JP2021017862A - Lubrication oil deterioration determination device - Google Patents

Abstract

To provide a lubrication oil deterioration determination device capable of accurately determining deterioration of lubrication oil of an internal combustion engine.SOLUTION: A lubrication oil deterioration determination device includes: an oil temperature sensor 30 detecting a temperature of engine oil of an engine 2; and a control section that at start of the engine 2, determines increase amount of metal in the engine oil on the basis of the oil temperature of the engine oil at start of the engine 2, corrects the increase amount of the metal in the engine oil on the basis of a fuel dilution rate of the engine oil at start of the engine 2 and time required for starting the engine 2 and determines deterioration of the engine oil when the metal amount in the engine is a predetermined value or greater.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lubricating oil deterioration determination device.

Patent Document 1 includes an oil dilution ratio calculating means for detecting or estimating the oil dilution ratio of engine oil in an internal combustion engine that directly injects fuel into a cylinder, and the oil dilution ratio and engine oil during warm-up operation after starting the engine. It describes what determines the necessity of oil dilution suppression control based on the oil temperature.

Japanese Unexamined Patent Publication No. 2010-37992

By the way, it has been found that deterioration of engine oil is caused not only by dilution with fuel but also by mixing metal generated by wear of sliding parts of an internal combustion engine into the engine oil.

If metal is mixed in the engine oil, normal lubrication will not be possible. Therefore, it is desirable to be able to grasp the amount of metal mixed in the engine oil and judge the deterioration of the engine oil.

Therefore, an object of the present invention is to provide a lubricating oil deterioration determining device capable of accurately determining deterioration of lubricating oil of an internal combustion engine.

In order to solve the above problems, the present invention determines the amount of increase in metal in the lubricating oil based on the oil temperature of the lubricating oil of the internal combustion engine at the time of starting the internal combustion engine, and obtains the lubrication. It is provided with a control unit that determines that the lubricating oil has deteriorated when the amount of metal in the oil is equal to or greater than a predetermined value.

As described above, according to the present invention, the deterioration of the lubricating oil of the internal combustion engine can be accurately determined.

FIG. 1 is a schematic configuration diagram of a lubricating oil deterioration determination device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a procedure of iron concentration calculation processing of the lubricating oil deterioration determination device according to the embodiment of the present invention. FIG. 3 is a flowchart showing a procedure of iron concentration calculation processing of the lubricating oil deterioration determination device according to another aspect of the embodiment of the present invention.

The lubricating oil deterioration determination device according to the embodiment of the present invention determines the amount of increase in metal in the lubricating oil at the time of starting the internal combustion engine based on the oil temperature of the lubricating oil of the internal combustion engine at the time of starting the internal combustion engine. It is configured to include a control unit for determining that the lubricating oil has deteriorated when the amount of metal in the lubricating oil is equal to or greater than a predetermined value.

As a result, the lubricating oil deterioration determination device according to the embodiment of the present invention can accurately determine the deterioration of the lubricating oil of the internal combustion engine.

Hereinafter, the lubricating oil deterioration determination device according to the embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, a vehicle 1 equipped with a lubricating oil deterioration determination device according to an embodiment of the present invention includes an internal combustion engine type engine 2 and an ECU (Electronic Control Unit) 3 as a control unit. ..

The engine 2 is formed with a cylinder 5 as a cylinder. A piston 6 capable of reciprocating up and down in the cylinder 5 is housed in the cylinder 5. A combustion chamber 7 is provided above the cylinder 5.

The engine 2 is a so-called four-cycle gasoline engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston 6 reciprocates in the cylinder 5.

Further, the piston 6 is connected to the crankshaft 9 via a connecting rod 8. The connecting rod 8 converts the reciprocating motion of the piston 6 into the rotational motion of the crankshaft 9.

Further, the combustion chamber 7 is provided with a spark plug 10 and an injector 11. The spark plug 10 is arranged in the combustion chamber 7 with the electrodes protruding, and the ignition timing is adjusted by the ECU 3.

The injector 11 is a so-called in-cylinder injection type fuel injection valve that injects fuel supplied by a fuel pump from a fuel tank (not shown) into the combustion chamber 7.

The engine 2 is provided with an intake port 12 and an exhaust port 21. The intake port 12 communicates the combustion chamber 7 with the intake passage 14a described later. Further, the intake port 12 is provided with an intake valve 13.

The intake valve 13 is opened and closed so as to communicate or shut off the intake passage 14a and the combustion chamber 7.

Further, an intake pipe 14 is connected to the intake port 12. Inside the intake pipe 14, an intake passage 14a communicating with the intake port 12 is formed. An electronically controlled throttle valve 15 is provided in the intake passage 14a. The throttle valve 15 is electrically connected to the ECU 3.

The throttle valve 15 adjusts the intake air amount of the engine 2 by controlling the throttle opening degree in response to a command signal from the ECU 3.

On the other hand, the exhaust port 21 is provided with an exhaust valve 22. The exhaust valve 22 is opened and closed so as to communicate or shut off the exhaust passage 24a and the combustion chamber 7, which will be described later.

Further, an exhaust pipe 24 is connected to the exhaust port 21. An exhaust passage 24a communicating with the exhaust port 21 is formed inside the exhaust pipe 24. An air-fuel ratio sensor 25 is provided in the exhaust passage 24a.

The engine 2 configured as described above is an ignition type engine in which a mixture of intake air whose flow rate is adjusted by a throttle valve 15 and fuel injected by an injector 11 is ignited by a spark plug 10 to ignite.

The ECU 3 is composed of a computer unit including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port.

The ROM of the computer unit stores various control constants, various maps, and the like, as well as a program for making the computer unit function as the ECU 3. That is, when the CPU executes the program stored in the ROM, the computer unit functions as the ECU 3.

In addition to the air-fuel ratio sensor 25 described above, various sensors such as an engine speed sensor 26, an accelerator opening sensor 28, a water temperature sensor 29, and an oil temperature sensor 30 are connected to the input port of the ECU 3.

The air-fuel ratio sensor 25 detects a wide range of continuous changes in the air-fuel ratio from the oxygen concentration of the exhaust gas of the engine 2.

The engine rotation speed sensor 26 outputs an engine rotation speed pulse signal having a pulse number proportional to the rotation speed of the crankshaft 9 from the rotation of the crankshaft 9 of the engine 2. The ECU 3 can detect the engine speed based on the engine speed pulse signal.

The accelerator opening sensor 28 detects an accelerator opening that represents the amount of operation of the accelerator pedal 27. The water temperature sensor 29 detects the temperature of the cooling water of the engine 2. The oil temperature sensor 30 detects the temperature of the engine oil, which is the lubricating oil of the engine 2.

On the other hand, various control objects such as a spark plug 10, an injector 11, and a throttle valve 15 are connected to the output port of the ECU 3.

The ECU 3 calculates the required load of the engine 2 based on the accelerator opening degree detected by the accelerator opening degree sensor 28, and calculates the target ignition timing, the fuel injection amount, and the intake air amount of the engine 2 according to the required load. Then, the ECU 3 controls the spark plug 10, the injector 11, and the throttle valve 15 so as to obtain the calculated target ignition timing, fuel injection amount, and intake air amount, and controls the operating state of the engine 2.

In this embodiment, the ECU 3 estimates the fuel dilution rate of the engine oil. The ECU 3 sets the fuel dilution rate to zero at the time of a new vehicle or after changing the engine oil, and increases the fuel dilution rate according to the operating state of the engine 2.

For example, in normal engine operation, the ECU 3 obtains the fuel dilution rate increase rate per unit time from a map in which the fuel dilution rate increase rate per unit time is determined by the engine speed and the engine load, and the dilution rate is determined every predetermined time. Accumulate the increase in.

The ECU 3 calculates and adds the fuel dilution rate from, for example, the total amount of post injection for maintaining the performance of the exhaust gas purification system.

The ECU 3 calculates, for example, the amount of fuel evaporation during engine operation, calculates the amount of decrease in the fuel dilution rate based on the amount of fuel evaporation, and subtracts it from the fuel dilution rate.

The ECU 3 stores the calculated fuel dilution rate in the flash memory when the ignition switch (not shown) is turned off, reads it out the next time the ignition switch is turned on, and increases the fuel dilution rate according to the operating state of the engine 2.

The fuel dilution stored when the ignition switch is turned off depends on the engine temperature when the ignition switch is turned off, for example, the cooling water temperature, and the time from the ignition switch off to the ignition switch on. May be corrected.

By doing so, the amount of fuel evaporation in the engine oil from the time when the ignition switch is turned off to the time when the ignition switch is turned on can be taken into consideration, and the fuel dilution rate can be estimated accurately.

In this embodiment, the ECU 3 estimates the iron concentration as the amount of metal contained in the engine oil, and determines the deterioration of the engine oil based on the estimated iron concentration.

The cause of the increase in metal in engine oil is the friction between the piston ring and the cylinder liner. The material of the piston ring and the cylinder liner is mainly iron, and when an oil film is not formed between the piston ring and the cylinder liner, such as when starting the engine 2, wear of these members is promoted.

The ECU 3 calculates, for example, the amount of increase in the base iron concentration based on the oil temperature, which is the temperature of the engine oil when the engine is started.

The ECU 3 may correct the increase in the base iron concentration by, for example, a factor that affects the iron concentration of the engine oil.

The ECU 3 corrects the amount of increase in the base iron concentration based on, for example, the fuel dilution rate of the engine oil. The ECU 3 calculates, for example, a correction coefficient or an additional concentration for the base iron concentration increase amount as an iron concentration increase correction value based on the fuel dilution rate of the engine oil, and multiplies the base iron concentration increase amount by the correction coefficient to make an increase correction. Calculate the amount, or add the additional concentration to the base iron concentration increase amount to calculate the increase correction amount.

The ECU 3 adds the calculated correction increase amount to the post-start iron concentration calculated at the time of the previous engine start, and stores it in the flash memory as the current post-start iron concentration.

When the iron concentration is equal to or higher than a predetermined value, the ECU 3 determines that the engine oil has deteriorated.

The iron concentration calculation process by the lubricating oil deterioration determination device according to the present embodiment configured as described above will be described with reference to FIG. The iron concentration calculation process described below is started when the ignition switch is turned on.

In step S1, the ECU 3 sets the iron concentration after the start stored last time as the iron concentration before the start this time, reads out the fuel dilution ratio stored when the ignition switch was turned off last time, and the oil temperature of the engine oil when the ignition switch is turned on. To read.

In step S2, the ECU 3 determines whether or not the start of the engine 2 is completed. Whether or not the start of the engine 2 is completed is determined, for example, by determining that the start is completed when the engine speed becomes higher than the predetermined speed. Further, it may be determined that the start is completed when the hydraulic switch attached to the engine 2 detects a predetermined normal oil pressure. If it is determined that the start of the engine 2 is not completed, the ECU 3 repeats the process of step S2.

When it is determined that the start of the engine 2 is completed, in step S3, the ECU 3 calculates the amount of increase in the base iron concentration from the oil temperature of the engine oil when the ignition switch is turned on.

In step S4, the ECU 3 calculates the iron concentration increase correction amount from the fuel dilution rate stored when the ignition switch was turned off last time.

In step S5, the ECU 3 calculates the increase correction amount from the base iron concentration increase amount and the iron concentration increase correction amount.

In step S6, the ECU 3 adds an increase correction amount to the iron concentration before starting this time, calculates the iron concentration after starting, and stores it in the flash memory.

In step S7, the ECU 3 determines whether or not the post-starting iron concentration obtained in step S6 is equal to or higher than a predetermined concentration. If it is determined that the iron concentration is equal to or higher than the predetermined concentration after the start, the ECU 3 determines the deterioration of the engine oil in step S8 and ends the process.
If it is determined that the iron concentration is not equal to or higher than the predetermined concentration after the start, the ECU 3 ends the process.

As described above, in this embodiment, the amount of increase in the base iron concentration is calculated based on the oil temperature of the engine oil.

When the engine 2 is started, the engine oil is not supplied or is low to the sliding members of the engine 2, so that the frictional resistance between the sliding members is large and metal wear is likely to occur. In addition, the viscosity of engine oil changes depending on the temperature. Since the amount of increase in the base iron concentration is calculated based on the oil temperature of the engine oil when the engine 2 is started, the deterioration of the engine oil can be accurately determined.

The higher the temperature of the engine oil, the easier it is for metals to be mixed in, and the greater the amount of increase in iron concentration. This is because the higher the oil temperature, the lower the viscosity of the engine oil, the thinner the oil film thickness between the piston ring and the cylinder liner, and the easier it is for these sliding members to come into contact with each other, resulting in a large increase in iron concentration. Become.

Further, since the amount of increase in iron concentration is calculated when the engine 2 is started because metal is relatively easily mixed in the engine oil, the calculation load by the lubricating oil deterioration determination device can be reduced.

Further, since the increase in the base iron concentration is corrected by the fuel dilution amount, the deterioration of the engine oil can be accurately determined.

When the lubrication performance of the engine oil is lowered by dilution with fuel, the viscosity of the engine oil is lowered and the oil film forming property of the sliding member of the engine 2 is lowered. Then, the amount of metal mixed in the engine oil increases more than in the case without fuel dilution. By correcting the amount of increase in the base iron concentration by the fuel dilution rate, the amount of increase in metal can be corrected, and the amount of metal in the engine oil can be accurately obtained.

In this implementation, the amount of increase in base iron concentration was calculated based on the oil temperature of the engine oil, but the amount of increase in base iron concentration may be calculated based on the temperature of the cooling water of the engine 2.

In another embodiment of the present embodiment, the iron concentration increase correction value is calculated based on the time S required for starting the engine 2, which is the time from when the ignition switch is turned on until the start of the engine 2 is completed. ..

The ECU 3 in FIG. 1 calculates, for example, a correction coefficient or an additional concentration for the base iron concentration increase amount as an iron concentration increase correction value based on the time TimeS required for starting the engine 2, and corrects the base iron concentration increase amount to the base iron concentration increase amount. Is multiplied to calculate the increase correction amount, or the addition concentration is added to the base iron concentration increase amount to calculate the increase correction amount.

The ECU 3 obtains the correction coefficient or the addition concentration from, for example, a table in which the correction coefficient or the addition concentration is determined from the time TimeS required to start the engine 2.

The iron concentration increase correction value is set so that the longer the time TimeS required to start the engine 2 is, the larger the iron concentration increase correction value is.

The iron concentration calculation process by the lubricating oil deterioration determination device according to another aspect of the present embodiment configured in this way will be described with reference to FIG. The iron concentration calculation process described below is started when the ignition switch is turned on.

In step S11, the ECU 3 sets the iron concentration after the start stored last time as the iron concentration before the start this time, and reads the oil temperature of the engine oil when the ignition switch is turned on.

In step S12, the ECU 3 determines whether or not the start of the engine 2 is completed. If it is determined that the start of the engine 2 is not completed, the ECU 3 repeats the process of step S12.

When it is determined that the start of the engine 2 is completed, in step S13, the ECU 3 calculates the amount of increase in the base iron concentration from the oil temperature of the engine oil when the ignition switch is turned on.

In step S14, the ECU 3 detects the time required to start the engine 2 and sets it as TimeS.

In step S15, the ECU 3 calculates the iron concentration increase correction value based on TimeS.

In step S16, the ECU 3 calculates the increase correction amount from the base iron concentration increase amount and the iron concentration increase correction amount.

In step S17, the ECU 3 adds an increase correction amount to the iron concentration before starting this time, calculates the iron concentration after starting, and stores it in the flash memory.

In step S18, the ECU 3 determines whether or not the post-starting iron concentration obtained in step S17 is equal to or higher than a predetermined concentration. If it is determined that the iron concentration is equal to or higher than the predetermined concentration after the start, the ECU 3 determines the deterioration of the engine oil in step S19 and ends the process.
If it is determined that the iron concentration is not equal to or higher than the predetermined concentration after the start, the ECU 3 ends the process.

As described above, in another aspect of the present embodiment, since the amount of increase in the base iron concentration is corrected by the time TimeS required for starting the engine 2, the deterioration of the engine oil can be accurately determined.

If the battery condition is not normal and the engine does not start smoothly, the sliding members will wear out due to the long-term severe lubrication condition, so this decrease is the amount of increase in the iron concentration of the engine oil. It can be reflected, and the deterioration of engine oil can be accurately determined.

In this embodiment, the amount of increase in iron concentration was corrected by the fuel dilution rate, and in another aspect of this embodiment, the amount of increase in iron concentration was corrected by the time required to start the engine 2, but these are used in combination. The amount of increase in iron concentration may be corrected.

By doing so, the amount of increase in iron concentration in the engine oil can be obtained with high accuracy.

Further, in this embodiment and other aspects of this embodiment, the concentration of iron in the engine oil is monitored as an index of deterioration of the engine oil, but depending on the material of each component constituting the engine 2, aluminum or the like is used. It may be a metal component whose concentration is expected to increase according to the mileage of the vehicle 1.

Further, in the present embodiment and other aspects of the present embodiment, the engine 2 is a gasoline engine, but it may be an engine of another type, for example, a diesel engine.

In this embodiment, an example in which the ECU 3 performs various determinations and calculations based on various sensor information has been described, but the present invention is not limited to this, and the vehicle 1 is provided with a communication unit capable of communicating with an external device such as an external server. Various judgments and calculations are performed by the external device based on the detection information of various sensors transmitted from the unit, the judgment results and calculation results are received by the communication unit, and various judgment results and calculation results are used. Control may be performed.

Although the embodiments of the present invention have been disclosed, it is clear that some skilled in the art can make changes without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the following claims.

1 Vehicle 2 Engine (internal combustion engine)
3 ECU (control unit)
5 Cylinder 6 Piston 26 Engine speed sensor 28 Accelerator opening sensor 29 Water temperature sensor 30 Oil temperature sensor

Claims (2)

At the time of starting the internal combustion engine, the amount of increase in the metal in the lubricating oil is obtained based on the oil temperature of the lubricating oil of the internal combustion engine at the time of starting the internal combustion engine, and the amount of metal in the lubricating oil is equal to or higher than a predetermined value. In some cases, a lubricating oil deterioration determination device including a control unit for determining that the lubricating oil has deteriorated. The control unit increases the amount of metal in the lubricating oil as the fuel dilution ratio of the lubricating oil when the ignition switch is turned on increases, or as the time required to start the internal combustion engine increases. The lubricating oil deterioration determination device according to claim 1 for correction.

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