JP5825707B2 - EGR device - Google Patents

Description

  The present invention relates to an EGR (exhaust gas recirculation) device that recirculates a part of exhaust gas from a combustion device such as an internal combustion engine into a combustion chamber for recombustion.

  Purifying the exhaust from the internal combustion engine to suppress the expansion of air pollution is an important issue, but as one of the systems (apparatus) for this purpose, a part of the exhaust from the internal combustion engine is returned to the combustion chamber. A so-called EGR (Exhaust Gas Recirculation) system is known for reducing the combustion temperature by reducing the combustion temperature and reducing the concentration (exhaust amount) of nitrogen oxide (hereinafter referred to as NOx) in the exhaust gas. ing.

  In such an EGR system, by cooling the EGR gas to be recirculated into the combustion chamber, the combustion temperature can be lowered, and thereby the NOx emission can be more effectively reduced.

  For this reason, for example, in the EGR system described in Patent Document 1, an EGR cooler that is a heat exchanger for cooling EGR gas is connected to an EGR passage that guides the EGR gas from the exhaust passage to the intake passage of the internal combustion engine. It has been done to intervene.

  In addition, since the expansion of the EGR gas is suppressed by providing the EGR cooler and lowering the EGR gas temperature, it is desired to increase the amount of EGR gas (exhaust gas recirculation amount) mixed in the intake air, that is, the EGR rate (= EGR This is also advantageous when there is a demand for further earning gas amount / (fresh air amount + EGR gas amount) × 100 (%)).

  Here, as a means for achieving further NOx reduction, it is conceivable to further cool the EGR gas. For example, the EGR gas is cooled from about 150 ° C. to 100 ° C. or less. In such a case, there is a high possibility that condensed water is generated from the cooled EGR gas.

  Since the EGR gas contains sulfur in the fuel, the condensed water contains sulfuric acid. Therefore, if the condensed water containing sulfuric acid adheres to or stays inside the EGR passage or the combustion chamber of the internal combustion engine, the internal combustion engine Corrosion, damage, etc. will be caused in each part of the engine (EGR passage, EGR valve, intake passage, combustion chamber, etc.). Furthermore, the combustion chamber of the internal combustion engine may suck in the parts (foreign matters) that have been corroded and peeled off. In such a case, the internal combustion engine may be damaged.

  In addition, since the combustion chamber of the internal combustion engine sucks in a large amount of condensed water, the internal combustion engine may be damaged by a so-called water hammer.

  As a technique for suppressing such a fear, for example, in Patent Document 1, a foreign matter collecting device is interposed downstream of the EGR cooler, and condensed water adhering to the net is dropped downward by gravity and further adsorbed. What is made to adsorb | suck to an agent is described.

JP 2010-151091 A

  However, since the thing of patent document 1 is only for the purpose of collecting the generated condensed water, there exists a possibility that it may not be enough with respect to corrosion, damage, etc. of each part of the internal combustion engine resulting from condensed water. .

  In other words, the inventors have conducted various experiments and researches, and as a result of repeated examinations, it is important to collect the generated condensed water. However, the corrosion and damage of each part of the internal combustion engine caused by the condensed water are more serious. In order to effectively suppress the condensed water, it is effective if it is configured to collect the condensed water and evaporate the collected condensed water, and further to prevent the condensed water from being generated. I got new knowledge.

  The present invention has been made in view of such circumstances, and condensate generated with cooling of the EGR gas is collected by the condensed water collecting means and the condensed water collecting means while having a simple and inexpensive configuration. Condensed water that collided with the engine can be evaporated, and by creating an environment in which condensed water is unlikely to be generated, corrosion, damage, etc. of each part of the internal combustion engine caused by condensed water can be effectively suppressed. An object of the present invention is to provide an EGR device that can be used.

For this reason, the present invention
An EGR device that recirculates a part of exhaust gas as EGR gas to a combustion chamber through an EGR passage,
Condensed water collecting means for collecting condensed water from EGR gas flowing in the EGR passage;
A condensed water recovery tank for recovering the condensed water collected by the condensed water collecting means;
Heating means for heating the condensed water collecting means to evaporate the condensed water nearby;
Comprising
The condensed water collecting means is constituted by a condensed water collecting plate which is a metal mesh element having a plurality of openings,
The condensate collecting plate is disposed in the EGR passage on the downstream side of the EGR cooler along the direction intersecting the EGR gas flow, and the lower end side of the condensate collecting plate is arranged with respect to the upper end side. And inclined so as to be located downstream of the EGR gas flow,
A communication passage to the condensed water recovery tank is provided on the downstream side of the EGR gas flow at the lower end of the condensed water collecting plate .

The present invention also provides:
An EGR device that recirculates a part of exhaust gas as EGR gas to a combustion chamber through an EGR passage,
Condensed water collecting means for collecting condensed water from EGR gas flowing in the EGR passage;
A condensed water recovery tank for recovering the condensed water collected by the condensed water collecting means;
Heating means for heating the condensed water collecting means to evaporate the condensed water nearby;
Comprising
The condensed water collecting means is constituted by a condensed water collecting plate which is a metal mesh element having a plurality of openings,
The condensate collecting plate is disposed in the EGR passage on the downstream side of the EGR cooler along the direction intersecting the EGR gas flow, and the lower end side of the condensate collecting plate is arranged with respect to the upper end side. And inclined so as to be located downstream of the EGR gas flow,
A lower end of the condensed water collecting plate is disposed so as to overlap with an opening portion of a communication passage to the condensed water recovery tank .

In the present invention, the heating means can be a means for energizing and heating the condensed water collecting plate .

In the present invention, while the EGR gas temperature for heating the condensed water collecting plate by the heating means below a predetermined temperature, when the EGR gas temperature is higher than the predetermined temperature of the condensed water collecting plate by the heating means It can be characterized by not heating.

  In the present invention, the amount of cooling medium of the EGR cooler is controlled in accordance with the operating state of the internal combustion engine so that the EGR gas temperature on the outlet side of the EGR cooler becomes higher than the acid dew point temperature.

  According to the present invention, the condensed water generated with the cooling of the EGR gas is collected by the condensed water collecting means and the condensed water colliding with the condensed water collecting means is evaporated while having a simple and inexpensive configuration. Further, by creating an environment in which condensed water is unlikely to be generated, it is possible to provide an EGR device that can effectively suppress corrosion and damage of each part of the internal combustion engine caused by the condensed water. .

1 is a schematic overall configuration diagram schematically showing a configuration example of an internal combustion engine including an EGR device according to Embodiment 1 of the present invention. It is a side view (figure seen from the A arrow direction of FIG. 1) which expands and shows the EGR apparatus which concerns on an Example same as the above. It is a figure (figure seen from the B arrow direction of Drawing 2) showing the example of 1 composition of the condensed water collection board concerning an example same as the above. It is a side view for demonstrating the arrangement | positioning position of the condensed water collection board of the EGR apparatus which concerns on an Example same as the above. It is a schematic whole block diagram which shows roughly the example of 1 structure of the internal combustion engine provided with the EGR apparatus which concerns on Example 2 of this invention. It is a schematic diagram for demonstrating control of the EGR apparatus which concerns on an Example same as the above.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below.

  As shown in FIG. 1, in the internal combustion engine 1 according to Example 1 of the present embodiment, outside air (fresh air) is drawn through an air cleaner or the like (not shown). Then, after being guided to a compressor (impeller) 3A of the supercharger 3 and compressed to a predetermined level, it is cooled to a predetermined level via an intercooler 4 interposed in the intake passage 2 and is put into a combustion chamber (cylinder) 5. Led.

  The gas after combustion discharged from the combustion chamber 5 is led to an exhaust passage (exhaust manifold portion) 7 through an exhaust port (not shown) opened to the combustion chamber 5, and then the supercharger 3. After supplying rotational energy to the exhaust turbine 3B, the exhaust gas is purified by receiving predetermined processing in an exhaust treatment device (not shown) (an oxidation catalyst, a NOx reduction catalyst, a diesel particulate filter, etc.) disposed downstream of the exhaust passage 6. And discharged into the atmosphere.

  Here, in the present embodiment, a part of the gas after combustion (that is, the exhaust gas) is led again to the combustion chamber 5 together with the intake air (fresh air), thereby reducing the combustion temperature and reducing NOx. An EGR device 100 is provided.

  An EGR device (system) 100 according to the present embodiment includes an EGR passage (exhaust gas recirculation passage) 101 that communicates with an exhaust passage (exhaust manifold portion) 6, and the EGR passage 101 includes the EGR passage 101. An EGR cooler 110 is provided for cooling the exhaust gas (EGR gas: recirculation exhaust gas) flowing through the air.

  An EGR valve 120 is interposed in the vicinity of the connection portion between the EGR passage 101 and the intake passage 2, and in a predetermined operation state, a part of the exhaust flowing through the exhaust passage 6 is partially opened by EGR gas. As described above, while being cooled by the EGR cooler 110, it is guided to the intake passage 2 of the internal combustion engine 1.

  The EGR cooler 110 functions as a heat exchanger, and is configured to be able to cool EGR gas flowing in an elongated tubular heat transfer tube in the EGR cooler 110 by a cooling medium such as water or air.

  Here, in order to further promote NOx reduction, when the EGR gas is cooled from about 150 ° C. to 100 ° C. or less, there is a high possibility that condensed water is generated from the cooled EGR gas. In the present embodiment, the generated condensed water can be collected and the condensed water can be evaporated, so that the corrosion or damage of each part of the internal combustion engine caused by the condensed water is more effectively suppressed. did.

  That is, the EGR passage 101 on the downstream side of the EGR cooler 110 is provided with a condensed water collecting plate 300 as an example of condensed water collecting means.

  As shown in an enlarged view in FIG. 2, the condensed water collecting plate 300 is disposed in the EGR passage 101 on the downstream side of the EGR cooler 110 along a direction intersecting with the flow of EGR gas. In addition, although the angle which cross | intersects with respect to the flow of EGR gas of this condensed water collection board 300 is not specifically limited, Although it can also be made into a substantially right angle, in a present Example, as illustrated in FIG. The lower end side of the condensed water collecting plate 300 is inclined and disposed so as to be located on the downstream side of the EGR gas flow with respect to the upper end side.

  A condensed water collection tank 320 serving as condensed water storage means is provided on the downstream side of the EGR gas flow near the lower end of the condensed water collecting plate 300 via a communication passage 321 opened facing the EGR passage 101. ing. The communication passage 321 is preferably branched downward from the EGR passage 101 in the direction of gravity so that the condensed water can be recovered well and the recovered condensed water does not flow backward.

  A drain valve for discharging the collected and collected condensed water can be provided at the bottom of the condensed water collecting tank 320. Further, an adsorbent that adsorbs and holds the condensed water collected and recovered may be provided inside the condensed water recovery tank 320.

  As shown in FIG. 3, the condensate collecting plate 300 preferably has a shape that easily collects condensate in the EGR gas and has a small pressure loss. It is formed in a mesh shape arranged by a technique.

  The size of the mesh (opening gap) is not particularly limited, and can be, for example, about □ 3 mm to □ 15 mm. However, the shape of the gap is not limited to a rectangle, and may be another shape.

  Moreover, since the material of the condensate water collection board 300 needs water resistance, heat resistance, and acid resistance, stainless steel etc. can be employ | adopted.

  The condensed water collecting plate 300 may be formed by punching a plurality of openings in a metal plate (such as punching metal).

Furthermore, a heater power supply 310 is connected to the condensed water collecting plate 300 according to the present embodiment, and power is supplied from the heater power supply 310 by an energization start signal from the ECU (engine control unit) 200 and functions as a heater. The energization from the heater power supply 310 is stopped by the energization stop signal from the ECU 200.
The energization heating function of the condensed water collecting plate 300 by the heater power supply 310 corresponds to a heating unit.

  In the internal combustion engine 1 of the first embodiment having such a configuration, the condensed water generated in the EGR cooler 110 flows in the EGR passage 101 together with the EGR gas and reaches the condensed water collecting plate 300.

  The condensed water (droplet) colliding with the condensed water collecting plate 300 is likely to adhere to the condensed water collecting plate 300 due to the surface tension between the condensed water collecting plate 300 and the droplets. The droplets adhering to the condensate collecting plate 300 grow together with the droplets adhering to the vicinity or with the droplets that flow one after the other to grow.

  Since the droplet grows and becomes heavier, it grows heavier, so that the droplet travels down through the condensed water collecting plate 300 and passes through a communication passage 321 disposed on the lower side of the condensed water collecting plate 300. Then, it is recovered in the condensed water recovery tank 320.

  For this reason, according to the present embodiment, the condensed water can be collected more efficiently than in the case where the condensed water collecting plate 300 is not provided. Therefore, the EGR valve 120, the EGR passage 101, the intake passage 2, Corrosion of the combustion chamber 5 can be suppressed. Further, since the condensed water can be stored in the condensed water recovery tank 320, the combustion chamber of the internal combustion engine can be prevented from sucking a large amount of condensed water, and the internal combustion engine can be prevented from being soaked by a so-called water hammer. Damage and the like can be suppressed.

  Further, in the present embodiment, since the heater function is added to the condensed water collecting plate 300, electric power is supplied from the heater power supply 310 to the condensed water collecting plate 300 to cause the condensed water collecting plate 300 to generate heat. Accordingly, at least a part of the condensed water (droplets) colliding with the condensed water collecting plate 300 can be evaporated.

  Thus, according to the present embodiment, the droplets can be evaporated, so that the amount of condensed water flowing downstream (combustion chamber 5 of the internal combustion engine 1) can be reduced, further contributing to protection of the internal combustion engine. can do. Further, when the droplets evaporate, the droplets take away the surrounding heat, so that the increase in the EGR gas temperature can be suppressed.

  After the EGR passage 101 merges with the intake passage 2, the acid concentration (for example, sulfuric acid concentration) of the gas is lowered by mixing with fresh air, so that the acid dew point (temperature at which sulfuric acid is condensed) is lowered. Condensed water is less likely to be generated. Therefore, in order to effectively suppress the recondensation of the condensed water evaporated by the condensed water collecting plate 300 heated via the heater power supply 310, the condensed water collecting plate 300 is the EGR passage 101, It is preferable to provide in the vicinity of the junction with the intake passage 2. However, the present invention is not limited to this, and depending on the specifications and usage environment of the internal combustion engine 1 and the generation mode of condensed water, the EGR passage 101 on the upstream side of the merging portion and on the downstream side of the EGR cooler 110 may be used. It can be arranged.

  As shown in FIG. 4, the condensed water collection plate 300 is configured so that the condensed water collected by the condensed water collection plate 300 can be reliably collected into the condensed water collection tank 320 via the communication passage 321. It is preferable to dispose the lower end of 300 so as to face the opening of the communication passage 321, that is, the lower end of the condensed water collecting plate 300 and the opening of the communication passage 321 overlap.

  Moreover, the cross-sectional shape of the condensate collecting plate 300 (the shape when viewed from the lateral direction in FIG. 3) is not limited to a flat plate shape that is linear, so that the surface area can be earned. It can also be a wave shape or the like.

  By the way, the condensed water collection board 300 can also be arrange | positioned in multiple steps along the flow direction of EGR gas.

  Thus, according to the present embodiment, since the condensed water is collected by the condensed water collecting means and the condensed water colliding with the condensed water collecting means can be evaporated, a simple and inexpensive structure is provided. However, corrosion, damage, and the like of each part of the internal combustion engine caused by the condensed water generated with the cooling of the EGR gas can be effectively suppressed.

Hereinafter, Example 2 according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 4, the basic configuration of the second embodiment is the same as that of the internal combustion engine 1 according to the first embodiment. However, in the second embodiment, the air flow meter 130 for detecting the intake air flow rate and the intercooler 4 A pressure sensor 140 for detecting a supply air pressure (boost pressure) in the outlet passage, a temperature sensor 150 for detecting a supply air temperature (intake manifold temperature) in the intake passage 2 (intake manifold portion), and an inlet gas of the EGR cooler 110 Detection signals such as an inlet gas temperature sensor 160 for detecting the temperature (EGR gas temperature in the EGR passage 101) and an outlet gas temperature sensor 170 for detecting the outlet gas temperature (EGR gas temperature) of the EGR cooler 110, It is input to the ECU 200.

  In the second embodiment, as shown in FIG. 6, a flow rate control valve 180 is interposed in a refrigerant passage of a cooling medium (for example, cooling water) discharged from the EGR cooler 110.

  The flow control valve 180, the EGR valve 120, and the like are controlled in their opening degrees based on a drive signal from the ECU 200.

In the present embodiment, the following control is performed.
That is, in order to suppress corrosion or damage of the internal combustion engine caused by condensed water generated by cooling the EGR gas by the EGR cooler 110, for example, the outlet gas temperature of the EGR cooler 110 is set higher than the acid dew point. It is assumed that However, if the EGR cooler 110 is set so as to ensure the cooling performance of the EGR cooler 110 when the EGR gas flow rate is high, the EGR gas flow rate is low because the acid dew point is below when the EGR gas flow rate is low. If the EGR cooler 110 is set so as to ensure the cooling performance of the EGR cooler 110 according to the case, this time, when the EGR gas flow rate is large, the required EGR rate cannot be ensured due to insufficient cooling, and sufficient NOx is obtained. A reduction effect cannot be achieved.

  Therefore, in this embodiment, the outlet gas temperature of the EGR cooler 110 is controlled by the ECU 200 controlling the opening degree of the flow rate control valve 180 that controls the refrigerant flow rate of the EGR cooler 110.

The principle of control in this embodiment is shown in FIG.
6A shows the acid dew point temperature (T acid dew point), which can be calculated from the intake air amount of the internal combustion engine 1, the outlet pressure of the EGR cooler 110, the fuel injection amount, and the sulfur concentration in the fuel.

  B in FIG. 6 indicates the EGR gas amount, which can be calculated from the intake air amount of the internal combustion engine 1, the boost pressure, the supply air temperature (intake manifold temperature), and the intake charging efficiency (ηv) of the internal combustion engine 1.

  C in FIG. 6 indicates the inlet gas temperature of the EGR cooler 110 (TEGR cooler inlet). Detected by the inlet gas temperature sensor 160.

  D in FIG. 6 indicates the amount of heat of the inlet gas of the EGR cooler 110 (QEGR inlet), which can be calculated from the amount of EGR gas of B, the inlet gas temperature of C (TEGR cooler inlet), and the specific heat of the EGR gas.

  In FIG. 6, E indicates the amount of heat radiation (Qw) to the EGR cooler cooling medium (cooling water) required for cooling to the acid dew point. The amount of heat of the inlet gas of D (QEGR inlet), the acid dew point temperature of A , C inlet gas temperature (TEGR cooler inlet) and B EGR gas amount.

  In FIG. 6, F indicates the amount (qw) of the EGR cooler cooling medium (cooling water) required for cooling to the acid dew point. The amount of heat radiation (Qw) of E to the cooling medium (cooling water), EGR cooler cooling It can be calculated from the specific heat of the medium (cooling water) and the cooler efficiency (ηcool) of the EGR cooler 110.

  Here, if the cooling medium (cooling water) amount q of the EGR cooler 110 is equal to or less than “qw”, the outlet gas temperature of the EGR cooler 110 becomes higher than the acid dew point of A, and the generation of condensed water containing sulfuric acid is generated. Can be suppressed.

  The acid dew point changes depending on the operating state (rotational speed, load, engine temperature, etc.) of the internal combustion engine 1 and “qw” also changes, but by controlling the amount of cooling water in the EGR cooler 110 using the flow control valve 180, Since q can be variably controlled, it is possible to control “EGR cooler outlet gas temperature> acid dew point” regardless of changes in the operating state of the internal combustion engine 1, and thus condensate containing sulfuric acid. While suppressing generation | occurrence | production effectively and reliably, it becomes possible to maintain the cooling performance of an EGR cooler as desired, and can reduce NOx discharge | emission amount effectively.

In the present embodiment, the following control can be further performed.
That is,
(1) By controlling the heater function of the condensate collecting plate 300 as an example of the condensate collecting means according to the operating conditions of the internal combustion engine, both power saving and condensate countermeasures are achieved or optimized.
When the outlet gas temperature of the EGR cooler 110 falls below the acid dew point, sulfuric acid water is generated. Therefore, when the outlet gas temperature of the EGR cooler 110 is detected by the outlet gas temperature sensor 170 and the outlet gas temperature is equal to or lower than the first predetermined temperature (for example, the acid dew point temperature), the condensed water collecting plate 300 is energized. Activate the heater function to promote evaporation of condensed water. On the other hand, when the outlet gas temperature is higher than the first predetermined temperature, the energization of the condensed water collecting plate 300 is stopped to stop the heater function, thereby saving power.
Thereby, the coexistence or optimization of a power saving and a condensed water countermeasure can be aimed at.
In addition, since the EGR gas is not heated more than necessary, the NOx reduction effect can be satisfactorily exhibited as compared with the case where energization is always performed.

  Here, the acid dew point can be calculated from the intake air amount, the outlet pressure of the EGR cooler 110, the fuel injection amount, and the sulfur concentration in the fuel. For example, it can be obtained by storing a table or the like in the ECU 200 in advance and performing a table look. However, in order to realize more accurate control, an air pressure meter 130 and an outlet pressure sensor of the EGR cooler 110 are arranged. Can be configured.

(2) In a low-temperature environment such as a cold region, by defrosting the moisture (condensed water) frozen in the EGR gas passage including the EGR passage 101, the occurrence of blockage of the EGR gas passage caused by the condensed water is suppressed. At the same time, damage to the internal combustion engine due to the suction of ice into the combustion chamber 5 is suppressed.
That is, in a low temperature environment such as a cold district, it is assumed that the EGR gas passage including the EGR passage 101 is cooled when the vehicle is stopped, and moisture in the passage is frozen. Due to the ice, the EGR gas passage may be blocked, or the combustion chamber of the internal combustion engine may suck in the ice and cause damage to the internal combustion engine.
Therefore, in this embodiment, when the outlet gas temperature of the EGR cooler 110 is detected by the outlet gas temperature sensor 170 and the outlet gas temperature is equal to or lower than a second predetermined temperature (for example, the freezing point temperature), the condensed water collecting plate 300 is used. Is energized to activate the heater function to increase the ambient temperature, and when higher than the second predetermined temperature, the energization is stopped.
Thereby, compared with the case where there is no heater function of the condensed water collection board 300, ice can be thawed at an early stage. Further, ice can be trapped by the condensate collecting plate 300, and further, the ice can be melted directly by the heater function of the condensate collecting plate 300, so that ice is formed on the downstream (combustion chamber 5) side. The risk of flowing can be suppressed, and the risk of causing damage or the like to the internal combustion engine can be more reliably suppressed.

(3) Immediately after starting the internal combustion engine or during low temperature operation of the internal combustion engine such as idling for a long time, the EGR gas is heated by the heater function of the condensate collecting plate 300 to improve the low temperature portion of the combustion. And the generation of CO.
That is, when the internal combustion engine is operated at a low temperature, such as immediately after start-up or when idling for a long time, the EGR gas temperature is also low. Therefore, if EGR is executed, combustion may deteriorate and HC and CO emissions may increase. . On the other hand, if EGR is not performed, NOx will increase.
For this reason, in this embodiment, the outlet gas temperature of the EGR cooler 110 is detected by the outlet gas temperature sensor 170, and if the outlet gas temperature is equal to or lower than a third predetermined temperature (for example, exhaust temperature in idling operation), condensation occurs. The water collecting plate 300 is energized to activate the heater function and raise the EGR gas temperature. As a result, even if EGR is executed during low-temperature operation, an increase in the amount of HC and CO emissions can be suppressed, so that EGR can be executed early or at a high EGR rate from a relatively low exhaust temperature state. Therefore, it is possible to effectively reduce NOx emission even at low temperatures.

  Thus, according to the present embodiment, since the condensed water is collected by the condensed water collecting means and the condensed water colliding with the condensed water collecting means can be evaporated, a simple and inexpensive structure is provided. However, corrosion, damage, and the like of each part of the internal combustion engine caused by the condensed water generated with the cooling of the EGR gas can be effectively suppressed.

  In addition, according to the present embodiment, since the heater function of the condensed water collecting plate 300 is controlled in accordance with the operating conditions of the internal combustion engine, both power saving and condensed water countermeasures can be achieved or optimized. Can do.

  Further, according to the present embodiment, in a low-temperature environment such as a cold region, the heater function of the condensed water collecting plate 300 is controlled to operate accordingly, so that the ice is frozen in the EGR gas passage including the EGR passage 101. Moisture (condensed water) can be thawed to suppress the occurrence of blockage of the EGR gas passage caused by the condensed water, and to prevent damage to the internal combustion engine due to suction of ice into the combustion chamber 5 or the like.

  Further, according to this embodiment, when the temperature of the outlet gas of the EGR cooler 110 is equal to or lower than the third predetermined temperature (for example, the exhaust temperature during idling operation) immediately after startup or during low temperature operation of the internal combustion engine such as idling operation for a long time. Since the EGR gas temperature can be raised by energizing the condensate collecting plate 300 and operating the heater function, even if EGR is executed during low temperature operation, the increase in HC and CO emissions is suppressed. Therefore, EGR can be executed at an early stage or at a high EGR rate from a relatively low exhaust temperature state, and as a result, NOx emissions can be effectively reduced even at low temperatures. .

  In addition, according to the 1st-3rd predetermined temperature, it can also be set as the structure which controls the electricity supply degree to the condensed water collection board 300 so that change is possible.

  By the way, the internal combustion engine according to the present invention is not particularly limited. For example, the present invention is applicable not only to a vehicle mounted on a vehicle but also to a stationary type, and also a diesel engine, a gasoline engine, The present invention is applicable to an internal combustion engine that burns other fuels regardless of the combustion method.

  Further, although the case where sulfur is contained in the fuel has been described, the present invention is not limited to this, and the present invention can be applied even to a fuel from which the sulfur content has been removed. However, it is beneficial in that corrosion and damage to the internal combustion engine due to moisture can be effectively suppressed.

  Since the condensed water collection plate 300 and the heating means described in each of the above-described embodiments are configured to heat the metal wire, when such a configuration is employed, for example, the condensed water collecting plate 300 and the heating unit function as a hot wire type air flow meter. Is also possible.

  The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake passage 5 Combustion chamber 6 Exhaust passage 100 EGR apparatus 101 EGR passage 110 EGR cooler 180 Flow control valve (for cooling medium of EGR cooler)
300 Condensate collection plate (Condensate collection means)
310 Heater power supply (heating means)
320 Condensate recovery tank (condensate storage means)
321 communication passage

Claims (5)

An EGR device that recirculates a part of exhaust gas as EGR gas to a combustion chamber through an EGR passage,
Condensed water collecting means for collecting condensed water from EGR gas flowing in the EGR passage;
A condensed water recovery tank for recovering the condensed water collected by the condensed water collecting means;
Heating means for heating the condensed water collecting means to evaporate the condensed water nearby;
Comprising
The condensed water collecting means is constituted by a condensed water collecting plate which is a metal mesh element having a plurality of openings,
The condensate collecting plate is disposed in the EGR passage on the downstream side of the EGR cooler along the direction intersecting the EGR gas flow, and the lower end side of the condensate collecting plate is arranged with respect to the upper end side. And inclined so as to be located downstream of the EGR gas flow,
An EGR apparatus characterized in that a communication passage to a condensed water recovery tank is provided on the downstream side of the EGR gas flow at the lower end of the condensed water collecting plate . An EGR device that recirculates a part of exhaust gas as EGR gas to a combustion chamber through an EGR passage,
Condensed water collecting means for collecting condensed water from EGR gas flowing in the EGR passage;
A condensed water recovery tank for recovering the condensed water collected by the condensed water collecting means;
Heating means for heating the condensed water collecting means to evaporate the condensed water nearby;
Comprising
The condensed water collecting means is constituted by a condensed water collecting plate which is a metal mesh element having a plurality of openings,
The condensate collecting plate is disposed in the EGR passage on the downstream side of the EGR cooler along the direction intersecting the EGR gas flow, and the lower end side of the condensate collecting plate is arranged with respect to the upper end side. And inclined so as to be located downstream of the EGR gas flow,
An EGR device, wherein a lower end of the condensed water collecting plate is disposed so as to overlap with an opening portion of a communication passage to a condensed water recovery tank . The EGR apparatus according to claim 1, wherein the heating unit is a unit configured to energize and heat the condensed water collecting plate . While EGR gas temperature for heating the condensed water collecting plate by the heating means below a predetermined temperature, not when the EGR gas temperature is higher than the predetermined temperature to perform the heating of the condensed water collecting plate by the heating means The EGR device according to any one of claims 1 to 3, wherein And controlling the cooling medium of the EGR cooler in accordance with the operating condition of the internal combustion engine, any of claims 1 to 4 outlet EGR-gas temperature of the EGR cooler, characterized in that to be higher than the acid dew point temperature The EGR apparatus as described in any one.

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