JP2003193896A - Exhaust gas circulating control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas circulating control device for an internal combustion engine, suppressing the amount of harmful material to be produced due to an increase of EGR gas and preventing the production of the harmful material due to lack of an intake air amount. <P>SOLUTION: During idling the engine 11 when a specified operated condition is established where a driver has no intention of immediately starting a vehicle, an EGR valve 23 is controlled to be open and a throttle valve 24 (25) is controlled to be closed. Thereby, a great amount of exhaust gas (EGR rate = 80-90%) is circulated into an intake pipe 13 to accurately reduce the amount of the harmful material such as NOx to be produced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas recirculation control device for an internal combustion engine, which circulates exhaust gas discharged from an exhaust system of an internal combustion engine such as a diesel engine into an intake system.

[0002]

2. Description of the Related Art For example, in a diesel engine, NO
In order to suppress the generation of x, an exhaust gas recirculation (EGR) device that circulates a part of the exhaust gas of the internal combustion engine in the intake system is applied. This EGR device connects an exhaust passage and an intake passage of an internal combustion engine with an EGR passage, and
An EGR valve is provided in the R passage, and the EGR valve is opened / closed according to the operating state of the internal combustion engine to return a predetermined amount of exhaust gas, that is, EGR gas, to the intake passage via the EGR passage. Since this EGR gas has a relatively high specific heat and can absorb a large amount of heat, the combustion temperature in the combustion chamber lowers as the circulation amount of the EGR gas increases, and NOx of NOx increases as the combustion temperature decreases. The amount generated can be reduced.

As such an EGR device, for example,
It is described in Japanese Patent Application Laid-Open Nos. 7-019126 and 20-145505.

[0004]

In the above-mentioned conventional diesel engine, it is said that when the circulation amount of EGR gas is increased in a low load and low rotation state such as idling operation, the NOx generation amount is greatly reduced. However, when the circulation amount of EGR gas is increased in the low load and low rotation state of the diesel engine, the amount of NOx generated is reduced. Therefore, the output will be insufficient, and the amount of black smoke generated will increase due to poor combustion. This phenomenon is remarkable in diesel engines equipped with a supercharger.

That is, when the diesel engine is in a low load and low rotation state, the intake air amount and the total exhaust gas flow rate are small, and the supercharger does not operate sufficiently, resulting in a low supercharging pressure. When the accelerator opening is increased from the state, the fuel injection amount is increased, the pressure and temperature on the upstream side of the turbine are increased, the pressure difference between the intake pressure and the exhaust pressure is increased, and the EGR gas amount is increased, while the supercharger is increased. The rotation speed increases and the intake air amount increases, but since there is a time delay (turbo lag) in the increase of the turbocharger rotation speed, EGR is temporarily higher than the intake air amount.
The amount of gas increases, and the excess air ratio in the combustion chamber becomes insufficient, causing a large amount of black smoke.

The present invention is intended to solve such a problem, and it is possible to suppress the amount of harmful substances generated by increasing the EGR gas and prevent the generation of harmful substances due to insufficient intake air amount. It is an object of the present invention to provide an exhaust gas recirculation control device of

[0007]

In the exhaust gas recirculation control device for an internal combustion engine according to the invention of claim 1 for achieving the above object, an EGR valve is provided in an EGR passage communicating an exhaust system and an intake system of the internal combustion engine. In addition, a throttle valve is provided in the exhaust system downstream of the connection between the exhaust system and the EGR passage or in the intake system upstream of the connection between the intake system and the EGR passage. When it is determined that the vehicle is in the specific operating state, the control means controls the EGR valve to the valve opening side and the throttle valve to the valve closing side when it is determined that the vehicle is in the specific operating state. .

Therefore, if it is determined that the internal combustion engine is in the specific operating state during idling, the EGR valve is controlled to the opening side and the throttle valve is controlled to the closing side. The amount of exhaust gas that circulates through the passage increases and the EGR rate increases, so that the amount of harmful substances such as NOx can be reduced, while the internal combustion engine is not idling even when idling. At times, since this control is not performed, a large amount of exhaust gas does not circulate in the intake system, and it is possible to prevent generation of harmful substances such as black smoke due to insufficient intake air amount.

In the exhaust gas recirculation control device for an internal combustion engine according to the second aspect of the present invention, this specific operating state is an operating state in which idling of the internal combustion engine continues for a predetermined period. Therefore,
In an operating state where the idling of the internal combustion engine continues for a predetermined period of time, the driver does not intend to immediately start the vehicle and performs the above control to circulate a large amount of exhaust gas in the intake system to generate the amount of harmful substances. Can be effectively reduced.

In this case, the operating state in which the idling of the internal combustion engine continues for a predetermined period is preferably, for example, the following operating state. Driving state where the accelerator pedal is not depressed and the parking brake lever is in the operating state in the idling state.In the idling state, the accelerator pedal and the clutch pedal are not depressed and the transmission is in the neutral position. In idle mode, the accelerator pedal is not depressed and the idle stop cancel switch is operated.

The conditions (1) to (3) for canceling the specific operating states of the internal combustion engine are preferably as follows. Release the parking brake lever Press the clutch pedal Release the cancel switch of the idle stop function,
Either releasing the parking brake lever or depressing the clutch pedal.

In the exhaust gas recirculation control device for an internal combustion engine according to a third aspect of the present invention, the control means controls the control parameter relating to the fuel injection so that the combustion of the internal combustion engine is stable when it is determined that the engine is in the specific operating state. I am trying to do it. Therefore, while the internal combustion engine is idling in a specific operating state, a large amount of exhaust gas is circulated in the intake system to suppress the amount of harmful substances generated, while controlling the control parameters related to fuel injection so that combustion is stabilized. , Deterioration of fuel efficiency and HC, C
Generation of harmful substances such as O and particulates can be suppressed.

When the fuel injection control parameter is the fuel injection timing, it is preferable to control the fuel injection timing to the advance side so that the intake air and the injected fuel are properly mixed and the cylinder temperature and the cylinder pressure are controlled. Rises and self-ignition becomes easier. Further, when the control parameter for fuel injection is the fuel injection pressure, it is preferable to control this fuel injection pressure to the high pressure side, and the injected fuel of this high pressure is atomized early and is likely to self-ignite.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic configuration of an exhaust gas recirculation control device for an internal combustion engine according to a first embodiment of the present invention, and FIG. 2 is a control diagram for determining a specific operating state by the exhaust gas recirculation control device for an internal combustion engine according to the present embodiment. A flowchart and FIG. 3 show a flowchart of EGR control by the exhaust gas recirculation control device for an internal combustion engine of the present embodiment.

In the exhaust gas recirculation control system for an internal combustion engine of this embodiment, as shown in FIG. 1, a diesel engine 11 as an internal combustion engine has an intake pipe through an intake manifold 12 to an intake port facing a combustion chamber (not shown). 13 is connected, an air cleaner 14 is attached to the air intake of the intake pipe 13, and an intercooler 15 is attached midway. On the other hand, the exhaust pipe 17 is connected to the exhaust port (not shown) of the engine 11 via the exhaust manifold 16.
Are connected.

The engine 11 is also provided with a turbocharger 18. The turbocharger 18 is configured by coaxially connecting a compressor 19 provided in the intake pipe 13 and a turbine 20 provided in the exhaust pipe 17. A particulate filter 21 that collects fine particles (PM: particulate matter, harmful substances such as black smoke) in the exhaust gas is provided downstream of the turbine 20 of the turbocharger 18 in the exhaust pipe 17. ing. The EGR passage 2 for circulating exhaust gas to the intake pipe 13 is provided between the exhaust pipe 17 downstream of the turbine 20 of the turbocharger 18 and the intake pipe 13 upstream of the compressor 19.
2 is provided, and an EGR valve 23 is provided in the EGR passage 22. The EGR passage 22 may be provided between the exhaust pipe 17 upstream of the turbine 20 and the intake pipe 13 downstream of the compressor 19.

Further, in the intake pipe 13, a throttle valve 24 for adjusting the intake pressure is provided on the upstream side of the connection between the intake pipe 13 and the EGR passage 22. The throttle valve 24 is for adjusting the EGR circulation amount by changing the opening / closing amount according to the operating state of the engine 11. Instead of the throttle valve 24, the exhaust pipe 17 is used to control the exhaust gas. A throttle valve 25 for adjusting the exhaust pressure may be provided downstream of the connecting portion between the pipe 17 and the EGR passage 22.

On the other hand, an input / output device and a storage device (R
OM, RAM, non-volatile RAM, etc., central processing unit (C
An ECU (electronic control unit) 26 having a PU), a timer counter, etc. is provided.
By 6 the overall control including the engine 11 is performed. That is, the engine speed sensor 27, the parking brake switch 28, the accelerator opening sensor 29, etc. are connected to the input side of the ECU 26, and the detection information from these sensors is input. On the other hand, an injector driver 30 or the like (not shown) is connected to the output side of the ECU 26, and the injector driver 30 or the like is connected to the injector driver 30 or the like based on the detection information from various sensors. The optimum value of is output. Furthermore,
An EG for opening and closing the EGR passage 22 is provided on the output side of the ECU 26.
Throttle valve 24 (25) for opening and closing the R valve 23 and the intake pipe 13
Are connected and controlled to be opened / closed in accordance with the operating state of the engine.

In the exhaust gas recirculation control device for an internal combustion engine of the present embodiment as described above, the ECU 26 determines whether the engine 11 is in a specific operating state during idling (operating state determining means), and determines the specific state. When it is determined that the engine is in the operating state, the EGR valve 23 is controlled to be opened and the throttle valve 24 (25) is controlled to be closed (control means). That is, E in the specific driving state during idling
When the GR valve 23 is opened and the throttle valve 24 (25) is closed, the amount of exhaust gas circulated to the intake pipe 13 via the EGR passage 22 with respect to the intake air amount increases and the EGR rate increases. Therefore, the amount of harmful substances such as NOx generated can be reduced. On the other hand, when the engine 11 is not idling even when the engine 11 is idling, a large amount of exhaust gas does not circulate in the intake pipe 13 because this control is not performed, and harmful substances such as black smoke due to insufficient intake air amount. Can be prevented.

The specific operating state is preferably an operating state in which the idling of the engine 11 continues for a predetermined period. In this operating state, the driver does not intend to immediately start the vehicle and performs the above control. Therefore, it is possible to reliably reduce the amount of NOx generated due to the circulation of the EGR gas and to reliably prevent the generation of black smoke due to the shortage of the intake air amount. The determination of the operating state in which the idling of the engine 11 continues for a predetermined period will be described later, but the accelerator pedal depression, the parking brake lever operation, the clutch pedal depression, the transmission operating position, and the idle stop function cancel switch are determined. It is desirable to do it by operation.

Further, the ECU 26 controls the fuel injection control parameter so that the combustion of the engine 11 becomes stable when it is determined that the vehicle is in the specific operating state, and the deterioration of fuel consumption, HC, CO, particulates, etc. It is possible to suppress the generation of harmful substances. In this case, when the control parameter for fuel injection is the fuel injection timing, the intake air and the injected fuel are properly mixed by controlling the fuel injection timing to the advance side, and the cylinder temperature and the cylinder pressure are increased. It becomes easier to self-ignite. Further, when the fuel injection pressure is used as the control parameter related to the fuel injection, if the fuel injection pressure is controlled to the high pressure side, the high pressure injected fuel will be atomized early and easily self-ignited.

Now, the determination control and the EGR control of the specific operation state by the exhaust gas recirculation control device of this embodiment will be specifically described.

In the determination control of the specific operating state of the engine 11, as shown in FIG. 2, in step S1, the ECU
26 reads various sensors, and in step S2,
The operation of the parking brake lever is determined by the ON / OFF signal of the parking brake switch 28. In step S2, the driver turns off the parking brake switch 28 without operating the parking brake lever.
When the FF signal is output, the process proceeds to step S7,
Assuming that the engine 11 is not in the specific operation state, LI (Long
Idling) flag = 0, and exits this routine without doing anything.

On the other hand, when the driver actuates the parking brake lever to output the ON signal from the parking brake switch 28 in step S2, the process proceeds to step S3, in which the detection result of the engine speed sensor 27 is detected. Based on this, it is determined whether the engine speed Ne is less than or equal to the predetermined engine speed Ne ₀ . The predetermined engine speed Ne ₀ is, for example, an idling speed, and if the engine speed Ne is less than or equal to the idling speed Ne ₀ , the process proceeds to step S4, and the engine speed Ne is
If is greater than the idling speed Ne ₀ , nothing is done and the routine exits.

In step S4, the accelerator opening sensor 2
Based on the detection result of No. 9, the accelerator opening degree θ is a predetermined value θ ₀
It is determined whether or not the following. The predetermined value θ ₀ is, for example, 0, and it is detected that the driver has not depressed the accelerator pedal, and if the accelerator opening θ is 0, the process proceeds to step S5, and if the accelerator opening θ is larger than 0. , Exit this routine without doing anything.

In step S5, when the driver actuates the parking brake lever and the ON signal is output from the parking brake switch 28, the process proceeds to step S6, in which it is determined that the engine 11 is in the specific operation state.
While the (Long Idling) flag is set to 1, when the parking brake switch 28 outputs an OFF signal,
Exit this routine without doing anything.

As described above, in steps S2 to S4, when it is determined that the parking brake lever is operated, the engine speed Ne is the idle speed, and the accelerator pedal is not depressed, the engine 11 is operated in a specific operation mode. When the parking brake lever is released in step S5, it is determined that the specific operation state of the engine 11 is released.

When the specific operating state of the engine 11 is determined, the EGR control is performed based on this determination result. This E
In the GR control, as shown in FIG. 3, step S11
At step S12, the ECU 26 reads various sensors, and at step S12, the specific operation state of the engine 11 is determined. That is, in step S12, it is determined whether or not the LI flag = 1. If the LI flag = 1, it is determined that the specific operation state is set, and then the large-volume EGR control is executed in step S13 and thereafter.

That is, in step S13, the ECU 26 controls the EGR valve 23 to the valve opening side and the throttle valve 24 (2
5) is controlled to the valve closing side, the fuel injection timing is controlled to the advance side in step S14, and the fuel injection pressure is controlled to the high pressure side in step S15. That is, when the opening degree of the EGR valve 23 is increased and the closing degree of the throttle valve 24 (25) is increased, the amount of exhaust gas is easily introduced into the intake pipe 13, and the intake pipe 13 has a larger amount of intake air than the intake air amount. As a result, the amount of exhaust gas circulated as a result is significantly increased to increase the EGR rate, and the amount of harmful substances such as NOx generated can be reduced. Further, when the fuel injection timing is advanced, the intake air and the injected fuel are properly mixed, the cylinder temperature and the cylinder pressure are increased, and the self-ignition easily occurs. Furthermore, when the fuel injection pressure is set to a high pressure, the fuel injected at a high pressure is atomized at an early stage and is likely to self-ignite. Therefore, it is possible to suppress deterioration of fuel efficiency and generation of harmful substances such as HC, CO, and particulates.

On the other hand, if it is determined in step S12 that the LI flag = 0 and it is not in the specific operation state, step S12
Normal EGR control is executed after 16. That is, in step S16, the ECU 26 controls the opening / closing of the EGR valve 23 and the throttle valve 24 (25) according to the operating state, and the step S16
At 17, the fuel injection timing is controlled according to the operating condition, and at step S18, the fuel injection pressure is controlled according to the operating condition. In other words, when the engine 11 is idling and is not in the specific operation state, a large amount of exhaust gas is not circulated in the intake pipe 13, so that a shortage of intake air amount occurs due to the circulation of a large amount of exhaust gas in the intake pipe 13. Therefore, it is possible to prevent the generation of harmful substances such as black smoke due to the insufficient intake air amount.

Thus, in this embodiment, the engine 11
When the driver is in a specific driving state in which the driver does not intend to immediately start the vehicle while idling, the EGR valve 23
By controlling the throttle valve 24 (25) to the valve closing side and controlling the throttle valve 24 (25) to the valve closing side, a large amount of exhaust gas (for example, EGR rate = 80 to 90%) is circulated in the intake pipe 13 and NOx and the like The amount of harmful substances generated can be accurately reduced. On the other hand, in a driving state in which the driver intends to start the vehicle even when the engine 11 is idling, a large amount of exhaust gas circulates in the intake pipe 13 in order to perform EGR control according to the driving state. Even if the driver depresses the accelerator pedal to accelerate, black smoke does not occur due to insufficient intake air amount.

FIG. 4 is a flow chart of the control for determining the specific operation state by the exhaust gas recirculation control device for an internal combustion engine according to the second embodiment of the present invention, and FIG. 5 is the exhaust gas for the internal combustion engine according to the third embodiment of the present invention. The flowchart of the specific operation state determination control by a recirculation | reflux controller is shown. It should be noted that members having the same functions as those described in the above-described embodiment are designated by the same reference numerals, and redundant description will be omitted.

In the exhaust gas recirculation control system for an internal combustion engine according to the second embodiment, as shown in FIG. 1, the idle stop function cancel switch 33 is provided on the input side of the ECU 26 in addition to the sensors of the above-mentioned respective embodiments. Are connected, and the detection information from these sensors is input. The idle stop function cancel switch (hereinafter referred to as a cancel switch) 33 is a switch operated when the idle stop function of automatically stopping the engine 11 when the vehicle is stopped is not executed from the viewpoint of cooling and heating.

When the cancel switch 33 is operated, it is determined that the driver has no intention of starting the vehicle and the load variation of the engine 11 is less likely to occur, and the driver is more likely than the specific driving described above. The throttle degree of the throttle valve 24 (24) and / or the EGR valve 23 may be largely controlled so that the EGR rate increases. Further, in this case, it is possible to reduce the exhaust gas amount to about 1/10 (EGR rate-90%) as compared with idling without EGR.

Therefore, in the determination control of the specific operation state of the engine 11, as shown in FIG. 4, the ECU 26 reads various sensors in step S31, and in step S32, an OFF signal of the cancel switch 33, The output of the OFF signal of the parking brake switch 28 and the OFF signal of the clutch pedal switch 32 is determined, and when the OFF signal is output from at least one of the switches 33, 28, 32, the process proceeds to step S37 and the engine is operated. Since 11 is not in the specific operation state, the LI flag is set to 0, and this routine is exited.

On the other hand, in step S32, each switch 3
When the ON signals are output from all 3, 28, 32, the process proceeds to step S33. And step S2
3, the engine speed Ne is equal to or lower than a predetermined engine speed (for example, idling speed) Ne ₀ , and step S3
If the accelerator opening θ is equal to or smaller than the predetermined value θ ₀ (= 0) in step 4, the process proceeds to step S25, and if not, the routine is exited without doing anything. Then, in step S35,
When the driver operates the cancel switch 33 to output the ON signal, in step S36, the engine 11
Is in a specific operation state, the LI flag is set to 1, while the driver operates the cancel switch 33 to perform OF.
When the F signal is output, the routine is exited without doing anything.

Thus, in steps S32 to S34,
When the cancel switch 33 is turned on, the engine speed Ne is the idle speed, and the clutch pedal and the accelerator pedal are not depressed, the engine 11
Is determined to be the specific operation state, and in step S35,
When the cancel switch 33 is turned off, the cancellation of the specific operating state of the engine 11 is determined. Then, when the specific operation state of the engine 11 is determined, the EGR control is performed based on the determination result as in the above-described embodiment. Therefore, it is possible to reliably determine the specific driving state in which the driver does not intend to start the vehicle and execute the appropriate EGR control. In step S37, the idle stop function cancel switch 33 may be automatically turned off when switching from the LI flag = 1 to the LI flag = 0.

In the exhaust gas recirculation control device for an internal combustion engine according to the third embodiment, as shown in FIG. 1, on the input side of the ECU 26, in addition to the sensors of the above-described respective embodiments, a transmission (T / M) is provided. ) A shift position detection sensor 34 for detecting the operation position is connected, and detection information from these sensors is input.

Therefore, in the determination control of the specific operating state of the engine 11, as shown in FIG. 5, the ECU 26 reads various sensors in step S41, and the clutch pedal switch 32 is turned off in step S42.
When the output of the signal is determined and the clutch pedal is depressed and the OFF signal is output from the switch 32, the process proceeds to step S51 and the duration t of the specific operation state is set to 0.
(Reset), and the LI flag is set to 0 in step S52 on the assumption that the engine 11 is not in the specific operation state.

On the other hand, when the ON signal is output from the switch 32 without depressing the clutch pedal in step S42, the process proceeds to step S43. Then, the shift position detection sensor 34 detects the neutral position of the shift position in step S43, the ON signal is output from the clutch pedal switch 32 in step S44, and the step S4
When the accelerator opening θ is equal to or less than the predetermined value θ ₀ (= 0) in 5 and the engine speed Ne is equal to or less than the predetermined engine speed (for example, idling speed) Ne ₀ in step S46, the process proceeds to step S47, and the specific operation is performed. The duration t of the state is added, otherwise the duration t is set to 0. In step S87, the duration t of the particular operating condition it is determined whether or not has reached a predetermined time t ₀ or more, the duration t of a particular operating condition is equal to the predetermined time t ₀ or more, step S4
At 9, while assuming that the engine 11 is in the specific operation state, the LI flag is set to 1, while if the duration t of the specific operation state has not reached the predetermined time t ₀ , nothing is done and the routine exits.

Thus, in steps S42 to S46,
When the clutch pedal and the accelerator pedal are not depressed, the shift position of the transmission is in the neutral position, and the engine speed Ne is the idle speed, it is determined that the engine 11 is in the specific operation state, and step S4 is performed.
When the clutch pedal is depressed at 4, the engine 1
The cancellation of the specific operation state 1 is determined. Then, when the specific operation state of the engine 11 is determined, the EGR control is performed based on the determination result as in the above-described embodiment. Therefore, it is possible to reliably determine the specific driving state in which the driver does not intend to start the vehicle and execute the appropriate EGR control.

In each of the above-described embodiments, the determination of the specific operating state during idling of the engine 11 is performed by depressing the accelerator pedal (accelerator opening sensor 29), operating the parking brake lever (parking brake switch 28), It is performed by depressing the clutch pedal (clutch pedal switch), operating position of the transmission (shift position detection sensor 34), and cancel switch 33 of the idle stop function, but the combination of these is not limited to the embodiment, and , Another sensor or switch may be used.

[0044]

As described above in detail in the embodiment, according to the exhaust gas recirculation control device for an internal combustion engine of the invention of claim 1, the operating condition determining means is in a specific operating condition while the internal combustion engine is idling. Whether the internal combustion engine is idling because the control means controls the EGR valve to the opening side and closes the throttle valve side when it is determined to be in this specific operating state. If it is determined that the engine is operating, the EGR valve is controlled to open and the throttle valve is controlled to close.
The amount of exhaust gas circulating through the GR passage increases and the EGR
As a result, the amount of harmful substances such as NOx can be reduced, while the internal combustion engine is not idling even when idling, a large amount of exhaust gas is generated because this control is not performed. Since it does not circulate in the intake system, it is possible to prevent generation of harmful substances such as black smoke due to insufficient intake air amount.

According to the exhaust gas recirculation control device for an internal combustion engine of the second aspect of the invention, the specific operating state is set to the operating state in which the idling of the internal combustion engine continues for a predetermined period, so the operation in which the idling of the internal combustion engine continues for a predetermined period. In the state, the driver does not intend to immediately start the vehicle, and the above control is performed, so that a large amount of exhaust gas is circulated in the intake system, and thus the amount of harmful substances generated can be effectively reduced.

According to the exhaust gas recirculation control device for an internal combustion engine of the third aspect of the invention, the control means sets the control parameter for fuel injection to stabilize the combustion of the internal combustion engine when it is determined that the engine is in the specific operating state. Since the internal combustion engine is idling in a specific operation state, a large amount of exhaust gas is circulated in the intake system to suppress the generation of harmful substances.
Since the control parameters related to fuel injection are controlled so that combustion is stable, it is possible to suppress deterioration of fuel consumption and generation of harmful substances such as HC, CO, and particulates.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an exhaust gas recirculation control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a flowchart of determination control of a specific operation state by the exhaust gas recirculation control device for an internal combustion engine according to the first embodiment.

FIG. 3 is a flowchart of EGR control by an exhaust gas recirculation control device for an internal combustion engine according to the first embodiment.

FIG. 4 is a flowchart of determination control of a specific operating state by an exhaust gas recirculation control device for an internal combustion engine according to a second embodiment.

FIG. 5 is a flowchart of determination control of a specific operating state by an exhaust gas recirculation control device for an internal combustion engine according to a third embodiment.

[Explanation of symbols]

11 Diesel engine (internal combustion engine) 13 Exhaust pipe 17 Exhaust pipe 18 Turbocharger 22 EGR passage 23 EGR valve 24 Throttle valve 25 Throttle valve 26 ECU, electronic control unit (operating state determination means, control means) 27 Engine speed sensor 28 Parking Brake Switch 29 Accelerator Opening Sensor 32 Clutch Pedal Switch Switch 33 Cancel Switch 34 Shift Position Detection Sensor

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/02 310 F02D 41/02 310E 41/16 41/16 GP 41/30 41/30 F02M 25 / 07 550 F02M 25/07 550K 550R F term (reference) 3G062 AA01 AA05 BA04 BA06 CA00 CA03 DA01 EA10 3G065 AA01 AA03 AA10 CA12 EA03 GA10 GA14 GA28 GA29 GA41 GA46 FA03 FA10 ECB FA16 BA10 BA16 BA10 BA10 BA11 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA19 BA10 BA11 BA19 BA19 FA36 3G092 AA02 AA17 AA18 AB03 BA02 BB01 BB06 DB03 DC02 DC10 DC12 DE01S DF01 DF02 DG10 EA01 EA11 EA14 EA17 EC03 FA17 FA18 GA04 HA06Z HB01X HB02 JA11 HA11 NA12 HA11 JA12 HA11 HA12HA11 HA12HA11 HA12ZHA11HA12 HA12G HAZXHA01X25 HA11ZAHA25HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA25HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA14HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA11HA12HA14HA11HA12 NE13 NE24 PA11Z PE01Z PF03Z PF05Z PF06Z PF07Z PF16Z

Claims (3)

[Claims] 1. An EGR valve provided in an EGR passage that connects an exhaust system and an intake system of an internal combustion engine, and the exhaust system or the intake system downstream of a connecting portion between the exhaust system and the EGR passage. The throttle valve provided in the intake system upstream of the connection with the EGR passage, the operating state determining means for determining whether the internal combustion engine is in the specific operating state during idling, and the operating state determining means Exhaust gas recirculation of an internal combustion engine, comprising: a control means for controlling the EGR valve to the valve opening side and the throttle valve to the valve closing side when it is determined that the engine is in the specific operation state. Control device. 2. The exhaust gas recirculation control device for an internal combustion engine according to claim 1, wherein the specific operation state is an operation state in which idling of the internal combustion engine continues for a predetermined period. 3. The control device according to claim 1, wherein the control means controls a control parameter relating to fuel injection so that combustion of the internal combustion engine is stable when it is determined that the engine is in the specific operating state. Exhaust gas recirculation control device for internal combustion engine.