JP2024047858A - Oil control valve diagnostic device - Google Patents

Abstract

[Problem] To accurately diagnose a fault in an oil control valve. [Solution] A diagnostic device for an oil control valve 8 that controls the oil pressure supplied to a variable displacement oil pump 4 includes a viscosity sensor 43 that detects the actual viscosity of the oil, and a diagnostic unit 100 that diagnoses the oil control valve based on the actual viscosity detected by the viscosity sensor. The diagnostic unit is configured to execute a first step of calculating a target discharge amount of the variable displacement oil pump, a second step of calculating an actual discharge amount of the variable displacement oil pump, a third step of correcting the target discharge amount and the actual discharge amount based on the actual viscosity detected by the viscosity sensor, and a fourth step of diagnosing the oil control valve based on the corrected target discharge amount and the corrected actual discharge amount. [Selected Figure] Figure 1

Description

This disclosure relates to a diagnostic device for an oil control valve.

Variable displacement oil pumps are increasingly being adopted in internal combustion engines to improve fuel efficiency. In a variable displacement oil pump, the pump displacement is changed by varying the amount of hydraulic pressure supplied to the pump. This supplied hydraulic pressure is controlled by an oil control valve, which changes the supplied hydraulic pressure according to an instruction signal received from a control unit.

JP 2021-110318 A

However, if the oil control valve fails, the amount of oil discharged from the variable displacement oil pump will deviate from the target value, so it is desirable to detect failure of the oil control valve as soon as possible.

One possible method for diagnosing such oil control valves is to compare the actual oil pressure of the oil discharged from the variable displacement oil pump with a target oil pressure.

However, by comparing the oil pressure alone, it is not possible to determine whether the discrepancy in oil pressure is due to a failure of the oil control valve or some other cause, and as a result, it is difficult to accurately diagnose a failure of the oil control valve.

Therefore, this disclosure was devised in consideration of the above circumstances, and its purpose is to provide an oil control valve diagnostic device that can accurately diagnose failures in the oil control valve.

According to one aspect of the present disclosure,
A diagnostic device for an oil control valve that controls hydraulic pressure supplied to a variable displacement oil pump,
A viscosity sensor that detects the actual viscosity of the oil;
a diagnosis unit for diagnosing the oil control valve based on an actual viscosity detected by the viscosity sensor;
Equipped with
The diagnostic unit includes:
A first step of calculating a target discharge amount of the variable displacement oil pump;
A second step of calculating an actual discharge amount of the variable displacement oil pump;
a third step of correcting the target discharge amount and the actual discharge amount based on the actual viscosity detected by the viscosity sensor;
a fourth step of diagnosing the oil control valve based on the corrected target discharge amount and the corrected actual discharge amount;
The present invention provides a diagnostic device for an oil control valve, comprising:

Preferably, the diagnostic device includes an oil temperature sensor for detecting an actual oil temperature,
In the first step, the diagnostic unit calculates a target discharge amount based on an actual oil temperature detected by the oil temperature sensor.

Preferably, the diagnostic device comprises:
an oil temperature sensor for detecting an actual oil temperature;
A hydraulic pressure sensor that detects the actual oil pressure;
Equipped with
In the second step, the diagnostic unit calculates an actual discharge amount based on an actual oil temperature detected by the oil temperature sensor and an actual oil pressure detected by the oil pressure sensor.

Preferably, in the fourth step, the diagnostic unit
When the difference obtained by subtracting the corrected actual discharge amount from the corrected target discharge amount is greater than a predetermined threshold value, it is determined that the oil control valve has a stuck-open fault.

Preferably, in the fourth step, the diagnostic unit
When the difference obtained by subtracting the corrected target discharge amount from the corrected actual discharge amount is greater than a predetermined threshold value, it is determined that the oil control valve has a stuck-closed fault.

This disclosure makes it possible to accurately diagnose oil control valve failures.

1 is a schematic diagram showing an oil supply device for an internal combustion engine according to an embodiment of the present invention; 3 is a flowchart showing a diagnostic method according to the present embodiment.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. Please note that the present disclosure is not limited to the following embodiments.

Figure 1 is a schematic diagram showing an oil supply device for an internal combustion engine according to an embodiment of the present disclosure. The internal combustion engine (engine) is a multi-cylinder diesel engine for a vehicle, and the vehicle is a large vehicle such as a truck. Note that the type of vehicle is not limited to this, and may be, for example, a small vehicle such as a passenger car. The engine may be applied to a moving body other than a vehicle, such as a ship, construction machinery, or industrial machinery, or may be a stationary engine.

The oil supply device 1 includes an oil pan 2 that stores lubricating oil O, and a variable displacement oil pump 4 (hereinafter also referred to simply as an oil pump) that draws oil O from the oil pan 2 and discharges it toward an oil gallery 3, which is the initial oil supply destination. An oil filter 5 that filters the oil O drawn from the oil pan 2 is provided on the inlet side of the oil pump 4. The oil gallery 3 is connected to the outlet of the oil pump 4 via a pump outlet passage 6. The oil gallery 3 is connected to various parts of the engine (bearings, etc.) to which oil is to be supplied.

The oil pump 4 is, for example, a pendulum oil pump, a vane oil pump, or an internal gear oil pump. The oil pump 4 is driven to rotate by the engine crankshaft. The oil pump 4 has a control chamber 7 therein, and changes the pump capacity according to the magnitude of the oil pressure supplied to the control chamber 7, i.e., the controlled oil pressure. In this embodiment, the larger the controlled oil pressure is, the smaller the pump capacity is, and the less oil is discharged per one revolution of the pump. Conversely, the smaller the controlled oil pressure is, the larger the pump capacity is, and the more oil is discharged per one revolution of the pump.

The oil supply device 1 is equipped with an oil control valve (hereinafter referred to as OCV) 8 that controls the control oil pressure supplied to the control chamber 7 of the oil pump 4. The OCV 8 is composed of a spool valve. The inlet of the OCV 8 is connected to the oil passage 6 on the oil pump outlet side via an OCV inlet passage 9. The outlet of the OCV 8 is connected to the control chamber 7 of the oil pump 4 via an OCV outlet passage 10. The OCV 8 is a normally closed type that is normally closed.

A control device is provided to control the oil supply device 1, particularly the OCV 8. The control device includes an electronic control unit (ECU (Electronic Control Unit)) 100 as a control unit, circuit element, or controller. The ECU 100 includes a CPU (Central Processing Unit) with calculation functions, storage media such as ROM (Read Only Memory) and RAM (Random Access Memory), input/output ports, and storage devices other than the ROM and RAM. The ECU 100 is configured to control not only the oil supply device 1 but the entire engine.

Furthermore, components of the control device include a crank angle sensor 40 for detecting the engine crank angle and rotation speed (specifically, revolutions per minute (rpm)), an oil temperature sensor 41 for detecting the actual oil temperature, an oil pressure sensor 42 for detecting the actual oil pressure, and a viscosity sensor 43 for detecting the actual oil viscosity. The output signals of these sensors are sent to the ECU 100. The oil temperature sensor 41, the oil pressure sensor 42, and the viscosity sensor 43 are provided in the oil passage 6.

As mentioned above, if the OCV 8 fails, the amount of oil discharged from the oil pump 4 will deviate from the target value, so it is desirable to detect a failure of the OCV 8 as soon as possible.

One possible method for diagnosing the OCV 8 is to compare the actual oil pressure of the oil discharged from the oil pump 4 with a target oil pressure.

However, by comparing oil pressure alone, it is not possible to determine whether the discrepancy in oil pressure is due to a malfunction of the OCV8 or to other causes, particularly deterioration in oil quality, and as a result, it is difficult to accurately diagnose a malfunction of the OCV8.

The diagnostic device of this embodiment is configured to solve this problem. The diagnostic device of this embodiment includes the viscosity sensor 43 and the ECU 100. The ECU 100 functions as a diagnostic unit as defined in the claims.

The ECU 100 is configured to execute the following first to fourth steps.
(1) A first step of calculating a target discharge amount Ma of the oil pump 4 (a discharge amount as a target value).
(2) A second step of calculating the actual discharge amount Mb of the oil pump 4.
(3) a third step of correcting the target discharge amount Ma and the actual discharge amount Mb based on the actual viscosity μo detected by the viscosity sensor 43;
(4) A fourth step of diagnosing the OCV 8 based on the corrected target discharge amount Mac and the corrected actual discharge amount Mbc.

The diagnostic device of this embodiment also includes the oil temperature sensor 41 and oil pressure sensor 42 mentioned above.

Next, the diagnosis method of this embodiment will be described with reference to FIG. 2. The routine shown in the figure is repeatedly executed by the ECU 100 at a predetermined calculation period τ (e.g., 10 msec).

First, in step S101, the ECU 100 determines whether the diagnosis permission flag is on. The diagnosis permission flag is a flag that is on when predetermined conditions suitable for diagnosis are met, and is off otherwise. If the diagnosis permission flag is on, diagnosis is permitted (S101: Yes) and the process proceeds to step S102. If the diagnosis permission flag is not on (off), diagnosis is prohibited (S101: No) and the current routine is ended.

In this embodiment, the condition for the diagnosis permission flag to be turned on is that all of the following conditions (1) to (4) are satisfied.
(1) The actual oil temperature To detected by the oil temperature sensor 41 is within a predetermined range suitable for diagnosis.
(2) The actual water temperature (the actual temperature of the engine coolant) Tw detected by a water temperature sensor (not shown) is within a predetermined range suitable for diagnosis.
(3) The engine speed Ne detected by the crank angle sensor 40 is within a predetermined range suitable for diagnosis.
(4) The OCV 8 is under feedback control.

Next, in step S102, the ECU 100 acquires the engine speed Ne value detected by the crank angle sensor 40, the actual oil temperature To value detected by the oil temperature sensor 41, the actual oil pressure Po value detected by the oil pressure sensor 42, the actual viscosity μo value detected by the viscosity sensor 43, and the command value sent from the ECU 100 to the OCV 8.

The command value sent from ECU 100 to OCV 8 is specifically the duty ratio D, and OCV 8 is controlled to an opening corresponding to the sent duty ratio D. The value of this duty ratio D is determined, for example, according to a predetermined map (which may be a table, function, etc.; the same applies below) based on the engine speed Ne and the target fuel injection amount Qt. The target fuel injection amount Qt is a target value of the fuel injection amount for the fuel injection injector (not shown). The value of the target fuel injection amount Qt is determined, for example, according to a predetermined map based on the engine speed Ne and the accelerator opening Ac.

Next, in step S103, the ECU 100 calculates or converts the rotation speed of the oil pump 4 (called the pump rotation speed) Np from the acquired value of the engine rotation speed Ne.

In steps S104 to S106, the target discharge amount Ma is calculated. In step S104, the ECU 100 calculates the first element Ma1, which is an element in the calculation of the target discharge amount Ma. At this time, the ECU 100 calculates the first element Ma1 according to a predetermined map based on the pump rotation speed Np and the actual oil temperature To.

In step S105, the ECU 100 calculates a second element Ma2, which is another element in the calculation of the target discharge amount Ma. At this time, the ECU 100 calculates the second element Ma2 based on the value of the duty ratio D and in accordance with a predetermined map.

In step S106, the ECU 100 calculates the target discharge amount Ma. At this time, the ECU 100 calculates the target discharge amount Ma by multiplying the first element Ma1 by the second element Ma2 (Ma = Ma1 x Ma2).

In steps S107 and S108, the target discharge amount Ma is corrected. In step S107, the ECU 100 calculates a correction amount for correcting the target discharge amount Ma, i.e., a target value correction amount Ka. At this time, the ECU 100 calculates the target value correction amount Ka based on the value of the actual viscosity μo and in accordance with a predetermined map.

In step S108, the ECU 100 calculates the corrected target discharge amount Ma, i.e., the corrected target discharge amount Mac. At this time, the ECU 100 calculates the corrected target discharge amount Mac by multiplying the target discharge amount Ma by the target value correction amount Ka (Mac = Ka x Ma). As can be seen from this, the target value correction amount Ka in this embodiment serves as a correction coefficient.

Next, in step S109, the actual discharge amount Mb is calculated. At this time, the ECU 100 calculates the actual discharge amount Mb according to a predetermined map based on the actual oil temperature To and the actual oil pressure Po.

In steps S110 and S111, the actual discharge amount Mb is corrected. In step S110, the ECU 100 calculates the correction amount for correcting the actual discharge amount Mb, i.e., the actual value correction amount Kb. At this time, the ECU 100 calculates the actual value correction amount Kb based on the value of the actual viscosity μo and in accordance with a predetermined map.

In this embodiment, the same map is used when calculating the actual value correction amount Kb and when calculating the target value correction amount Ka. Therefore, the value of the calculated actual value correction amount Kb is the same as the value of the calculated target value correction amount Ka (Ka = Kb). Therefore, in this step S110, the calculated value of the target value correction amount Ka may simply be replaced with the value of the actual value correction amount Kb.

Alternatively, different maps may be used when calculating the actual value correction amount Kb and when calculating the target value correction amount Ka, and different values of the target value correction amount Ka and the actual value correction amount Kb may be calculated.

In step S111, the ECU 100 calculates the corrected actual discharge amount Mb, i.e., the corrected actual discharge amount Mbc. At this time, the ECU 100 calculates the corrected actual discharge amount Mbc by multiplying the actual discharge amount Mb by the actual value correction amount Kb (Mbc = Kb x Mb). As can be seen from this, the actual value correction amount Kb in this embodiment serves as a correction coefficient.

In steps S112 to S117, OCV8 is diagnosed based on the corrected target discharge amount Mac and the corrected actual discharge amount Mbc.

In step S112, the ECU 100 subtracts the corrected actual discharge amount Mbc from the corrected target discharge amount Mac to calculate the discharge amount difference (discharge amount difference for open stuck diagnosis) ΔMab (ΔMab = Mac - Mbc).

In step S113, the ECU 100 determines whether the discharge amount difference ΔMab is greater than a predetermined threshold value (open stuck diagnosis threshold value) ΔMabs.

If it is determined that the difference is greater, the process proceeds to step S114, where the ECU 100 determines that the OCV 8 is experiencing a stuck open fault, and ends this routine.

A stuck open failure is a failure in which the actual opening of the OCV 8 is excessive relative to the target opening corresponding to the duty ratio D. For convenience, the term "stuck open failure" is used, but the cause may be a variety of other causes other than sticking of the spool valve body. When such a stuck open failure occurs, the control oil pressure supplied from the OCV 8 increases above the target value, so the actual discharge amount Mb discharged from the oil pump 4 is less than the target discharge amount Ma. This means that the amount of oil supplied to the engine may be insufficient, resulting in poor lubrication.

On the other hand, if it is determined in step S113 that the discharge amount difference ΔMab is not greater than the threshold value ΔMabs (is equal to or less than the threshold value ΔMabs), the ECU 100 proceeds to step S115 and calculates the discharge amount difference (discharge amount difference for closed stuck diagnosis) ΔMba by subtracting the corrected target discharge amount Mac from the corrected actual discharge amount Mbc (ΔMba = Mbc - Mac).

In step S116, the ECU 100 determines whether the discharge amount difference ΔMba is greater than a predetermined threshold value (closed stuck diagnosis threshold value) ΔMbas.

If it is determined that the difference is greater, the process proceeds to step S117, where the ECU 100 determines that the OCV 8 is stuck closed. The current routine then ends.

A stuck-closed failure is a failure in which the actual opening of the OCV 8 is too small relative to the target opening corresponding to the duty ratio D. For convenience, the term "stuck-closed failure" is used, but the cause may be a variety of other causes other than sticking of the spool valve body. When such a stuck-closed failure occurs, the control oil pressure supplied from the OCV 8 decreases below the target value, so the actual discharge amount Mb discharged from the oil pump 4 becomes excessive relative to the target discharge amount Ma. Therefore, the driving energy of the oil pump 4 is wasted, which may result in a deterioration of fuel efficiency.

On the other hand, if it is determined in step S116 that the discharge amount difference ΔMba is not greater than the threshold value ΔMbas (is equal to or less than the threshold value ΔMbas), the ECU 100 ends this routine. This is equivalent to determining that the OCV 8 is normal and not malfunctioning.

In the above control, the target discharge amount Ma and the actual discharge amount Mb are corrected based on the actual viscosity μo detected by the viscosity sensor 43 (steps S108, S111). Then, the OCV8 is diagnosed based on the corrected target discharge amount Mac and the corrected actual discharge amount Mbc (steps S112 to S117). This improves diagnostic accuracy and enables the OCV8 to be accurately diagnosed for malfunctions.

In general, the deviation between the target discharge amount and the actual discharge amount can occur not only due to OCV failure, but also due to other causes, typically deterioration in oil quality. Deterioration in oil quality includes oxidation, contamination (including an increase in foreign matter), shearing, and dilution of the oil. The deviation between the target discharge amount and the actual discharge amount can also occur due to the use of a different type of oil.

However, these other causes will manifest themselves in changes in oil viscosity. For example, the viscosity will increase when the oil oxidizes, and will also increase when the oil becomes dirty. The viscosity will decrease when the oil is sheared or diluted. When a different oil is used, the viscosity will increase or decrease depending on the type of different oil.

Therefore, according to this embodiment, by correcting the target discharge amount Ma and the actual discharge amount Mb based on the actual viscosity μo, the values of the corrected target discharge amount Mac and the corrected actual discharge amount Mbc can include deviations in each amount due to other causes. In other words, it is possible to calculate the corrected target discharge amount Mac and the corrected actual discharge amount Mbc that reflect the influence of other causes.

Therefore, by determining whether the fault is stuck open or stuck closed based on the values of the corrected target discharge amount Mac and the corrected actual discharge amount Mbc, specifically the difference between the two values ΔMab and ΔMba, diagnostic accuracy can be improved and a fault in the OCV8 can be accurately diagnosed.

In addition, in this embodiment, diagnosis is performed based on the oil volume rather than the oil pressure. Generally, bearing reliability is evaluated based on the Stribeck curve, and each specified value is often expressed in units of oil volume, so diagnosing based on the oil volume makes it possible to evaluate using the same standards, which is convenient.

Incidentally, in this embodiment, when the discharge amount difference ΔMab (=Mac-Mbc) is greater than the threshold value ΔMabs (ΔMab>ΔMabs), it is determined that an open stuck failure has occurred. This means that an open stuck failure is determined to have occurred when the corrected actual discharge amount Mbc is less than the corrected target discharge amount Mac. Therefore, "open stuck failure" includes "an abnormality in which the corrected actual discharge amount Mbc is less than the corrected target discharge amount Mac."

Similarly, in this embodiment, when the discharge amount difference ΔMba (=Mbc-Mac) is greater than the threshold value ΔMbas (ΔMba>ΔMbas), a closed sticking failure is determined to have occurred. This means that a closed sticking failure is determined to have occurred when the corrected actual discharge amount Mbc is greater than the corrected target discharge amount Mac. Therefore, a "closed sticking failure" includes an "abnormality in which the corrected actual discharge amount Mbc is greater than the corrected target discharge amount Mac."

According to this embodiment, it is therefore possible to perform a performance diagnosis to simply determine whether the actual discharge amount is greater or less than the target discharge amount, regardless of whether the OCV8 is malfunctioning or not.

Although the embodiments of the present disclosure have been described in detail above, various embodiments and variations of the present disclosure are possible.

(1) For example, if the discharge amount difference ΔMab is greater than the threshold value ΔMabs (ΔMab>ΔMabs) for a predetermined period of time, it may be determined that an open stuck fault has occurred. This can reduce erroneous diagnosis and improve diagnostic accuracy.

(2) Similarly, if the discharge amount difference ΔMba remains greater than the threshold value ΔMbas (ΔMba > ΔMbas) for a predetermined period of time, it may be determined that a stuck-closed fault has occurred.

(3) The application of this disclosure is not limited to oil supply devices for internal combustion engines and is arbitrary.

(4) Contrary to the above embodiment, the corrected actual discharge amount Mbc may be calculated first, and the corrected target discharge amount Mac may be calculated later.

The embodiments of the present disclosure are not limited to the above-mentioned embodiments, and all modifications, applications, and equivalents encompassed within the concept of the present disclosure as defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be interpreted in a limited manner, and may be applied to any other technology that falls within the scope of the concept of the present disclosure.

4 Variable capacity oil pump 8 Oil control valve (OCV)
41 Oil temperature sensor 42 Oil pressure sensor 43 Viscosity sensor 100 Electronic control unit (ECU)

According to one aspect of the present disclosure,
A diagnostic device for an oil control valve that controls hydraulic pressure supplied to a variable displacement oil pump,
A viscosity sensor that detects the actual viscosity of the oil;
a diagnosis unit for diagnosing the oil control valve based on an actual viscosity detected by the viscosity sensor;
Equipped with
The diagnostic unit includes:
A first step of calculating a target discharge amount of the variable displacement oil pump;
A second step of calculating an actual discharge amount of the variable displacement oil pump;
a third step of correcting the target discharge amount and the actual discharge amount based on the actual viscosity detected by the viscosity sensor;
a fourth step of diagnosing a failure of the oil control valve based on the corrected target discharge amount and the corrected actual discharge amount;
The present invention provides a diagnostic device for an oil control valve, comprising:

Claims (5)

A diagnostic device for an oil control valve that controls hydraulic pressure supplied to a variable displacement oil pump,
A viscosity sensor that detects the actual viscosity of the oil;
a diagnosis unit for diagnosing the oil control valve based on an actual viscosity detected by the viscosity sensor;
Equipped with
The diagnostic unit includes:
A first step of calculating a target discharge amount of the variable displacement oil pump;
A second step of calculating an actual discharge amount of the variable displacement oil pump;
a third step of correcting the target discharge amount and the actual discharge amount based on the actual viscosity detected by the viscosity sensor;
a fourth step of diagnosing the oil control valve based on the corrected target discharge amount and the corrected actual discharge amount;
A diagnostic device for an oil control valve, comprising: Equipped with an oil temperature sensor that detects the actual oil temperature,
2. The diagnostic device for an oil control valve according to claim 1, wherein the diagnostic unit calculates a target discharge amount based on an actual oil temperature detected by the oil temperature sensor in the first step. an oil temperature sensor for detecting an actual oil temperature;
A hydraulic pressure sensor that detects the actual oil pressure;
Equipped with
2. The diagnostic device for an oil control valve according to claim 1, wherein in the second step, the diagnostic unit calculates an actual discharge amount based on an actual oil temperature detected by the oil temperature sensor and an actual oil pressure detected by the oil pressure sensor. In the fourth step, the diagnostic unit
2. The diagnostic device for an oil control valve according to claim 1, wherein when a difference obtained by subtracting a corrected actual discharge amount from a corrected target discharge amount is greater than a predetermined threshold value, it is determined that the oil control valve has a stuck-open fault. In the fourth step, the diagnostic unit
2. The diagnostic device for an oil control valve according to claim 1, wherein when a difference obtained by subtracting the corrected target discharge amount from the corrected actual discharge amount is greater than a predetermined threshold value, it is determined that the oil control valve has a stuck-closed fault.

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