JP2010059922A - Egr device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the amount of EGR gas from being excessively increased and secure torque even when EGR valves installed in an EGR passage are stuck open. <P>SOLUTION: The EGR device of an internal combustion engine includes: an internal combustion engine having a plurality of banks: one or more EGR passages for taking out a part of the exhaust gas from predetermined EGR takeout banks which are a part of the plurality of banks and making the exhaust gas as an EGR gas into an intake passage; the EGR valves installed in the EGR passages, an intake amount control means for controlling the intake amount of each EGR takeout bank; a fault detection means for detecting the opened seizure of each EGR valve; and fault control means for more reducing the sucked amount of the EGR takeout banks which is constituted so as to take out the part of the exhaust gas as the EGR gas by the EGR passages in which the open-seized EGR valves are installed among the EGR takeout banks when the opened seizure of the EGR valves is detected than that when the EGR valves are not stuck open. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an EGR device for an internal combustion engine.

  A technique is known in which an exhaust passage and an intake passage of an internal combustion engine are connected by an EGR passage, and a part of the exhaust from the internal combustion engine flows into the intake passage as EGR gas through the EGR passage.

  The EGR gas amount can be adjusted by adjusting the opening degree of the EGR valve provided in the EGR passage. However, when the EGR valve is fixed, the EGR gas amount cannot be adjusted.

  In particular, when the EGR valve is stuck in the open state, the amount of EGR gas becomes excessive, and there is a possibility that problems such as combustion failure such as misfire and insufficient torque may occur.

On the other hand, when the EGR valve is stuck in the open state, the internal combustion engine is reduced in cylinder operation and the intake air amount is increased, thereby reducing the EGR rate per cylinder and stabilizing the combustion. Has been proposed (see Patent Document 1).
JP-A-2005-207285 Japanese Patent Laid-Open No. 9-25852 Japanese Patent Laid-Open No. 11-22561

  However, when the opening degree of the EGR valve stuck in the valve open state is large, it is not possible to sufficiently suppress an excessive amount of EGR gas, or sufficient torque for evacuation traveling can be obtained by reduced-cylinder operation. There was a risk of not.

  The present invention has been made in view of such circumstances, and even when the EGR valve provided in the EGR passage is stuck open, it is possible to suppress an excessive amount of EGR gas and to perform retreat traveling. An object of the present invention is to provide a technique that makes it possible to ensure a sufficient torque.

In order to achieve the above object, an EGR device for an internal combustion engine of the present invention comprises:
An internal combustion engine having a plurality of banks;
One or a plurality of EGR passages that take out at least a part of the exhaust from a bank with a predetermined EGR take-out that is a part of the plurality of banks and flow into the intake passage of the internal combustion engine as EGR gas;
An EGR valve provided in each EGR passage;
An intake air amount control means for controlling an intake air amount flowing into the bank with each EGR take-out,
A failure detection means for detecting open adhesion of each EGR valve;
When the failure detection means detects that the EGR valve is stuck open, a part of the exhaust gas is taken out as EGR gas by the EGR passage provided with the opened EGR valve in the EGR take-out bank. And a failure-time control means for reducing the intake air amount of the EGR take-out bank configured as described above from the normal time when the EGR valve is not open and fixed.

When the EGR valve is open and fixed, the flow area of the EGR passage provided with the open and fixed EGR valve becomes larger than usual. Therefore, when the same amount of exhaust gas as normal flows into the EGR passage from the exhaust passage, a larger amount of EGR gas than normal can flow into the intake passage through the EGR passage.

  In this sense, hereinafter, an EGR take-out bank configured such that a part of the exhaust gas is taken out as EGR gas by the EGR passage provided with the open and fixed EGR valve is referred to as an “EGR take-out increase bank”.

  According to the present invention, when it is detected that the EGR valve is open and stuck, the amount of intake air flowing into the EGR take-out increase bank is reduced as compared with the normal time, so the amount of exhaust discharged from the EGR take-out increase bank is reduced. .

  Accordingly, only a smaller amount of exhaust gas flows into the EGR passage provided with the open-fixed EGR valve than usual.

  Therefore, even if the EGR passage provided with the open-fixed EGR valve is in a state where a larger amount of EGR gas than normal can flow due to the open-fixation of the EGR valve, the EGR valve actually It is possible to prevent the amount of EGR gas flowing into the intake passage via the passage from being excessive as compared with the normal time.

  Thereby, even when the EGR valve is stuck open, it is possible to suppress the occurrence of problems such as poor combustion and insufficient torque.

  Here, when the amount of EGR gas flowing into the intake passage becomes excessive due to the open fixing of the EGR valve, the opening degree of the open and fixed EGR valve is determined according to the operating condition of the internal combustion engine. As an example, the opening degree on the open side can be exemplified.

  Conversely, even if the EGR valve is stuck in the open state, the amount of EGR gas is unlikely to be excessive if the degree of opening of the stuck EGR valve is equal to or less than the target EGR valve opening.

  Therefore, the failure time control means of the present invention, when detecting the sticking of the EGR valve, operates under such operating conditions that the opening degree of the open and stuck EGR valve is the opening degree on the opening side with respect to the target EGR valve opening degree. For example, the above-described EGR extraction increase bank intake air amount reduction control may be performed.

  In the present invention, if the failure time control means reduces the intake air amount of all EGR take-out increase banks when the EGR valve is stuck open, the excessive amount of EGR gas when the EGR valve is stuck open is preferably suppressed. , The problem of combustion failure and torque shortage can be more reliably suppressed, but even if the intake air amount of at least one EGR take-out increase bank is reduced, the EGR gas amount is suppressed from being excessive when the EGR valve is stuck open, and combustion This has the effect of reducing the problems of defects and insufficient torque.

  Further, the failure time control means may reduce the intake air amount of all EGR removal banks when the EGR valve is stuck open. In this case, it is conceivable that the intake air amount is also reduced in the bank with EGR extraction configured such that a part of the exhaust gas is extracted as EGR gas by the EGR passage where the EGR valve is not open and fixed, It becomes possible to avoid the problem of poor combustion and insufficient torque due to an excessive amount of EGR gas.

Further, in the present invention, the intake air amount control means may be means capable of individually controlling the intake air amount of each bank with EGR extraction, or means for uniformly controlling the intake air amounts of a plurality of banks with EGR extraction. There may be.

  In the former case, the failure time control means of the present invention, when it is detected that the EGR valve is stuck open, out of the banks with EGR extraction, the banks that are not EGR extraction increase banks are subject to intake air amount reduction control. You may not make it.

  By doing this, an EGR take-out bank in which the EGR valve operates normally and the EGR gas amount can be controlled according to the target value is not subject to intake air amount reduction control. Therefore, the EGR gas at the time of detecting the EGR valve open sticking is detected. Quantity control can be performed with higher accuracy.

  Note that banks that are not EGR take-out increase banks may be subject to intake air amount reduction control as in the case of EGR take-out increase banks.

  In the latter case, the failure-time control means of the present invention uniformly reduces the intake air amount of the bank with the EGR take-out when it is detected that the EGR valve is stuck open.

  In the present invention, when a plurality of EGR passages are provided and a plurality of EGR valves are provided, the failure detection means may detect open adhesion of each EGR valve individually. It may be detected that there is an open and fixed one of the EGR valves.

  In the former case, since the open EGR valve can be specified, it is possible to control the target of the intake air amount decrease control by the failure time control means to the EGR take-out increase bank.

  In the latter case, when at least one EGR valve is fixed open, the intake air amount reduction control is performed by the failure control means, so that it is possible to more reliably suppress the occurrence of problems due to excessive EGR gas amount.

  In the present invention, the failure-time control means may further reduce the intake air amount of the EGR take-out increase bank as the opening degree of the open and fixed EGR valve is the opening side.

  By doing so, the amount of exhaust gas discharged from the EGR take-out increase bank is further reduced. Therefore, even when the EGR valve is opened and fixed in a large opening state such as a fully opened state, the amount of EGR gas is increased. It becomes possible to more reliably suppress the excess of.

In the present invention, as a specific means for reducing the intake amount of the EGR take-out increase bank at the time of detecting the open adhesion of the EGR valve,
Further comprising individual intake passages individually connected to the EGR take-out banks,
The intake air amount control means has an individual throttle valve provided in each individual intake passage,
When the failure detecting means detects that the EGR valve is stuck open, the failure time control means determines the opening degree of the individual throttle valve provided in the individual intake passage connected to the EGR take-out increase bank. You may make it make it the opening degree of a close side rather than the normal time when the valve has not adhered.

  In this way, by reducing the individual throttle valve provided in the individual intake passage of the EGR take-out increase bank, the intake amount of the EGR take-out increase bank can be reduced. Therefore, even when the EGR valve is fixed open, EGR An excessive gas amount can be suppressed.

Further, according to the above configuration, since the individual throttle valve opening degree of each EGR take-out bank can be controlled independently, the intake air amount control means configured as described above can control the intake air amount in the EGR take-out bank. It can be controlled individually.

  Therefore, it is also possible to perform control so that the intake air amount is decreased only when the EGR valve is stuck open, particularly for the EGR take-out increase bank.

  As described above, when the intake amount of the EGR take-out increase bank is decreased by closing the individual throttle valve provided in the individual intake passage of the EGR take-out increase bank, the opening degree of the open EGR valve is fixed. The more the opening is on the opening side, the more the individual throttle valve provided in the individual intake passage of the EGR extraction increasing bank may be set to the opening on the more closed side.

  In this way, the intake air amount of the EGR take-out increase bank can be further reduced.

In the present invention, as a specific means for reducing the intake amount of the EGR take-out increase bank at the time of detecting the open adhesion of the EGR valve,
The intake air amount control means has an intake VVT mechanism capable of variably controlling the intake valve timing of the cylinders in the bank with each EGR take-out,
When the failure detecting means detects that the EGR valve is stuck open, the failure time control means sets the closing timing of the intake valve of the cylinder of the EGR take-out increase bank from the normal time when the EGR valve is not stuck. May be retarded.

  As described above, the intake air amount of the EGR take-out increase bank can be reduced by delaying the valve closing timing of the intake valve of the cylinder of the EGR take-out increase bank by the intake VVT mechanism, so that the EGR valve is stuck open. Even in the case, it is possible to suppress an excessive amount of EGR gas.

  Further, according to the above configuration, the intake valve timing of each EGR take-out bank can be variably controlled. Therefore, the intake air amount control means configured as described above individually sets the intake air amount in the EGR take-out bank. It is possible to control.

  Therefore, it is also possible to perform control so that the intake air amount is decreased only when the EGR valve is stuck open, particularly for the EGR take-out increase bank.

  As described above, when the intake amount of the EGR take-out increase bank is decreased by delaying the closing timing of the intake valve of the EGR take-out increase bank, the opening degree of the open EGR valve is set to open on the open side. As the degree increases, the closing timing of the intake valve of the EGR take-out increase bank may be delayed more.

  In this way, the intake air amount of the EGR take-out increase bank can be further reduced.

  In addition, when the intake valve timing of the cylinders in each EGR take-out bank is thus variably controlled for each bank, the intake amount in each bank can be individually controlled. Since there is no need to provide an individual throttle valve, a simple configuration including only a single throttle valve provided in the common intake passage as a throttle valve can be provided.

As described above, in the present invention, the intake amount of the EGR take-out increase bank is decreased when the open adhesion of the EGR valve is detected. Thereby, as above-mentioned, it can suppress that EGR gas amount becomes excessive, and can suppress that a combustion failure arises.

  On the other hand, in this case, since the torque of the EGR take-out increase bank decreases as the intake air amount decreases, a torque shortage may occur. When the degree of torque reduction is large, there is a possibility that torque for evacuation traveling cannot be obtained stably.

Therefore, in the present invention,
A second intake air amount control means for controlling an intake air amount flowing into a bank without EGR removal, which is a bank where a part of the exhaust gas is not taken out as EGR gas by any of the EGR passages;
A second failure time control means for increasing an intake air amount of the bank without EGR removal when compared to a normal time when the EGR valve is not openly fixed when the failure detection means detects that the EGR valve is stuck open;
May be further provided.

  By increasing the intake air amount in the bank without EGR removal, the torque generated by the combustion of the cylinders in the bank without EGR removal increases. Therefore, it is possible to suppress torque shortage when the EGR valve is stuck open.

  Moreover, since the EGR gas is not extracted from the exhaust gas discharged from the bank without EGR removal, even if the intake air amount of the bank without EGR removal is increased when the EGR valve is fixed open, the amount of EGR gas is excessive. There is no fear of becoming.

  In the above configuration, the second failure time control means may increase the intake air amount of the bank without EGR removal as the opening degree of the open and fixed EGR valve is an opening degree. .

  As described above, in the present invention, as the opening degree of the open EGR valve is the opening side, the control can be performed to further reduce the intake amount of the EGR take-out increase bank. Insufficient torque is more likely to occur.

  In this regard, according to the above configuration, the amount of intake air in the bank without EGR removal increases as the opening degree of the open and fixed EGR valve becomes the opening degree on the open side, so that torque shortage can be more reliably suppressed. Is possible.

In the above configuration, as a specific means for increasing the intake air amount of the bank without EGR removal when the EGR valve is stuck open,
An individual intake passage individually connected to each of the EGR non-removal banks;
The second intake air amount control means has an individual throttle valve provided in each individual intake passage,
The second failure time control means is configured such that when the failure detection means detects that the EGR valve is stuck open, the opening of the individual throttle valve provided in the individual intake passage connected to the bank without EGR removal is detected. May be set to an opening on the opening side of the normal time when the EGR valve is not fixed.

  In this way, the intake air amount of the bank without EGR removal can be increased by opening the individual throttle valve provided in the individual intake passage of the bank without EGR removal, so that when the EGR valve is stuck open, However, torque shortage can be suppressed.

As described above, when the intake air amount of the bank without EGR removal is increased by opening the individual throttle valve provided in the individual intake passage of the bank without EGR removal, the opening degree of the open EGR valve is fixed. The more the valve is opened, the more the opening of the individual throttle valve provided in the individual intake passage of the bank without EGR removal may be set to the opening side.

  By doing so, the amount of intake air in the bank without EGR removal can be further increased, so that torque shortage can be more reliably suppressed.

  In order to increase the intake air amount of the bank without EGR removal while decreasing the intake air amount of the EGR extraction increase bank when the open fixing of the EGR valve is detected, the intake air amount of the bank with EGR extraction and the EGR extraction without It is sufficient that the intake air amount of the bank can be controlled independently.

  Therefore, for example, the shared intake passage shared by the EGR non-takeout bank may be used even if the individual intake passage connected individually to each EGR non-takeout bank and the individual throttle valve provided thereon are not provided as described above. And a throttle valve provided in the supply intake passage, and the opening of the throttle valve may be on the open side.

In the above configuration, as a specific means for increasing the intake air amount of the bank without EGR removal when the EGR valve is stuck open,
The second intake air amount control means has a second intake VVT mechanism capable of variably controlling the intake valve timing of the cylinders of each of the EGR removal-free banks,
The second failure time control means is configured such that when the failure detection means detects that the EGR valve is stuck open, the EGR valve is stuck at the closing timing of the intake valve of the cylinder of the bank without EGR removal. You may make it advance ahead rather than the normal time.

  As described above, the intake air amount of the bank without EGR removal can be increased by advancing the valve closing timing of the intake valve of the cylinder of the bank without EGR removal by the second intake VVT mechanism, so that the EGR valve is opened. Even in the case of fixing, torque shortage can be suppressed.

  As described above, when the intake air amount of the bank without EGR removal is increased by advancing the closing timing of the intake valve of the bank without EGR removal, the opening degree of the open EGR valve is set to open on the open side. The higher the degree, the more the valve closing timing of the intake valve of the bank without EGR removal may be advanced.

  By doing so, the amount of intake air in the bank without EGR removal can be further increased, so that torque shortage can be more reliably suppressed.

  In order to increase the intake air amount of the bank without EGR extraction while decreasing the intake air amount of the EGR extraction increase bank when the open fixing of the EGR valve is detected, the intake air amount of the bank with EGR extraction and the EGR extraction without It is sufficient that the intake air amount of the bank can be controlled independently.

  Therefore, even if the configuration is not provided with the second intake VVT mechanism capable of individually variably controlling the intake valve timings of the cylinders in each EGR removal-free bank as described above, for example, the intake air of all the cylinders in the EGR removal-free bank A VVT mechanism that can variably control the valve timing may be provided, and the closing timings of the intake valves of all the cylinders in the EGR removal-free bank may be uniformly advanced.

Here, the failure time control means may perform fuel cut control on the cylinders of the EGR take-out increase bank when the failure detection means detects that the EGR valve is stuck open.

  In this case, if the intake / exhaust valve is normally opened and closed even during the fuel cut control in the EGR take-out increase bank, the EGR gas derived from the EGR take-out increase bank is mainly composed of air, not burned gas. . The EGR gas mainly containing air is hereinafter referred to as “air EGR gas”.

  Therefore, even if the EGR valve is fixed open and the EGR gas amount is excessive, the problem of combustion failure and insufficient torque due to the excessive amount of burned gas in the intake air is less likely to occur. There is a possibility that the amount of air inside becomes excessive. In that case, since the exhaust purification catalyst disposed in the exhaust system is exposed to excessively lean exhaust gas, the exhaust purification catalyst may be deteriorated.

  In this regard, in the present invention, as described above, when the EGR valve is stuck open, the intake control amount of the EGR take-out increase bank is reduced by the failure control means, so that the fuel cut control is performed. The air EGR gas derived from the increased EGR take-out bank can be prevented from flowing into the intake passage excessively.

  Therefore, it is possible to suitably suppress deterioration of the exhaust purification catalyst due to excessive lean intake air.

Here, in the case where fuel cut control is performed in the EGR take-out increase bank, the following configuration may be adopted in order to more reliably suppress the exhaust purification catalyst from being deteriorated by being exposed to excessively lean exhaust gas. it can. That is,
An individual intake passage individually connected to each bank with the EGR take-out,
The intake air amount control means has an individual throttle valve provided in each individual intake passage,
The EGR passage has an end on the intake passage side connected to at least an individual intake passage of each EGR take-out bank,
Each of the individual throttle valves is provided at a position upstream of the connection portion of the EGR passage in each of the individual intake passages.
When the failure detection means detects that the EGR valve is stuck open, the failure time control means performs fuel cut control on the cylinders of the EGR take-out increase bank among the EGR take-out banks, and The opening of the individual throttle valve provided in the individual intake passage connected to the EGR take-out increase bank may be set to an opening closer to the closing side than the normal time when the EGR valve is not fixed.

  According to the above configuration, the EGR passage causes at least the EGR gas taken out from the exhaust of the bank with EGR removal to flow into the individual intake passage of the bank with EGR removal.

  For banks other than the bank with EGR extraction, the EGR passage may be configured to allow EGR gas to flow into the individual intake passage, or EGR gas may be supplied to the common intake passage shared by the banks other than the bank with EGR extraction. You may be comprised so that it may flow in.

  In short, at least for the bank with EGR removal, it is sufficient that the EGR gas is introduced independently for each bank with EGR removal.

  When the EGR valve is stuck open, an EGR take-out bank (that is, part of the exhaust gas is taken out as EGR gas by the EGR passage provided with the open EGR valve). The individual throttle valve provided in the individual intake passage of the EGR take-out bank configured so as to be throttled is throttled.

  As a result, with respect to the EGR take-out increase bank, the pressure downstream of the individual throttle valve in the individual intake passage is changed to other banks other than the EGR take-out bank where the individual throttle valve is not throttled and banks other than the EGR take-out bank (no EGR take-out). It becomes lower than the individual intake passage of a bank etc.).

  According to the above configuration, the EGR passage is connected to the individual intake passage downstream of the individual throttle valve, so that the EGR gas flows more into the individual intake passage having a lower pressure downstream of the individual throttle valve. It becomes easy to do.

  Accordingly, when the EGR valve is stuck open, the individual throttle valve in the individual intake passage of the EGR take-out increase bank is throttled, so that the amount of EGR gas flowing into the EGR take-out increase bank increases, and the EGR to other banks is increased. Gas inflow is reduced.

  As a result, the EGR gas extracted from the exhaust gas discharged from the EGR extraction increase bank mainly flows again into the EGR extraction increase bank. As a result, the exhaust gas discharged from the EGR extraction increase bank is It will circulate mainly in the circulation path including the EGR fetch increase bank.

  In the above configuration, when the EGR valve is fixed open, fuel cut control is performed on the EGR take-out increase bank, so that the exhaust discharged from the EGR take-out increase bank is air.

  This air EGR gas circulates in the circulation path including the EGR take-out augmentation bank as described above. Therefore, the air EGR gas is prevented from flowing into a bank other than the EGR take-out increase bank or discharged directly from the EGR take-out increase bank to the exhaust system.

  As a result, excessively lean exhaust gas is prevented from flowing into the exhaust gas purification catalyst disposed in the exhaust system, so that fuel cut control is performed on the EGR take-out increase bank when the EGR valve open sticking is detected. Even in this case, the exhaust purification catalyst can be suitably suppressed from being deteriorated by being exposed to excessively lean exhaust gas.

  Here, the failure time control means determines the opening degree of the individual throttle valve provided in the individual intake passage connected to the EGR take-out increase bank as the opening degree of the opened and fixed EGR valve is the opening degree on the open side. The opening may be made closer to the closing side.

  By doing so, the air EGR gas derived from the EGR take-out increase bank can be circulated more reliably in the circulation path including the EGR take-out increase bank.

Further, in the above configuration, the EGR gas flowing through the EGR passage flows into a bank without EGR extraction (that is, a bank in which part of the exhaust gas is not extracted as EGR gas by any of the EGR passages). Having a shut-off device
When the failure detecting means detects that the EGR valve is stuck open, the failure time control means causes an EGR gas to flow into the bank without EGR removal from the EGR passage provided with the opened EGR valve. May be blocked by the blocking device.

  When each bank without EGR removal has an individual intake passage, the shut-off device may be configured to be able to block inflow of EGR gas from the EGR passage to the individual intake passage of each bank without EGR removal.

In addition, when a common intake passage with a bank without EGR removal is shared, the shutoff device may be configured to be able to shut off the inflow of EGR gas from the EGR passage to the common intake passage.

  In the above-described configuration, the air EGR gas flows through the EGR passage provided with the EGR valve that is firmly fixed.

  Therefore, the flow of EGR gas into the bank without EGR removal is suppressed by blocking the flow of EGR gas from the EGR passage provided with the open-fixed EGR valve to the intake passage of the bank without EGR removal. it can.

  As a result, the combustion gas in the bank without EGR removal is suppressed from being excessively lean, and it is possible to suitably suppress the deterioration of combustion caused by the air-fuel ratio shift and the deterioration of the exhaust purification catalyst.

Further, in the above configuration, the shut-off device is configured to be able to shut off the EGR gas flowing through the EGR passage from flowing into the individual intake passage connected to the EGR take-out bank,
When the failure detecting means detects that the EGR valve is stuck open, the failure time control means has the EGR take-out other than the EGR take-out increase bank from the EGR passage provided with the open-fixed EGR valve. The shut-off device may block the EGR gas from flowing into the bank.

  Thereby, since it is possible to suppress the inflow of the air EGR gas to the EGR take-out bank other than the EGR take-out increase bank, the air EGR gas derived from the EGR take-out increase bank is almost in the circulation path including the EGR take-out increase bank. Will be circulated.

  Therefore, it is possible to suitably suppress the deterioration of combustion and the deterioration of the exhaust purification catalyst due to the air-fuel ratio shift in the bank with EGR extraction other than the EGR extraction increase bank.

  Even in the above-described configuration in which the fuel cut control is performed on the EGR take-out increase bank when the EGR valve is stuck open, the intake air amount of the bank without EGR take-out is increased to increase the torque of the bank without EGR take-out. Thus, it is possible to secure a torque for more reliably performing the retreat travel when the EGR valve is stuck open. Specific means for increasing the intake air amount of the bank without EGR removal is as described above.

  In the present invention, one or more “banks with EGR removal” may be provided.

  When there are a plurality of banks with EGR take-out and an exhaust passage (individual exhaust passage) individually connected to each bank with EGR take-out is provided, the EGR passage is connected to an individual exhaust passage connected to each bank with EGR take-out. Each can be configured as a plurality of passages that individually connect the intake passages of the internal combustion engine.

  In this case, the EGR valve can be configured as a plurality of EGR valves provided in each of a plurality of EGR passages.

  Further, in such a configuration, the EGR take-out bank connected to the individual exhaust passage to which the EGR passage provided with the open-fixed EGR valve among the plurality of EGR passages is connected is provided with the EGR take-out described above. It will be an increase bank.

  Therefore, the failure time control means controls to reduce the intake air amount of the EGR take-out bank to which the individual exhaust passage to which the EGR passage provided with the open and fixed EGR valve is connected is connected.

  Further, when there are a plurality of banks with EGR removal, and an exhaust passage (shared exhaust passage) shared by at least some of the plurality of banks with EGR removal is provided, the EGR passage is connected to the common exhaust passage. Also, it can be configured as a passage connecting the intake passage of the internal combustion engine.

  In such a configuration, the shared exhaust passage is configured as a single shared exhaust passage shared by all the banks with EGR extraction, and the EGR passage is simply connected to the single shared exhaust passage and the intake passage. A single EGR passage may be configured.

  In this case, the EGR valve can be configured as a single EGR valve provided in a single system EGR passage.

  Alternatively, the bank with EGR removal is divided into a plurality of groups, and each group has a shared exhaust passage shared by the banks with EGR removal belonging to the group, and the common exhaust passage is used as a shared exhaust passage of a plurality of systems corresponding to the plurality of groups. The EGR passage may be configured as a plurality of EGR passages that individually connect each of the plurality of shared exhaust passages and the intake passage.

  In this case, the EGR valve can be configured as a plurality of EGR valves provided in each of a plurality of EGR passages.

  As described above, when the EGR passage is configured so as to connect the common exhaust passage and the intake passage, the common exhaust passage connected to the EGR passage provided with the EGR valve that is particularly open and fixed is connected to the EGR passage. All of the plurality of shared banks with EGR fetch are the above-described EGR fetch augmentation banks.

  Therefore, the failure time control means may perform control to reduce the intake air amount of all EGR take-out banks that share the common exhaust passage to which the EGR passage provided with the open-fixed EGR valve is connected. .

  In addition, the EGR passage connected to each of the plurality of individual exhaust passages or the EGR passage connected to each of the plurality of shared exhaust passages associated with the plurality of groups merges in the middle, and the EGR after joining The EGR passage may be configured such that the passage is connected to the intake passage. In this way, when the merging portion exists in the middle of the EGR passage, there are cases where the EGR valve is provided on the exhaust passage side with respect to the merging portion and when the merging portion is provided on the intake passage side with respect to the merging portion. It is done.

  When the EGR valve is provided in the EGR passage (referred to as the pre-merging EGR passage) closer to the exhaust passage than the merging portion, the EGR valve is fixedly connected to the pre-merged EGR passage provided with the opened and fixed EGR valve. Derived from the exhaust from the bank with EGR removal connected to the individual exhaust passage, or the bank with EGR removal sharing the common exhaust passage to which the pre-merging EGR passage provided with the open and fixed EGR valve is connected This may affect the EGR gas amount control, and the EGR gas amount may be excessive.

Therefore, an EGR take-out bank connected to the individual exhaust passage connected to the pre-merging EGR passage provided with the open-fixed EGR valve, or the pre-merging EGR passage provided with the open-fixed EGR valve was connected. The bank with EGR extraction that shares the common exhaust passage is the target of intake air amount reduction control by the failure time control means of the present invention as an EGR extraction increase bank.

  Further, when the EGR valve is provided in the EGR passage (referred to as the EGR passage after merging) on the intake passage side from the merging portion, the EGR valve is fixedly attached after the merging EGR passage provided with the opened and fixed EGR valve. All EGR take-out banks connected to the individual exhaust passages connected to the EGR passages to be joined to the EGR passages, or the shared exhaust to which the EGR passages joined to the EGR passages after the joined EGR passages are provided. This affects the EGR gas amount control derived from the exhaust from all the EGR take-out banks sharing the passage, and the EGR gas amount may be excessive.

  Accordingly, the bank with EGR removal connected to the individual exhaust passage connected to the EGR passage that joins the EGR passage after the merging where the open and fixed EGR valve is provided, or after the merging that the EGR valve that is attached and fixed is provided. The bank with EGR extraction that shares the common exhaust passage to which the EGR passage that merges with the EGR passage is connected becomes the target of the intake amount reduction control by the failure time control means of the present invention as the EGR extraction increase bank.

  According to the present invention, even when the EGR valve provided in the EGR passage is stuck open, it is possible to suppress an excessive amount of EGR gas and to secure a sufficient torque for the retreat travel.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the component parts described in the present embodiment are not intended to limit the technical scope of the invention only to those unless otherwise specified.

  FIG. 1 is a conceptual diagram schematically showing a schematic configuration of an internal combustion engine to which an EGR device for an internal combustion engine according to the present embodiment is applied and its intake system and exhaust system.

  In FIG. 1, the engine 1 is a 6-cylinder V-type engine in which a first bank 2 including three cylinders 4 and a second bank 3 including three cylinders 5 are arranged in a V shape. A first individual intake passage 6 that communicates with each cylinder 4 of the first bank 2 is connected to the first bank 2. The second bank 3 is connected to a second individual intake passage 7 that communicates with each cylinder 5 of the second bank 3. The first individual intake passage 6 and the second individual intake passage 7 gather in the common intake passage 8 upstream.

  A first individual exhaust passage 10 communicating with each cylinder 4 of the first bank 2 is connected to the first bank 2.

  A second individual exhaust passage 9 that communicates with each cylinder 5 of the second bank 3 is connected to the second bank 3.

  The first individual exhaust passage 10 and the second individual exhaust passage 9 gather in the common exhaust passage 11 downstream.

  The first bank 2 is provided with a first intake VVT mechanism 16 that can change the valve timing of an intake valve (not shown) of each cylinder 4.

  The second bank 3 is provided with a second intake VVT mechanism 15 that can change the valve timing of the intake valve (not shown) of each cylinder 5.

  The first individual exhaust passage 10 and the common intake passage 8 communicate with each other through an EGR passage 12. Part of the exhaust discharged from the first bank 2 is taken out by the EGR passage 12 and flows into the common intake passage 8 as EGR gas through the EGR passage 12.

  An EGR valve 13 that adjusts the flow rate of the EGR gas flowing through the EGR passage 12 is provided in the middle of the EGR passage 12. An EGR valve opening sensor 17 that measures the opening of the EGR valve 13 is provided. A throttle valve 14 is provided on the upstream side of the common intake passage 8 where the EGR passage 12 is connected.

  The first bank 2 is a bank in which at least a part of the exhaust gas discharged from the first bank 2 is taken out by the EGR passage 12 and flows into the common intake passage 8 as EGR gas. Corresponds to “bank”.

  On the other hand, the second bank 3 is a bank in which a part of the exhaust discharged from the second bank 3 is not taken out as EGR gas by the EGR passage 12, and corresponds to the “bank without EGR removal” in the present invention.

  The EGR valve opening sensor 17 and other various sensors are connected to the ECU 18, and the measurement data is input to the ECU 18. Further, the EGR valve 13, the throttle valve 14, the first intake VVT mechanism 16, the second intake VVT mechanism 15 and other various devices are connected to the ECU 18, and the operation of these devices is controlled by the ECU 18. Yes.

  The ECU 18 is a computer that controls the operation of the engine 1 and has a known configuration such as a ROM that stores various control programs, a CPU that executes the control programs, and a RAM that temporarily stores measurement data.

  The ECU 18 grasps the operating state of the engine 1 such as the load and the rotational speed based on measurement data input from various sensors, and controls signals to various devices such as the EGR valve 13 and the throttle valve 14 according to the grasped operating state. Is sent out.

  Normally, the opening degree of the EGR valve 13 is controlled by the ECU 18 to a target opening degree that is predetermined according to the operating state of the engine 1. The target opening of the EGR valve 13 is set so that an amount of EGR gas that is preliminarily adapted to satisfy the requirements of the engine 1 such as the emission performance and the fuel consumption performance flows into the first bank 2 and the second bank 3. 1 is determined according to the operating state of 1 and stored in the ROM of the ECU 18.

  However, when the EGR valve 13 is stuck open due to troubles such as failure of the actuator that drives the EGR valve 13 or accumulation of foreign matter (sticking in the opened state), the opening degree of the EGR valve 13 is the opening degree at the time of sticking open. It becomes impossible to control the amount of EGR gas according to the operating state of the engine 1.

  In that case, in particular, in an operating state in which the opening degree at the time of open fixation is larger than the target opening degree, the amount of EGR gas in the intake air becomes excessive, which may cause a combustion failure.

  That is, when the EGR valve 13 is fixed open, the first bank 2 corresponds to the “EGR take-out increase bank” in the description of the present invention described above.

  Therefore, in the EGR device of the present embodiment, when it is detected that the EGR valve 13 is stuck open, the EGR valve 13 opens the closing timing of the intake valve of the cylinder 4 of the first bank 2 which is the EGR take-out increase bank. The first intake VVT mechanism 16 is set so that the valve closing timing is delayed as shown in FIG. 2 (B1) with respect to the valve closing timing shown in FIG. I decided to control it.

  By retarding the closing timing of the intake valve of the first bank 2, the intake amount of the first bank 2 decreases. Therefore, the amount of exhaust discharged from the first bank 2 is also reduced, and the amount of exhaust taken out as EGR gas from the first individual exhaust passage 10 through the EGR passage 12 is also reduced.

  As a result, even when the EGR valve 13 is open and fixed, it is possible to prevent the amount of EGR gas flowing into the common intake passage 8 through the EGR passage 12 from becoming excessively larger than usual. .

  Thereby, even if the EGR valve 13 is fixed open, it is possible to suppress the intake EGR gas amount from being excessive, and to suppress the occurrence of combustion failure.

  Depending on whether or not it is detected that the EGR valve 13 is stuck open, the closing timing of the intake valve of the first bank 2 is divided into two types: a normal timing and a timing delayed from that. Although it may be switched to any one of the valve closing timings, the valve closing timings of the intake valves of the first bank 2 may be more finely controlled in accordance with the state of the EGR valve 13 being stuck open.

  For example, as shown in FIG. 3, the closing timing of the intake valve of the first bank 2 (EGR take-out increase bank) becomes larger as the opening degree of the EGR valve 13 at the time of open fixation is the opening degree side opening degree (large opening degree). May be delayed more.

  At this time, as shown in FIG. 3, the closing timing of the intake valve of the first bank 2 may be continuously changed according to the fixing opening degree of the EGR valve 13, or may be changed stepwise. May be.

  In this way, the amount of exhaust discharged from the first bank 2 can be reduced by an optimum amount according to the degree of opening of the EGR valve 13, so that combustion failure occurs when the EGR valve 13 is stuck open. Can be more reliably suppressed.

  Further, the opening degree of the EGR valve 13 at the time of open fixing is compared with the target opening degree, and only when the opening degree at the time of opening fixing is on the open side from the target opening degree, the first bank 2 Control may be performed to retard the closing timing of the intake valve.

  This is because if the opening at the time of open fixation is closer to the target opening, even if the EGR valve 13 is open and fixed, the amount of EGR gas is excessive and there is a low possibility of causing combustion failure. is there.

  By the way, when the open adhering of the EGR valve 13 is detected in this way, if the intake amount of the first bank 2 is decreased, the torque of the first bank 2 decreases. If the degree of torque reduction is large, there is a risk that sufficient torque for performing retreat travel without any problem cannot be secured.

Therefore, in the EGR device of the present embodiment, when the open fixing of the EGR valve 13 is detected, control is performed to retard the closing timing of the intake valve of the first bank 2 that is the EGR take-out increase bank as described above, Further, the closing timing of the intake valve of the second bank 3 which is a bank without EGR removal is illustrated with respect to the closing timing as shown in FIG. 2 (A2) at the normal time when the EGR valve 13 is not fixed open. 2 (B2), the second intake VVT mechanism 15 is controlled so that the advanced valve closing timing is reached.

  By advancing the closing timing of the intake valve of the second bank 3, the intake amount of the second bank 3 increases. In response to this, the torque of the second bank 3 can be increased by increasing the fuel injection amount of the second bank 3.

  As a result, even when the control for reducing the intake air amount of the first bank 2 is executed when the EGR valve 13 is detected to be stuck firmly, it is possible to prevent the torque from becoming insufficient and to secure sufficient torque for the retreat travel. It becomes possible.

  Note that, similarly to the case where the closing timing of the intake valve of the first bank 2 is retarded, the intake valve of the second bank 3 is determined depending on whether or not the EGR valve 13 is detected to be stuck open. The valve closing timing may be switched to one of two types of valve closing timings, a normal timing and a timing advanced from the normal timing, but depending on the situation of the EGR valve 13 being stuck open, The valve closing timing of the intake valve of the second bank 3 may be finely controlled.

  For example, as shown in FIG. 3, the closing timing of the intake valve of the second bank 3 (the bank without EGR removal) becomes larger as the opening degree of the EGR valve 13 at the time of open fixing is the opening degree side (large opening degree). May be further advanced.

  At this time, as shown in FIG. 3, the closing timing of the intake valve of the second bank 3 may be continuously changed according to the fixing opening degree of the EGR valve 13, or may be changed stepwise. May be.

  In this way, the torque of the second bank 3 can be increased according to the fixing opening degree of the EGR valve 13, so that it is possible to more reliably suppress the torque shortage when the EGR valve 13 is fixed open. Become.

  The control flow of the present embodiment described above will be described with reference to FIG. The routine shown by the flowchart of FIG. 4 is periodically executed by the ECU 18 while the engine 1 is operating.

  In step S101, the ECU 18 determines whether or not the EGR valve 13 is stuck open. In this embodiment, the actual opening degree of the EGR valve 13 measured by the EGR valve opening degree sensor 17 is compared with the target opening degree set by the ECU 18, and the actual opening degree with respect to the change in the target opening degree. Is detected, it is determined that the EGR valve 13 is stuck open.

  If it is determined in step S101 that the EGR valve 13 is open and stuck (Yes), the ECU 18 proceeds to step S102. On the other hand, when it is determined in step S101 that the EGR valve 13 is not open and fixed (No), the ECU 18 proceeds to step S103.

  In step S102, the ECU 18 determines whether or not the fixed opening degree of the EGR valve 13 is on the opening side with respect to the target opening degree.

  If it is determined in step S102 that the fixed opening is on the opening side of the target opening (Yes), the ECU 18 proceeds to step S104. On the other hand, if it is determined in step S102 that the fixed opening is not on the opening side of the target opening (No), the ECU 18 proceeds to step S103.

  In step S103, the ECU 18 executes normal processing for the intake valve timing control of the first bank 2 and the second bank 3. That is, the closing timing of the intake valves of the first bank 2 and the second bank 3 is set to a base map value that is predetermined according to the operating state of the engine 1. In this case, as shown in FIGS. 2A1 and 2A2, the closing timing of the intake valve of the first bank 2 and the closing timing of the intake valve of the second bank 3 are set to the same timing.

  In step S104, the ECU 18 executes a correction process for the intake valve timing control of the first bank 2 and the second bank 3. That is, the first intake VVT mechanism 16 is controlled so that the closing timing of the intake valves of the first bank 2 is delayed from the base map value, and the closing timing of the intake valves of the second bank 3 is set. The second intake VVT mechanism 15 is controlled so that the timing is advanced from the base map value.

  By executing the above routine, even when the EGR valve 13 is stuck open and the sticking opening is the opening on the opening side from the target opening, it is suppressed that the amount of EGR gas is excessive, and combustion It becomes possible to suppress the occurrence of defects and to secure a sufficient torque for retreat travel.

  In the present embodiment, the first intake VVT mechanism 16 that controls the intake air amount of the first bank 2 that is the bank with EGR extraction corresponds to the intake air amount control means, in particular, the intake VVT mechanism in the present invention.

  The ECU 18 that executes step S101 and determines whether or not the EGR valve 13 is stuck open corresponds to the failure detection means in the present invention.

  In step S103, the ECU 18 that performs the process of retarding the closing timing of the intake valves of the first bank 2 from the base map value corresponds to the failure time control means in the present invention.

  The second intake VVT mechanism 15 that controls the intake air amount of the second bank 3 that is a bank without EGR removal corresponds to the second intake air amount control means, particularly the second intake VVT mechanism in the present invention.

  In step S103, the ECU 18 that performs the process of advancing the closing timing of the intake valve of the second bank 3 more than the base map value corresponds to the second failure time control means in the present invention.

  Next, a second embodiment of the present invention will be described. FIG. 5 is a conceptual diagram schematically showing a schematic configuration of an internal combustion engine to which the EGR device for an internal combustion engine according to the present embodiment is applied, and its intake system and exhaust system.

  In FIG. 5, the engine 10 includes a first bank 31 including three cylinders 21, a second bank 32 including three cylinders 22, a third bank 33 including three cylinders 23, and three cylinders 24. And a fourth bank 34.

  A first individual intake passage 41 that communicates with the cylinders 21 of the first bank 31 is connected to the first bank 31.

  The second bank 32 is connected to a second individual intake passage 42 that communicates with the cylinders 22 of the second bank 32.

  The third bank 33 and the fourth bank 34 have a first shared intake passage 430 that communicates with the cylinder 23 of the third bank 33 and the cylinder 24 of the fourth bank 34 and is shared by the third bank 33 and the fourth bank 34. It is connected.

  The first individual intake passage 41 is provided with a first individual throttle valve 61 that adjusts the amount of intake air flowing through the first individual intake passage 41.

  The second individual intake passage 42 is provided with a second individual throttle valve 62 that adjusts the amount of intake air flowing through the second individual intake passage 42.

  The first shared intake passage 430 is provided with a shared throttle valve 630 that adjusts the amount of intake air flowing through the first shared intake passage 430.

  The first individual intake passage 41, the second individual intake passage 42, and the first shared intake passage 430 are gathered in a second shared intake passage 500 that is shared by all banks upstream.

  A first individual exhaust passage 71 that communicates with the cylinders 21 of the first bank 31 is connected to the first bank 31.

  A second individual exhaust passage 72 that communicates with the cylinders 22 of the second bank 32 is connected to the second bank 32.

  A third individual exhaust passage 73 communicating with the cylinder 23 of the third bank 33 is connected to the third bank 33.

  A fourth individual exhaust passage 74 communicating with the cylinder 24 of the fourth bank 34 is connected to the fourth bank 34.

  The first individual exhaust passage 71 to the fourth individual exhaust passage 74 are gathered in a common exhaust passage 80 shared by all banks downstream.

  The first individual exhaust passage 71 and the second shared intake passage 500 are communicated with each other by a first EGR passage 91. A part of the exhaust discharged from the first bank 31 is taken out by the first EGR passage 91 and flows into the second shared intake passage 500 through the first EGR passage 91 as EGR gas.

  The second individual exhaust passage 72 and the second shared intake passage 500 are communicated with each other by a second EGR passage 92. A part of the exhaust discharged from the second bank 32 is taken out by the second EGR passage 92 and flows into the second shared intake passage 500 through the second EGR passage 92 as EGR gas.

  A first EGR valve 101 that adjusts the flow rate of EGR gas flowing through the first EGR passage 91 is provided in the middle of the first EGR passage 91. Further, a first EGR valve opening sensor 111 that measures the opening of the first EGR valve 101 is provided.

  A second EGR valve 102 that adjusts the flow rate of EGR gas flowing through the second EGR passage 92 is provided in the middle of the second EGR passage 92. Moreover, the 2nd EGR valve opening degree sensor 112 which measures the opening degree of the 2nd EGR valve 102 is provided.

  In the first bank 31 and the second bank 32, at least a part of the exhaust gas discharged from these banks is taken out by the first EGR passage 91 or the second EGR passage 92 and flows into the second shared intake passage 500 as EGR gas. This is a bank and corresponds to the “bank with EGR extraction” in the present invention.

  On the other hand, the third bank 33 and the fourth bank 34 are banks in which part of the exhaust gas discharged from these banks is not taken out by either the first EGR passage 91 or the second EGR passage 92. Corresponds to “no take out bank”.

  The first EGR valve opening sensor 111, the second EGR valve opening sensor 112, and other various sensors are connected to the ECU 120, and the measurement data is input to the ECU 120.

  Further, the ECU 120 is connected to the first EGR valve 101, the second EGR valve 102, the first individual throttle valve 61, the second individual throttle valve 62, the common throttle valve 630, and other various devices, and the ECU 120 operates these devices. Is to be controlled.

  The ECU 120 is a computer that controls the operation of the engine 1 and has a known configuration such as a ROM that stores various control programs, a CPU that executes the control programs, and a RAM that temporarily stores measurement data. ECU120 grasps | ascertains driving conditions, such as a load of the engine 1, and rotation speed, based on the measurement data input from various sensors, and sends a control signal to the said various apparatus according to the grasped driving | running state.

  Problems that may occur when the first EGR valve 101 or the second EGR valve 102 is stuck open are as described in the first embodiment. In this embodiment, the control performed when the first EGR valve 101 is stuck open in the engine EGR apparatus having the above-described configuration will be described.

  When the first EGR valve 101 is stuck open and the sticking opening is larger than the target opening set by the ECU 120 according to the operating conditions of the engine 1, the intake EGR gas amount is excessive. There is a risk of poor combustion.

  That is, when the first EGR valve 101 is fixed open, the first bank 31 corresponds to the “EGR take-out increase bank” in the description of the present invention.

  On the other hand, since it is assumed here that the second EGR valve 102 is not open-fixed, the second bank 32 is the “bank with EGR extraction” in the present invention, but not the “EGR extraction increase bank”.

  In this embodiment, when it is detected that the first EGR valve 101 is fixed open, the first individual throttle valve 61 provided in the first individual intake passage 41 connected to the first bank 31 that is an EGR take-out increase bank is provided. The opening degree is changed to an opening degree closer to the closing side than the normal time when the first EGR valve 101 is not open and fixed.

  By doing so, the amount of intake air flowing into the first bank 31 decreases. Therefore, the amount of exhaust gas discharged from the first bank 31 is also reduced, and the amount of exhaust gas taken out as EGR gas from the first individual exhaust passage 71 by the first EGR passage 91 is also reduced.

As a result, even when the first EGR valve 101 is in an open and fixed state, the amount of EGR gas flowing into the second shared intake passage 500 through the first EGR passage 91 should not be excessively larger than normal. Is possible.

  Thereby, even if the first EGR valve 101 is opened and fixed, it is possible to suppress an excessive amount of intake EGR gas, and to suppress the occurrence of poor combustion.

  As in the first embodiment, the opening degree of the first individual throttle valve 61 is set to the normal opening degree and the closing side of the first individual throttle valve 61 depending on whether or not it is detected that the first EGR valve 101 is opened and fixed. The opening degree may be switched to one of two opening degrees, a predetermined opening degree, but the opening degree of the first individual throttle valve 61 is controlled more finely according to the fixing opening degree of the first EGR valve 101. Also good.

  For example, as shown in FIG. 6, the opening degree of the first individual throttle valve 61 is controlled to the closing side opening degree as the fixing opening degree of the first EGR valve 101 is the opening side opening degree (large opening degree). You may do it.

  At this time, as shown in FIG. 6, the opening degree of the first individual throttle valve 61 may be continuously changed according to the fixing opening degree of the first EGR valve 101, or may be changed stepwise. Also good.

  In this way, the amount of exhaust exhausted from the first bank 31 can be reduced by an optimum amount according to the opening degree of the first EGR valve 101, so that when the first EGR valve 101 is stuck open, It becomes possible to suppress the combustion failure more reliably.

  Further, the fixed opening degree of the first EGR valve 101 at the time of open fixation and the target opening set by the ECU 120 according to the operating condition of the engine 1 are compared, and the fixed opening degree is larger than the target opening degree. Only when it is on the side, control may be performed to change the opening of the first individual throttle valve 61 to the closed side.

  As described above, when the open adhesion of the first EGR valve 101 is detected, if the intake air amount of the first bank 31 is decreased, the torque of the first bank 31 is decreased. If the degree of torque reduction is large, there is a risk that sufficient torque for performing retreat travel without any problem cannot be secured.

  Therefore, in the EGR device of the present embodiment, when the first EGR valve 101 is detected as being stuck open, the opening degree of the individual throttle valve 61 of the first bank 31 that is the EGR take-out increase bank is set to the closing side opening degree as described above. In addition, the individual throttle valves of banks other than the EGR take-out increase bank, that is, the second individual throttle valve 62 of the second bank 32 that is an EGR take-out bank but is not an EGR take-out increase bank, and EGR Changing the opening degree of the shared throttle valve 630 of the third bank 33 and the fourth bank 34, which is a bank without removal, to an opening side that is more open than the normal opening degree where the first EGR valve 101 is not openly fixed. It was.

  As a result, the intake air amount in the second bank 32 to the fourth bank 34 increases. Accordingly, the torque of the second bank 32 to the fourth bank 34 can be increased by increasing the fuel injection amount of the second bank 32 to the fourth bank 34 from the normal time.

  As a result, even if control is performed to reduce the intake air amount of the first bank 31 when the first EGR valve 101 is detected to be stuck open, torque shortage can be suppressed and sufficient torque for retreat travel can be secured. Is possible.

Note that, similarly to the case where the opening degree of the first individual throttle valve 61 of the first bank 31 is set to the closed side, the second individual throttle valve 61 is determined depending on whether or not the first EGR valve 101 is detected to be open and stuck. Although the opening degree of the throttle valve 62 and the common throttle valve 630 may be switched to one of two opening degrees, a normal opening degree and an opening degree on the opening side thereof, the first EGR valve 101 The opening degree of the second individual throttle valve 62 and the common throttle valve 630 may be controlled more finely according to the state of the open sticking.

  For example, as shown in FIG. 6, the opening degree of the second individual throttle valve 62 and the common throttle valve 630 is further increased as the opening degree of the first EGR valve 101 at the time of the open fixing is the opening side opening degree (large opening degree). The opening may be on the opening side.

  At this time, as shown in FIG. 6, the opening degree of the second individual throttle valve 62 and the common throttle valve 630 may be continuously changed according to the fixing opening degree of the first EGR valve 101, or stepwise. It may be changed.

  In this way, the torque of the second bank 32 to the fourth bank 34 can be increased in accordance with the opening degree of the first EGR valve 101, so that the torque shortage during the open fixing of the first EGR valve 101 can be ensured. Can be suppressed. Although FIG. 6 shows an example in which the opening degree of the second individual throttle valve 62 and the opening degree of the common throttle valve 630 are equal, the opening degrees may be different.

  The control flow of the present embodiment described above will be described with reference to FIG. The routine shown by the flowchart of FIG. 7 is periodically executed by the ECU 120 while the engine 1 is operating.

  In step S <b> 201, the ECU 120 determines whether at least one of the first EGR valve 101 and the second EGR valve 102 is openly fixed. In this embodiment, the actual opening degree of the first EGR valve 101 measured by the first EGR valve opening degree sensor 111 is compared with the target opening degree set by the ECU 120, and the actual opening degree is compared with the change in the target opening degree. When it is detected that the opening degree has not changed, it is determined that the first EGR valve 101 is stuck open. Similarly, the second EGR valve 102 is also checked for the presence of open adhesion.

  If it is determined in step S201 that at least one of the first EGR valve 101 or the second EGR valve 102 is stuck open, the ECU 120 proceeds to step S202. On the other hand, when it is determined in step S201 that neither the first EGR valve 101 nor the second EGR valve 102 is open and stuck, the ECU 120 proceeds to step S203.

  In step S202, the ECU 120 determines whether the fixed opening degree of the EGR valve determined to be opened and fixed in step S201 is on the opening side with respect to the target opening degree.

  If it is determined in step S202 that the fixed opening degree of the opened EGR valve is not on the open side with respect to the target opening degree, the ECU 120 proceeds to step S203.

  In step S <b> 203, the ECU 120 executes normal processing for opening control of the first individual throttle valve 61, the second individual throttle valve 62, and the common throttle valve 630. That is, the opening degrees of the first individual throttle valve 61, the second individual throttle valve 62, and the common throttle valve 630 are set to base map values that are determined in advance according to the operating state of the engine 1.

  In step S202, if it is determined that the EGR valve 101 that is open and stuck includes at least the first EGR valve 101, and it is determined that the sticking opening degree of the first EGR valve 101 is more open than the target opening degree, the ECU 120 performs step. The process proceeds to S204.

  In step S204, the ECU 120 executes a correction process for the opening control of the first individual throttle valve 61, the second individual throttle valve 62, and the common throttle valve 630. That is, the opening degree of the first individual throttle valve 61 is controlled to be closer to the closing side than the base map value, and the opening degree of the second individual throttle valve 62 and the common throttle valve 630 is opened to the opening side of the base map value. Control the opening.

  As a result, the amount of exhaust discharged from the first bank 31 that is an EGR extraction increasing bank decreases, and the amount of exhaust extracted from the first individual exhaust passage 71 by the first EGR passage 91 decreases, so that the first EGR valve 101 Even if the opening is fixed at an opening on the opening side of the target opening, it is possible to suppress an excessive amount of intake EGR gas.

  Further, the intake air amount of the second bank 32 which is an EGR extraction bank but not the EGR extraction increase bank, the third bank 33 and the fourth bank 34 which are not EGR extraction banks, and the torque of these banks increases. Therefore, it is possible to compensate for the torque shortage accompanying the decrease in the intake air amount of the first bank 31.

  In step S202, if it is determined that the EGR valve that is open and fixed includes at least the second EGR valve 102, and it is determined that the fixed opening of the second EGR valve 102 is on the opening side with respect to the target opening, the ECU 120 performs step. The process proceeds to S205.

  In step S205, the ECU 120 executes a correction process for the opening control of the first individual throttle valve 61, the second individual throttle valve 62, and the common throttle valve 630. In other words, the opening degree of the second individual throttle valve 62 is controlled to the opening side closer to the closing side than the base map value, and the opening degree of the first individual throttle valve 61 and the common throttle valve 630 is opened to the opening side of the base map value. Control the opening.

  As a result, the amount of exhaust discharged from the second bank 32, which is an EGR extraction increasing bank, decreases, and the amount of exhaust extracted from the second individual exhaust passage 72 by the second EGR passage 92 decreases, so that the second EGR valve 102 Even if the opening is fixed at an opening on the opening side of the target opening, it is possible to suppress an excessive amount of intake EGR gas.

  Further, the intake air amount of the first bank 31 that is an EGR extraction bank but not the EGR extraction increase bank, the third bank 33 and the fourth bank 34 that are not the EGR extraction bank, and the torque of these banks increases. Therefore, it is possible to compensate for the torque shortage accompanying the decrease in the intake air amount of the second bank 32.

  In step S202, both the first EGR valve 101 and the second EGR valve 102 are stuck open, and the sticking opening degree of the first EGR valve 101 and the sticking opening degree of the second EGR valve 102 are on the opening side with respect to the target opening degree. If it is determined that there is, the ECU 120 proceeds to step S206.

  In step S <b> 206, the ECU 120 executes a correction process for opening control of the first individual throttle valve 61, the second individual throttle valve 62, and the common throttle valve 630. In other words, the opening degree of the first individual throttle valve 61 and the opening degree of the second individual throttle valve 62 are controlled to the opening degree closer to the closing side than the base map value, and the opening degree of the common throttle valve 630 is made to be lower than the base map value. The opening is controlled to the opening side.

As a result, the amount of exhaust discharged from the first bank 31 and the second bank 32, which are EGR extraction increasing banks, decreases, and the amount of exhaust extracted from the first individual exhaust passage 71 by the first EGR passage 91 is also the second EGR passage. Since the amount of exhaust gas taken out from the second individual exhaust passage 72 by 92 is also reduced, even if the first EGR valve 101 and the second EGR valve 102 are open and fixed at an opening degree that is more open than the target opening degree. It is possible to suppress the intake EGR gas from becoming excessive.

  Further, since the intake air amount of the third bank 33 and the fourth bank 34, which are the banks without EGR removal, is increased and the torque of these banks is increased, the intake air amount of the first bank 31 and the second bank 32 is decreased. Torque shortage can be compensated.

  By executing the above routine, the EGR gas amount becomes excessive even when the first EGR valve 101 and the second EGR valve 102 are opened and fixed, and the fixed opening is an opening closer to the opening than the target opening. As a result, it is possible to suppress the occurrence of defective combustion and to secure a sufficient torque for retreat travel.

  In the present embodiment, the first individual intake passage 41 connected to the first bank 31 that is an EGR take-out bank and the second individual intake passage 42 connected to the second bank 32 are the individual intake passage in the present invention. It corresponds to.

  The first individual throttle valve 61 provided in the first individual intake passage 41 and the second individual throttle valve 62 provided in the second individual intake passage 42 correspond to the individual throttle valve in the present invention.

  The ECU 120 that executes step S201 and determines whether or not there is one that is openly fixed to the first EGR valve 101 or the second EGR valve 102 corresponds to the failure detection means in the present invention.

  In step S204, step S205, or step S206, the ECU 120 that performs processing for controlling the opening degree of the first individual throttle valve 61 and / or the second individual throttle valve 62 to be closer to the closing side than the base map value is a failure in the present invention. It corresponds to the control means.

  The shared throttle valve 630 provided in the first shared intake passage 430 shared by the third bank 33 and the fourth bank 34, which are banks without EGR removal, corresponds to the second intake amount control means in the present invention.

  The ECU 120 that performs the process of controlling the opening of the common throttle valve 630 to the opening side from the base map value in step S203, step S204, step S205, or step S206 corresponds to the second failure time control means in the present invention.

  In addition, in step S204, step S205, or step S206, the ECU 120 that performs processing for controlling the individual throttle valve of the bank that is in the bank with EGR extraction but not in the EGR extraction increase bank to be more open than the base map value is also included in the present invention. It may be considered that this corresponds to the second failure time control means.

  Next, Embodiment 3 of the present invention will be described. FIG. 8 is a conceptual diagram schematically showing a schematic configuration of an internal combustion engine to which the EGR device for an internal combustion engine according to the present embodiment is applied and its intake system and exhaust system.

In FIG. 8, the engine 1 is a 6-cylinder V-type engine in which a first bank 31 including three cylinders 21 and a second bank 32 including three cylinders 22 are arranged in a V shape. A first individual intake passage 41 that communicates with each cylinder 21 of the first bank 31 is connected to the first bank 31. The second bank 32 is connected to a second individual intake passage 42 that communicates with each cylinder 22 of the second bank 32. The first individual intake passage 41 and the second individual intake passage 42 gather in the common intake passage 50 upstream.

  A first individual exhaust passage 71 that communicates with each cylinder 21 of the first bank 31 is connected to the first bank 31.

  A second individual exhaust passage 72 that communicates with each cylinder 22 of the second bank 32 is connected to the second bank 32.

  The first individual exhaust passage 71 and the second individual exhaust passage 72 are gathered in the common exhaust passage 80 downstream.

  A first front catalyst 141 is disposed in the first individual exhaust passage 71. A second front catalyst 142 is disposed in the second individual exhaust passage 72. An underfloor catalyst 150 is disposed in the shared exhaust passage 80.

  An EGR passage 91 is connected to the first individual exhaust passage 71 on the downstream side of the first pre-stage catalyst 141. The EGR passage 91 branches into a first branch passage 911 and a second branch passage 912 at a branch portion 910 on the way, the first branch passage 911 is connected to the first individual intake passage 41, and the second branch passage 912 is a second individual passage. It is connected to the intake passage 42.

  An EGR valve 91 that adjusts the flow rate of the EGR gas flowing through the EGR passage 91 is provided in the EGR passage 91 on the upstream side of the branch portion 910. An EGR valve opening sensor 111 that measures the opening of the EGR valve 101 is also provided.

  Further, a shutoff valve 132 capable of blocking the flow of EGR gas in the second branch passage 912 into the second individual intake passage 42 is provided in the middle of the second branch passage 912.

  A part of the exhaust gas discharged from the first bank 31 is taken out by the EGR passage 91, passes through the EGR passage 91, the first branch passage 911, and the second branch passage 912 as EGR gas. It flows into the individual intake passage 42.

  A first individual throttle valve 61 is provided on the upstream side of the first individual intake passage 41 from the connection point of the first branch passage 911.

  A second individual throttle valve 62 is provided on the second individual intake passage 42 upstream of the connection point of the second branch passage 912.

  The first bank 31 is a bank in which at least a part of the exhaust gas discharged from the first bank 31 is taken out by the EGR passage 91 and flows into the first individual intake passage 41 and the second individual intake passage 42 as EGR gas. Yes, and corresponds to “EGR take-out bank” in the present invention.

  On the other hand, the second bank 32 is a bank in which a part of the exhaust discharged from the second bank 32 is not taken out as EGR gas by the EGR passage 91, and corresponds to the “bank without EGR removal” in the present invention.

The EGR valve opening sensor 111 and other various sensors are connected to the ECU 120, and the measurement data is input to the ECU 120. Further, the ECU 120 includes an EGR valve 1
01, the shut-off valve 132, the first individual throttle valve 61, the second individual throttle valve 62, and other various devices are connected, and the operation of these devices is controlled by the ECU 120.

  The ECU 120 is a computer that controls the operation of the engine 1 and has a known configuration such as a ROM that stores various control programs, a CPU that executes the control programs, and a RAM that temporarily stores measurement data. The ECU 120 grasps the operating state such as the load and the rotational speed of the engine 1 based on measurement data input from various sensors, and according to the grasped operating state, the EGR valve 101, the first individual throttle valve 61, and the second individual throttle valve. A control signal is sent to various devices such as the throttle valve 62.

  When the EGR valve 101 is stuck open, as described in the above embodiments, the amount of EGR gas may be excessive and combustion failure may occur. That is, when the EGR valve 101 is fixed open, the first bank 31 corresponds to the “EGR take-out increase bank” in the description of the present invention described above.

  In each of the embodiments described above, by controlling the individual intake VVT mechanism of the EGR take-out increase bank to retard the closing timing of the intake valve or changing the opening of the individual throttle valve to the closed side, The case where the control for reducing the intake amount of the EGR take-out increase bank has been described.

  On the other hand, in this embodiment, when it is detected that the EGR valve 101 is stuck open, fuel cut control is performed in the first bank 31 which is an EGR take-out increase bank.

  As the fuel cut control is performed in the first bank 31, the exhaust gas discharged from the first bank 31 is not burned gas but air, so that the EGR valve 101 is fixed and the EGR gas amount is increased than usual. However, since the EGR gas is not burned gas, it is possible to suppress the occurrence of poor combustion due to excessive inactive components in the intake air.

  However, when air flows into the first individual intake passage 41 or the second individual intake passage 42 as EGR gas in this way, an air-fuel ratio shift occurs in the second bank 32 where fuel cut control is not performed, and combustion is not achieved. It may become stable.

  Further, since the exhaust discharged from the second bank 32 may become leaner than usual, the second pre-stage catalyst 142 and the underfloor catalyst 150 may be exposed to excessively lean exhaust and deteriorate.

  Therefore, in this embodiment, when the open fixing of the EGR valve 101 is detected, the fuel cut control is executed for the first bank 31, and the opening degree of the first individual throttle valve 61 is set closer to the closing side than normal. The opening degree of the second individual throttle valve 62 is controlled to the opening side that is more open than the normal time.

  The opening degree of the first individual throttle valve 61 at this time is set to an opening degree that compensates for the intake amount corresponding to the negative pressure in the cylinder 21 of the first bank 31, and the opening degree of the second individual throttle valve 62 is the second opening degree. The opening is set such that the inflow of EGR gas into the bank 32 can be suppressed.

  The first individual throttle valve 61 is controlled to an opening closer to the closing side than the normal time, and the second individual throttle valve 62 is controlled to an opening side closer to the opening than the normal time. The pressure in the second individual intake passage 42 downstream from the second individual throttle valve 62 becomes higher than the pressure in the first individual intake passage 41 downstream from the 61.

  Accordingly, the air EGR gas in the EGR passage 91 flows more easily into the first branch passage 911 than in the second branch passage 912.

  As a result, the exhaust (air) discharged from the first bank 31 is taken out from the first individual exhaust passage 71 by the EGR passage 91, and most of the exhaust flows into the first branch passage 911 from the EGR passage 91. It passes through the branch passage 911 and flows into the first individual intake passage 41 and flows into the first bank 31.

  That is, the air EGR gas circulates in the circulation path including the first bank 31, the first individual exhaust passage 71, the EGR passage 91, the first branch passage 911, and the first individual intake passage 41 where fuel cut control is performed. Thus, the air EGR gas is suppressed from flowing into the second bank 32.

  Further, in this embodiment, at this time, the shutoff valve 132 is closed to more reliably prevent the inflow of the air EGR gas into the second bank 32.

  Further, since the opening amount of the second individual throttle valve 62 is set to an opening side that is more open than normal, the intake amount of the second bank 32 increases, and accordingly, the fuel injection of the second bank 32 is increased accordingly. The amount was increased.

  By doing so, it is possible to suppress the exhaust from the second bank 32 from being excessively lean, and to suppress the second pre-stage catalyst 142 and the underfloor catalyst 150 from being deteriorated by being exposed to the excessively lean exhaust. It becomes possible.

  Furthermore, since the torque of the second bank 32 increases, it is possible to compensate for the torque shortage caused by the fuel cut control in the first bank 31. Therefore, it is possible to secure a sufficient torque for performing the retreat travel without any trouble.

  A control pattern in which the opening degrees of the first individual throttle valve 61 and the second individual throttle valve 62 are both set to the normal opening degree according to whether or not it is detected that the EGR valve 101 is stuck open, A control pattern in which the opening degree of the individual throttle valve 61 is set to a predetermined opening degree on the side closer to the normal opening degree and the opening degree of the second individual throttle valve 62 is set to the predetermined opening degree on the opening side than the normal opening degree; The control patterns may be switched to one of the two control patterns, but the opening degrees of the first individual throttle valve 61 and the second individual throttle valve 62 are more finely controlled in accordance with the fixed opening degree of the EGR valve 101. You may do it.

  For example, as shown in FIG. 9, the opening degree of the first individual throttle valve 61 is controlled to the closing side opening degree as the fixing opening degree of the EGR valve 101 is the opening side opening degree (large opening degree). The opening degree of the second individual throttle valve 62 may be controlled to the opening degree on the more open side.

  At this time, as shown in FIG. 9, the opening degree of the first individual throttle valve 61 and the second individual throttle valve 62 may be continuously changed according to the fixing opening degree of the EGR valve 101, or stepwise. You may make it change to.

  In this way, even when the fixed opening degree of the EGR valve 101 is large, the air EGR gas can be more preferably circulated in the above-described circulation path including the first bank 31.

Further, the fixed opening of the EGR valve 101 at the time of fixed open and the target opening set by the ECU 120 according to the operating condition of the engine 1 are compared, and the fixed opening is more open than the target opening. Only in such a case, the opening degree of the first individual throttle valve 61 may be changed to the closing side and the opening degree of the second individual throttle valve 62 may be changed to the opening side.

  The control flow of the present embodiment described above will be described with reference to FIG. The routine shown by the flowchart of FIG. 10 is periodically executed by the ECU 120 while the engine 1 is operating.

  In step S301, the ECU 120 determines whether or not the EGR valve 101 is stuck open. In this embodiment, the actual opening degree of the EGR valve 101 measured by the EGR valve opening degree sensor 111 is compared with the target opening degree set by the ECU 120, and the actual opening degree with respect to the change in the target opening degree. When it is detected that the EGR valve 101 has not changed, it is determined that the EGR valve 101 is stuck open.

  If it is determined in step S301 that the EGR valve 101 has been stuck open (Yes), the ECU 120 proceeds to step S302. On the other hand, when it is determined in step S301 that the EGR valve 101 is not open and stuck (No), the ECU 120 proceeds to step S303.

  In step S302, the ECU 120 determines whether or not the fixed opening degree of the EGR valve 101 is on the opening side with respect to the target opening degree.

  If it is determined in step S302 that the fixed opening is on the opening side of the target opening (Yes), the ECU 120 proceeds to step S304. On the other hand, if it is determined in step S302 that the fixed opening is not on the opening side of the target opening (No), the ECU 120 proceeds to step S303.

  In step S303, the ECU 120 performs normal processing on the opening of the first individual throttle valve 61, the opening of the second individual throttle valve 62, the fuel injection amount of the first bank 31, and the fuel injection amount of the second bank 32. Execute.

  That is, the opening degree of the first individual throttle valve 61 and the opening degree of the second individual throttle valve 62 are set to base map values that are predetermined according to the operating state of the engine 1.

  Further, the fuel injection amounts of the first bank 31 and the second bank 32 are set to base map values that are determined in advance according to the operating state of the engine 1. Further, the shutoff valve 132 is opened.

  In step S304, the ECU 120 performs correction processing on the opening degree of the first individual throttle valve 61, the opening degree of the second individual throttle valve 62, the fuel injection amount of the first bank 31, and the fuel injection amount of the second bank 32. Execute.

  That is, the opening degree of the first individual throttle valve 61 is changed to the opening degree on the closing side with respect to the base map value, and the opening degree of the second individual throttle valve 62 is changed to the opening degree on the opening side with respect to the base map value. .

  Further, fuel cut control is performed in the first bank 31, and the fuel injection amount in the second bank 32 is increased from the base map value. The increase in the fuel injection amount of the second bank 32 is determined according to the intake air amount that increases as the opening of the second individual throttle valve 62 is changed to the opening on the opening side with respect to the base map value. It is determined based on the fuel injection amount recalculated so that the fuel ratio becomes stoichiometric. Further, the shutoff valve 132 is closed.

By executing the above routine, when the EGR valve 101 is stuck open and the sticking opening is an opening on the opening side of the target opening, the fuel cut control is performed in the first bank 31. However, a large amount of air EGR gas is prevented from flowing into the second bank 32 and the exhaust from the second bank 32 is excessively lean. Therefore, it is possible to suitably suppress deterioration of the second pre-stage catalyst 142 and the underfloor catalyst 150 downstream of the second bank 32 by being exposed to excessively lean exhaust gas.

  In this embodiment, the shutoff valve 132 corresponds to the shutoff device in the present invention. Further, when the EGR valve 101 is detected as being stuck open, in step S304, the opening of the first individual throttle valve 61 is changed to an opening closer to the base map value, and the opening of the second individual throttle valve 62 is set as the base. The ECU 120 that changes the opening to the opening side of the map value, closes the shut-off valve 132, and increases the fuel injection amount corresponds to the failure time control means in the present invention.

  Next, a fourth embodiment of the present invention will be described. In this embodiment, the fuel cut control is performed in the EGR take-out increase bank as described in the third embodiment, and the air EGR gas derived from the exhaust gas from the EGR take-out increase bank during the fuel cut control is set in the EGR take-out increase bank. An embodiment in which the configuration for controlling the individual throttle valve so as to circulate in the circulation path including it is applied to a system having two EGR extraction banks and two EGR extraction banks as in the second embodiment. It is.

  FIG. 11 is a conceptual diagram schematically showing a schematic configuration of an internal combustion engine to which the EGR device for an internal combustion engine according to the present embodiment is applied and its intake system and exhaust system.

  In FIG. 11, the engine 100 includes a first bank 31 including three cylinders 21, a second bank 32 including three cylinders 22, a third bank 33 including three cylinders 23, and three cylinders 24. And a fourth bank 34.

  A first individual intake passage 41 that communicates with the cylinders 21 of the first bank 31 is connected to the first bank 31.

  The second bank 32 is connected to a second individual intake passage 42 that communicates with the cylinders 22 of the second bank 32.

  A third individual intake passage 43 that communicates with the cylinders 23 of the third bank 33 is connected to the third bank 33.

  A fourth individual intake passage 44 that communicates with the cylinders 24 of the fourth bank 34 is connected to the fourth bank 34.

  The first individual intake passage 41 is provided with a first individual throttle valve 61 that adjusts the amount of intake air flowing through the first individual intake passage 41.

  The second individual intake passage 42 is provided with a second individual throttle valve 62 that adjusts the amount of intake air flowing through the second individual intake passage 42.

  The third individual intake passage 43 is provided with a third individual throttle valve 63 that adjusts the amount of intake air flowing through the third individual intake passage 43.

  The fourth individual intake passage 44 is provided with a fourth individual throttle valve 64 that adjusts the amount of intake air flowing through the fourth individual intake passage 44.

  The first individual intake passage 41, the second individual intake passage 42, the third individual intake passage 43, and the fourth individual intake passage 44 are gathered in a shared intake passage 50 that is shared by all banks upstream.

  A first individual exhaust passage 71 that communicates with the cylinders 21 of the first bank 31 is connected to the first bank 31.

  A second individual exhaust passage 72 that communicates with the cylinders 22 of the second bank 32 is connected to the second bank 32.

  A third individual exhaust passage 73 communicating with the cylinder 23 of the third bank 33 is connected to the third bank 33.

  A fourth individual exhaust passage 74 communicating with the cylinder 24 of the fourth bank 34 is connected to the fourth bank 34.

  The first individual exhaust passage 71, the second individual exhaust passage 72, the third individual exhaust passage 73, and the fourth individual exhaust passage 74 are gathered in a common exhaust passage 80 shared by all banks downstream.

  A first front catalyst 141 is disposed in the first individual exhaust passage 71.

  A second front catalyst 142 is disposed in the second individual exhaust passage 72.

  A third front catalyst 143 is disposed in the third individual exhaust passage 73.

  A fourth front catalyst 144 is arranged in the fourth individual exhaust passage 74.

  An underfloor catalyst 150 is disposed in the shared exhaust passage 80.

  A first EGR passage 91 is connected to the first individual exhaust passage 71 on the downstream side of the first front catalyst 141.

  The first EGR passage 91 branches into a first branch passage 911, a second branch passage 912, a third branch passage 913, and a fourth branch passage 914 at a branch portion 910 on the way.

  The first branch passage 911 is connected to the first individual intake passage 41.

  The second branch passage 912 is connected to the second individual intake passage 42.

  The third branch passage 913 is connected to the third individual intake passage 43.

  The fourth branch passage 914 is connected to the fourth individual intake passage 44.

  A first EGR valve 101 that adjusts the flow rate of the EGR gas that flows through the first EGR passage 91 is provided in the first EGR passage 91 on the upstream side of the branch portion 910. Further, a first EGR valve opening sensor 111 that measures the opening of the first EGR valve 101 is provided.

In the middle of the first branch passage 911, EGR gas in the first branch passage passes through the first individual intake passage 41.
There is provided a shut-off valve 131 capable of shutting off the inflow into the.

  In the middle of the second branch passage 912, a shut-off valve 132 capable of blocking the flow of EGR gas in the second branch passage into the second individual intake passage 42 is provided.

  In the middle of the third branch passage 913, a shutoff valve 133 is provided that can block EGR gas in the third branch passage from flowing into the third individual intake passage 43.

  In the middle of the fourth branch passage 914, a shut-off valve 134 capable of blocking the EGR gas in the fourth branch passage from flowing into the fourth individual intake passage 44 is provided.

  A part of the exhaust discharged from the first bank 31 is taken out by the first EGR passage 91, passes through the first EGR passage 91, passes through the first branch passage 911 to the fourth branch passage 914, and becomes the first individual intake air as EGR gas. It flows into the passage 41 to the fourth individual intake passage 44.

  A second EGR passage 92 is connected to the second individual exhaust passage 72 on the downstream side of the second pre-stage catalyst 142.

  The second EGR passage 92 branches into a first branch passage 921, a second branch passage 922, a third branch passage 923, and a fourth branch passage 924 at a branch portion 920 on the way.

  The first branch passage 921 is connected to the first individual intake passage 41.

  The second branch passage 922 is connected to the second individual intake passage 42.

  The third branch passage 923 is connected to the third individual intake passage 43.

  The fourth branch passage 924 is connected to the fourth individual intake passage 44.

  A second EGR valve 102 that adjusts the flow rate of the EGR gas flowing through the second EGR passage 92 is provided in the second EGR passage 92 on the upstream side of the branch portion 920. Moreover, the 2nd EGR valve opening degree sensor 112 which measures the opening degree of the 2nd EGR valve 102 is provided.

  In the middle of the first branch passage 921, a shut-off valve 231 that can block EGR gas in the first branch passage from flowing into the first individual intake passage 41 is provided.

  In the middle of the second branch passage 922, a shut-off valve 232 that can block the EGR gas in the second branch passage from flowing into the second individual intake passage 42 is provided.

  In the middle of the third branch passage 923, a shut-off valve 233 capable of blocking the flow of EGR gas in the third branch passage into the third individual intake passage 43 is provided.

  In the middle of the fourth branch passage 924, a shut-off valve 234 capable of blocking the EGR gas in the fourth branch passage from flowing into the fourth individual intake passage 44 is provided.

  A part of the exhaust discharged from the second bank 32 is taken out by the second EGR passage 92, passes through the second EGR passage 92, passes through the first branch passage 921 to the fourth branch passage 924, and becomes the first individual intake air as EGR gas. It flows into the passage 41 to the fourth individual intake passage 44.

A first individual throttle valve 61 is provided at a position upstream of the connection point of the first branch passage 911 and upstream of the connection point of the first branch passage 921 in the first individual intake passage 41.

  A second individual throttle valve 62 is provided at a position upstream of the connection point of the second branch passage 912 and upstream of the connection point of the second branch passage 922 in the second individual intake passage 42.

  A third individual throttle valve 63 is provided at a position upstream of the connection point of the third branch passage 913 and upstream of the connection point of the third branch passage 923 in the third individual intake passage 43.

  A fourth individual throttle valve 64 is provided at a position upstream of the connection point of the fourth branch passage 914 and upstream of the connection point of the fourth branch passage 924 in the fourth individual intake passage 44.

  In the first bank 31 and the second bank 32, at least a part of the exhaust discharged from these banks is taken out by the first EGR passage 91 or the second EGR passage 92, and the first individual intake passage 41 to the fourth individual intake air are used as EGR gas. This is a bank that flows into the passage 44 and corresponds to the “bank with EGR removal” in the present invention.

  On the other hand, the third bank 33 and the fourth bank 34 are banks in which a part of the exhaust gas discharged from these banks is not taken out as EGR gas by either the first EGR passage 91 or the second EGR passage 92. Corresponds to the “bank without EGR removal” in FIG.

  The first EGR valve opening sensor 111, the second EGR valve opening sensor 112, and other various sensors are connected to the ECU 120, and the measurement data is input to the ECU 120.

  Further, the ECU 120 includes a first EGR valve 101, a second EGR valve 102, a first individual throttle valve 61, a second individual throttle valve 62, a third individual throttle valve 63, a fourth individual throttle valve 64, a cutoff valve 131, a cutoff valve. 132, a shutoff valve 133, a shutoff valve 134, a shutoff valve 231, a shutoff valve 232, a shutoff valve 233, a shutoff valve 234, and other various devices are connected, and the operation of these devices is controlled by the ECU 120. .

  The ECU 120 is a computer that controls the operation of the engine 1 and has a known configuration such as a ROM that stores various control programs, a CPU that executes the control programs, and a RAM that temporarily stores measurement data and the like. ECU120 grasps | ascertains driving conditions, such as a load of the engine 1, and rotation speed, based on the measurement data input from various sensors, and sends a control signal to the said various apparatus according to the grasped driving | running state.

  Here, the control performed in the system of the present embodiment will be described by taking, as an example, the case where the first EGR valve 101 is stuck open among the two EGR valves.

  When the first EGR valve 101 is stuck open and the sticking opening is larger than the target opening set by the ECU 120 according to the operating conditions of the engine 1, the intake EGR gas amount is excessive. There is a risk of poor combustion.

  That is, when the first EGR valve 101 is fixed open, the first bank 31 corresponds to the “EGR take-out increase bank” in the description of the present invention.

  On the other hand, since it is assumed here that the second EGR valve 102 is not open-fixed, the second bank 32 is the “bank with EGR extraction” in the present invention, but not the “EGR extraction increase bank”.

  In this embodiment, when it is detected that the first EGR valve 101 is stuck open, fuel cut control is performed in the first bank 31 which is an EGR take-out increase bank.

  Further, the opening degree of the first individual throttle valve 61 is controlled to be closer to the closing side than normal, and the opening degree of the second individual throttle valve 62, the third individual throttle valve 63, and the fourth individual throttle valve 64 is set. The opening degree is controlled to be more open than normal.

  Then, the fuel injection amount of the second bank 32 to the fourth bank 34 is increased from the normal time.

  The opening degree of the first individual throttle valve 61 is controlled to be closer to the closing side than normal, and the opening degree of the second individual throttle valve 62, the third individual throttle valve 63, and the fourth individual throttle valve 64 is higher than usual. Also, by controlling the opening on the opening side, the second individual intake passage downstream of the second individual throttle valve 62 with respect to the pressure of the first individual intake passage 41 downstream of the first individual throttle valve 61 is achieved. 42, the pressure in the third individual intake passage 43 downstream from the third individual throttle valve 63 and the pressure in the fourth individual intake passage 44 downstream from the fourth individual throttle valve 64 increase.

  Therefore, the air EGR gas in the first EGR passage 91 is more likely to flow into the first branch passage 911 than in the second branch passage 912 to the fourth branch passage 914. As a result, the exhaust (air) discharged from the first bank 31 where the fuel cut control is performed is taken out from the first individual exhaust passage 71 by the first EGR passage 91 and is transferred from the first EGR passage 91 to the first branch passage 911. Most of the air flows in, passes through the first branch passage 911, flows into the first individual intake passage 41, and flows into the first bank 31.

  That is, the air EGR gas circulates in the circulation path including the first bank 31, the first individual exhaust passage 71, the first EGR passage 91, the first branch passage 911, and the first individual intake passage 41 where the fuel cut control is performed. Thus, the air EGR gas is suppressed from flowing into the second bank 32 to the fourth bank 34.

  Further, in this embodiment, at this time, the shutoff valve 131 is opened and the shutoff valve 132, the shutoff valve 133, and the shutoff valve 134 are closed. All the shut-off valves 231 to 234 are opened.

  Thereby, it is more reliably prevented that the EGR gas in the first EGR passage 91 flows into the second bank 32 to the fourth bank 34.

  And since the opening degree of the 2nd individual throttle valve 62-the 4th individual throttle valve 64 is made into the opening degree of the opening side rather than the normal time, the intake amount of the 2nd bank 32-the 4th bank 34 increases. Accordingly, by increasing the fuel injection amount of the second bank 32 to the fourth bank 34, the exhaust from the second bank 32 to the fourth bank 34 is suppressed from becoming excessively lean, and the second It is possible to prevent the front catalyst 142 to the fourth front catalyst 144 and the underfloor catalyst 150 from being deteriorated by being exposed to excessively lean exhaust gas.

  Furthermore, since the torque of the second bank 32 to the fourth bank 34 increases, it is possible to compensate for the torque shortage caused by the fuel cut control of the first bank 31. Therefore, it is possible to secure a sufficient torque for performing the retreat travel without any trouble.

As in the third embodiment, all the opening degrees of the first individual throttle valve 61 to the fourth individual throttle valve 64 are set to the normal opening degree depending on whether or not it is detected that the first EGR valve 101 is fixed open. And the opening degree of the second individual throttle valve 62 to the fourth individual throttle valve 64 is normally opened while the opening degree of the first individual throttle valve 61 is set to a predetermined opening degree that is close to the normal opening degree. The control pattern may be switched to one of two control patterns, which is a predetermined opening on the opening side with respect to the degree, but depending on the fixing opening of the first EGR valve 101, the first pattern is finer. The opening degree of the individual throttle valve 61 to the fourth individual throttle valve 64 may be controlled.

  Further, the fixed opening degree of the first EGR valve 101 at the time of open fixation and the target opening set by the ECU 120 according to the operating condition of the engine 1 are compared, and the fixed opening degree is larger than the target opening degree. The above-described control may be performed only in the case of the side.

  The control flow of the present embodiment described above will be described with reference to FIG. The routine shown by the flowchart of FIG. 12 is periodically executed by ECU 120 while engine 100 is operating.

  In step S401, the ECU 120 determines whether or not at least one of the first EGR valve 101 and the second EGR valve 102 is openly fixed. In this embodiment, the actual opening degree of the first EGR valve 101 measured by the first EGR valve opening degree sensor 111 is compared with the target opening degree set by the ECU 120, and the actual opening degree is compared with the change in the target opening degree. When it is detected that the opening degree has not changed, it is determined that the first EGR valve 101 is stuck open. Similarly, the second EGR valve 102 is also checked for the presence of open adhesion.

  If it is determined in step S401 that at least one of the first EGR valve 101 or the second EGR valve 102 is stuck open, the ECU 120 proceeds to step S402. On the other hand, when it is determined in step S401 that neither the first EGR valve 101 nor the second EGR valve 102 is open and stuck, the ECU 120 proceeds to step S403.

  In step S402, the ECU 120 determines whether or not the fixed opening degree of the EGR valve determined to be opened and fixed in step S401 is closer to the open side than the target opening degree.

  If it is determined in step S402 that the fixed opening degree of the opened EGR valve is not on the open side with respect to the target opening degree, the ECU 120 proceeds to step S403.

  In step S403, the ECU 120 executes normal processing. That is, the opening degree of the first individual throttle valve 61 to the fourth individual throttle valve 64 is set to a base map value determined in advance according to the operating state of the engine 1. Further, the fuel injection amounts of the first bank 31 to the fourth bank 34 are set to the base map value. In addition, all shut-off valves are opened.

  In step S402, when it is determined that at least the first EGR valve 101 is included in the open-fixed EGR valve and the fixed opening of the first EGR valve 101 is determined to be on the opening side with respect to the target opening, the ECU 120 performs step The process proceeds to S404.

  In step S <b> 404, the ECU 120 performs fuel cut control in the first bank 31. Then, the opening degree of the first individual throttle valve 61 is controlled to be closer to the opening side than the base map value, and the opening degree of the second individual throttle valve 62 to the fourth individual throttle valve 64 is opened from the base map value. Control the opening to the side.

  Further, the shutoff valves 131 and 231 to 234 are opened, and the shutoff valves 132 to 134 are closed. Further, the fuel injection amount of the second bank 32 to the fourth bank 34 is increased from the base map value.

  As a result, the air EGR gas extracted from the exhaust (air) discharged from the first bank 31 that is the EGR extraction increasing bank and in which fuel cut control is performed, flows only into the first bank 31, and the second bank 32- Inflow to the fourth bank 34 is blocked. Therefore, the air EGR gas is circulated in the circulation path including the first bank 31.

  Further, the second bank according to the increase in the intake air amount of the second bank 32 to the fourth bank 34 by the opening degree of the second individual throttle valve 62 to the fourth individual throttle valve 64 being controlled to the opening side opening degree. Since the fuel injection amount of the 32-th to the fourth bank 34 is increased, the exhaust gas discharged from the second bank 32 to the fourth bank 34 is prevented from being excessively lean, and the second bank 32 to the fourth bank. The torque of the bank 34 increases.

  Therefore, it is possible to suppress the exhaust gas flowing into the second pre-stage catalyst 132 to the fourth pre-stage catalyst 134 and the underfloor catalyst 150 from becoming excessively lean, and to compensate for the torque shortage caused by the fuel cut control of the first bank 31. it can.

  In step S402, when it is determined that at least the second EGR valve 102 is included in the open-fixed EGR valve and the fixed opening of the second EGR valve 102 is determined to be on the opening side with respect to the target opening, the ECU 120 performs step. The process proceeds to S405.

  In step S <b> 405, the ECU 120 performs fuel cut control in the second bank 32. Then, the opening degree of the second individual throttle valve 62 is controlled to be closer to the closing side than the base map value, and the first individual throttle valve 61, the third individual throttle valve 63, and the fourth individual throttle valve 64 are opened. The degree is controlled to the opening degree on the opening side with respect to the base map value.

  Further, the shut-off valves 232, 131 to 134 are opened, and the shut-off valves 231, 233, and 234 are closed. Further, the fuel injection amounts of the first bank 31, the third bank 33, and the fourth bank 34 are increased from the base map value.

  As a result, the air EGR gas extracted from the exhaust (air) discharged from the second bank 32 that is an EGR extraction increasing bank and in which fuel cut control is performed flows only into the second bank 32, and the first bank 31, Inflow to the third bank 33 and the fourth bank 34 is blocked. Accordingly, the air EGR gas is circulated in the circulation path including the second bank 32.

  Further, the first bank 31, the third bank 33, and the first bank 31 are controlled by controlling the opening of the first individual throttle valve 61, the third individual throttle valve 63, and the fourth individual throttle valve 64 to the opening side. Since the fuel injection amounts of the first bank 31, the third bank 33, and the fourth bank 34 are increased in accordance with the increase in the intake air amount of the four banks 34, the first bank 31, the third bank 33, and the fourth bank Exhaust exhaust from the exhaust gas 34 is suppressed from becoming excessively lean, and torques of the first bank 31, the third bank 33, and the fourth bank 34 are increased.

  Therefore, it is possible to prevent the exhaust flowing into the first front catalyst 131, the third front catalyst 133, the fourth front catalyst 134, and the underfloor catalyst 150 from being excessively lean, and to be caused by the fuel cut control of the second bank 32. The lack of torque can be compensated.

  In step S402, both the first EGR valve 101 and the second EGR valve 102 are stuck open, and the sticking opening degree of the first EGR valve 101 and the sticking opening degree of the second EGR valve 102 are on the opening side with respect to the target opening degree. If it is determined that there is, the ECU 120 proceeds to step S406.

  In step S <b> 406, the ECU 120 performs fuel cut control in the first bank 31 and the second bank 32. Then, the opening degrees of the first individual throttle valve 61 and the second individual throttle valve 62 are controlled to be closer to the opening side than the base map value, and the opening degrees of the third individual throttle valve 63 and the fourth individual throttle valve 64 are controlled. Is controlled to an opening on the opening side of the base map value.

  Further, the shutoff valves 131, 132, 231, 232 are opened, and the shutoff valves 133, 134, 233, 234 are closed. Further, the fuel injection amounts of the third bank 33 and the fourth bank 34 are increased from the base map value.

  As a result, the air EGR gas extracted from the exhaust (air) exhausted from the first bank 31 and the second bank 32, which is an EGR extraction increasing bank and in which fuel cut control is performed, is the first bank 31 and the second bank 32. Inflow to the third bank 33 and the fourth bank 34 is blocked. Therefore, the air EGR gas circulates in the circulation path including the first bank 31 and / or in the circulation path including the second bank 32.

  Further, the third bank according to the increase in the intake air amount of the third bank 33 and the fourth bank 34 by the opening degree of the third individual throttle valve 63 and the fourth individual throttle valve 64 being controlled to the opening side opening degree. Since the fuel injection amount of the third bank 33 and the fourth bank 34 is increased, it is possible to suppress the exhaust gas exhausted from the third bank 33 and the fourth bank 34 from being excessively lean, and the third bank 33 and the fourth bank 34. The torque of the bank 34 increases.

  Therefore, it is possible to suppress the exhaust gas flowing into the third pre-stage catalyst 133, the fourth pre-stage catalyst 134, and the underfloor catalyst 150 from being excessively lean, and to result from the fuel cut control of the first bank 31 and the second bank 32. Torque shortage can be compensated.

  By executing the above routine, when the first EGR valve 101 and the second EGR valve 102 are stuck open and the sticking opening is an opening closer to the target opening, the first bank 31 and the second bank Even when the fuel cut control is performed at 32, it is suppressed that a large amount of air EGR gas flows into the banks where the fuel cut control is not performed and the exhaust from those banks becomes excessively lean.

  Therefore, it is possible to suitably suppress the deterioration of the upstream catalyst and the underfloor catalyst downstream of the bank where fuel cut control is not performed due to excessive exposure to the lean exhaust gas.

  In this embodiment, the shutoff valves 131 to 134 and 231 to 234 correspond to the shutoff device in the present invention.

  In the present embodiment, when the first EGR valve 101 and / or the second EGR valve 102 is detected as being stuck open, the process of step S404, step S405, or step S406 is performed, so that the first individual throttle valve 61 and / or the second individual throttle are processed. The opening of the valve 62 is changed to the opening on the closing side with respect to the base map value, and the opening of the other individual throttle valve is changed to the opening on the opening side with respect to the base map value, and fuel cut control is performed. The ECU 120 that performs opening / closing control of the shut-off valves 131 to 134 and 231 to 234 so that the air EGR gas derived from the bank with EGR take-out flows into the bank where fuel cut control is not performed, It corresponds to.

In this embodiment, when it is detected that either the first EGR valve 101 or the second EGR valve 102 is stuck open, the fuel cut is performed on the EGR take-out banks of both the first bank 31 and the second bank 32. Control may be performed.

  In this case, since both the first EGR passage 91 and the second EGR passage 92 allow the air EGR gas to flow into the individual intake passages, the opening degrees of the first individual throttle valve 61 and the second individual throttle valve 62 are closed. The opening degree of the third individual throttle valve 63 and the fourth individual throttle valve 64 may be changed to the open side.

  As a result, the EGR gas in the first EGR passage 91 is more likely to flow into the first branch passage 911 and the second branch passage 912 than in the third branch passage 913 and the fourth branch passage 914, and in the second EGR passage 92. The EGR gas is more likely to flow into the first branch passage 921 and the second branch passage 922 than the third branch passage 923 and the fourth branch passage 924.

  Therefore, the exhaust (air) from the first bank 31 and the second bank 32 for which fuel cut control is performed is exhausted from the first bank 31, and passes through the first EGR passage 91 and the first branch passage 911 to the first bank 31. It circulates in the return circulation path, is discharged from the first bank 31, flows into the circulation path including the second bank 32 via the first EGR passage 91 and the second branch passage 912, is discharged from the second bank 32, and is discharged to the second EGR passage. Circulation through a circulation path returning to the second bank 32 through the second bank 32 and the second branch passage 922, or circulation including the first bank 31 through the second EGR passage 92 and the first branch passage 921 discharged from the second bank 32. Flows into the path.

  Thereby, it is suppressed that air EGR gas flows in into the 3rd bank 33 and the 4th bank 34 which are the banks without EGR extraction. Then, according to the increase in the intake air amount of the third bank 33 and the fourth bank 34 due to the opening degree of the third individual throttle valve 63 and the fourth individual throttle valve 64 being changed to the open side, the third bank 33 and Since the fuel injection amount of the fourth bank 34 is increased, it is possible to prevent the third pre-stage catalyst 143, the fourth pre-stage catalyst 144, and the underfloor catalyst 150 from being deteriorated by being exposed to excessively lean exhaust gas. It is possible to avoid a torque shortage caused by the fuel cut control being performed in the bank 31 and the second bank 32.

  In this way, when the fuel cut control is uniformly performed on the bank with EGR removal, it is sufficient that the cutoff valve is provided only for blocking the inflow of EGR gas from each EGR passage to the bank without EGR removal.

  That is, the shutoff valve (shutoff valve) that shuts off the flow of EGR gas into the individual intake passages (third individual intake passage 43, fourth individual intake passage 44) of the banks without taking out EGR (third bank 33, fourth bank 34). 133, 134, 233, 234), and fuel cut control is performed in the first bank 31 and the second bank 32 at the time of detecting the open sticking of any of the EGR valves (first EGR valve 101, second EGR valve 102). Accordingly, the shut-off valves 133, 134, 233, and 234 may be shut off.

  The above-described embodiment is an example for explaining the present invention, and various modifications can be made to the above-described embodiment without departing from the gist of the present invention.

  For example, in the above embodiment, an engine system having two or four banks having three cylinders per bank has been described as an example. However, the number of cylinders per bank and the number of banks included in the engine system are described above. It is not restricted to the number illustrated in the example.

Moreover, the structure of the front | former stage catalyst and underfloor catalyst in Example 3 and 4 does not need to be restricted to this. If the engine system has a configuration including at least one exhaust purification catalyst at a location where the exhaust gas flowing out from the bank without EGR removal flows, it is possible to suppress deterioration of the exhaust purification catalyst by applying the present invention. The effects of the present invention can be enjoyed.

  In the first and second embodiments, the case where the EGR passage is connected to the common intake passage has been described as an example. However, in the first and second embodiments, the EGR passage branches off in the middle as in the third and fourth embodiments. It can also be configured to connect to individual intake passages of each bank.

1 is a diagram illustrating a schematic configuration of an internal combustion engine to which an EGR device according to Embodiment 1 is applied, and an intake system and an exhaust system thereof. In Example 1, the figure which represents the valve closing timing of the intake valve of the 1st bank and the 2nd bank in each of the normal time when the EGR valve is not open stuck and when the EGR valve is stuck open is detected. It is. In Example 1, it is a figure showing an example of the relationship between the adhesion opening degree of an EGR valve, and the valve closing timing of the intake valve of a 1st bank and a 2nd bank. 4 is a flowchart illustrating a closing timing control routine for an intake valve that is performed in accordance with whether or not an EGR valve is stuck in the first embodiment. It is a figure which shows schematic structure of the internal combustion engine to which the EGR apparatus which concerns on Example 2 is applied, its intake system, and an exhaust system. In Example 2, it is a figure showing an example of the relationship between the adhesion opening degree of an EGR valve, and the opening degree of the individual throttle valve of each bank. In Example 2, it is a flowchart showing the opening degree control routine of an individual throttle valve performed according to the presence or absence of adhesion of an EGR valve. FIG. 7 is a diagram illustrating a schematic configuration of an internal combustion engine to which an EGR device according to a third embodiment is applied, and an intake system and an exhaust system thereof. In Example 3, it is a figure showing an example of the relationship between the adhesion opening degree of an EGR valve, and the opening degree of the individual throttle valve of each bank. In Example 3, it is a flowchart showing the opening degree control routine of the separate throttle valve and cutoff valve performed according to the presence or absence of adhesion of an EGR valve. FIG. 10 is a diagram illustrating a schematic configuration of an internal combustion engine to which an EGR device according to a fourth embodiment is applied, and an intake system and an exhaust system thereof. In Example 4, it is a flowchart showing the opening degree control routine of the separate throttle valve and cutoff valve performed according to the presence or absence of adhesion of the EGR valve.

Explanation of symbols

1 Engine 2 First bank 3 Second bank 4 Cylinder 5 Cylinder 6 First individual intake passage 7 Second individual intake passage 8 Shared intake passage 9 Second individual exhaust passage 10 First individual exhaust passage 11 Common exhaust passage 12 EGR passage 13 EGR valve 14 Throttle valve 15 Second intake VVT mechanism 16 First intake VVT mechanism 17 EGR valve opening sensor 18 ECU
21 cylinder 22 cylinder 23 cylinder 24 cylinder 31 first bank 32 second bank 33 third bank 34 fourth bank 41 first individual intake passage 42 second individual intake passage 430 first common intake passage 50 common intake passage 500 second common Intake passage 61 First individual throttle valve 62 Second individual throttle valve 63 Third individual throttle valve 64 Fourth individual throttle valve 630 Shared throttle valve 71 First individual exhaust passage 72 Second individual exhaust passage 73 Third individual exhaust passage 74 4 Individual exhaust passage 80 Shared exhaust passage 91 First EGR passage 92 Second EGR passage 910 Branch portion 911 First branch passage 912 Second branch passage 913 Third branch passage 914 Fourth branch passage 920 Branch portion 921 First branch passage 922 Second Branch passage 923 Third branch passage 924 Fourth branch passage 101 First EGR valve 111 First EGR valve Opening sensor 102 Second EGR valve 112 Second EGR valve opening sensor 120 ECU
131 shut-off valve 132 shut-off valve 133 shut-off valve 134 shut-off valve 231 shut-off valve 232 shut-off valve 233 shut-off valve 141 shut-off valve 141 first pre-stage catalyst 142 second pre-stage catalyst 143 third pre-stage catalyst 144 fourth pre-stage catalyst 150 under-floor catalyst

Claims (12)

An internal combustion engine having a plurality of banks;
One or a plurality of EGR passages that take out at least a part of the exhaust from a bank with a predetermined EGR take-out that is a part of the plurality of banks and flow into the intake passage of the internal combustion engine as EGR gas;
An EGR valve provided in each EGR passage;
An intake air amount control means for controlling an intake air amount flowing into the bank with each EGR take-out,
A failure detection means for detecting open adhesion of each EGR valve;
When the failure detection means detects that the EGR valve is stuck open, a part of the exhaust gas is taken out as EGR gas by the EGR passage provided with the opened EGR valve in the EGR take-out bank. An EGR device for an internal combustion engine, comprising: a failure-time control means for reducing an intake air amount of an EGR take-out bank configured as described above from a normal time when the EGR valve is not open and fixed. In claim 1,
As the opening degree of the open and fixed EGR valve is the opening side, the failure time control means extracts a part of the exhaust as EGR gas through the EGR passage provided with the open and fixed EGR valve. An EGR device for an internal combustion engine, wherein the intake air amount of the bank with EGR extraction is further reduced. In claim 1 or 2,
Further comprising individual intake passages individually connected to the EGR take-out banks,
The intake air amount control means has an individual throttle valve provided in each individual intake passage,
When the failure detection means detects that the EGR valve is stuck open, the failure time control means takes out part of the exhaust gas as EGR gas through the EGR passage provided with the open and stuck EGR valve. EGR of an internal combustion engine characterized in that the opening of the individual throttle valve provided in the individual intake passage connected to the take-out bank is set to an opening closer to the closing side than the normal time when the EGR valve is not fixed. apparatus. In claim 1 or 2,
The intake air amount control means has an intake VVT mechanism capable of variably controlling the intake valve timing of the cylinders in the bank with each EGR take-out,
When the failure detecting means detects that the EGR valve is stuck open, the failure control means is configured to take out part of the exhaust gas as EGR gas through the EGR passage provided with the open and stuck EGR valve. An EGR device for an internal combustion engine, wherein the closing timing of an intake valve of a cylinder in a take-out bank is delayed from a normal time when the EGR valve is not fixed. In any one of Claims 1-4,
When the failure detecting means detects that the EGR valve is stuck open, the failure control means is configured to take out part of the exhaust gas as EGR gas through the EGR passage provided with the open and stuck EGR valve. An EGR device for an internal combustion engine, characterized in that fuel cut control is performed on a cylinder in a take-out bank. In claim 3,
The end of the EGR passage on the side of the intake passage is connected to at least the individual intake passage of each EGR take-out bank,
Each individual throttle valve is provided at a position upstream of a connection point of the EGR passage in each individual intake passage,
An exhaust purification device provided in an exhaust system of the internal combustion engine;
When the failure detection means detects that the EGR valve is open and stuck, the failure control means is configured to control the exhaust gas through an EGR passage provided with the open and stuck EGR valve in the EGR take-out bank. The fuel cut control is performed on the cylinders of the EGR take-out bank configured to take out the EGR gas as EGR gas, and the individual throttle valve provided in the individual intake passage connected to the EGR take-out bank An EGR device for an internal combustion engine, characterized in that the opening is set to an opening closer to the closing side than normal when the EGR valve is not open and fixed. In claim 6,
As the opening degree of the open and fixed EGR valve is the opening side, the failure time control means extracts a part of the exhaust as EGR gas through the EGR passage provided with the open and fixed EGR valve. An EGR device for an internal combustion engine, characterized in that an opening of an individual throttle valve provided in an individual intake passage connected to an EGR take-out bank is set to a close side opening. In claim 6 or 7,
A shutoff device capable of shutting off EGR gas flowing through the EGR passage from flowing into a bank without EGR removal, which is a bank in which a part of the exhaust gas is not taken out as EGR gas by any of the EGR passages; ,
When the failure detecting means detects that the EGR valve is stuck open, the failure time control means causes an EGR gas to flow into the bank without EGR removal from the EGR passage provided with the opened EGR valve. Is shut off by the shut-off device. In any one of Claims 1-8,
A second intake air amount control means for controlling an intake air amount flowing into a bank without EGR removal, which is a bank where a part of the exhaust gas is not taken out as EGR gas by any of the EGR passages;
A second failure time control means for increasing an intake air amount of the bank without EGR removal when compared to a normal time when the EGR valve is not openly fixed when the failure detection means detects that the EGR valve is stuck open;
An EGR device for an internal combustion engine, further comprising: In claim 9,
The EGR valve of the internal combustion engine, wherein the second failure time control means increases the intake air amount of the bank without EGR removal as the opening degree of the opened EGR valve is the opening side opening degree. apparatus. In claim 9 or 10,
An individual intake passage individually connected to each EGR no-takeout bank or a common intake passage shared by each EGR no-takeout bank,
The second intake amount control means has an individual throttle valve provided in each individual intake passage or a shared throttle valve provided in the shared intake passage,
When the EGR valve is stuck open by the failure detection means, the second failure time control means determines the opening degree of the individual throttle valve or the common throttle valve at a normal time when the EGR valve is not stuck. An EGR device for an internal combustion engine, characterized in that the opening degree is more open than that. In claim 9 or 10,
The second intake air amount control means has a second intake VVT mechanism capable of variably controlling the intake valve timing of the cylinders of each of the EGR removal-free banks,
The second failure time control means is configured such that when the failure detection means detects that the EGR valve is stuck open, the EGR valve is stuck open at the closing timing of the intake valve of the cylinder of the bank without EGR removal. An EGR device for an internal combustion engine characterized by being advanced more than normal.

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