JP2020122463A - Regeneration device of egr cooler - Google Patents

Abstract

To optimally determine regeneration start timing.SOLUTION: A regeneration device of an EGR cooler 32 comprises an upstream temperature sensor 42 and a downstream temperature sensor 43 that respectively detect EGR gas temperatures T1 and T2 on the upstream and downstream sides of the EGR cooler, and a determination unit 100 that determines whether it is regeneration start timing based on the upstream gas temperature and the downstream gas temperature respectively detected by the upstream temperature sensor and the downstream temperature sensor.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to an EGR cooler regeneration device, and more particularly to a device for regenerating an EGR cooler provided in an internal combustion engine. Here, EGR (Exhaust Gas Recirculation) is an abbreviation for exhaust gas recirculation.

The internal combustion engine is provided with an EGR device for circulating EGR gas, which is a part of exhaust gas, toward the intake side. As a result, the temperature of the combustion gas in the cylinder can be lowered and the NOx emission amount can be reduced. An EGR cooler that cools the EGR gas to increase the gas density is also installed.

EGR gas, which is a part of exhaust gas, flows through the EGR cooler. Therefore, there is a problem that particulate matter (called PM (Particulate Matter)) such as soot contained in the EGR gas accumulates in the EGR cooler, and the cooling performance of the EGR cooler deteriorates.

Therefore, in the device described in Patent Document 1, the EGR cooler is regenerated by removing the accumulated PM to recover the cooling performance of the EGR cooler.

JP, 2013-160102, A

In the device described in Patent Document 1, the regeneration start condition is that the temperature of the exhaust gas passing through the EGR passage, that is, the EGR gas is lower than a predetermined temperature.

However, the temperature of the EGR gas changes according to the operating state of the internal combustion engine. Therefore, in the device described in Patent Document 1, there is room for improvement in the method of determining the regeneration start time.

Therefore, the present disclosure is devised in view of such circumstances, and an object thereof is to provide a regeneration device for an EGR cooler that can optimally determine the regeneration start time.

According to one aspect of the present disclosure,
A device for regenerating an EGR cooler provided in an internal combustion engine, comprising:
An upstream temperature sensor and a downstream temperature sensor for respectively detecting EGR gas temperatures on the upstream side and the downstream side of the EGR cooler;
Based on the upstream gas temperature and the downstream gas temperature respectively detected by the upstream temperature sensor and the downstream temperature sensor, a determination unit for determining whether or not the regeneration start time,
An EGR cooler regeneration device is provided.

Preferably, the determination unit determines whether or not it is the regeneration start time based on the difference or ratio between the upstream gas temperature and the downstream gas temperature.

Preferably, the determination unit compares the difference or the ratio with a predetermined threshold value to determine whether it is a regeneration start time, and also determines the value of the threshold value according to an operating state of the internal combustion engine.

Preferably, the regeneration device further includes a regeneration execution unit that performs regeneration of the EGR cooler when the determination unit determines that the regeneration start time is reached,
The regeneration executing unit increases the opening degree of the EGR valve when performing regeneration, and decreases the opening degree of the exhaust throttle valve compared to when regeneration is not performed.

Preferably, at the time of executing the reproduction, the reproduction executing unit executes the automatic reproduction if a predetermined automatic reproduction condition is satisfied, and executes the manual reproduction if the predetermined manual reproduction condition is satisfied.

According to the present disclosure, it is possible to optimally determine the reproduction start time.

1 is a schematic diagram showing a configuration of an embodiment of the present disclosure. 5 is a flowchart of a routine for calculating a basic target opening degree of an EGR valve. It is a figure which shows various maps. 7 is a flowchart of a reproduction control routine.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the embodiments below.

FIG. 1 is a schematic diagram showing a configuration of an embodiment of the present disclosure. The internal combustion engine (also called an engine) 1 is a multi-cylinder engine mounted on a vehicle (not shown). The vehicle is a large vehicle such as a truck, and the engine 1 is a multi-cylinder (specifically, in-line 4-cylinder) diesel engine. However, there are no particular limitations on the types, types, applications, etc. of the vehicle and the internal combustion engine. For example, the vehicle may be a small vehicle such as a passenger car, and the engine 1 may be a gasoline engine.

The engine may be mounted on a moving body other than a vehicle, such as a ship, a construction machine, or an industrial machine. Further, the engine does not have to be mounted on a moving body, and may be a stationary type engine for a generator or the like.

The vehicle according to the present embodiment is a so-called AMT (Automated Manual Transmission) vehicle in which the friction clutch CL and the manual transmission TM are operated by a clutch actuator and a shift actuator, respectively, to perform automatic gear shifting.

The engine 1 includes an engine body 2, an intake passage 3 and an exhaust passage 4 connected to the engine body 2, a turbocharger 14, and a fuel injection device 5. The engine body 2 includes structural parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts such as a piston, a crankshaft, and a valve that are housed inside.

The fuel injection device 5 is a common rail fuel injection device, and includes a fuel injection valve or injector 7 provided in each cylinder, and a common rail 8 connected to the injector 7. The injector 7 directly injects fuel into the cylinder 9, that is, into the combustion chamber. The common rail 8 stores the fuel injected from the injector 7 in a high pressure state.

The intake passage 3 is mainly defined by an intake manifold 10 connected to the engine body 2 (in particular, a cylinder head) and an intake pipe 11 connected to an upstream end of the intake manifold 10. The intake manifold 10 distributes and supplies the intake air sent from the intake pipe 11 to the intake ports of each cylinder. The intake pipe 11 is provided with an air cleaner 12, an air flow meter 13, a compressor 14C of a turbocharger 14, an intercooler 15, and an intake throttle valve 16 in this order from the upstream side. The air flow meter 13 is a sensor for detecting the amount of intake air per unit time of the engine 1, that is, the intake flow rate, and is also called a MAF sensor or the like.

The exhaust passage 4 is mainly defined by an exhaust manifold 20 connected to the engine body 2 (in particular, a cylinder head) and an exhaust pipe 21 arranged on the downstream side of the exhaust manifold 20. The exhaust manifold 20 collects the exhaust gas sent from the exhaust port of each cylinder. A turbine 14T of the turbocharger 14 is provided between the exhaust pipe 21 or between the exhaust manifold 20 and the exhaust pipe 21. The exhaust pipe 21 on the downstream side of the turbine 14T is provided with an exhaust throttle valve 6 and one or a plurality of post-treatment members (not shown) for purifying exhaust gas in order from the upstream side. The post-treatment member is formed of, for example, a filter that collects PM in exhaust gas or a selective reduction type NOx catalyst that removes NOx in exhaust gas.

The engine 1 includes an EGR device 30. The EGR device 30 includes an EGR passage 31 and an EGR passage 31 for recirculating a part of the exhaust gas in the exhaust passage 4 (in particular, the exhaust manifold 20), that is, EGR gas, into the intake passage 3 (in particular, the intake manifold 10). An EGR cooler 32 that cools the EGR gas flowing through and an EGR valve 33 that adjusts the flow rate of the EGR gas are provided. The EGR cooler 32 may be a water cooling type or an air cooling type. The EGR valve 33 is provided downstream of the EGR cooler 32 in the EGR gas flow direction.

Further, in the present embodiment, an electronic control unit (referred to as an ECU (Electronic Control Unit)) 100 that serves as a control unit, a circuit element, or a controller is provided. The ECU 100 controls the entire vehicle. The ECU 100 includes a CPU (Central Processing Unit) having an arithmetic function, a ROM (Read Only Memory) and a RAM (Random Access Memory) that are storage media, an input/output port, and a storage device other than the ROM and the RAM. The ECU 100 is configured and programmed to control the injector 7, the intake throttle valve 16, the exhaust throttle valve 6, the EGR valve 33, the clutch actuator and the shift actuator.

Further, in the present embodiment, as the sensors, in addition to the air flow meter 13 described above, a rotation speed sensor 40 for detecting the rotation speed of the engine (specifically, the number of rotations per minute (rpm)), and an accelerator opening. An accelerator opening degree sensor 41 for detecting the degree is provided. Further, an upstream temperature sensor 42 and a downstream temperature sensor 43 that detect the EGR gas temperatures T1 and T2 on the upstream side and the downstream side of the EGR cooler 32 are provided. The upstream temperature sensor 42 is provided on the inlet side of the EGR cooler 32 in the EGR passage 31. The downstream temperature sensor 43 is provided on the outlet side of the EGR cooler 32 in the EGR passage 31.

Further, a manual regeneration switch (SW) 44 and an exhaust brake switch 45 which are provided in the vehicle compartment and are turned on/off by a driver are provided. Further, a parking brake switch 46 is provided which is turned on/off according to whether the parking (P) brake is operated or not.

Next, the content of the control executed by the ECU 100 will be described. First, the basic control or normal control of the EGR valve 33 will be described.

The ECU 100 calculates the basic target opening degree Set of the EGR valve 33 according to the calculation routine shown in FIG. Then, normally, the target opening degree Se of the EGR valve 33 is set to a value equal to the basic target opening degree Set, and the opening degree of the EGR valve 33 is controlled so that the actual opening degree of the EGR valve 33 becomes equal to the target opening degree Se. .. The calculation routine of FIG. 2 is repeatedly executed by the ECU 100 at every predetermined calculation cycle τ (for example, 10 msec).

In step S101, the ECU 100 acquires the values of the engine speed Ne, the accelerator opening Ac, and the intake air amount Ga respectively detected by the rotation speed sensor 40, the accelerator opening sensor 41, and the air flow meter 13.

In step S102, the ECU 100 determines the fuel injection amount, specifically, the injector based on the engine speed Ne and the accelerator opening Ac according to a predetermined map (a function may be used. The same applies below) as shown in FIG. 3A. A target fuel injection amount Q is calculated as an instruction injection amount to the fuel cell No. 7.

The engine speed Ne, the accelerator opening Ac, and the target fuel injection amount Q are all engine parameters that represent the operating state of the engine. Further, the accelerator opening Ac and the target fuel injection amount Q are both engine parameters corresponding to the engine load.

Next, the ECU 100 calculates the basic target opening degree Set of the EGR valve 33 by executing steps S103 to S106. The basic target opening Set is obtained by adding the feedforward (F/F) term Seff and the feedback (F/B) term Sefb.

In step S103, the ECU 100 calculates the F/F term Seff based on the engine speed Ne and the target fuel injection amount Q according to a predetermined map as shown in FIG.

In step S104, the ECU 100 calculates the target intake air amount Gat based on the engine speed Ne and the target fuel injection amount Q according to a predetermined map as shown in FIG.

In step S105, the ECU 100 calculates the F/B term Sefb based on the difference between the target intake air amount Gat and the actual intake air amount Ga acquired in step S101. Specifically, the ECU 100 calculates a difference ΔGa=Gat−Ga between the target intake air amount Gat and the actual intake air amount Ga. Then, based on this difference ΔGa, the F/B term Sefb is calculated according to a predetermined map (not shown). When the difference ΔGa is positive, that is, when the actual intake air amount Ga is smaller than the target intake air amount Gat, the negative F/B term Sefb on the intake air amount increasing side, that is, the EGR gas amount decreasing side is calculated. On the contrary, when the difference ΔGa is negative, that is, when the actual intake air amount Ga is larger than the target intake air amount Gat, the positive F/B term Sefb on the intake air amount decreasing side, that is, the EGR gas amount increasing side is calculated. .. When calculating the F/B term Sefb, it is preferable that the total value of the P term, the I term, and the D term according to the difference ΔGa be the F/B term Sefb according to the PID control method.

At step S106, the ECU 100 calculates the EGR valve basic target opening Set (=Seff+Sefb) by adding the calculated F/F term Seff and F/B term Sefb.

In this way, the opening degree control of the EGR valve 33 is performed by a combination of the F/F control by the F/F term Seff and the F/B control by the F/B term Sefb. The F/F term Seff is a value that serves as a base of the EGR valve basic target opening degree Set, and is a value that can achieve a desired target EGR rate in the present engine operating state. On the other hand, the target EGR rate cannot always be realized only by the F/F term Seff because the actual engine operating state constantly changes. Therefore, the feedback term Sesb is added to precisely control the EGR valve opening so that the target EGR rate can be stably realized.

The opening degree of the EGR valve 33 is 100% when fully opened and 0% when fully closed. The same applies to the opening degrees of the intake throttle valve 16 and the exhaust throttle valve 6.

Next, the control of the exhaust throttle valve 6 will be described. The ECU 100 basically controls the exhaust throttle valve 6 to be fully open when the exhaust brake switch 45 is off, and controls the exhaust throttle valve 6 to have a smaller opening than full open, normally, fully closed when the exhaust brake switch 45 is on. To do. By reducing the opening degree of the exhaust throttle valve 6 in this manner, the exhaust pressure on the upstream side of the exhaust throttle valve 6 rises, which acts as resistance to increase the engine braking force, and the exhaust brake is operated.

Now, the EGR gas which is a part of exhaust gas flows through the EGR cooler 32. Therefore, there is a problem that particulate matter (PM) such as soot contained in the EGR gas is accumulated in the EGR cooler 32 and the cooling performance of the EGR cooler 32 is deteriorated.

Therefore, in the present embodiment, the regeneration is performed to remove the accumulated PM and restore the cooling performance of the EGR cooler 32. As a result, it is possible to suppress an increase in the temperature of the in-cylinder combustion gas due to insufficient cooling of the EGR gas and further an increase in NOx emission amount.

Particularly, in the present embodiment, based on the upstream gas temperature T1 detected by the upstream temperature sensor 42 and the downstream gas temperature T2 detected by the downstream temperature sensor 43, it is determined whether or not it is the timing to start the regeneration. That is, it is determined whether it is the reproduction start time.

The upstream gas temperature T1 and the downstream gas temperature T2 change according to the operating state of the engine, and tend to become higher toward the high rotation/high load side. Further, the value of the downstream gas temperature T2 with respect to the constant upstream gas temperature T1 changes depending on whether the cooling performance of the EGR cooler 32 is good or bad. The lower the cooling performance, the higher the temperature tends to approach the upstream gas temperature T1. is there. Therefore, by determining whether or not the regeneration start time is based on the upstream gas temperature T1 and the downstream gas temperature T2, it is possible to accurately determine whether the cooling performance of the EGR cooler 32 is good or bad while considering the operating state of the engine. It becomes possible to optimally determine the regeneration start time.

In the present embodiment, whether or not it is the regeneration start time is determined based on the difference dT=T1-T2 between the upstream gas temperature T1 and the downstream gas temperature T2. The difference dT=T1−T2 becomes smaller as the cooling performance of the EGR cooler 32 decreases when the engine operating state is constant. The difference dT is a suitable index value that correlates with the cooling performance of the EGR cooler 32. Therefore, it is possible to determine the reproduction start time optimally by determining whether or not the reproduction start time is based on the difference dT=T1-T2.

In the present embodiment, the difference dT is compared with a predetermined threshold value dTth to determine whether it is the regeneration start time, and the value of the threshold value dTth is determined according to the engine operating state.

Specifically, when the difference dT becomes smaller than the threshold value dTth, it is considered that the cooling performance of the EGR cooler 32 has decreased unacceptably, and it is determined that it is the regeneration start time. On the other hand, the value of the difference dT changes depending on both the engine operating state and the cooling performance of the EGR cooler 32. Therefore, even if the difference dTt becomes smaller than a certain threshold value regardless of the engine operating state, whether it is due to a change in the engine operating state or a decrease in the cooling performance of the EGR cooler 32 is discriminated. Can not do it.

In the present embodiment, the optimum threshold value dTth is determined according to the engine operating state. Therefore, by comparing this value with the difference dT, the influence of the change in the engine operating state is removed, and the cooling performance of the EGR cooler 32 is purely determined. You can judge the decline. This makes it possible to more accurately determine the reproduction start time.

As described above, the regeneration device for the EGR cooler 32 according to the present embodiment regenerates based on the upstream temperature sensor 42 and the downstream temperature sensor 43, and the upstream gas temperature T1 and the downstream gas temperature T2 detected by these sensors, respectively. And a determination unit that determines whether or not it is a start time. The determination unit is formed by the ECU 100.

The regeneration device for the EGR cooler 32 according to the present embodiment further includes a regeneration execution unit that performs regeneration of the EGR cooler 32 when the determination unit determines that the regeneration start time is reached. This regeneration executing unit is also formed by the ECU 100.

The ECU 100 increases the opening degree of the EGR valve 33 during regeneration, as compared to when the regeneration is not performed, and decreases the opening degree of the exhaust throttle valve 6 compared to when regeneration is not performed.

Normally, the opening degree of the EGR valve 33 is controlled to the target opening degree Se which is equal to the basic target opening degree Set according to the above-mentioned basic control. The same applies when reproduction is not executed. On the other hand, when the regeneration is executed, the opening degree of the EGR valve 33 is controlled to the target opening degree Se larger than the basic target opening degree Set. As a result, the flow rate of the EGR gas flowing through the EGR cooler 32 can be increased and the regeneration can be efficiently performed.

The target opening degree Se at this time is preferably fully open (=100%), but may be an intermediate opening degree smaller than full opening as long as it is larger than when the regeneration is not executed.

On the other hand, since the exhaust brake switch 45 is normally off, the opening degree of the exhaust throttle valve 6 is controlled to be fully open. The same applies when reproduction is not executed. On the other hand, at the time of executing the regeneration, the opening degree of the exhaust throttle valve 6 is controlled to be smaller than the full opening degree.

This makes it difficult for the exhaust gas to pass through the exhaust throttle valve 6, so that the flow rate of the EGR gas can be increased accordingly. Further, since the exhaust resistance increases and the engine speed tends to decrease, the target fuel injection amount Q is increased by, for example, further pressing the accelerator in order to maintain the same engine speed. As a result, the exhaust temperature, and eventually the EGR gas temperature, rises, and regeneration can be performed efficiently.

The opening degree at this time is preferably fully closed (=0%), but may be an intermediate opening degree larger than fully closed as long as it is smaller than when the regeneration is not executed.

As described above, when the regeneration is executed, by increasing the opening degree of the EGR valve 33 and decreasing the opening degree of the exhaust throttle valve 6, a large amount of high temperature EGR gas is caused to flow into the EGR cooler 32 and the PM accumulated on the EGR cooler 32 is accumulated. Can be efficiently burned and removed.

According to the present embodiment, since the regeneration is performed using the EGR valve 33 and the exhaust throttle valve 6 that are usually equipped in a large vehicle, it is possible to effectively utilize the existing configuration and perform cost reduction. It is advantageous. In the device of Patent Document 1, the EGR cooler is made of an electrothermal material and is regenerated by electrically heating the EGR cooler. Therefore, an EGR cooler of a special specification must be prepared, and an electric power is required at the time of regeneration. Has the drawback of being consumed.

At the time of executing the regeneration, the ECU 100 of the present embodiment executes the automatic regeneration if the predetermined automatic regeneration condition is satisfied, and executes the manual regeneration if the predetermined manual regeneration condition is satisfied. As a result, it is possible to select the optimum reproduction method according to the usage status of the vehicle. Note that the automatic regeneration is regeneration that is automatically started without the driver operating the manual regeneration switch 44. On the other hand, the manual regeneration is the regeneration started when the driver turns on the manual regeneration switch 44.

Next, the routine of the regeneration control of the EGR cooler 32 will be described with reference to FIG. The illustrated routine is repeatedly executed by the ECU 100 at every predetermined calculation cycle τ (for example, 10 msec).

First, in step S201, the upstream gas temperature T1 detected by the upstream temperature sensor 42, the downstream gas temperature T2 detected by the downstream temperature sensor 43, and the engine speed Ne detected by the rotation speed sensor 40. The value of the target fuel injection amount Q calculated in step S102 described above is acquired.

In step S202, the difference dT=T1-T2 between the upstream gas temperature T1 and the downstream gas temperature T2 is calculated.

In step S203, the difference threshold dTth is calculated based on the engine speed Ne and the target fuel injection amount Q according to a predetermined map as shown in FIG. In the map, the optimum threshold value dTth for detecting the deterioration of the cooling performance of the EGR cooler 32 is input for each combination of the engine speed Ne and the target fuel injection amount Q. Thereby, the optimum threshold value dTth according to the engine operating state can be calculated.

In step S204, the difference dT is compared with the threshold value dTth. When the difference dT is equal to or greater than the threshold value dTth, the cooling performance of the EGR cooler 32 has not deteriorated, and it is substantially determined that it is not the regeneration start time, and the routine is ended as it is.

On the other hand, when the difference dT is smaller than the threshold value dTth, the cooling performance of the EGR cooler 32 has deteriorated, and it is substantially determined that it is the regeneration start time, and the regeneration is appropriately executed after step S205. In this case, the driver is warned that the reproduction is necessary due to the deterioration of the cooling performance of the EGR cooler 32 using the information transmission device (monitor or the like) in the vehicle interior.

In step S205, it is determined whether a predetermined automatic regeneration condition is satisfied. The automatic regeneration condition is satisfied when the vehicle is traveling steadily at a relatively high predetermined vehicle speed (for example, 80 km/h) or more. This determination is made based on the detection value of a vehicle speed sensor (not shown).

If the automatic regeneration condition is satisfied, the process proceeds to step S206 and the automatic regeneration is executed. This is also notified to the driver by the information transmission device. In this way, the automatic regeneration is executed during high speed steady running of the vehicle.

During execution of automatic regeneration, the opening degree of the EGR valve 33 is controlled to be larger than that during non-execution of regeneration. Specifically, the opening degree of the EGR valve 33 is controlled to a target opening degree Se (=Set+ΔSe) equal to a value obtained by adding a predetermined additional opening degree ΔSe to the basic target opening degree Set. The additional opening degree ΔSe is set to an optimum opening degree so that the EGR cooler 32 can be supplied with as much EGR gas as possible while maximally satisfying the output request and the emission request.

Further, during execution of automatic regeneration, the opening degree of the exhaust throttle valve 6 is controlled to be smaller than that during non-execution of regeneration. Specifically, the opening degree of the exhaust throttle valve 6 is controlled to an intermediate opening degree Sx1 smaller than full opening when the exhaust brake switch 45 is off. The opening degree Sx1 is set to an optimum opening degree so that the EGR cooler 32 can be supplied with as much EGR gas as possible and the EGR gas temperature can be made as high as possible while maximally satisfying the output demand and the fuel consumption demand. ..

Note that when the exhaust brake switch 45 is on, the exhaust throttle valve 6 is controlled to be fully closed, and the vehicle is significantly decelerated. Therefore, the automatic regeneration condition is not normally established, and step S205 becomes NO. Therefore, it is not necessary to consider this case so much.

The automatic reproduction is ended when the execution time accumulated from the start of reproduction reaches a predetermined time. Alternatively, the automatic regeneration may be ended when the difference dT becomes equal to or larger than the threshold value dTth.

On the other hand, if the automatic regeneration condition is not satisfied in step S205, the process proceeds to step S207, and it is determined whether or not a predetermined manual regeneration condition is satisfied. The manual regeneration condition is satisfied when the manual regeneration switch 44 is turned on while the vehicle is idle. Idle stop means that at least one of clutch disengagement and transmission neutral is established (that is, the power transmission path is cut off), engine speed is idle speed, accelerator opening is fully closed, and parking brake switch 46 is A state in which all the conditions of ON (in operation) are satisfied.

If the manual regeneration condition is satisfied, the process proceeds to step S208, and the manual regeneration is executed. This is also notified to the driver by the information transmission device. Manual regeneration is performed while the vehicle is idle.

During manual regeneration, the opening of the EGR valve 33 is controlled to be larger than that during non-regeneration. Specifically, the opening degree of the EGR valve 33 is controlled to the target opening degree Se in the vicinity of the full opening. As a result, the EGR gas can be supplied to the EGR cooler 32 to the maximum extent.

Further, when the manual regeneration is executed, the opening degree of the exhaust throttle valve 6 is controlled to be smaller than that when the regeneration is not executed. Specifically, the opening degree of the exhaust throttle valve 6 is controlled to be fully closed or an opening degree Sx2 in the vicinity thereof. This opening degree Sx2 is smaller than the above-mentioned opening degree Sx1. As a result, the EGR gas can be supplied to the EGR cooler 32 to the maximum and the temperature can be increased. Since the exhaust brake switch 45 is normally off, it is not necessary to consider its state.

At the time of executing the manual regeneration, the idling speed may be made higher than usual to increase the flow rate of the EGR gas and further raise the temperature thereof.

Manual regeneration is also terminated when the execution time accumulated from the start of regeneration reaches a predetermined time. Alternatively, the manual regeneration may be terminated when the difference dT becomes equal to or larger than the threshold value dTth.

In step S207, if the manual regeneration condition is not satisfied, the routine is terminated and waits until either the automatic regeneration condition or the manual regeneration condition is satisfied.

Although the embodiments of the present disclosure have been described above in detail, various other embodiments of the present disclosure are possible.

(1) The ECU 100 may determine whether or not the regeneration start timing is based on the ratio rT=T1/T2 of the upstream gas temperature T1 and the downstream gas temperature T2. In this case, the reproduction control routine of FIG. 4 is modified as follows. That is, the ratio rT is calculated in step S202, the ratio threshold rTth is calculated in step S203, and it is determined in step S204 whether the ratio rT is smaller than the threshold rTth. When rT≧rTth, it is substantially determined that it is not the regeneration start time, and when rT<rTth, it is substantially determined that it is the regeneration start time.

(2) The vehicle may be a general automatic (AT (Automatic Transmission)) vehicle or a manual (MT (Manual Transmission)) vehicle rather than an AMT vehicle.

The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the concept of the present disclosure defined by the claims are included in the present disclosure. Therefore, the present disclosure should not be limitedly interpreted, and can be applied to any other technique belonging to the scope of the idea of the present disclosure.

1 Internal combustion engine (engine)
6 Exhaust Throttle Valve 32 EGR Cooler 33 EGR Valve 42 Upstream Temperature Sensor 43 Downstream Temperature Sensor 100 Electronic Control Unit (ECU)

Claims (5)

A device for regenerating an EGR cooler provided in an internal combustion engine, comprising:
An upstream temperature sensor and a downstream temperature sensor that detect EGR gas temperatures on the upstream side and the downstream side of the EGR cooler, respectively;
Based on the upstream gas temperature and the downstream gas temperature respectively detected by the upstream temperature sensor and the downstream temperature sensor, a determination unit that determines whether or not the regeneration start time,
An EGR cooler regeneration device characterized by being equipped with. The regeneration device for an EGR cooler according to claim 1, wherein the determination unit determines whether or not it is a regeneration start time based on a difference or a ratio between the upstream gas temperature and the downstream gas temperature. The determination unit compares the difference or the ratio with a predetermined threshold to determine whether it is a regeneration start time, and determines the value of the threshold according to an operating state of the internal combustion engine. EGR cooler regeneration device. When the determination unit determines that it is time to start regeneration, the EGR cooler further includes a regeneration execution unit that executes regeneration.
4. The regeneration executing unit increases the opening degree of the EGR valve when performing regeneration, as compared with when the regeneration is not performed, and decreases the opening degree of the exhaust throttle valve compared to when the regeneration is not performed. The EGR cooler regeneration device described in 1. The EGR cooler according to claim 4, wherein the regeneration executing unit performs automatic regeneration when a predetermined automatic regeneration condition is satisfied, and executes manual regeneration when a predetermined manual regeneration condition is satisfied, at the time of performing the regeneration. Playback device.

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