JP2010025024A - Abnormality detector of temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality detector of a temperature sensor which avoids erroneous determination and performs the detection of the abnormality of a temperature sensor at an increased frequency, in the abnormality detector of the temperature sensor performing the detection of the abnormality of a temperature sensor when an engine stop period of an internal combustion engine exceeds a threshold. <P>SOLUTION: An electronic controller of an internal combustion engine 10 stores data by making parameters such as a cooling water temperature and a lubricating oil temperature at the time of engine stoppage associated with an appropriate soaking time period that makes a difference between the cooling water temperature and the lubricating oil temperature sufficiently small at the next start of the engine. The electronic controller detects the parameters during the engine stoppage, sets the threshold of the soaking time period suitable for the temperature of the internal combustion engine at each time during the engine stop using the detected parameters and the data, and performs the detection of the abnormality of an oil temperature sensor 54 when the soaking time period measured by a soaking timer exceeds the set threshold. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an abnormality detection device for a temperature sensor applied to an internal combustion engine.

  Sensors related to the internal combustion engine include a water temperature sensor that detects the temperature of cooling water that cools the cylinder head and the like, an oil temperature sensor that detects the temperature of the lubricating oil of the internal combustion engine, and an outside air temperature sensor that detects the temperature of the outside air of the internal combustion engine Various temperature sensors are used to grasp the operating state of the internal combustion engine. In an internal combustion engine using such a temperature sensor, if the detection error becomes large, it becomes difficult to grasp an accurate operating state. Therefore, an abnormality detection process for each temperature sensor is appropriately performed in order to avoid such a state (for example, Patent Document 1).

In the abnormality detection process of the oil temperature sensor, a technique for detecting the presence / absence of abnormality using a correlation between the coolant temperature and the lubricating oil temperature is known. For example, when the stop period of the internal combustion engine becomes sufficiently long, the cooling water temperature and the lubricating oil temperature are stabilized (saturated) with each other. Therefore, the estimated value of the lubricating oil temperature is set on the condition that this is a stable state. An abnormality of the oil temperature sensor can be detected by calculating from the detection value of the water temperature sensor and comparing the estimated value with the detection value of the oil temperature sensor.
JP 2004-339969 A

  By the way, since the coolant temperature is more likely to change than the lubricating oil temperature immediately after the internal combustion engine is started, when a special driver operation is performed in which the start and stop of the internal combustion engine are repeated in a short period of time. Will increase the gap between the cooling water temperature and the lubricating oil temperature. In the above-described abnormality detection processing of the oil temperature sensor, it is necessary to reduce the difference between the cooling water temperature and the lubricating oil temperature under any circumstances including special driver operations. In order to uniformly set the time from the time to the time of abnormality detection (the above-mentioned stop period), the stop period must be lengthened. As a result, the abnormality detection process cannot be executed unless the stop period elapses, so that not only the time required for the process increases, but also a new problem that the abnormality detection frequency of the temperature sensor decreases occurs.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to make an erroneous determination in an abnormality detection device for a temperature sensor that detects an abnormality of the temperature sensor when the stop period of the internal combustion engine exceeds a threshold value. An object of the present invention is to provide a temperature sensor abnormality detection device that avoids the problem and increases the temperature sensor abnormality detection frequency.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1, when the stop period, which is the time from when the internal combustion engine is stopped to when it is started, exceeds a threshold for obtaining a correlation between the lubricating oil temperature and the coolant temperature in the internal combustion engine, Detects whether there is an abnormality in the temperature sensor by determining whether the difference between the detected value of the oil temperature sensor that detects the lubricating oil temperature and the detected value of the water temperature sensor that detects the cooling water temperature is a reference value. An abnormality detection device for a temperature sensor that performs the threshold based on the deviation width at the time of stopping so that the threshold value becomes shorter as the deviation width between the lubricating oil temperature and the cooling water temperature at the time of stopping becomes smaller. The gist is to set.

The correlation between the cooling water temperature and the lubricating oil temperature after the start of the internal combustion engine is reproduced in a shorter time as the deviation width between the cooling water temperature and the lubricating oil temperature when the internal combustion engine is stopped decreases. According to the present invention, the smaller the deviation width is, the shorter the time (threshold) from the stop time to the abnormality detection time, that is, the required time required for the abnormality detection is set. Therefore, with respect to the required time, a shorter time can be realized within a range in which the correlation between the cooling water temperature and the lubricating oil temperature is guaranteed. Therefore, it is possible to shorten the time required for detecting an abnormality while avoiding an erroneous determination due to a large difference between the cooling water temperature and the lubricating oil temperature at the start. Also, since the threshold value of the engine stop period suitable for the time is set with the temperature at the time of engine stop as a parameter, the threshold value of the engine stop period is set uniformly so as to correspond to all conditions. In addition, the abnormality detection frequency of the temperature sensor can be increased.

The gist of the invention described in claim 2 is to set the threshold value for each outside air temperature of the internal combustion engine.
The correlation between the cooling water temperature and the lubricating oil temperature after the start of the internal combustion engine may be reproduced in a time corresponding to the heat balance between the cooling system or the lubricating system and the outside air. According to the present invention, since the threshold value is set for each outside air temperature even in such a case, the abnormality detection frequency of the temperature sensor can be further increased while avoiding erroneous determination more reliably.

The gist of the invention described in claim 3 is that the threshold value is set to “0” when the deviation width at the time of the stop is a value indicating a correlation between the lubricating oil temperature and the cooling water temperature. .
According to the present invention, when it is determined that the difference between the coolant temperature and the lubricating oil temperature when the internal combustion engine is stopped is sufficiently small, the minimum value “0” is set as the threshold value. The time required for detection can be further shortened, and the abnormality detection frequency of the temperature sensor can be further increased.

  According to a fourth aspect of the present invention, the estimated value of the lubricating oil temperature when a predetermined operation time has elapsed from the start time is calculated using the detected value of the water temperature sensor at the start time of the internal combustion engine. Whether or not the oil temperature sensor is abnormal is detected by determining whether or not the difference between the detected value of the oil temperature sensor and the estimated value when the predetermined operating time has elapsed is a reference value. This is the gist.

  According to the present invention, since abnormality detection is performed when a predetermined operation time has elapsed since the start of the internal combustion engine, it is possible to provide a degree of freedom regarding the opportunity of abnormality detection. For example, abnormality detection is performed even in a steady operation state. be able to. Even when such a predetermined operating time is provided, erroneous determination can be avoided when detecting an abnormality of the oil temperature sensor, and the abnormality detection frequency can be increased by setting the above-described threshold.

(First embodiment)
The first embodiment according to the present invention will be described below. FIG. 1 shows a schematic configuration of an internal combustion engine 10, a lubrication system 40 that supplies lubricating oil to the internal combustion engine 10, a temperature sensor abnormality detection device, and the like in the present embodiment.

  The internal combustion engine 10 includes a cylinder block 11, and a piston 13 is accommodated in a cylinder 12 of the cylinder block 11 so as to be able to reciprocate. The piston 13 is connected to a crankshaft 15 that is an output shaft of the internal combustion engine 10 via a connecting rod 14. The reciprocating motion of the piston 13 is converted into the rotational motion of the crankshaft 15 by the connecting rod 14.

An intake passage 20 for sucking air into the combustion chamber 16 and an exhaust passage 21 for discharging exhaust gas after combustion from the combustion chamber 16 are connected to the combustion chamber 16 of each cylinder 12. The intake port of the intake passage 20 is provided with an intake valve 22 that opens and closes according to the rotation of the crankshaft 15. The intake valve 22 is opened at a predetermined valve opening timing and valve opening time, whereby the combustion chamber 16 is opened. Air is introduced into the interior. The exhaust port of the exhaust passage 21 is provided with an exhaust valve 23 that opens and closes according to the rotation of the crankshaft 15. The exhaust valve 23 opens at a predetermined valve opening timing and valve opening time. The air-fuel mixture burned in is exhausted as exhaust gas.

  The combustion chamber 16 is provided with an injector 17 that injects fuel in accordance with the rotation of the crankshaft 15. The injector 17 injects fuel at a predetermined injection timing and injection time, so that the intake valve 22 is controlled. An air-fuel mixture composed of the air introduced through the fuel and the fuel is generated in the combustion chamber 16. The combustion chamber 16 is provided with an ignition plug 18 that ignites the mixture according to the rotation of the crankshaft 15. The ignition plug 18 ignites at a predetermined ignition timing, whereby the mixture in the combustion chamber 16 is ignited. Is burned, and the pressure of the combustion gas, which is the working fluid, is converted into the rotational movement of the crankshaft 15 through the reciprocating movement of the piston 13.

  An electric throttle valve 31 that is opened and closed by an actuator 32 is provided in the middle of the intake passage 20. The throttle valve 31 is opened at a predetermined throttle opening, so that the amount of intake air into the combustion chamber 16 is reduced. Adjusted.

  In the cylinder block 11, a water jacket 19 in which engine cooling water for cooling the cylinder block 11 and the like heated by the engine combustion heat by combustion in the combustion chamber 16 circulates is formed so as to surround each cylinder 12. . The internal combustion engine 10 includes an electric water pump (not shown), and the engine cooling water circulates in the water jacket 19 and the like by driving the electric water pump.

  The lubrication system 40 of the internal combustion engine 10 is formed as a part of the crankcase of the crankshaft 15 and includes an oil pan 41 connected to the cylinder block 11 and a lubricating oil supply device 42. The lubricating oil supply device 42 includes an oil pump, a filter, an oil jet mechanism (all not shown), and the like. The lubricating oil in the oil pan 41 is sucked by the oil pump through the filter and supplied to the oil jet mechanism. When lubricating between the piston 13 and the inner peripheral surface of the cylinder 12, the lubricating oil thus supplied to the oil jet mechanism is supplied from the same mechanism to the inner peripheral surface of the cylinder 12. Thereafter, as the piston 13 reciprocates, the lubricating oil is scraped downward from the inner peripheral surface of the cylinder 12 and finally returned to the oil pan 41. Then, the scraped lubricating oil is mixed with the lubricating oil in the oil pan 41 and then used for lubricating the internal combustion engine 10 again. The lubricating oil supplied to the inner peripheral surface of the cylinder 12 and used for lubricating the piston 13 is returned to the oil pan 41 after the temperature rises due to engine combustion heat. Therefore, when the circulation of the lubricating oil by the lubricating system 40 is started as the engine is started, the average temperature of the entire lubricating oil gradually increases until the lubricating oil shifts to a thermal equilibrium state.

  Various controls of the internal combustion engine 10 are performed by an electronic control device 50 which is a control device mounted on a vehicle. The electronic control unit 50 includes a calculation unit that executes calculation processing related to the control of the internal combustion engine 10, a program and data necessary for various controls, and a storage unit that temporarily stores calculation results of the calculation unit, An input / output port for inputting / outputting signals to / from the outside is provided. The electronic control device 50 has a built-in soak timer 50a. The soak timer 50a functions as a measuring unit that measures a soak time that is an elapsed time from the engine stop of the internal combustion engine 10 to the next engine start.

Detection signals from various sensors are input to the input port of the electronic control unit 50 in order to detect the driving state of the vehicle on which the internal combustion engine 10 is mounted. Specifically, a detection signal related to the intake air amount is input from the air flow meter 51 provided in the intake passage 20 to the input port, and a detection signal related to the throttle opening is received from the throttle sensor 52 provided in the throttle valve 31. Input to the input port. A detection signal relating to the coolant temperature, which is the temperature of the engine coolant circulating in the water jacket 19, is input from the coolant temperature sensor 53 provided in the cylinder block 11. From the oil temperature sensor 54 provided in the oil pan 41, a detection signal relating to the lubricating oil temperature, which is the temperature of the lubricating oil stored in the oil pan 41, is input. A detection signal related to the outside air temperature of the internal combustion engine 10 is input from the outside air temperature sensor 55 that detects the temperature of the outside air of the internal combustion engine 10. Furthermore, from the ignition switch 56 that is switched to one of four switching positions such as “off”, “accessory”, “on”, and “start” by the driver of the automobile on which the internal combustion engine 10 is mounted, A detection signal corresponding to the switching position is input. That is, based on the detection signal from the ignition switch 56, the electronic control unit 50 measures the soak time of the internal combustion engine 10 at that time by the soak timer 50a.

  On the other hand, the output port of the electronic control unit 50 is electrically connected to the injector 17, the spark plug 18, the actuator 32 for driving the throttle valve 31, the lubricating oil supply device 42, and the like. The electronic control unit 50 detects the operating state of the internal combustion engine 10 based on the detection signals from the respective sensors, and outputs a command signal corresponding to the operating state at that time to each of the above units via the output port. The electronic control unit 50 executes start / stop control of the internal combustion engine 10, throttle opening control of the throttle valve 31, ignition control of the ignition plug 18, fuel injection control by the injector 17, and the like based on the operating state.

  In addition to the various controls described above, the electronic control device 50 executes an abnormality detection process for detecting an abnormality of the oil temperature sensor 54 based on detection signals from the various sensors. Abnormality of the oil temperature sensor 54 is detected using a correlation between the coolant temperature after the engine is started and the lubricating oil temperature. More specifically, the electronic control unit 50 stores a correlation map that associates the coolant temperature and the lubricating oil temperature after the engine is started. This correlation map is a map showing respective temperature changes after the engine is started from a state where the deviation width between the coolant temperature and the lubricating oil temperature is sufficiently small when the engine is started and is substantially equal (stable state). The electronic control unit 50 detects the coolant temperature when starting the engine, and based on the detected coolant temperature and the correlation map, sets the lubricating oil temperature when a predetermined operation time has elapsed from the start of the engine to a predetermined range. Estimate with. The electronic control unit 50 detects the actual lubricating oil temperature when the predetermined operating time has elapsed, and determines that the oil temperature sensor 54 is abnormal when the detected lubricating oil temperature is outside the estimated temperature range. A warning light (not shown) is turned on. The predetermined operation time may be, for example, a time until it is determined that the warm-up of the internal combustion engine 10 is completed based on detection signals of various sensors, and is generally a number corresponding to this type of time. It may be an arbitrary value selected from a short-term range of 100 seconds or less. The stable state is not limited to a state in which the coolant temperature and the lubricating oil temperature substantially coincide with each other, and may be a state in which these two temperatures fluctuate with correlation.

  The abnormality detection process of the oil temperature sensor 54 is executed when the soak time, which is the engine stop period, is equal to or greater than a threshold value. The electronic control unit 50 stores the coolant temperature and the lubricating oil temperature when the internal combustion engine 10 is stopped, and sets the soak time threshold using these two temperatures as parameters. More specifically, the electronic control unit 50 associates the deviation width between the cooling water temperature and the lubricating oil temperature when the engine is stopped and the shortest soak time (the threshold value) until the deviation width becomes stable. (Threshold data) is stored. The threshold value included in the threshold data is not limited to the shortest time until the stable state is reached, and may be a value that becomes shorter as the deviation width between the cooling water temperature and the lubricating oil temperature when the engine is stopped is smaller.

FIG. 2 is an example in which the threshold data is graphed, in which the lubricating oil temperature when the engine is stopped is 30 ° C., and the deviation width between the cooling water temperature and the lubricating oil temperature when the engine is stopped, The relationship with the threshold according to time is shown. In the internal combustion engine 10, heat exchange is always performed between the cooling water and the lubricating oil via a rigid body having high thermal conductivity. Since the cooling water temperature and the lubricating oil temperature at the start of the internal combustion engine 10 have such heat exchange, the smaller the deviation width at the time of the preceding stop, the sooner the stable state is reached. Therefore, as shown in FIG. 2, the threshold value data is defined such that the threshold value decreases as the deviation width between the lubricating oil temperature and the cooling water temperature when the engine is stopped decreases.

  The electronic control unit 50 stores the cooling water temperature and lubricating oil temperature at that time as parameters when the internal combustion engine 10 is stopped, and refers to the threshold data when the engine is started, and stores the cooling water temperature and lubrication stored when the engine is stopped. Determine a threshold based on oil temperature. By determining such a threshold value, the shortest threshold value is set in order to stabilize the cooling water temperature and the lubricating oil temperature. Therefore, an erroneous determination can be avoided during the abnormality detection process, and the time required for the abnormality detection process can be shortened compared to the case where the soak time threshold value is uniformly set to correspond to all conditions, and the abnormality of the oil temperature sensor 54 can be reduced. The detection frequency can be increased.

As is apparent from FIG. 2, in the present embodiment, when the divergence between the cooling water temperature and the lubricating oil temperature at the time of engine stop is less than the lower limit value T ₁ is at the start the engine immediately after stoppage It is already determined that the deviation width between the cooling water temperature and the lubricating oil temperature is sufficiently small, and the soak time threshold is defined as “0”. That is, the abnormality detection process of the oil temperature sensor 54 is always executed at the next engine start. By doing so, the abnormality detection frequency of the oil temperature sensor 54 can be further increased.

Next, a control routine for the abnormality detection process of the oil temperature sensor 54 will be described with reference to FIG. FIG. 3 is a flowchart for explaining the control routine.
First, when an ignition operation is performed by the driver and the internal combustion engine 10 is stopped (step S101), the electronic control unit 50 starts counting the soak time by the soak timer 50a and sets a threshold value for the soak time. As the parameters, the coolant temperature and the lubricating oil temperature when the engine is stopped are detected and stored (step S102).

  Next, when the ignition switch 56 is operated by the driver and the internal combustion engine 10 is started (step S103), the electronic control unit 50 performs a suitable operation at that time based on the parameters stored in step S102 and the threshold data. A threshold value is set (step S104).

  The electronic control unit 50 compares the set soak time threshold with the actual soak time measured by the soak timer 50a, and determines whether or not the actual soak time is equal to or greater than the threshold (step S105). When the actual soak time is equal to or greater than the threshold (step S105: YES), the electronic control unit 50 detects the coolant temperature when the internal combustion engine 10 is started, and only the predetermined operation time from the start of the engine. The temperature range of the lubricating oil temperature after elapse is estimated based on the correlation map. Then, the electronic control unit 50 detects the actual lubricating oil temperature after elapse of a predetermined operation time, and compares the detected lubricating oil temperature with the estimated lubricating oil temperature range so that the oil temperature sensor 54 Abnormality detection is executed (step S106), and when an abnormality of the oil temperature sensor 54 is detected, a warning lamp (not shown) is turned on, and this routine ends.

On the other hand, when the actual soak time does not exceed the threshold value in step S105 (step S105: NO), the electronic control unit 50 ends this routine.
As described above, according to the first embodiment, the following effects can be obtained.

(1) The electronic control unit 50 stores the coolant temperature and the lubricating oil temperature when the internal combustion engine 10 is stopped, and sets a threshold based on the stored temperatures and threshold data when the internal combustion engine 10 is started. This makes it possible to set a suitable threshold according to each parameter when the engine is stopped, compared with the case where the soak time threshold is uniformly set so as to correspond to all conditions, thereby reducing the time required for the abnormality detection process. The frequency of detecting the abnormality of the oil temperature sensor 54 can be increased while avoiding erroneous determination.

(2) When divergence between the cooling water temperature and the lubricating oil temperature at the time of engine stop is less than the lower limit value T ₁ has a threshold value of the soak period as "0". By doing so, the abnormality detection process of the oil temperature sensor 54 is always executed at the next engine start, so that the abnormality detection frequency of the oil temperature sensor 54 can be further increased.
(Second Embodiment)
A second embodiment of the temperature sensor abnormality detection device according to the present invention will be described below with reference to FIG. In the second embodiment, only the configuration different from that of the first embodiment will be described in detail, and the detailed description of the same configuration will be omitted.

  In the second embodiment, the soak time threshold is set using the cooling water temperature, lubricating oil temperature, and outside air temperature when the engine is stopped as parameters. The electronic control unit 50 associates the deviation width between the cooling water temperature and the lubricating oil temperature when the engine is stopped and the shortest soak time (the threshold value) until the deviation width becomes stable for each outside air temperature. Data (threshold data) is stored. The threshold value included in the threshold data is not limited to the shortest time until the stable state is reached, and may be a value that becomes shorter as the deviation width between the cooling water temperature and the lubricating oil temperature when the engine is stopped is smaller.

  FIG. 4 is an example of a graph of the threshold data, and shows a case where the lubricating oil temperature is 20 ° C. when the engine is stopped. As apparent from FIG. 4, in the threshold data, the soak time threshold is specified to be longer as the outside air temperature is lower, even if the difference between the cooling water temperature and the lubricating oil temperature is the same value. This is because after the internal combustion engine 10 is stopped, the cooling water temperature and the lubricating oil temperature converge to the outside air temperature while reducing the deviation width.

  The electronic control unit 50 stores the cooling water temperature, the lubricating oil temperature, and the outside air temperature as parameters when the internal combustion engine 10 is stopped, and stores each parameter stored when the engine is stopped with reference to the threshold value data when starting the engine. Determine a threshold based on temperature. By determining such a threshold value, in order to make the cooling water temperature and the lubricating oil temperature stable, the shortest threshold value is set in consideration of the outside air temperature related to these fluctuations. Therefore, the time required for the abnormality detection process can be shortened more suitably, and the abnormality detection frequency can be further increased while avoiding erroneous determination more reliably.

As described above, according to the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.
(3) In the second embodiment, the soak time threshold is set using the outside air temperature as a parameter in addition to the cooling water temperature and the lubricating oil temperature when the engine is stopped. As a result, the soak time threshold value can be set to a more suitable value, so that the time required for the abnormality detection process can be shortened more appropriately, and the abnormality detection frequency of the oil temperature sensor 54 can be increased while avoiding erroneous determination more reliably. It can be further enhanced.

In addition, you may change the said embodiment as follows.
In the above embodiment, the temperature range of the lubricating oil temperature is estimated based on the coolant temperature at the time of starting the engine when a predetermined operation time has elapsed from the time of starting, and the same waiting time as the estimated temperature range has elapsed. The abnormality detection of the oil temperature sensor 54 was executed by comparing the actual lubricating oil temperature at the time. In addition to this, in detecting an abnormality of the temperature sensor, for example, when the soak time exceeds a threshold, both the cooling water temperature and the lubricating oil temperature are detected, and whether or not those values are substantially equal. An abnormality of the temperature sensor may be detected.

In the above embodiment, when the divergence between the cooling water temperature and the lubricating oil temperature is equal to or less than the lower limit value T ₁ has set the threshold of the soak time to "0". However, the present invention is not limited to this, and other values may be set in setting the soak time threshold based on the parameters when the engine is stopped.

  In the above embodiment, the soak time threshold is set after the engine is started, but the time for setting the soak time threshold is not limited to this, for example, immediately after each parameter is detected when the engine is stopped. Good.

  In the above embodiment, the present invention is embodied in a temperature sensor abnormality detection device that detects an abnormality of the oil temperature sensor 54 after the engine is started. Not only this, but when detecting a temperature sensor abnormality by setting a soak time threshold when the engine is stopped, for example, when the time of the soak timer exceeds the threshold during engine stop, Using an electronic control unit equipped with a wake-up function to acquire the detection value from the sensor, the engine stop is detected such that an abnormality is detected based on whether or not the detection value detected by the temperature sensor is substantially equal during the engine stop. The present invention may be embodied in a temperature sensor abnormality detection device that performs temperature sensor abnormality detection.

  In the above embodiment, the abnormality detection of the oil temperature sensor 54 is performed based on the coolant temperature detected by the water temperature sensor 53. Not limited to this, the abnormality detection of the water temperature sensor 53 may be executed based on the lubricating oil temperature detected by the oil temperature sensor 54.

  In the above embodiment, the determination unit and the threshold setting unit are embodied by one electronic control device 50. However, the present invention is not limited to this, and these may be embodied by a plurality of electronic control devices.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the internal combustion engine to which embodiment of the abnormality detection apparatus of the temperature sensor concerning this invention is applied, and its periphery structure. The graph which shows an example of the data which linked | related the parameter and threshold value in 1st Embodiment. The flowchart for demonstrating the control routine of the abnormality detection process of a temperature sensor. The graph which shows an example of the data which linked | related the parameter and threshold value in 2nd Embodiment.

Explanation of symbols

T 1 _... lower limit, 10 ... engine, 11 ... cylinder block, 12 ... cylinder, 13 ... piston, 14 ... connecting rod, 15 ... crankshaft, 16 ... combustion chamber, 17 ... injector 18 ... spark plug, 19 ... Water jacket, 20 ... intake passage, 21 ... exhaust passage, 22 ... intake valve, 23 ... exhaust valve, 31 ... throttle valve, 32 ... actuator, 40 ... lubrication system, 41 ... oil pan, 42 ... lubricating oil supply device, 50 DESCRIPTION OF SYMBOLS Electronic control unit 50a ... Soak timer 51 ... Air flow meter 52 ... Throttle sensor 53 ... Water temperature sensor 54 ... Oil temperature sensor 55 ... Outside temperature sensor 56 ... Ignition switch

Claims (4)

An oil temperature sensor for detecting the lubricating oil temperature when a stop period, which is a time from when the internal combustion engine is stopped to when the internal combustion engine is exceeded, exceeds a threshold value for obtaining a correlation between the lubricating oil temperature and the cooling water temperature in the internal combustion engine. The temperature sensor abnormality detection device detects whether there is an abnormality in the temperature sensor by determining whether or not a deviation width between the detected value of the cooling water temperature and the detection value of the water temperature sensor that detects the cooling water temperature is a reference value. And
The threshold value is set based on the deviation width at the stop so that the threshold is shortened as the deviation width between the lubricating oil temperature and the cooling water temperature at the stop is smaller. Anomaly detection device.   The temperature sensor abnormality detection device according to claim 1, wherein the threshold is set for each outside air temperature of the internal combustion engine.   3. The temperature sensor abnormality detection device according to claim 1, wherein the threshold value is set to “0” when the deviation width at the time of the stop is a value indicating a correlation between the lubricating oil temperature and the cooling water temperature. .   Using the detected value of the water temperature sensor at the start of the internal combustion engine, the estimated value of the lubricating oil temperature when a predetermined operation time has elapsed since the start is calculated, and the predetermined operation time has elapsed since the start Any one of Claims 1-3 which detect the presence or absence of abnormality of the said oil temperature sensor by determining whether the deviation width of the detected value of the said oil temperature sensor and the said estimated value is a reference value. An abnormality detection device for a temperature sensor according to claim 1.

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