JPH10184335A - Device for detecting abnormality in blowby gas passage of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect the abnormality in a blowby gas passage and minimize discharge of blowby gas into the air and a bad influence of the gas upon an internal combustion engine. SOLUTION: When leakage or abnormal passing-through of blowby gas occurs in a blowby gas passage 27, which returns the blowby gas produced in an internal combustion engine 1 onto an intake air passage 12 side, an ISC opening of ISC(Idling engine Speed Control) valve 20 for example as a load during the idling of the internal combustion engine 1 is measured. When the ISC opening is smaller than the prescribed opening, an ECU judges that leakage or abnormal passing-through of the blowby gas occurred in the blowby gas passage 27. Thus, the leakage or abnormal passing-through of the gas in the blowby gas passage 27 can precisely be detected by such a simple and less expensive constitution as detects the load during the idling of the internal combustion engine 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas passage abnormality detecting device for detecting an abnormality in a blow-by gas passage for reducing blow-by gas leaking from a combustion chamber of an internal combustion engine to a crankcase to an intake passage side. .

[0002]

2. Description of the Related Art Conventionally, a blow-by gas is provided in which a blow-by gas passage is provided for a blow-by gas leaking from a combustion chamber of an internal combustion engine to a crankcase, and the blow-by gas is reduced toward an intake passage to prevent the blow-by gas from being released into the atmosphere. Systems are known.

[0003]

However, if an abnormality such as breakage or disconnection of a pipe occurs in the blow-by gas passage, the blow-by gas may be released into the atmosphere, which may be against recent environmental pollution prevention.

Accordingly, the present invention has been made to solve such a problem, and it is an object of the present invention to accurately detect an abnormality in a blow-by gas passage and to minimize the discharge of blow-by gas into the atmosphere and adverse effects on an internal combustion engine. It is an object of the present invention to provide a blow-by gas passage abnormality detection device for an internal combustion engine that can perform the above.

[0005]

According to the blow-by gas passage abnormality detecting device for an internal combustion engine according to the first aspect of the present invention, abnormality in the blow-by gas passage for returning blow-by gas generated in the internal combustion engine to the intake passage side by the abnormality determining means is detected by the internal combustion engine. The determination is made based on the load amount when the operating state of the engine is idling. Therefore, by knowing the load amount when the operation state of the internal combustion engine is idling, abnormality in the blow-by gas passage is accurately detected, and discharge of blow-by gas into the atmosphere and adverse effects on the internal combustion engine are minimized. can do.

In the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present invention, the blow-by gas passage abnormality is accurately detected by a simple and inexpensive configuration in which the load amount is measured using the intake air amount measuring means. Gas emissions into the atmosphere and adverse effects on the internal combustion engine can be minimized.

According to the third aspect of the present invention, the control amount of the idle speed control valve is controlled by the intake air amount measuring means so that the engine speed at the time of idling of the internal combustion engine becomes a predetermined speed. Is measured, and when the control amount is smaller than a predetermined value, the abnormality detecting means determines that the blow-by gas passage is leaking or missing. For this reason, the control amount of the idle speed control valve at the time of idling of the internal combustion engine, that is, the opening degree of the idle speed control valve is smaller than the predetermined value, is that the intake air amount flowing from the other is larger than usual. The determination can be made, and it can be considered that a leak or a dropout abnormality has occurred in the blow-by gas passage. Thus, knowing the opening of the idle speed control valve during idling enables accurate detection of the blow-by gas passage abnormality and minimizes the release of blow-by gas into the atmosphere and adverse effects on the internal combustion engine. Can be.

In the blow-by gas passage abnormality detecting device according to the fourth aspect of the present invention, the control value, that is, the determination value corresponding to the opening of the idle speed control valve is set for each engine speed, so that the load at that time is set. Even if the engine speed changes due to the fluctuation, the abnormality determination for the blow-by gas passage is accurately performed.

According to a fifth aspect of the present invention, the air-fuel ratio of the internal combustion engine is measured by the intake air amount measuring means, and when the air-fuel ratio is higher than a predetermined value, the abnormality judging means detects the air-fuel ratio of the blow-by gas passage. It is determined that there is a leak or a dropout abnormality. For this reason, when the air-fuel ratio of the internal combustion engine is higher than a predetermined value, it can be determined that the amount of intake air flowing from the other is larger than usual, and it is considered that a leak or a dropout abnormality has occurred in the blow-by gas passage. Can be. By knowing the air-fuel ratio of the internal combustion engine in this way, an abnormality in the blow-by gas passage can be accurately detected, and discharge of blow-by gas into the atmosphere and adverse effects on the internal combustion engine can be minimized.

In the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present invention, the judgment value corresponding to the air-fuel ratio is set for each engine speed. The abnormality determination for the gas passage is accurately performed.

In the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present invention, the intake pressure is higher than a predetermined value by a simple and inexpensive configuration in which the pressure detection means is used to detect the intake pressure corresponding to the load amount. In some cases, it can be determined that another pressure (atmospheric pressure) is exerting an effect, and it can be considered that a leak or a dropout abnormality has occurred in the blow-by gas passage. By knowing the intake pressure corresponding to the load amount of the internal combustion engine, it is possible to accurately detect the abnormality of the blow-by gas passage and minimize the discharge of the blow-by gas into the atmosphere and the adverse effect on the internal combustion engine. it can.

In the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present invention, the judgment value corresponding to the intake pressure is set for each engine speed. The abnormality determination for the gas passage is accurately performed.

According to a ninth aspect of the present invention, the abnormality of the blow-by gas passage is determined when various devices in the intake system of the internal combustion engine are normal. For this reason, the abnormality of the blow-by gas passage is accurately detected.

In the blow-by gas passage abnormality detecting device according to a tenth aspect, the abnormality of the blow-by gas passage is determined when various devices related to combustion of the internal combustion engine are normal. For this reason, the abnormality of the blow-by gas passage is accurately detected.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples.

Embodiment 1 FIG. 1 is a schematic diagram showing an entire configuration of a blow-by gas passage abnormality detecting device for an internal combustion engine according to a first embodiment of the present invention.

In FIG. 1, in the intake system of the internal combustion engine 1,
The air introduced from the air cleaner 11 on the upstream side is supplied to the air flow meter 33 disposed in the intake passage 12 and the intake passage 1.
The fuel gas is mixed with fuel injected and supplied from an injector 16 in an intake manifold 15 through a throttle valve 13 disposed downstream of the throttle valve 13 and a surge tank 14 on the downstream side of the throttle valve 13. It is introduced into the combustion chamber 21 of each cylinder. In the middle of a bypass passage 19 connected around the throttle valve 13, the engine speed during idling is controlled to a predetermined speed.
An SC (Idle Speed Control) valve 20 is provided. Then, in the exhaust system of the internal combustion engine 1, the exhaust gas from the combustion chamber 21 is purified from the exhaust valve 22 through the exhaust port 23 and the exhaust passage 24 by the three-way catalytic converter (not shown), and is discharged into the atmosphere. The air flow meter 33 detects the amount of intake air passing through the intake passage 12. An oxygen concentration sensor 25 for detecting the concentration of oxygen (O ₂ ) in the exhaust gas is provided upstream of the three-way catalytic converter in the exhaust passage 24.

On the other hand, blow-by gas leaking into the crankcase 4 from the combustion chamber 21 through the gap between the piston 2 and the cylinder wall 3 during the combustion stroke of each cylinder of the internal combustion engine 1 Through the communication passage 5 and into the head cover 6 of the internal combustion engine 1. The upper part of the head cover 6 is connected to the intake passage 12 via the communication passage 26 and to the surge tank 14 on the downstream side of the throttle valve 13 via the blow-by gas passage 27. In the middle of the blow-by gas passage 27, a PCV (Positive Crankcase Ventilation) valve 28 which is a negative pressure (differential pressure) driven flow control valve having a known configuration.
Are arranged.

The PCV valve 28 is connected to the surge tank 1
The opening / closing control is performed by the negative pressure in the intake tank 4. When the negative pressure as the intake pressure is large, such as during idling, the air passage area becomes small, and the amount of blow-by gas flowing from the head cover 6 into the surge tank 14 becomes small. When the negative pressure as the intake pressure is small, the air passage area increases,
The amount of blow-by gas flowing from the head cover 6 into the surge tank 14 is large.

That is, when the inside of the surge tank 14 becomes a negative pressure, the inside of the head cover 6 is moved from the inside of the intake passage 12 to the communication passage 2.
The blow-by gas in the head cover 6 is ventilated by the fresh air introduced through the blower 6, passes through the blow-by gas passage 27, and its flow rate is adjusted by the PCV valve 28, and is returned into the surge tank 14 as an intake system.

Reference numeral 40 denotes an ECU (Electronic Control Unit).
The ECU 40 includes a CPU serving as a well-known central processing unit (not shown), a ROM storing a control program, a RAM storing various data, a B / U (backup) RAM, an input / output circuit, and connecting them. It is configured as a logical operation circuit including a bus line and the like. A signal relating to the oxygen concentration in the exhaust passage 24 from the oxygen concentration sensor 25, a signal relating to the amount of intake air passing through the intake passage 12 from the air flow meter 33, and the like are input to the ECU 40, and are provided from the ECU 40 to the intake manifold 15. Drive signals are output to the injector 16 and the ISC valve 20 disposed in the bypass passage 19, respectively.

Next, a description will be given of a processing procedure of abnormality determination in the ECU 40 used in the blow-by gas passage abnormality detecting device of the internal combustion engine according to the first embodiment of the present invention with reference to a flowchart of FIG. .

In FIG. 2, in step S101, it is determined whether the operating state of the internal combustion engine 1 is idling.
If the determination condition of step S101 is not satisfied and the time is other than the time of idling, this routine is ended without doing anything.
On the other hand, when the determination condition in step S101 is satisfied, that is, when the throttle opening of the throttle valve 13 is equal to or less than the predetermined value and the engine is idling, the process proceeds to step S102, and when the current ISC opening of the ISC valve 20 is less than the determination value A, It is determined whether there is. This determination value A is used for the blow-by gas passage 2
If 7 is normal, it is set to the impossible ISC opening at the time of idling.

The reason for setting the determination value A is that if the blow-by gas passage 27 is normal, for example, the control duty ratio of the ISC valve 20 is usually 20 to 30%, whereas the blow-by gas passage If there is a leak or omission in the valve 27, an extra intake of air that cannot be supplied from the side of the blow-by gas passage 27 will occur, and the control duty ratio of the ISC valve 20 will drop to near 0%. In addition,
The determination value A may be set for each engine speed so as to increase as the engine speed increases, as shown in the table of FIG.

If the condition of step S102 is not satisfied,
If the ISC opening is equal to or greater than the determination value A, the process proceeds to step S1.
03, the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is determined to be normal, and this routine ends. On the other hand, when the determination condition of step S102 is satisfied and the ISC opening is less than the determination value A, it is considered that the blow-by gas passage 27 is leaking or missing, and the process proceeds to step S104, where the surge tank It is determined that the blow-by gas passage 27 up to 14 is leaking or missing. Next, the process proceeds to step S105, where the after-abnormality determination process described later is executed, and the routine ends. In this way, the abnormal (leakage or missing) state of the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is accurately detected.

Next, step S10 of FIG. 2 in the ECU 40 used in the blow-by gas passage abnormality detecting device of the internal combustion engine according to the first embodiment of the present invention.
5 will be described with reference to the flowchart of FIG. In addition, since it is determined that an abnormality (leakage or omission) has occurred in the blow-by gas passage 27, the reliability of the following various detection processing and control processing cannot be maintained, and therefore, such processing is prohibited.

In FIG. 4, first, in step S201, the failure detection of the air flow meter 33 for detecting the amount of intake air in the intake passage 12 is prohibited. In the next step S202, the failure detection of the ISC valve 20 is prohibited. In S203, the failure detection of the ISC system is prohibited, and in the next step S204, EGR (Exhaust Gas Recircul
ation: Exhaust gas recirculation) The failure detection of the system (not shown in FIG. 1) is prohibited, and in the next step S205, the failure detection of the fuel system (fuel injection time control etc.) is prohibited.

Next, the process proceeds to step S206, in which misfire detection is prohibited. In the next step S207, the F / B (feedback) of the idle speed in the ISC system is performed.
Control is prohibited (or the gain is reduced), and the next step S
At 208, the A / F (air-fuel ratio) learning control is prohibited (or the main A / F is prohibited or the gain is reduced). At the next step S209, the EGR control is prohibited (or the gain is reduced). Purg
e: Purification) control is prohibited (or the gain is reduced), and this routine ends.

As described above, the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment converts blow-by gas generated in the internal combustion engine 1 based on the load amount when the operation state of the internal combustion engine 1 is idle. ECU 4 for determining abnormality of blow-by gas passage 27 returning to the side of intake passage 12
0 is provided with an abnormality determination means achieved at 0.
Therefore, by knowing the load amount when the operating state of the internal combustion engine 1 is idling, the abnormality of the blow-by gas passage 27 is accurately detected, and the discharge of the blow-by gas into the atmosphere and the adverse effect on the internal combustion engine 1 are reduced. Can be minimized.

The blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment accurately detects an abnormality in the blow-by gas passage 27 by a simple and inexpensive configuration in which the load amount is measured using an intake air amount measuring means. Thus, the release of blow-by gas into the atmosphere and the adverse effect on the internal combustion engine 1 can be minimized.

In the blow-by gas passage abnormality detecting device for the internal combustion engine according to the present embodiment, the ISC valve 20 for controlling the engine speed during idling of the internal combustion engine 1 to a predetermined speed by the intake air amount measuring means. ISC as quantity
The opening degree is measured, and when the ISC opening degree is smaller than the predetermined value A as a predetermined value, the abnormality determining means achieved by the ECU 40 determines that the blow-by gas passage 27 is leaking or missing. For this reason, the ISC measured by the intake air amount measuring means when the internal combustion engine 1 is idling.
The reason why the control amount of the valve 20, that is, the ISC opening is smaller than the predetermined value, can be determined to be that the amount of intake air flowing from another is larger than usual, and a leak or a dropout abnormality has occurred in the blow-by gas passage 27. Can be considered. As described above, by knowing the ISC opening of the ISC valve 20 at the time of idling, the abnormality of the blow-by gas passage 27 is accurately detected, and the discharge of the blow-by gas into the atmosphere and the adverse effect on the internal combustion engine 1 are minimized. be able to.

Further, in the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment, a judgment value A corresponding to the ISC opening as a control amount is set for each engine speed.
Therefore, even if the engine speed changes due to the load fluctuation, the abnormality determination for the blow-by gas passage 27 is accurately performed.

Further, in the present embodiment, the presence or absence of an abnormality is determined when the engine is idling. However, the engine speed of the internal combustion engine 1 is added to the execution conditions, and a predetermined speed (for example, 1
If the abnormality presence / absence determination is performed at the time of idling of 000 rpm or less, erroneous determination in a transient state such as deceleration is prevented, and the accuracy of the abnormality determination is improved.

<Embodiment 2> FIG. 5 is a flowchart showing a procedure for determining an abnormality in the ECU 40 used in the blow-by gas passage abnormality detecting apparatus for an internal combustion engine according to a second embodiment of the present invention. . The general configuration of the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment is the same as the schematic diagram of FIG. 1 in the above-described first embodiment, and the drawings and detailed description thereof are omitted.

In FIG. 5, in step S301, it is determined whether the operating state of the internal combustion engine 1 is idling.
If the determination condition in step S301 is not satisfied and the time is other than the time of idling, the routine ends without doing anything.
On the other hand, when the determination condition in step S301 is satisfied, that is, when the throttle opening of the throttle valve 13 is equal to or less than the predetermined value and the engine is idling, the process proceeds to step S302, and the current A / F based on the output from the oxygen concentration sensor 25 ( It is determined whether the (air-fuel ratio) F / B (feedback) amount exceeds the determination value B. If the blow-by gas passage 27 is normal, the determination value B is an impossible A / F at idle.
The F / B amount is set.

The basis for setting the determination value B is that if the blow-by gas passage 27 is normal, the A / FF / B amount does not fluctuate greatly, whereas the blow-by gas passage 27 leaks or escapes. If there is, an extra intake air supply which cannot be performed from the blow-by gas passage 27 side occurs and the A / F
This is because the F / B amount fluctuates greatly. The determination value B
May be set for each engine speed so as to increase as the engine speed increases, as shown in the table of FIG. Further, in the abnormality determination of the present embodiment, the A / F F / B amount is compared with the determination value.
The same effect can be expected even if the sum of the FF / B amount and the A / FF / B learning value is compared with the determination value.

If the condition of step S302 is not satisfied,
When the A / F F / B amount is equal to or less than the determination value B, the process proceeds to step S303, and it is determined that the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is normal.
This routine ends. On the other hand, when the determination condition of step S302 is satisfied and the A / FF / B amount exceeds the determination value B, it is considered that the blow-by gas passage 27 is leaking or missing, and the process proceeds to step S304. It is determined that the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is leaking or missing. Next, the processing shifts to step S305, and FIG.
The same post-abnormality determination processing as described above is executed, and this routine ends. In this manner, an abnormal (leakage or missing) state of the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is accurately detected.

As described above, the blow-by gas passage abnormality detecting device of the present embodiment measures the A / F / B amount of the internal combustion engine 1 by the intake amount measuring means, and the A / F is set as a predetermined value. When the determination value B is higher than the determination value B, the abnormality determination means achieved by the ECU 40 determines that the blow-by gas passage 27 is abnormally leaking or missing. For this reason, the internal combustion engine 1
If the A / F is higher than the predetermined value, it can be determined that the amount of intake air flowing from the other is larger than usual, and it can be considered that a leak or a dropout abnormality has occurred in the blow-by gas passage 27. Thus, the A / F of the internal combustion engine 1
By knowing this, the abnormality of the blow-by gas passage 27 can be accurately detected, and discharge of blow-by gas into the atmosphere and adverse effects on the internal combustion engine 1 can be minimized.

Further, in the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment, a determination value B corresponding to A / F is set for each engine speed. Therefore, even if the engine speed changes due to the load fluctuation, the abnormality determination for the blow-by gas passage 27 is accurately performed.

<Embodiment 3> FIG. 7 is a flowchart showing a procedure for determining an abnormality in the ECU 40 used in the blow-by gas passage abnormality detecting apparatus for an internal combustion engine according to a third embodiment of the present invention. . The overall configuration of the blow-by gas passage abnormality detection device for an internal combustion engine according to the present embodiment detects the intake pressure in the surge tank 14 following the intake passage 12 as compared with the schematic diagram of FIG. Since the intake pressure sensor is provided, the drawing and its detailed description are omitted.

In FIG. 7, in step S401, it is determined whether the operating state of the internal combustion engine 1 is idling.
If the determination condition of step S401 is not satisfied and the time is other than the time of idling, this routine ends without doing anything.
On the other hand, when the determination condition of step S401 is satisfied, that is, when the throttle opening of the throttle valve 13 is equal to or less than the predetermined value and the engine is idling, the process proceeds to step S402, and the current intake pressure of the intake pressure sensor exceeds the determination value C. Is determined. If the blow-by gas passage 27 is normal, the determination value C is set to an intake pressure at the time of idling which is impossible.

The basis for setting the determination value C is that if the blow-by gas passage 27 is normal, the intake pressure is within a predetermined negative pressure range, whereas if the blow-by gas passage 27 leaks or This is because the positive pressure close to the atmospheric pressure from the gas passage 27 side is supplied to the intake air amount, so that the pressure increases beyond a predetermined negative pressure range. The determination value C may be set for each engine speed so as to increase as the engine speed increases, as shown in the table of FIG.

If the determination condition of step S402 is not satisfied,
When the intake pressure is equal to or less than the determination value C, step S403
Then, it is determined that the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is normal, and the routine ends. On the other hand, if the determination condition of step S402 is satisfied and the intake pressure exceeds the determination value C, it is considered that the blow-by gas passage 27 is leaking or missing, and the process proceeds to step S404, where the surge tank It is determined that the blow-by gas passage 27 up to 14 is leaking or missing. Next, the procedure proceeds to step S405, where the same post-abnormality determination processing as in FIG. 4 described above is executed, and this routine ends. In this way, the abnormal (leakage or missing) state of the blow-by gas passage 27 from the head cover 6 to the surge tank 14 is accurately detected.

As described above, according to the blow-by gas passage abnormality detecting device for an internal combustion engine of the present embodiment, the load amount is the intake pressure detected by the pressure detecting means including the intake pressure sensor, and the intake pressure is a predetermined value. When the value is higher than the determination value C as a value, the abnormality determination means achieved by the ECU 40 determines that the blow-by gas passage 27 is abnormally leaking or missing. That is, with a simple and inexpensive configuration in which an intake pressure sensor corresponding to a load is detected using an intake pressure sensor as a pressure detecting means, when the intake pressure is higher than a predetermined value, the pressure (atmospheric pressure) from other sources is reduced. It can be determined that there is an influence, and it can be considered that a leak or a dropout abnormality has occurred in the blow-by gas passage 27. By knowing the intake pressure corresponding to the load amount of the internal combustion engine 1 in this manner, the abnormality of the blow-by gas passage 27 is accurately detected, and the discharge of the blow-by gas into the atmosphere and the adverse effect on the internal combustion engine 1 are minimized. can do.

Further, in the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment, a judgment value C corresponding to the intake pressure is set for each engine speed. Therefore, even if the engine speed changes due to the load fluctuation, the abnormality determination for the blow-by gas passage 27 is accurately performed. Further, the accuracy of the abnormality determination is further improved by performing the correction based on the atmospheric pressure in the determination value C.

By the way, before the abnormality determination of the blow-by gas passage 27 in the above-described embodiment, a normal / abnormality determination routine for intake system equipment as shown in FIG. 9 may be added. That is, in step S501, the air flow meter 33,
In step S502, the ISC valve 20 and step S50
In step S504, a normal / abnormal judgment is performed by a throttle sensor (not shown) for detecting the throttle opening of the throttle valve 13, and an atmospheric pressure sensor (not shown) for detecting the atmospheric pressure in step S504. In some cases, diagnosis is permitted in step S505 to perform abnormality determination of the blow-by gas passage 27. If at least one of the devices is abnormal, diagnosis is prohibited in step S506, and the routine ends. Thereby, the blow-by gas passage 27
Can be more accurately determined.

Further, in the above embodiment, the internal combustion engine (the so-called L-type engine) which controls the fuel injection by measuring the amount of intake air into the intake passage.
J engine) and the air flow meter 33 is provided, but when the present invention is implemented,
However, the present invention is not limited to this. In an internal combustion engine (a so-called DJ engine) that performs fuel injection control by measuring the pressure in the intake passage, the intake pressure detected by an intake pressure sensor (not shown) is used as the blow-by gas passage. 27 may be used for abnormality determination.

Then, a normal / abnormal judgment routine for a device related to a combustion system as shown in FIG. 10 can be added to the above embodiment. That is, the injector 16 is determined in step S601, the ignition coil (not shown) is determined in step S602, and the pressure regulator (not illustrated) is determined in step S603 as normal / abnormal. If all devices are normal, the blow-by gas is determined in step S604. Diagnosis permission for performing the abnormality determination of the passage 27 is determined to be permitted. If at least one of the devices is abnormal, step S6 is performed.
At 05, the diagnosis is prohibited, and the routine ends. Thereby, the accuracy of the abnormality determination of the blow-by gas passage 27 can be improved.

Further, a diagnosis permission / prohibition routine at the time of electric load fluctuation as shown in FIG. 11 can be added to the above embodiment. That is, when there is a change from ON to OFF or OFF to ON with respect to the electric load in step S701, the initial value is set in the timer T in step S702, and when there is no change in the electric load in step S701, the timer is set in step S703. T is subtracted, and step S70 is performed.
It is determined whether or not the timer T has reached "0" in step 4, and the timer T
Is "0", diagnosis is permitted in step S705 to perform an abnormality determination of the blow-by gas passage 27. If the timer is not "0" and the predetermined time has not elapsed since the electric load change, the diagnosis is prohibited in step S706. And terminates this routine. Thereby, the blow-by gas passage 2
7 can improve the accuracy of the abnormality determination.

Furthermore, in the above-described embodiment, the PCV valve 28 as a flow regulating valve which is disposed in the middle of the blow-by gas passage 27 and driven by negative pressure is used. Without limitation, E
An electromagnetically driven valve or the like that can control the flow rate from the CU 40 side may be used. In this case, the determination value in the abnormality determination of the blow-by gas passage 27 may be made variable by the control flow rate.

As described above, the blow-by gas passage abnormality detecting device for an internal combustion engine according to the present embodiment determines the abnormality of the blow-by gas passage 27 by the ECU 40 by using the air flow meter 33 and the ISC valve 2 as various devices of the intake system of the internal combustion engine 1.
0, which is performed when the throttle sensor, the atmospheric pressure sensor, and the like are normal. For this reason, the abnormality of the blow-by gas passage 27 is accurately detected.

The abnormality detection device for the blow-by gas passage of the internal combustion engine according to the present embodiment determines the abnormality of the blow-by gas passage 27 by the ECU 40 by using the injector 16, the ignition coil, and the pressure regulator as various devices related to the combustion of the internal combustion engine 1. Etc. are performed when they are normal. For this reason, the abnormality of the blow-by gas passage 27 is accurately detected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a blow-by gas passage abnormality detection device for an internal combustion engine according to a first example of an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of an abnormality determination in an ECU used in a blow-by gas passage abnormality detection device for an internal combustion engine according to a first example of an embodiment of the present invention.

FIG. 3 is a table showing a change in a determination value according to an engine speed in the routine of FIG. 2;

FIG. 4 is a flowchart showing a processing procedure after an abnormality determination in an ECU used in a blow-by gas passage abnormality detection apparatus for an internal combustion engine according to the first to third examples of the embodiment of the present invention. It is.

FIG. 5 is a flowchart showing a processing procedure of abnormality determination in an ECU used in a blow-by gas passage abnormality detection device for an internal combustion engine according to a second example of the embodiment of the present invention.

FIG. 6 is a table showing a change in a determination value in the routine of FIG. 5 according to an engine speed;

FIG. 7 is a flowchart showing a processing procedure of abnormality determination in an ECU used in a blow-by gas passage abnormality detection device for an internal combustion engine according to a third embodiment of the present invention.

FIG. 8 is a table showing a change in a determination value according to the engine speed in the routine of FIG. 7;

FIG. 9 is a flowchart showing a normal / abnormal judgment procedure for an intake system device or the like which can be added to the blow-by gas passage abnormality detecting device of the internal combustion engine according to the first to third examples of the embodiment of the present invention. It is.

FIG. 10 shows a normal / abnormal judgment procedure for a device relating to a combustion system which can be added to the blow-by gas passage abnormality detecting device of the internal combustion engine according to the first to third examples of the embodiment of the present invention. It is a flowchart.

FIG. 11 is a diagram showing an example of a diagnostic permission / change at the time of electric load fluctuation which can be added to the blow-by gas passage abnormality detecting device of the internal combustion engine according to the first to third examples of the embodiment of the present invention.
It is a flowchart which shows a prohibition procedure.

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine 6 head cover 12 intake passage 14 surge tank 27 blow-by gas passage 28 PCV valve 33 air flow meter 40 ECU (electronic control device)

Claims (10)

[Claims] 1. A blow-by gas passage for returning blow-by gas generated in an internal combustion engine to an intake passage side of the internal combustion engine; and an abnormality in the blow-by gas passage based on a load amount when an operation state of the internal combustion engine is idling. A blow-by gas passage abnormality detection device for an internal combustion engine, comprising: 2. The blow-by gas passage abnormality detecting device for an internal combustion engine according to claim 1, wherein the load amount is measured using an intake air amount measuring unit. 3. The intake air amount measuring means measures a control amount of an idle speed control valve for controlling an engine speed of the internal combustion engine during idling to be a predetermined speed, and the control amount is a predetermined value. The blow-by gas passage abnormality detecting device for an internal combustion engine according to claim 2, wherein the abnormality determining means determines that the blow-by gas passage is leaking or missing when the number is smaller. 4. The apparatus according to claim 3, wherein the judgment value corresponding to the control amount is set for each engine speed. 5. The intake air amount measuring means measures an air-fuel ratio of the internal combustion engine, and when the air-fuel ratio is higher than a predetermined value, the abnormality judging means judges that the blow-by gas passage is leaky or missing. 3. The method according to claim 2, wherein
3. The blow-by gas passage abnormality detection device for an internal combustion engine according to claim 1. 6. The apparatus according to claim 5, wherein the determination value corresponding to the air-fuel ratio is set for each engine speed. 7. The load amount is an intake pressure detected by a pressure detection unit, and when the intake pressure is higher than a predetermined value, the abnormality determination unit determines that the blow-by gas passage is leaking or missing. The blow-by gas passage abnormality detecting device for an internal combustion engine according to claim 1, wherein the abnormality is determined. 8. The blow-by gas passage abnormality detecting device for an internal combustion engine according to claim 7, wherein the determination value corresponding to the intake pressure is set for each engine speed. 9. The abnormality determination of the blow-by gas passage is performed as follows:
9. The blow-by gas passage abnormality detection apparatus for an internal combustion engine according to claim 1, wherein the apparatus is executed when various devices of an intake system of the internal combustion engine are normal. 10. The apparatus according to claim 1, wherein the determination of the abnormality of the blow-by gas passage is performed when various devices related to combustion of the internal combustion engine are normal. The blow-by gas passage abnormality detecting device for an internal combustion engine according to the above.