阅读说明：本技术 内燃机的诊断装置 (Diagnostic device for internal combustion engine ) 是由 长田英树 于 2020-03-13 设计创作，主要内容包括：一种内燃机(1)的诊断装置(100),内燃机(1)包括供窜漏气流动的窜漏气通道(10),诊断装置(100)包括：检测窜漏气通道(10)内的温度的温度传感器(20)；以及基于温度传感器(20)的检测值来检测内燃机(1)的异常的异常检测部(30)。(A diagnostic device (100) of an internal combustion engine (1), the internal combustion engine (1) including a blowby gas passage (10) through which blowby gas flows, the diagnostic device (100) comprising: a temperature sensor (20) that detects the temperature in the blowby gas passage (10); and an abnormality detection unit (30) that detects an abnormality in the internal combustion engine (1) on the basis of the detection value of the temperature sensor (20).)

1. A diagnostic device for an internal combustion engine, wherein,

the internal combustion engine includes a blowby gas passage through which blowby gas flows,

the diagnostic device includes:

a temperature sensor that detects a temperature within the blowby gas passage; and

an abnormality detection unit that detects an abnormality of the internal combustion engine based on a detection value of the temperature sensor.

2. The diagnostic apparatus for an internal combustion engine according to claim 1,

the abnormality detection section compares a detection value of the temperature sensor with a threshold value to detect an abnormality,

the threshold value is corrected based on at least one of the atmospheric temperature, the temperature of the engine oil, and the temperature of the engine cooling water.

3. The diagnostic apparatus of an internal combustion engine according to claim 2,

the abnormality detection unit corrects the threshold value to a higher value as at least one of an atmospheric temperature, a temperature of engine oil, and a temperature of engine cooling water is higher.

4. The diagnostic device for an internal combustion engine according to any one of claims 1 to 3, wherein,

the internal combustion engine further includes an oil separating member provided to the blowby gas passage for separating oil from the blowby gas,

the temperature sensor is located in a blow-by gas passage on a downstream side of the oil separating member.

5. The diagnostic device for an internal combustion engine according to any one of claims 1 to 4,

the downstream-side end portion of the blowby gas passage is open to the atmosphere,

the temperature sensor is located at a downstream side end portion of the blowby gas passage.

Technical Field

The present disclosure relates to a diagnostic device for an internal combustion engine.

Background

In an internal combustion engine, a blowby gas processing device is known which discharges blowby gas leaking into a crankcase from a clearance between a piston and a cylinder to the atmosphere or returns the blowby gas to an intake passage.

Documents of the prior art

Patent document

Patent document 1: japanese Kokai publication Sho 61-5309

Disclosure of Invention

Technical problem to be solved by the invention

In an internal combustion engine, for example, a piston ring attached to a piston is worn, and thus an abnormality such as an increase in blow-by gas may occur. Such an abnormality is a cause of a failure of the internal combustion engine caused by an increase in the amount of oil contained in the blow-by gas, and therefore needs to be detected promptly.

The present disclosure provides a diagnostic device capable of detecting an abnormality of an internal combustion engine.

Means for solving the problems

According to an aspect of the present disclosure, there is provided a diagnostic device of an internal combustion engine including a blowby gas passage through which blowby gas flows, the diagnostic device including: a temperature sensor that detects a temperature within the blowby gas passage; and an abnormality detection unit that detects an abnormality of the internal combustion engine based on a detection value of the temperature sensor.

The abnormality detection unit may detect an abnormality by comparing a detection value of the temperature sensor with a threshold value, and may correct the threshold value based on at least one of an atmospheric temperature, a temperature of engine oil, and a temperature of engine cooling water.

The abnormality detection unit may correct the threshold value to a higher value as at least one of an atmospheric temperature, a temperature of engine oil, and a temperature of engine cooling water is higher.

The internal combustion engine may further include an oil separating member provided in the blowby gas passage and separating the oil from the blowby gas, and the temperature sensor may be located in the blowby gas passage on a downstream side of the oil separating member.

Further, a downstream end portion of the blow-by gas passage may be open to the atmosphere, and the temperature sensor may be located at the downstream end portion of the blow-by gas passage.

Effects of the invention

According to the diagnostic device of the present disclosure, it is possible to detect an abnormality of the internal combustion engine based on the temperature in the blowby gas passage.

Drawings

Fig. 1 is a schematic configuration diagram of an internal combustion engine.

Fig. 2 is a graph showing the temperature in the blowby gas passage and its threshold value.

Fig. 3 is a map that defines the relationship between the atmospheric temperature and the correction coefficient corresponding to the atmospheric temperature.

Fig. 4 is a map that defines a relationship between the temperature of the engine oil and a correction coefficient corresponding to the temperature.

Fig. 5 is a diagram showing a control flow of the abnormality detection unit.

Fig. 6 is a schematic configuration diagram of an internal combustion engine according to modification 1.

Fig. 7 is a schematic configuration diagram of an internal combustion engine according to modification 2.

Fig. 8 is a map defining a relationship between the temperature of the engine cooling water and a correction coefficient corresponding to the temperature in modification 2.

Fig. 9 is a diagram showing a control flow of the abnormality detection unit in modification 2.

Fig. 10 is a diagram showing a control flow of the abnormality detection unit in modification 3.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the following embodiments. The respective directions of the upper, lower, left and right sides shown in the drawings are determined for convenience of explanation only.

First, a schematic configuration of the internal combustion engine 1 will be described with reference to fig. 1. In the figure, the open arrows a indicate the flow of intake air, and the grid arrows B indicate the flow of blow-by gas. In addition, black arrows O indicate the flow of the oil separated from the blowby gas.

The internal combustion engine 1 is a multi-cylinder compression ignition type internal combustion engine mounted on a vehicle (not shown), that is, a diesel engine. The vehicle is a large vehicle such as a truck. However, the type, form, use, and the like of the vehicle and the internal combustion engine 1 are not particularly limited, and for example, the vehicle may be a small vehicle such as a passenger car, and the internal combustion engine 1 may be a spark ignition type internal combustion engine, that is, a gasoline engine.

The internal combustion engine 1 includes: an engine body 2; an intake manifold 3 connected to the engine body 2; and an intake pipe 4 connected to an upstream end of the intake manifold 3. The internal combustion engine 1 further includes exhaust system components such as an exhaust pipe (not shown), but the description thereof is omitted here.

In addition, described in detail later, the internal combustion engine 1 of the present embodiment includes a blowby gas passage 10 through which blowby gas flows. In addition, the internal combustion engine 1 includes an oil separating member 11 for separating oil from blow-by gas.

The engine body 2 includes: a cylinder body 5; a crankcase 6 integrally formed at a lower portion of the cylinder block 5; and an oil pan 7 connected to a lower portion of the crankcase 6. In addition, the engine body 2 includes: a cylinder head 8 connected to an upper portion of the cylinder block 5; and a head cover 9 attached to an upper portion of the cylinder head 8.

A plurality of cylinders 5a are provided in the cylinder block 5, and a piston 5b is accommodated in each cylinder 5 a. A crankshaft (not shown) is accommodated in the crankcase 6, and engine oil is accumulated in the oil pan 7. Further, a valve mechanism (not shown) is mounted on the cylinder head 8, and the valve mechanism is covered from above by a head cover 9. Further, an oil passage G for accumulating engine oil is formed in the crankcase 6. Further, a water jacket J through which engine cooling water flows is formed in the cylinder block 5 and the cylinder head 8.

The intake manifold 3 is connected to a cylinder head 8, and distributes and supplies intake air fed from the intake pipe 4 to intake ports of the cylinders 5 a. An air cleaner 4a, a compressor 4b of a turbocharger, and an intercooler 4c are provided in this order from the upstream side in the intake pipe 4.

The blowby gas passage 10 includes in order from the upstream side in the blowby gas flow direction: an in-engine passage 10a passing through the inside of the engine body 2; and a blowby gas pipe 10b exposed to the outside of the engine body 2. As is well known, blowby gas is gas that leaks into the crankcase 6 from a clearance between the cylinder 5a and the piston 5b in the engine body 2. Although not shown, the amount of blow-by gas in the crankcase 6 is limited to a minimum by a plurality of piston rings attached to the piston 5 b.

The in-engine passage 10a communicates with the inside of the head cover 9 through the inside of the cylinder block 5 and the cylinder head 8 from the inside of the crankcase 6.

For example, a resin hose member is used for the blowby gas pipe 10 b. The upstream end of the blowby gas pipe 10b is connected to the upper surface portion of the cylinder head cover 9. On the other hand, the downstream end of the blowby gas pipe 10b is open to the atmosphere at a height position near the lower end of the engine main body 2.

The in-engine passage 10a and the blowby gas pipe 10b communicate via an oil separation chamber 10c provided in an upper portion of the head cover 9. Although not shown, the oil separation chamber 10c has a plurality of baffles, and is configured to separate oil by collision of blow-by gas introduced from the engine interior passage 10a against the baffles. Further, the oil separated from the blowby gas is returned from the oil separation chamber 10c to the crankcase 6 through the engine internal passage 10 a.

The oil separating member 11 is provided outside the engine body 2 on the way of the blowby gas pipe 10 b. The oil separating member 11 incorporates a filter element 11a for separating oil from blow-by gas. However, the type of the oil separating member 11 may be any type, and may be, for example, a centrifugal oil separating member having no filter element.

Further, a return pipe 11b for returning the oil O separated from the blowby gas into the crankcase 6 is connected to the oil separating member 11 of the present embodiment. Further, although not shown, the oil separating member 11 is provided with: a bypass flow path for flow rate adjustment bypassing the filter element 11 a; and an opening/closing valve for opening/closing the bypass flow path.

With the above configuration, as shown by arrow B in fig. 1, during operation of the internal combustion engine 1, blowby gas in the crankcase 6 flows through the engine internal passage 10a and the blowby gas pipe 10B in this order, and is released into the atmosphere. At this time, the oil contained in the blow-by gas is separated from the blow-by gas by the oil separation chamber 10c and the oil separation member 11.

As shown by an arrow O in fig. 1, the oil separated in the oil separation chamber 10c is returned to the crankcase 6 through the engine internal passage 10 a. The oil separated in the oil separator 11 is returned to the crankcase 6 through a return pipe 11 b.

Next, the diagnostic device 100 of the internal combustion engine 1 will be described in detail.

In the internal combustion engine 1, for example, an abnormality may occur in which blow-by gas in the crankcase 6 increases due to wear or damage of piston rings.

In the case where the blowby gas increases, the pressure in the crankcase 6 becomes high. Therefore, the oil discharged from the oil separation chamber 10c is difficult to return into the crankcase 6 through the engine internal passage 10a, and the oil may flow back in the oil separation chamber 10c and flow into the blowby gas pipe 10b together with the blowby gas. Therefore, the blowby gas containing a large amount of oil flows into the oil separating member 11, and the blowby gas on the downstream side of the oil separating member 11 also contains a large amount of oil. As a result, a larger amount of oil than in a normal state may be released into the atmosphere.

In the oil separating member 11, for example, an opening/closing valve of the bypass passage may not be closed, and a connection passage to the return pipe 11b may be closed. In this case, a larger amount of oil than in a normal state may be discharged to the atmosphere.

In addition, when the blowby gas increases in the crankcase 6, dilution (dilution) of the engine oil due to the blowby gas is likely to occur. Dilution becomes a cause of malfunction of the internal combustion engine 1.

In this regard, the inventors of the present application newly found that: when the abnormality of the internal combustion engine 1 as described above occurs, the temperature in the blowby gas pipe 10b (hereinafter, the pipe internal temperature) tends to increase due to the influence of heat of the oil contained in the blowby gas. That is, the temperature of the oil contained in the blowby gas is higher than the temperature of the blowby gas itself. Therefore, in a normal state, the blowby gas containing almost no oil flows through the blowby gas pipe 10b, and the temperature in the pipe becomes low, and in an abnormal state, the blowby gas containing much oil flows through the blowby gas pipe 10b, and the temperature in the pipe becomes high.

Therefore, the diagnostic device 100 of the present embodiment includes: a temperature sensor 20 that detects the temperature inside the tube; and an abnormality detection unit 30 that detects an abnormality of the internal combustion engine 1 based on a detection value of the temperature sensor 20 (hereinafter, a detected pipe internal temperature).

Specifically, the temperature sensor 20 is attached to the blowby gas pipe 10 b. Although not shown, the abnormality detection unit 30 is configured by an Electronic Control Unit (ECU) of the vehicle, a controller, or the like, and includes a CPU, a ROM, a RAM, an input/output interface, and the like. The temperature sensor 20 is electrically connected to the abnormality detection unit 30.

As shown in FIG. 2, the abnormality detector 30 detects the temperature T in the pipe and a predetermined normal threshold value T_LComparing to detect the temperature T in the tube as a normal threshold value T_LHereinafter, the internal combustion engine 1 is detected as normal. The abnormality detector 30 detects the temperature T in the pipe and a predetermined abnormality threshold T_HComparing the temperature T in the detection pipe with an abnormal threshold value T_HIn the above case, the internal combustion engine 1 is detected as abnormal. Anomaly threshold T_HCorresponding to the threshold value described in the patent protection scope, is set to be higher than the normal threshold value T_LHigher temperature (T)_H＞T_L). When an abnormality of the internal combustion engine 1 is detected, the abnormality detection unit 30 turns on a warning lamp (not shown) to notify the driver of the abnormality.

Therefore, if the diagnostic device 100 of the present embodiment is used, it is possible to detect an abnormality of the internal combustion engine 1 based on the temperature in the blowby gas passage 10.

In addition, the abnormality detector 30 of the present embodiment detects that the in-pipe temperature T is less than the abnormality threshold T_HAnd is higher than normal threshold T_LIn the high state, the normality and abnormality of the internal combustion engine 1 are not detected and remain. This enables reliable detection in consideration of variations in the temperature T in the detection pipe.

As shown in fig. 1, the temperature sensor 20 of the present embodiment is located in the blowby gas pipe 10b on the downstream side of the oil separating member 11. Although not shown, if the temperature sensor 20 is located in the blow-by gas pipe 10b on the upstream side of the oil separating member 11, the blow-by gas before oil separation causes the temperature in the detection pipe to be high even in a normal state. Further, for example, even in the case where the organic oil separating member 11 is not provided in the blowby gas pipe 10b, the temperature in the detection pipe may be high similarly. In these cases, the difference between the temperature T in the detection pipe in the normal state and the temperature T in the detection pipe in the abnormal state is small, and the detection accuracy may be lowered.

In contrast, the temperature sensor 20 of the present embodiment is located in the blowby gas pipe 10b on the downstream side of the oil separating member 11, and detects the pipe temperature in which the blowby gas after the oil separation flows. Therefore, the detection pipe internal temperature T can be made low in the normal state, and can be made high in the abnormal state. As a result, the temperature difference between the normal time and the abnormal time becomes significant, and the detection accuracy can be improved.

The temperature sensor 20 of the present embodiment is located at the downstream end of the blowby gas pipe 10b that is open to the atmosphere. In this way, the temperature sensor 20 is easily affected by the atmospheric temperature during normal operation, and therefore the detection pipe internal temperature T tends to become lower. In contrast, in the abnormal state, the temperature T in the detection pipe becomes high due to the influence of heat of the oil contained in the blow-by gas. As a result, the temperature difference between the normal time and the abnormal time becomes more significant, and the detection accuracy of the normal and abnormal times can be improved.

On the other hand, the higher the atmospheric temperature and the temperature of the engine oil (hereinafter, oil temperature), the higher the value of the detection pipe internal temperature T. Therefore, assume the above-mentioned normal threshold value T_LAnd an abnormal threshold value T_HIf the constant value is not changed, the normal state and the abnormal state may be erroneously detected due to the atmospheric temperature and the oil temperature.

Therefore, the abnormality detection unit 30 of the present embodiment corrects the normal threshold value T based on the atmospheric temperature and the oil temperature_LAnd an abnormal threshold value T_H。

Specifically, the diagnostic device 100 of the present embodiment further includes: an atmospheric temperature sensor 40 that detects an atmospheric temperature; and an oil temperature sensor 50 that detects an oil temperature.

An air flow meter capable of detecting an intake air flow rate and an atmospheric temperature is used for the atmospheric temperature sensor 40. The atmospheric temperature sensor 40 is attached to the intake pipe 4 on the upstream side of the compressor 4b and immediately downstream of the air cleaner 4a in the intake flow direction. The oil temperature sensor 50 is mounted to the oil passage G of the crankcase 6. The atmospheric temperature sensor 40 and the oil temperature sensor 50 are electrically connected to the abnormality detection unit 30.

As shown in fig. 3, the abnormality detector 30 includes an atmospheric temperature map M1, in which an atmospheric temperature map M1 defines a relationship between a detection value (hereinafter, detected atmospheric temperature) TA of the atmospheric temperature sensor 40 and a correction coefficient (hereinafter, atmospheric temperature correction coefficient) KA corresponding to the detected atmospheric temperature TA.

In the atmospheric temperature map M1, the relationship between the detected atmospheric temperature TA and the atmospheric temperature correction coefficient KA is set so that the atmospheric temperature correction coefficient KA becomes a larger value as the detected atmospheric temperature TA becomes higher. In addition, the atmospheric temperature map M1 stores a reference atmospheric temperature T that is equal to a predetermined reference atmospheric temperature_A0(e.g., 25 ℃) corresponding reference atmospheric temperature correction coefficient K_A0(K_A0＝1)。

In the example of the figure, the reference atmospheric temperature TA₀Low measured atmospheric temperature TAa (TAa < TA)₀) Correspondingly, a correction coefficient KA of the atmospheric temperature to the reference value is obtained₀Small correction coefficient of atmospheric temperature KAa (KAa < KA)₀). And further, the reference atmospheric temperature TA₀High detected atmospheric temperature TAb (TAb > TA)₀) Correspondingly, a correction coefficient KA of the atmospheric temperature to the reference value is obtained₀Large atmospheric temperature correction coefficient KAb (KAb > KA)₀)。

As shown in fig. 4, the abnormality detection unit 30 includes an oil temperature map M2, in which an oil temperature map M2 defines a relationship between the detection value (hereinafter, detected oil temperature) TO of the oil temperature sensor 50 and a correction coefficient (hereinafter, oil temperature correction coefficient) KO corresponding TO the detected oil temperature TO.

In the oil temperature map M2, the relationship between the detected oil temperature TO and the oil temperature correction coefficient KO is set such that the higher the detected oil temperature TO, the larger the oil temperature correction coefficient KO becomes. In addition, the oil temperature map M2 stores a reference oil temperature TO that is predetermined₀(e.g., 90 deg.C.) corresponding to reference oil temperature calibrationPositive coefficient KO₀(KO₀＝1)。

In the example of the figure, the reference oil temperature TO is compared with₀Low detected oil temperature TOa (TOa < TO)₀) Correspondingly, a correction coefficient KO of the reference oil temperature is obtained₀Small oil temperature correction factor KOa (KOa < KO)₀). And the reference oil temperature TO₀High detected oil temperature TOb (TOb > TO₀) Correspondingly, a correction coefficient KO of the reference oil temperature is obtained₀Large oil temperature correction factor KOb (KOb > KO)₀)。

The abnormality detection unit 30 compares the reference normality threshold T before correction with the reference normality threshold T before correction_L0Multiplying the atmospheric temperature correction coefficient KA and the oil temperature correction coefficient KO to calculate a corrected normal threshold value T_L(T_L＝T_L0XKA XKO). The abnormality detection unit 30 compares the reference abnormality threshold T before correction with the reference abnormality threshold T before correction_H0Multiplying the atmospheric temperature correction coefficient KA and the oil temperature correction coefficient KO to calculate a corrected abnormal threshold value T_H(T_H＝T_H0×KA×KO)。

Thus, the higher the detected atmospheric temperature TA and the detected oil temperature TO are, the higher the normal threshold value T is_LAnd an abnormal threshold value T_HThe higher the correction is, the lower the detected atmospheric temperature TA and the detected oil temperature TO are, the lower the correction is. As a result, erroneous detection due to the atmospheric temperature and the oil temperature can be suppressed.

Next, a control routine of the abnormality detection unit 30 will be described with reference to fig. 5.

The abnormality detection unit 30 repeatedly executes the control flow of fig. 5 at predetermined calculation intervals (e.g., 10ms) during a predetermined operating state (e.g., an idling operating state) of the internal combustion engine 1. This makes it possible to detect the in-pipe temperature and the oil temperature that vary depending on the operating state of the internal combustion engine 1 under certain conditions.

In step S101, a detected pipe internal temperature T, a detected atmospheric temperature TA, and a detected oil temperature TO are acquired. In step S102, a reference normal threshold T is acquired_L0And a reference anomaly threshold value T_H0。

In step S103, the atmospheric temperature correction coefficient KA corresponding to the detected atmospheric temperature TA is acquired by referring to the atmospheric temperature map M1.

In step S104, the oil temperature correction coefficient KO corresponding TO the detected oil temperature TO is acquired by referring TO the oil temperature map M2.

In step S105, the normal threshold T is set by reference_L0Multiplying the atmospheric temperature correction coefficient KA and the oil temperature correction coefficient KO to calculate a corrected normal threshold value T_L(T_L＝T_L0×KA×KO)。

In step S106, the reference abnormal threshold T is set_H0Multiplying the atmospheric temperature correction coefficient KA and the oil temperature correction coefficient KO to calculate a corrected abnormal threshold value T_H(T_H＝T_H0×KA×KO)。

In step S107, it is determined whether or not the detected pipe internal temperature T acquired in step S101 is an abnormal threshold value T_HAbove (T ≧ T_H). In step S107, it is determined that the detected pipe internal temperature T is an abnormal threshold T_HAbove (T ≧ T_H) If yes, the process proceeds to step S108, where it is detected that the internal combustion engine 1 is abnormal. Then, the process proceeds to step S109 to turn on the warning lamp, and the process returns.

On the other hand, in step S107, it is determined that the detection pipe internal temperature T is not the abnormal threshold T_HAbove (T ≧ T_H) If so (NO), the process proceeds to step S110, where it is determined whether or not the detected temperature T in the pipe is a normal threshold value T_LThe following (T ≦ T_L)。

In step S110, it is determined that the detected pipe internal temperature T is a normal threshold value T_LThe following (T ≦ T_L) If yes, the process proceeds to step S111, where the engine 1 is detected as normal, and the process returns.

On the other hand, in step S110, it is determined that the detection pipe internal temperature T is not the normal threshold T_LThe following (T ≦ T_L) When the detection result is positive (negative), the detection result is returned to the normal state.

The above-described embodiment can employ the following modifications or combinations thereof. In the following description, the same reference numerals are used for the same components as those of the above-described embodiment, and detailed description thereof will be omitted.

(modification 1)

The blowby gas may not be discharged from the blowby gas pipe 10b to the atmosphere, but may be returned to the intake pipe 4. Specifically, as shown in fig. 6, the downstream end of the blowby gas pipe 10b of modification 1 is connected to the intake pipe 4 located between the atmospheric temperature sensor 40 and the compressor 4 b.

(modification 2)

At a normal threshold T_LAnd an abnormal threshold value T_HThe correction of (2) may be performed using parameters other than the atmospheric temperature and the oil temperature.

For example, as shown in fig. 7 to 9, in modification 2, the normal threshold T is set to be the normal threshold T_LAnd an abnormal threshold value T_HIn the correction of (2), the temperature of the engine cooling water (hereinafter, water temperature) is used instead of the oil temperature. Since the engine cooling water is only a temperature lower than the oil temperature by a certain temperature (for example, 10 ℃), and has a correlation with the oil temperature, the engine cooling water can be used as the correction threshold value T similarly to the oil temperature_L、T_HThe parameter (c) of (c).

Specifically, as shown in fig. 7, in modification 2, the oil temperature sensor 50 is omitted, and instead, a water temperature sensor 60 that is attached to the water jacket J and detects the water temperature is used. The abnormality detector 30 of modification 2 includes a water temperature map M3 instead of the oil temperature map M2. As shown in fig. 8, the water temperature map M3 replaces the detected oil temperature TO with the detected value (hereinafter, detected water temperature) TW of the water temperature sensor 60 and replaces the oil temperature correction coefficient KO with the correction coefficient (hereinafter, water temperature correction coefficient) KW corresponding TO the detected water temperature TW with respect TO the oil temperature map M2 shown in fig. 4.

As shown in fig. 9, in the control flow of modification 2, steps S101, 104 to 106 shown in fig. 5 are replaced with steps S101A, 104A to 106A. In step S101A, the detected pipe internal temperature T, the detected atmospheric temperature TA, and the detected water temperature TW are acquired, and in step S104A, a water temperature correction coefficient KW is acquired. Then, in step S105A and step S106A, a normal threshold T is calculated based on the atmospheric temperature correction coefficient KA and the water temperature correction coefficient KW_LAnd an abnormal threshold value T_H。

(modification 3)

At a normal threshold T_LAnd an abnormal threshold value T_HIn addition to the atmospheric temperature and the oil temperature, other parameters may be used in the correction of (1).

Specifically, as shown in fig. 10, in the control flow of modification 3, steps S101, 105, and 106 shown in fig. 5 are replaced with steps S101B, 105B, and 106B using the water temperature as a parameter. In addition, step S104B is provided between step S104 and step S105B. In step S101B, the detected pipe internal temperature T, the detected atmospheric temperature TA, the detected oil temperature TO, and the detected water temperature TW are acquired, and in step S104B, a water temperature correction coefficient KW is acquired. Then, in step S105B and step S106B, a normal threshold value T is calculated based on the atmospheric temperature correction coefficient KA, the oil temperature correction coefficient KO, and the water temperature correction coefficient KW_LAnd an abnormal threshold value T_H。

(modification 4)

The normal threshold T may also be corrected based on a parameter (e.g., atmospheric temperature)_LAnd an abnormal threshold value T_H。

(modification 5)

Although not shown, the normal threshold T may not be corrected_LAnd an abnormal threshold value T_H. Specifically, the abnormality detector 30 of the 5 th modification detects the in-pipe temperature T and the reference normality threshold T_L0And a reference anomaly threshold value T_H0The comparison is performed to detect the normality and abnormality of the internal combustion engine.

(modification 6)

May also replace the normal threshold value T_LAnd an abnormal threshold value T_HAnd correcting the temperature T in the detection pipe. Specifically, the abnormality detector 30 of modification 6 divides the detected pipe internal temperature T by the atmospheric temperature correction coefficient KA and the oil temperature correction coefficient KO to calculate a corrected detected pipe internal temperature T '(T' ═ T/(KA × KO)). Then, the corrected temperature T' in the detection pipe is compared with a reference normal threshold value T_L0And a reference anomaly threshold value T_H0The comparison is performed to detect the normality and abnormality of the internal combustion engine.

(modification 7)

The normal threshold value T may be omitted_LAnd an abnormal threshold value T_HNormal threshold value T in_L. In modification 7, it is determined only whether or not the detected pipe internal temperature T is an abnormal threshold value T_HThe above.

(modification 8)

The oil separating member 11 may be omitted from the blowby gas pipe 10b if the temperature difference between the detection pipe internal temperature T at the normal time and the detection pipe internal temperature T at the abnormal time is significant.

(modification 9)

If the temperature difference between the detection pipe internal temperature T at the normal time and the detection pipe internal temperature T at the abnormal time is significant, the temperature sensor 20 may not be positioned at the downstream end of the blowby gas pipe 10 b. For example, the temperature sensor 20 of the 9 th modification is attached to the blowby gas pipe 10b located immediately downstream of the oil separating member 11.

The embodiments of the present disclosure have been described in detail, but the embodiments of the present disclosure are not limited to the above embodiments, and all modifications, applications, and equivalents included in the idea of the present disclosure defined in the claims are included in the present disclosure. Therefore, the present disclosure should not be construed as limited to , and can be applied to any other technique within the scope of the idea of the present disclosure.

The present application is based on the japanese patent application published on 3/15/2019 (japanese application 2019-048605), the contents of which are incorporated herein by reference.

Industrial applicability

According to the diagnostic device of the present disclosure, it is possible to detect an abnormality of the internal combustion engine based on the temperature in the blowby gas passage.

Description of the reference numerals

1 internal combustion engine

2 Engine body

3 air intake manifold

4 air inlet pipe

5 Cylinder body

6 crankcase

7 oil pan

8 cylinder cover

9 cylinder head cover

10 blowby gas channel

10a in-engine passage

10b blowby gas pipe

10c machine oil separating chamber

11 oil separating part

20 temperature sensor

30 abnormality detection unit

40 atmosphere temperature sensor

50 oil temperature sensor

100 diagnostic device

A intake air

Blow-by gas of B

Engine oil with O separated from blow-by gas

T_LNormal threshold value

T_HAbnormal threshold (threshold)