JP2008215191A - Anti-freezing structure of pcv passage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To raise the temperature of blowby gas flowing inside a metallic insertion pipe to prevent freezing of water vapor in uncombusted gas flowing in a PCV passage. <P>SOLUTION: In an anti-freezing structure of a PCV passage wherein the PCV passage for blowby gas is formed within a PCV hose, one end of the PCV hose is connected to an intake manifold made of resin, the other end is connected to a cylinder head cover, and an intake manifold side union made of resin is arranged integrally in the intake manifold, the intake manifold side union extending out in the longitudinal direction of a crankshaft is arranged on the side surface of a surge tank, extending out in the axial direction of the crankshaft, of the intake manifold extendingly arranged in the longitudinal direction of the crankshaft, a grommet is fit to the intake manifold side union, one end of an insertion pipe constituting a part of the PCV passage is inserted through the grommet, the other end of the insertion pipe is fit to the PCV hose, and a warming pipe is fixed to the outer periphery of the insertion pipe. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a freeze prevention structure for a PCV passage, and more particularly to a freeze prevention structure for a PCV passage for preventing freezing of water vapor contained in unburned gas flowing through the PCV passage.

In order to prevent the unburned gas from flowing out to the atmosphere, the engine is provided with a blow-by gas reduction device.
In this blow-by gas reduction device, unburned gas is introduced into the combustion chamber through the PCV passage that communicates the intake side of the engine and the cylinder head cover and burned again.

Japanese Patent Laying-Open No. 2005-083301

By the way, in the conventional anti-freezing structure of the PCV passage, the PCV hose forming the PCV passage is connected to an intake manifold provided in the intake manifold.
At this time, when the intake manifold is a casting, the intake manifold side union can be heated with a hot water pipe. However, in the intake manifold made of resin, since the intake manifold side union is also integrally formed with resin, the intake manifold side union Has the disadvantage that it cannot be heated with a cooling water pipe.
On the other hand, it is difficult in terms of strength to press-fit a metal cooling pipe into the resin intake manifold side union, and the metal cooling pipe thermally expands, so the metal cooling water is inserted into the resin intake manifold side union. When the pipes are brought into close contact with each other, there is a disadvantage that the resin intake manifold side union may be dissolved by the heat of the cooling pipe.
The PCV hose has a certain length because it connects the cylinder head cover of the engine and the intake manifold. However, the PCV hose may be shaken by the vibration of the engine, and the cylinder head cover or intake manifold of the engine Since various engine components are attached, there is a disadvantage that the PCV hose may interfere with the vibration when the PCV hose is shaken by engine vibration or the like.

  The object of the present invention is to increase the temperature of blow-by gas flowing through the inside of a metal insertion pipe that is inserted into a resin intake manifold at one end side and inserted into a PCV hose at the other end side, and has not yet flowed through the PCV passage. An object of the present invention is to realize a PCV passage anti-freezing structure that can prevent water vapor contained in combustion gas from freezing.

  Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a PCV passage for returning blow-by gas mainly composed of unburned gas leaking into the engine crankcase to the combustion chamber, and the PCV passage is formed in the PCV hose. One end of the PCV hose is connected to the resin intake manifold and the other end is connected to the cylinder head cover of the engine, and the resin intake manifold side union to which the PCV hose is connected is integrally provided on the intake manifold. In the anti-freezing structure of the PCV passage, a surge tank that constitutes a part of the intake manifold extends in the longitudinal direction of the crankshaft of the engine, and the crankshaft longitudinal The intake manifold side union extending in the direction is provided, and the intake manifold side union is provided with a grommet. The insertion pipe, one end of the insertion pipe constituting a part of the PCV passage is inserted into the grommet, the other end of the insertion pipe is fitted to the PCV hose, and a heating pipe is provided around the insertion pipe , And the heating pipe is connected to a water pipe that communicates the engine and the radiator, so that engine-side cooling water flows into the heating pipe.

As described above in detail, according to the present invention, a PCV passage for returning blow-by gas mainly composed of unburned gas leaking into the engine crankcase to the combustion chamber is provided, and the PCV passage is formed in the PCV hose. Freezing the PCV passage with one end of the PCV hose connected to the resin intake manifold and the other end connected to the cylinder head cover of the engine, and the resin intake manifold side union with the PCV hose connected to the intake manifold. In the prevention structure, a surge tank that constitutes a part of the intake manifold extends in the longitudinal direction of the crankshaft of the engine, and an intake manifold side union that extends in the longitudinal direction of the crankshaft extends to the side surface of the surge tank that extends in the crankshaft radial direction Fit the grommet to the intake manifold side union, and pass PCV through the grommet. One end of the insertion pipe constituting a part of the insertion pipe is inserted, the other end of the insertion pipe is fitted to the PCV hose, the heating pipe is fixed to the outer periphery of the insertion pipe, and the heating pipe communicates with the engine and the radiator The cooling water on the engine side is caused to flow into the heating pipe in communication with the water pipe.
Therefore, by inserting the insertion pipe heated by the heating pipe through the grommet fitted to the intake manifold side union, the metal insertion pipe can be connected to the resin intake manifold side union, and the inside of the insertion pipe The temperature of the blow-by gas flowing through the PCV can be raised, and the water vapor contained in the unburned gas flowing through the PCV passage can be prevented from freezing.

By inventing as described above, the grommet is fitted to the intake manifold side union, one end of the insertion pipe constituting a part of the PCV passage is inserted into the grommet, and the other end of the insertion pipe is fitted to the PCV hose to be inserted. A heating pipe is fixed to the outer periphery of the pipe, and the heating pipe is communicated with a water pipe that communicates the engine and the radiator, so that engine-side cooling water flows into the heating pipe.
As a result, the metal insertion pipe is connected to the resin intake manifold side union, the temperature of the blow-by gas flowing through the insertion pipe is raised, and the water vapor contained in the unburned gas flowing through the PCV passage is frozen. It is preventing.

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

1 to 7 show an embodiment of the present invention.
3 and 4, reference numeral 1 denotes an engine.
The engine 1 includes a cylinder block 2, a cylinder head 3 mounted on the upper part of the cylinder block 2, a cylinder head cover 4 mounted on the upper part of the cylinder head 3, and a lower part of the cylinder block 2. And an oil pan 5.
At this time, a part of the oil level gauge 6 protrudes upward from the cylinder head cover 4.

A chain cover 7 is attached to the front surface of the engine 1, and a passage boss portion extending from the vicinity of the cylinder head cover 4 to a central portion of the engine 1 below as shown in FIG. 8, an oil control valve (also referred to as “OCV”) 9 is disposed on the lower end side of the passage boss portion 8, and a mount boss portion 10 is formed on the left side portion of the passage boss portion 8 in FIG. 3. is doing.
Further, a water pump pulley 12 of a water pump 11 is disposed below the mount boss portion 10, and a crank pulley 14 attached to one end of a crankshaft 13 is disposed at the lower central portion of the engine 1. An air conditioning compressor pulley 15 is disposed on the right side of the pulley 14 in FIG. 3, and an oil filter 16 is disposed below the air conditioning compressor pulley 15. A tensioner pulley is disposed above the air conditioning compressor pulley 15.
At this time, the first belt 17 is wound around the water pump pulley 12 and the crank pulley 14, and the second belt 18 is wound around the crank pulley 14, the air conditioning compressor pulley 15, and the tensioner pulley.
That is, the rotational force of the crankshaft 13 of the engine 1 is transmitted to the water pump 11 and the air conditioning compressor via the first and second belts 17 and 18.
Further, as shown in FIG. 3, the oil control valve 9 is provided with an oil pipe 19 extending downward to an intermediate portion between the crank pulley 14 and the air conditioning compressor pulley 15 on the outer surface of the chain cover 7. The

Further, as shown in FIGS. 3 and 4, on the left side of the engine 1, a resin-made intake manifold 20 is disposed at the upper portion, and an alternator bracket 21 is disposed at the lower portion.
At this time, as shown in FIGS. 5 to 7, the resin intake manifold 20 is connected to the surge tank 22 and a plurality of, for example, four, which are connected to the surge tank 22 and each has a variable intake valve 23 disposed therein. First to fourth manifolds 24-1, 24-2, 24-3, 24-4, a cylinder head mounting flange 25 for mounting to the cylinder head 3 of the engine 1, and a back side of the engine 1 ( 4 and the throttle body mounting flange 27 of the throttle body 26 that is mounted so as to be positioned on the left side in FIG. 4 and the right side in FIG. 5 and FIG.
The throttle body mounting flange 27 is connected to the cylinder head mounting flange 25 to improve the support rigidity of the throttle body mounting flange 27.
Then, on the front side of the engine 1 of the resin intake manifold 20 (the side close to the chain cover), as shown in FIGS. 4 and 6, a variable intake valve actuator 28 for opening and closing the variable intake valve 23, A rubber-made PCV hose (also referred to as “blow-by-gas intake / reduction system hose”) 29 extending on the cylinder head cover 4 is disposed.
Further, as shown in FIG. 4, a cylinder extending from the water pump 11 on the front side of the engine 1 (right side in FIG. 4) to the rear side of the engine 1 (left side in FIG. 4) is disposed below the resin intake manifold 20. A water pump outlet pipe 30 extending in the example direction is provided.
Further, as shown in FIG. 4, the throttle body 26 is mounted on the throttle body mounting flange 27 on the back side of the engine 1 of the resin intake manifold 20 (the side away from the chain cover). A thermo case 32 connected to a water pipe 31 for warming the throttle body 26 with hot water is attached in the vicinity of 26.

Also, a PCV passage 33 is formed in the PCV hose 29 for returning blow-by gas mainly composed of unburned gas leaking into the crankcase (not shown) of the engine 1 to the combustion chamber (not shown). By connecting one end of the PCV hose 29 to the resin intake manifold 20, the other end is connected to the cylinder head cover 4 of the engine 1, and the PCV hose 29 is connected to the intake manifold 20. The union 34 is provided integrally.
At this time, the surge tank 22 constituting a part of the intake manifold 20 is extended in the longitudinal direction of the crankshaft which is the cylinder row direction of the engine 1, and the side surface of the surge tank 22 extending in the crankshaft radial direction is provided. The intake manifold side union 34 extending in the longitudinal direction of the crankshaft is provided, and a grommet 35 is fitted into the intake manifold side union 34, and one end of an insertion pipe 36 constituting a part of the PCV passage 33 is connected to the grommet 35. The other end of the insertion pipe 36 is fitted into the PCV hose 29, a heating pipe 37 is fixed to the outer periphery of the insertion pipe 36, and the heating pipe 37 is connected to the engine 1 and a radiator (not shown). ) To communicate with the water pipe 31 that communicates.
More specifically, the intake manifold side union 34 is provided on the front side of the engine 1 (the right side in FIG. 4 and the left side in FIGS. 5 and 7) as shown in FIGS. 4, 5, and 7.
At this time, as shown in FIGS. 1 and 2, the intake manifold-side union 34 has a cylindrical portion 34-1 and a large diameter formed on the intake manifold 20 side, which is one end side of the cylindrical portion 34-1. The flange portion 34-2.
Then, as shown in FIGS. 1, 2, and 7, a rubber grommet 35 is fitted to the intake manifold side union 34 and fixed with a clamp 38, and a part of the PCV passage 33 is inserted into the grommet 35. One end of the insertion pipe 36 is inserted and fixed by a clamp 38, and the other end of the insertion pipe 36 is fitted to the PCV hose 29.
Further, as shown in FIGS. 1 and 2 and FIGS. 5 to 7, a heating pipe 37 is fixed to the outer periphery of the insertion pipe 36 and the vicinity of the grommet 35, and the heating pipe 37 is connected to the engine. 1 is connected to the water pipe 31 that communicates with the radiator, and cooling water on the engine 1 side is caused to flow into the heating pipe 37.
As a result, the insertion pipe 36 heated by the heating pipe 37 is inserted into the grommet 35 fitted to the intake manifold side union 34, and the metal insertion pipe 36 is connected to the resin intake manifold side union 34. The temperature of the blow-by gas flowing through the insertion pipe 36 is improved, and the water vapor contained in the unburned gas flowing through the PCV passage 33 is prevented from freezing.

Further, as shown in FIG. 1, the grommet 35 has a through hole 35-1 through which the insertion pipe 37 is inserted into the intake manifold side union 34, and a fitting hole 35-2 to be engaged with the intake manifold side union 34. Then, the fitting hole 35-2 is formed on the outer periphery of the through hole 35-1, and one end of the insertion pipe 36 is disposed inside the intake manifold side union 34 with the clearance C maintained.
That is, in the grommet 35, as shown in FIG. 1, the grommet 35 is formed with a through hole 35-1 that penetrates the grommet 35 in the axial direction, and the grommet 35 has one end side that is the intake manifold side union 34 side. The fitting hole 35-2 is formed concentrically with the through hole 35-1 and has an inner diameter larger than that of the through hole 35-1.
The fitting hole 35-2 is formed with a bottom portion facing the end of the cylindrical portion 34-1 of the intake manifold side union 34. The cylindrical shape of the intake manifold side union 34 is formed in the fitting hole 35-2. The part 34-1 is accommodated.
The through-hole 35-1 formed on the other end side of the grommet 35 is formed when one end of the insertion pipe 36 is inserted into the inside manifold 34 through the through-hole 35-1. It is formed smaller than the inner diameter of the intake manifold side union 34 so that the clearance C can be maintained between the outer peripheral surface on one end side of the insertion pipe 36 and the inner peripheral surface of the intake manifold side union 34.
Thus, by arranging one end of the insertion pipe 36 inside the intake manifold side union 34, the resin intake manifold side union 34 is directly heated by the insertion pipe 36 heated by the heating pipe 37. The water vapor contained in the unburned gas flowing through the PCV passage 33 at the intake manifold side union 34 of the intake manifold 20 is prevented from freezing.
Even if the insertion pipe 36 is thermally expanded by blow-by gas or the like, a clearance C exists between the insertion pipe 36 and the resin-made intake manifold side union 34. There is no possibility of contact with the shaped portion 34-1 and there is no possibility that the insertion pipe 36 will dissolve the resin intake manifold side union 34.
Further, the insertion pipe 36 is kept warm by the grommet 35 to prevent the insertion pipe 36 from being directly cooled by traveling wind or the like as much as possible.

Further, a surge tank 22 constituting a part of the intake manifold 20 is extended in the crankshaft longitudinal direction of the engine 1, and the side surface of the surge tank 22 extending in the crankshaft radial direction is extended in the crankshaft longitudinal direction. As shown in FIGS. 3 and 6, the intake manifold side union 34 extending is provided, and the heating pipe 37 is extended from the engine 1 side to the surge tank 22 side so as to be bent in a dogleg shape, and this bent portion is The PCV hose 29 is joined to the periphery of the insertion pipe 36 and supported on the engine 1 side in the vicinity of the intake manifold side union 347.
As a result, the bent portion of the heating pipe 37 is joined to the insertion pipe 36, so that most of the periphery of the insertion pipe 36 is brought into contact with the heating pipe 37 and the heating pipe 37 is firmly attached to the insertion pipe 36. And the thermal conductivity from the heating pipe 37 to the insertion pipe 36 is improved, and the PCV hose 29 is supported on the engine 1 side in the vicinity of the intake manifold side union 34 to increase the support point of the PCV hose 29, The PCV hose 29 is prevented from interfering with the engine parts around the cylinder head 3 and the intake manifold 20 as much as possible.

Further, as shown in FIG. 3, an inlet side hose 40 is connected to one end of the heating pipe 37 to a head union 39 communicating with a water jacket (not shown) of the cylinder head 3. A water pump outlet pipe 30 is connected to one end in the vicinity of the water pump 11.
As a result, the high-temperature cooling water in the water jacket of the cylinder head 3 is supplied to one end of the heating pipe 37 via the head union 39 and the inlet side hose 40, and this heating pipe The temperature of the blow-by gas flowing through the insertion pipe 36 is improved by 37, and the water vapor contained in the unburned gas flowing through the PCV passage 33 is prevented from freezing.

  Next, the operation will be described.

When connecting the PCV hose 29 and the intake manifold side union 34, as shown in FIG. 2, a rubber grommet 35 is attached to the cylindrical portion 34-1 of the intake manifold side union 34 integrally formed with the intake manifold 20. And the insertion pipe 36 is inserted into the through-hole 35-1 of the grommet 35, and the outer periphery of the grommet 35 is fixed by a clamp 38. One end of the insertion pipe 36 is disposed inside the intake manifold side union 34 in a state where the clearance C is held between the inner peripheral surface of the cylindrical portion 34-1 of the intake manifold side union 34.
At this time, the heating pipe 37 in which the bent portion bent in a U-shape is joined to the periphery of the insertion pipe 36 is positioned in the vicinity of the grommet 35 as shown in FIG.
The PCV hose 29 is fitted to the other end of the insertion pipe 36 as shown in FIGS.

When the engine 1 is driven, as shown by an arrow in FIG. 1, high-temperature cooling water from the water jacket of the cylinder head 3 on the engine 1 side flows through the heating pipe 37.
At this time, the temperature of the blow-by gas flowing through the insertion pipe 36 is increased by the heating pipe 37 as indicated by the white arrow in FIG. 1, and the water vapor contained in the unburned gas flowing through the PCV passage 33 is frozen. Is prevented.

As a result, a PCV passage 33 for returning blow-by gas mainly composed of unburned gas leaking into the crankcase of the engine 1 to the combustion chamber is provided, and the PCV passage 33 is formed in the PCV hose 29. One end of the cylinder is connected to the resin intake manifold 20 and the other end is connected to the cylinder head cover 4 of the engine 1, and the resin intake manifold side union 34 to which the PCV hose 29 is connected is integrated with the intake manifold 20. In the anti-freezing structure of the PCV passage 33 provided, the surge tank 22 constituting a part of the intake manifold 20 extends in the longitudinal direction of the crankshaft of the engine 1 and extends in the crankshaft radial direction of the surge tank 22. The intake manifold side union 34 extending in the longitudinal direction of the crankshaft is provided on a side surface. A grommet 35 is fitted to the intake manifold side 34, one end of the insertion pipe 36 constituting a part of the PCV passage 33 is inserted into the grommet 35, and the other end of the insertion pipe 36 is fitted to the PCV hose 29. Then, a heating pipe 37 is fixed to the outer periphery of the insertion pipe 36, and the heating pipe 37 is communicated with a water pipe 31 that communicates the engine 1 and the radiator. Of cooling water.
Therefore, by inserting the insertion pipe 36 heated by the heating pipe 37 through the grommet 35 fitted to the intake manifold side union 34, the metal insertion pipe 36 is placed inside the resin intake manifold side union 34 (intake manifold). Since the temperature of the blow-by gas flowing inside the insertion pipe 36 can be increased, it is included in the unburned gas flowing in the PCV passage 33. It is possible to prevent the water vapor generated from freezing.

The grommet 35 is provided with a through hole 35-1 for inserting the insertion pipe 36 into the intake manifold side union 34 and a fitting hole 35-2 for fitting with the intake manifold side union 34. The fitting hole 35-2 is formed on the outer periphery, and one end of the insertion pipe 36 is disposed inside the intake manifold side union 34 with the clearance C maintained.
Accordingly, since one end of the insertion pipe 36 is disposed inside the intake manifold-side union 34, the resin-made intake manifold-side union 34 can be directly heated by the insertion pipe 36 heated by the heating pipe 37. The water vapor contained in the unburned gas flowing through the PCV passage 33 by the intake manifold side union 34 of the intake manifold 20 can be prevented from freezing.
Even if the insertion pipe 36 is thermally expanded by blow-by gas or the like, a clearance C exists between the insertion pipe 36 and the resin-made intake manifold side union 34. Therefore, the insertion pipe 36 is made of a resin-made intake manifold-side union. There is no possibility of dissolving 34.
Furthermore, the insertion pipe 36 can be kept warm by the grommet 35 to prevent the insertion pipe 36 from being cooled by traveling wind or the like as much as possible.

Further, a surge tank 22 constituting a part of the intake manifold 20 extends in the longitudinal direction of the crankshaft of the engine 1 and extends in the longitudinal direction of the crankshaft on a side surface of the surge tank 22 extending in the radial direction of the crankshaft. The intake manifold side union 34 is provided, the heating pipe 37 is extended from the engine 1 side to the surge tank 22 side and bent into a dogleg shape, and the bent portion is joined to the periphery of the insertion pipe 36. The PCV hose 29 is supported on the engine side in the vicinity of the intake manifold side union 34.
Accordingly, since the bent portion of the heating pipe 37 is joined to the insertion pipe 36, most of the periphery of the insertion pipe 36 is brought into contact with the heating pipe 37 to firmly fix the heating pipe 37 to the insertion pipe 36. In addition, the thermal conductivity from the heating pipe 37 to the insertion pipe 36 can be improved, and the PCV hose 29 is supported on the engine 1 side in the vicinity of the intake manifold side union 34 to increase the support point of the PCV hose 29. As a result, it is possible to prevent the PCV hose 29 from interfering with the engine parts around the cylinder head 3 and the intake manifold 20 as much as possible.

The present invention is not limited to the above-described embodiments, and various application modifications are possible.
For example, in the embodiment of the present invention, a PCV passage for returning blow-by gas mainly composed of unburned gas leaking into the engine crankcase to the combustion chamber is provided, and the PCV passage is formed in the PCV hose, and the intake manifold is provided. A PCV hose is connected to a resin-made intake manifold side union, and a grommet is fitted into the intake manifold side union, and one end of an insertion pipe that constitutes a part of the PCV passage is inserted into the grommet. The other end is fitted to the PCV hose, the heating pipe is fixed to the outer circumference of the insertion pipe, the heating pipe is connected to the water pipe that connects the engine and the radiator, and the engine side cooling water is connected to the inside of the heating pipe. However, the anti-freezing function should be applied to the breather introduction part to the air cleaner. Possible it is.
Then, the temperature of the breather introduction part to the air cleaner can be improved, and the water vapor flowing inside can be prevented from freezing.

It is a general | schematic cross-section perspective view of the assembly state of the insertion pipe which shows the Example of this invention. It is a perspective view which shows the assembly | attachment state of PCV hose. It is a front view of an engine. It is a left view of an engine. It is a rear view of an intake manifold. It is a right view of an intake manifold. It is sectional drawing of an intake manifold.

Explanation of symbols

1 Engine 2 Cylinder Block 3 Cylinder Head 4 Cylinder Head Cover 5 Oil Pan 7 Chain Cover 11 Water Pump 12 Water Pump Pulley 13 Crankshaft 14 Crank Pulley 15 Air Conditioning Compressor Pulley 19 Oil Pipe 20 Resin Intake Manifold 21 Alternator Bracket 22 Surge Tank 23 Variable intake valve 24-1, 24-2, 24-3, 24-4 First to fourth manifolds 25 Cylinder head mounting flange 26 Throttle body 27 Throttle body mounting flange 28 Variable intake valve actuator 29 PCV hose ("Blow-by" It is also referred to as a hose for a gas intake reduction system.)
30 Water pump outlet pipe 31 Water pipe 33 PCV passage 34 Resin intake manifold side 34-1 Cylindrical part 34-2 Flange part 35 Grommet 35-1 Through hole 35-2 Fitting hole 36 Insertion pipe 37 Heating pipe 38 Clamp C Clearance

Claims (3)

A PCV passage for returning blow-by gas mainly containing unburned gas leaking into the engine crankcase to the combustion chamber is provided, the PCV passage is formed in the PCV hose, and one end of the PCV hose is formed in a resin intake manifold. In the anti-freezing structure of the PCV passage in which the other end is connected to the cylinder head cover of the engine, and a resin-made intake manifold side union is integrally connected to the intake manifold.
The surge tank that constitutes a part of the intake manifold extends in the longitudinal direction of the crankshaft of the engine, and the intake manifold-side union extends in the longitudinal direction of the crankshaft on the side surface of the surge tank that extends in the crankshaft radial direction. A grommet is fitted to the intake manifold side union, one end of an insertion pipe constituting a part of the PCV passage is inserted through the grommet, the other end of the insertion pipe is fitted to the PCV hose, A heating pipe is fixed to the outer periphery of the insertion pipe, and the heating pipe is communicated with a water pipe that communicates the engine and the radiator so that cooling water on the engine side flows into the heating pipe. PCV passage freeze prevention structure.   The grommet is provided with a through-hole through which the insertion pipe is inserted into the intake manifold-side union and a fitting hole to be fitted into the intake manifold-side union, and the fitting hole is formed on the outer periphery of the through-hole to maintain a clearance. The PCV passage freezing prevention structure according to claim 1, wherein one end of the insertion pipe is disposed inside the intake manifold side union.   The surge tank constituting a part of the intake manifold extends in the longitudinal direction of the crankshaft of the engine, and the intake manifold side union extends in the longitudinal direction of the crankshaft on the side surface of the surge tank extending in the radial direction of the crankshaft The heating pipe is extended from the engine side to the surge tank side and bent into a square shape, and the bent portion is joined to the periphery of the insertion pipe so that the PCV hose is positioned near the intake manifold side union. The PCV passage freeze prevention structure according to claim 2, wherein the PCV passage freeze prevention structure is supported on the side.

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