KR102300882B1 - Engine oil dilution diagn0stic appatatus and method - Google Patents

Abstract

Disclosed are an apparatus and method for diagnosing an engine oil dilution phenomenon. An engine oil dilution phenomenon diagnosis apparatus of the present invention includes an air-fuel ratio measuring unit for measuring an air-fuel ratio of an engine; a crankcase pressure detection unit for detecting the pressure of the crankcase of the engine; a turbocharger pressure detection unit for detecting a pressure of a turbocharger of the engine; and a diagnostic unit for diagnosing the engine oil dilution phenomenon based on the air-fuel ratio, the crankcase pressure, and the turbocharger pressure.

Description

Device and method for diagnosing engine oil dilution phenomenon

The present invention relates to an apparatus and method for diagnosing an engine oil dilution phenomenon, and more particularly, to a method for diagnosing an engine oil dilution phenomenon based on a change amount of an air-fuel ratio of an engine and a change amount of a blow-by gas. It relates to an engine oil dilution phenomenon diagnosis apparatus and method.

In general, in diesel vehicles using DPF, engine oil dilution occurs in which engine oil and diesel fuel are mixed.

The dilution of engine oil deteriorates the physical and chemical properties of automotive lubricants, may cause engine wear or engine failure, and increase the soot (LOS) in the lubricant, which causes frequent oil changes. In addition, when the engine oil dilution phenomenon continuously occurs, the amount of the diluted diesel fuel is excessively increased and introduced into the cylinder again through a blow-by gas line. In addition, the fuel introduced into the cylinder may be auto-ignited to increase the output of the engine or act as a factor causing the engine start to be turned off.

The background technology of the present invention is disclosed in 'A method for reducing the dilution rate of engine oil' of Korean Patent Application Laid-Open No. 10-2018-0124543 (November 21, 2018).

Conventionally, in order to prevent diesel fuel from flowing into an engine oil pan, various methods for injecting diesel fuel have been proposed. However, if the driver continuously repeats city driving, even if the fuel injection method is improved, the engine oil dilution caused by continuous DPF regeneration cannot be completely prevented.

If engine oil dilution occurs continuously, engine oil may flow into the cylinder through the blow-by gas line and cause fatal engine defects such as engine shutdown or unintentional increase in output. For this reason, if the increase in engine oil due to engine oil dilution exceeds a certain amount, the driver must be notified and the engine oil change must be induced.

However, in the case of a general engine oil pressure sensor, since it is used for the purpose of detecting the depletion of engine oil, a warning light is displayed on the cluster only when the pressure of the engine oil pan is lowered below the standard value. If the engine oil dilution occurs, the engine oil pan pressure does not drop below the engine oil warning lamp lighting threshold, so the driver cannot recognize the dangerous situation. This means that, in the case of a general vehicle, it is impossible to induce normal vehicle management by making the driver aware that engine oil dilution occurs.

The present invention has been devised to improve the above problems, and an object according to an aspect of the present invention is to diagnose and warn of engine oil dilution phenomenon based on the change amount of the air-fuel ratio of the engine and the change amount of the blow-by gas. To provide an apparatus and method.

An apparatus for diagnosing an engine oil dilution phenomenon according to an aspect of the present invention includes: an air-fuel ratio measuring unit for measuring an air-fuel ratio of an engine; a crankcase pressure detection unit for detecting the pressure of the crankcase of the engine; a turbocharger pressure detection unit for detecting a pressure of a turbocharger of the engine; and a diagnostic unit configured to diagnose an engine oil dilution phenomenon based on the air-fuel ratio, the crankcase pressure, and the turbocharger pressure.

The diagnostic unit of the present invention may include calculating an engine oil dilution phenomenon diagnostic coefficient using the air-fuel ratio, the crankcase pressure, and the turbocharger pressure.

The diagnostic coefficient of the engine oil dilution phenomenon of the present invention is characterized in that it enables constant diagnosis in the entire driving range of the engine.

The diagnosis unit of the present invention may calculate the engine oil dilution phenomenon diagnosis coefficient based on an air-fuel ratio change amount of the air-fuel ratio and a pressure difference change amount between the pressure of the crankcase and the pressure of the turbocharger.

The amount of change in the air-fuel ratio of the present invention is characterized in that it is the amount of change between the initial air-fuel ratio in a state in which the engine oil dilution phenomenon mapped during engine manufacturing does not occur and the air-fuel ratio measured through the sensor after the engine oil dilution phenomenon occurs.

The engine oil dilution phenomenon diagnostic coefficient of the present invention is the square root of the currently detected pressure difference between the pressure of the crankcase and the pressure of the turbocharger. It is characterized in that it is calculated based on a value divided by the square root.

The diagnosis unit of the present invention is characterized in that it diagnoses the engine oil dilution phenomenon based on whether the engine oil dilution diagnostic coefficient is within a preset range.

The present invention further comprises an output unit for warning the occurrence of the engine oil dilution phenomenon according to the diagnosis result of the diagnosis unit.

A method for diagnosing an engine oil dilution phenomenon according to an aspect of the present invention includes the steps of measuring an air-fuel ratio and calculating an air-fuel ratio change amount based on the measured air-fuel ratio; calculating a pressure difference change amount between the crankcase pressure and the turbocharger pressure by detecting the crankcase pressure and the turbocharger pressure, respectively; calculating an engine oil dilution phenomenon diagnosis coefficient based on the change amount of the air-fuel ratio and the pressure difference change amount, and diagnosing the engine oil dilution phenomenon based on the engine oil dilution phenomenon diagnosis coefficient; and outputting a diagnosis result of the engine oil dilution phenomenon.

The diagnostic coefficient of the engine oil dilution phenomenon of the present invention is characterized in that it enables constant diagnosis in the entire driving range of the engine.

The amount of change in the air-fuel ratio of the present invention is characterized in that it is the amount of change between the initial air-fuel ratio in a state in which the engine oil dilution phenomenon mapped during engine manufacturing does not occur and the air-fuel ratio measured through the sensor after the engine oil dilution phenomenon occurs.

The engine oil dilution phenomenon diagnostic coefficient of the present invention is the square root of the currently detected pressure difference between the pressure of the crankcase and the pressure of the turbocharger. It is characterized in that it is calculated based on a value divided by the square root.

The diagnosing the engine oil dilution phenomenon of the present invention is characterized in that the engine oil dilution phenomenon is diagnosed based on whether the engine oil dilution diagnostic coefficient is within a preset range.

In the step of outputting the diagnosis result of the present invention, when the engine oil dilution diagnostic coefficient is within the set range, it is characterized in that the occurrence of the engine oil dilution phenomenon is warned.

An apparatus and method for diagnosing engine oil dilution phenomenon according to an aspect of the present invention minimizes problems such as engine off or output increase by diagnosing and warning the engine oil dilution phenomenon based on the amount of change in engine oil pressure and air-fuel ratio.

An apparatus and method for diagnosing engine oil dilution phenomenon according to another aspect of the present invention warns a driver of engine oil dilution to induce engine oil change and ensure stable operation of a vehicle.

The engine oil dilution phenomenon diagnosis apparatus and method according to another aspect of the present invention diagnoses the engine oil dilution phenomenon based on the engine oil dilution phenomenon diagnosis coefficient, thereby determining whether the phenomenon in which the oil pressure is lowered is caused by engine oil depletion. It can be determined whether it is caused by

1 is a block diagram of an engine oil dilution phenomenon diagnosis apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing a test result of a change in engine control factor according to a change in blow-by gas concentration; FIG.
3 is a view showing the analysis of test results through the engine oil dilution phenomenon diagnostic coefficient according to an embodiment of the present invention.
4 is a flowchart of a method for diagnosing an engine oil dilution phenomenon according to an embodiment of the present invention.

Hereinafter, an apparatus and method for diagnosing an engine oil dilution phenomenon according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to intentions or customs of users and operators. Therefore, definitions of these terms should be made based on the content throughout this specification.

1 is a block diagram of an engine oil dilution phenomenon diagnosis apparatus according to an embodiment of the present invention, FIG. 2 is a view showing engine control factor change test results according to blow-by gas concentration change, and FIG. 3 is a diagram of the present invention It is a view showing the analysis of the test result through the engine oil dilution phenomenon diagnostic coefficient according to an embodiment.

1 is an apparatus for diagnosing engine oil dilution phenomenon according to an embodiment of the present invention; 50).

The air-fuel ratio measuring unit 10 measures the air-fuel ratio of the engine. Methods of measuring the air-fuel ratio of the engine may include a measuring method using a laser, a method using exhaust gas, and the like. The method of measuring an air-fuel ratio is not specifically limited.

The air-fuel ratio measuring unit 10 may measure the air-fuel ratio of the engine whenever a preset period arrives or when a preset vehicle driving condition is satisfied.

The crankcase pressure detection unit 20 detects the pressure of the crankcase. The crankcase pressure detection unit 20 detects the pressure of blow by gas flowing in the crankcase. As the crankcase pressure detection unit 20 , a pressure sensor installed on a flow path through which the blow-by gas flows may be employed.

In general, in an engine of a vehicle, an intake manifold uniformly supplies a mixture to a combustion chamber, and guides the mixture to flow into each combustion chamber through an intake runner. Here, the blow-by gas is an unburned exhaust gas that escapes from the combustion chamber to the crankcase through the gap between the cylinder and the piston during the compression and expansion strokes among the mixers supplied to the combustion chamber through the intake runner. The blow-by gas is 70-95% of unburned fuel (HC), and the remainder is composed of combustion gas, partially oxidized mixed gas, trace amounts of engine oil, soot, and moisture.

The turbocharger pressure detection unit 30 detects the pressure of the blow-by gas in the turbocharger for pressurizing intake air by using the pressure of the exhaust gas.

The diagnosis unit 40 diagnoses the engine oil dilution phenomenon based on the air-fuel ratio, the crankcase pressure, and the turbocharger pressure.

First, the diagnosis unit 40 calculates an air-fuel ratio change amount based on the air-fuel ratio measured by the air-fuel ratio measurement unit 10 . The amount of change in the air-fuel ratio is the amount of change between the initial air-fuel ratio mapped during engine manufacturing and the current air-fuel ratio.

Also, the diagnosis unit 40 detects a change amount of a pressure difference between the crankcase pressure and the turbocharger pressure respectively detected by the crankcase pressure detection unit 20 and the turbocharger pressure detection unit 30 . That is, the diagnostic unit 40 calculates the pressure difference between the pressure of the crankcase and the pressure of the turbocharger in the initial steady state, and thereafter, the pressure of the crankcase and the turbocharger at the current measurement time, for example, when the engine oil dilution phenomenon occurs. Calculate the pressure difference between the pressures of Next, the diagnosis unit 40 sets the initial pressure difference in the normal phase (the pressure difference between the crankcase pressure and the turbocharger pressure) and the pressure difference at the current measurement time (the pressure difference between the crankcase pressure and the turbocharger pressure). compare to calculate the pressure difference change amount.

For reference, in the present embodiment, the current measurement time is described as the time when the engine oil dilution phenomenon occurs for convenience of explanation.

Then, the diagnosis unit 40 calculates the engine oil dilution phenomenon diagnosis coefficient by using the air-fuel ratio change amount and the pressure difference change amount. Hereinafter, the process of calculating the engine oil dilution phenomenon diagnostic coefficient will be described in detail.

In general, as the dilution oil flowing into the crankcase increases, the viscosity of the engine oil decreases and the total oil amount increases, so the blow-by gas amount increases. In addition, the viscosity of the engine oil is lowered and the pressure of the crankcase is also lowered.

For example, if the amount of blow-by gas is as shown in Table 1, more than about 2.5 L of diesel fuel flows into 5.9 L of engine oil and the concentration of diluted oil is greater than about 30%, the blow-by gas begins to be collected in the oil catch tank. , it can be seen that when the concentration of the diluted oil is increased to 50%, the blow-by gas increases to 35 mL.

test conditions Test results fuel concentration Volume of
engine oil Volume of fuel(diesel) Weight of evap. gas Volume of
evap. gas 0%% 5.90L 0.00L 0g 0mL 10% 5.90L 0.66L 0g 0mL 20% 5.90L 1.48L 0g 0mL 30% 5.90L 2.53L 3g 10mL 40% 5.90L 3.93L 9.5g 20mL 50% 5.90L 5.90L 16.2g 35mL

Referring to this, it can be seen that when the concentration of the diluted oil increases by 30% or more, the diluted oil may flow into the cylinder excessively, and it can be seen that the engine oil dilution phenomenon can be diagnosed based on the concentration of the diluted oil. have.

In general, in order to diagnose the engine oil dilution phenomenon, the engine control factor that changes according to the increase in the concentration of the blow-by gas flowing into the cylinder is measured by each sensor as shown in FIG. 3 .

FIG. 2 shows the results of testing while increasing the concentration of the diluted oil in various engine operating regions.

Referring to FIG. 2 , it can be seen that the engine oil is diluted with diesel fuel to lower the concentration of the engine oil, thereby lowering the pressure of the engine oil pan. In addition, it can be seen that the density of the blow-by gas is increased by the diesel fuel dilution, so that the rotational force applied to the turbocharger compressor is increased, and at the same time, the turbocharger pressure is increased.

According to this phenomenon, as the engine oil pan pressure decreases and the turbocharger pressure increases, it can be predicted that the pressure difference between both ends decreases and the blow-by gas flow rate decreases.

Due to this, it can be seen that when the concentration of the diluted oil is 10% to 20%, the blow-by gas flow rate decreases despite the increase in the blow-by gas concentration, so that the air-fuel ratio signal Lambda, λ) is thinner compared to the normal state. have.

On the other hand, when the concentration of the diluted oil is increased by 30% or more, it can be seen that the air-fuel ratio signal is measured to be rich even though the blow-by gas flow rate is decreased. This is a phenomenon caused by excessively high blow-by gas concentration, and it can be confirmed through exhaust gas analysis that unburned hydrocarbon (HC) and carbon monoxide (CO) emissions significantly increase due to abnormal combustion caused by excessive blow-by gas inflow. have.

Based on these characteristics, it is possible to derive an engine oil dilution phenomenon diagnostic coefficient capable of detecting the oil dilution phenomenon.

The diagnosis unit 40 calculates an engine oil dilution phenomenon diagnosis coefficient.

First, the diagnosis unit 40 uses Equations 1 and 2 below to calculate the blow-by gas flow rate from Bernoulli's equation in order to calculate the engine oil dilution phenomenon diagnostic coefficient.

In Equations 1 and 2, P ₁ is the crankcase pressure, h ₁ is the crankcase height, and u ₁ is the crankcase flow velocity. P ₂ is the pressure of the turbocharger, h ₂ is the pressure of the turbocharger, and u ₂ is the flow rate of the turbocharger. A ₂ is the cross-sectional area of the crankcase, ρ is the density of the diluted oil, g is the acceleration due to gravity, and Q is the flow rate of the diluted oil.

Since the blow-by gas generated in the crankcase flows into the turbocharger ^{, assuming that the flow speed of the engine oil pan is 0 m/s 2} , the blow-by gas flow rate of the turbocharger stage can be calculated as shown in Equation (2).

In the blow-by gas flow rate equation of Equation 2, ρ, g, h ₁ , and h ₂ are fixed values that do not change depending on the diluted oil concentration, so the flow rate of the blow-by gas is the engine oil pan pressure (P ₁ ) and the turbocharger. It is determined by the pressure difference of the pressure (P _{2 ).} Based on this, the engine oil dilution phenomenon diagnosis coefficient (C _dilution ) can be expressed as in Equation 3 below.

In Equation 3, λ _i is the air-fuel ratio in the initial steady state, and λ _f is the air-fuel ratio after the occurrence of the oil dilution phenomenon. ΔP _i is the pressure difference between the crankcase pressure in the initial steady state and the turbocharger pressure, and ΔP _f is the pressure difference between the crankcase pressure and the turbocharger pressure after oil dilution occurs.

_{Referring to Equation 3, the oil dilution phenomenon diagnostic coefficient is that the square root of the pressure difference (ΔP f} ) between the crankcase pressure and the turbocharger pressure after the oil dilution phenomenon occurs is proportional to the blow-by gas flow rate, and the crankcase in the initial steady state It can be expressed by dividing by the square root of _{the pressure difference (ΔP i} ) between the pressure and the turbocharger pressure.

In addition, the factor for the change in the air-fuel ratio is when the difference between the engine oil dilution phenomenon and the initial steady-state air-fuel ratio (λi -λf ) is positive, the air-fuel ratio signal is expressed in a rich state, and when it is negative, it means that the air-fuel ratio signal is in a rich state.

Therefore, if the air-fuel ratio change shows a positive value even though the blow-by gas flow rate is reduced because the diluted oil concentration is 30% or more, the oil dilution phenomenon diagnostic coefficient displays a positive value, and when the diluted oil concentration is less than 30%, the oil dilution phenomenon is diagnosed The coefficient outputs a negative value.

Referring to FIG. 3 , the test analysis result through the engine oil dilution diagnostic coefficient is graphed. The y-axis is the diagnostic coefficient for engine oil dilution, and the x-axis is the change in the air-fuel ratio compared to the initial steady state. When the diagnostic coefficient is applied to the test result, a graph as shown in FIG. 3 can be derived.

In FIG. 3 , the third quadrant indicates a state in which the air-fuel ratio signal is thinly output due to a decrease in the blow-by gas flow rate, which can be interpreted as a decrease in the fuel component introduced as the engine oil dilution diagnostic coefficient decreases.

The first quadrant is a state in which a signal rich in an air-fuel ratio signal is output despite a decrease in the blow-by gas flow rate. It can be interpreted that the fuel concentration of the blow-by gas flowing into the cylinder is rich even though the flow rate of the blow-by gas is decreased as the result value of the first quadrant is farther from the origin. This is a phenomenon caused by engine oil dilution, and when the diagnostic coefficient exceeds a certain value, it may be determined that excessively rich blow-by gas flows into the cylinder.

In the present embodiment, when diagnosing the engine oil dilution phenomenon through the engine oil dilution diagnostic coefficient, the diagnosis can be performed over the entire operating region rather than a specific operating region of the engine, and the oil dilution phenomenon can be monitored at all times.

Furthermore, the diagnosis unit 40 diagnoses the engine oil dilution phenomenon according to the sign or size of the engine oil dilution diagnostic coefficient calculated as described above. That is, the diagnosis unit 40 can diagnose a phenomenon in which the dilution oil is excessively introduced into the cylinder according to the engine oil dilution phenomenon based on whether the engine oil dilution diagnostic coefficient is included within a preset range.

For example, if the engine oil dilution diagnostic coefficient is a positive number of 0.01 or more within the first quadrant as a result of the test analysis through the set range, for example, the engine oil dilution diagnostic coefficient, the engine oil dilution phenomenon occurs and the diluted oil enters the cylinder. It can be diagnosed as excessive influx.

Also, when the engine oil dilution diagnostic coefficient is positive, the diagnosis unit 40 may determine that a significant engine oil dilution has occurred.

The output unit 50 outputs the diagnosis result of the diagnosis unit 40 . That is, the output unit 50 warns the driver of the occurrence of the engine oil dilution phenomenon when the engine oil dilution diagnostic coefficient is within the set range as a result of the diagnosis of the diagnosis unit 40 . In this case, the output unit 50 may warn the engine oil change. A vehicle cluster may be employed as the output unit 50 , but is not limited thereto.

Hereinafter, a method for diagnosing an engine oil dilution phenomenon according to an embodiment of the present invention will be described in detail with reference to FIG. 4 .

4 is a flowchart of a method for diagnosing an engine oil dilution phenomenon according to an embodiment of the present invention.

Referring to FIG. 4 , the air-fuel ratio measurement unit 10 measures the air-fuel ratio of the engine (S10), the crankcase pressure detection unit 20 detects the blow-by-cas pressure in the crankcase (S20), and the turbocharger pressure detection unit In step 30, the pressure of the blow-by gas in the turbocharger for pressurizing intake air is detected by using the pressure of the exhaust gas (S30).

As described above, the air-fuel ratio of the engine is measured, and as the crankcase pressure and the turbocharger pressure are respectively detected, the diagnosis unit 40 calculates a diagnostic coefficient based on the change amount of the air-fuel ratio of the engine and the change amount of the blow-by gas. (S40).

First, the diagnosis unit 40 calculates the amount of change in the air-fuel ratio based on the air-fuel ratio measured by the air-fuel ratio measurement unit 10 , and detects the amount of change in the pressure of the crankcase and the pressure of the turbocharger. That is, the diagnostic unit 40 calculates the pressure difference between the pressure of the crankcase and the pressure of the turbocharger in the initial steady state, and thereafter, the pressure of the crankcase and the turbocharger at the current measurement time, for example, when the engine oil dilution phenomenon occurs. After calculating the pressure difference of the pressure of pressure difference) to calculate the pressure difference change amount.

Next, the diagnosis unit 40 calculates an engine oil dilution phenomenon diagnosis coefficient based on Equation 3 by using the air-fuel ratio change amount and the pressure difference change amount.

As the engine oil dilution phenomenon diagnosis coefficient is calculated, the diagnosis unit 40 determines whether the engine oil dilution diagnosis coefficient is within a set range ( S50 ).

As a result of the determination in step S50, if the engine oil dilution diagnostic coefficient is greater than or equal to the set range, 0.01, the engine oil dilution phenomenon occurs and the dilution oil is excessively introduced into the cylinder, and the driver is warned of the occurrence of the engine oil dilution phenomenon. (S60). In this case, the output unit 50 may warn the engine oil change.

As such, the engine oil dilution phenomenon diagnosis apparatus and method according to an embodiment of the present invention diagnose and warn the engine oil dilution phenomenon based on the change amount of engine oil pressure and the air-fuel ratio, thereby minimizing problems such as engine off or output increase. .

In addition, the apparatus and method for diagnosing engine oil dilution phenomenon according to an embodiment of the present invention warns the driver of engine oil dilution to induce engine oil change and ensure stable operation of the vehicle.

In addition, the engine oil dilution phenomenon diagnosis apparatus and method according to an embodiment of the present invention diagnoses the engine oil dilution phenomenon based on the engine oil dilution phenomenon diagnosis coefficient to determine whether the phenomenon in which the oil pressure is lowered is caused by engine oil depletion. It can be distinguished whether it is caused by oil dilution.

Implementations described herein may be implemented in, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Although discussed only in the context of a single form of implementation (eg, only as a method), implementations of the discussed features may also be implemented in other forms (eg, in an apparatus or a program). The apparatus may be implemented in suitable hardware, software and firmware, and the like. A method may be implemented in an apparatus such as, for example, a processor, which generally refers to a computer, a microprocessor, a processing device, including an integrated circuit or programmable logic device, or the like. Processors also include communication devices such as computers, cell phones, portable/personal digital assistants (“PDAs”) and other devices that facilitate communication of information between end-users.

Although the present invention has been described with reference to the embodiment shown in the drawings, this is merely exemplary, and it is understood that various modifications and equivalent other embodiments are possible by those skilled in the art. will understand Accordingly, the true technical protection scope of the present invention should be defined by the following claims.

10: air-fuel ratio measurement unit 20: crankcase pressure detection unit
30: turbocharger pressure detection unit 40: diagnostic unit
50: output unit

Claims (14)

an air-fuel ratio measuring unit for measuring the air-fuel ratio of the engine;
a crankcase pressure detection unit for detecting the pressure of the crankcase of the engine;
a turbocharger pressure detection unit for detecting a pressure of a turbocharger of the engine; and
and a diagnostic unit for diagnosing an engine oil dilution phenomenon based on the air-fuel ratio, the pressure of the crankcase, and the pressure of the turbocharger,
The diagnosis unit includes calculating an engine oil dilution phenomenon diagnosis coefficient by using the air-fuel ratio, the crankcase pressure, and the turbocharger pressure,
and the diagnosis unit calculates the engine oil dilution phenomenon diagnosis coefficient based on an air-fuel ratio change amount of the air-fuel ratio and a pressure difference change amount between the pressure of the crankcase and the pressure of the turbocharger. delete According to claim 1, wherein the engine oil dilution phenomenon diagnostic coefficient is
An engine oil dilution phenomenon diagnosis device, characterized in that it enables constant diagnosis in the entire driving range of the engine. delete The method according to claim 1, wherein the amount of change in the air-fuel ratio is
Engine oil dilution phenomenon diagnosis device, characterized in that it is the amount of change between the initial air-fuel ratio in a state in which the engine oil dilution phenomenon does not occur mapped during engine manufacturing and the air-fuel ratio measured through a sensor after the engine oil dilution phenomenon occurs. According to claim 1, wherein the engine oil dilution phenomenon diagnostic coefficient is
It is calculated based on a value obtained by dividing the square root of the pressure difference between the currently detected crankcase pressure and the turbocharger pressure by the square root of the pressure difference between the crankcase pressure and the turbocharger pressure in the initial state. A diagnostic device for engine oil dilution. According to claim 1, wherein the diagnostic unit
The engine oil dilution phenomenon diagnosis apparatus, characterized in that the diagnosis of the engine oil dilution phenomenon is diagnosed based on whether the engine oil dilution phenomenon diagnosis coefficient is within a preset range. The engine oil dilution phenomenon diagnosis apparatus according to claim 1, further comprising an output unit warning the occurrence of the engine oil dilution phenomenon according to the diagnosis result of the diagnosis unit. measuring the air-fuel ratio and calculating an air-fuel ratio change amount based on the measured air-fuel ratio;
calculating a pressure difference change amount between the crankcase pressure and the turbocharger pressure by detecting the crankcase pressure and the turbocharger pressure, respectively;
calculating an engine oil dilution phenomenon diagnosis coefficient based on the change amount of the air-fuel ratio and the pressure difference change amount, and diagnosing the engine oil dilution phenomenon based on the engine oil dilution phenomenon diagnosis coefficient; and
and outputting a diagnosis result of the engine oil dilution phenomenon. 10. The method of claim 9, wherein the engine oil dilution phenomenon diagnostic coefficient is
A method for diagnosing engine oil dilution phenomenon, characterized in that it enables constant diagnosis in the entire driving range of the engine. The method of claim 9, wherein the amount of change in the air-fuel ratio is
A method for diagnosing engine oil dilution, characterized in that it is the amount of change between the initial air-fuel ratio in a state in which the engine oil dilution phenomenon does not occur mapped during engine manufacturing and the air-fuel ratio measured through a sensor after the engine oil dilution phenomenon occurs. 10. The method of claim 9, wherein the engine oil dilution phenomenon diagnostic coefficient is
It is calculated based on a value obtained by dividing the square root of the pressure difference between the currently detected crankcase pressure and the turbocharger pressure by the square root of the pressure difference between the crankcase pressure and the turbocharger pressure in the initial state. How to diagnose engine oil dilution. The method of claim 9, wherein the diagnosing the engine oil dilution phenomenon comprises:
The engine oil dilution phenomenon diagnosis method, characterized in that the diagnosis of the engine oil dilution phenomenon is diagnosed based on whether the engine oil dilution phenomenon diagnosis coefficient is included within a preset range. The method of claim 13, wherein outputting the diagnosis result comprises:
The engine oil dilution phenomenon diagnosis method, characterized in that when the engine oil dilution phenomenon diagnostic coefficient is within the set range, warning the occurrence of the engine oil dilution phenomenon.

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