JP2013256918A - Cleaning method of egr valve of internal combustion engine and internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method of an EGR valve of an internal combustion which can remove soot attached to the EGR valve by utilizing compressed air stored in advance for assisting supercharging when operation of the internal combustion engine is finished, the internal combustion engine having a turbo supercharging system, a supercharging assist system which introduces the compressed air stored in advance into a cylinder and an EGR system, and to provide the internal combustion engine.SOLUTION: In a cleaning method of an EGR valve of an internal combustion engine provided with a turbo supercharging system 1, a supercharging assist system 10 which supplies compressed air Ac stored in a compressed air tank 22 in advance into a cylinder by switching from an air inlet passage 12a to a supercharging assist passage 23 by a flow passage switching device 24, and an EGR system having the EGR valve 20, when operation of the internal combustion engine is finished, the EGR valve 20 is cleaned by supplying the compressed air Ac stored in the compressed air tank 22 to a cleaning device 40 provided to the EGR valve 20.

Description

  The present invention has a turbo-type supercharging system, a supercharging assist system that introduces compressed air stored in advance in a cylinder in order to compensate for an air amount shortage caused by a turbo lag generated during transient operation of an internal combustion engine, and an EGR valve. The present invention relates to a method for cleaning an EGR valve of an internal combustion engine provided with an EGR system, and the internal combustion engine.

  A turbo-type supercharging system 1 as shown in FIG. 11 is used for an internal combustion engine (engine) mounted on a vehicle such as an automobile. This turbo-type supercharging system 1 is an intake manifold of an engine body 11. It has an intake passage 12 connected to 11a and an exhaust passage 13 connected to an exhaust manifold 11b. Further, an air cleaner 14, a compressor 15 a of a turbocharger (turbocharger) 15, an intercooler 16 and a throttle valve 17 are disposed in the intake passage 12 from the upstream side, and a turbo type is provided in the exhaust passage 13. A turbine 15b of the supercharger 15 is provided. Further, the upstream side of the turbine 15 b in the exhaust passage 13 and the downstream side of the throttle valve 17 in the intake passage 12 are connected by an EGR passage 18, and an EGR cooler 19 and an EGR valve 20 are provided in the EGR passage 18.

  The turbocharger 15 is provided with two impellers at both ends of one shaft (shaft), and rotates the impeller by flowing exhaust gas G to one of them (the turbine 15b side), thereby rotating the impeller. The air A taken in by the other impeller (compressor 15a side) is compressed. In other words, the compressor 15a uses the work extracted from the exhaust gas G by using the turbine 15b to compress the air A. Thereby, since the air A of a high pressure compared with the past can be introduce | transduced in a cylinder, the air quantity introduce | transduced in a cylinder can be increased. Therefore, in the turbocharger system 1 using the turbocharger 15, since more air A can be introduced into the cylinder, it is possible to improve torque and reduce exhaust gas harmful substances.

  However, the turbocharging by the turbocharging system 1 has a disadvantage in that a so-called turbo lag is generated due to a time difference before the turbocharger 15 can be introduced into the cylinder with the required amount of air. There is. The turbo lag rotates the turbine 15b using the pressure of the exhaust gas G, and the compressor 15b is operated by the rotation to compress the air A. The air A is sent into the cylinder (inside the cylinder) and burned. This is a phenomenon that must occur in the turbocharging system 1 that repeats the cycle of further rotating the turbine 15b with the exhaust gas G to increase the amount of air A introduced into the cylinder, and particularly occurs during transient operation.

  At the time of transient operation, as shown in FIG. 12, as the engine rotational speed increases, the required air amount b also increases. However, when this turbo lag occurs, the required air amount b cannot be secured. At this time, the required air amount b increases with respect to the required fuel amount (fuel injection amount) B according to the changing engine speed and load (accelerator opening). The amount of air c supplied to is reduced only by the shaded area. As a result, when the amount of air c is small, the combustible fuel amount C decreases and the output of the internal combustion engine decreases, and when EGR cannot be applied, NOx increases and exhaust performance deteriorates. That is, in the supercharging system 1 shown in FIG. 11, since the turbo lag is generated during the transient operation, the necessary air amount A cannot be ensured, and the exhaust performance deteriorates.

  Therefore, as a countermeasure against the deterioration of output and exhaust performance due to the turbo lag, as shown in FIG. 13, a method of compensating for the shortage of the air amount A during transient operation by introducing pre-accumulated compressed air Ac onto the intake passage 12 as shown in FIG. When the engine speed and load (accelerator opening) change rapidly, simultaneously with this change, the compressed air Ac previously stored in the compressed air tank 22 using the supercharger or the air compressor 21 or the like flows. There is a supercharging assist system 10 that switches from the air suction passage 12a to the supercharging assist passage 23 by a path switching device (switching valve) 24 and introduces it into the intake passage 12 to compensate for the shortage of air amount during transient operation.

  When the supercharging assist system 10 is employed, the compressed air Ac flows back to the air intake passage 12a upstream of the intake passage 12, that is, the air cleaner 14 side during supercharging assistance. In order to prevent this, it is necessary to install a backflow prevention valve (backflow prevention valve) in the intake passage 12 (or 12a). However, in the configuration of FIG. Along with the function of controlling the end, the function of preventing the backflow of the compressed air Ac is provided.

  As another example of the supercharging assist system, for example, a supercharged air passage connected to an intake passage and a supercharged air that stores supercharged air of a predetermined pressure and sends the supercharged air to the supercharged air passage. Backflow prevention provided in the tank, a supercharging valve provided in the supercharging air passage, which opens and closes according to the engine operating state, and an intake air passage upstream of the portion where the supercharging air passage is connected to prevent backflow of the intake air There has been proposed a supercharging device for an internal combustion engine including a valve (see, for example, Patent Document 1).

  With this supercharging assistance, the entropy recovered by the turbine side of the supercharger is increased compared with the case where supercharging assistance is not performed, so that the responsiveness of the supercharger is improved, thereby improving the turbo lag and starting. It is possible to improve performance and reduce harmful components of exhaust gas.

  When the supercharging assist system using this compressed air tank is adopted, when the operation of the internal combustion engine is finished, it is condensed if left as it is, and when it is used next, moisture enters the engine. Since it becomes a cause of failure, it is necessary to discharge the compressed air accumulated in the compressed air tank to the atmosphere.

  On the other hand, in the operation of the internal combustion engine, when supercharging assistance is not performed, normal operation is performed. In this normal operation, intake air and EGR gas are mixed using an EGR (exhaust gas recirculation) system. By introducing the gas into the cylinder (inside the cylinder), the fuel temperature in the cylinder is lowered, and NOx is reduced. If this EGR gas is introduced more than necessary, the amount of smoke (SM) emission increases, so the ratio of intake air and EGR gas must be set to an appropriate ratio in accordance with the operating conditions of the internal combustion engine. This appropriate ratio is set in advance by experiments or the like, but in order to achieve EGR at this appropriate ratio, the amount of EGR gas introduced into the cylinder is controlled using an EGR valve disposed in the EGR passage. ing.

  This EGR valve includes a pressure type EGR valve (for example, see Patent Document 2) and an EGR valve (for example, see Patent Document 3) driven by a motor. In this motor-driven EGR valve, a return spring is used. The valve is opened and closed by a balance between the force for energizing the valve and the force for pushing the valve in the opening direction by the shaft driven by the motor.

  However, since the EGR gas is an exhaust gas itself, and there is a smoke component in the exhaust gas, the smoke component adheres to the EGR valve, hinders the control of the EGR valve, and the EGR valve has a minute amount. There is a problem that the opening degree cannot be controlled and the exhaust gas state deteriorates or the engine output deteriorates.

  In order to avoid the sticking of the EGR valve, when it is determined that there is a possibility that the EGR valve is stuck and closed, and the determination means for the possibility of the high pressure EGR valve provided in the high pressure EGR passage, There has been proposed an exhaust gas recirculation device for an internal combustion engine provided with a sticking avoidance means for forcibly opening and closing an EGR valve between a fully closed state and an intermediate opening degree one or more times continuously for a predetermined time (for example, a patent) Reference 4).

  Since the sticking avoidance operation by the sticking avoidance means is performed during the EGR operation, the EGR passage using both the high pressure EGR and the low pressure EGR is provided with two systems, and when one EGR valve is performing the sticking avoidance operation. Therefore, it is necessary to correct the opening degree of the other EGR valve so as to cancel the change caused by the sticking avoidance operation.

JP 2011-208644 A Japanese Patent Laid-Open No. 11-200958 JP 2007-198243 A JP 2008-8207 A

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a turbocharger system, an internal combustion engine including an EGR system and a supercharge assist system that introduces prestored compressed air into the cylinder. Provided is a method for cleaning an EGR valve of an internal combustion engine and an internal combustion engine capable of removing soot adhering to the EGR valve using compressed air stored in advance for supercharging assistance when the operation of the internal combustion engine is completed There is to do.

  In order to achieve the above object, a method for cleaning an EGR valve of an internal combustion engine according to the present invention includes a turbo-charging system and a compressed air tank that is switched in advance from an air suction passage to a supercharging auxiliary passage by means of a passage switching device. In a method for cleaning an EGR valve of an internal combustion engine provided with a supercharging assist system for supplying compressed air stored in the cylinder into the cylinder and an EGR system having an EGR valve, the compression is performed when the operation of the internal combustion engine is terminated. In this method, the compressed air stored in the air tank is supplied to a cleaning device provided in the EGR valve to clean the EGR valve.

  According to this method, when the operation of the internal combustion engine is stopped and the compressed air used in the supercharging assist system is discharged, the EGR valve can be cleaned using the compressed air, and the attached EGR valve Since the valve body can be prevented from sticking to the valve seat, the controllability such as the fine opening degree control of the EGR valve can be kept good.

  Further, in the above EGR valve cleaning method, the valve body of the EGR valve in a closed state is rotated around the drive shaft by the compressed air stored in the compressed air tank so that the valve body and the valve seat are moved. If the EGR valve is cleaned by sliding, the EGR valve can be cleaned relatively easily.

  The internal combustion engine of the present invention for achieving the above object is stored in the compressed air tank in advance by switching from the air intake passage to the supercharging auxiliary passage by the turbo-type supercharging system and the flow path switching device. An internal combustion engine having a supercharging assist system for supplying compressed air into a cylinder and an EGR system having an EGR valve is provided with an air pipe for connecting the compressed air tank and a cleaning device for the EGR valve. Provided with a control valve for controlling the supply of compressed air to the cleaning device, and when the operation of the internal combustion engine is finished, the control valve is controlled so that all of the compressed air discharged from the compressed air tank is discharged. Alternatively, a control device configured to supply a part to the cleaning device and perform control to clean the EGR valve is provided.

  According to this configuration, when the operation of the internal combustion engine is stopped and the compressed air used in the supercharging assist system is discharged, the EGR valve can be cleaned using the compressed air, and the attached EGR valve Since the valve body can be prevented from sticking to the valve seat, the controllability such as the fine opening degree control of the EGR valve can be kept good.

  In the internal combustion engine, the cleaning device receives supply of compressed air, rotates the valve body of the EGR valve in a closed state around the drive shaft, and slides the valve body and the valve seat together. If the EGR valve is configured to be cleaned, the EGR valve can be cleaned relatively easily.

  According to the cleaning method and the internal combustion engine of the EGR valve of the internal combustion engine according to the present invention, in the internal combustion engine provided with the turbo-type supercharging system, the supercharging assist system for introducing the prestored compressed air into the cylinder, and the EGR system, When the operation of the internal combustion engine is finished and the compressed air for supercharging assistance previously stored in the compressed air tank is released, the soot adhering to the EGR valve can be removed using the released compressed air. .

  As a result, the EGR valve can be cleaned, and the valve body of the EGR valve can be prevented from sticking to the valve seat with the adhering stick, so that controllability such as the fine opening degree control of the EGR valve can be kept good.

It is a figure showing typically composition of an internal-combustion engine of an embodiment of the invention. It is a figure which shows the structure of the EGR valve used with the internal combustion engine of embodiment of this invention, and its cleaning apparatus, and is a figure when an EGR valve is a valve closing state. It is a figure which shows the structure of the EGR valve of FIG. 2, and its cleaning apparatus, and is a figure when an EGR valve is a valve opening state. It is a partial perspective view which shows the structure of the cleaning apparatus of FIG. It is a figure which shows a motion of the cleaning apparatus, and is a figure which shows the state before supply of compressed air. It is a figure which shows a motion of the cleaning apparatus, and is a figure which shows the state immediately after the supply start of compressed air. It is a figure which shows a motion of the cleaning apparatus, and is a figure which shows the state during supply of compressed air. It is a figure which shows the motion of the cleaning apparatus, and is a figure which shows the state in the middle of escape of compressed air. It is a figure which shows the motion of a cleaning apparatus, and is a figure which shows the state which escaped compressed air. It is a figure which shows another example of a cleaning apparatus. It is a figure which shows typically the structure of the internal combustion engine provided with the single stage supercharging system. It is a figure which shows the fuel injection quantity and air quantity with respect to the engine speed of an internal combustion engine provided with the supercharging system. It is a figure which shows typically the structure of the internal combustion engine provided with the single stage supercharging system, the supercharging assistance system, and the EGR system.

  Hereinafter, an EGR valve cleaning method and an internal combustion engine of an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, an internal combustion engine (engine) according to an embodiment of the present invention has an intake passage 12 connected to an intake manifold 11a of an engine body 11, and an exhaust passage 13 connected to an exhaust manifold 11b. Furthermore, the turbo-type supercharging system 1, the supercharging assistance system 10, and the EGR systems 18 to 20 are provided.

  An air cleaner 14 is installed in the air intake passage 12a on the upstream side of the intake passage 12, and a compressor of a turbo-type supercharger (turbocharger) 15 is provided in order from the upstream side to the intake passage 12 on the downstream side of the air intake passage 12a. 15a, an intercooler 16 and a throttle valve 17 are provided, and a turbine 15b of a turbocharger 15 is provided in the exhaust passage 13. A turbocharger system 1 is configured by the compressor 15a and the turbine 15b of the turbocharger 15.

  In addition, a compressor 21 that generates compressed air Ac and a compressed air tank 22 that stores the compressed air Ac are provided to supply the compressed air Ac to the intake passage 12 in response to a shortage of air due to the turbo lag during transient operation. The supercharging assistance passage 23 is connected via a flow path switching device (switching valve) 24 disposed at the boundary between the air suction passage 12 a and the intake passage 12. The supercharging assistance system 10 is comprised by these.

  By this flow switching device 24, during the transient operation of the internal combustion engine, the intake supply passage is switched from the air intake passage 12 a to the supercharging auxiliary passage 23, and the compressed air Ac is supplied from the supercharging auxiliary passage 23 to the intake passage 12. Provide supercharging assistance. As the flow path switching device 24, since it is necessary to switch the flow path in an extremely short time on the order of msec, it is preferable to use a shutter type switching valve as shown in FIG. The compressed air tank 22 is provided with a pressure sensor (not shown) for measuring the internal pressure. The air intake passage 12a is provided with an intake air amount sensor (MAF sensor: not shown) for measuring the flow rate of the air A.

  Further, the upstream side of the turbine 15 b in the exhaust passage 13 and the downstream side of the throttle valve 17 in the intake passage 12 are connected by an EGR passage 18, and an EGR cooler 19 and an EGR valve 20 are provided in the EGR passage 18. Thus, the EGR systems 18 to 20 are configured.

  As shown in FIGS. 2 and 3, the EGR valve 20 supports a drive shaft 20c having a valve main body 20b fixed to a case 20a so as to be movable, and the valve main body 20b and the valve seat 20d are separated from and contact each other. It is configured as follows. One end side (arrow A side) of this drive shaft 20c is pivotally supported by the end 20k of the case 20a, and the other end side (arrow B side) is fixed to a first spring fixing plate 20e that can move in the case 20a. ing.

  Between the first spring fixing plate 20e and the second spring fixing plate 20g that is penetrated by the drive shaft 20c and is fixed to the case 20a on the valve body 20b side (arrow A side) with respect to the biasing spring 20f. Further, an urging spring 20f that urges the valve body 20b in the valve closing direction (arrow B side) is disposed. Further, the first spring fixing plate 20e is opposed to the urging force of the urging spring 20f, and the piston 20j and the piston shaft 20i moving the valve body 20b in the valve opening direction (arrow A side), and the piston shaft 20i is expanded and contracted. An electric motor 20h is provided.

  Further, the upstream side of the EGR passage 18 is connected to the valve opening direction side (arrow A side) of the valve body 20b from the position of the valve seat 20d, and the downstream side of the EGR passage 18 is connected to the valve seat 20d from the position of the valve seat 20d. The main body 20b is connected to the valve closing direction side (arrow B side), that is, between the valve seat 20d and the second spring fixing plate 20g.

  With this configuration, as shown in FIG. 2, when the piston shaft 20i is contracted by the operation of the electric motor 20h and the piston 20j is moved to the electric motor 20h side (arrow B side), the urging force of the urging spring 20f The first spring fixing plate 20e and the drive shaft 20c move to the electric motor 20h side (arrow B side), and the valve body 20b contacts the valve seat 20d to stop the flow of EGR gas Ge.

  On the other hand, as shown in FIG. 3, when the piston shaft 20i is extended by the operation of the electric motor 20h and the piston 20j is moved to the valve body 20b side (arrow A side), the biasing force of the biasing spring 20f is resisted. Thus, the first spring fixing plate 20e and the drive shaft 20c move to the valve body 20b side (arrow A side), and the valve body 20b moves away from the valve seat 20d so that the EGR gas Ge flows. Further, by controlling the expansion / contraction amount of the piston shaft 20i of the electric motor 20h, the separation distance between the valve body 20b and the valve seat 20d can be controlled, and the flow rate of the EGR gas Ge can be controlled.

  In the present invention, as shown in FIG. 1, when the operation of the internal combustion engine is finished, the compressed air Ac of the compressed air tank 22 of the supercharging assist system 10 is used to clean the EGR valve 20, An air pipe 25 that connects the compressed air tank 22 and the cleaning device 40 of the EGR valve 20 is provided, and a first control valve 26 and a second control valve that control the supply of compressed air Ac to the cleaning device 40 in the air pipe 25. 27 is provided.

  As shown in FIGS. 2 to 4, the cleaning device 40 includes a piston 41 disposed in the vicinity of the end 20k in the opposite direction (arrow A side) to the direction in which the electric motor 20h of the case 20a is present, A moving member 42 that expands and contracts by the piston 41, a movable protrusion 43 fixed to the moving member 42, and an engagement blade fixed to the drive shaft 20c protruding from the end 20k of the case 20a and engaging with the movable protrusion 43 44. Note that a key 42a is provided on the upper portion of the moving member 42 so as not to move left and right, and is inserted into the key groove 41e on the piston 41 side.

  As shown in FIGS. 5 to 9, the piston 41 includes a spring chamber 41a, an air chamber 41b, a piston wall 41c provided therebetween, and the piston wall 41c disposed in the spring chamber 41a in the direction of arrow D. And a spring body 41d for biasing. In addition, an air pipe 25 having a first control valve 26 and an air pipe 25 having a second control valve 27 are connected to the air chamber 41b. The air pipe 25 is connected to the compressed air tank 22 as shown in FIG. 1, and when the first control valve 26 is opened and the second control valve 27 is closed, the compressed air Ac is supplied to the cleaning device 40. When the first control valve 26 and the second control valve 27 are opened, the compressed air Ac is released into the atmosphere.

  Next, a method for cleaning the EGR valve 20 of the internal combustion engine will be described. In this cleaning method, a control device (not shown) for controlling the first control valve 26 and the second control valve 27 is an engine control device (not shown) called an ECU (engine control unit) for controlling the whole internal combustion engine. ) Or a part of this engine control device.

  Further, when the operation of the internal combustion engine is terminated, the control device controls the opening and closing of the first control valve 26 and the second control valve 27 shown in FIG. 1 as shown in FIGS. Control is performed to supply all or part of the compressed air Ac discharged from the tank 22 to the cleaning device 40 to clean the EGR valve 20.

  As shown in FIG. 5, during the operation of the internal combustion engine, the first control valve 26 is closed, and the second control valve 27 is closed or opened. In this state, since compressed air Ac is not supplied to the air chamber 41b, the piston wall 41c is moved in the arrow D direction by the spring body 41d, and the moving member 42 and the movable protrusion 43 are also moved in the arrow D direction. Thus, the movable protrusion 43 and the engagement wing 44 are disengaged.

  When the operation of the internal combustion engine is finished, the first control valve 26 of the air pipe 25 provided in the compressed air tank 22 shown in FIG. 1 is opened to release the compressed air Ac in the compressed air tank 22 to the atmosphere. Do work. At this time, the second control valve 27 is closed, and the first control valve 26 of the air pipe 25 is opened and the second control valve 27 is closed as shown in FIG. In this state, the compressed air Ac is introduced into the air chamber 41b and overcomes the urging force of the spring body 41d, the piston wall 41c moves in the arrow C direction, and the moving member 42 and the movable protrusion 43 also move in the arrow C direction. Move to. When this movement proceeds to some extent, the movable protrusion 43 comes into contact with and engages with the engaging wing 44, and the movable protrusion 43 presses the engaging wing 44.

  Further, when the compressed air Ac is sufficiently supplied to the air chamber 41b and the state shown in FIG. 6 is shifted to the state shown in FIG. 7, the piston wall 41c, the moving member 42 and the movable projection 43 are maximized in the direction of the arrow C. Move as much as possible. During this movement, the distal end side of the engaging wing 44 with which the movable protrusion 43 is engaged is pushed in the direction of arrow C, and the drive shaft 20c of the EGR valve 20 is rotated in the direction of arrow E.

  After moving from the state shown in FIG. 7 to the state shown in FIG. 8, that is, after the movable protrusion 43 has moved to the maximum in the direction of arrow C, the second control valve 27 is opened as shown in FIG. In this state, the first control valve 26 is kept open. In this state, the compressed air Ac in the air chamber 41 b is released into the atmosphere via the second control valve 27. Although the first control valve 26 may be closed at this timing, it is necessary to operate the first control valve 26 accordingly, so the first control valve 26 is opened. This is preferable because the number of valve operations is reduced.

  By opening the second control valve 27, the pressure in the air chamber 41b decreases, and the biasing force of the spring body 41d moves the piston wall 41c, the moving member 42, and the movable protrusion 43 in the direction of arrow D, The state shown in FIG. 8 is shifted to the state shown in FIG. With this transition, the movable protrusion 43 engages with the adjacent engaging wing 44 and pulls the tip end side of the engaging wing 44 in the direction of arrow D, so that the drive shaft 20c of the EGR valve 20 rotates in the direction of arrow F.

  The drive shaft 20c of the EGR valve 20 is forcibly rotated by the series of opening / closing valve operations of the first control valve 26 and the second control valve 27 shown in FIGS. Therefore, after the EGR valve 20 is closed as shown in FIG. 2, the valve body 20b fixed to the drive shaft 20c remains in contact with the valve seat 20d and rotates around the drive shaft 20c in the E direction. Rotate in the direction.

  6 to 9 are repeated by opening and closing the second control valve 27, so that the valve body 20b remains in contact with the valve seat 20d and the E and F directions around the drive shaft 20c. Can be repeated, so that the stick attached to the valve body 20b and the valve seat 20d can be removed, and the EGR valve 20 can be cleaned.

  Instead of the configuration of the movable protrusion 43 and the engagement wing 44 of the cleaning device 40, one end is rotatably supported by a rotation fulcrum 45a disposed on the distal end side of the moving member 42, and the other end has a rotation fulcrum 46a. A configuration as shown in FIG. 10 may be used, which includes a link 45 and a link 46 that is rotatably supported at one end by the rotation fulcrum 46a and the other end is fixed to the drive shaft 20c. In short, it is only necessary that the reciprocating motion of the moving member 42 generated by the supply control of the compressed air Ac can be converted into a rotational motion.

  With the above configuration, in the cleaning method for the EGR valve of the internal combustion engine, when the operation of the internal combustion engine is finished, the compressed air Ac stored in the compressed air tank 22 is supplied to the cleaning device 40 provided in the EGR valve 20. The EGR valve 20 can be cleaned.

  And according to the cleaning method and the internal combustion engine of the EGR valve of the internal combustion engine, when the operation of the internal combustion engine is stopped and the compressed air AC used in the supercharging assist system 10 is discharged, the compressed air Ac is used. The EGR valve 20 can be cleaned by using it, and the valve main body 20b of the EGR valve 20 can be prevented from sticking to the valve seat 20d with the adhering stick. As a result, the controllability such as the fine opening degree control of the EGR valve 20 can be kept good.

  Further, the compressed air Ac stored in the compressed air tank 22 rotates the valve body 20b of the EGR valve 20 in the closed state around the drive shaft 20c to slide the valve body 20b and the valve seat 20d together. Since the valve 20 is configured to be cleaned, the EGR valve 20 can be easily cleaned with a relatively simple configuration.

  According to the cleaning method for an EGR valve of an internal combustion engine and the internal combustion engine of the present invention, the operation of the internal combustion engine is performed in the internal combustion engine including the turbocharging system and the supercharging assist system for introducing the prestored compressed air into the cylinder. Since the soot adhering to the EGR valve can be removed using the compressed air stored in advance for supercharging assistance when the operation is completed, it can be used for an internal combustion engine mounted on many vehicles.

DESCRIPTION OF SYMBOLS 1 Turbo-type supercharging system 10 Supercharging assistance system 11 Engine main body 12 Intake passage 12a Air intake passage 13 Exhaust passage 15 Turbo supercharger (turbocharger)
15a Compressor 15b Turbine 18 EGR passage 19 EGR cooler 20 EGR valve 20a Case 20b Valve body 20c Drive shaft 20d Valve seat 21 Compressor 22 Compressed air tank 23 Supercharging auxiliary passage 24 Flow path switching device (switching valve)
25 Air piping 26 First control valve 27 Second control valve 40 Cleaning device 41 Piston 42 Moving member 43 Movable projection 44 Engagement blade Ac Compressed air Ge EGR gas

Claims (4)

A turbo-type supercharging system, a supercharging assist system that switches compressed air stored in a compressed air tank in advance into a cylinder by switching from an air intake passage to a supercharging assist passage by a flow path switching device, and an EGR having an EGR valve In a method for cleaning an EGR valve of an internal combustion engine equipped with a system,
When the operation of the internal combustion engine is finished, the compressed air stored in the compressed air tank is supplied to a cleaning device provided in the EGR valve to clean the EGR valve. How to clean the EGR valve.   The EGR valve is cleaned by rotating the valve body of the closed EGR valve around the drive shaft by the compressed air stored in the compressed air tank and sliding the valve body and the valve seat together. The method for cleaning an EGR valve of an internal combustion engine according to claim 1. A turbo-type supercharging system, a supercharging assist system that switches compressed air stored in a compressed air tank in advance into a cylinder by switching from an air intake passage to a supercharging assist passage by a flow path switching device, and an EGR having an EGR valve In an internal combustion engine equipped with a system,
An air pipe for connecting the compressed air tank and the cleaning device for the EGR valve is provided, a control valve for controlling the supply of compressed air to the cleaning device is provided in the air pipe, and the operation of the internal combustion engine is finished. A control device configured to control the control valve to supply the cleaning device with all or part of the compressed air discharged from the compressed air tank to clean the EGR valve An internal combustion engine comprising:   The cleaning device receives the supply of compressed air, rotates the valve body of the EGR valve in the closed state around the drive shaft, and slides the valve body and the valve seat to clean the EGR valve. The internal combustion engine according to claim 3, wherein the internal combustion engine is configured to perform.

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