JP2009281317A - Intake pipe structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost intake pipe structure of an internal combustion engine which is reliable in a low-temperature environment and capable of solving a problem wherein a large ice block created in the intake pipe is likely to damage an important part of an intake system. <P>SOLUTION: In the intake pipe structure of the internal combustion engine provided with an intake pipe part 72 forming an intake passage 21a of the engine 10, the intake pipe part 72 is provided with a projection part 72p protruding from an inner bottom wall surface part 21b into the intake passage 21a and the inner bottom wall surface part 21b is separated into a plurality of recessed parts 21c near the projection part 72p. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an intake pipe structure of an internal combustion engine, and more particularly, when a turbocharger compressor and other important intake system components are installed, or when blow-by gas is recirculated to an intake passage upstream of the intake system important components. The present invention relates to an intake pipe structure of an internal combustion engine suitable for the above.

  In a vehicular internal combustion engine (hereinafter simply referred to as an engine), a blow-by gas (Blow−) containing unburned air-fuel mixture and burned combustion gas passes through a gap between a cylinder and a piston from a combustion chamber to an upper portion of a crankcase. By Gases), a PCV (Positive Crankcase Ventilation) type blow-by gas reduction device that ventilates the crankcase is equipped to prevent deterioration of engine oil in the engine.

  In an engine equipped with this blow-by gas reduction device, the blow-by gas in the crankcase is separated into gas and liquid through an oil separator, and then returned to the intake pipe through a PCV hose which is a piping for returning the PCV valve and blow-by gas. It has an intake pipe structure in which one end of the PCV hose is connected to the intake pipe.

  In addition, when the intake air temperature is low, such as when idling at low temperatures, icing is likely to occur on the inner wall of the intake pipe near the connection portion of the PCV hose where the PCV recirculation gas containing moisture enters the intake pipe. The PCV gas recirculation passage near the connection to the intake pipe is blocked by freezing, resulting in poor recirculation of blow-by gas and the occurrence of a situation where the turbocharger compressor is damaged by a large ice block. The idea to make is made.

  As a conventional intake pipe structure of this type of internal combustion engine, in order to prevent malfunction of the intake control valve due to icing such as icing or frost adhesion, or when the intake air temperature or cooling water temperature is low, or excessive water vapor in the intake pipe It is known that when the condition is satisfied, the opening degree of the intake control valve is temporarily increased to blow out condensation, frost, ice, or the like (for example, see Patent Document 1).

Also, a tube that recirculates the blow-by gas to the intake passage has a double-pipe structure made of a low thermal conductivity material and a heat insulating air layer is formed inside (see, for example, Patent Document 2), and a hot water heating hose close to the PCV valve What was provided (for example, refer patent document 3) etc. are known.
JP-A-2005-42682 JP 2003-120244 A Japanese Patent Laid-Open No. 10-121937

  However, in the conventional intake pipe structure of an internal combustion engine in which condensation, frost, ice, etc. are blown away by temporarily increasing the opening of the intake control valve, a temperature sensor is used to predict valve malfunction. In addition, there is a problem in that the determination of excessive water vapor conditions, control means for temporarily increasing the valve opening, and the like are required, resulting in high costs.

  Also, the conventional intake pipe structure of an internal combustion engine in which the blow-by gas recirculation tube is made of a double pipe structure made of a low thermal conductivity material and an adiabatic air layer is formed therein is complicated in structure and expensive. There was a problem.

  In addition, in the conventional intake pipe structure of an internal combustion engine, when a turbocharger is provided, for example, water vapor generated from PCV gas is generated in the vicinity of the connection portion of the blowby gas recirculation passage to the intake passage. When the internal combustion engine is warmed up, a turbo-type supercharger forms a large ice block that is formed on the inner wall of the intake pipe where the vertical position is lowest, and is formed by water that accumulates at the lowest position in the vertical direction. I couldn't solve the problem of getting in the compressor and damaging the impeller.

  Furthermore, even in a conventional internal combustion engine intake pipe structure provided with a hot water heating hose close to the PCV valve, a large ice block is peeled off during warm-up, and the compressor and other important components of the intake system of the turbocharger are removed. There was a problem of being hurt.

  The present invention has been made to solve the above-described conventional problems, and is reliable in a low-temperature environment that can solve the problem of easily damaging important components of the intake system due to large ice blocks formed in the intake pipe. An object of the present invention is to provide a low-cost internal combustion engine intake pipe structure excellent in performance.

  In order to achieve the above object, the intake pipe structure of an internal combustion engine according to the present invention is (1) an intake pipe structure of an internal combustion engine provided with an intake pipe body that forms an intake passage of the internal combustion engine. It has a projection protruding into the intake passage from the inner wall surface of the tube forming the intake passage, and the inner wall surface of the tube is partitioned into a plurality of recesses in the vicinity of the protrusion.

  With this configuration, even if the moisture in the intake passage freezes on the inner wall surface of the pipe, the ice is divided into a plurality of recesses by projections protruding into the intake passage, resulting in a large ice block. There is no. Therefore, a large ice block peeled off in the intake pipe will not damage important parts of the intake system, and a complicated and costly configuration for preventing freezing will not occur.

  In the intake pipe structure of the internal combustion engine having the configuration described in (1) above, (2) the intake pipe main body is located upstream of the compressor of the turbocharger installed in the internal combustion engine in the intake passage. It is preferable that an intake passage is formed and connected to an inlet portion of the compressor, and the protruding portion protrudes into the intake passage from a pipe inner wall surface portion forming the upstream intake passage.

  With this configuration, even if the water in the intake passage on the upstream side freezes on the inner wall surface of the pipe, the ice is divided into a plurality of recesses by projections protruding into the intake passage. Even if it enters the compressor of the supercharger, the size is such that it can be easily crushed. Therefore, the compressor is not damaged by a large ice block peeled off in the intake pipe, and a complicated and costly configuration for suppressing freezing is not caused.

  In the intake pipe structure of the internal combustion engine having the configuration described in the above (1) and (2), (3) it is preferable that the protruding portion forms a protrusion extending in the passage length direction of the intake passage.

  With this configuration, the protrusion can be easily formed at low cost inside the intake pipe.

  The intake pipe structure of the internal combustion engine having the configuration described in the above (1) and (2) is (4) a structure in which the protruding portion extends in a direction intersecting the passage length direction of the intake passage. Even preferred.

  With this configuration, the water accumulation in the intake pipe is different between the plurality of recesses, and a plurality of ice blocks are hardly generated at the same time. In addition, the protrusion mentioned here may be straight or curved.

  In the intake pipe structure of the internal combustion engine having the configuration described in (4) above, (5) the protrusion may extend in a direction orthogonal to the passage length direction of the intake passage.

  In this case, the peripheral part of the ice block formed in the plurality of recesses becomes thinner and more easily crushed.

  In the intake pipe structure of the internal combustion engine having the configuration described in (1) to (5) above, (6) the protrusion is disposed in a specific passage section located on the lower side in the vertical direction of the intake pipe main body. It is desirable.

  With this configuration, the ice block is generated by being divided into a plurality of recesses in the specific passage section where the large ice block is easily formed, and the size of the ice block is reduced, so that the intake system is warmed up when the internal combustion engine is warmed up. The important parts of the compressor such as the turbocharger compressor impeller are not damaged.

  In the intake pipe structure of the internal combustion engine having the configuration described in (1) to (6) above, (7) a return hole for returning the blow-by gas from the inside of the internal combustion engine to the intake passage is provided in the intake pipe body. The specific passage section formed may include a range from the vicinity of the end of the intake pipe body on the downstream side in the intake direction to the position of the return hole in the intake direction where the return hole is formed.

  With this configuration, even if ice blocks are easily formed by moisture contained in the blow-by gas, the ice blocks are divided into a plurality of recesses in the specific passage section, and do not damage important components of the intake system, such as the compressor impeller. .

  In the intake pipe structure of the internal combustion engine having the configuration described in (1) to (7) above, (8) the protrusions are separated from each other in the intake passage and have the same height in the vertical direction. It is preferable that it is constituted by a plurality of protrusions.

  With this configuration, the surface of the ice block formed in the plurality of recesses can be suppressed to a uniform height in the vicinity of the height positions of the plurality of protrusions.

  According to the present invention, even if the water in the intake passage freezes on the inner wall surface of the pipe, the ice is divided into a plurality of concave portions by the protruding portions protruding into the intake passage, and the peeled ice blocks are large ice blocks. In a low-temperature environment that can solve the problem of easily damaging important components of the intake system due to large ice blocks formed in the intake pipe, without using a complicated and expensive configuration to suppress icing. It is possible to provide a low-cost internal combustion engine intake pipe structure excellent in reliability.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a front sectional view of a principal part of an intake pipe structure for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment.

  First, the configuration will be described.

  Since the intake pipe structure of the internal combustion engine of the present embodiment is configured as shown in FIGS. 1 and 2 and is installed in the engine 10 shown in FIG. 3, the overall configuration of the engine 10 will be described. 3 includes a cylinder head 12, a cylinder block 13, and a crankcase 14 to which a head cover 11 is attached. A plurality of cylinders 15 (1 in FIG. Only one is shown).

  A piston 16 is accommodated in each cylinder 15, and although not shown in detail, a crankshaft (not shown) in the crankcase 14 is connected to the piston 16 via a connecting rod. Further, a valve mechanism is housed in the cylinder head 12, and this valve mechanism is driven based on the power from the crankshaft (or independently in conjunction with the crankshaft). .

  An oil pan 18 is provided at the lower portion of the crankcase 14 and contains lubricating oil L therein. Although not shown in detail, the engine 10 is provided with an oil pump such as a gear pump that is driven on the basis of the power of the crankshaft. Each rotating / sliding part such as a valve mechanism camshaft, rocker arm or crankshaft bearing is lubricated.

  In each cylinder 15, air is sucked into the combustion chamber 17 formed above the piston 16 in the drawing through the intake pipe 21 according to the stroke of the piston 16 and fuel is injected by an injector (not shown). The exhaust gas after combustion inside is exhausted from the exhaust pipe 22.

  A turbocharger 25 is provided between the intake pipe 21 and the exhaust pipe 22.

  As shown in FIG. 1 and FIG. 3, the turbocharger 25 is a known one that rotates an exhaust turbine 27 by exhaust energy and rotates an impeller 26a of a compressor 26 connected thereto, and for example, when necessary by switching passages. Only inserted on the air supply / exhaust path. In addition to the turbocharger 25, the intake pipe 21 is provided with an air cleaner 31, an intercooler 32, a throttle valve 33, and an intake pressure sensor 34 for detecting the pressure in the intake pipe 21 from the upstream side. Yes.

  On the other hand, as shown in FIG. 3, the engine 10 is provided with a ventilation passage (not shown) that communicates from the cylinder head 12 side (inside the head cover) to the crankcase 14, and the inside of the engine 10 is shown in FIG. The air flow is generated in the flow direction indicated by white arrows in FIG.

  Specifically, a known PCV oil separator 41 is attached to the side of the engine 10.

  The PCV oil separator 41 removes oil from blow-by gas recirculated from the upper part of the crankcase 14 to the intake side.

  A PCV hose 58 is provided between the PCV oil separator 41 and the intake pipe 21 on the upstream side of the turbocharger 25. Through the PCV hose 58, the blow-by gas in the upper part of the crankcase 14 is returned to the upstream side of the turbocharger 25.

  The intake pipe structure of the internal combustion engine of this embodiment is a connection pipe that connects the intake pipe 21 upstream of the compressor 26 of the turbocharger 25 to the inlet portion 26b of the compressor 26 in the engine 10 as described above. It is comprised as the part 70 (intake pipe main body).

  As shown in FIGS. 1 and 2, the connecting pipe portion 70 includes a reflux pipe portion 71 to which one end portion 58 d of the PCV hose 58 is connected, and a part of the intake pipe 21 upstream of the turbocharger 25. And an intake pipe portion 72 (intake pipe main body).

  The recirculation pipe portion 71 has a recirculation hole 71 s for recirculating blowby gas from the inside of the engine 10 to the intake passage 21 a on the upstream side, and a recirculation passage 58 a for recirculating the blowby gas from the inside of the engine 10. And a connection portion between the intake passage 21a of the engine 10 is formed.

  Further, the intake pipe portion 72 has a protrusion 72p that protrudes into the intake passage 21a from the inner bottom wall surface portion 21b (pipe inner wall surface portion) located on the lower side in the vertical direction in the intake passage 21a on the upstream side (in the cross section). The inner bottom wall surface 21b is partitioned into a plurality of rectangular recesses 21c in the vicinity of the protrusion 72p.

  Specifically, as shown in FIG. 2, the protrusion 72p includes a plurality of protrusions extending in the passage length direction of the intake passage 21a, for example, a plurality of protrusions having an upward wedge-shaped cross section, that is, a substantially triangular cross section. The plurality of protrusions 72p1 to 72p3 are separated from each other in parallel in the intake passage 21a, and have the same top (ridgeline) height h in the vertical direction. Have. The top height h here is set according to the required volume of the entire plurality of recesses 21c, and is, for example, about 1/5 or less of the inner diameter of the intake pipe 21 (the diameter of the intake passage 21a).

  Further, the protrusion 72p of the intake pipe 21 is disposed in a specific passage section 21z positioned on the lowermost side in the vertical direction of the intake passage 21a on the upstream side, and from the vicinity of the air cleaner 31 to the inlet portion 26b of the compressor 26. In the present embodiment where the position of the intake passage 21a in the vertical direction gradually decreases, for example, a specific passage section 21z is set in the vicinity of one end of the intake pipe 21 connected to the inlet portion 26b of the compressor 26.

  Further, the specific passage section 21z is set so as to include a range from the vicinity of the end portion 72c on the downstream side in the intake direction of the intake pipe portion 72 to the return hole position in the intake direction where the return hole 71s is formed.

  Further, the inlet portion 26b of the compressor 26 is an end portion connected to the end portion 72c on the downstream side in the intake direction of the intake pipe portion 72 and has the same inner diameter as the end portion 72c on the downstream side in the intake direction of the intake pipe portion 72. In addition, the inner peripheral surface has a tapered shape in which the inner diameter decreases as it approaches the impeller 26a.

  Therefore, the plurality of ridges 72p1 to 72p3 extend straight in the specific passage section 21z, and the plurality of rectangular recesses 21c defined by the ridges 72p1 to 72p3 become shallow at the upstream end in the intake direction. And continues to the inner bottom recess 26c on the inlet 26b side of the compressor 26 that becomes shallower at the downstream end in the intake direction.

  The total volume of the plurality of recesses 21c is set to, for example, about 20 to 30 mL (milliliter) according to the amount of water (maximum value) that is dewed in the intake pipe 21 and accumulated in the specific passage section 21z and is estimated to be frozen. The individual volumes of the plurality of recesses 21c are, for example, the entire volume according to the strength of the impeller 26a of the compressor 26 (strength against the impact in the bending direction when the ice mass is crushed) in order to limit the size of the ice mass. It is set to about 1/3 or less. Further, the interval P and the top height h of the plurality of protrusions 72p1 to 72p3 are determined in accordance with the respective set volumes of the plurality of recesses 21c within a range in which the pressure loss of the intake air can be suppressed.

  Next, the operation will be described.

  In the intake pipe structure of the internal combustion engine of the present embodiment configured as described above, moisture is condensed in the intake passage 21a upstream of the compressor 26 of the turbocharger 25 when the operation of the engine 10 is stopped. The condensed water is likely to freeze on the inner bottom wall surface portion 21b in the specific passage section 21z located on the lower side in the vertical direction. However, even if icing occurs in the specific passage section 21z, the ice is divided into a plurality of concave portions 21c by the projections 72p protruding into the intake passage 21a, and the turbocharger 25 Even if it enters the compressor 26, the size is such that it can be easily crushed. Therefore, the large ice block peeled off in the intake pipe 21 does not damage the impeller 26a of the compressor 26, which is an important part of the intake system, and does not have a complicated and expensive configuration for suppressing icing.

  In the present embodiment, since the protrusion 72p forms a protrusion extending in the passage length direction of the intake passage 21a, the protrusion 72p is formed inside the intake pipe 72 that is a part of the intake pipe 21. It can be formed easily and at low cost.

  In addition, in this embodiment, the connection pipe portion 70 which is a part of the intake pipe 21 is formed with a return hole 71s for returning the blow-by gas from the inside of the engine 10 to the intake passage 21a on the upstream side. 21z includes a range from the vicinity of the end portion 72c of the intake pipe portion 72 on the downstream side in the intake direction to the return hole position in the intake direction where the return hole 71s is formed. Even if an ice block is likely to be formed in the vicinity of the end portion 72c on the downstream side in the intake direction of the intake pipe portion 72 connected to the machine 25, the ice block is divided into a plurality of recesses 21c and damages the impeller 26a of the compressor 26. There is no.

  Further, since the protrusion 72p is constituted by a plurality of protrusions 72p1 to 72p3 which are separated from each other in the intake passage 21a and have the same height in the vertical direction (the same protrusion direction), the plurality of recesses 21c. The surface of the ice block formed on the surface can be suppressed to a uniform height in the vicinity of the height positions of the plurality of protrusions 72p1 to 72p3.

  Thus, in the intake pipe structure of the internal combustion engine of the present embodiment, even if the water in the upstream intake passage 21a freezes into the specific passage section 21z located on the lower side in the vertical direction, the ice is in the intake passage 21a. The projections 72p projecting inward are divided into a plurality of recesses 21c and formed. Therefore, such ice is of such a size that it can be easily crushed even if it enters the compressor 26 of the turbocharger 25, without using a complicated and costly configuration for suppressing freezing. An intake pipe of a low-cost internal combustion engine excellent in reliability in a low-temperature environment that can solve the problem that the ice lump formed in the intake pipe 21 easily damages important components of the intake system such as the impeller 26a of the compressor 26. Structure can be provided.

(Second Embodiment)
FIG. 4 is a side view of an essential part including a partial cross section of an intake pipe structure for an internal combustion engine according to a second embodiment of the present invention. In this embodiment, since the hot water pipe is attached to the connection pipe portion similar to the connection pipe portion 70 of the above-described embodiment, the same reference numerals are used for the same configurations as those of the first embodiment already described. It explains using.

  As shown in FIG. 4, the connection pipe portion 80 includes an intake pipe 21 that is connected to one end 58 d of the PCV hose 58 and a part of the intake pipe 21 upstream of the turbocharger 25. It is comprised by the pipe part 82 (intake pipe main body).

  The recirculation pipe portion 81 has a recirculation hole 81 s for recirculating blowby gas from the inside of the engine 10 to the intake passage 21 a on the upstream side, and a recirculation passage 58 a for recirculating blowby gas from the inside of the engine 10. And a connection portion between the intake passage 21a of the engine 10 is formed.

  A hot water pipe 83 is attached to the intake pipe portion 82 in the vicinity of the position of the reflux hole 81 s near the reflux pipe portion 81, and when a part of the cooling water of the engine 10 is passed through the hot water pipe 83. The intake pipe 82 that is a part of the intake pipe 21 upstream of the compressor 26 of the turbocharger 25 is heated in the vicinity of the reflux pipe 81.

  The intake pipe portion 82 has a protrusion 82p that protrudes into the intake passage 21a from the inner bottom wall surface portion 21b positioned on the lower side in the vertical direction in the upstream intake passage 21a, and the inner bottom wall surface portion 21b. Is partitioned into a plurality of rectangular recesses 21d in the vicinity of the protrusion 82p.

  The projecting portion 82p is composed of a plurality of wedge-shaped cross-section ridges 82p1, 82p2, 82p3, 82p4, and 82p5 extending in the passage length direction of the intake passage 21a. The ridges 82p1 to 82p5 are defined as specific passage sections. In 21z, for example, they extend parallel to each other in the passage length direction of the intake passage 21a and at different vertical heights. The plurality of rectangular recesses 21d are shallow on both sides in the inner circumferential direction of the intake passage 21a.

  In the intake structure of the internal combustion engine of the present embodiment configured as described above, water vapor generated from the PCV gas is condensed in the intake passage 21a, and the connection portion of the blow-by gas recirculation passage 58a to the intake passage 21a is connected. Even if the ice is frozen in the specific passage section 21z where the position in the vertical direction or the vertical direction is lowest, the ice is formed by being divided and divided into a plurality of recesses 21d by the protrusions 82p protruding into the intake passage 21a. In addition, ice blocks are divided and formed stepwise on both sides of the specific passage section 21z in the inner circumferential direction of the passage. Therefore, the ice is sized so that it can be easily crushed even if it enters the compressor 26 of the turbocharger 25, and has accumulated in the lowermost position in the vertical direction as in the prior art. Large ice blocks made of water do not enter the compressor 26 of the turbocharger 25. As a result, it is possible to solve the problem that the impeller of the compressor 26 is easily damaged by the ice blocks formed in the intake pipe 21 without using a complicated and expensive configuration for suppressing freezing. Can be expected.

(Third embodiment)
FIG. 5 is a front sectional view of an essential part of an intake pipe structure for an internal combustion engine according to the third embodiment of the present invention, and FIG. 6 is a sectional view taken along the line VI-VI in FIG. In addition, since this embodiment only differs in the structure of a projection part with respect to the above-mentioned 1st Embodiment, only the difference is explained in full detail.

  As shown in FIG. 5 and FIG. 6, in the present embodiment, the connection pipe part 90 includes a reflux pipe part 91 to which one end part 58 d of the PCV hose 58 is connected, and an intake air upstream from the turbocharger 25. And an intake pipe portion 92 (intake pipe main body) constituting a part of the pipe 21.

  The recirculation pipe portion 91 has a recirculation hole 91 s for recirculating blowby gas from the inside of the engine 10 to the intake passage 21 a on the upstream side, and a recirculation passage 58 a for recirculating blowby gas from the inside of the engine 10. And a connection portion between the intake passage 21a of the engine 10 is formed.

  The intake pipe portion 92 has a projection 92p that protrudes into the intake passage 21a from the inner bottom wall surface portion 21b located on the lower side in the vertical direction in the intake passage 21a on the upstream side. It is partitioned into a plurality of rectangular recesses 21e in the vicinity of the protrusion 92p.

  The protrusion 92p is composed of a plurality of wedge-shaped cross-sections (substantially triangular cross-sections) 92p1, 92p2, 92p3 extending in a direction intersecting the passage length direction of the intake passage 21a, and these protrusions 92p1 to 92p3. In the specific passage section 21z, for example, they extend in parallel to each other in a direction orthogonal to the passage length direction of the intake passage 21a. The protrusions 92p1 to 92p3 are straight in the extending direction, for example, but may be curved.

  In the present embodiment configured as described above, in addition to the same effects as those of the first embodiment described above, there are a plurality of water accumulation conditions in the intake pipe 21 upstream of the compressor 26 of the turbocharger 25. The plurality of ice blocks are difficult to be generated at the same time.

  Further, since the plurality of protrusions 92p1 to 92p3 constituting the protrusion 92p extend in a direction orthogonal to the passage length direction of the intake passage 21a, the peripheral portion of the ice block formed in the plurality of recesses 21e is It becomes thinner and more easily crushed.

  In each of the above-described embodiments, the protrusions 72p, 82p, and 92p have a substantially triangular wedge shape in cross section, but the protrusion has a semicircular cross section, a square cross section, and other polygonal shapes. It may be a cross section. In addition, the protrusion may extend not only in the intake direction or in a direction orthogonal to the intake direction, but also in a direction obliquely intersecting with the intake direction, or a plurality of intersecting ones It may be a ridge. Furthermore, the projections referred to in the present invention may be not only the ridges but also a plurality of projections arranged in the intake direction or a direction intersecting therewith, and a plurality of projections are arranged on the inner bottom of the intake pipe by the aligned projections. The concave portion may be partitioned. Further, in each of the above-described embodiments, the protrusions 72p, 82p, and 92p are formed only on the inner bottom wall surface 21b side of the intake pipe 21. However, depending on the intake pipe shape (intake flow, uneven shape, etc.) When it is easy to freeze on the inner wall surface of the pipe on the upper side in the cross section than on the inner bottom wall surface side, a protrusion may be formed in the vicinity thereof, and the protrusion on the inner wall surface of the intake pipe (for example, a plurality of protrusions) A spiral projection of the strip) may be formed, and in this case, the top height of the projection may be increased in a place where icing is likely to occur.

  Further, in each of the above-described embodiments, the turbocharger compressor is exemplified as an important part of the intake system. However, the present invention prevents a large ice block from being formed in the intake passage and damages the important parts of the intake system. Therefore, it goes without saying that the present invention can also be applied to a portion that is likely to freeze on the upstream side of other important components of the intake system other than the compressor of the turbocharger. Further, the present invention can be applied to a case where a relatively large ice block is likely to be formed in the intake passage, even when the blowby gas is not recirculated in the intake passage.

  As described above, the intake pipe structure of the internal combustion engine according to the present invention has a plurality of protrusions protruding into the intake passage even if water in the upstream intake passage freezes on the wall surface of the pipe. Because it is formed by being divided into recesses so that it does not become a large ice block, it is easy to damage important parts of the intake system due to the large ice block formed in the intake pipe without using a complicated and expensive configuration to suppress freezing It is possible to provide a low-cost intake pipe structure for an internal combustion engine that is excellent in reliability in a low-temperature environment and can solve such problems as the intake pipe structure of an internal combustion engine, particularly a turbocharger. The intake pipe structure of the internal combustion engine, which is suitable for the case where the compressor and other important components of the intake system are installed or when the blowby gas is recirculated to the intake passage upstream of the important components of the intake system. It is useful to.

It is a principal part schematic front view of the intake pipe structure of the internal combustion engine which concerns on 1st Embodiment of this invention. It is II-II arrow sectional drawing of FIG. 1 is a schematic configuration diagram of an internal combustion engine according to a first embodiment. It is a principal part schematic side view including the partial cross section of the intake pipe structure of the internal combustion engine which concerns on 2nd Embodiment of this invention. It is a principal part schematic front view of the intake pipe structure of the internal combustion engine which concerns on 3rd Embodiment of this invention. It is VI-VI arrow sectional drawing of FIG.

Explanation of symbols

10 Engine (Internal combustion engine)
14 Crankcase 15 Cylinder 21 Intake pipe 21a Intake passage 21b Inner bottom wall surface (inner wall surface)
21c, 21d, 21e Recessed parts (plural recessed parts)
21z Specific passage section 22 Exhaust pipe 25 Turbo supercharger 26 Compressor 26a Impeller 26b Inlet part 26c Inner bottom recess 58 PCV hose 58a Recirculation passage 70, 80, 90 Connecting pipe part (intake pipe body)
71, 81, 91 Reflux pipe part 71s, 81s, 91s Reflux hole 72, 82, 92 Intake pipe part (intake pipe body)
72c End 72p, 82p, 92p Projection 72p1, 72p2, 72p3 Projection (projection)
82p1, 82p2, 82p3, 82p4, 82p5 ridge (protrusion)
83 Hot water piping 92p1, 92p2, 92p3 Projection (protrusion)

Claims (8)

In an intake pipe structure of an internal combustion engine provided with an intake pipe body that forms an intake passage of the internal combustion engine,
The intake pipe main body has a protrusion protruding into the intake passage from the inner wall surface of the pipe forming the intake passage, and the inner wall surface of the pipe is partitioned into a plurality of recesses in the vicinity of the protrusion. An intake pipe structure of an internal combustion engine characterized by the above. The intake pipe body forms an intake passage on the upstream side of a compressor of a turbocharger equipped in the internal combustion engine in the intake passage, and is connected to an inlet portion of the compressor,
2. The intake pipe structure for an internal combustion engine according to claim 1, wherein the protruding portion protrudes into the intake passage from a pipe inner wall surface portion forming the upstream intake passage.   3. The intake pipe structure for an internal combustion engine according to claim 1, wherein the protrusion forms a protrusion extending in a passage length direction of the intake passage.   3. The intake pipe structure for an internal combustion engine according to claim 1, wherein the projecting portion forms a ridge extending in a direction intersecting a passage length direction of the intake passage.   The intake pipe structure for an internal combustion engine according to claim 3, wherein the protrusion extends in a direction orthogonal to a passage length direction of the intake passage.   The said protrusion part is arrange | positioned in the specific channel | path area located in the perpendicular direction lower side among the said intake pipe main bodies, The claim of any one of Claim 1 thru | or 5 characterized by the above-mentioned. Intake pipe structure of an internal combustion engine. A reflux hole is formed in the intake pipe body to recirculate blow-by gas from the inside of the internal combustion engine to the intake passage.
The specific passage section includes a range from the vicinity of an end of the intake pipe body on the downstream side in the intake direction to a position of the return hole in the intake direction where the return hole is formed. An intake pipe structure for an internal combustion engine according to any one of claims 6 to 6.   8. The projection according to claim 1, wherein the projection is constituted by a plurality of projections spaced apart from each other in the intake passage and having the same height in the vertical direction. An intake pipe structure for an internal combustion engine according to claim 1.

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