JPH06330743A - Preventing corrosion of muffler - Google Patents

Abstract

PURPOSE:To effectively prevent corrosion due to the condensed water on the surface of the inner wall of a muffler, at low cost. CONSTITUTION:A surface active agent is applied to a muffler inner wall surface 2. When the surface active agent is dissolved in the condensed water generated on the muffler inner wall surface, the surface active agent is absorbed into the muffler inner wall surface 2, to form a protective film consisting of hydrophobic groups 5 and 6, and corrosion of the muffler inner wall surface 2 is thus prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing a muffler installed in an exhaust passage of an engine from being corroded by condensed water from the exhaust.

[0002]

2. Description of the Related Art As a conventional muffler corrosion inhibition method, as shown in Japanese Patent Publication No. 3-70092, an adsorbent composed of crystalline zeolite molecular sieve and activated alumina is inserted into the muffler, and the muffler is placed in the muffler. Contact with the inflowing engine exhaust adsorbs the corrosive gas components in the exhaust to suppress the corrosion of the muffler, or as disclosed in Japanese Utility Model Laid-Open No. 4-57224, in the exhaust pipe of the engine. The aqueous solution of the azide compound is supplied to and the inner peripheral surface of the flow path on the downstream side of the supply section is coated with a material having excellent corrosion resistance to prevent the inside of the exhaust pipe from corroding. There was a problem in practice due to the high cost and the time and effort required for implementation.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to effectively prevent corrosion of the inner wall surface of the muffler due to condensed water at low cost.

[0004]

[Means for Solving the Problems] To achieve this purpose,
A method for preventing corrosion of a muffler according to the present invention, a surfactant is added in the muffler, the surfactant is melted in condensed water in the muffler, and the surfactant is condensed with the inner wall surface of the muffler. It is oriented and adsorbed at the water interface.

[0005]

[Function] Therefore, the surface active agent is oriented and adsorbed on the inner wall surface of the muffler immersed in the condensed water to form the protective film on the inner wall surface of the muffler, so that the engine exhaust gas is dissolved in the condensed water and generated. As a result of the sulfate ions and chlorine ions being separated from the inner wall surface of the muffler, the corrosion of the inner wall surface of the muffler by these ions is easily suppressed.

[0006]

EXAMPLES Examples of the present invention will be specifically described below. In general, the corrosion of automobile main muffler is caused by the steam in the exhaust gas being cooled and accumulated as condensed water in the main muffler, and the condensed water causes corrosion and promotes corrosion of sulfate ions, chlorine ions, etc. dissolved in the condensed water. Is the main cause, it is conceivable to form a protective film of a surfactant on the surface of the muffler base material in order to prevent this corrosion.

In order to confirm its performance, as a muffler internal corrosion test, as shown in FIG.
A test piece 2 of a stainless steel plate is placed in the test piece, and a small amount of an aqueous solution of sodium soap which is a sodium salt of a higher fatty acid is added as a surfactant, or the test solution 3 is injected without any aqueous sodium soap solution. The test piece 2 is dipped in the liquid 3.

The test solution 3 was adjusted to have hydrochloric acid ion of 100 ppm, nitrate ion of 20 ppm, sulfite ion of 600 ppm, sulfate ion of 600 ppm, and acetate ion of 800 ppm by adding hydrochloric acid, nitric acid, sulfuric acid, acetic acid, ammonium sulfite and the like. Aqueous solution and lid 4
Thus, the glass container 1 is sealed and the evaporation of the test liquid 3 is regulated.

This glass container 1 is kept at about 80 ° C. for 24 hours by a thermostat (not shown) and then left in a room to be cooled to room temperature. Then, the heating and cooling patterns having the same contents as above are carried out four times, FIG. 2 shows the amount of corrosion that occurred in the test piece 2 when the heating and cooling patterns were repeated 5 times in total. That is, the amount of corrosion of the test piece 2 drastically decreased when the concentration of the surfactant due to sodium soap in the test solution 3 exceeded about 5000 ppm, and the amount of corrosion was about 100%.
It can be seen that the test piece 2 is hardly corroded when it reaches 00 ppm.

Since the metal surface generally has low wettability,
As shown in Fig. 3, the surfactant dissolved in the test liquid 3 is oriented and adsorbed on the surface of the test piece 2 so that the hydrophobic group 5 faces the metal surface side and the hydrophilic group 6 faces the condensed water side, respectively. Therefore, even if sulfate ions and chlorine ions approach, these ions are less likely to reach the surface of the test piece 2 due to the protective film consisting of the hydrophobic groups 5 and hydrophilic groups 6 of the surfactant, so that the surfactant is It is considered that the amount of corrosion of the test piece 2 was significantly reduced as described above as compared with the case where there was no rust, and rusting was suppressed.

Next, in order to adapt to the high temperature condition when the engine exhaust is led to the muffler, as a heat resistance test of the surfactant, sodium soap is kept at a constant processing temperature for about 30 minutes respectively, When the sodium soap was dissolved in the test solution 3 shown in FIG. 1 so that the surfactant concentration in the test solution 3 became 10000 ppm, and in this state, the same heating and cooling patterns as those of the corrosion test were repeated 5 times. The amount of corrosion generated on the test piece 2 is shown in FIG. The dots in the upper left of FIG.
Specimen 2 when no surfactant was added to
An example of the amount of corrosion is shown for reference.

As can be seen from FIG. 4, corrosion of the stainless steel plate, which is the base material of the muffler, does not occur even after the sodium soap as the surfactant is exposed to the high temperature dry condition of 200 ° C. to 400 ° C. Since it is effectively suppressed by the presence of the activator, the corrosion resistance as a muffler can be sufficiently maintained.

It is needless to say that potassium soap and the like can be used as the surface active agent for preventing the corrosion of the muffler, in addition to the above-mentioned inexpensive sodium soap.

To add the surfactant to the muffler, the surfactant is applied in advance to the inside of the muffler, or
It suffices to place the solid surface active agent in the muffler so that it gradually dissolves into the condensed water from the exhaust generated inside the muffler, and it is necessary to constantly inject the solution of the surface active agent into the muffler. There is no.

As a method of applying the surfactant in advance to the inside of the muffler, for example, once the cylindrical shell such as a double winding constituting the muffler is immersed in the solution of the surfactant once, the inner surface of the shell or the overlapping part This means that a small amount of surfactant was applied to the. In this case, since the amount of condensed water from the exhaust inside the muffler is small, the amount of surfactant required for the generation of condensed water can be easily applied by the above application. It is possible to assemble a muffler using this shell because it can be obtained, or since the exhaust inflow pipe and the outflow pipe of the muffler are not directly connected to each other, a surfactant is introduced into the muffler from one or both of the pipes. If you inject the solution of
The solution applied the surfactant to the bottom of the muffler, and in any case, the treatment operation was extremely simple.

As a method for disposing the solid surface-active agent in the muffler, for example, as shown in FIG.
A square bag-shaped net 11 is attached to the lower part of a suitable separator 10 to be assembled inside the muffler, and an appropriate amount of granular or solid surfactant is contained in the net 11, or as shown in FIG. Then, a core 21 made of metal or heat-resistant resin is embedded in the solid surfactant 20, and the core 21 is attached to a lower portion of an appropriate separator 23 inside the muffler by passing a bolt (not shown) into a central hole 22 of the core 21 or welding. Install or Figure 7
, The tip 32 of the L-shaped support portion 31 is embedded in the solid surfactant 30, and the L-shaped support portion 31 is attached to the lower portion of the appropriate separator 33 inside the muffler by bolting or welding. Then, the solid surface active agent 30 is elastically pressed against the bottom of the muffler by the elasticity of the tip 32, and in any case, if the solid surface active agent is arranged at the bottom of the muffler, these solid surface active agents are The agent gradually dissolves in condensed water generated in the muffler and water droplets that have entered the muffler in rainy weather, spreads to the bottom of the muffler, and is further replenished.

Therefore, when a small amount of an inexpensive surfactant is appropriately added to the inside of the muffler as described above, this surfactant dissolves in the condensed water and the like generated in the muffler, and the surfactant is protected on the inner wall surface of the muffler. Since a coating is formed and the protective coating can effectively suppress corrosion of the inner wall surface of the muffler due to sulfate ions or hydrochloric acid ions, the life of the muffler can be easily extended without requiring extra cost.

[0018]

EFFECTS OF THE INVENTION When the method for preventing corrosion of a muffler according to the present invention is carried out, a protective coating consisting of a hydrophobic group of a surfactant is formed on the inner wall surface of the muffler, and the corrosion of the inner wall surface of the muffler is greatly reduced as compared with the conventional method. As a result, the life of the muffler can be easily extended, and since this corrosion prevention method can be easily implemented at low cost, it has the advantage of being easy to put into practical use.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an example of a performance confirmation device of the present invention.

FIG. 2 is a diagram showing test results obtained by the above apparatus.

FIG. 3 is a conceptual diagram of the operation of the present invention.

FIG. 4 is a diagram showing test results by the device.

FIG. 5 is a perspective view of a main part in the embodiment of the present invention.

FIG. 6 is a perspective view of a main part according to another embodiment of the present invention.

FIG. 7 is a perspective view of a main part according to another embodiment of the present invention.

[Explanation of symbols]

 1 Glass Container 2 Test Piece 3 Test Liquid 5 Hydrophobic Group 6 Hydrophilic Group 10 Separator 11 Net 20 Solid Surfactant 23 Separator 30 Solid Surfactant 33 Separator

Claims (2)

[Claims] 1. A surfactant is added to the muffler, and the surfactant is melted in condensed water or the like in the muffler, and the surfactant is oriented and adsorbed on the inner wall surface of the muffler and the condensed water interface. Muffler corrosion prevention method. 2. A surface active agent solution is applied to the inner wall surface of the muffler, and the surface active agent is melted in condensed water or the like inside the muffler, so that the surface active agent is deposited on the inner wall surface of the muffler and the condensed water interface. A method for preventing muffler corrosion that is oriented and adsorbed.