exhaust gas recirculation system

Abstract

To provide an exhaust gas recirculation device capable of improving efficiency of collecting condensation water.SOLUTION: An exhaust gas recirculation device 1 includes: a recirculation passage 7 for returning exhaust gas E of an internal combustion engine 2 from an exhaust passage 6 of the internal combustion engine 2 to an intake passage 5 of the internal combustion engine 2; and a condensation water collection part 13 collecting condensation water in a portion in which the intake passage 5 and the recirculation passage 7 are merged with each other. In the exhaust gas recirculation device 1 having the recirculation passage 7 for returning the exhaust gas E of the internal combustion engine 2 from the exhaust passage 6 of the internal combustion engine 2 to the intake passage 5 of the internal combustion engine 2, condensation water is collected in the portion in which the condensation water is easily accumulated and the intake passage 5 and the recirculation passage 7 are merged with each other, by the condensation water collection part 13. Thus efficiency of collecting the condensation water can be improved.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an exhaust gas recirculation system. [Background technology]

[0002] Exhaust gas recirculation systems have been proposed that return exhaust gas from an internal combustion engine to its intake path. In exhaust gas recirculation systems, moisture contained in the exhaust gas reaches its dew point when the exhaust gas is cooled. The water generated during this process is called condensed water, which can flow into and accumulate in the intake path, causing corrosion of components in the intake path. For example, Patent Document 1 discloses an exhaust gas recirculation system that collects condensed water in a tank installed in an intercooler, neutralizes the collected water in the tank, and injects the neutralized water into the heat exchanger, thereby improving the heat exchange efficiency of the heat exchanger. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-189022 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described technology, since the condensed water is collected by the intercooler, the condensed water that is not collected may accumulate in the intake passage, possibly causing corrosion of the components of the intake passage.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an exhaust gas recirculation system that can improve the efficiency of collecting condensed water. [Means for solving the problem]

[0006] The present invention is an exhaust gas recirculation device that includes a recirculation path that returns exhaust gas from an internal combustion engine from the exhaust path of the internal combustion engine to the intake path of the internal combustion engine, and a condensed water collection section that collects condensed water at the point where the intake path and the recirculation path join.

[0007] According to this configuration, in an exhaust gas recirculation device equipped with a recirculation path that returns the exhaust gas of an internal combustion engine from the exhaust path of the internal combustion engine to the intake path of the internal combustion engine, the condensed water collection section collects condensed water at the point where the intake path and the recirculation path, where condensed water is likely to accumulate, converge, thereby improving the efficiency of collecting condensed water.

[0008] In this case, it is preferable to further include a condensed water supply unit that supplies the condensed water collected by the condensed water collection unit to a heat exchanger of the internal combustion engine.

[0009] According to this configuration, the condensed water collected by the condensed water collection unit is supplied to the heat exchanger of the internal combustion engine by the condensed water supply unit, thereby improving the heat exchange efficiency of the heat exchanger and enabling effective use of the condensed water.

[0010] In addition, the internal combustion engine is mounted on a vehicle that uses the internal combustion engine and an electric motor as its power source for driving, and further comprises a storage tank for storing condensed water collected by the condensed water collection unit, and a condensed water valve for controlling the drainage of condensed water stored in the storage tank, and it is preferable that the condensed water valve drains condensed water stored in the storage tank when the vehicle is running using the electric motor as its power source.

[0011] According to this configuration, the internal combustion engine is mounted on an automobile that uses the internal combustion engine and an electric motor as its power sources for traveling, and in the exhaust gas recirculation system that further includes a storage tank for storing condensed water collected by the condensate collection unit and a condensate valve for controlling the drainage of condensed water stored in the storage tank, the condensate valve drains condensed water stored in the storage tank when the automobile is traveling using the electric motor as its power source and the internal combustion engine is not operating, so that condensed water can be drained from the storage tank without affecting the performance of the internal combustion engine due to the reduced pressure in the intake air that accompanies draining condensed water when the internal combustion engine is operating. [Effects of the Invention]

[0012] According to the exhaust gas recirculation system of the present invention, the efficiency of collecting condensed water can be improved. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing an exhaust gas recirculation device according to an embodiment; [Figure 2] FIG. 2 is a diagram showing details of the condensed water collecting section of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] An exhaust gas recirculation device according to an embodiment of the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1, an exhaust gas recirculation (EGR) device 1 of this embodiment includes an internal combustion engine 2. The internal combustion engine 2 is mounted on an automobile 100 that uses the internal combustion engine 2 and an electric motor 3 as a power source for traveling. Output shafts of the internal combustion engine 2 and the electric motor 3 are connected to a transmission 4. The exhaust gas recirculation device 1 includes an intake path 5 that introduces intake air into the internal combustion engine 2, and an exhaust path 6 that discharges exhaust from the internal combustion engine 2. The exhaust gas recirculation device 1 also includes a recirculation path 7 that returns exhaust gas from the internal combustion engine 2 from the exhaust path 6 of the internal combustion engine 2 to the intake path 5 of the internal combustion engine 2.

[0015] The intake air path 5 introduces intake air via an air cleaner 8. The exhaust gas recirculation system 1 is equipped with a turbocharger 9 having a compressor 10 and a turbine 11. The intake air introduced via the air cleaner 8 is compressed by the compressor 10. The intake air compressed by the compressor 10 is cooled by an air-cooled heat exchanger 12, which is an intercooler. The intake air cooled by the heat exchanger 12 is supplied to the internal combustion engine 2. The exhaust gas recirculation system 1 is equipped with a condensed water collector 13 that collects condensed water at the location where the intake air path 5, which introduces the intake air cooled by the heat exchanger 12 into the internal combustion engine 2, and the recirculation path 7 join together. The condensed water collector 13 will be described in detail later.

[0016] The exhaust path 6 supplies exhaust gas from the internal combustion engine 2 to a turbine 11 of a turbocharger 9. The exhaust gas is led out through a recirculation path 7 branching off from the exhaust path 6 and is cooled by a heat exchanger 14, which is an EGR cooler. The exhaust gas cooled by the heat exchanger 14 is introduced into a condensed water collector 13 via an EGR valve 15.

[0017] 2, the area where the intake air passage 5 that introduces intake air I and the recirculation passage 7 that introduces exhaust air E join has a venturi structure including a constricted portion 27 where the inner diameter of the intake air passage 5 decreases. At the constricted portion 27, the recirculation passage 7 introduces exhaust air E into the intake air I flowing through the intake air passage 5. The condensed water collecting section 13 has a condensed water receiving portion 28 below the constricted portion 27 that receives condensed water generated at the constricted portion 27 and collects the condensed water.

[0018] 1 and 2, the exhaust gas recirculation system 1 includes a storage tank 16 that stores condensed water collected in the condensed water receiving portion 28 of the condensed water collection unit 13. The storage tank 16 is in direct communication with the condensed water receiving portion 28. The exhaust gas recirculation system 1 is also provided with a condensed water valve 17 that controls drainage of the condensed water stored in the storage tank 16 into the intake air I. Because the storage tank 16 is in direct communication with the condensed water receiving portion 28 that is in communication with the intake path 5, when the condensed water valve 17 is opened and the condensed water stored in the storage tank 16 is drained while the internal combustion engine 2 is operating, this is accompanied by a reduction in the pressure of the intake air I in the intake path 5.

[0019] The condensed water drained from the storage tank 16 via the condensed water valve 17 is neutralized by the ion exchange resin filter 18. The condensed water neutralized by the ion exchange resin filter 18 is stored in the storage tank 19. The exhaust gas recirculation system 1 includes a condensed water supply unit 21 that supplies the condensed water collected by the condensed water collection unit 13 to the heat exchanger 12 of the internal combustion engine 2. In this embodiment, the condensed water supply unit 21 supplies the condensed water to the air-cooled heat exchanger 12, which is an intercooler. The condensed water supply unit 21 is supplied with the condensed water stored in the storage tank 19 by a pump 20. The condensed water supply unit 21 is a nozzle that sprays condensed water onto the outer surface of a member that defines a path through which the intake air I of the heat exchanger 12 flows.

[0020] Furthermore, even when the internal combustion engine 2 is operating, the pump 20 is operating, and condensed water is being supplied to the heat exchanger 12 by the condensed water supply unit 21, if the condensed water valve 17 is closed, the pressure of the intake air I in the intake path 5 is not reduced.

[0021] As shown in FIG. 1 , the exhaust gas recirculation system 1 includes an ECU (Electronic Control Unit) 22. The ECU 22 is an electronic computer that controls the operation of the exhaust gas recirculation system 1. The exhaust gas recirculation system 1 includes a temperature sensor 23 that measures the temperature of intake air I, located in the intake air path 5 between the air cleaner 8 and the compressor 10 of the turbocharger 9. The exhaust gas recirculation system 1 includes a temperature sensor 24 that measures the temperature of intake air I, located in the intake air path 5 between the heat exchanger 12, which is an intercooler, and the condensed water collection unit 13. Signals indicating the measured values ​​from the temperature sensors 23 and 24 are transmitted to the ECU 22. The ECU 22 also receives a signal indicating the operating state of the internal combustion engine 2.

[0022] The ECU 22 sends command signals to the EGR valve 15 and the condensed water valve 17 while referring to the measured values ​​of the temperature sensors 23, 24 and the operating state of the internal combustion engine 2, thereby controlling the operations of the EGR valve 15 and the condensed water valve 17. In response to the command signal from the ECU 22, the condensed water valve 17 drains the condensed water stored in the storage tank 16 when the automobile 100 is running using the electric motor 3 as a power source and the internal combustion engine 2 is not operating. The condensed water drained from the storage tank 16 is neutralized by the ion exchange resin filter 18 and stored in the storage tank 19.

[0023] On the other hand, when the automobile 100 is running using the internal combustion engine 2 as a power source and the internal combustion engine 2 is operating, the condensed water valve 17 closes the condensed water valve 17 in response to a command signal from the ECU 22 so as to prevent the pressure of the intake air I from being reduced. When the automobile 100 is running using the internal combustion engine 2 as a power source, the pump 20 operates in response to a command signal from the ECU 22, and the condensed water stored in the storage tank 19 is supplied to the heat exchanger 12 by the condensed water supply unit 21.

[0024] When the automobile 100 is running using the electric motor 3 as a power source, the electric motor 3 is supplied with power from the battery 26 via the inverter 25. Furthermore, during regeneration, the electric motor 3 supplies power to the battery 26 via the inverter 25 to charge the battery 26.

[0025] According to this embodiment, in an exhaust gas recirculation system 1 including a recirculation path 7 that returns exhaust gas E from the internal combustion engine 2 from the exhaust path 6 of the internal combustion engine 2 to the intake path 5 of the internal combustion engine 2, the condensed water collection unit 13 collects condensed water at the location where the intake path 5 and the recirculation path 7, where condensed water is likely to accumulate, join, thereby improving the efficiency of collecting condensed water. In other words, in this embodiment, by arranging the condensed water collection unit 13 at the location where the intake path 5 and the recirculation path 7, where condensed water is likely to accumulate, it is possible to collect condensed water that could not be collected by an intercooler in the technology such as that of Patent Document 1.

[0026] Incidentally, the area where the intake path 5 and the recirculation path 7 join may be equipped with a Venturi structure as in this embodiment to efficiently introduce exhaust gas E into the intake air I, but this structure makes it easy for condensed water to accumulate, making it susceptible to corrosion due to the condensed water. If the structure of the area where the intake path 5 and the recirculation path 7 join is changed to prevent condensed water from accumulating, the Venturi effect cannot be expected. On the other hand, in this embodiment, condensed water is collected in the condensed water receiving portion 28 below the narrowed portion 27 of the Venturi structure in the intake path 5 where condensed water tends to accumulate. Therefore, the condensed water can be efficiently collected while the Venturi effect allows the exhaust gas E to be efficiently introduced into the intake air I.

[0027] Furthermore, according to this embodiment, the condensed water supply unit 21 supplies the condensed water collected by the condensed water collection unit 13 to the heat exchanger 12 of the internal combustion engine 2, thereby improving the heat exchange efficiency of the heat exchanger 12 and enabling effective use of the condensed water.

[0028] Furthermore, in the technology described in Patent Document 1, when the amount of condensed water collected in the storage tank reaches a certain level, such as when the tank is full, a condensed water valve opens to direct the condensed water to a device that neutralizes the condensed water. However, if the internal combustion engine is operating at that time, the intake air I is decompressed, which affects the performance of the internal combustion engine.

[0029] On the other hand, according to this embodiment, the internal combustion engine 2 is mounted on an automobile 100 that uses the internal combustion engine 2 and an electric motor 3 as its power source for running, and in the exhaust gas recirculation device 1 that further includes a storage tank 16 that stores condensed water collected by the condensed water collection unit 13 and a condensed water valve 17 that controls the drainage of condensed water stored in the storage tank 16, the condensed water valve 17 drains condensed water stored in the storage tank 16 when the automobile 100 is running using the electric motor 3 as its power source and the internal combustion engine 2 is not operating, so that condensed water can be drained from the storage tank 16 without affecting the performance of the internal combustion engine 2 due to the reduced pressure in the intake air that accompanies draining condensed water when the internal combustion engine 2 is operating.

[0030] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be embodied in various forms. For example, the storage tank 16 may be omitted. In this case, the condensed water receiver 28 functions as the storage tank 16. Furthermore, in the above embodiment, a high-pressure exhaust gas recirculation system is disclosed in which the exhaust gas E is diverted directly from the exhaust path 6 of the internal combustion engine 2 to the recirculation path 7. However, the exhaust gas recirculation system 1 of this embodiment can also be applied to a low-pressure exhaust gas recirculation system in which the exhaust gas E that has passed through the turbine 11 of the turbocharger 9 is introduced into the intake path 5 upstream of the compressor 10 of the turbocharger 9 via a recirculation path that is arranged separately from the recirculation path 7 shown in FIG. 1 .

[0031] Furthermore, turbocharger 9 may be omitted. Furthermore, the heat exchanger to which condensed water supply unit 21 supplies condensed water is not limited to heat exchanger 12, which is an intercooler, but may also be, for example, heat exchanger 14, which is an EGR cooler. Furthermore, if reuse of condensed water is not taken into consideration, condensed water supply unit 21 may be omitted. Furthermore, if the impact on the performance of internal combustion engine 2 is not taken into consideration, internal combustion engine 2 may be mounted on automobile 100 using internal combustion engine 2 as its only power source for traveling, and condensed water stored in storage tank 16 may be drained while internal combustion engine 2 is operating. [Explanation of symbols]

[0032] 1...exhaust gas recirculation device, 2...internal combustion engine, 3...electric motor, 4...transmission, 5...intake path, 6...exhaust path, 7...recirculation path, 8...air cleaner, 9...turbocharger, 10...compressor, 11...turbine, 12...heat exchanger, 13...condensate collection section, 14...heat exchanger, 15...EGR valve, 16...storage tank, 17...condensate valve, 18...ion exchange resin filter, 19...storage tank, 20...pump, 21...condensate supply section, 22...ECU, 23, 24...temperature sensor, 25...inverter, 26...battery, 27...throttle section, 28...condensate receiving section, 100...automobile, I...intake, E...exhaust.

Claims

1. a recirculation path for returning the exhaust gas of the internal combustion engine from the exhaust path of the internal combustion engine to the intake path of the internal combustion engine; a condensed water collecting section that collects condensed water at a location where the intake path and the recirculation path join; Equipped with the portion where the intake path and the recirculation path join has a venturi structure including a narrowed portion where an inner diameter of the intake path decreases, The condensed water collecting portion is provided below the constricted portion and has a condensed water receiving portion that collects the condensed water. Exhaust gas recirculation system.

2. A recirculation path that returns exhaust gas from the internal combustion engine from an exhaust path of the internal combustion engine to an intake path of the internal combustion engine; a condensed water collecting section that collects condensed water at a location where the intake path and the recirculation path join; an intercooler provided in the intake path of the internal combustion engine; a condensed water supply unit that supplies the condensed water collected by the condensed water collection unit to the intercooler, The portion where the intake path and the recirculation path join is the intake path on the internal combustion engine side relative to the intercooler. Exhaust gas recirculation system.

3. the internal combustion engine is mounted on an automobile that uses the internal combustion engine and an electric motor as a power source for running, a storage tank that stores the condensed water collected by the condensed water collection unit; a condensed water valve for controlling drainage of the condensed water stored in the storage tank; Furthermore, 3. The exhaust gas recirculation system according to claim 1, wherein the condensed water valve drains the condensed water stored in the storage tank when the vehicle is running using the electric motor as a power source.

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