JP2014234805A - Exhaust gas recirculation device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device of an internal combustion engine capable of suppressing abnormal combustion generated by condensate water by control for suppressing a recirculation amount of exhaust gas.SOLUTION: An exhaust gas recirculation device 16 for circulating exhaust gas of an internal combustion engine 1 from an exhaust side to a suction side includes: a condensate water detection unit 29 for detecting condensate water generating in a recirculation passage 18 or in a suction passage 2; and a suppression control unit 31 for suppressing a recirculation amount of the exhaust gas when the condensate water is detected. It also includes: a condensate water disappearance detection unit 30 for detecting disappearance of the condensate water after the condensate water is detected; and a release control unit 32 for releasing the suppression control when the disappearance of the condensate water is detected.

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine, and more particularly to an exhaust gas recirculation device for an internal combustion engine that recirculates a part of exhaust gas to an intake system.

As an exhaust device for an internal combustion engine, an exhaust gas recirculation device that lowers a combustion temperature by recirculating a part of exhaust gas to an intake passage and sending it into a cylinder is known. This exhaust gas recirculation device is used, for example, to recirculate exhaust gas and suppress abnormal combustion when the combustion temperature becomes excessively high and abnormal combustion occurs. The exhaust gas recirculation device can suppress harmful substances such as NOx generated by abnormal combustion by recirculating exhaust gas in this way.
2. Description of the Related Art Conventionally, an exhaust gas recirculation device for an internal combustion engine has been known that includes a heat exchanger (EGR cooler) in the middle of a recirculation passage in order to efficiently reduce the combustion temperature in a cylinder. However, in the exhaust gas recirculation apparatus equipped with such a heat exchanger, condensed water is generated in the recirculation passage or the intake passage due to cooling of the exhaust gas, and this condensed water may adversely affect the combustion of the internal combustion engine, parts, and the like. is there.

Therefore, in Patent Document 1 below, in order to solve this problem, an operation information detection unit that detects information on direct and indirect factors related to the generation of condensed water in the low-pressure EGR cooler and the intercooler, and this operation information detection The indirect factor related to the generation of condensate detected in the unit is applied to the set map to determine the low pressure EGR control duty, and the duty of the low pressure EGR valve is controlled according to the condition of the direct factor related to the generation of condensate Then, a control unit that suppresses the generation of condensed water in the intercooler and the low-pressure EGR cooler, and a low-pressure EGR amount (that is, an exhaust gas recirculation amount) is adjusted according to a duty control signal applied from the control unit. A low-pressure EGR system control device including a low-pressure EGR valve is disclosed.
In addition, if the rear end temperature of the intercooler is lower than the set first reference temperature and the boost pressure is lower than the first reference pressure, the control unit determines that the condensate generation condition of the intercooler is The EGR valve is closed to control the low pressure EGR amount to “0%”.

According to this low pressure EGR system controller, the generation of condensed water is minimized by controlling the amount of EGR by optimizing mapping of various control variables that directly affect the factors, thereby intercoolers, turbochargers, low pressure EGR coolers, The durability, reliability, and stability of engine parts including a low pressure EGR valve, a combustion chamber, and the like can be improved.
Further, according to the low pressure EGR system control device, it is possible to realize improvement in fuel consumption and reduction in NOx by optimally controlling the low pressure EGR valve. Furthermore, when condensed water is generated, the temperature of the intercooler can be increased and the generation of condensed water can be suppressed by closing the low-pressure EGR valve and setting the amount of low-pressure EGR to 0%.

JP 2012-87779 A

  However, in an exhaust gas recirculation device for an internal combustion engine such as that disclosed in Patent Document 1, control is performed to suppress the exhaust gas recirculation amount (EGR amount) to suppress the generation of condensed water. If this is done, there is a risk that abnormal combustion of the internal combustion engine is likely to occur because sufficient exhaust gas is not sent into the cylinder.

  Therefore, the present invention has been made in view of the above problems, and provides an exhaust gas recirculation device for an internal combustion engine that can suppress abnormal combustion caused by control for suppressing the recirculation amount of exhaust gas. Objective.

  The present invention is an exhaust gas recirculation device that circulates exhaust gas of an internal combustion engine from an exhaust side to an intake side, and detects a condensed water detection unit that detects condensed water generated in a recirculation passage or an intake passage, and the condensed water is detected. In the exhaust gas recirculation apparatus including a suppression control unit that suppresses the recirculation amount of the exhaust gas, the condensed water disappearance detection unit that detects disappearance of the condensed water after the condensed water is detected, and the condensation And a cancellation control unit that cancels the suppression control when water loss is detected.

In this invention, when the disappearance of the condensed water is detected, the control for suppressing the recirculation amount of the exhaust gas can be canceled, so that the recirculation amount of the exhaust gas can be quickly restored after the disappearance of the condensed water. .
Therefore, after the disappearance of the condensed water, the abnormal combustion of the internal combustion engine can be quickly suppressed.

FIG. 1 is a control flowchart of an exhaust gas recirculation device for an internal combustion engine. Example 1 FIG. 2 is a system configuration diagram of an exhaust gas recirculation device for an internal combustion engine. Example 1 FIG. 3 is a control flowchart of the exhaust gas recirculation device for the internal combustion engine. (Example 2) FIG. 4 is a system configuration diagram of an exhaust gas recirculation device for an internal combustion engine. (Example 2) FIG. 5 is a control flowchart of the exhaust gas recirculation device for the internal combustion engine. (Example 3) FIG. 6 is a system configuration diagram of an exhaust gas recirculation device for an internal combustion engine. (Example 3)

  Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show Embodiment 1 of the present invention. In FIG. 2, the internal combustion engine 1 includes an intake passage 8 in which an air cleaner 2, an intake pipe 3, a throttle body 4, a surge tank 5, and an intake manifold 6 are sequentially connected, and intake air supplied to each cylinder 7 flows. . The throttle body 4 includes a throttle valve 9. The internal combustion engine 1 further includes an exhaust passage 15 in which an exhaust manifold 10, a catalyst 11, an exhaust pipe 12, a muffler 13, and a rear exhaust pipe 14 are sequentially connected, and exhaust gas discharged from each cylinder 7 flows. .
The internal combustion engine 1 includes an exhaust gas recirculation device 16 that circulates part of the exhaust gas from the exhaust passage 15 side to the intake passage 8 side. The exhaust gas recirculation device 16 includes a recirculation pipe 17 that connects the surge tank 5 and the exhaust pipe 12, and includes a recirculation path 18 that connects the exhaust passage 15 of the exhaust pipe 12 to the intake passage 8 of the surge tank 5. The reflux pipe 17 includes an EGR cooler 19 and an EGR valve 20. The EGR cooler 19 cools the EGR gas introduced from the exhaust passage 15 into the recirculation passage 18 by heat exchange with outside air or cooling water of the internal combustion engine 1 or the like. The EGR valve 20 adjusts the recirculation amount (EGR amount) of the exhaust gas circulated from the exhaust passage 15 to the intake passage 8 by changing the exhaust gas passage cross section of the recirculation passage 18.
The EGR valve 20 is controlled by the control device 21 to change the exhaust gas passage cross section of the recirculation passage 18 and adjusts the recirculation amount of the exhaust gas. As means for inputting information for adjusting the exhaust gas recirculation amount, the control device 21 includes an intake air amount sensor 22 for detecting the intake air amount, an intake air temperature sensor 23 for detecting the intake air temperature (outside air temperature), a crank A crank angle sensor 24 for detecting the rotation angle (crank angle) of the shaft, a cam angle sensor 25 for detecting the rotation angle (cam angle) of the cam shaft, a water temperature sensor 26 for detecting the cooling water temperature, and the upstream side of the catalyst 11. An upstream exhaust sensor 27 that detects an exhaust gas component and a downstream exhaust sensor 28 that detects an exhaust gas component downstream of the catalyst 11 are connected. The control device 21 controls the EGR valve 20 based on information input from these sensors 22 to 28.

The control device 21 includes a condensed water detection unit 29 and a suppression control unit 30. The condensed water detection unit 29 detects condensed water generated in the reflux passage 18 or the intake passage 8. The condensed water affects the combustion of the internal combustion engine 1 and fluctuates the rotational speed (hereinafter referred to as “engine rotational speed”). Therefore, the condensed water detection unit 29 monitors the engine speed calculated from the crank angle detected by the crank angle sensor 24. If the fluctuation value of the engine speed is equal to or greater than the rotational speed setting value for suppression, the condensed water is monitored. Detect that there is. The rotational speed setting value for suppression is set by measuring in advance the fluctuation value of the engine speed due to the generation of condensed water.
The suppression control unit 30 suppresses the recirculation amount of the exhaust gas when the condensed water detection unit 29 detects that condensed water is generated in the recirculation passage 18 or the intake passage 8. The suppression control unit 30 controls the EGR valve 20 to control the EGR valve 20 so that the exhaust gas passage section of the recirculation passage 18 becomes smaller than that during normal control, thereby suppressing the recirculation amount of the exhaust gas.
The exhaust gas recirculation device 16 includes a condensate disappearance detection unit 31 and a release control unit 32 in the control device 21. The condensed water disappearance detection unit 31 detects the disappearance of the condensed water after the condensed water is detected by the condensed water detection unit 29. The condensed water disappearance detection unit 31 detects the disappearance of the condensed water based on the engine speed of the internal combustion engine 1 after the condensed water is detected. Specifically, when the engine speed calculated from the crank angle detected by the crank angle sensor 24 is equal to or higher than the release speed setting value, the condensed water disappearance detection unit 31 eliminates the influence of the condensed water on the combustion. And the disappearance of the condensed water is detected. The release rotational speed setting value is set by measuring in advance the increase in engine rotational speed due to the disappearance of condensed water.
When the disappearance of the condensed water is detected by the condensed water disappearance detection unit 31, the cancel control unit 32 cancels the suppression control of the exhaust gas recirculation amount by the suppression control unit 30. The release control unit 32 releases the suppression control of the exhaust gas recirculation amount by causing the control device 21 to control the EGR valve 20 so that the exhaust gas passage cross section of the recirculation passage 18 returns to the normal control size.

Next, the operation will be described.
The exhaust gas recirculation device 16 of the internal combustion engine 1 controls the EGR valve 20 so as to change the exhaust gas passage cross section of the recirculation passage 18 according to the operating state of the internal combustion engine 1 by the control device 21. The amount of recirculation of exhaust gas (EGR gas) introduced into the intake passage 8 through the recirculation passage 18 is adjusted to reduce nitrogen oxides in the exhaust gas and improve fuel efficiency at partial load.
When the exhaust gas recirculation device 16 of the internal combustion engine 1 suppresses the recirculation amount of the exhaust gas in order to eliminate the condensed water generated in the recirculation passage 18 or the intake passage 8, the disappearance of the condensed water is determined based on the engine speed. Detect and promptly return the exhaust gas recirculation amount.
As shown in FIG. 1, the exhaust gas recirculation device 16 is a low temperature at which the intake air temperature (outside air temperature) detected by the intake air temperature sensor 23 is less than the suppression temperature set value while the control device 21 normally controls the exhaust gas recirculation amount. When the control program for suppressing the recirculation amount is started under the environment (100), the condensed water detection unit 29 determines whether or not the fluctuation value of the engine speed is equal to or greater than the suppression rotation fluctuation setting value (101). ).
If this determination (101) is NO, the process proceeds to determination (104) as to whether the engine speed is equal to or higher than the release speed setting value. When the determination (101) is YES, the condensed water detection unit 29 determines that condensed water has been generated, substitutes “1” for the condensed water determination flag Wf (102), and the suppression control unit 30 sets the EGR permission flag Ef. “0” is substituted (103).
When the suppression control unit 30 substitutes “0” for the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage section of the recirculation passage 18 becomes small, and the recirculation amount of the exhaust gas is normally set. Suppress than when controlling.
After suppressing the recirculation amount of the exhaust gas, the condensed water disappearance detection unit 31 determines whether or not the engine speed is equal to or higher than the release speed setting value (104).
If this determination (104) is NO, this determination (104) is repeated. When this determination (104) is YES, the condensed water disappearance detection unit 31 determines that the condensed water has disappeared, substitutes “0” for the condensed water determination flag Wf (105), and the release control unit 32 determines the EGR permission flag. “1” is substituted into Ef (106), and the program is ended (107).
When the release control unit 32 assigns “1” to the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage section of the reduced recirculation passage 18 returns to the original size, and the exhaust gas is discharged. The suppression control of the gas recirculation amount is canceled and normal control is resumed.

In this way, the exhaust gas recirculation device 16 of the internal combustion engine 1 suppresses the generation of condensed water by suppressing the recirculation amount of the exhaust gas when condensed water is generated, and then when the disappearance of the condensed water is detected, the exhaust gas Since the control for suppressing the recirculation amount of the exhaust gas can be released, the recirculation amount of the exhaust gas can be quickly restored after the disappearance of the condensed water. Therefore, after disappearance of the condensed water, exhaust gas can be sufficiently sent to the cylinder 7 and abnormal combustion of the internal combustion engine 1 can be quickly suppressed.
Further, since the exhaust gas recirculation device 16 of the internal combustion engine 1 detects the disappearance of the condensed water based on the engine speed of the internal combustion engine 1 after the condensed water is detected, the condensed water has no influence on the internal combustion engine 1. Therefore, the recirculation amount of the exhaust gas can be restored at an appropriate time.

3 and 4 show Embodiment 2 of the present invention. As shown in FIG. 4, the internal combustion engine 1 according to the second embodiment has the same configuration as that of the first embodiment. Refer to it. The exhaust gas recirculation device 16 of the internal combustion engine 1 includes a recirculation pipe 17, a recirculation passage 18, an EGR cooler 19, and an EGR valve 20. The EGR valve 20 is controlled by the control device 21 and adjusts the exhaust gas recirculation amount (EGR amount).
The control device 21 includes an intake air amount sensor 22, an intake air temperature sensor 23, a crank angle sensor 24, a cam angle sensor 25, a water temperature sensor 26, an upstream exhaust sensor 27, and a downstream exhaust sensor 28. Connected. The control device 21 controls the EGR valve 20 based on information input from these sensors 22 to 28.
The control device 21 includes a condensed water detection unit 29, a suppression control unit 30, a condensed water disappearance detection unit 31, and a release control unit 32, and further includes a timer unit 33. When the condensed water detecting unit 29 detects the generation of condensed water, the time measuring unit 33 starts measuring time and measures the elapsed time since the condensed water was detected.
The condensed water detection unit 29 is generated in the recirculation passage 18 or the intake passage 8 when the fluctuation value of the engine speed calculated from the crank angle detected by the crank angle sensor 24 is equal to or larger than the rotational speed setting value for suppression. Condensate is detected. When the condensate detection unit 29 detects that condensed water is generated in the recirculation passage 18 or the intake passage 8, the suppression control unit 30 makes the exhaust gas passage section of the recirculation passage 18 smaller than that during normal control. The control device 21 controls the EGR valve 20 to suppress the exhaust gas recirculation amount.
The condensed water disappearance detection unit 31 detects the disappearance of the condensed water based on the elapsed time from when the condensed water was detected by the condensed water detection unit 29. Specifically, when the elapsed time measured by the time measuring unit 33 is equal to or greater than the release time set value, the condensed water disappearance detecting unit 31 detects the disappearance of the condensed water. The release time setting value is set by measuring in advance the time required for the disappearance of the condensed water. When the disappearance of condensed water is detected by the condensed water disappearance detection unit 31, the release control unit 32 cancels the suppression control of the exhaust gas recirculation amount by the suppression control unit 30. The release control unit 32 releases the suppression control of the exhaust gas recirculation amount by causing the control device 21 to control the EGR valve 20 so that the exhaust gas passage cross section of the recirculation passage 18 returns to the normal control size.

Next, the operation will be described.
The exhaust gas recirculation device 16 of the internal combustion engine 1 detects the disappearance of the condensed water based on the elapsed time when the recirculation amount of the exhaust gas is suppressed to eliminate the condensed water generated in the recirculation passage 18 or the intake passage 8. Quickly return the exhaust gas recirculation amount.
As shown in FIG. 3, the exhaust gas recirculation device 16 is a low temperature environment in which the intake air temperature (outside air temperature) detected by the intake air temperature sensor 23 is less than the suppression temperature set value while the control device 21 controls the recirculation amount of the exhaust gas. When the control program for suppressing the recirculation amount is started (200), the condensed water detector 29 determines whether the fluctuation value of the engine speed is equal to or greater than the rotational speed setting value for suppression (201). .
When this determination (201) is NO, the process proceeds to determination (205) as to whether the elapsed time measured by the time measuring unit 33 is equal to or greater than the release time set value. When the determination (201) is YES, the condensed water detection unit 29 determines that condensed water has been generated, substitutes “1” for the condensed water determination flag Wf (202), and the suppression control unit 30 sets the EGR permission flag Ef. “0” is substituted (203), and the timing by the timing unit 33 is started (204).
When the suppression control unit 30 substitutes “0” for the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage section of the recirculation passage 18 becomes small, and the recirculation amount of the exhaust gas is normally set. Suppress than when controlling.
When the suppression of the exhaust gas recirculation amount is started by detecting the generation of condensed water and the timing by the timing unit 33 is started (204), the elapsed time measured by the timing unit 33 by the condensed water disappearance detection unit 31 is set as a release time setting value. It is judged whether it is above (205).
If this determination (205) is NO, this determination (205) is repeated. When this determination (205) is YES, the condensed water disappearance detection unit 31 determines that the condensed water has disappeared, substitutes “0” for the condensed water determination flag Wf (206), and the release control unit 32 performs the EGR permission flag. “1” is substituted into Ef (207), and the program is ended (208).
When the release control unit 32 assigns “1” to the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage section of the reduced recirculation passage 18 returns to the original size, and the exhaust gas is discharged. The suppression control of the gas recirculation amount is canceled and normal control is resumed.

In this way, the exhaust gas recirculation device 16 of the internal combustion engine 1 suppresses the generation of condensed water by suppressing the recirculation amount of the exhaust gas when condensed water is generated, and then when the disappearance of the condensed water is detected, the exhaust gas Since the control for suppressing the recirculation amount of the exhaust gas can be released, the recirculation amount of the exhaust gas can be quickly restored after the disappearance of the condensed water. Therefore, after disappearance of the condensed water, exhaust gas can be sufficiently sent to the cylinder 7 and abnormal combustion of the internal combustion engine 1 can be quickly suppressed.
Further, since the exhaust gas recirculation device 16 of the internal combustion engine 1 detects the disappearance of the condensed water based on the elapsed time from when the condensed water was detected, the condensed water was vaporized or consumed during the suppression of the recirculation amount. Since the suppression control can be canceled after confirming the above, the reflux amount can be restored at an appropriate time.

5 and 6 show Embodiment 3 of the present invention. As shown in FIG. 6, the internal combustion engine 1 according to the third embodiment has the same configuration as that of the first embodiment. Refer to it. Furthermore, in addition to the configuration of the first embodiment, the internal combustion engine 1 of the third embodiment includes an ignition coil 34 with an ion current detection function in each cylinder 7. The ignition coil 34 with an ion current detection function supplies a current for generating a spark to the spark plug in the cylinder 7 and detects an ion current value generated by combustion in the cylinder 7. The ion current value generated by the combustion is useful as information indicating the combustion state, and decreases due to the deterioration of the combustion state.
The exhaust gas recirculation device 16 of the internal combustion engine 1 includes a recirculation pipe 17, a recirculation passage 18, an EGR cooler 19, and an EGR valve 20. The EGR valve 20 is controlled by the control device 21 and adjusts the exhaust gas recirculation amount (EGR amount).
The control device 21 includes an intake air amount sensor 22, an intake air temperature sensor 23, a crank angle sensor 24, a cam angle sensor 25, a water temperature sensor 26, an upstream exhaust sensor 27, a downstream exhaust sensor 28, The ignition coil 34 with the ion current detection function is connected. The control device 21 controls the EGR valve 20 based on information input from these sensors 22 to 28.
The control device 21 includes a condensed water detection unit 29 and a suppression control unit 30. The condensed water detection unit 29 detects condensed water generated in the recirculation passage 18 or the intake passage 8 when the ion current value detected by the ignition coil 34 with an ion current detection function is less than the current setting value for suppression. The current setting value for suppression is set by measuring in advance a decrease in ion current value due to the generation of condensed water.
The suppression control unit 30 suppresses the recirculation amount of the exhaust gas when the condensed water detection unit 29 detects that condensed water is generated in the recirculation passage 18 or the intake passage 8. When the condensate detection unit 29 detects the generation of condensate, the suppression control unit 30 causes the control device 21 to control the EGR valve 20 so that the exhaust gas passage section of the recirculation passage 18 becomes smaller than that during normal control. The exhaust gas recirculation amount is suppressed.
The exhaust gas recirculation device 16 includes a condensate disappearance detection unit 31 and a release control unit 32 in the control device 21. The condensed water disappearance detection unit 31 detects the disappearance of the condensed water after the condensed water is detected by the condensed water detection unit 29. The condensed water disappearance detection unit 31 detects the disappearance of the condensed water based on the ion current value detected by the ignition coil 34 with the ion current detection function after the condensed water is detected. Specifically, when the ionic current value detected by the ignition coil 34 with the ionic current detection function is equal to or greater than the release current set value, the condensed water disappearance detection unit 31 detects the disappearance of the condensed water. The release current set value is set by measuring in advance the increase in ion current value due to the disappearance of condensed water.
When the disappearance of the condensed water is detected by the condensed water disappearance detection unit 31, the cancel control unit 32 cancels the suppression control of the exhaust gas recirculation amount by the suppression control unit 30. The release control unit 32 releases the suppression control of the exhaust gas recirculation amount by causing the control device 21 to control the EGR valve 20 so that the exhaust gas passage cross section of the recirculation passage 18 returns to the normal control size.

Next, the operation will be described.
The exhaust gas recirculation device 16 of the internal combustion engine 1 detects the disappearance of the condensed water based on the ionic current value when the recirculation amount of the exhaust gas is suppressed in order to eliminate the condensed water generated in the recirculation passage 18 or the intake passage 8. As a result, the exhaust gas recirculation amount is promptly restored.
As shown in FIG. 5, the exhaust gas recirculation device 16 is in a low temperature environment in which the intake air temperature (outside air temperature) detected by the intake air temperature sensor 23 is less than the suppression temperature set value while the control device 21 controls the recirculation amount of the exhaust gas. When the control program for suppressing the reflux amount is started (300), the condensed water detection unit 29 determines whether the ion current value is less than the suppression current set value (301).
When this determination (301) is NO, the process proceeds to determination (304) of whether the ionic current value is less than the release current set value. When this determination (301) is YES, the condensed water detection unit 29 determines that condensed water has been generated, substitutes “1” for the condensed water determination flag Wf (302), and the suppression control unit 30 determines the EGR permission flag Ef. “0” is substituted into (303).
When the suppression control unit 30 substitutes “0” for the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage section of the recirculation passage 18 becomes small, and the recirculation amount of the exhaust gas is normally set. Suppress than when controlling.
After suppressing the recirculation amount of the exhaust gas, the condensed water disappearance detection unit 31 determines whether or not the ionic current value is equal to or larger than the release current set value (304).
If this determination (304) is NO, this determination (304) is repeated. When this determination (304) is YES, the condensed water disappearance detection unit 31 determines that the condensed water has disappeared, substitutes “0” for the condensed water determination flag Wf (305), and the release control unit 32 performs the EGR permission flag. “1” is substituted into Ef (106), and the program is ended (307).
When the release control unit 32 assigns “1” to the EGR permission flag Ef, the control device 21 controls the EGR valve 20 so that the exhaust gas passage cross section of the reduced recirculation passage 18 returns to the original size, and the exhaust gas is discharged. The suppression control of the gas recirculation amount is canceled and normal control is resumed.

In this way, the exhaust gas recirculation device 16 of the internal combustion engine 1 suppresses the generation of condensed water by suppressing the recirculation amount of the exhaust gas when condensed water is generated, and then when the disappearance of the condensed water is detected, the exhaust gas Since the control for suppressing the recirculation amount of the exhaust gas can be released, the recirculation amount of the exhaust gas can be quickly restored after the disappearance of the condensed water. Therefore, after disappearance of the condensed water, exhaust gas can be sufficiently sent to the cylinder 7 and abnormal combustion of the internal combustion engine 1 can be quickly suppressed.
Further, the exhaust gas recirculation device 16 of the internal combustion engine 1 detects the disappearance of the condensed water based on the ionic current value indicating the combustion state in the cylinder 7 after the condensed water is detected. Since it can be confirmed that there is no influence, the exhaust gas recirculation amount can be restored at an appropriate time.

  The present invention is capable of promptly suppressing abnormal combustion of an internal combustion engine by sufficiently sending exhaust gas into a cylinder after the disappearance of condensed water. The present invention can be applied to a vehicle equipped with an internal combustion engine.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake passage 15 Exhaust passage 16 Exhaust gas recirculation device 17 Recirculation pipe 18 Recirculation passage 19 EGR cooler 20 EGR valve 21 Control device 22 Intake air amount sensor 23 Intake air temperature sensor 24 Crank angle sensor 25 Cam angle sensor 26 Water temperature sensor 27 Upstream side Exhaust sensor 28 Downstream exhaust sensor 29 Condensate detection unit 30 Suppression control unit 31 Condensate disappearance detection unit 32 Release control unit

Claims (4)

  An exhaust gas recirculation device that circulates exhaust gas of an internal combustion engine from an exhaust side to an intake side, wherein a condensed water detection unit that detects condensed water generated in a recirculation passage or an intake passage, and when the condensed water is detected, In the exhaust gas recirculation apparatus including a suppression control unit that suppresses the recirculation amount of the exhaust gas, after the condensed water is detected, a condensed water disappearance detection unit that detects the disappearance of the condensed water, and the disappearance of the condensed water An exhaust gas recirculation device for an internal combustion engine, comprising: a release control unit that cancels the suppression control when detected.   2. The exhaust gas recirculation of the internal combustion engine according to claim 1, wherein the condensed water disappearance detection unit detects disappearance of the condensed water based on a rotational speed of the internal combustion engine after the condensed water is detected. apparatus.   2. The exhaust gas recirculation apparatus for an internal combustion engine according to claim 1, wherein the condensed water disappearance detection unit detects disappearance of the condensed water based on an elapsed time from when the condensed water is detected.   2. The exhaust gas recirculation of the internal combustion engine according to claim 1, wherein the condensed water disappearance detecting unit detects disappearance of the condensed water based on an ion current value in a cylinder after the condensed water is detected. apparatus.

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