JP7269970B2 - Oil temperature sensor diagnostic device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an oil temperature sensor diagnosis device that performs characteristic diagnosis of an oil temperature sensor that detects the oil temperature of lubricating oil of an engine.

An engine mounted on a vehicle such as an automobile is provided with various temperature sensors such as a water temperature sensor for detecting the temperature of cooling water and an oil temperature sensor for detecting the temperature of lubricating oil (engine oil).
In order to ensure the accuracy and validity of various controls based on the detected values of such temperature sensors, it is necessary to perform on-board diagnostics as needed during use of the vehicle to check whether there are any abnormalities in the detection characteristics.

As a conventional technology related to the diagnosis of a temperature sensor mounted on a vehicle engine, for example, Patent Document 1 discloses a diagnostic device for a water temperature sensor that generates an output corresponding to the temperature of a coolant when a predetermined time has elapsed after the engine is started. It is described that a timing or a timing at which a predetermined amount of heat generated by the engine is generated is set as a measurement time, and a failure is determined when the amount of change in the sensor output from engine start to this measurement time is less than a predetermined value.

JP-A-2000-130242

Similarly to the water temperature sensor described above, the oil temperature sensor that detects the oil temperature of the engine oil is basically the same as the water temperature sensor described above, and the amount of change in the oil temperature sensor output (the amount of increase in the detected oil temperature) and the elapsed time after the engine is started. characteristics can be diagnosed by comparing
On the other hand, in a vehicle engine, in order to suppress fuel consumption, the engine is stopped when a predetermined idle stop condition is satisfied, and then automatically restarted when a predetermined restart condition is satisfied. idle stop control is performed.
In the past, idling stop control was often started after the engine warmed up (after the cooling water temperature reached a sufficiently high temperature), but in recent years engines have been designed to further reduce fuel consumption. , there is a tendency to expand the operating range in which idling stop control can be performed to a range in which the cooling water temperature is lower (for example, about 40°C).
As a result, the idle stop control may be performed to stop the engine while the elapsed time after engine start is being added in order to diagnose the characteristics of the oil temperature sensor.

If the engine is stopped by idling stop control while the lubricating oil temperature is rising, heat generation in the engine due to combustion ceases during that time, so the lubricating oil temperature rises stagnantly, resulting in the characteristic diagnosis of the oil temperature sensor. It is feared that there will be a hindrance to
In view of the problems described above, an object of the present invention is to provide an oil temperature sensor diagnosis device that can perform an appropriate diagnosis even when the engine is stopped by idle stop control during diagnosis of the oil temperature sensor. be.

The present invention solves the problems described above by means of the following solutions.
The invention according to claim 1 comprises an engine, an oil temperature sensor for detecting the oil temperature of the lubricating oil of the engine, and when a predetermined idle stop condition is satisfied, the engine is stopped and a predetermined restart condition is satisfied. and an idle stop control unit that performs idle stop control for automatically restarting the engine when the engine is cooled. a diagnostic value setting unit for setting a diagnostic value for diagnosing an abnormality in the oil temperature sensor, which is a value that is added in correlation with the elapsed operating time after starting the engine, and an oil temperature detected by the oil temperature sensor; is less than a predetermined determination value and the diagnostic value is equal to or greater than a predetermined value, the oil temperature sensor is determined to be abnormal, and the oil temperature detected by the oil temperature sensor is equal to or greater than the determination value and an abnormality determination unit configured to determine that the oil temperature sensor is normal, wherein the idle stop control unit determines whether the abnormality or normality is determined by the abnormality determination unit after the cold start of the engine. The idling stop control is performed when the predetermined idling stop condition is satisfied, and the diagnostic value setting section performs the idling stop control before the determination of the abnormality or the normality by the abnormality determination section is established. In the oil temperature sensor diagnosing device, the addition of the diagnostic value is stopped and a subtraction amount that increases according to the stop time of the engine by the idle stop control is subtracted from the diagnostic value when the idling stop control is detected. .
According to this, by stopping the addition of the diagnostic value while the engine is stopped when there is no heat generated by combustion in the engine, the oil temperature behavior when the engine is stopped by the idle stop control is appropriately reflected in the diagnostic value, and the oil temperature sensor can improve the diagnostic accuracy of

In addition, when the engine is stopped, the lubricating oil is cooled by heat radiation from the oil pan or the like to the outside air, which can be reflected in the diagnostic value. be able to.

In the invention according to claim 2, the oil temperature sensor diagnostic device includes an outside air temperature detection unit that detects a parameter correlated with the outside air temperature of the vehicle, and the diagnostic value setting unit detects 2. The oil temperature sensor diagnosis device according to claim 1, wherein the subtraction amount is increased.
According to this, by changing the amount of subtraction according to the outside air temperature, it is possible to more appropriately reflect the decrease in oil temperature in the diagnostic value while the engine is stopped, thereby further improving the diagnostic accuracy of the oil temperature sensor. can be done.

As described above, according to the present invention, it is possible to provide an oil temperature sensor diagnosis device capable of performing appropriate diagnosis even when the engine is stopped by idle stop control during diagnosis of the oil temperature sensor. can.

1 is a diagram schematically showing the configuration of an engine having an embodiment of an oil temperature sensor diagnostic device to which the present invention is applied; FIG. 2 is a block diagram schematically showing the configuration of a lubricating device for the engine of FIG. 1; FIG. 4 is a flow chart showing the operation of the oil temperature sensor diagnosis device of the embodiment; 4 is a flowchart showing a process of updating elapsed time after engine start in the oil temperature sensor diagnostic device of the embodiment; FIG. 7 is a diagram showing an example of changes in the engine speed, elapsed time after engine start, and amount of subtraction of elapsed time after engine start during oil temperature sensor diagnosis in the oil temperature sensor diagnosis device of the embodiment;

An embodiment of an oil temperature sensor diagnostic device to which the present invention is applied will be described below.
The oil temperature sensor diagnosis device of the embodiment is provided, for example, in a horizontally opposed four-cylinder gasoline direct injection engine mounted as a driving power source in an automobile such as a passenger car.

FIG. 1 is a diagram schematically showing the configuration of an engine having an oil temperature sensor diagnostic device according to an embodiment.
The engine 1 has a crankshaft 10, a cylinder block 20 (20R, 20L), a cylinder head 30 (30R, 30L), an intake system 40, an exhaust system 50, an EGR device 60, an engine control unit (ECU) 100, and the like. It is configured.

The crankshaft 10 is a rotating shaft that serves as an output shaft of the engine 1 .
One end of the crankshaft 10 is connected to a power transmission mechanism such as a transmission (not shown).
The crankshaft 10 is formed with a crankpin arranged eccentrically from the rotation axis.
A piston is connected to the crankpin via a connecting rod (not shown).
A crank angle sensor 11 is provided at the end of the crankshaft 10 to detect the angular position of the crankshaft.
The output of crank angle sensor 11 is transmitted to engine control unit 100 .
The engine control unit 100 calculates the engine speed (crankshaft rotation speed) based on the output of the crank angle sensor 11 .

The cylinder block 20 is divided into two parts, a right cylinder block 20R and a left cylinder block 20L, so as to sandwich the crankshaft 10 from the left and right when the crankshaft 10 is vertically mounted on the vehicle body.
A crankcase portion is provided in the central portion of the cylinder block 20 .
The crankcase portion is a space portion that accommodates the crankshaft 10 .
The crankcase portion is provided with a main bearing that rotatably supports the journal portion of the crankshaft 10 .
Inside the right cylinder block 20R and the left cylinder block 20L, which are arranged on the left and right sides of the crankcase, there are formed, for example, two cylinders (in the case of four cylinders) in which pistons are inserted and reciprocated inside.

A knock sensor 21 is provided in the cylinder block 20 .
Knock sensor 21 has a piezoelectric element that generates an output voltage according to vibration of cylinder block 20 .
The engine control unit 100 can detect the presence or absence of knocking based on the output waveform of the knock sensor 21 peculiar to the occurrence of knocking.

The cylinder heads 30 (right cylinder head 30R, left cylinder head 30L) are provided at ends (left and right ends) of the cylinder block 20 opposite to the crankshaft 10, respectively.
The cylinder head 30 includes a combustion chamber 31, a spark plug 32, an intake port 33, an exhaust port 34, an intake valve 35, an exhaust valve 36, an intake camshaft 37, an exhaust camshaft 38, injectors 39, and the like.
The combustion chamber 31 is formed by recessing a portion of the cylinder head 30 facing the crown surface of the piston, for example, in the shape of a pent roof.
The spark plug 32 generates a spark in response to an ignition signal from the engine control unit 100 to ignite the air-fuel mixture.
The ignition plug 32 is provided in the center of the combustion chamber 31 .

The intake port 33 is a flow path for introducing combustion air (fresh air) into the combustion chamber 31 .
The exhaust port 34 is a passage for discharging burned gas (exhaust gas) from the combustion chamber 31 .
The intake valve 35 and the exhaust valve 36 open and close the intake port 33 and the exhaust port 34 at predetermined valve timings.
For example, two intake valves 35 and two exhaust valves 36 are provided for each cylinder.
The intake valve 35 and the exhaust valve 36 are opened and closed by an intake camshaft 37 and an exhaust camshaft 38 that rotate synchronously at half the rotation speed of the crankshaft 10 .
The cam sprockets of the intake camshaft 37 and the exhaust camshaft 38 are provided with a variable valve timing mechanism (not shown) that advances and retards the phase of each camshaft to change the opening timing and closing timing of each valve. It is
The injector 39 injects fuel into the combustion chamber 31 to form an air-fuel mixture in response to a valve opening signal issued by the engine control unit 100 .
The injector 39 is provided such that a nozzle portion for injecting fuel is exposed into the cylinder from a region on the intake port 33 side of the inner surface of the combustion chamber 31 .

The intake system 40 introduces air into the intake port 33 .
The intake system 40 includes an intake duct 41, a chamber 42, an air cleaner 43, an airflow meter 44, a throttle valve 45, an intake manifold 46, an intake pressure sensor 47, and the like.

The intake duct 41 is a flow path that introduces outside air into the intake port 33 .
The chamber 42 is a space provided in communication with the vicinity of the inlet of the intake duct 41 .
The air cleaner 43 filters air to remove dust and the like.
The air cleaner 43 is provided downstream of a portion of the intake duct 41 that communicates with the chamber 42 .
The airflow meter 44 measures the flow rate of air passing through the intake duct 41 .
The airflow meter 44 is provided near the outlet of the air cleaner 43 .
The output of airflow meter 44 is transmitted to engine control unit 100 .

The throttle valve 45 is a butterfly valve that controls the output of the engine 1 by adjusting the flow rate of air.
The throttle valve 45 is provided in the vicinity of the connecting portion of the intake duct 41 with the intake manifold 46 .
The throttle valve 45 is driven to open and close by an electric throttle actuator (not shown) according to a target throttle opening set by the engine control unit 100 according to the driver's requested torque and the like.
Further, the throttle valve 45 is provided with a throttle sensor for detecting the degree of opening thereof, and its output is transmitted to the engine control unit 100 .
The intake manifold 46 is a branch pipe that distributes air to the intake port 33 of each cylinder.
The intake manifold 46 is provided downstream of the throttle valve 45 .
The intake pressure sensor 47 detects the pressure of air in the intake manifold 46 (intake pressure).
The output of intake pressure sensor 47 is transmitted to engine control unit 100 .

The exhaust system 50 discharges the exhaust gas discharged from the exhaust port 34 to the outside.
The exhaust system 50 includes an exhaust manifold 51, an exhaust pipe 52, a front catalyst 53, a rear catalyst 54, a silencer 55, an air-fuel ratio sensor 56, a rear _O2 sensor 57 and the like.

The exhaust manifold 51 is a collecting pipe that collects the exhaust gas emitted from the exhaust port 34 of each cylinder.
The exhaust pipe 52 is a conduit for discharging the exhaust gas emitted from the exhaust manifold 51 to the outside.
A front catalyst 53 and a rear catalyst 54 are provided in an intermediate portion of the exhaust pipe 52, and each includes a three-way catalyst for purifying HC, NOX, CO, etc. in the exhaust gas.
The front catalyst 53 is provided adjacent to the outlet of the exhaust manifold 51, and the rear catalyst 54 is provided on the outlet side of the front catalyst.
The silencer 55 reduces acoustic energy of the exhaust gas.
The silencer 55 is provided near the outlet of the exhaust pipe 52 .

The air-fuel ratio sensor 56 is provided between the outlet of the exhaust manifold 51 and the inlet of the front catalyst 53 .
A rear O ₂ sensor 57 is provided between the outlet of the front catalyst 53 and the inlet of the rear catalyst 54 .
Both the air-fuel ratio sensor 56 and the rear _O2 sensor 57 detect the amount of oxygen in the exhaust gas by generating an output voltage corresponding to the oxygen concentration in the exhaust gas.
The air-fuel ratio sensor 56 is a linear output sensor capable of detecting oxygen concentrations in a wider range of air-fuel ratios than the rear _O2 sensor 57 .
The outputs of the air-fuel ratio sensor 56 and the rear _O2 sensor 57 are both transmitted to the engine control unit 100 .

The EGR device 60 performs exhaust gas recirculation (EGR) by extracting part of the exhaust gas from the exhaust manifold 51 as EGR gas and introducing it into the intake manifold 46 .
The EGR device 60 includes an EGR flow path 61, an EGR cooler 62, an EGR valve 63, and the like.

The EGR flow path 61 is a pipeline that introduces exhaust gas (EGR gas) from the exhaust manifold 51 to the intake manifold 46 .
The EGR cooler 62 cools the EGR gas flowing through the EGR flow path 61 by heat exchange with the cooling water of the engine 1 .
The EGR cooler 62 is provided in the middle of the EGR flow path 61 .
The EGR valve 63 is a metering valve that adjusts the flow rate of EGR gas passing through the EGR flow path 61 .
The EGR valve 63 is provided downstream of the EGR cooler 62 in the EGR flow path 61 .
The EGR valve 63 has a valve element that is driven by an electric actuator such as a solenoid to open and close. is used to control the opening.

An engine control unit (ECU) 100 comprehensively controls the engine 1 and its accessories.
The engine control unit 100 includes information processing means such as a CPU, storage means such as RAM and ROM, an input/output interface, and a bus connecting these.
The engine control unit 100 is also provided with an accelerator pedal sensor 101 that detects the amount of depression of an accelerator pedal (not shown) by the driver.
The engine control unit 100 has a function of setting the driver's requested torque based on the output of the accelerator pedal sensor 101 and the like.
The engine control unit 100 adjusts the throttle valve opening, supercharging pressure, fuel injection amount, fuel injection timing, ignition timing, valve timing, etc. so that the torque actually generated by the engine 1 approaches the set driver required torque. Control.
The engine control unit 100 also functions as a diagnostic value setting section and an abnormality determination section in the oil temperature sensor diagnostic device of the embodiment.
These functions will be described in detail later.

Further, the engine control unit 100 is connected to an oil temperature sensor 110, an outside air temperature sensor 120, an idle stop control unit 130, and the like.
Oil temperature sensor 110 is a temperature sensor that detects the temperature of lubricating oil (oil) of engine 1 .
The outside air temperature sensor 120 is a temperature sensor that detects the outside air temperature of the vehicle (the temperature of the atmosphere around the vehicle).

The idle stop control unit 130 executes idle stop control to automatically stop the engine 1 when the operating conditions of the engine 1 and the vehicle satisfy predetermined idle stop conditions.
The idling stop conditions include, for example, that the vehicle is stopped, that the driver requested torque is substantially zero (accelerator is off), and that the cooling water temperature of the engine 1 is a predetermined value (eg, 40° C.) or higher. the brake master cylinder hydraulic pressure is equal to or higher than a predetermined value; the steering angle is equal to or lower than a predetermined value; the state of charge (SOC) of the restarting battery is equal to or higher than a predetermined value; It may be equal to or less than a predetermined value.
The engine control unit 100 stops fuel injection and ignition in the engine 1 and stops the engine 1 when all these conditions are satisfied.

Here, for example, when the engine 1 is cold-started (cold start after soaking) from a state where the outside air temperature is about 20° C., the temperatures of the cooling water and the oil are substantially the same as the outside air temperature. equal. After that, in the initial period of warm-up (immediately after start-up), the temperature of the cooling water is raised before the temperature of the oil.
In the embodiment, as will be described later, the characteristic diagnosis of the oil temperature sensor 110 is performed until the oil temperature reaches 45°C. , the idle stop control can be executed.
That is, in the embodiment, idle stop control may intervene during diagnosis of oil temperature sensor 110 .

Further, the idle stop control unit 130 executes restart control for automatically restarting the engine 1 when a predetermined restart condition is satisfied during execution of the idle stop control.
As the restart condition, for example, at least one of the idle stop conditions is unsatisfied.
When the restart condition is satisfied, the engine control unit 100 causes a starter motor (not shown) to rotate (crank) the crankshaft, restart fuel injection and ignition, and restart the engine 1 .

The engine 1 is equipped with a lubricating device which will be described below.
FIG. 2 is a block diagram schematically showing the configuration of the lubricating device of the engine of FIG. 1. As shown in FIG.
As shown in FIG. 2, the lubricating device 200 includes an oil pan 210, an oil strainer 220, an oil pump 230, an oil filter 240, and the like.

Oil pan 210 is a tray-shaped member provided below cylinder block 20 .
The oil pan 210 stores oil, which is lubricating oil for the engine 1 and working oil for the variable valve timing mechanism and the hydraulic lash adjuster.
Oil pan 210 is provided with oil temperature sensor 110 that detects the temperature of oil (oil temperature).

The oil strainer 220 is an oil intake portion connected to the suction port of the oil pump 230 .
An inlet-side end of oil strainer 220 is disposed inside oil pan 210 .
The oil strainer 220 has the function of removing relatively large pieces of foreign matter in the oil by means of a screen such as wire mesh.

The oil pump 230 pressurizes the oil taken in via the oil strainer 220 and conveys (pumps) it to each part of the engine 1 .
The oil pump 230 is, for example, of a trochoid rotor type driven by the crankshaft 10 of the engine 1 .
Oil pump 230 has an inner rotor and an outer rotor combined within a pump body.
The inner rotor rotates with respect to the outer rotor in conjunction with the rotation of the crankshaft 10 .
The oil pump 230 also includes a relief valve (not shown) that prevents the hydraulic pressure on the discharge side from becoming excessive.

The oil filter 240 is of a full-flow cartridge type that filters the oil discharged by the oil pump 230 using, for example, a paper element.
The oil discharged from the oil filter 240 is pressure-fed to oil galleries (oil passages) (not shown) formed inside the right cylinder block 20R and the left cylinder block 20L, respectively.

A part of the oil supplied to the right cylinder block 20R and the left cylinder block 20L is supplied to journal bearings and connecting rod bearings (not shown) to lubricate these bearings.
Thereafter, this oil returns to the oil pan 210 by natural fall after leaking from the lubrication target.
Some of the oil also lubricates the small end of the connecting rod and the inner wall of the cylinder by splashing.

Another part of the oil supplied to the right cylinder block 20R is also supplied to the right cylinder head 30R and returns to the oil pan 210 after lubricating the valve drive system and the like.
Another part of the oil supplied to the left cylinder block 20L is also supplied to the left cylinder head 30L and returns to the oil pan 210 after lubricating the valve driving system and the like.

The operation of the oil temperature sensor diagnostic device of the embodiment will be described below.
FIG. 3 is a flow chart showing the operation of the oil temperature sensor diagnostic device of the embodiment.
Each step will be described in order below.

<Step S01: Judgment of engine speed>
The engine control unit 100 detects the engine speed (rotational speed of the crankshaft 10) based on the output of the crank angle sensor 11. FIG.
If the engine speed exceeds the threshold value set considering that the engine is in a normal operating state, the process proceeds to step S02, otherwise step S01 is repeated.
Here, as the threshold value, for example, the lower limit number of revolutions during idling (for example, about 350 rpm) can be used.

<Step S02: Judgment of Oil Temperature at Startup>
The engine control unit 100 compares the oil temperature at engine start calculated based on the output of the oil temperature sensor 110 with a preset threshold value.
The threshold value is set substantially equal to or slightly higher than the outside air temperature, for example, considering the oil temperature at the time of cold start.
If the oil temperature at startup is less than the threshold value, the process proceeds to step S03; otherwise, the process returns to step S01 and the subsequent processes are repeated.

<Step S03: Judgment of Oil Temperature Judgment Value>
Engine control unit 100 compares the current oil temperature (detected oil temperature of oil temperature sensor 110) calculated based on the output of oil temperature sensor 110 with a preset determination value.
The determination value is set, for example, in consideration of the oil temperature when the warm-up of the engine 1 is substantially completed, and is set to about 45°C, for example.
If the current oil temperature is less than the judgment value, the process proceeds to step S04; otherwise, the process proceeds to step S07.

<Step S04: Judgment of elapsed time after engine start>
The engine control unit 100 is a parameter that correlates with the elapsed time after the start of the engine 1 (not the actual elapsed time itself as described later), and the elapsed time after the engine start that functions as a diagnostic value in abnormality determination. Considering the time required for warm-up in 1 (the time required for the oil temperature to reach the judgment value in normal conditions), it is compared with a preset threshold value.
If the elapsed time after starting the engine is equal to or greater than the threshold value, the process proceeds to step S06; otherwise, the process proceeds to step S05.

<Step S05: Update elapsed time after engine start>
The engine control unit 100 updates the elapsed time since engine start.
The processing for updating the elapsed time after engine start will be described later in detail.
After that, the process returns to step S03 and the subsequent processes are repeated.

<Step S06: Establishment of Abnormality Determination>
The engine control unit 100 establishes an abnormality determination indicating that the oil temperature sensor 110 is malfunctioning (no output change corresponding to the assumed oil temperature change is obtained).
When the abnormality determination is established, a warning light (not shown) or the like notifies a user such as a driver that a failure has occurred.
Further, each control using the oil temperature detected by the oil temperature sensor 110 shifts to fail-safe control on the premise that the oil temperature cannot be obtained.
After that, the series of processing ends.

<Step S07: Establishment of normal determination>
Engine control unit 100 establishes a normality determination indicating that oil temperature sensor 110 is normal.
After that, the series of processing ends.

Hereinafter, the processing for updating the elapsed time after engine start (see step S05) will be described.
FIG. 4 is a flowchart showing a process of updating the elapsed time after engine start in the oil temperature sensor diagnostic device of the embodiment.
Each step will be described in order below.

<Step S51: Judgment during idle stop execution>
The engine control unit 100 determines whether the engine 1 is stopped by idle stop control.
If the engine 1 is stopped, the process proceeds to step S53, and if the engine 1 is in operation, the process proceeds to step S52.

<Step S52: Elapsed time count up after engine start>
The engine control unit 100 adds (counts up) the elapsed time after starting the engine according to the actual elapsed time.
After that, the series of processing ends. (Proceed to step S03 in FIG. 3)

<Step S53: Outside temperature detection>
Engine control unit 100 acquires information about the outside temperature based on the output of outside temperature sensor 120 .
After that, the process proceeds to step S54.

<Step S54: Elapsed time subtraction after engine start>
The engine control unit 100 calculates a subtraction amount to be subtracted from the elapsed time after starting the engine.
The subtraction amount of the elapsed time after engine start is set to increase as the stop time of the engine 1 increases, for example, it increases in proportion to the stop time.
Considering that the lower the outside air temperature is, the more oil is cooled while the engine is stopped, the amount of subtraction for the elapsed time after the engine starts increases as the outside air temperature decreases. is set to be smaller).
Such a subtraction amount of the elapsed time after starting the engine can be calculated, for example, when the engine 1 is restarted.
After calculating the subtraction amount of the elapsed time after engine start, the engine control unit 100 subtracts it from the immediately preceding elapsed time after engine start.
After that, the series of processing ends. (Proceed to step S03 in FIG. 3)

FIG. 5 is a diagram showing an example of transitions of the engine speed, elapsed time after engine start, and subtraction amount of elapsed time after engine start during oil temperature sensor diagnosis in the oil temperature sensor diagnosis device of the embodiment.
The vertical axis indicates the engine speed, the elapsed time after the engine start, and the subtraction amount of the elapsed time after the engine start, and the horizontal axis indicates the time.
At time T1, the engine 1 is cold-started.
After that, the elapsed time after starting the engine increases in proportion to the elapsed operating time.
At time T2, the idle stop control is executed and the engine 1 is temporarily stopped.
At this time, the addition of the elapsed time after engine start is stopped.

At time T3, the restart control is executed and the engine 1 is restarted.
At this time, the elapsed time after the engine start is subtracted by a subtraction amount set according to the stop time of the engine 1 by idle stop control.
In FIG. 5, the amount of subtraction in the normal state is indicated by a solid line, the amount of subtraction when the outside air temperature is lower than in the normal state is indicated by a dotted line, and the amount of subtraction when the outside temperature is higher than in the normal state is indicated by a dashed line.
As shown in FIG. 5, the subtraction amount is set to increase substantially in proportion to the engine stop time due to idle stop, and to increase (decrease as the outside temperature rises) as the outside temperature drops. ing.
The elapsed time after starting the engine is reduced by the calculated subtraction amount, and then added again according to the operating time of the engine 1 .

In FIG. 5, the dotted line indicates the elapsed time after the engine start when the subtraction associated with the idle stop control described above is not performed.
If the subtraction associated with the idle stop control is not performed, the elapsed time after the engine start is simply added during the period in which the engine 1 is stopped, there is no heat generated by combustion, and the heat input to the oil is substantially interrupted. Since the operation continues, there is a concern that if the characteristic diagnosis of the oil temperature sensor is performed based on the elapsed time after the engine is started, the diagnosis may not be performed appropriately.
For example, although the oil temperature sensor 110 is normal, an erroneous diagnosis may occur.
On the other hand, in the embodiment, considering the interruption of heat input to the oil when the engine is stopped and the influence of cooling of the oil pan 210 by the outside air, the oil temperature decreases according to the engine stop time during the idle stop. The oil temperature sensor 110 can be diagnosed by properly reflecting the physical phenomenon that

As described above, according to this embodiment, the following effects can be obtained.
(1) When the engine is stopped by idle stop control, by stopping the addition of the elapsed time after engine start (diagnostic value in the embodiment), the oil temperature behavior when the engine is stopped without heat generated by combustion in the engine 1 is measured. It is appropriately reflected in the elapsed time, and the diagnostic accuracy of the oil temperature sensor 110 can be improved.
(2) When the engine is stopped by idling stop control, by subtracting the elapsed time after engine start by the subtraction amount corresponding to the stop time, the phenomenon that the oil is cooled by heat radiation from the oil pan 210 or the like to the outside air when the engine is stopped is prevented. , the elapsed time after the engine start can be reflected, and the diagnostic accuracy of the oil temperature sensor 110 can be further improved by appropriately setting the elapsed time after the engine start.
(3) By changing the subtraction amount of the elapsed time after engine start according to the outside air temperature, it is possible to more appropriately reflect the decrease in oil temperature while the engine is stopped in the diagnostic value, and the diagnostic accuracy of the oil temperature sensor 110. can be further improved.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, which are also within the technical scope of the present invention.
(1) The configurations of the oil temperature sensor diagnosis device and the engine are not limited to the above-described embodiments, and can be changed as appropriate.
For example, in the embodiments, the engine is a horizontally opposed direct injection gasoline engine, but the invention is applicable to other types of internal combustion engines.
For example, the cylinder layout, the number of cylinders, the fuel injection method, the presence or absence of a supercharger, etc. are not particularly limited.
Moreover, the present invention is applicable not only to gasoline engines but also to engines using fuels other than gasoline (diesel engines, etc.).
Also, in the embodiment, the oil temperature sensor is provided in the oil pan, but the installation location of the oil temperature sensor is not particularly limited, and it is possible to provide it at any location in the lubricating oil passage.
(2) In the embodiment, the subtraction amount of the elapsed time after engine start is changed based on the outside temperature. may be changed.
For example, the subtraction amount may be changed according to the temperature of fresh air in the engine 1 (intake air temperature).
Further, instead of acquiring the outside air temperature on the vehicle with an outside air temperature sensor, information on the outside air temperature may be acquired from the outside using, for example, weather information using a communication device.
(3) In the embodiment, the diagnosis is made based on the elapsed time after the engine start until the oil temperature reaches the set oil temperature. Diagnosis may be based on quantity.

1 engine 10 crankshaft 11 crank angle sensor 20 cylinder block 20R right cylinder block 20L left cylinder block 21 knock sensor 30 cylinder head 30R right cylinder head 30L left cylinder head 31 combustion chamber 32 spark plug 33 intake port 34 exhaust port 35 intake valve 36 exhaust valve 37 intake camshaft 38 exhaust camshaft 39 injector 40 intake system 41 intake duct 42 chamber 43 air cleaner 44 air flow meter 45 throttle valve 46 intake manifold 47 intake pressure sensor 50 exhaust system 51 exhaust manifold 52 exhaust pipe 53 front catalyst 54 rear catalyst 55 silencer 56 air-fuel ratio sensor 57 rear _O2 sensor 60 EGR device 61 EGR flow path 62 EGR cooler 63 EGR valve 100 engine control unit (ECU)
101 accelerator pedal sensor 110 oil temperature sensor 120 outside air temperature sensor 130 idle stop control unit 200 lubricating device 210 oil pan 220 oil strainer 230 oil pump 240 oil filter

Claims (2)

engine and
an oil temperature sensor that detects the oil temperature of the lubricating oil of the engine;
and an idle stop control unit that performs idle stop control to stop the engine when predetermined idle stop conditions are satisfied and automatically restart the engine when predetermined restart conditions are satisfied. An oil temperature sensor diagnosis device for detecting an abnormality in the oil temperature sensor,
a diagnostic value setting unit for setting a diagnostic value for diagnosing an abnormality of the oil temperature sensor, which is a value added in correlation with the elapsed operating time after the cold start of the engine;
When the diagnostic value is greater than or equal to a predetermined value while the oil temperature detected by the oil temperature sensor is less than a predetermined judgment value, the oil temperature sensor is determined to be abnormal and the oil temperature detected by the oil temperature sensor is determined to be abnormal. an abnormality determination unit that determines that the oil temperature sensor is normal when the oil temperature is equal to or higher than the determination value ;
The idling stop control unit performs the idling stop control when the predetermined idling stop condition is satisfied even before the determination of the abnormality or the normality by the abnormality determination unit is established after the cold start of the engine. is a
The diagnostic value setting unit stops addition of the diagnostic value when the idling stop control is performed before the determination of the abnormality or the normality by the abnormality determination unit is established, and the engine is stopped by the idling stop control. An oil temperature sensor diagnostic device that subtracts from the diagnostic value a subtraction amount that increases according to the stop time. The oil temperature sensor diagnosis device includes an outside temperature detection unit that detects a parameter correlated with the outside temperature of the vehicle,
The oil temperature sensor diagnostic device according to claim 1, wherein the diagnostic value setting unit increases the subtraction amount as the outside air temperature decreases.

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