; and performing the blending such that the first ratio is set within the target ratio corresponding to the target BN of the first cylinder oil. In an example, the parameter set also includes at least one of the following: the kinematic viscosity of the first fluid; the kinematic viscosity of the second fluid; the kinematic viscosity of the third fluid; and the BN of the third fluid. In an example, the determination further includes determining the ratio of the third fluid to the first fluid and / or the ratio of the third fluid to the second fluid. For example, the determination includes determining the amount of the first fluid, the second fluid, and the third fluid to be blended together to produce the first cylinder oil.

[0022] Depending on the circumstances, the method further includes producing a second cylinder oil by blending the first fluid and the second fluid at a second ratio different from the first ratio, the second cylinder oil having a kinematic viscosity greater than that of the first cylinder oil. During marine engine operation, cylinder lubrication requirements typically change over time. For example, the engine operates at different speeds. In an example, the second cylinder oil has a kinematic viscosity adapted to the new lubrication requirements of the cylinder. The second cylinder oil has any suitable kinematic viscosity. In an example, the second cylinder oil has a kinematic viscosity lower than the minimum kinematic viscosity recommended by the engine manufacturer, such as a kinematic viscosity equal to or less than 14 mm² / s, or equal to or less than 13.5 mm² / s, or equal to or less than 13 mm² / s, or equal to or less than 12.5 mm² / s, or equal to or less than 10 mm² / s. In one example, the second cylinder oil has a kinematic viscosity equal to or greater than 8 mm² / s (such as 8 mm² / s to 14 mm² / s, or 8 mm² / s to 12.5 mm² / s, or 8 mm² / s to 10 mm² / s). In other examples, the second cylinder oil has a kinematic viscosity greater than 14 mm² / s (such as greater than or equal to 16.5 mm² / s) (e.g., a kinematic viscosity within the range recommended by the engine manufacturer).

[0023] Depending on the circumstances, the first cylinder oil may have a different BN than the second cylinder oil. During engine operation, the sulfur content of the fuel oil may change, for example, resulting in the generation of different amounts of sulfuric acid. Providing a second cylinder oil with a different BN than the first cylinder oil means providing the cylinder with a cylinder oil of suitable alkalinity.

[0024] Depending on the circumstances, the second cylinder oil has one of the following BN: 15 to 160 mg KOH / g, 25 to 150 mg KOH / g, 40 to 140 mg KOH / g, or 50 to 120 mg KOH / g.

[0025] Depending on the circumstances, the method includes determining a target kinematic viscosity of the second cylinder oil based on an engine operating parameter or an engine condition parameter.

[0026] Depending on the circumstances, the method includes: determining a target ratio range between the first fluid and the second fluid based on a set of parameters including the first kinematic viscosity and the second kinematic viscosity, the target ratio range corresponding to the target kinematic viscosity of the second cylinder oil; and performing the mixing of the first fluid and the second fluid such that the second ratio is set within the target ratio range corresponding to the target kinematic viscosity of the second cylinder oil.

[0027] Depending on the circumstances, the method includes determining one of the target BNs of the second cylinder oil based on an engine operating parameter or an engine condition parameter.

[0028] Depending on the circumstances, the production of the second cylinder oil includes blending the first fluid and the second fluid with a third fluid having a third kinematic viscosity and a third BN to produce the second cylinder oil. The method includes: determining a target ratio range between the first fluid and the second fluid based on a parameter set including at least the first BN, the second BN, and the third BN, the target ratio range corresponding to the target BN of the second cylinder oil; and performing the blending such that the second ratio is set within the target ratio corresponding to the target BN of the second cylinder oil. In an example, the determination further includes determining the ratio of the third fluid to the first fluid and / or the ratio of the third fluid to the second fluid. For example, the determination includes determining the amount of the first fluid, the second fluid, and the third fluid to be blended together to produce the second cylinder oil.

[0029] Depending on the circumstances, the engine operating parameters or engine condition parameters may be at least one of the following: fuel sulfur content; engine load; engine speed; relative air humidity; cylinder iron wear emissions, total iron wear emissions, iron oxide emissions; cylinder lubricant residue BN; and cylinder oil gasket temperature.

[0030] Depending on the circumstances, the first fluid is a system oil. In examples, the system oil has a kinematic viscosity of 10 to 15 mm² / s. Typically, the system oil has a kinematic viscosity corresponding to SAE viscosity grade SAE 30; for example, the system oil has a kinematic viscosity of 11 to 12 mm² / s. In examples, the system oil is at least partially used system oil, such as a used system oil. The use of used system oil reduces engine operating costs. The system oil typically has a BN of 5 to 30 (such as 5 to 10). In examples, such as in the case where the system oil is a new cylinder oil, the system oil has a BN of 5 to 8.

[0031] Depending on the circumstances, the second fluid may be an additive package, new cylinder oil, or at least partially used cylinder oil.

[0032] Depending on the circumstances, the third fluid is a base oil. In an example, the base oil has a kinematic viscosity of 3 to 8 mm² / s. Typically, the base oil has a kinematic viscosity corresponding to SAE viscosity grade SAE 20; for example, the base oil has a kinematic viscosity of 4 to 7 mm² / s. Advantageously, the base oil is generally low in cost, and therefore including the base oil in the blend reduces the cost of producing cylinder oil. The base oil typically has a BN of less than 1 (such as less than 0.5, or less than 0.1).

[0033] Depending on the circumstances, at least one of the first fluid, the second fluid, and the third fluid may be at least partially used oil, such as used oil. The use of used system oil reduces engine operating costs.

[0034] Depending on the circumstances, at least one of the first fluid, the second fluid, and (if present) the third fluid may be a single-stage oil; for example, each of the first fluid, the second fluid, and (if present) the third fluid may be a single-stage oil. Depending on the circumstances, at least one of the first fluid, the second fluid, and (if present) the third fluid may be a multi-stage oil; for example, each of the first fluid, the second fluid, and (if present) the third fluid may be a multi-stage oil.

[0035] Depending on the circumstances, the first cylinder oil and / or the second cylinder oil may be all-loss cylinder oil.

[0036] A second aspect of the present invention provides a method for operating a marine reciprocating internal combustion engine, the method comprising: producing a cylinder oil by the above method, the cylinder oil having a kinematic viscosity equal to or less than 14 mm² / s at 100°C; and supplying the cylinder oil to a cylinder of the marine reciprocating internal combustion engine.

[0037] Surprisingly, the inventors have determined that cylinder oil with a viscosity of less than 14 mm² / s can maintain the safe operation of marine internal reciprocating engines (such as two-stroke crosshead engines).

[0038] Depending on the circumstances, the kinematic viscosity of the cylinder oil is lower than the minimum kinematic viscosity of the cylinder oil recommended by the manufacturer for the marine reciprocating internal combustion engine.

[0039] Depending on the circumstances, the vessel operates its reciprocating internal combustion engines at 60% or less of one engine load. For example, the engines may operate at speeds significantly below their maximum speed (sometimes referred to as "deceleration"). In other instances, the vessel operates its reciprocating internal combustion engines at more than 60% of one engine load (such as up to 70% or 80%).

[0040] Depending on the circumstances, the ship uses a reciprocating internal combustion engine, which is a one- or two-stroke crosshead engine. In this example, the two-stroke crosshead engine is a low-speed engine.

[0041] A third embodiment of the present invention provides an apparatus for preparing a cylinder oil, the apparatus comprising: a blender; a first container for containing a first fluid having a first kinematic viscosity and a first BN, the first container being selectively fluid-connected to the blender; a second container for containing a second fluid having a second kinematic viscosity and a second BN, the second container being selectively fluid-connected to the blender; and a controller configured to: determine the amount of the first fluid and the amount of the second fluid supplied to the blender for providing a cylinder oil having a desired target viscosity and a target BN, the target kinematic viscosity being equal to or less than 14 mm² / s at 100°C.

[0042] Depending on the circumstances, the controller is configured to cause the blender to blend the first fluid and the second fluid in a determined ratio (e.g., blending the determined amount of the first fluid and the determined amount of the second fluid) to produce the cylinder oil.

[0043] Depending on the circumstances, the device is on a ship at sea.

[0044] Depending on the circumstances, the first container may contain the first fluid. The first fluid may be, for example, system oil.

[0045] Depending on the circumstances, the second container may contain the second fluid. The second fluid may be, for example, an additive package, new cylinder oil, or used cylinder oil.

[0046] Depending on the circumstances, the apparatus may further include a third container for containing a third fluid having a third kinematic viscosity and a third BN, the third container being optionally in fluid communication with the blender. The third container may contain, for example, the third fluid, such as a base oil.

[0047] Depending on the circumstances, the apparatus includes a storage tank for storing cylinder oil produced by the apparatus. The storage tank is connected to the blender via a conduit, which may include: a valve allowing selective fluid communication between the storage tank and the blender; and / or a pump for pumping the produced cylinder oil from the blender to the storage tank. Depending on the circumstances, the storage tank may be selectively fluidly connected to a cylinder gasket of a cylinder via, for example, a valve for controlling the flow of cylinder oil from the storage tank to the cylinder gasket; and / or a pump for pumping cylinder oil from the storage tank to the cylinder gasket.

[0048] Depending on the circumstances, the blender of the equipment may be selectively fluidly connected to a cylinder gasket of a cylinder for supplying the produced cylinder oil to the cylinder gasket.

[0049] Where appropriate, the controller includes a memory and one or more processors, and is communicatively connected to and used to control each of the following: a first valve for controlling the flow of a first fluid from the first container to the blender and / or a first pump for pumping the first fluid from the first container to the blender; a second valve for controlling the flow of the first fluid from the second container to the blender and / or a second pump for pumping the second fluid from the second container to the blender; a third valve for controlling the flow of a third fluid from the third container and / or a third pump for pumping the third fluid from the third container to the blender; and the blender.

[0050] Depending on the circumstances, the controller is configured to receive data indicating an engine condition parameter and / or an engine operating parameter and / or a fluid condition parameter.

[0051] A fourth aspect of the present invention provides a marine vessel that includes the equipment described above with respect to the third aspect.

[0052] Depending on the circumstances, the vessel at sea may be a cargo ship, such as a container ship, tanker, bulk carrier, or refrigerated ship. Depending on the circumstances, the vessel at sea may be a passenger ship.

[0053] Depending on the circumstances, the vessel at sea is a container ship.

[0054] The description of one aspect of the present invention is explicitly disclosed in conjunction with any and all other aspects to achieve compatibility of such aspects.

[0055] Further features and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention, which are given by way of example only and are made with reference to the accompanying drawings. [Simplified Explanation of the Diagram]

[0101] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which: FIG1 shows a schematic side view of an example of a marine vessel according to an embodiment of the invention.

[0102] Figure 2 shows a schematic diagram of an example apparatus for preparing cylinder oil according to one embodiment of the present invention.

[0103] Figure 3 shows a schematic diagram of an example apparatus for preparing cylinder oil according to another embodiment of the present invention.

[0104] Figure 4 shows a flowchart illustrating an example of a method for producing one or more cylinder oils according to an embodiment of the present invention.

[0105] Figure 5 shows a flowchart illustrating an example of a method for producing one or more cylinder oils according to another embodiment of the present invention.

[0106] FIG6 shows a flowchart illustrating an example of a method for operating a marine reciprocating internal combustion engine according to an embodiment of the present invention.

Implementation Method

[0107] Figure 1 shows a schematic side view of one example of a maritime vessel according to an example. In this embodiment, the vessel is a container ship 1. In other embodiments, the maritime vessel may be another type of cargo ship, such as an oil tanker using cylinder oil, a bulk dry cargo ship, a refrigerated ship, a passenger ship, or any other maritime vessel.

[0108] The marine vessel 1 has a hull 2 ​​and one or more engine rooms 3 within the hull 2. The marine vessel 1 is powered by one or more large internal combustion engines 4 (such as four-stroke or two-stroke self-igniting combustors 4) located within the engine room 3. The engines 4 drive propulsion mechanisms (such as one or more propellers). The vessel 1 may also include one or more auxiliary engines (referred to as engine packs) that provide electricity and / or heat to various electrical consumers on the vessel 1. The vessel 1 also includes equipment 10, 20 for preparing cylinder oil for supplying cylinder oil to the engines 4. The equipment 10, 20 may be any equipment for preparing cylinder oil described herein as an embodiment of the invention, such as the equipment shown in FIG. 2 or FIG. 3.

[0109] Engine 4 is a marine two-stroke internal combustion engine. In the example shown in Figure 1, engine 4 is powered by marine heavy fuel oil. In other examples (not shown), the marine two-stroke internal combustion engine is powered by fuels other than heavy fuel oil, such as marine light oil, marine diesel, marine gasification oil, liquefied natural gas, liquefied petroleum gas, biofuels, methanol, ethanol, ammonia, hydrogen, methane, biomethane, or combinations thereof. In these examples, the fuel may be natural or synthetic. The two-stroke internal combustion engine is any suitable engine, such as a diesel unidirectional flow engine or an Otto cycle engine. Those skilled in the art are familiar with the components and systems of marine vessel 1, and therefore, for the sake of brevity, a more detailed description of these components and systems is omitted.

[0110] Figure 2 shows a schematic diagram of an apparatus 10 for preparing cylinder oil according to an example. The apparatus 10 is used to supply cylinder oil to the cylinder liner of an engine such as the engine 4 of a marine vessel shown in Figure 1 or any variant thereof described herein.

[0111] Generally, the device 10 includes: a blender 110 for blending fluids to provide cylinder oil; a first container 120 for containing a first fluid having a first kinematic viscosity and a first BN, the first container 120 being selectively in fluid communication with the blender 110; a second container 130 for containing a second fluid having a second kinematic viscosity and a second BN, the second container 130 being selectively in fluid communication with the blender 110; and a controller 140 configured to determine the amount of the first fluid and the amount of the second fluid (e.g., a ratio of the first fluid to the second fluid) to be supplied to the blender 110 to provide cylinder oil having a desired target viscosity and a target BN, the target kinematic viscosity being equal to or less than 14 mm² / s. In an example, the controller 140 is further configured to cause the blender 110 to blend the first fluid and the second fluid at a determined ratio.

[0112] More precisely, in FIG. 2, a first container 120 is connected to a blender 110 via a valve 122 through which a first fluid flows from the first container 120 to the blender 110. The valve is used to control the flow of the first fluid from the first container 120 to the blender 110. For example, the valve can be closed to prevent or impede the flow of the first fluid from the first container 120 to the blender 110, and can be opened to allow the first fluid to flow from the first container 120 to the blender 110. Thus, the first container 120 and the blender 110 are selectively in fluid communication. Depending on the situation, the valve 122 can be operated to allow restricted flow of the first fluid from the first container 120 to the blender 110 (e.g., the valve 122 can be "partially" closed or "partially" open). The valve can be operated manually or via a controller further described herein. In other instances (not shown), the first container 120 may be in fluid communication with the blender 110 via a pump for pumping a first fluid from the first container 120 to the blender 110.

[0113] In one example, the first container 120 contains a first fluid, such as system oil. The system oil is an oil suitable for use in the crankcase lubrication system of a low-speed two-stroke marine diesel engine. The system oil may be initial oil (e.g., not yet used in the crankcase lubrication system), in which case the first container 120 is typically a reservoir for storing initial system oil. Alternatively, the system oil is at least partially used system oil, such as system oil that has circulated around the crankcase lubrication system. In this case, in one example, the first container 120 is a reservoir for storing used system oil. In one example, such a used system oil reservoir is fluidly connected to the crankcase to receive used system oil from the crankcase. In one example, the used system oil reservoir is connected to the crankcase via a pump to pump the used system oil from the crankcase to the used system oil reservoir. In other examples where the system oil is at least partially used system oil, the first container 120 is inside the crankcase of the engine, or is the crankcase of the engine. For example, the first container 120 is the oil tank in the crankcase of the engine.

[0114] In Figure 2, the second container 130 is connected to the blender 110 via a valve 132 through which a second fluid flows from the second container 130 to the blender 110. More precisely, the valve is used to control the flow of the second fluid from the second container 130 to the blender 110. For example, the valve can be closed to prevent or impede the flow of the second fluid from the second container 130 to the blender 110, and can be opened to allow the second fluid to flow from the second container 130 to the blender 110. Thus, the second container 130 and the blender 110 are selectively in fluid communication. Depending on the situation, the valve 132 can be operated to allow the second fluid to flow restrictedly from the second container 130 to the blender 110 (e.g., the valve 132 can be "partially" closed or "partially" open). The valve 132 can be operated manually or via a controller further described herein. In other examples (not shown), the second container 130 is connected to the blender 110 via a pump for pumping the second fluid from the second container 130 to the blender 110.

[0115] In an example, the second container 130 contains a second fluid, such as an additive package, initial cylinder oil, or at least partially used cylinder oil (e.g., cylinder oil that has been delivered to the cylinder for lubricating the piston and cylinder liner and subsequently collected).

[0116] In the case where the second fluid is an additive package, the second container 130 is a storage tank for storing the additive package. The additive package typically contains a base oil and one or more additives, such as highly alkaline and / or neutral detergents (alkali metal salts) and optional other performance additives. The additive package typically has a high kinematic viscosity (often 50 to 200 mm² / s at 100°C, such as 100 mm² / s or greater) and a high BN (often 150 to 400).

[0117] When the second fluid is initial cylinder oil (e.g., cylinder oil that has not yet been used to lubricate the piston and cylinder liner), the second container 130 is a reservoir for storing cylinder oil. Initial cylinder oil typically has a kinematic viscosity of 16 to 21 mm² / s and a BN of 15 to 145.

[0118] When the second fluid is used cylinder oil (e.g., cylinder oil that has been used at some point to lubricate the piston and cylinder head gasket), the second container 130 is, in some instances, a reservoir for storing the used cylinder oil. In other instances, alternatively or additionally, the used cylinder oil is supplied directly from the cylinder to the blender. In this case, the second container 130 is the cylinder of the engine.

[0119] Device 10 includes a controller 140 for controlling device 10. Controller 140 includes memory and one or more processors. The memory circuitry is configured to store machine-readable instructions that, when executed by the one or more processors, cause the controller to perform the methods described herein. In an example, controller 140 is communicatively connected to and used to control each of the following: a first valve 122 for controlling the flow of a first fluid from a first container 120 to a blender 110; a second valve 132 for controlling the flow of a second fluid from a second container 130 to a blender 110; and blender 110. In some examples, some or all of these elements are controlled by an entity other than controller 140.

[0120] Controller 140 is configured to determine the ratio of fluids required to supply cylinder oil. For example, controller 140 is configured to determine the ratio of a first fluid and a second fluid, which corresponds to the amounts of the first and second fluids to be supplied to blender 110 to supply cylinder oil. Therefore, controller 140 is configured to control first valve 122 to supply a controlled amount of the first fluid to blender 110 according to the determined ratio, and to control second valve 132 to supply a controlled amount of the second fluid to blender 110 according to the determined ratio. This ratio is typically a mass ratio (and therefore controller 140 is configured to determine the mass of the first fluid and the mass of the second fluid to be supplied to blender 110), but in some cases it may be a volume ratio (and therefore controller 140 is configured to determine the volume of the first fluid and the volume of the second fluid to be supplied to blender 110).

[0121] In one example, the controller 140 is configured to determine the fluid ratio based on data received from one or more other entities (not shown). In some examples, the controller 140 is configured to receive data from one or more user input devices (not shown) to which the user has provided information such as a target kinematic viscosity. Upon receiving data indicating the target kinematic viscosity, the controller 140 is configured to determine, for example, based on data from a lookup table stored in the controller 140's memory (e.g., information containing kinematic viscosity and / or viscosity index of the first and second fluids) and / or based on an algorithmic equation stored in the controller 140's memory, the fluid ratio required to provide cylinder oil with the target viscosity. In other examples, the controller is configured to receive data indicating engine condition parameters or engine operating parameters, which will be described in more detail with reference to FIG3. In other examples, the controller is configured to receive data indicating fluid condition parameters of the first fluid, the second fluid, the produced cylinder oil, or any combination thereof. For example, the controller is configured to receive data indicating the kinematic viscosity, basicity (BN), and / or temperature of a first fluid, a second fluid, the cylinder oil being produced, or any combination thereof.

[0122] The controller 140 is configured to determine the amount of the first fluid and the amount of the second fluid supplied to the blender 110 for providing cylinder oil with a target kinematic viscosity equal to or less than 14 mm2 / s.

[0123] Figure 3 shows a schematic diagram of an apparatus 20 for preparing cylinder oil according to another example. Some components of the apparatus 20 shown in Figure 3 correspond to the components described with respect to Figure 2, in which case the reference symbols are enlarged by 100 from the reference symbols used in Figure 2.

[0124] Generally, the device 20 includes: a blender 210 for blending fluids to provide cylinder oil; a first container 220 for containing a first fluid having a first kinematic viscosity and a first BN, the first container 220 being selectively in fluid communication with the blender 210; a second container 230 for containing a second fluid having a second kinematic viscosity and a second BN, the second container 230 being selectively in fluid communication with the blender 210; a third container 250 for containing a third fluid having a third kinematic viscosity and a third BN, the third container 250 being selectively in fluid communication with the blender 210; and a controller 240 configured to determine the amount of the first fluid, the amount of the second fluid, and the amount of the third fluid supplied to the blender 210 for providing cylinder oil having a desired target viscosity and / or a target BN, the target kinematic viscosity being equal to or less than 14 mm² / s.

[0125] More precisely, the apparatus 20 includes one or more pumps for pumping fluid through the system. These pumps may take any suitable form. The pumps are provided, as appropriate, with corresponding valves (not shown) for controlling the fluid flow rate. In the absence of such valves, the pumps are used for selective fluid communication between components of the apparatus, such as selective fluid communication between each of the containers 220, 230, 250 and the blender 210, because the pumps control the flow of fluid from each of the containers 220, 230, 250 to the blender 210. Although in some instances, flow or backflow may exist through the valves when not in operation (e.g., when the pumps are not pumping), such flow or backflow is small enough that it does not substantially affect the amount of fluid supplied to the blender 210. Therefore, each of the containers 220, 230, 250 is selectively in fluid communication with the blender 210.

[0126] In this example, device 20 includes a pump 222 for pumping a first fluid from a first container 220 to a blender 210. Pump 222 is selectively controlled by a controller 240, which is further described herein. The first container 20 corresponds to the first container of device 10 depicted in FIG. 2 and is adapted as needed to operate in the device according to the example depicted in FIG. 3.

[0127] The apparatus 20 includes a pump 232 for pumping a second fluid from the second container 230 to the blender 210. The pump 232 is selectively controlled by a controller 240, which is further described herein. The second container 230 corresponds to the second container 130 of the apparatus 10 depicted in FIG. 2 and is adapted as needed to operate in the apparatus according to the example depicted in FIG. 3.

[0128] The apparatus 20 includes a pump 252 for pumping a third fluid from the third container 250 to the blender. The pump 232 is selectively controlled by a controller 240, which is further described herein.

[0129] In an example, the third container 250 contains a third fluid, such as a base oil. The base oil is typically suitable for combination with other components to provide a lubricating product. The base oil typically has a kinematic viscosity of 4 to 7 mm² / s. The third container 250 is typically a reservoir for storing the base oil. In an example, the base oil is an initial base oil (e.g., not yet used for lubricating machine components). In other examples, the base oil is a used or recycled base oil (e.g., already used for lubricating machine components, where additives and / or contaminants have been removed before supplying it to the blender 210).

[0130] In some instances (not shown), pump 222 for pumping the first fluid and / or pump 232 for pumping the second fluid and / or pump 252 for pumping the third fluid are omitted. For example, these pumps will be replaced by valves, and the first fluid and / or the second fluid and / or the third fluid will flow to the blender 210 under the influence of gravity or by means of another pump of the device 20.

[0131] In other examples (not shown), instead of each of the containers 220, 230, 250 being connected to the blender 210 via a corresponding pump, each of the containers 220, 230, 250 is connected to the blender 210 via a pump that is selectively connected and disconnected from each of the containers 220, 230, 250, and this pump is fluidly connected to one inlet of the blender 210. In operation, for example, the pump is connected to the first container 220 and disconnected from the second container 230 and the third container 250, and pumps a certain amount of first fluid from the first container 220 to the blender 210. Subsequently, the pump is disconnected from the first container 220 and connected to the second container 230, and pumps a certain amount of second fluid from the second container 230 to the blender 210. Subsequently, the pump is disconnected from the second container 230 and connected to the third container 250, and pumps a certain amount of third fluid from the third container 250 to the blender 210.

[0132] As illustrated in Figure 2, device 20 includes a controller 240 for controlling device 20.

[0133] The controller 240 includes an algorithm that determines the desired proportions of a first fluid (e.g., system oil), a second fluid (e.g., an additive package), and a third fluid (base oil), such that the cylinder oil prepared in the blender 210 has a kinematic viscosity within a target kinematic viscosity range. For example, the controller 240 includes a non-transitory computer-readable medium storing instructions that, when executed by a processor (not shown) of the controller 240, cause the processor to determine the desired proportions of the first, second, and third fluids to provide the prepared cylinder oil having a kinematic viscosity within the target kinematic viscosity range.

[0134] The controller 240 is configured to control the blender 210 and pumps 222, 232, and 252 to deliver appropriate amounts of corresponding fluids to the blender 210. For example, the controller 240 is configured to operate each pump for a period of time so that an appropriate amount of fluid is supplied to the blender 210 according to the required proportion of fluid determined by the controller 240.

[0135] In an example, the controller 240 is configured to recalculate the ratio of fluids used to provide a second cylinder oil with a different viscosity and / or BN. For example, after blending the first cylinder oil, after the controller 240 receives data indicating changes in cylinder head gasket temperature and / or changes in fuel sulfur content and / or data from an input data generator (such as a user input device or sensor), the controller 240 is configured to determine the required ratio of the first fluid, the second fluid, and (optionally) the third fluid, resulting in the second cylinder oil having a suitable kinematic viscosity and / or a suitable BN for lubricating the cylinder head gasket under varying conditions, with a kinematic viscosity and / or BN different from that of the first cylinder oil.

[0136] Controller 240 receives data from one or more input data generators indicating information about the engine, for use in generating data indicating information about the engine. In one example, at least some of the data is provided by one or more sensors for detecting parameters. In another example, at least some of the data is provided from memory containing information provided by the user, for example, by inputting data using a user input device provided as part of a user interface (not shown). In another example, at least some of the data is obtained from a lookup table contained in the memory of controller 240.

[0137] Controller 240 is communicatively connected to one or more input data generators in input data generator array 280 and is used to receive data from the one or more input data generators. Each input data generator provides data to controller 240, the data indicating engine operating parameters and / or engine condition parameters. Typically, each input data generator is a sensor for sensing engine operating parameters or engine condition parameters (or parameters indicating such parameters), or a memory containing data indicating engine operating parameters or engine condition parameters. For example, the input data generator may include memory in which data indicating parameters that can be transmitted to controller 240 has been input (e.g., sulfur content fuel is supplied to engine 4). The input data generator or controller 240 typically determines the engine operating parameters or engine condition parameters based on memory and a lookup table stored in controller 240 or data received from the input data generator.

[0138] In Figure 3, the input data generator array 280 includes: an input data generator 282 for generating data indicating the sulfur content of the fuel; an input data generator 284 for generating data indicating the engine load of the engine 4; an input data generator 286 for generating data indicating the engine speed of the engine 4; an input data generator 288 for generating data indicating the relative humidity of the air in the cylinder; an input data generator 290 for generating data indicating the amount of iron wear emissions from the cylinder; an input data generator 292 for generating data indicating the amount of residual lubricant (BN) in the cylinder; and an input data generator 294 for generating data indicating the temperature of the cylinder oil gasket. In an example, one or more of these input data generators are user input devices included in a user interface.

[0139] In an example, the data input generator is a sensor for sensing engine operating parameters or engine condition parameters and generating data indicating such parameters, or a sensor for sensing parameters related to engine operating parameters or engine condition parameters, and the sensor and / or controller 240 determines the engine operating parameters or engine condition parameters based on such parameters. For example, the input data generator 282 for generating data indicating the sulfur content of the fuel is a fuel sensor (e.g., an online or offline X-ray fluorescence oil sulfur analyzer) for sensing the properties of the fuel oil to be supplied to the engine 4 (such as, for example, the sulfur content of the fuel oil); the input data generator 288 for generating data indicating relative air humidity is a hygrometer disposed in or near the cylinder of the engine 4 for sensing relative air humidity; the input data generator 290 for generating data indicating the amount of iron wear emissions from the cylinder is a magnetometer configured to detect the amount of iron wear emissions from the cylinder; the input data generator 292 for generating data indicating the amount of cylinder lubricant residue BN is an infrared spectrometer configured to analyze the cylinder oil in the cylinder; and the input data generator 294 for generating data indicating the cylinder oil gasket temperature is a temperature sensor disposed in or near the cylinder of the engine 4 for sensing temperature, such as a thermometer, thermocouple, thermal resistor, or the like.

[0140] In other instances, controller 240 is communicatively connected to any combination of the input data generators described above and is used to receive data from any combination of the input data generators described above.

[0141] In other examples (not shown), the controller 240 is configured to receive data indicating fluid condition parameters relating to system oil, additive packages, base oil, produced cylinder oil, or any combination thereof. The controller 240 is communicatively connected to one or more input data generators indicating the fluid condition parameters and is used to receive data from those input data generators. Typically, each input data generator is a sensor for sensing the fluid condition parameter (or a parameter indicating the parameter) or a memory containing information about the fluid condition parameter.

[0142] Fluid condition parameters include the fluid's kinematic viscosity, alkalinity (BN), and / or temperature. In an example, the input data generator for generating data indicating kinematic viscosity is a viscosity sensor configured to detect the fluid's kinematic viscosity; the input data generator for generating data indicating alkalinity is an infrared spectrometer configured to detect the fluid's alkalinity; and the input data generator for generating data indicating fluid temperature is a temperature sensor, such as a thermometer, thermocouple, thermal resistor, or the like, disposed in or near the fluid for sensing temperature.

[0143] In this example, the controller 240 is configured to obtain or determine the target BN of the first cylinder oil and / or the second cylinder oil. The controller 240 is configured to receive information (e.g., data indicating the sulfur content of the fuel from the input data generator 282) and determine the target BN according to a lookup table stored in the memory of the controller 240 or by using an algorithm stored in the memory of the controller 240.

[0144] The blender 210 is optionally in fluid communication with a storage tank 260 for storing the cylinder oil prepared in the blender. The storage tank 260 is, for example, a day tank. A pump 212 is disposed between the blender 210 and the storage tank 260 for pumping the prepared cylinder oil to the storage tank 260. A controller 240 is configured to selectively cause the pump 212 to pump the prepared cylinder oil from the blender 210 to the storage tank 260. In other embodiments, the controller 240 is not communicatively connected to the pump 212, but is instead controlled by a separate controller.

[0145] The reservoir 260 is optionally in fluid communication with the cylinder head gasket 270 of the engine 4. A pump 262 is disposed between the reservoir 260 and the cylinder head gasket 270 for pumping stored cylinder oil from the reservoir 260 to the cylinder head gasket 270. In the example of FIG3, the pump 262 is controlled by a controller that is not part of the blending device 20. In other examples (not shown), the controller 240 of the blending device 20 is configured to selectively cause the pump 262 to pump stored cylinder oil from the reservoir 260 to the cylinder head gasket 270.

[0146] In other examples (not shown), the storage tank 260 is omitted, and the mixer 210 is fluidly connected to the cylinder liner 270 via a pump, so that the prepared fluid is directly supplied from the mixer 210 to the cylinder liner 270.

[0147] Figure 4 shows a flowchart illustrating a method according to an embodiment for producing cylinder oils with one or more varying kinematic viscosities for marine reciprocating internal combustion engines. Method 30 includes: providing 310 a first fluid having a first kinematic viscosity and a first BN; providing 320 a second fluid having a second kinematic viscosity and a second BN, the second kinematic viscosity being different from the first kinematic viscosity; and 330 blending the first fluid and the second fluid at a first ratio to produce a first cylinder oil having a kinematic viscosity equal to or less than 14 mm² / s at 100°C. In an example, method 30 of Figure 4 is carried out using the equipment described above.

[0148] The blending ratio of 330 depends on the amount of the first fluid supplied to blenders 110 and 210 and the amount of the second fluid supplied to blenders 110 and 210.

[0149] The provision 310 of the first fluid typically comprises a controlled amount of first fluid provided from a first container 120, 220 containing a first fluid such as system oil. This controlled amount corresponds to the quantity of first fluid required to blend the fluids at the first ratio. In some instances, the provision 310 is controlled by controllers 140, 240, which, for example, cause a pump to pump the quantity of first fluid from the first container 120, 220 to the blender 110, 210. In other instances, the provision 310 is manually controlled, for example, by an operator operating valve 122 or pump 222 to provide the controlled amount to the blender 110, 210.

[0150] The provision of the second fluid 320 typically includes providing a controlled amount of the second fluid from a second container 130, 230 containing, for example, an additive package. This controlled amount corresponds to the quantity of the second fluid required to blend the fluids at the first ratio. In one example, the provision of 320 is controlled by controllers 140, 240, for example, controllers 140, 240 causing a pump to pump this quantity of the second fluid from the second container 130, 230 to the blender 110, 210. In other examples, the provision of 320 is manually controlled, for example, by an operator operating valve 132 or pump 232 to provide the controlled amount to the blender 110, 210.

[0151] The blenders 110 and 210 have received controlled amounts of the first fluid and the second fluid, and the blending 330 includes operating the blenders 110 and 210 to mix the fluids at the first ratio, thereby providing a first cylinder oil having a viscosity equal to or less than 14 mm² / s at 100°C.

[0152] Figure 5 shows a flowchart illustrating another example of a method 40 for producing cylinder oils with one or more varying kinematic viscosities. The method 40 depicted in Figure 5 can be implemented using, for example, the apparatus depicted in Figure 3. Method 40 includes determining 410 a target kinematic viscosity of the first cylinder oil based on an engine operating parameter and / or an engine condition parameter. For example, the method includes controllers 140, 240 (e.g., any one of the input data generators in the input data generator array 280) receiving data indicating engine operating parameters and / or engine condition parameters, determining the parameters as appropriate based on the data and a lookup table contained in the memory of controllers 140, 240, and determining the target kinematic viscosity of the first cylinder oil based on the parameters. In an example, the target kinematic viscosity of the first cylinder oil is 14 mm² / s or less.

[0153] The method further includes determining 420 a target ratio range of the first fluid and the second fluid based on a set of parameters including at least the viscosity of the first fluid, the viscosity of the second fluid, and the viscosity of the third fluid, the target ratio range corresponding to the target kinematic viscosity of the first cylinder oil. Controllers 140 and 240 typically store the kinematic viscosities of at least the first fluid, the second fluid, and the third fluid in their memory. In an example, determination 420 includes controllers 110 and 210 determining the target ratio range of the first fluid and the second fluid based on the kinematic viscosities of the first fluid, the second fluid, and the third fluid in their memory and lookup tables. Typically, determining the target ratio range includes determining the range of the amount of the first fluid supplied to blenders 110 and 210, and determining the range of the amount of the second fluid supplied to blenders 110 and 210. Where appropriate, the determination also includes determining the range of the amount of the third fluid supplied to blenders 110 and 210.

[0154] The method further includes determining 430 a target ratio range of the first fluid and the second fluid based on a parameter set including at least the BN of the first fluid, the BN of the second fluid, and the BN of the third fluid, the target ratio range corresponding to the target BN of the first cylinder oil. Controllers 140 and 240 typically store at least the BNs of the first fluid, the second fluid, and the third fluid in their memory. In an example, determination 430 includes controllers 110 and 210 determining the target ratio range of the first fluid and the second fluid based on the BNs of the first fluid, the second fluid, and the third fluid in their memory and lookup tables. Typically, determining the target ratio range includes determining a range of the amount of the first fluid supplied to blenders 110 and 210, and determining a range of the amount of the second fluid supplied to blenders 110 and 210. Where appropriate, the determination may also include determining a range of the amount of the third fluid supplied to blenders 110 and 210.

[0155] Method 40 further includes providing the first fluid, the second fluid, and the third fluid to the blenders 110 and 210 at a ratio 440, the ratio being set within a target ratio range corresponding to the target kinematic viscosity and / or the target BN of the cylinder oil. Typically, providing at this ratio 440 includes providing controlled amounts of the first fluid, the second fluid, and the third fluid to the blenders 110 and 210 such that once the fluids are provided to the blenders 110 and 210, the blenders 110 and 210 contain the fluids at the ratio.

[0156] Method 40 further includes performing blending 450 such that the cylinder oil has a kinematic viscosity equal to or less than 14 mm² / s.

[0157] Figure 6 shows a flowchart illustrating a method 50 for operating a marine reciprocating internal combustion engine. Method 50 includes producing a cylinder oil 510. Producing the cylinder oil 510 includes performing any of the methods described above such that the produced cylinder oil has a kinematic viscosity equal to or less than 14 mm² / s at 100°C. Method 50 further includes supplying the produced cylinder oil 520 to a cylinder of the marine reciprocating internal combustion engine, for example, to a cylinder gasket. This supply typically includes pumping the produced cylinder oil from a reservoir 260 (e.g., a day tank) to a cylinder gasket 270. Example

[0158] The 12RT-flex96C-B engine with a power of 61776kW was operated for 53,267 hours at an average engine load of 10% of the maximum continuous power, including the operating period at 30% of the maximum continuous power.

[0159] The engine first operates for a first period of time using cylinder oil with a kinematic viscosity of 16.2 mm2 / s ("reference cylinder oil") to provide a baseline date corresponding to the known cylinder oil.

[0160] Subsequently, cylinder oils having the viscosity described in Table 1 are produced on board and supplied to the cylinder liners of the engine during operation.

[0161]

[0162] After the engine has been running with the above-mentioned cylinder oil, the cylinder head gasket was evaluated for wear, adhesive wear, and corrosive wear. The evaluation results are shown in Table 2.

[0163]

[0164] As shown in Table 2, the use of cylinder oil with reduced viscosity to operate the engine during the second period did not result in any increase in wear of the cylinder head gasket or piston rings.

[0165] Fuel consumption was calculated using reference cylinder oil in the first operating period and using cylinder oil with reduced kinematic viscosity in the second operating period. Fuel consumption in the second operating period was 2 g / kWh lower than in the first period, corresponding to a 1% reduction in fuel consumption.

[0166] In other embodiments, two or more of the above embodiments may be combined. In other embodiments, a feature of one embodiment may be combined with features of one or more other embodiments.

[0167] Embodiments of the present invention have been discussed with particular reference to the described examples. However, it will be understood that variations and modifications may be made to the examples within the scope of the present invention.

Claims

1. A method for producing cylinder oil with one or more varying kinematic viscosities for a marine reciprocating internal combustion engine, the method comprising: providing a first fluid having a first kinematic viscosity and a first base number (BN); providing a second fluid having a second kinematic viscosity and a second BN, the second kinematic viscosity being different from the first kinematic viscosity; and blending the first fluid and the second fluid in a first ratio to produce a first cylinder oil having a kinematic viscosity of 8 to 13.5 mm² / s at 100°C.

2. The method of claim 1, the method comprising: determining a target kinematic viscosity of the first cylinder oil based on an engine operating parameter and / or an engine condition parameter; determining a target ratio range of the first fluid and the second fluid based on a parameter set including the first kinematic viscosity and the second kinematic viscosity, the target ratio range corresponding to the target kinematic viscosity of the first cylinder oil; and performing the mixing of the first fluid and the second fluid such that the first ratio is set within the target ratio range corresponding to the target kinematic viscosity of the first cylinder oil.

3. The method of claim 1 or claim 2, wherein the blending comprises blending a third fluid having a third kinematic viscosity and a third BN with the first fluid and the second fluid to produce the first cylinder oil.

4. The method of claim 3, the method comprising: determining a target BN of the first cylinder oil based on an engine operating parameter and / or an engine condition parameter; determining a target ratio range of the first fluid and the second fluid based on a parameter set including at least the first BN, the second BN and the third BN, the target ratio range corresponding to the target BN of the first cylinder oil; and performing the blending such that the first ratio is set within the target ratio corresponding to the target BN of the first cylinder oil.

5. The method of claim 1 or 2, further comprising producing a second cylinder oil by blending the first fluid and the second fluid at a second ratio different from the first ratio, the second cylinder oil having a kinematic viscosity greater than that of the first cylinder oil.

6. The method of claim 5, wherein the first cylinder oil has a BN different from that of the second cylinder oil.

7. The method of claim 2, wherein the engine operating parameter or the engine condition parameter is at least one of the following: fuel sulfur content; engine load; engine speed; relative air humidity; cylinder iron wear emissions; total iron cylinder lubricant residue (BN); and cylinder oil gasket temperature.

8. As in request item 3, where: The first fluid is a system oil; and / or the second fluid is an additive package, new cylinder oil, or used cylinder oil; and / or the third fluid is a base oil.

9. The method of claim 3, wherein at least one of the first fluid, the second fluid, or the third fluid is at least partially used oil.

10. A method of operating a marine reciprocating internal combustion engine, the method comprising: producing a cylinder oil by any one of claims 1 to 9, the cylinder oil having a kinematic viscosity of 8 to 13.5 mm² / s at 100°C; and supplying the cylinder oil to a cylinder of the marine reciprocating internal combustion engine.

11. The method of claim 10, wherein the kinematic viscosity of the cylinder oil is lower than the minimum cylinder oil kinematic viscosity recommended by the manufacturer for the marine reciprocating internal combustion engine.

12. The method of claim 10 or claim 11, wherein the ship uses a reciprocating internal combustion engine operating at 60% or less of the engine load.

13. The method of any one of claims 1, 2, 7, 10 and 11, wherein the reciprocating internal combustion engine used on the vessel is a one- or two-stroke crosshead engine.

14. The method of any one of claims 1, 2, 7, 10 and 11, wherein the first cylinder oil has a kinematic viscosity of 8 to equal to or less than 12.5 mm² / s at 100°C.

15. An apparatus for preparing a cylinder oil, the apparatus comprising: a blender; a first container for containing a first fluid having a first kinematic viscosity and a first BN, the first container being selectively fluid-communicated with the blender; a second container for containing a second fluid having a second kinematic viscosity and a second BN, the second container being selectively fluid-communicated with the blender; and a controller configured to determine the amount of the first fluid and the amount of the second fluid supplied to the blender for providing a cylinder oil having a desired target viscosity and a target BN, the target kinematic viscosity being 8 to 13.5 mm² / s at 100°C.

16. A marine vessel comprising the equipment as claimed in claim 15.

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