阅读说明：本技术 内燃机的故障判定装置 (Failure determination device for internal combustion engine ) 是由 关口畅 木本隆史 广田拓 石川弘毅 于 2021-02-09 设计创作，主要内容包括：本发明提供一种内燃机的故障判定装置,能够适当且迅速地判定通气配管等配管的故障。该故障判定装置判定在具备增压机(2)的内燃机(1)中连接在曲轴箱(3)与进气通路(4)中的增压机(2)的上游侧之间的通气配管(7)的故障,通气配管(7)由具有内管(8)及外管(9)的双重管构成,通气配管(7)的内管(8)与外管(9)之间的密闭空间(10)和进气通路(4)中的增压机(2)的下游侧之间通过连通路(15)而连通,当检测到的通气外管表压PDGA为根据检测到的进气表压PBGA而设定的判定阈值PDGATH以上时,判定为通气配管(7)发生了故障。(The invention provides a failure determination device for an internal combustion engine, which can appropriately and rapidly determine the failure of a pipe such as a ventilation pipe. The failure determination device determines a failure of a ventilation pipe (7) connected between a crankcase (3) and the upstream side of a supercharger (2) in an intake passage (4) in an internal combustion engine (1) provided with the supercharger (2), wherein the ventilation pipe (7) is composed of a double pipe having an inner pipe (8) and an outer pipe (9), a sealed space (10) between the inner pipe (8) and the outer pipe (9) of the ventilation pipe (7) and the downstream side of the supercharger (2) in the intake passage (4) are communicated through a communication passage (15), and when a detected ventilation outer pipe gauge pressure PDGA is equal to or more than a determination threshold PDGATH set according to a detected intake gauge pressure PBGA, the ventilation pipe (7) is determined to have a failure.)

1. A failure determination device for an internal combustion engine, which determines a failure of a breather pipe that is connected between a crankcase and an upstream side of a supercharger in an intake passage in the internal combustion engine provided with the supercharger and that communicates the crankcase with the intake passage, the failure determination device being characterized in that,

the breather pipe is composed of a double pipe having an inner pipe that communicates the crankcase with the intake passage, and an outer pipe that is disposed at a predetermined interval on the outer peripheral side of the inner pipe and forms a closed space with the inner pipe,

the failure determination device includes:

a communication passage that communicates between the sealed space of the ventilation pipe and a downstream side of the turbocharger in the intake passage;

a ventilation outer tube pressure detection means for detecting the pressure in the sealed space of the ventilation pipe as a ventilation outer tube pressure;

an intake pressure detection unit that detects a pressure on a downstream side of the supercharger in the intake passage as an intake pressure;

a determination threshold value setting unit that sets a determination threshold value for determining whether or not a failure has occurred, based on the detected intake pressure; and

and a failure determination unit that determines that the ventilation pipe has failed when the detected ventilation outer pipe pressure is equal to or higher than the determination threshold.

2. The failure determination device of an internal combustion engine according to claim 1,

the failure determination means performs failure determination of the ventilation pipe when the detected intake pressure is equal to or lower than a predetermined value.

3. The failure determination device of an internal combustion engine according to claim 1 or 2,

the failure determination device further includes an atmospheric pressure detection means for detecting atmospheric pressure,

the determination threshold setting unit sets the determination threshold based on a relationship between the detected intake pressure and the detected atmospheric pressure.

4. The failure determination device of an internal combustion engine according to claim 3,

the determination threshold value setting means sets the determination threshold value as a determination threshold value for gauge pressure based on an intake air gauge pressure obtained by subtracting the detected atmospheric pressure from the detected intake air pressure,

the failure determination means determines that the ventilation pipe has failed when a ventilation outer tube gauge pressure obtained by subtracting the detected atmospheric pressure from the detected ventilation outer tube pressure is equal to or greater than the gauge pressure determination threshold value.

5. The failure determination device of an internal combustion engine according to claim 1,

the communication passage communicates between the sealed space of the ventilation pipe and a downstream side of a throttle valve in the intake passage,

the intake pressure detecting unit detects a pressure on a downstream side of the throttle valve in the intake passage as an intake pressure.

6. The failure determination device of an internal combustion engine according to claim 5,

a check valve is provided at a connection portion between the communication passage and the intake passage on the downstream side of the throttle valve.

7. A failure determination device for an internal combustion engine, which determines a failure of a predetermined pipe provided in the internal combustion engine and communicating a 1 st portion and a 2 nd portion to be communicated with each other,

the piping is composed of a double pipe having an inner pipe communicating the 1 st portion and the 2 nd portion, and an outer pipe disposed outside the inner pipe with a predetermined space therebetween and forming a sealed space with the inner pipe,

the failure determination device includes:

a communication passage that communicates the sealed space of the pipe with a downstream side of a throttle valve in an intake passage;

an outer tube pressure detection means for detecting a pressure in the sealed space of the pipe as an outer tube pressure;

an intake pressure detection unit that detects a pressure on a downstream side of the throttle valve in the intake passage as an intake pressure;

a determination threshold value setting unit that sets a determination threshold value for determining whether or not a failure has occurred, based on the detected intake pressure; and

and a failure determination unit that determines that the pipe has failed when the detected outer pipe pressure is equal to or greater than the determination threshold.

8. The failure determination device of an internal combustion engine according to any one of claims 1 to 7,

the communication passage has a passage area smaller than a predetermined size for determining a failure.

Technical Field

The present invention relates to a failure determination device for an internal combustion engine, which determines a failure caused by, for example, a dropping or a breakage of a breather pipe or the like connected between a crankcase of the internal combustion engine and an upstream side of a compressor in an intake passage.

Background

In general, an internal combustion engine is provided with a variety of pipes. For example, a PCV pipe and a breather pipe are provided that communicate a crankcase of the internal combustion engine with the exhaust system and allow blowby gas that leaks from the combustion chamber into the crankcase to flow into the intake system.

Fig. 11 schematically shows an engine provided with a PCV pipe and a ventilation pipe and provided with a supercharger. As shown in the drawing, the PCV pipe 31 is connected between the crankcase 33 and the intake manifold 34 of the engine 32. When the engine 32 is running, negative pressure is generated in the intake manifold 34, whereby the PCV valve 35 with a check valve is opened, and blowby gas in the crankcase 33 is drawn to the intake manifold 34 side, and this drawn blowby gas is burned in each cylinder 32 a.

On the other hand, the breather pipe 41 is connected between the crankcase 33 and the upstream side (left side in fig. 11) of the compressor 43a of the supercharger 43 in the intake passage 42. Further, in the intake passage 42, an air cleaner 44 and an air flow meter 45 are disposed at a position on the upstream side of a connection portion with the breather pipe 41, and a throttle valve 46 is disposed between the compressor 43a and the intake manifold 34. In the breather pipe 41 described above, air flows from the intake passage 42 side to the crankcase 33 side during natural intake of the engine 32, while blowby gas in the crankcase 33 flows from the crankcase 33 side to the intake passage 42 side during supercharging due to suction by the negative pressure of the compressor 43.

The breather pipe 41 is required to be connected in an airtight state between the crankcase 33 and the intake passage 42 by firmly and appropriately attaching both end portions thereof to the crankcase 33 and the intake passage 42. However, there is a case where a failure occurs in the breather pipe 41 due to the breather pipe 41 coming off the crankcase 33 or the intake passage 42 or a hole being formed in the breather pipe 41, and as a device for determining such a failure, for example, a failure determination device disclosed in patent document 1 is known.

In this failure determination device, the air-fuel ratio of the mixture gas is detected by an air-fuel ratio sensor provided in the exhaust passage, and a deviation from an appropriate fuel injection amount, that is, a fuel correction amount is calculated. When the sum of the fuel correction amount during supercharging and the fuel correction amount during non-supercharging is equal to or greater than a predetermined determination value, it is determined that a failure has occurred in the breather pipe 41 or the like.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-137547

Disclosure of Invention

Problems to be solved by the invention

In the above-described failure determination device, when the ventilation pipe 41 has failed, the air-fuel ratio changes due to inflow of the external air into the intake passage or outflow of the intake air from the intake passage to the outside, and the failure of the ventilation pipe 41 is determined based on the fuel correction amount corresponding to the change. However, when the degree of the failure is relatively small and the inflow and outflow of air into and out of the ventilation pipe 41 is small, the failure of the ventilation pipe 41 may not be appropriately determined. In addition, in the above determination device, since the failure of the breather pipe 41 is determined using the sum of the fuel correction amount at the time of supercharging and the fuel correction amount at the time of non-supercharging, there is a problem as follows: when the ventilation pipe 41 has failed during either the supercharging or the non-supercharging, the failure determination cannot be made until the other of the supercharging and the non-supercharging is achieved.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a failure determination device for an internal combustion engine, which can appropriately and quickly determine a failure of a pipe such as a breather pipe.

Means for solving the problems

In order to achieve the above object, the invention of claim 1 is a failure determination device for an internal combustion engine, which determines a failure of a breather pipe 7, the breather pipe 7 being connected between a crankcase 3 and an upstream side of a supercharger in an intake passage 4 in the internal combustion engine 1 including the supercharger 2 and communicating the crankcase and the intake passage, the failure determination device for an internal combustion engine being characterized in that the breather pipe is composed of a double pipe having an inner pipe 8 communicating the crankcase and the intake passage, and an outer pipe 9 disposed at an outer peripheral side of the inner pipe with a predetermined interval therebetween and forming a sealed space 10 with the inner pipe,

the failure determination device includes: a communication passage 15 that communicates between the sealed space of the ventilation pipe and the downstream side of the supercharger in the intake passage; a ventilation outer tube pressure detection means (an outer tube pressure sensor 22 in the embodiment (the same applies hereinafter) that detects the pressure of the sealed space of the ventilation pipe as a ventilation outer tube pressure PDA; an intake pressure detection means (intake pressure sensor 21) that detects a pressure on the downstream side of the supercharger in the intake passage as an intake pressure PBA; a determination threshold value setting unit (ECU 20) that sets a determination threshold value for determining whether or not a failure has occurred, based on the detected intake air pressure; and a failure determination unit that determines that the ventilation pipe has failed when the detected ventilation outer pipe pressure is equal to or greater than a determination threshold value.

According to this configuration, a breather pipe is connected between the crankcase and the upstream side of the supercharger in the intake passage, and the crankcase and the intake passage are communicated with each other. Through this breather pipe, when the internal combustion engine is in an operating state based on natural intake air, a part of the intake air flows from the intake passage side to the crankcase side, while when the internal combustion engine is in a supercharging operating state, blowby gas in the crankcase flows from the crankcase side to the intake passage side due to negative pressure generated by the compressor of the supercharger. The breather pipe is composed of a double pipe having an inner pipe that communicates the crankcase with the intake passage and an outer pipe disposed at the outer peripheral side of the inner pipe with a predetermined gap therebetween, and a sealed space is formed between the inner pipe and the outer pipe. Further, the communication passage communicates the sealed space of the ventilation pipe with the downstream side of the supercharger in the intake passage. The pressure in the sealed space of the ventilation pipe is detected as the ventilation outer tube pressure by the ventilation outer tube pressure detection means, and the pressure on the downstream side of the supercharger in the intake passage is detected as the intake pressure by the intake pressure detection means.

As described above, since the closed space of the breather pipe communicates with the downstream side of the turbocharger in the intake passage via the communication passage, the pressure on both ends of the communication passage, that is, the breather outer pipe pressure and the intake air pressure become substantially the same value in the normal state where the breather pipe is appropriately connected between the crankcase and the upstream side of the turbocharger in the intake passage.

In contrast, for example, when the breather pipe falls off the crankcase or the intake passage or a failure occurs due to breakage caused by a puncture, the breather outer tube pressure becomes a value at or near atmospheric pressure. Further, the value of the ventilation outer tube pressure changes depending on the size of the hole caused by the breakage of the ventilation pipe. That is, the larger the size of the hole, the larger the breakage, the closer the outer ventilation tube pressure becomes to the atmospheric pressure, while the smaller the size of the hole, the smaller the breakage, the closer the outer ventilation tube pressure becomes to the intake pressure.

From the above, for example, in a graph in which the intake pressure is plotted on the horizontal axis and the ventilation outer tube pressure is plotted on the vertical axis, when the ventilation pipe is normal, the intake pressure and the ventilation outer tube pressure at the same detection time are plotted on a straight line (hereinafter, referred to as "inclined line" in this column) inclined to the upper right and connecting points at which the intake pressure and the ventilation outer tube pressure are the same value, or around the inclined line. In the above-described graph, when the failure of the ventilation pipe is large and the ventilation outer tube pressure is equal to the atmospheric pressure, the intake air pressure and the ventilation outer tube pressure at the same detection time are plotted on a horizontal straight line (hereinafter, referred to as a "horizontal line" in this column) having the same value as the atmospheric pressure regardless of the values of the ventilation outer tube pressure and the intake air pressure.

In the above graph, when the degree of the failure is smaller than the failure of the breather pipe, the intake pressure and the breather outer tube pressure at the same detection time are plotted as the inclined line in the case where the horizontal line is close to normal. Therefore, as a straight line indicating a threshold value for determining whether or not there is a failure in the ventilation pipe, a straight line (hereinafter, referred to as a "threshold value line" in this column) that is inclined upward to the right through an intersection of the inclined line and the horizontal line can be set. Therefore, by using such a threshold line, a determination threshold value for determining the presence or absence of a failure from the detected intake air pressure can be obtained. When the detected ventilation outer tube pressure is equal to or higher than the determination threshold value, it can be determined that the ventilation pipe is broken. As described above, according to the present invention, the intake air pressure and the ventilation outer tube pressure at the same detection time are used, and the ventilation outer tube pressure is compared with the determination threshold, whereby the failure of the ventilation pipe can be appropriately and quickly determined.

The invention according to claim 2 is the failure determination device for an internal combustion engine according to claim 1, wherein the failure determination means performs failure determination of the ventilation pipe when the detected intake pressure is equal to or lower than a predetermined value (upper limit value UPLIM) (PBGA ≦ UPLIM, step 2: yes).

According to this configuration, since the failure determination of the ventilation pipe is performed when the detected intake air pressure is equal to or lower than the predetermined value, it is possible to effectively prevent the erroneous determination due to the deviation between the detected intake air pressure and the ventilation outer pipe pressure.

The invention of claim 3 is the failure determination device for an internal combustion engine described in claim 1 or 2, further comprising atmospheric pressure detection means (atmospheric pressure sensor 24) for detecting atmospheric pressure, wherein the determination threshold value setting means sets the determination threshold value (threshold value pdatah) based on a relationship between the detected intake pressure PBA and the detected atmospheric pressure PA (intake gage pressure PBGA-PBA).

According to this configuration, since the determination threshold value is set by the determination threshold value setting means based on the relationship between the detected intake pressure and the atmospheric pressure, erroneous determination can be suppressed as compared with the case where the determination threshold value is set based on only the intake pressure.

The invention according to claim 4 is the failure determination device according to claim 3, wherein the determination threshold setting means sets the determination threshold as the determination threshold for gauge pressure (threshold PDGATH) based on an intake air gauge pressure PBGA obtained by subtracting the detected atmospheric pressure PA from the detected intake air pressure PBA, and the failure determination means determines that the ventilation pipe has failed when a ventilation outer pipe gauge pressure PDGA obtained by subtracting the detected atmospheric pressure PA from the detected ventilation outer pipe pressure PDA is equal to or greater than the determination threshold for gauge pressure (PDGA ≧ PDGATH, step 7: YES).

According to this configuration, the determination threshold value is set as the determination threshold value for gauge pressure based on the intake air gauge pressure obtained by subtracting the atmospheric pressure from the detected intake air pressure. Then, when the ventilation outer tube gauge pressure obtained by subtracting the atmospheric pressure from the detected ventilation outer tube pressure is equal to or greater than the determination threshold value for gauge pressure, it is determined that a failure has occurred in the ventilation pipe. As described above, since the failure determination of the ventilation pipe is performed using the determination threshold values for the ventilation outer tube gauge pressure and the gauge pressure, which are pressures based on the atmospheric pressure, at the time of the failure determination of the ventilation pipe, the failure determination of the ventilation pipe can be appropriately performed without being affected by the change in the atmospheric pressure even if the atmospheric pressure changes.

The invention according to claim 5 is a failure determination device for an internal combustion engine 1, which determines a failure of a predetermined pipe (breather pipe 7) that is provided in the internal combustion engine and that communicates a 1 st portion (crankcase 3) and a 2 nd portion (intake passage 4) that are to communicate with each other, the pipe being formed of a double pipe having an inner pipe 8 that communicates the 1 st portion and the 2 nd portion with each other, and an outer pipe 9 that is disposed outside the inner pipe at a predetermined interval and forms a closed space 10 with the inner pipe, the failure determination device including: a communication passage 15 that communicates the sealed space of the pipe with the downstream side of the throttle valve 14 in the intake passage; an outer tube pressure detection means (outer tube pressure sensor) for detecting the pressure in the sealed space of the piping as an outer tube pressure (ventilation outer tube pressure PDA); an intake pressure detection unit (intake pressure sensor 21) that detects a pressure on a downstream side of the throttle valve in the intake passage as an intake pressure PBA; a determination threshold setting unit (ECU 20) that sets a determination threshold (threshold PDGATH) for determining the presence or absence of a failure, based on the detected intake air pressure; and a failure determination unit (ECU 20, step 7: YES) that determines that the pipe has failed when the detected outer pipe pressure is equal to or greater than a determination threshold (PDGA ≧ PDGATH).

With this configuration, it is determined that a predetermined pipe, which is provided in the internal combustion engine and is the same as or similar to the ventilation pipe according to claim 1, has a failure. The predetermined pipe is constituted of a double pipe having an inner pipe and an outer pipe, as in the ventilation pipe, the inner pipe communicating between the 1 st portion and the 2 nd portion to be communicated with each other, and a closed space is formed between the inner pipe and the outer pipe. Further, the closed space of the pipe is communicated with the downstream side of the throttle valve in the intake passage via the communication passage. The pressure in the sealed space of the pipe is detected as the outer pipe pressure by the outer pipe pressure detecting means, and the pressure on the downstream side of the throttle valve in the intake passage is detected as the intake pressure by the intake pressure detecting means. The above-described piping can be determined that a failure has occurred in the piping when the detected outer pipe pressure is equal to or higher than a determination threshold set in accordance with the intake air pressure by the same action as that of claim 1. As described above, according to the present invention, similarly to the above-described claim 1, by comparing the outer pipe pressure with the determination threshold value using the intake pressure and the outer pipe pressure at the same detection timing, it is possible to appropriately and quickly determine the failure of the pipe.

The invention according to claim 6 is the failure determination device according to claim 1, wherein the communication passage communicates between the sealed space of the ventilation pipe and a downstream side of the throttle valve 14 in the intake passage, and the intake pressure detection means detects a pressure on the downstream side of the throttle valve in the intake passage as the intake pressure.

According to this configuration, the closed space of the ventilation pipe and the downstream side of the throttle valve in the intake passage communicate with each other through the communication passage, and the pressure on the downstream side of the throttle valve in the intake passage is detected as the intake pressure. Thus, the failure of the ventilation pipe can be appropriately and quickly determined using the intake air pressure and the ventilation outer pipe pressure that become negative pressures.

The invention according to claim 7 is the failure determination device according to claim 6, wherein a check valve is provided at a connection portion (the 2 nd connection port 5b) between the communication passage and the intake passage on the downstream side of the throttle valve

According to this configuration, by providing the check valve at the connection portion, it is possible to prevent negative pressure generated on the downstream side of the throttle valve in the intake passage from acting on the communication passage and the seal member of the ventilation pipe. This can suppress the component performance required for the sealing member, and can reduce the cost by using a relatively inexpensive sealing member.

The invention according to claim 8 is the failure determination device according to any one of claims 1 to 7, wherein a passage area of the communication passage is set smaller than a predetermined size at which a failure should be determined.

According to this configuration, since the passage area of the communication passage is set smaller than the predetermined size at which a failure is to be determined, when a hole having a size larger than the predetermined size is formed in the ventilation pipe, the detected outer tube pressure becomes larger than the pressure difference at the normal time. Therefore, the failure of the ventilation pipe can be detected with high accuracy based on the pressure difference.

Drawings

Fig. 1 is a diagram schematically showing an internal combustion engine and various pipes to which a failure determination device according to an embodiment of the present invention is applied.

Fig. 2 is a block diagram showing a failure determination device of an internal combustion engine.

Fig. 3 is an explanatory diagram for explaining a relationship between the intake air pressure and the ventilation outer tube pressure, where (a) shows a normal state in which the ventilation pipe is appropriately connected, and (b) shows a state in which the ventilation pipe is in a failure state.

Fig. 4 is an enlarged view showing a state in which a breakage due to a puncture hole is generated in the vent pipe of fig. 1, where (a) shows a state in which the hole is large, and (b) shows a state in which the hole is small.

Fig. 5 is a diagram for explaining a failure determination map based on the relationship between the intake air pressure and the ventilation outer tube pressure, in which (a) shows a change in ventilation outer tube pressure based on the magnitude of breakage of the ventilation pipe, and (b) shows a failure determination map.

Fig. 6 is an explanatory diagram for explaining a relationship between the intake air pressure and the ventilation outer tube pressure due to a difference in the elevation, (a) shows a case of a flat land with a low elevation, and (b) shows a case of a high land with a high elevation.

Fig. 7 is a diagram showing a malfunction determination map based on the relationship between the intake air gauge pressure and the ventilation outer tube gauge pressure.

Fig. 8 (a) shows a failure determination map in which determination prohibited areas are provided in the failure determination map of fig. 7, and (b) is a diagram for explaining a method of generating the failure determination map of (a).

Fig. 9 is a flowchart showing the failure determination process.

Fig. 10 (a) shows an example of transition of the intake air gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA, and (b) shows a timing chart of the determination execution condition establishment flag F _ JDGOK, the timer value TMSTA of the steady waiting timer, the timer value TMJDGNG of the failure determination required time timer, and the failure determination flag F _ NG, which change in accordance with the transition of (a).

Fig. 11 is a diagram for explaining PCV piping and breather piping that communicate a crankcase and an intake system in a conventional internal combustion engine.

Description of reference numerals:

1 an internal combustion engine;

2, a supercharger;

3a crankcase;

4 an intake passage;

5 an intake manifold;

6 PCV piping;

7 a ventilation pipe;

8, an inner pipe;

9 an outer tube;

10, sealing a space;

12 a compressor;

14 throttle valves;

15 a communication path;

20 ECU (determination threshold setting means and failure determination means);

21 an intake air pressure sensor (intake air pressure detecting means);

22 an outer tube pressure sensor (ventilation outer tube pressure detection unit);

23 water temperature sensors;

a 24-atmosphere pressure sensor (atmosphere pressure detection means);

25 an alarm;

PBA intake pressure;

PBGA (PBGA) intake gauge pressure;

delta PBGA intake gauge pressure change;

the pressure of the PDA ventilation outer pipe;

PDGA ventilation outer tube gauge pressure;

TW water temperature;

PA atmospheric pressure;

line 1 of L1;

line 2 of L2;

line 3 of L3;

l2' 2 nd descent line;

l3' 3 rd descending line;

L1G No. 1 gauge;

L2G No. 2 gauge;

L3G gauge No. 3;

the upper limit line of the 1 st gauge line of the L1 GUP;

the lower limit line of the 3 rd gauge line of the L3 GDW;

f _ JDGOK judges that the execution condition is satisfied;

f _ TMJDGNG fault determination required time setting completion flag;

f _ TMJDGOK normal judgment required time setting completion flag;

f _ NG failure determination flag;

f _ OK normal decision flag;

a timer value of the TMSTA stable wait timer;

an upper limit value of UPLIM intake gage pressure;

TMSTAREF stabilization latency;

a threshold value for PDGATH ventilation outer tube gauge pressure (gauge pressure determination threshold value);

a timer value of a time timer is needed for TMJDGNG fault determination;

the TMJDGOK normally judges the timer value of the required time timer;

TMJDGREF determination takes time.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 schematically shows an internal combustion engine and various pipes to which a failure determination device according to an embodiment of the present invention is applied. The internal combustion engine (hereinafter referred to as "engine") 1 is a gasoline engine mounted on a four-wheeled vehicle (not shown) as a power source, and includes, for example, 4 cylinders (not shown). As shown in fig. 1, the engine 1 includes a supercharger 2, and a PCV pipe 6 and a breather pipe 7 are connected between a crankcase 3 provided at a lower portion of a main body of the engine 1 and an intake passage 4.

In the intake passage 4, an air cleaner 11, a compressor 12 of the supercharger 2, an intercooler 13, and a throttle 14 are provided in this order from the upstream side. The air cleaner 11 purifies the outside air and introduces the purified outside air into the intake passage 4. Further, the compressor 12 rotates integrally with a turbine on the exhaust passage side (not shown) in accordance with the rotation thereof, thereby pressurizing intake air (hereinafter referred to as "intake air") and sending the pressurized intake air to the cylinders of the engine body, and the intercooler 13 cools the intake air whose temperature has been increased by the pressurization. The throttle valve 14 is rotated in conjunction with an accelerator pedal, not shown, to adjust the intake air amount.

Further, an intake manifold 5 is provided on the downstream side of the throttle valve 14 of the intake passage 4. The intake manifold 5 has the same number of branch pipes as the number of cylinders, and distributes intake air to the cylinders.

The PCV pipe 6 is provided to communicate with the crankcase 3 and the intake manifold 5 by connecting the 1 st opening 3a provided at a predetermined position of the crankcase 3 to the 1 st connection port 5a provided at a predetermined position of the intake manifold 5. The PCV pipe 6 is provided with a PCV valve similar to the PCV valve 35 provided in the PCV pipe 31 of fig. 11, which is not shown.

On the other hand, the ventilation pipe 7 is provided to connect the 2 nd opening 3b provided at a predetermined position of the crankcase 3 to the connection port 4a on the upstream side of the compressor 12 of the supercharger 2 in the intake passage 4. More specifically, the breather pipe 7 is composed of a double pipe having a cylindrical inner pipe 8 that connects the 2 nd opening 3b of the crankcase 3 to the connection opening 4a of the intake passage 4, and a cylindrical outer pipe 9 that is disposed at a predetermined interval on the outer peripheral side of the inner pipe 8 and forms a closed space 10 with the inner pipe 8. A spacer member, not shown, is provided between the inner tube 8 and the outer tube 9, and the inner tube 8 and the outer tube 9 are configured to be immovable in the radial direction with respect to each other via the spacer member.

Further, a communication passage 15 communicating with the intake manifold 5 is connected to the ventilation pipe 7. Specifically, the communication passage 15 is provided to connect a connection port 9a provided at a predetermined position on the outer peripheral surface of the outer tube 9 of the ventilation pipe 7 to a 2 nd connection port 5b provided at a predetermined position on the throttle valve 14 of the intake manifold 5, thereby communicating the sealed space 10 of the ventilation pipe 7 with the intake manifold 5.

An intake air pressure sensor 21 (intake air pressure detecting means) for detecting the pressure of intake air (hereinafter referred to as "intake air pressure") PBA in the intake manifold 5 is provided, and an outer tube pressure sensor 22 (ventilation outer tube pressure detecting means) for detecting the pressure of the sealed space between the inner tube 8 and the outer tube 9 (hereinafter referred to as "ventilation outer tube pressure") PDA is provided in the ventilation pipe 7. A water temperature sensor 23 that detects a temperature TW of the cooling water of the engine 1 (hereinafter referred to as "engine water temperature") is provided in the engine body, and an atmospheric pressure sensor 24 that detects an atmospheric pressure PA is provided in the vehicle.

Fig. 2 is a block diagram showing a failure determination device. The ECU 20 shown in the figure is constituted by a microcomputer constituted by an I/O interface, a CPU, a RAM, a ROM (none of which is shown), and the like. The detection signals from the various sensors 21 to 24 are a/D converted and shaped by the I/O interface, respectively, and then input to the CPU. The CPU determines the operating state of the engine 1 based on these input signals, and executes a process of determining a failure of the engine 1, more specifically, a process of determining a failure due to detachment, breakage, or the like of the ventilation pipe 7, in accordance with a program stored in the ROM. Further, when it is determined that there is a failure, a signal indicating the failure is sent from the ECU 20 to the alarm 25, and notified to the driver of the vehicle. In the present embodiment, the ECU 20 constitutes the determination threshold setting means and the failure determination means of the present invention.

Here, the principle of failure determination based on the relationship between the intake air pressure PBA and the ventilation outer tube pressure PDA will be described with reference to fig. 3. In the following description, unless otherwise specified, a vehicle equipped with the engine 1 is assumed to travel on a travel path having a relatively low altitude and an atmospheric pressure PA of 760mmHg (hereinafter referred to as "flat ground"), and the intake pressure PBA and the outer ventilation pipe pressure PDA are expressed by absolute pressures.

In the normal state of the state shown in fig. 1, that is, the state in which the breather pipe 7 is appropriately connected to the 2 nd opening 3b of the crankcase 3 and the connection opening 4a of the intake passage 4, the closed space 10 of the breather pipe 7 communicates with the intake manifold 5 of the intake passage 4, which is located on the downstream side of the throttle valve 14, via the communication passage 15. Accordingly, the pressures on both end sides of the communication passage 15, that is, the intake pressure PBA detected by the intake pressure sensor 21 and the ventilation outer tube pressure PDA detected by the outer tube pressure sensor 22, have substantially the same value. Therefore, the ventilation outer tube pressure PDA changes integrally with the intake air pressure PBA as the intake air pressure PBA rises and falls. That is, the intake air pressure PBA and the ventilation outer tube pressure PDA at the same detection time are plotted on or around the 1 st line L1 in fig. 3 (a). In the graph in which the horizontal axis and the vertical axis are set as the intake air pressure PBA and the ventilation outer tube pressure PDA, respectively, the 1 st line L1 shown in fig. 3 (a) is represented by a straight line inclined upward to the right connecting points at which the intake air pressure PBA and the ventilation outer tube pressure PDA become the same value.

On the other hand, for example, when the breather pipe 7 is detached from the crankcase 3 or the intake passage 4 or is broken by the piercing, the breather outer tube pressure PDA becomes a value at or near the atmospheric pressure PA. That is, when the ventilation pipe 7 is detached as described above or a large damage occurs due to the relatively large hole 8a as shown in fig. 4 (a), for example, and the ventilation outer tube pressure PDA becomes equal to the atmospheric pressure PA, the intake air pressure PBA and the ventilation outer tube pressure PDA at the same detection time are plotted on the 2 nd line L2 in fig. 3 (b). In the graph having the same horizontal and vertical axes as the 1 st line L1, the 2 nd line L2 shown in fig. 3 (b) is represented by a horizontal straight line having the same value as the atmospheric pressure PA regardless of the value of the intake air pressure PBA as the ventilation outer tube pressure PDA.

For example, as shown in fig. 4 (b), when a small damage occurs due to the hole 8b that is relatively smaller than the hole 8a in fig. 4 (a), the intake air pressure PBA and the outer ventilation tube pressure PDA at the same detection time are plotted on or around the 3 rd line L3 that is close to the 1 st line L1 in the normal state from the 2 nd line L2 in fig. 3 (b). The 3 rd line L3 shown in fig. 3 (b) is indicated by a straight line which changes in the ventilation outer tube pressure PDA according to the intake air pressure PBA and which is inclined upward and rightward by the intersection of the 1 st line L1 and the 2 nd line L2.

As described above, as shown in fig. 5 (a), the 2 nd line L2 can indicate the relationship between the intake air pressure PBA and the outer ventilation tube pressure PDA when the ventilation pipe 7 is detached or when a relatively large breakage occurs in the ventilation pipe 7, while the 3 rd line L3 can indicate the relationship between the intake air pressure PBA and the outer ventilation tube pressure PDA when a relatively small breakage occurs in the ventilation pipe 7. Therefore, the 3 rd line L3 can be set as a straight line indicating a threshold value for determining whether or not the ventilation pipe 7 has a failure. As shown in fig. 5 (b), a region surrounded by a region not less than the 3 rd line L3 and not less than the 2 nd line L2 is set as a failure determination region where it can be determined that the ventilation pipe 7 has failed, and a region lower than the 3 rd line L3 is set as a normal determination region where it can be determined that the ventilation pipe 7 is normal.

Further, when the absolute pressure is used as the intake pressure PBA and the ventilation outer tube pressure PDA, there are the following problems. That is, when the vehicle mounted with the engine 1 travels on a flat ground, since the absolute pressure of the atmospheric pressure PA is 760mmHg, the presence or absence of a failure in the ventilation pipe 7 can be determined using the failure determination map of fig. 6 (a) having the same 1 st line L1 to 3 rd line L3 as those of fig. 5 (a) and (b) described above. However, when the vehicle mounted with engine 1 travels on a traveling road with a relatively high altitude (hereinafter referred to as "highland"), the absolute value of atmospheric pressure PA is smaller than 760 mmHg. Therefore, when the ventilation pipe 7 fails, as shown in fig. 6 b, the 2 nd line L2 and the 3 rd line L3 in fig. 6 a are shifted in the descending direction (downward in the figure) by the descending amount of the atmospheric pressure PA, and become the 2 nd descending line L2 'and the 3 rd descending line L3', respectively.

In this case, when the failure determination is performed by directly using the map shown in fig. 6 (a), an erroneous determination may occur. For example, when the intake pressure PBA and the outer ventilation pipe pressure PDA reach the point P shown in fig. 6 (b), it is determined that the ventilation pipe 7 has failed because the 3 rd falling line L3' indicating the threshold value is not less than the point P. However, in the map shown in fig. 6 (a), the point P is lower than the 3 rd descending line L3', and therefore the ventilation pipe 7 that should originally be determined to have a failure is erroneously determined to be normal.

In order to avoid the above-described problem, it is preferable to use an intake gauge pressure PBGA and a ventilation outer tube gauge pressure PDGA, which are expressed by gauge pressures based on the atmospheric pressure PA, instead of the absolute pressures of the intake pressure PBA and the ventilation outer tube pressure PDA. That is, the intake air gauge pressure PBGA and the outer ventilation tube gauge pressure pdgf are expressed as follows.

PBGA＝PBA-PA

PDGA＝PDA-PA

Fig. 7 is a map corresponding to fig. 5 (b) for determining a failure of the ventilation pipe 7 by the intake gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA. As shown in fig. 7, the failure determination map displays the 1 st, 2 nd, and 3 rd gauge lines L1G, L2G, and L3G corresponding to the 1 st, 2 nd, and 3 rd lines L1, L2, and L3, respectively, of fig. 5 (b). In the failure determination map of fig. 7, similarly to the map of fig. 5 (b), a region surrounded by the 2 nd gauge line L2G and the 3 rd gauge line L3G can be set as a failure determination region, and a region lower than the 3 rd gauge line L3G can be set as a normality determination region. By using such a failure determination map, even if the atmospheric pressure PA changes, it is possible to appropriately determine the failure of the ventilation pipe 7 without being affected by the change.

Further, the failure determination map shown in fig. 8 (a) may be used. This failure determination map can prevent erroneous determination due to a deviation in detection of the intake air gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA. Specifically, the failure determination map is provided with a determination prohibited area with respect to the map of fig. 7 described above, and the failure determination area is expanded in a direction in which the ventilation outer tube gauge pressure PDGA becomes lower (below (a) of fig. 8).

Here, a method of generating the failure determination map of fig. 8 (a) will be described with reference to fig. 8 (b). As shown in fig. 8 (b), in addition to the 1 st gauge line L1G, the 2 nd gauge line L2G, and the 3 rd gauge line L3G of fig. 7, an upper limit line L1GUP indicating an upper limit of the deviation in the normal state of the 1 st gauge line L1G and a lower limit line L3GDW indicating a lower limit of the deviation in the failure state of the 3 rd gauge line L3G are described. The upper limit line L1GUP is set by adding the maximum deviation width α to the 1 st gauge line L1G. On the other hand, the lower limit line L3GDW is set by subtracting the maximum deviation width β from the 3 rd gauge line L3G.

The intake air gauge pressure PBGA when the upper limit line L1GUP exceeds the lower limit line L3GDW is set as the upper limit value UPLIM of the intake air gauge pressure at the time of failure determination. That is, when the intake air gauge pressure PBGA exceeds the upper limit value UPLIM, there is a high possibility that erroneous determination may occur due to a deviation in detection of the intake air gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA. That is, as shown in fig. 8 (a), a region where the intake air gauge pressure PBGA exceeds the upper limit value UPLIM is set as the determination prohibition region. Further, a region that is above the lower limit line L3GDW and is surrounded between the 2 nd gauge line L2G and is other than the above-described determination prohibited region is set as the failure determination region.

Next, a failure determination process of the ventilation pipe 7 will be described with reference to fig. 9. The ECU 20 repeatedly executes the present process at a predetermined cycle.

In this failure determination process, first, in step 1 (illustrated as "S1". the same applies hereinafter), it is determined whether or not the determination execution condition satisfaction flag F _ JDGOK is "1". The determination execution condition satisfaction flag F _ JDGOK is set to "1" when an execution condition described later of failure determination is satisfied, and is reset to "0" after the determination of the presence or absence of a failure in the present process. If the determination result in step 1 is "no", the process proceeds to step 2, and it is determined whether or not the determination execution condition is satisfied. If the determination result is "no" and the determination condition is not satisfied, the present process is terminated as it is. On the other hand, when the determination result in step 2 is "yes" and the determination execution condition is satisfied, the determination execution condition satisfaction flag F _ JDGOK is set to "1" in order to indicate this (step 3), and the count-up of the timer value TMSTA which is the steady wait timer as the count-up timer is started in order to secure a time for actually stably performing the determination from the time point at which the determination execution condition is satisfied (step 4). Thus, the timer value TMSTA starts counting up from the value 0.

The determination execution condition in step 2 described above is determined whether or not the determination execution condition is satisfied, for example, based on the engine water temperature TW, the intake air gauge pressure PBGA, and the amount of change in the intake air gauge pressure PBGA. Specifically, when the engine water temperature TW is equal to or higher than the predetermined temperature TWREF (TW ≧ TWREF), the intake air gauge pressure PBGA is equal to or lower than the upper limit value UPLIM (PBGA ≦ UPLIM) of fig. 8 (a), and a change amount Δ PBGA of the intake air gauge pressure PBGA, for example, a difference between a previous value and a next value of the intake air gauge pressure PBGA is equal to or lower than the predetermined value Δ pbgarf (Δ PBGA ≦ Δ pbgarf), it is determined that the determination execution condition is satisfied. When any one of the 3 conditions is negative, it is determined that the determination execution condition is not satisfied.

If the determination result of step 1 is yes and F _ JDGOK is 1, that is, if the determination execution condition establishment flag F _ JDGOK has been set to "1" by the execution of step 3 in the previous cycle of the present process because the above-described determination execution condition is established, steps 2 to 4 are skipped and the process proceeds to step 5. Thereby, the count-up of the timer value TMSTA of the steady wait timer continues.

In step 5, it is determined whether or not the timer value TMSTA of the steady wait timer has elapsed a predetermined steady wait time tmsargef (for example, 2 seconds) or more. If the determination result is "no", the present process is terminated as it is. On the other hand, if the determination result in step 5 is yes, it is assumed that a sufficient time for stably performing the failure determination has elapsed and the routine proceeds to step 6.

In this step 6, the threshold PDGATH of the ventilation outer tube gauge pressure is calculated from the intake air gauge pressure PBGA. The threshold PDGATH is calculated using the lower limit line L3GDW of the 3 rd gauge line L3G shown in fig. 8 (a).

Next, at step 7 following step 6, it is determined whether or not the ventilation outer tube gauge pressure PDGA is equal to or greater than the threshold value pdath calculated at step 6 (PDGA ≧ pdath). If the determination result is "yes", that is, if the ventilation outer tube gauge pressure PDGA is within the failure determination region in fig. 8 (a), the routine proceeds to step 8, where it is determined whether the failure determination required time setting completion flag F _ TMJDGNG is "1". If the determination result is "no", the timer value TMJDGNG of the failure determination required time timer as the countdown timer is set to a predetermined determination required time TMJDGREF (for example, 2 seconds) (step 9), and to indicate this, the failure determination required time setting completion flag F _ TMJDGNG is set to "1" (step 10). Accordingly, in the next cycle of the present process, the determination result in step 8 becomes yes, and the process skips steps 9 and 10 and proceeds to step 11.

Note that, although the timer value TMJDGNG of the failure determination required time timer starts the countdown by the execution of step 9, when the determination execution condition is not satisfied (step 2: no), the timer value TMJDGNG is set to temporarily stop by the interrupt processing, and the determination execution condition satisfaction flag F _ JDGOK is reset to "0". After the timer value TMJDGNG is temporarily stopped, when the determination execution condition is satisfied (yes in step 2) and the timer value TMSTA of the steady wait timer becomes equal to or more than the steady wait time tmsaref (yes in step 5), the count-down of the timer value TMJDGNG of the restart failure determination required time timer is set.

In step 11, it is determined whether or not the timer value TMJDGNG of the failure determination required time timer set in step 9 is equal to or less than 0. If the determination result is "no", the present process is terminated as it is. On the other hand, when the determination result in step 11 is yes and the time required for failure determination has elapsed, it is determined that the ventilation pipe 7 has failed, and the failure flag F _ NG is set to "1" to indicate that failure has occurred (step 12).

Then, the failure determination required time setting completion flag F _ TMJDGNG is reset to "0" (step 13), and the determination execution condition satisfaction flag F _ JDGOK is reset to "0" (step 14), and the present process is ended.

On the other hand, when the determination result in step 7 is "no" and the ventilation outer tube gauge pressure PDGA is lower than the threshold value pdath, that is, when the ventilation outer tube gauge pressure PDGA is within the normal determination region in fig. 8 (a), the routine proceeds to step 15, where it is determined whether the normal determination required time setting completion flag F _ TMJDGOK is "1". If the determination result is "no", the timer value TMJDGOK as the normality determination required time timer of the countdown timer is set to a predetermined determination required time TMJDGREF (for example, 2 seconds) (step 16), and the normality determination required time setting completion flag F _ TMJDGOK is set to "1" to indicate this (step 17). Accordingly, in the next cycle of the present process, the determination result in step 15 becomes yes, and the process skips steps 16 and 17 and proceeds to step 18.

The timer value TMJDGOK of the normal determination required time timer is set to temporarily stop and restart the down-counting under the same conditions as the timer value TMJDGNG of the failure determination required time timer.

In step 18, it is determined whether or not the timer value TMJDGOK of the normality determination required time timer set in step 16 is equal to or less than 0. If the determination result is "no", the present process is terminated as it is. On the other hand, when the determination result in step 18 is yes and the time required for the normality determination has elapsed, it is determined that the ventilation pipe 7 is normal, and the normality flag F _ OK is set to "1" to indicate this (step 19).

Thereafter, the flag F _ TMJDGOK for completion of setting the time required for normal determination is reset to "0" (step 20), and the above-mentioned step 14 is executed to end the present process.

Next, the operation in the failure determination process will be described with reference to fig. 10. Fig. 10 (a) shows an example of transition of the intake air gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA, and (b) shows a timing chart of the determination execution condition establishment flag F _ JDGOK, the timer value TMSTA of the steady waiting timer, the timer value TMJDGNG of the failure determination required time timer, and the failure determination flag F _ NG, which change in accordance with the transition of (a).

As shown in fig. 10 (a), until time t1, the intake air gauge pressure PBGA exceeds the upper limit value UPLIM, which is one of the execution conditions for the failure determination, and the determination execution condition is not satisfied (step 2: no), and therefore, as shown in fig. 10 (b), the determination execution condition satisfaction flag F _ JDGOK becomes "0".

Time t1 is a time point when the intake air gauge pressure PBGA becomes equal to or lower than the upper limit value UPLIM (PBGA ≦ UPLIM), and it is determined that the execution condition establishment flag F _ JDGOK becomes "1" by the establishment of other determination execution conditions (water temperature TW and change amount Δ PBGA of intake air gauge pressure) ≦ TWREF (TW ≧ TWREF, Δ PBGA ≦ Δ PBGAREF) (step 3). Thereby, the count-up of the timer value TMSTA of the steady wait timer is started (step 4). Then, when the timer value TMSTA has elapsed the prescribed stabilization waiting time tmsargef (step 5: yes), that is, at time t2, the determination required time TMJDGREF is set to the timer value TMJDGNG of the failure determination required time timer (step 9), whereby the countdown of the timer value TMJDGNG is started.

Thereafter, at time t3, the intake gauge pressure PBGA exceeds the upper limit value UPLIM of the intake gauge pressure (PBGA > UPLIM), and thus, when the determination execution condition is not satisfied, the determination execution condition satisfaction flag F _ JDGOK is reset to "0". Accordingly, the timer value TMSTA of the steady wait timer is reset to a value of 0, and the timer value TMJDGNG of the failure determination required time timer that counts down is temporarily stopped.

Next, at time t4, when the intake air gauge pressure PBGA becomes equal to or less than the upper limit value UPLIM again (PBGA ≦ UPLIM), it is determined that the execution condition satisfaction flag F _ JDGOK becomes "1" (step 3), and the timer value TMSTA of the steady wait timer starts counting up again (step 4). When the timer value TMSTA has elapsed the steady wait time tmsargef at time t5 (yes in step 5), the countdown of the timer value TMJDGNG of the temporary-stopped failure determination required time timer is restarted.

When the timer value TMJDGNG of the failure determination required time timer becomes equal to or less than 0 at time t6 (yes in step 11), the failure determination flag F _ NG becomes "1" (step 12), and it is determined that the ventilation pipe 7 has failed.

As described above in detail, according to the present embodiment, the breather pipe 7 formed of a double pipe is connected between the crankcase 3 and the upstream side of the compressor 12 of the supercharger 2 in the intake passage 4, and the closed space 10 of the breather pipe 7 communicates with the intake manifold 5 via the communication passage 15. By comparing the threshold value pdatah set in accordance with the intake air gauge pressure PBGA, which is the pressure in the intake manifold 5, and the outer ventilation pipe gauge pressure PDGA, it is possible to appropriately and quickly determine a failure of the ventilation pipe 7.

In the embodiment, since the failure determination of the breather pipe 7 is performed when the detected intake air gauge pressure PBGA is equal to or less than the upper limit value UPLIM, it is possible to effectively prevent erroneous determination due to a deviation in the detection of the intake air gauge pressure PBGA and the breather outer tube gauge pressure PDGA. Further, since the intake pipe gauge pressure PBGA and the ventilation outer pipe gauge pressure PDGA, which are pressures based on the atmospheric pressure PA, are used in the failure determination of the ventilation pipe 7, even if the atmospheric pressure PA changes due to, for example, the vehicle traveling on a traveling road having a level difference, the atmospheric pressure PA is not affected by the changes, and the failure of the ventilation pipe 7 can be appropriately performed.

The present invention is not limited to the above-described embodiments, and can be implemented in various forms. For example, in the embodiment, the failure determination of the ventilation pipe 7 is performed using the intake air gauge pressure PBGA and the ventilation outer tube gauge pressure PDGA with respect to the atmospheric pressure PA, but the present invention is not limited to this, and the failure determination may be performed using the intake air pressure PBA and the ventilation outer tube pressure PDA, and the threshold value calculated based on the 3 rd line L3 shown in fig. 5 (b). In the embodiment, the failure of the ventilation pipe 7 provided in the engine 1 including the supercharger 2 is determined, but the present invention can be applied to the determination of the failure of the ventilation pipe or other pipes provided in the engine not including the supercharger.

Further, a check valve (not shown) may be provided at the 2 nd connection port 5b, which is a connection portion between the communication passage 15 and the intake manifold 5. By providing the check valve at the above position, the negative pressure generated in the intake manifold 5 can be prevented from acting on the communication passage 15 and the seal member of the ventilation pipe 7. This can suppress the component performance required for the sealing member, and can reduce the cost by using a relatively inexpensive sealing member.

Further, in the embodiment, the communication passage 15 is connected between the closed space 10 of the ventilation pipe 7 and the intake manifold 5, but the present invention is not limited to this, and the communication passage 15 connected to the closed space 10 may be on the downstream side of the supercharger 2 (compressor 12) in the intake passage 4. That is, the communication passage 15 may be connected to the intake passage 4 upstream of the throttle valve 14. In this case, too, a failure of the ventilation pipe 7 can be appropriately and quickly determined.

The passage area (cross-sectional area) of the communication passage 15 is set to be smaller than a predetermined size for determining that the ventilation pipe 7 is broken when the ventilation pipe 7 is pierced. Accordingly, when a hole having a size exceeding the predetermined size is generated in the ventilation pipe 7, the difference between the ventilation outer tube pressure PDA and the ventilation outer tube gauge pressure PDGA and the normal pressure becomes large. Therefore, the failure of the ventilation pipe 7 can be detected with high accuracy based on the pressure difference.

The detailed configurations of the engine 1 and the breather pipe 7 shown in the embodiment are merely examples, and may be appropriately modified within the scope of the present invention.