JPH0417711A - Intake and exhaust system of engine - Google Patents

Abstract

PURPOSE:To perform EGR(Exhaust Gas Recycle) while removing particulate by providing a communicating pipe communicating to an air intake side so as to branch from an exhaust pipe on the upper stream side of a main filter and installing an auxiliary filter and control valve in the communicating pipe. CONSTITUTION:A main particulate filter 15 is installed in the exhaust pipe 14 of an engine 10. In addition, an EGR pipe 16 communicating to an intake manifold 11 is provided so as to branch off the exhaust pipe 14 on the upper stream of the main particulate filter 15. An auxiliary particulate filter 17 and control valve 18 are installed in the EGR pipe 16. Owing to this constitution, the exhaust gas, from which particulate is removed by the auxiliary particulate filter 17, can be returned to the intake manifold 11 through the EGR pipe 16 by opening the control valve 18. Therefore, since the exhaust gas is thus purified, EGR becomes possible.

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to an engine intake and exhaust system, and in particular, a particulate filter is attached to an engine exhaust pipe, and the particulate filter captures and removes particulates contained in exhaust gas. This invention relates to an intake and exhaust system for an engine. K Summary of the invention In an engine in which a particulate filter is attached to an exhaust pipe and the particulate filter removes particulates from exhaust gas, the particulate filter branches from the exhaust pipe on the upstream or downstream side of the particulate filter. A communication pipe is provided that communicates with the intake side, and this communication pipe allows EGR (Exhaust
Gas Recirculation (exhaust gas recirculation) is performed, and exhaust gas that does not contain particulates is returned to the intake side.

[Conventional technology]

EG is one of the measures against diesel engine exhaust gas.
R is known. EGR extracts a portion of exhaust gas from the exhaust system and returns it to the intake side. This lowers the relative oxygen concentration of the intake air, suppresses combustion temperature, and reduces the amount of nitrogen oxides produced. It was designed to do so. [Problems to be Solved by the Invention] When such EGR is performed in a diesel engine, particulates contained in the exhaust gas are also returned to the intake side. Such particulates may cause the EGR valve to stick,
This will cause problems such as wear of the cylinder liner and piston rings attached to the piston. Particulate filters have been known for removing particulates from diesel engine exhaust gas. The particulate filter is composed of a porous ceramic filter or the like, and when exhaust gas passes through the particulate filter, particulates are captured and removed. Therefore, it is considered to incorporate such a particulate filter into an EGR device, but if particulates accumulate in the filter, gas flow resistance increases, so it is necessary to remove the accumulated particulates by some means. There must be. The present invention was made in view of these problems, and enables EGR that removes particulates contained in exhaust gas and returns them to the intake side, and also enables EGR that removes particulates contained in exhaust gas and returns them to the intake side. It is an object of the present invention to provide a device that enables backwashing of a particulate filter. Means for Solving Problem K] A first invention includes a main particulate filter attached to an exhaust pipe of an engine, and an upstream side of the main particulate filter communicating with an intake side so as to branch from the exhaust pipe. A communicating pipe is provided, an auxiliary particulate filter and a control valve are attached to the communicating pipe, and the main particulate filter and the auxiliary particulate filters 1 to 1 are connected to each other.
Backwashing air nozzles are provided on the downstream side of each filter. Further, a second invention provides a particulate filter that is attached to an exhaust pipe of an engine, and a communication pipe that is connected to the intake side so as to branch from the exhaust pipe on the downstream side of the particulate filter, and the communication pipe III'm
It is designed to connect a valve.

[Effect]

Therefore, according to the first invention, by opening the control valve, it becomes possible to return exhaust gas to the intake side through the communication pipe, and EGR is performed. At this time, particulates contained in the exhaust gas are removed by an auxiliary particulate filter attached to the communication pipe. According to the second invention, by opening the control valve, it becomes possible to return exhaust gas to the intake side through the communication pipe,
This allows EGR to be performed. Moreover, since the communicating pipe line is connected to branch from the exhaust pipe on the downstream side of the particulate filter, the exhaust gas from which particulates have been removed by the particulate filter is returned to the intake side. K Embodiment FIG. 1 shows an engine intake and exhaust system according to a first embodiment of the present invention, in which an intake manifold 11 and an exhaust manifold 12 are provided on both sides of a cylinder block of a diesel engine 10, respectively. installed. An intake pipe 13 is attached to the intake manifold 11, and an exhaust pipe 14 is attached to the exhaust manifold 12. Furthermore, a main particulate filter 15 is connected to the exhaust pipe 14 connected to the exhaust manifold 12.
Particulates in the exhaust gas are removed by this method. On the upstream side of the particulate filter 15, the exhaust pipe 14 or the casing of the filter 15 has an EGR
The vibrators 16 are connected in a branched manner. An auxiliary particulate filter 17 is connected in the middle of this EGR vibe 16. Zarani EG
A control valve 18 is connected to the R via 16 downstream of the auxiliary particulate filter 17, and is also connected to the intake manifold 11. A butterfly valve 19 is attached to the intake pipe 13, and its rotation is controlled by an actuator 20. Next, the backwashing devices for the main particulate filter 15 and the auxiliary particulate filter 17 will be explained.The backwashing devices Ha for these filters 15 and 17 are each comprised of air nozzles 21 and 22. These air nozzles 21, 22 are each connected to an air tank 23 by an air line 24, 25. Each of the air lines 24, 25 is provided with a solenoid valve 26, 27. These electromagnetic valves 26 and 27 are controlled by a controller 28. Further, the controller 28 controls the control valve 18 and the actuator 20. In the above configuration, exhaust gas generated by the operation of the engine 10 is discharged through the exhaust manifold 12 and the exhaust pipe 14. At this time, particulates in the exhaust gas are removed by a particulate filter 15 connected to the exhaust pipe 14. Also, EGR of engine 10
When performing this, the control valve 18 is opened based on instructions from the controller 28. When the control valve 18 is opened, a portion of the exhaust gas flows from the exhaust pipe 14 to the EGR vibe 16.
The air is returned to the intake manifold 11 side through the air. At this time, particulates contained in the exhaust gas are removed by the auxiliary particulate filter 17, and the exhaust gas containing particulates is prevented from being returned to the intake side. Since particulates in the exhaust gas are removed by the auxiliary particulate filter 17 when performing EGR, sticking of the control valve 18 and wear of the cylinder liner, piston ring, etc. are reliably prevented. That will happen. Further, when strong negative pressure is required on the intake pipe 13 side, the butterfly valve 19 is throttled by the controller 28. When particulates accumulate on the main particulate filter 15 and the auxiliary particulate filter 17, gas flow resistance increases, and eventually the gas becomes unable to flow. To avoid this situation, each filter 15.17 is backwashed by an air nozzle 21.22. When backwashing the main particulate filter 15, the controller 28 opens the control valve 18, and the solenoid valve 26 is opened according to instructions from the controller 28. Then, the compressed air in the air tank 23 is injected from the downstream side to the main particulate filter 15 through the air nozzle 21. Therefore, the particulates captured by the particulate filter 15 will fall from the filter 15. The fallen particulates fall onto the heater 30 on the inlet side of the auxiliary particulate filter 17. Therefore, by energizing the heater 30, the main particulate filter 15
Particulates that fall from the ground will be burned. Further, soot that cannot be burned by the heater 30 is captured by the auxiliary particulate filter 17. Next, the auxiliary particulate filter 17 is backwashed using the air nozzle 22. At this time, the control valve 18 is closed by the controller 28. At the same time, a solenoid valve 27 is opened by a controller 28, and air is blown onto the auxiliary particulate filter 17 from the opposite direction by an air nozzle 22, so that the soot on the filter 17 is blown away toward the inlet side, thereby cleaning it. As described above, according to this embodiment, the intake/exhaust system is such that the filter 17 is attached to the EGR via 16 that releases the air to the intake side, and the air injected from the air nozzle 21 is assisted when the main particulate filter 15 is backwashed. The soot is returned to the intake side through a particulate filter 17 to increase soot collection efficiency. That is, since there are two filter systems and the unused filter is backwashed, it is possible to increase the backwashing efficiency of the backwash type particulate filter 15. Note that the auxiliary particulate filter 17 and the heater 30 may be integrated. That is, the heater 30 may be integrated by forming the filter 17 itself from a heating element. Next, a second embodiment will be explained with reference to FIG. In the second embodiment, a particulate filter 15 is connected to the exhaust pipe 14, and an EGR via 16 is connected downstream of the particulate filter 15 so as to branch from the exhaust pipe 14.
A control valve 18 is connected to this EGR pipe 16, and the tip of the EGR via 16 is connected to the intake manifold 11. According to such a device, when performing EGR, the control valve 18 may be opened by the controller 28. Then, a part of the exhaust gas passing through the exhaust pipe 14 is transferred to the EGR via 1.
6 to the intake manifold 11 side, which allows part of the exhaust gas to be returned to the intake side.
R will be performed. Furthermore, since the extracted exhaust gas has passed through the particulate filter 15, it becomes possible to return the exhaust gas from which particulates have been removed by the particulate filter 15 to the intake side. Therefore, problems caused by returning exhaust gas containing particulates to the intake side, such as sticking of the control valve 18 and wear of the cylinder liner and piston ring, can be reliably prevented.

【Effect of the invention】

In the first invention, a communication pipe is provided on the upstream side of the main particulate filter in the exhaust pipe of the engine and communicates with the intake side so as to branch from the exhaust pipe, and an auxiliary particulate filter is provided in the communication pipe. Install the control valve and
Further, air nozzles for backwashing are provided downstream of the main particulate filter and the auxiliary particulate filter, respectively. Therefore, by opening the control valve, it becomes possible to return exhaust gas to the intake side via the communication pipe line, and EGR is performed. Furthermore, during EGR, particulates are removed by the auxiliary particulate filter, making it possible to return clean exhaust gas to the intake side. In addition, since a main particulate filter and an auxiliary particulate filter are provided, it is possible to backwash the unused filter with the corresponding air nozzle, making it easy to regenerate the pair of filters. become. According to the second invention, a communication pipe is provided downstream of the particulate filter attached to the exhaust pipe and communicates with the intake side so as to branch from the exhaust pipe, and the control valve is provided in the communication pipe. It is designed to connect. Therefore, it is possible to pass through the particulate filter installed in the exhaust pipe and return the exhaust gas from which particulates have been removed to the intake side. This makes it possible to prevent the problem of liner and piston ring wear.

[Brief explanation of the drawing]

FIG. 1 is a piping diagram showing an intake and exhaust system for an engine according to a first embodiment, and FIG. 2 is a piping diagram for an intake and exhaust system for an engine according to a second embodiment. The names of the main parts in the drawings are as follows. 14...Exhaust pipe 15...Main particulate filter 16...
... EGR pipe 17 ... Auxiliary particulate filter 18 ...
... Control valve 21.22 ... Air nozzle 26.27 ... Solenoid valve

Claims (1)

[Claims] 1. A main particulate filter is attached to the exhaust pipe of the engine, and a communication pipe is provided upstream of the main particulate filter to branch from the exhaust pipe and communicate with the intake side. An intake/exhaust system for an engine, characterized in that an auxiliary particulate filter and a control valve are attached to the communication pipe, and backwashing air nozzles are provided downstream of the main particulate filter and the auxiliary particulate filter, respectively. Device. 2. Attach a particulate filter to the exhaust pipe of the engine, and provide a communication pipe downstream of the particulate filter that branches from the exhaust pipe and communicates with the intake side, and connect a control valve to the communication pipe. An intake and exhaust system for an engine, characterized in that it is configured to do so.