JP2002039019A - Egr cooler and method for washing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce labor and time required for cleaning an EGR cooler by making it possible to easily carrying out cleaning work without dismounting the EGR cooler. SOLUTION: An EGR cooler comprises tubes 3 and a shell 1 surrounding the tubes 3, wherein cooling water 10 is supplied to and discharged from the inside of the shell 1 and wherein exhaust gas 13 passes through the inside of the tubes 3 to perform heat exchanging between the exhaust gas 13 and the cooling water 10. A cleaner inserting port 16 is provided on a halfway part of a passage (an outlet side EGR pipe 14) for recirculating the exhaust gas 13 passed through the respective tubes 3 so as to face the outlet apertures of the respective tubes 3. A nozzle 18 of a spray gun 17 is inserted from the cleaner inserting port 16 as a cleaning tool. Solvent for washing soot is injected in a mist state from the nozzle 18 toward the outlet openings of the respective tubes 3. The soot deposited in the respective tubes 3 is discharged to the exhaust side by the injection flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EGR cooler which is attached to an EGR device for recirculating exhaust gas of an engine to reduce the generation of nitrogen oxides and cools the exhaust gas for recirculation.

[0002]

2. Description of the Related Art Conventionally, an EGR device for reducing the generation of nitrogen oxides by recirculating a part of exhaust gas from an engine of an automobile or the like to the engine has been known.
In the device, when the exhaust gas recirculated to the engine is cooled, the temperature of the exhaust gas is reduced and its volume is reduced, so that the combustion temperature is reduced without significantly lowering the output of the engine and the nitrogen oxidation is effectively performed. In order to reduce the generation of substances, some engines are equipped with an EGR cooler for cooling the exhaust gas in the middle of a line for recirculating the exhaust gas to the engine.

FIG. 2 is a cross-sectional view showing an example of the EGR cooler. In FIG. 2, reference numeral 1 denotes a cylindrical shell, and at both ends in the axial direction of the shell 1, the end faces of the shell 1 are closed. The plates 2 and 2 are fixed to each other, and both ends of a large number of tubes 3 are fixed to the respective plates 2 and 2 in a penetrating state.
Extends in the axial direction.

In the vicinity of one end of the shell 1,
A cooling water inlet pipe 4 is attached from the outside, and a cooling water outlet pipe 5 is attached from the outside near the other end of the shell 1.
0 is supplied from the cooling water inlet pipe 4 to the inside of the shell 1, flows outside the tube 3, and is discharged from the cooling water outlet pipe 5 to the outside of the shell 1 through the drain tube 11.

Further, bonnets 6 and 6 formed in a bowl shape are fixed to the opposite sides of the shells 1 of the plates 2 and 2 so as to cover the end faces of the plates 2 and 2, respectively. The exhaust gas inlet 7 is provided at the center of the bonnet 6, and the exhaust gas outlet 8 is provided at the center of the other bonnet 6, respectively.
EGR pipe 1 on the inlet side from exhaust manifold not shown
After the exhaust gas 13 led through 2 enters the inside of one bonnet 6 from the exhaust gas inlet 7 and is cooled by heat exchange with cooling water 10 flowing outside the tubes 3 while passing through a number of tubes 3, The EGR pipe 14 which is discharged into the other bonnet 6 and exits from the exhaust gas outlet 8
And is recirculated to an intake manifold (not shown). Reference numeral 15 denotes an EGR valve provided on the EGR pipe 14 on the delivery side.

Further, in the drawing, reference numeral 5a denotes a bypass outlet pipe provided at a position facing the cooling water inlet pipe 4 in the diametrical direction of the shell 1, and the cooling water 10 flows from the bypass outlet pipe 5a.
Is drawn out through the drain tube 11a so that the cooling water 10 does not stagnate at a position facing the cooling water inlet pipe 4.

[0007]

However, in such an EGR cooler, the exhaust gas 13 containing soot passes through the tube 3, so that the soot gradually accumulates in the tube 3 over time. As a result, the cooling efficiency of the exhaust gas 13 is reduced, and as a result, the exhaust gas 13 recirculated to the intake manifold is increased in volume, and the substantial EGR rate is reduced. As a result, the performance of the EGR cooler may be reduced. Inevitable.

Therefore, it has been studied to remove the EGR cooler whose performance has deteriorated in this way and to restore the original performance by cleaning the inside of the tube 3. However, the removal operation of the EGR cooler requires cooling. Since the work of draining the water 10 and the work of removing the water supply / drainage system (the water supply tube 9, the drainage tube 11, and the drainage tube 11a) are required, it takes too much man-hour to clean the EGR cooler, resulting in great labor and labor. There was a problem that it took time.

The present invention has been made in view of the above circumstances, and has as its object to reduce the labor and time required for a cleaning operation so that the cleaning operation can be easily performed without removing the EGR cooler.

[0010]

SUMMARY OF THE INVENTION The present invention comprises a tube,
A shell surrounding the tube, wherein cooling water is supplied and discharged inside the shell, and exhaust gas is passed through the tube to exchange heat between the exhaust gas and the cooling water.
In the GR cooler, a cleaning tool insertion port that can be opened and closed is provided in the middle of a path for recirculating exhaust gas passing through each tube to an intake side so as to face an outlet opening of each tube. It relates to a characteristic EGR cooler.

Thus, when soot is accumulated in the tube due to long-term use and the performance of the EGR cooler is deteriorated, the cleaning tool is inserted from the cleaning tool insertion port and the EGR cooler is inserted. Cleaning work can be performed with the cooler attached, eliminating the need for draining cooling water and removing the water supply / drainage system, greatly reducing man-hours, and the labor and time required for cleaning work. It will be significantly reduced.

When a cleaning tool is inserted from the cleaning tool insertion port to perform a cleaning operation, for example, a jet flow is sprayed from the cleaning tool toward the outlet opening of each tube to deposit in each tube. The soot may be discharged to the exhaust side. More specifically, a nozzle of a spray gun is inserted as a cleaning tool from the cleaning tool insertion port, and the soot is directed toward the outlet opening of each tube from the nozzle. It is possible to inject the cleaning solvent in the form of a mist, and to discharge the soot accumulated in each tube to the exhaust side by the injected flow.

When a spray gun is used as a cleaning tool, it is preferable to use a highly volatile combustible solvent as a solvent for cleaning soot. In this case, the soot is dissolved to remove the soot. The solvent immediately discharged from the tube to the exhaust side is immediately vaporized, so that the wet state in the exhaust gas recirculation path is eliminated at an early stage. It becomes unnecessary.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an embodiment of the present invention, and the portions denoted by the same reference numerals as those in FIG. 2 represent the same components.

The present embodiment relates to an EGR cooler having substantially the same configuration as that shown in FIG. 2 described above, and in the course of recirculating the exhaust gas 13 passing through each tube 3 to the intake side, the outlet of each tube 3 A cleaning tool insertion port 16 that can be opened and closed is provided so as to face the side opening.

That is, in the example shown here, a portion near the bonnet 6 of the exit side EGR pipe 14 is bent to form a corner portion (such a corner portion is originally formed due to layout reasons). In many cases, the cleaning tool insertion port 16 is provided at a position where the corner and the axial extension of the shell 1 intersect.

Here, the cleaning tool insertion port 16 has a conventionally known quick chuck structure which is opened when a nozzle 18 of a spray gun 17 to be described later is inserted and closed when the nozzle 18 is removed. Although it is adopted, a structure in which a screw portion is formed in the cleaning tool insertion port 16 or the like so as to be closed by screwing a closing cap may be used.

The tube 3 can be used for a long time.
When the performance of the EGR cooler is degraded due to the accumulation of soot inside the engine, the engine is stopped and the EGR valve 15 downstream of the cleaning tool insertion port 16 is securely closed. A nozzle 18 of a spray gun 17 is inserted from 16 as a cleaning tool, and a solvent for soot cleaning is sprayed from the nozzle 18 toward the outlet opening of each tube 3 in a mist state. The soot accumulated in the air is discharged to the exhaust side.

Here, the spray gun 17 employed as a cleaning tool may have the same mechanism as that conventionally used for painting and the like, and the solvent contained in the liquid tank 21 is supplied to the air supply tube 19. Pressurized air 20 led by
Is sprayed from the tip of the nozzle 18 in the form of a mist.

It is preferable to use a highly volatile combustible solvent such as alcohol as the solvent. In such a case, the soot is dissolved and discharged together with the soot from the tube 3 to the exhaust side. There is an advantage that the wet state in the EGR pipe 12 on the entry side is quickly eliminated by evaporating the solvent immediately, and furthermore, it is burned off together with the soot when the engine is started, so that there is an advantage that no post-treatment is required.

When the EGR cooler is cleaned in this manner, the spray gun 1 is inserted through the cleaning tool insertion port 16.
Since the washing operation can be performed with the EGR cooler attached while the nozzle 18 of No. 7 is inserted, the cooling water 10 is drained and the water supply / drainage system (water supply tube 9, drain tube 11, drain tube 11a) is provided. This eliminates the need for the work of removing the work and the like, so that the man-hour can be greatly reduced, and the labor and time required for the cleaning work can be remarkably reduced.

The EGR cooler and the method of cleaning the same according to the present invention are not limited to the above-described embodiment, and a cleaning tool insertion port may be provided at an appropriate position on the outlet bonnet. It is also possible to use an air gun as a cleaning tool and clean the inside of each tube only by air blowing without using a solvent. Inject the solvent of
It is also possible to clean the inside of each tube by performing air blowing with an air gun in a state where the inside of each tube is filled with a solvent, and it is possible to make various changes without departing from the scope of the present invention. Of course.

[0024]

According to the EGR cooler and the cleaning method of the present invention described above, the cleaning operation can be easily performed without removing the EGR cooler. And the number of steps can be greatly reduced, and labor and time required for the cleaning operation can be remarkably reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shell 3 Tube 10 Cooling water 13 Exhaust gas 14 Outgoing side EGR pipe 16 Cleaning tool insertion port 17 Spray gun (cleaning tool) 18 Nozzle

Claims (4)

[Claims] 1. A cooling system comprising: a tube; and a shell surrounding the tube, wherein cooling water is supplied to and discharged from the inside of the shell, and exhaust gas is passed through the tube to exchange heat between the exhaust gas and the cooling water. In the EGR cooler described above, a cleaning tool insertion port is provided in the middle of a path for recirculating exhaust gas passing through each tube to the intake side so as to face an outlet opening of each tube. E characterized by the following:
GR cooler. 2. The method for cleaning an EGR cooler according to claim 1, wherein a cleaning tool is inserted from a cleaning tool insertion port, and a jet flow is blown from the cleaning tool toward an outlet opening of each tube. A method for cleaning an EGR cooler, comprising discharging soot accumulated in the exhaust to an exhaust side. 3. The method for cleaning an EGR cooler according to claim 1, wherein a nozzle of a spray gun is inserted from a cleaning tool insertion port, and a solvent for cleaning soot is directed from the nozzle to an outlet opening of each tube. Cleaning method for an EGR cooler, characterized by injecting mist in the form of a mist and discharging the soot accumulated in each tube to the exhaust side by the jet flow. 4. The EG according to claim 3, wherein a highly volatile combustible solvent is used as the solvent for soot cleaning.
How to clean the R cooler.