JP2013167204A - Blowby gas treatment device for internal combustion engine - Google Patents

Abstract

Provided is a blow-by gas processing apparatus capable of suppressing the generation of deposits in an intake passage and effectively removing the deposits generated in the intake passage by effectively utilizing moisture contained in the blow-by gas. .
A blow-by gas passage for returning blow-by gas from an internal combustion engine main body to an intake passage has a double-pipe structure of an inner pipe and an outer pipe. The inner tube 32 is formed of a material having a lower thermal conductivity than the outer tube 34. Then, blow-by gas is allowed to flow through both the inner tube 32 and the outer tube 34. According to this, the temperature in the inner pipe 32 is maintained, but the cooling in the outer pipe 34 proceeds from the surroundings. Therefore, the liquefaction of moisture contained in the blow-by gas is promoted in the outer pipe 34, and the outer pipe 34 is cooled. Water 50 generated in the pipe 34 is supplied into the intake passage.
[Selection] Figure 3

Description

  The present invention relates to a blow-by gas processing device configured to return blow-by gas from an internal combustion engine body to an intake passage through a blow-by gas passage.

  An internal combustion engine for automobiles is provided with a blow-by gas processing device for returning blow-by gas generated in a crankcase or a cylinder head to an intake passage. Various inventions have been proposed for blow-by gas processing apparatuses. For example, Patent Document 1 discloses an invention relating to a blow-by gas processing device for an internal combustion engine with a supercharger. In the invention disclosed in this publication, the blow-by gas passage is connected upstream of the compressor in the intake passage, the gas flowing through the blow-by gas passage is cooled by the EGR cooler, and the oil component in the liquefied blow-by gas is blow-by by the mist separator. Separation from the gas takes place.

  Various proposals have also been made regarding the structure of the blow-by gas passage. Patent Documents 2-4 disclose an example in which the blow-by gas passage has a double pipe structure including an inner pipe and an outer pipe. Among these, in the blow-by gas passage disclosed in Patent Document 2, both the inner pipe and the outer pipe are formed of a material having low thermal conductivity, and a heat insulating layer made of an air layer is provided between the pipes. In the one disclosed in Patent Document 3, blow-by gas is caused to flow through the inner pipe, and engine cooling water is caused to flow through the outer pipe. On the other hand, in what was disclosed by patent document 4, blowby gas is made to flow into both an inner pipe and an outer pipe.

JP 2007-309229 A JP 2003-120244 A Japanese Patent Laid-Open No. 07-208142 Japanese Utility Model Publication No. 05-030410

  By the way, in a blow-by gas processing apparatus, the oil component contained in blow-by gas may adhere to an intake passage, and may become a deposit. In particular, in the configuration in which blow-by gas is returned upstream of the compressor disclosed in Patent Document 1, deposits are likely to occur in a high load region where the outlet temperature of the compressor rises. The generation of deposits inside the compressor causes a vicious cycle in which the generation of deposits is accelerated because the compressor efficiency is lowered and the outlet temperature of the compressor is further increased.

  From the viewpoint of intake efficiency of the internal combustion engine and from the viewpoint of compressor efficiency, it is desirable to suppress the generation of deposits in the intake passage as much as possible, and to remove the generated deposits as much as possible. However, techniques that satisfy such demands are not employed in the blow-by gas processing apparatuses that have been proposed in the past, including the above-mentioned patent documents. In the case of the blow-by gas processing apparatus disclosed in Patent Document 1, although the oil component is liquefied and separated from the blow-by gas by the mist separator, the inflow of the oil component into the intake passage can be suppressed, It is not possible to suppress the generation or to remove the deposit once generated.

  On the other hand, the inventors of the present application have found that water supply is effective for the above problem in the inventive process. By mixing water with the oil in the blow-by gas, it is possible not only to prevent the temperature of the oil from rising, but to suppress the generation of deposits, and it is also possible to wash away the deposits when the water collides with the deposits. It has also been confirmed by experiments that water is allowed to flow into a compressor whose efficiency has been lowered due to deposit adhesion, whereby the deposited deposit is removed and the pressure drop in the compressor is restored.

  As a method of supplying an appropriate amount of water into the intake passage, the inventors of the present application have studied to effectively use the moisture contained in the blow-by gas as well as the oil. The blow-by gas generated from the internal combustion engine main body contains a considerable amount of moisture in the state of water vapor. Therefore, liquid water can be obtained by cooling and liquefying this. However, simply cooling the blow-by gas passage may cause another problem that the blow-by gas passage freezes at low temperatures.

  The present invention has been made in view of such problems, and by effectively utilizing the moisture contained in the blow-by gas, the occurrence of deposits in the intake passage is suppressed, and the occurrence occurred in the intake passage. An object of the present invention is to provide a blow-by gas processing apparatus capable of removing deposits.

  In order to achieve the above object, in the blow-by gas processing apparatus provided by the present invention, the blow-by gas passage for returning the blow-by gas generated in the internal combustion engine main body, that is, the crankcase or the cylinder head, to the intake passage is an inner pipe and an outer pipe. And a double-pipe structure. The inner tube is made of a material having a lower thermal conductivity than the outer tube, and blowby gas flows through both the inner tube and the outer tube. According to this, the temperature in the inner pipe is maintained, but the cooling in the outer pipe proceeds from the surroundings, so that the liquefaction of moisture contained in the blow-by gas is promoted in the outer pipe, and the water generated in the outer pipe is The air is supplied into the intake passage.

  The inner tube is preferably formed of a material having a lower thermal conductivity than water, such as a resin. According to the selection of such a material, a particularly high effect can be obtained with respect to the heat insulation in the inner pipe. On the other hand, the outer tube is preferably made of a material having a higher thermal conductivity than ice, such as carbon steel. According to the selection of such a material, a particularly high effect can be obtained with respect to the cooling performance in the outer tube.

  ADVANTAGE OF THE INVENTION According to this invention, the water | moisture content contained in blowby gas can be used effectively in suppression of the generation | occurrence | production of the deposit in an intake passage, and the removal of the deposit generate | occur | produced in the intake passage.

It is a figure which shows the structure of the internal combustion engine to which the blowby gas processing apparatus was applied in embodiment of this invention. It is a cross-sectional view of the blow-by gas passage concerning an embodiment of the invention. It is a longitudinal cross-sectional view which shows the internal state at the time of normal temperature of the blowby gas channel | path concerning embodiment of this invention. It is a longitudinal cross-sectional view which shows the internal state at the time of the low temperature of the blowby gas channel | path concerning embodiment of this invention. It is a figure which shows the specific example of the support method of the inner pipe | tube of the blow-by gas passage concerning embodiment of this invention.

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

  FIG. 1 is a diagram showing a configuration of an internal combustion engine to which the blow-by gas processing apparatus of the present invention is applied in the present embodiment. In this internal combustion engine, the internal combustion engine body 2 is configured as a gasoline engine. An intake passage 10 is connected to the internal combustion engine body 2 via an intake manifold 4, and an exhaust passage 20 is connected via an exhaust manifold 6. A turbocharger compressor 12 is attached downstream of the air cleaner 14 in the intake passage 10. An intercooler 16 and a throttle valve 18 are provided downstream of the compressor 12 in the intake passage 10. On the other hand, a turbocharger turbine 22 is attached to the exhaust passage 20. The turbine 22 is provided with a waste gate valve 24 that bypasses the turbine 22. A catalyst device 26 and a muffler 28 are provided downstream of the turbine 22 in the exhaust passage 20. In this engine system, blow-by gas generated in the crankcase and cylinder head of the internal combustion engine body 2 is returned to the upstream side of the compressor 12 in the intake passage 10 via the blow-by gas passage 30.

  FIG. 2 is a cross-sectional view of the blow-by gas passage 30 shown in FIG. The blow-by gas passage 30 has a double tube structure of an inner tube 32 and an outer tube 34. The blow-by gas flows through both the inner pipe 32 and the outer pipe 34.

  The inner tube 32 is formed of a material having a lower thermal conductivity than the outer tube 34. Specifically, the inner tube 32 is made of resin, and the outer tube 34 is made of carbon steel. The thermal conductivity of the resin is as low as 0.2 W / mK, which is lower than the thermal conductivity of water (0.58 W / mK). Therefore, the inner pipe 32 functions as a heat insulating material for the blow-by gas flowing through the inner pipe 32. On the other hand, the thermal conductivity of carbon steel is as high as about 40 W / mK, which is much higher than the thermal conductivity of ice (2.2 W / mK). Therefore, the outer tube 34 functions as a cooling layer that promotes heat radiation from the blow-by gas flowing through the outer tube 34 to lower its temperature and liquefy the moisture contained in the blow-by gas.

  The operation of the blowby gas passage 30 configured as described above will be described with reference to FIGS. 3 and 4. FIG. 3 is a longitudinal sectional view showing an internal state of the blow-by gas passage 30 at normal temperature. FIG. 4 is a longitudinal sectional view showing an internal state of the blow-by gas passage 30 at a low temperature. In each figure, the arrow indicated by reference numeral 40 indicates the flow of blow-by gas in the inner pipe 32, and the arrow indicated by reference numeral 42 indicates the flow of blow-by gas in the outer pipe 34.

  First, the operation at normal temperature will be described with reference to FIG. When the outer tube 34 is formed of a material having high thermal conductivity at normal temperature, heat release from the blow-by gas flowing through the outer tube 34 is promoted, and water vapor contained in the blow-by gas is liquefied in the outer tube 34. Thus, water 50 is generated in the outer pipe 34, and this water 50 is supplied upstream of the compressor 12 in the intake passage 10. The liquid water flows into the compressor 12 together with the intake air, and the water collides with the deposit generated in the compressor 12, whereby the deposit is peeled off and removed from the compressor 12.

  When the temperature is low, heat radiation from the inside to the outside of the outer tube 34 is further promoted. And as shown to (a) of FIG. 4, the water | moisture content contained in the blowby gas which flows through the inside of the outer pipe | tube 34 freezes, and the ice 52 is generated. As the blow-by gas containing moisture flows in, the ice 52 grows and eventually completely closes the flow path inside the outer tube 34 as shown in FIG. 4B. When the flow path of the blow-by gas is blocked by the ice 52, the flow of the blow-by gas stops and the inflow of moisture stops, so that the growth of the ice 52 stops there.

  On the other hand, since the inner tube 32 is formed of a material having a low thermal conductivity, that is, a material having a high heat insulating property, heat radiation to the outside is suppressed. Furthermore, since the thermal conductivity of the ice 52 is lower than the thermal conductivity of the carbon steel forming the outer tube 34, the layer of ice 52 formed inside the outer tube 34 acts as a heat insulating layer for the inner tube 32. To do. As a result, the water does not freeze inside the inner tube 32 and ice is not generated, and even if the outer tube 34 is closed by the ice 52, the flow of the blow-by gas is prevented in the inner tube 32. Maintained.

  In the case shown in FIG. 4, the supply of water in the liquid state to the intake passage 10 is reduced or stopped when the moisture becomes ice 52 and stops in the outer pipe 34. However, when the outside air temperature is so low that the inside of the outer pipe 34 is frozen, the temperature of the air flowing into the compressor 12 is also lowered. For this reason, the internal temperature of the compressor 12 remains low even when the internal combustion engine is heavily loaded, and no deposit is generated even if the inflow of water is reduced or stopped.

  Finally, a method for supporting the inner pipe 32 in the blow-by gas passage 30 will be described with reference to FIG. FIG. 5 shows six examples (a) to (f) as specific examples of the method for supporting the inner tube 32. In the example (a), the inner tube 32 is supported from a plurality of directions by a support member 60 made of an elastic material so as to float the inner tube 32 with respect to the outer tube 34. In the example (b), the inner tube 32 is supported by the support member 62 made of an elastic material so that the inner tube 32 is pressed against the inner wall of the outer tube 34. In the example (c), the inner tube 32 is supported from both sides by a metal or resin support member 64 so that the inner tube 32 is floated with respect to the outer tube 34. In the example (d), the inner tube 32 is supported so that the inner tube 32 is pressed against the inner wall of the outer tube 34 by a support member 66 made of metal or resin. In the example (e), the inner tube 32 is supported by a metal or resin support member 68 having a shape different from that of the example (d). In the example (f), the inner tube 32 is supported by a support member 70 that is a combination of an elastic material component and a metal or resin component. In the present embodiment, any support method in these examples may be adopted.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the double pipe structure is not used in the entire section of the blow-by gas passage 30, but only the single pipe structure, that is, the outer pipe 34 may be provided in the vicinity of the outlet connected to the intake passage 10. Further, instead of completely separating the inside of the inner tube 32 and the inside of the outer tube 34, a hole for connecting the inside of the inner tube 32 and the inside of the outer tube 34 may be provided in the tube wall of the inner tube 32. Good.

  Further, the present invention can be applied to an internal combustion engine other than a gasoline engine, for example, a diesel engine, and can be applied not only to an internal combustion engine with a supercharger but also to a naturally aspirated internal combustion engine.

2 Internal combustion engine body 10 Intake passage 12 Compressor 30 Blow-by gas passage 32 Inner pipe 34 Outer pipe 40 Gas flow in inner pipe 42 Gas flow in outer pipe 50 Water 52 Ice 60, 62, 64, 66, 68, 70 Support member

Claims (4)

A blow-by gas processing device for an internal combustion engine configured to return blow-by gas from the internal combustion engine body to the intake passage through the blow-by gas passage,
The blow-by gas passage has a double pipe structure of an inner pipe and an outer pipe, and the inner pipe is formed of a material having a lower thermal conductivity than the outer pipe, and blow-by gas is provided in both the inner pipe and the outer pipe. The blow-by gas processing device for an internal combustion engine, wherein   2. The blow-by of the internal combustion engine according to claim 1, wherein the inner pipe is made of a material having a lower thermal conductivity than water, and the outer pipe is made of a material having a higher thermal conductivity than ice. Gas processing device.   The blow-by gas processing apparatus for an internal combustion engine according to claim 2, wherein the inner pipe is made of resin, and the outer pipe is made of carbon steel.   The internal combustion engine according to any one of claims 1 to 3, wherein the internal combustion engine is an internal combustion engine with a supercharger, and the blow-by gas passage is connected to an upstream side of a compressor in the intake passage. Blow-by gas processing equipment.

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