Method for determination

Abstract

To determine in advance the suitability of a combination of fuel oil and lubricating oil.SOLUTION: The method for determining the suitability of a combination of fuel oil and lubricating oil includes: a mixing step S120 of mixing a solid contained in incomplete-combustion products of the fuel oil with the lubricating oil; a heating step S130 of heating a solid-liquid mixture of the solid and the lubricating oil at a first temperature; and a first determination step S160 of determining the suitability of the combination of the fuel oil and the lubricating oil on the basis of a change in mass of the solid in the solid-liquid mixture caused by the heating at the first temperature.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a determination method. [Background technology]

[0002] When engine lubricating oil deteriorates and solid impurities are generated in the lubricating oil, problems arise in that damage such as scuffing occurs.

[0003] Therefore, a technology has been developed in which lubricating oil is sampled from an engine while it is running, and sulfuric acid is added to the sampled lubricating oil to detect the deterioration state of the lubricating oil (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-137342 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the causes of solid contaminants is thought to be the mixing of fuel oil with lubricating oil in the engine combustion chamber, etc. For this reason, there is a need for technology that can determine in advance whether a fuel oil and lubricating oil combination is suitable.

[0006] In view of the above problems, the present disclosure aims to provide a method for determining in advance whether a combination of fuel oil and lubricating oil is suitable. [Means for solving the problem]

[0007] In order to solve the above problem, a determination method according to one embodiment of the present disclosure includes a mixing step of mixing solid matter among the products of incomplete combustion of fuel oil with a lubricating oil, a heating step of heating the solid-liquid mixture of the solid matter and the lubricating oil at a first temperature, and a first determination step of determining the suitability of the combination of fuel oil and lubricating oil based on the change in mass of the solid matter in the solid-liquid mixture due to heating at the first temperature.

[0008] In addition, the above determination method may further include a solid generation process in which the fuel oil is heated at a second temperature higher than the first temperature to generate solids, and in the mixing process, the solids generated in the solid generation process may be mixed with the lubricating oil.

[0009] The determination method may further include a collection step of collecting solid matter from the combustion chamber of the engine, and in the mixing step, the solid matter collected in the collection step may be mixed with the lubricating oil.

[0010] In addition, the above-mentioned determination method may further include a second determination step of determining the suitability of the combination of fuel oil and lubricating oil based on the change in concentration of carboxyl groups contained in the liquid in the solid-liquid mixture due to heating at the first temperature.

[0011] The first temperature may be 100°C or higher and 400°C or lower.

[0012] The second temperature may be 300°C or higher and 2000°C or lower. [Effects of the Invention]

[0013] According to the present disclosure, it is possible to determine in advance whether a combination of fuel oil and lubricating oil is appropriate. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a determination system according to the first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the general configuration of the solid material generating apparatus and the mixer according to the first embodiment. [Figure 3] FIG. 3 is a flowchart showing the flow of processing of the determination method according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a schematic configuration of a determination system according to the second embodiment. [Figure 5] FIG. 5 is a flowchart showing the flow of processing of the determination method according to the second embodiment. [Figure 6] FIG. 6 is a schematic diagram showing a schematic configuration of a determination system according to the third embodiment. [Figure 7] FIG. 7 is a first flowchart showing the flow of processing of the determination method according to the third embodiment. [Figure 8] FIG. 8 is a second flowchart showing the processing flow of the determination method according to the third embodiment. [Figure 9] FIG. 9 is a graph showing the change in the amount of solid in the solid-liquid mixture due to heating at the first temperature in Example 1, Example 2, and the comparative example. [Figure 10] FIG. 10 is a graph showing the change in the amount of carboxyl groups contained in the liquid in the solid-liquid mixture due to heating at the first temperature in Example 1, Example 2, and the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present disclosure are not shown.

[0016] [First embodiment] <Determination system 100> Fig. 1 is a schematic diagram showing the general configuration of a determination system 100 according to the first embodiment. Fig. 2 is a schematic diagram showing the general configuration of a solid product generation apparatus 110 and a mixing apparatus 130 according to the first embodiment. As shown in Fig. 1, the determination system 100 according to the first embodiment includes the solid product generation apparatus 110, a measuring apparatus 120, a mixing apparatus 130, a heating apparatus 140, a separating apparatus 150, and a control apparatus 160.

[0017] The solids generator 110 heats the fuel oil to generate solids from the incomplete combustion products of the fuel oil. In other words, the solids are solids generated by the incomplete combustion of the fuel oil. The solids include either or both of oxidative degradation products of the fuel oil and thermal degradation products of the fuel oil.

[0018] As shown in FIG. 2, the solid production apparatus 110 includes, for example, a fuel oil supply section 210, a gas cylinder 220, a gas delivery pipe 222, a flow meter 224, a production section 230, a heating furnace 240, an exhaust pipe 242, and a condenser 250.

[0019] The fuel oil supply unit 210 supplies fuel oil to the production unit 230. The fuel oil supply unit 210 includes, for example, a cylinder 212, two pistons 214, a fuel oil supply pipe 216, and a fuel oil delivery pipe 218.

[0020] A thread is formed on the inner periphery of the cylinder 212. A thread is formed on the outer periphery of the piston 214 so as to be threadably engaged with the inner periphery of the cylinder 212. The two pistons 214 are inserted into the cylinder 212 from both sides thereof.

[0021] The fuel oil supply pipe 216 is connected to the inside of the cylinder 212. Fuel oil is supplied into the cylinder 212 through the fuel oil supply pipe 216. An on-off valve 216a is provided in the fuel oil supply pipe 216.

[0022] The fuel oil delivery pipe 218 connects the inside of the cylinder 212 with the generation section 230. When the piston 214 is rotated by an actuator (not shown), the fuel oil stored in the cylinder 212 is supplied to the generation section 230 through the fuel oil delivery pipe 218.

[0023] The fuel oil supply unit 210 may further include a heater that heats the cylinder 212. This can reduce the viscosity of the fuel oil, making it easier to supply the fuel oil to the production unit 230.

[0024] The gas cylinder 220 stores a first atmospheric gas, which will be described later.

[0025] Gas delivery pipe 222 connects gas cylinder 220 and generation unit 230. Flow meter 224 is provided in gas delivery pipe 222. Flow meter 224 measures the flow rate of the first ambient gas supplied to generation unit 230. In addition, an on-off valve 222a is provided in gas delivery pipe 222 between flow meter 224 and generation unit 230.

[0026] The generation section 230 is provided in the heating furnace 240. As described above, the generation section 230 is supplied with fuel oil and a first atmospheric gas. The generation section 230 is, for example, a metal pipe. The generation section 230 may also be provided with fins (not shown). This makes it possible to suppress a decrease in temperature of the generation section 230.

[0027] The heating furnace 240 heats the generating unit 230 to a second temperature. The heating furnace 240 is, for example, an electric furnace. The second temperature will be described later.

[0028] In the generation section 230, the fuel oil and the first atmospheric gas are heated at the second temperature, and an oxidative degradation product of the fuel oil and a thermal degradation product of the fuel oil are generated. Note that the oxidative degradation product of the fuel oil and the thermal degradation product of the fuel oil generated in the generation section 230 are gaseous.

[0029] Exhaust pipe 242 connects generation section 230 and condenser 250. Oxidative degradation products of fuel oil and thermal degradation products of fuel oil generated in generation section 230 are supplied to condenser 250 through exhaust pipe 242. Exhaust pipe 242 is provided with check valve 242a. Check valve 242a prevents backflow from condenser 250 to generation section 230.

[0030] The condenser 250 cools the oxidative degradation products of the gaseous fuel oil and the thermal degradation products of the fuel oil. As a result, the oxidative degradation products of the gaseous fuel oil and the thermal degradation products of the fuel oil are condensed to produce solid fuel oil. The condenser 250 is detachable from the circulation path 260, which will be described later.

[0031] Returning to FIG. 1 , the measuring device 120 measures the mass Dw of the fuel oil solids generated by the solid generation device 110. For example, the measuring device 120 measures the mass of the condenser 250 before the oxidized and thermally degraded products of the gaseous fuel oil are supplied. The measuring device 120 then measures the mass of the condenser 250 after the oxidized and thermally degraded products of the gaseous fuel oil are supplied and condensed. The measuring device 120 determines the difference between these masses as the mass Dw of the fuel oil solids.

[0032] The measuring device 120 also measures the mass Sw of the solid, which will be described later.

[0033] The mixer 130 mixes the fuel oil solids produced by the solids generator 110 with the lubricating oil.

[0034] As shown in FIG. 2, the mixer 130 includes, for example, a circulation path 260, a pump 262, a gas-liquid separator 264, a gas storage section 270, and a filter 272.

[0035] The circulation path 260 is provided with a condenser 250, a pump 262, and a gas-liquid separator 264. The suction side of the pump 262 is connected to the bottom surface of the gas-liquid separator 264. The discharge side of the pump 262 is connected to the condenser 250. When the pump 262 is operated, the lubricating oil stored in the gas-liquid separator 264 is supplied to the condenser 250. Then, the lubricating oil in the condenser 250 is sent to the gas-liquid separator 264. As a result, the fuel oil solids and the lubricating oil are mixed in the condenser 250.

[0036] The gas-liquid separator 264 separates the lubricating oil sent from the condenser 250 into gas and liquid. The gas separated by the gas-liquid separator 264 is supplied to the gas storage section 270 through a filter 272.

[0037] 1, the heating device 140 heats the solid-liquid mixture of the solid material and the lubricant oil at a first temperature. The heating device 140 is, for example, an electric furnace. The first temperature will be described later.

[0038] The separation device 150 separates the solid-liquid mixture heated to the first temperature by the heating device 140 into solid and liquid. The separation device 150 includes, for example, a solvent addition unit and a filter. The solvent addition unit adds a solvent to the solid-liquid mixture. The filter filters the solid-liquid mixture after the solvent addition. This separates the solid from the solid-liquid mixture.

[0039] Furthermore, the mass Sw of the solid matter separated by the separator 150 is measured by the measuring device 120.

[0040] The control device 160 includes a central control unit 162 and a memory 164 .

[0041] The central control unit 162 is configured, for example, by a semiconductor integrated circuit including a CPU (Central Processing Unit). The central control unit 162 reads programs and parameters for operating the CPU from the ROM. The central control unit 162 manages and controls the entire determination system 100 in cooperation with RAM as a work area and other electronic circuits.

[0042] The memory 164 is configured with, for example, a ROM, a RAM, a flash memory, a HDD, etc. The memory 164 stores programs and various data used by the central control unit 162. The memory 164 stores, for example, a first threshold value Th1. The first threshold value Th1 will be described later.

[0043] <Judgment method> Fig. 3 is a flowchart showing the process flow of the determination method according to the first embodiment. As shown in Fig. 3, the determination method according to the first embodiment includes a solid matter generating step S110, a mixing step S120, a heating step S130, a separating step S140, a first measuring step S150, and a first determining step S160. Each step will be described below.

[0044] [Solid production step S110] In the solid generation step S110, the fuel oil is heated to generate solids from the incomplete combustion products of the fuel oil. The solid generation step S110 is performed using the solid generation device 110, for example.

[0045] The heating temperature (second temperature) in the solid generation step S110 is higher than the heating temperature (first temperature) in the heating step S130, which will be described later. The second temperature may be a temperature that satisfies the combustion conditions in the combustion chamber of the engine. The second temperature is, for example, 300°C or higher and 2000°C or lower.

[0046] In the solid generation step S110, the fuel oil may be heated in a first atmospheric gas under a first pressure. The first atmospheric gas is, for example, an atmospheric gas when incomplete combustion occurs in the combustion chamber of an engine. The first atmospheric gas is, for example, nitrogen or a gas having an oxygen concentration lower than that of air (for example, less than 21% by volume). The first pressure is the pressure in the combustion chamber of the engine.

[0047] Furthermore, in the solid production step S110, the fuel oil may be heated and gasified before being mixed with the first atmospheric gas, which makes it possible to mix the fuel oil with the first atmospheric gas uniformly.

[0048] [Mixing process S120] In the mixing step S120, the solid material generated in the solid material generating step S110 is mixed with the lubricating oil. Note that in the mixing step S120, the mass Dw of the solid material is measured, for example, by the measuring device 120, before mixing with the lubricating oil. The mixing step S120 is performed, for example, by using the mixing device 130.

[0049] [Heating process S130] In the heating step S130, the solid-liquid mixture of the solid material and the lubricant oil produced in the mixing step S120 is heated at a first temperature. The heating step S130 is performed using the heating device 140, for example.

[0050] The first temperature may be the temperature of a wall surface of a combustion chamber of an engine in operation, and is particularly preferably the temperature of a wall surface of a cylinder of the engine in operation. The wall surface of the combustion chamber of the engine refers to the wall surface of a cylinder included in the engine and the wall surface of a cylinder head. The first temperature is, for example, 100°C or higher and 400°C or lower.

[0051] In addition, in the heating step S130, the solid-liquid mixture may be heated in a second atmospheric gas and under a second pressure. The second atmospheric gas is the atmospheric gas in the combustion chamber of the engine during operation. The second atmospheric gas is, for example, air or air containing gasified fuel oil. The second pressure is the pressure in the combustion chamber of the engine during operation.

[0052] [Separation process S140] In the separation step S140, the solid-liquid mixture obtained in the heating step S130 is subjected to solid-liquid separation. The separation step S140 is performed, for example, using the separation device 150. In the separation step S140, for example, first, a solvent is added to the solid-liquid mixture, and the solid-liquid mixture after the addition of the solvent is filtered with a filter.

[0053] [First measurement step S150] In the first measuring step S150, the mass Sw of the solid separated in the separating step S140 is measured. The first measuring step S150 is performed using the measuring device 120, for example.

[0054] [First judgment step S160] In the first determination step S160, the suitability of the combination of fuel oil and lubricating oil is determined based on the change in mass of the solids in the solid-liquid mixture due to heating at the first temperature in the heating step S130. The solids in the solid-liquid mixture include, for example, solids of the fuel oil, oxidative degradation products of the lubricating oil, and thermal degradation products of the lubricating oil.

[0055] The first determination step S160 according to this embodiment includes a difference determination step S160-1, an appropriateness determination step S160-2, and an inappropriateness determination step S160-3.

[0056] [Difference determination step S160-1] In the difference determination step S160-1, for example, the central control unit 162 first calculates the difference between the mass Dw of the solid matter measured in the mixing step S120 and the mass Sw of the solid matter measured in the first measurement step S150. Then, the central control unit 162 determines whether the difference is equal to or less than a first threshold value Th1. As a result, if the central control unit 162 determines that the difference between the mass Dw of the solid matter and the mass Sw of the solid matter is equal to or less than the first threshold value Th1 (YES in S160-1), the central control unit 162 shifts the process to an appropriateness determination step S160-2. On the other hand, if the central control unit 162 determines that the difference between the mass Dw of the solid matter and the mass Sw of the solid matter is not equal to or less than the first threshold value Th1, that is, exceeds the first threshold value Th1 (NO in S160-1), the central control unit 162 shifts the process to an inappropriateness determination step S160-3.

[0057] The first threshold value Th1 is a predetermined value and is determined, for example, based on a combination of fuel oil and lubricating oil that generates only a small amount of solid matter in the lubricating oil that does not interfere with the operation (driving) of the engine.

[0058] [Appropriateness determination process S160-2] In the suitability determination step S160-2, for example, the central control unit 162 determines that the combination of fuel oil and lubricant oil is suitable.

[0059] [Inappropriateness determination process S160-3] In the inappropriateness determination step S160-3, for example, the central control unit 162 determines that the combination of fuel oil and lubricant oil is inappropriate.

[0060] <Advantages of the Determination Method According to the First Embodiment> The present inventors have discovered that the increase in solid contaminants in lubricating oil is caused by solid matter among the products of incomplete combustion of fuel oil.

[0061] Therefore, the determination method according to this embodiment heats a solid-liquid mixture of fuel oil solids and lubricating oil at a first temperature, and determines the suitability of the combination of fuel oil and lubricating oil based on the change in mass of the solids in the solid-liquid mixture before and after heating. This allows the determination method according to this embodiment to determine the suitability of the combination of fuel oil and lubricating oil in advance before using the fuel oil and lubricating oil in an actual engine. In other words, the determination method according to this embodiment can determine in advance an appropriate combination of fuel oil and lubricating oil that will produce an amount of solid contaminants in the lubricating oil that is equal to or less than the first threshold value Th1.

[0062] For example, in a ship, the type and quality of fuel oil that can be refueled may differ depending on the port of call. The determination method according to this embodiment can determine the suitability of combinations of various fuel oils and lubricating oils before refueling, so it can determine whether the fuel oil is suitable for the lubricating oil used in the ship's engine before refueling.

[0063] Furthermore, for example, when changing lubricating oil, it is possible to determine before the change whether the combination of the fuel oil to be used and the lubricating oil to be changed is suitable, so it is possible to determine before the lubricating oil is changed whether the lubricating oil is suitable for the fuel oil stored in the tank.

[0064] As described above, the first temperature is, for example, 100°C or higher and 400°C or lower. This makes it possible to reproduce the temperature of the combustion chamber wall surface, for example, the temperature of the cylinder wall surface, during engine operation in the heating step S130. Therefore, in the heating step S130, it is possible to heat the solid-liquid mixture of the solid matter and the lubricant oil under the conditions of the combustion chamber wall surface during engine operation, without using an actual engine. Therefore, in the first determination step S160, it is possible to determine with high accuracy whether the combination of fuel oil and lubricant oil is appropriate.

[0065] As described above, the second temperature is, for example, 300°C or higher and 2000°C or lower. This makes it possible to reproduce the temperature of the combustion chamber under combustion conditions during engine operation in the solid matter generation step S110. Therefore, in the solid matter generation step S110, it is possible to generate solid matter from the incomplete combustion products of the fuel oil without using an actual engine.

[0066] [Second embodiment] <Determination system 300> Fig. 4 is a schematic diagram showing the general configuration of a determination system 300 according to the second embodiment. As shown in Fig. 4, the determination system 300 according to the second embodiment includes a collection device 310, a measurement device 120, a mixing device 130, a heating device 140, a separation device 150, and a control device 160. Note that components that are substantially the same as those in the determination system 100 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0067] The collection device 310 collects deposits from the combustion chamber of the engine. Deposits are solid matter that adheres to the combustion chamber. Deposits are solid matter that is a product of incomplete combustion of fuel oil and solid matter that is a product of incomplete combustion of lubricating oil. In other words, deposits include solid matter that is a product of incomplete combustion of fuel oil.

[0068] The measuring device 120 of the determination system 300 measures the mass Dw of the solid matter collected by the collecting device 310 and before being mixed by the mixing device 130.

[0069] Furthermore, the mixer 130 of the determination system 300 mixes the solid matter collected by the collector 310 with the fuel oil.

[0070] <Judgment method> Fig. 5 is a flowchart showing the process flow of the determination method according to the second embodiment. As shown in Fig. 5, the determination method according to the second embodiment includes a collection step S210, a mixing step S220, a heating step S130, a separation step S140, a first measurement step S150, and a first determination step S160. Note that steps that are substantially the same as those in the determination method according to the first embodiment are denoted by the same reference numerals and will not be described again. The collection step S210 and the mixing step S220 will be described below.

[0071] [Collection process S210] In the collection step S210, solid matter is collected from the combustion chamber of the engine. The collection step S210 is performed using a collection device 310, for example.

[0072] [Mixing process S220] In the mixing step S120, the solid matter collected in the collection step S210 is mixed with the lubricant. The mixing step S220 is performed using a mixer 130, for example.

[0073] As described above, the determination method according to the second embodiment determines the suitability of a combination of fuel oil and lubricating oil using solids collected from the combustion chamber of an engine that was actually in operation. This enables the determination method according to the second embodiment to determine the suitability of a combination of fuel oil and lubricating oil with higher accuracy.

[0074] [Third embodiment] <Determination System 400> Fig. 6 is a schematic diagram showing the overall configuration of a determination system 400 according to the third embodiment. As shown in Fig. 6, the determination system 400 according to the third embodiment includes a solid matter generating apparatus 110, a measuring apparatus 120, a mixing apparatus 130, a heating apparatus 140, a separating apparatus 410, an analyzing apparatus 420, and a control apparatus 160. Note that components that are substantially the same as those in the determination system 100 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0075] The separation device 410 according to the third embodiment includes, for example, a solvent adding unit, a filter, and a heating unit. The solvent adding unit adds a solvent to the solid-liquid mixture. The filter filters the solid-liquid mixture after the solvent addition. The added solvent is, for example, a solvent that can be fractionally distilled from the lubricating oil and does not contain a carboxyl group. The boiling point of the solvent is, for example, lower than that of the lubricating oil. The boiling point of the solvent is, for example, about 50°C. The heating unit heats the mixture of the lubricating oil and the solvent after the solid has been filtered out by the filter. This removes the solvent from the mixture. This allows the separation device 410 to separate the lubricating oil (liquid) from the solid-liquid mixture.

[0076] The analyzer 420 measures the concentration (for example, molar concentration [mol / L]) of carboxyl groups contained in the liquid in the solid-liquid mixture. The analyzer 420 is, for example, a Fourier transform infrared spectrometer (FT-IR). In this embodiment, the analyzer 420 measures the concentration of carboxyl groups in the lubricating oil and the concentration of carboxyl groups contained in the liquid obtained by solid-liquid separation by the separator 150. For example, the analyzer 420 measures the concentration of carboxyl groups in the 1720 to 1700 cm region of the infrared absorption spectrum. -1 Measure the corrected extinction coefficient of

[0077] Furthermore, the memory 164 of the control device 160 according to the third embodiment stores a second threshold value Th2, which will be described later.

[0078] <Judgment method> FIG. 7 is a first flowchart showing the process flow of the determination method according to the third embodiment. FIG. 8 is a second flowchart showing the process flow of the determination method according to the third embodiment. As shown in FIG. 7, the determination method according to the third embodiment includes a solid generation step S110, a mixing step S120, a heating step S130, a separation step S140, a first measurement step S150, a first determination step S460, a second measurement step S470, and a second determination step S480. Note that steps that are substantially the same as those in the determination method according to the first embodiment are denoted by the same reference numerals and will not be described again. The first determination step S460, the second measurement step S470, and the second determination step S480 will be described below.

[0079] [First judgment step S460] 7, the first determination step S460 of this embodiment includes a difference determination step S160-1 and an inappropriateness determination step S160-3. In the difference determination step S160-1, for example, the central control unit 162 first calculates the difference between the mass Dw of the solid matter measured in the mixing step S120 and the mass Sw of the solid matter measured in the first measurement step S150. The central control unit 162 then determines whether the difference is equal to or less than a first threshold value Th1. As a result, when the central control unit 162 determines that the difference between the mass Dw of the solid matter and the mass Sw of the solid matter is equal to or less than the first threshold value Th1 (YES in S160-1), the central control unit 162 proceeds to the second measurement step S470. On the other hand, if it is determined that the difference between the mass Dw of the solid matter and the mass Sw of the solid is not less than the first threshold value Th1, that is, exceeds the first threshold value Th1 (NO in S160-1), as in the first embodiment described above, the central control unit 162 transfers processing to the inappropriateness determination step S160-3.

[0080] [Second measurement process S470] In the second measuring step S470, the amount of carboxyl groups in the lubricating oil before mixing in the mixing step S120 and the amount of carboxyl groups in the liquid separated in the separation step S140 are measured. The second measuring step S470 is performed, for example, using the above-mentioned analysis device 420. For example, the above-mentioned analysis device 420 measures the amount of carboxyl groups in the lubricating oil before mixing and the liquid after separation at 1720 to 1700 cm-1 Measure the corrected extinction coefficient of

[0081] [Second judgment step S480] The second determination step S480 determines whether the combination of the fuel oil and the lubricating oil is suitable based on the amount of change in the concentration of carboxyl groups contained in the liquid in the solid-liquid mixture due to heating at the first temperature. As shown in Fig. 8, the second determination step S480 of this embodiment includes a determination step S480-1, an appropriateness determination step S480-2, and an inappropriateness determination step S480-3.

[0082] [Judgment step S480-1] In the determination step S480-1, for example, the central control unit 162 determines whether the difference DC between the concentration of carboxyl groups contained in the lubricating oil before mixing in the mixing step S120 and the concentration of carboxyl groups contained in the liquid separated in the separation step S140 is equal to or less than a second threshold value Th2. For example, the central control unit 162 determines whether the difference DC between the concentration of carboxyl groups contained in the lubricating oil before mixing in the mixing step S120 and the concentration of carboxyl groups contained in the liquid separated in the separation step S140 is equal to or less than a second threshold value Th2. -1 and the corrected extinction coefficient of the separated liquid from 1720 to 1700 cm -1 is equal to or less than the difference in the corrected extinction coefficient corresponding to the second threshold Th2. As a result, if it is determined that the difference DC is equal to or less than the second threshold Th2 (YES in S480-1), the central control unit 162 shifts the process to an appropriateness determination step S480-2. On the other hand, if it is determined that the difference DC is not equal to or less than the second threshold Th2, that is, if it is determined that the difference DC exceeds the second threshold Th2 (NO in S480-1), the central control unit 162 shifts the process to an inappropriateness determination step S480-3.

[0083] [Appropriateness determination process S480-2] In the suitability determination step S480-2, for example, the central control unit 162 determines that the combination of fuel oil and lubricant oil is suitable.

[0084] [Inappropriateness determination process S480-3] In the inappropriateness determination step S480-3, for example, the central control unit 162 determines that the combination of fuel oil and lubricant oil is inappropriate.

[0085] <Effects of the determination method according to the third embodiment> Molecules with carboxyl groups tend to solidify. Therefore, the determination method according to the third embodiment determines that the combination of fuel oil and lubricating oil is inappropriate when the concentration of carboxyl groups exceeds the second threshold value Th2, even if the amount of solids in the solid-liquid mixture is equal to or less than the first threshold value Th1. This allows the determination method according to the third embodiment to determine the suitability of the combination of fuel oil and lubricating oil with even greater accuracy. [Example]

[0086] In Example 1, VLSFO was used as the fuel oil, and a solid generation step S110, a mixing step S120, a heating step S130, a separation step S140, a first measurement step S150, and a second measurement step S470 were performed. VLSFO is heavy oil with a sulfur content of less than 0.5% by mass.

[0087] In Example 2, ULSFO was used as the fuel oil, and a solid generation step S110, a mixing step S120, a heating step S130, a separation step S140, a first measurement step S150, and a second measurement step S470 were performed. ULSFO is heavy oil with a sulfur content of less than 0.1% by mass.

[0088] In the comparative example, the solid generating step S110 and the mixing step S120 were not performed, and the heating step S130, the separating step S140, the first measuring step S150, and the second measuring step S470 were performed using only the lubricating oil.

[0089] 9 is a graph showing the change in mass of solids in a solid-liquid mixture due to heating at a first temperature in Example 1, Example 2, and Comparative Example. As shown in FIG. 9, Example 1 had an increase in solids of about 1.78 times that of the Comparative Example. Furthermore, Example 2 had an increase in solids of about 1.45 times that of the Comparative Example.

[0090] These results confirm that the solids in the fuel oil increase the solids in the lubricating oil.

[0091] 10 is a graph showing the change in the concentration of carboxyl groups contained in the liquid in the solid-liquid mixture due to heating at a first temperature in Example 1, Example 2, and Comparative Example. As shown in FIG. 10, Example 2 has a higher carboxyl group concentration in the range of 1720 to 1700 cm than Comparative Example. -1 The corrected extinction coefficient of Example 1 was larger than that of Example 2. -1 The corrected extinction coefficient of

[0092] From the above results, it was confirmed that the solid matter in the fuel oil increases the concentration of carboxyl groups contained in the lubricating oil.

[0093] Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0094] For example, in the third embodiment, the solid producing step S110 and the mixing step S120 may be replaced by the collecting step S210 and the mixing step S220. [Explanation of symbols]

[0095] 100 Judgment System 110 Solid matter generator 120 Measuring Equipment 130 Mixing equipment 140 Heating device 150 Separation equipment 160 Control device 162 Central Control Unit 164 memory 300 Judgment System 310 Collection device 400 Judgment System 410 Separation equipment 420 Analyzer

Claims

1. a mixing step of mixing solid matter from the incomplete combustion products of the fuel oil with the lubricating oil; a heating step of heating a solid-liquid mixture of the solid material and the lubricating oil at a first temperature; a first determination step of determining whether the combination of the fuel oil and the lubricating oil is suitable based on a change in mass of the solid in the solid-liquid mixture due to heating at the first temperature; A determination method including:

2. The method further includes a solids generating step of heating the fuel oil at a second temperature higher than the first temperature to generate the solids; The determination method according to claim 1 , wherein the mixing step includes mixing the solid matter produced in the solid matter producing step with the lubricating oil.

3. further comprising the step of collecting the solid matter from the combustion chamber of the engine; The determination method according to claim 1 , wherein the mixing step includes mixing the solid matter collected in the collecting step with the lubricating oil.

4. 4. The method according to claim 1, further comprising a second determination step of determining the suitability of a combination of the fuel oil and the lubricating oil based on a change in concentration of carboxyl groups contained in the liquid in the solid-liquid mixture due to heating at the first temperature.

5. The determination method according to claim 1 , wherein the first temperature is equal to or higher than 100° C. and equal to or lower than 400° C.

6. The determination method according to claim 2 , wherein the second temperature is equal to or higher than 300° C. and equal to or lower than 2000° C.

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