JP2014105580A - Fitting structure of pcv valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fitting structure of a PCV valve, which early releases freezing of the PCV valve.SOLUTION: A fitting structure of a PCV valve includes: a resin cover 41 forming an internal space S from and to a cylinder head of an internal combustion engine; a through hole 41A for valve fitting formed in the resin cover 41; a PCV valve 30 including a valve case part 31B inserted into the through hole 41A from the outside of the resin cover 41; and a metal fixture 25 screwed into the valve case part 31B inserted into the through hole 41A from the inside of the resin cover 41, and at least partially exposed in the internal space S.

Description

  The present invention provides a cover that forms an internal space with a cylinder head of an internal combustion engine, a through hole for attaching a valve formed in the cover, and a valve case portion that is inserted into the through hole from the outside of the cover And a PCV valve mounting structure including a PCV valve (positive crankcase ventilation valve).

The PCV valve is equipped, for example, to adjust the reduction flow rate when reducing blowby gas, which is gas leaked from the combustion chamber into the crankcase during the compression / combustion stroke of the internal combustion engine, into the intake system.
However, since the PCV valve is provided outside the cylinder head and the PCV valve itself is exposed to the outside air, the moisture contained in the blow-by gas adheres to the PCV valve and freezes, especially in cold weather. May interfere with proper operation.

For this reason, for example, a PCV valve is attached to a cover that forms an internal space with the cylinder head so that frozen water can be thawed by heat generated in the internal combustion engine.
If this cover is made of a metal with high thermal conductivity, such as an aluminum alloy, the heat generated in the internal combustion engine is efficiently conducted to the PCV valve through the metal cover, and the frozen moisture is quickly transferred. Can be thawed.
However, when the cover is formed of a resin having a lower thermal conductivity than that of metal, the thawing efficiency of frozen water is deteriorated.

Patent Document 1 describes a PCV valve mounting structure capable of efficiently conducting heat generated in an internal combustion engine to a PCV valve mounted on a resin cover.
In this mounting structure, a portion of the PCV valve that is exposed to the internal space between the cylinder head and the resin cover is formed of a metal having high thermal conductivity. By heating the metal part with the heat held by the high-temperature atmosphere in the internal space, the heat transfer efficiency to the PCV valve is increased and the frozen water can be thawed.

2009-150289

However, a PCV valve formed with a metal part exposed in the internal space between the cylinder head and the resin cover is not provided with such a metal part, for example, compared to a PCV valve formed entirely with resin. Manufacturing cost increases.
Since the PCV valve is designed according to the type of the internal combustion engine, such a metal portion must be designed for each PCV valve, and there is a disadvantage in terms of manufacturing efficiency and cost when the PCV valve is equipped. It was.

  The present invention has been made in view of the above circumstances, and provides a PCV valve mounting structure that efficiently conducts heat generated in an internal combustion engine and eliminates freezing at an early stage even if it is a resin-made PCV valve. For the purpose.

  The characteristic structure of the PCV valve mounting structure according to the present invention includes a resin cover that forms an internal space with a cylinder head of an internal combustion engine, a valve mounting through-hole formed in the resin cover, and the resin. A PCV valve having a valve case portion inserted into the through-hole from the outside of the cover and a valve case portion inserted into the through-hole from the inside of the resin cover, and at least one in the internal space. And a metal fixture from which the portion is exposed.

  With the PCV valve mounting structure of this configuration, at least a part of the metal fixture screwed into the valve case portion inserted through the through hole is exposed to the internal space, and the metal fixture is attached to the internal space. It can be heated with the heat held in the high temperature atmosphere.

  Such a metal fixture is applicable to any PCV valve or valve case portion, and can be used as a common part. Therefore, the PCV valve itself can be manufactured at low cost without using metal. In addition, since the metal fixture is made common, the manufacturing unit price is reduced and inventory management is facilitated, so that the mounting structure of the PCV valve can be made more efficient.

  The characteristic configuration of the present invention includes a cylindrical screw portion in which the metal fixture is insert-molded in the resin cover, and a heat receiving portion extended from the cylindrical screw portion so as to protrude into the internal space. And the valve case portion includes a screw portion that is screwed into the cylindrical screw portion.

With this configuration, the PCV valve can be easily attached to the resin cover by an operation of screwing the screw portion included in the valve case portion into the cylindrical screw portion insert-molded in the resin cover.
Further, since the heat receiving portion protruding into the internal space is extended from the cylindrical screw portion, a large heat receiving area can be secured. For this reason, the cylindrical screw portion can be heated by receiving heat held by the high-temperature atmosphere in the internal space in a wide heat-receiving area.
Therefore, the anti-freezing effect can be further enhanced with the PCV valve mounting structure of this configuration.

It is sectional drawing of the internal combustion engine equipped with the PCV valve. It is sectional drawing which shows the attachment structure of a PCV valve | bulb. It is sectional drawing which shows the attachment structure of the PCV valve | bulb in 2nd Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
1 and 2 show a vehicle engine (internal combustion engine) E equipped with the PCV valve mounting structure of this embodiment.
As shown in FIG. 1, the engine E is connected in a form in which a cylinder head 1, a cylinder block 2, a crankcase 3, and an oil pan 4 are stacked one above the other.
A cylinder head cover 5 is provided above the cylinder head 1. The cylinder head cover 5 is made of a resin such as nylon.

  A crankshaft 6 is rotatably supported inside the crankcase 3, and pistons 7 are slidably fitted into a plurality of cylinder bores formed in the cylinder block 2. The piston 7 and the crankshaft 6 are connected by a connecting rod 8.

  The cylinder head 1 is provided with an intake valve 9 and an exhaust valve 10 that can be opened and closed, and an intake cam shaft 11 and an exhaust cam shaft 12 that are parallel to the crankshaft 6 are rotatably supported at upper positions thereof. ing.

  An intake manifold 14 is connected to one side surface of the cylinder head 1, and an exhaust manifold 15 is connected to the other side surface. A spark plug 16 for igniting the air-fuel mixture in the combustion chamber 20 is provided on the upper surface of the cylinder head 1.

  An intake passage provided in the cylinder head 1 is provided with an injector 17 for supplying fuel to the combustion chamber 20, and an intake manifold 14 is connected to the intake passage. A surge tank 18 is provided on the upstream side of the intake manifold 14, and a throttle valve 19 is connected on the upstream side of the surge tank 18.

  Although not shown, in order to rotate the intake camshaft 11 and the exhaust camshaft 12 in synchronization with the rotation of the crankshaft 6, a crank sprocket provided at the shaft end of the crankshaft 6, the intake camshaft 11 and the exhaust camshaft. An endless chain is wound around cam sprockets provided at twelve shaft ends. The spark plug 16 and the injector 17 are provided to be controlled by a control device (not shown) such as an ECU.

  With such a configuration, when the engine E is in operation, the intake cam shaft 11 and the exhaust cam shaft 12 rotate in synchronization with the rotation of the crankshaft 6 and the pressing force from the cam portion on the outer periphery of the intake cam shaft 11 The intake port of the intake valve 9 is opened at a predetermined timing. Similarly, the exhaust port of the exhaust valve 10 is opened at a predetermined timing by the pressing force from the outer cam portion of the exhaust cam shaft 12.

  The control device supplies fuel to the combustion chamber 20 by the injector 17 at a predetermined timing when the intake valve 9 is opened, and ignites the mixture by the spark plug 16 at a predetermined timing at which the air-fuel mixture in the combustion chamber 20 is compressed. Take control.

  An oil supply pipe 21 is disposed in the cylinder head cover 5 above the intake cam shaft 11 and the exhaust cam shaft 12 in a posture parallel to the cam shafts 11 and 12. The oil supply pipe 21 is provided with a spray nozzle 21A for spraying oil downward.

Thereby, when the engine E operates, the oil supplied to each of the oil supply pipes 21 by the hydraulic pump (not shown) is sprayed from the spray nozzle 21A to the intake camshaft 11 and the exhaust camshaft 12.
Although not shown, the cylinder head 1 is formed with a discharge port for discharging oil, and an oil passage for returning the oil discharged from the discharge port to the oil pan 4 is formed.

When the engine E is in operation, a part of the mixed gas introduced into the combustion chamber 20 leaks into the crank chamber 13 through a gap between the outer periphery of the piston 7 and the inner periphery of the cylinder. The unburned mixed gas leaked in this way is called blow-by gas.
The engine E includes a blow-by gas reduction device that reduces the blow-by gas to the intake system of the engine E, introduces it into the combustion chamber 20 together with a new mixed gas, and burns it.

The blow-by gas reduction device supplies the blow-by gas generated in the crank chamber 13 to the oil separator 40 mounted on the upper part of the cylinder head cover 5 through the gas extraction path 22 and transfers the blow-by gas from which the oil mist has been separated to the gas space S. And store.
The blow-by gas stored in the gas space S is sent to the gas reduction path 23 through the PCV valve 30, is reduced to the intake system (specifically, the surge tank 18) of the engine E, and is burned in the combustion chamber 20 together with the air-fuel mixture.

  As shown in FIG. 2, the oil separator 40 is fixed to the upper surface of the cylinder head cover 5 with the gasket 24 interposed therebetween, and includes a cyclone type separation unit 43 that separates and removes oil mist contained in blow-by gas.

The oil separator 40 integrally includes an upper case portion 41 that forms a gas space (internal space) S and a lower case portion 42 that includes a separation unit 43 therein. A partition wall 44 is formed at an intermediate portion of the partition wall, and a supply space T is formed on the outer peripheral side of the separation unit 43 below the partition wall 44.
Each of the upper case 41, the lower case 42, the separation unit 43, and the partition wall 44 is formed of a resin material such as nylon similarly to the cylinder head cover 5.

  In the separation unit 43, a funnel-shaped portion 43B is integrally formed below the cylindrical portion 43A, and an opening 43H communicating with the supply space T is formed on the outer periphery of the cylindrical portion 43A, and communicates with the inside of the cylinder head cover 5. A hole 43C is formed at the lower end of the funnel-shaped portion 43B. A through hole 44 </ b> A is formed in the partition wall 44 at the upper position of the cylindrical portion 43 </ b> A of the separation unit 43.

With this configuration, when blow-by gas is supplied to the supply space T, a gas containing oil mist is introduced from the opening 43H into the cylindrical portion 43A of the separation unit 43 in the tangential direction, and the gas is introduced by this introduction. Turns.
The oil mist is agglomerated and separated by the action of the centrifugal force generated by the swirling of the gas, and the agglomerated oil is sent from the inner surface of the funnel-like part 43B to the hole part 43C, and is sent out into the cylinder head cover 5 through the hole part 43C. Further, the blow-by gas from which the oil mist has been removed is guided to the gas space S from the through hole 44 </ b> A of the partition wall 44.

The PCV valve 30 is attached to the upper case portion 41 so as to communicate with the gas space (internal space) S of the upper case portion 41.
Accordingly, the upper case portion 41 corresponds to a resin cover that forms an internal space (gas space S) with the cylinder head cover 5 between the upper case portion 41 and the cylinder head 1 of the engine E, and a through hole 41A for attaching the valve is formed sideways. It is.

  The PCV valve 30 includes a valve body 31, a valve body 32 housed inside the valve body 31, a support member 33 that prevents the valve body 32 from falling off the valve body 31, and a valve body 32 in a closing direction. The supporting member 33 is formed with a hole 33A.

The valve main body 31 includes a connecting cylinder portion 31A connected to the gas reduction path 23, a cylindrical main body portion 31B forming a housing portion for the valve body 32, and an annular flange portion 31C having a hexagonal shape and a different diameter, for example. Are integrally formed, and a male screw portion 31D is formed on the outer peripheral portion of the cylindrical main body portion 31B.
Although the valve main body 31, the valve body 32, the support member 33, and the spring 34 are assumed to be made of a resin material, all or part of them may be made of a metal material.

The cylindrical main body portion 31B corresponds to a valve case portion that is inserted from the outside of the upper case portion 41 into the valve mounting through hole 41A, and the insertion depth is reduced by the contact between the annular flange portion 31C and the upper case portion 41. The through hole 41A is inserted in a regulated state.
The PCV valve 30 is fixed to the upper case portion 41 by screwing a metal fixture 25 into the male screw portion 31D of the cylindrical main body portion 31B inserted through the through hole 41A from the inside of the upper case portion 41.

The metal fixture 25 includes a cylindrical screw portion 26 formed with a female screw portion 26A that is screwed into the male screw portion 31D of the cylindrical main body portion 31B.
The metal fixture 25 is insert-molded in a non-rotating state in the upper case portion 41 so that a part of the cylindrical screw portion 26 is exposed to the gas space S, and the whole is made of, for example, an aluminum alloy or a copper alloy. It is made of a metal with high thermal conductivity.

  A part of the cylindrical screw portion 26 including a portion not embedded in the upper case portion 41 and a female screw portion where the male screw portion 31D is not screwed is exposed to the gas space S, so that the gas space S The metal fixture 25 is configured to be heated with heat held by a high-temperature atmosphere containing blow-by gas.

  Such a metal fixture 25 can be applied to any PCV valve 30 or cylindrical body portion (valve case portion) 31B, and can be used as a common component. Therefore, the PCV valve 30 itself can be manufactured at low cost without using metal. Further, since the metal fixture 25 is also used in common, the manufacturing unit price is reduced and inventory management is facilitated, so that the mounting structure of the PCV valve 30 can be made more efficient.

The valve body 31 is fixed to the upper case portion 41 with the annular flange portion 31C and the cylindrical screw portion 26 sandwiching the periphery of the through hole 41A of the upper case portion 41.
Accordingly, the portion 41B sandwiched between the annular flange 31C and the cylindrical screw portion 26 in the upper case portion 41 serves as an annular sealing material that seals the gap between the fixing cylindrical portion 31B and the through hole 41A. It is functioning.

[Second Embodiment]
FIG. 3 shows a second embodiment of the present invention.
In this embodiment, the metal fixture 25 has a cylindrical screw portion 26 that is insert-molded in the upper case portion 41 so that a part of the metal fixture 25 is exposed to the gas space S, and a downward direction along the cylinder radial direction in the gas space S. Are integrally provided with a plate-shaped heat receiving portion 27 extending from the cylindrical screw portion 26 so as to protrude from the cylindrical screw portion 26.

The heat receiving portion 27 is preferably formed in a shape that does not hinder the flow of blow-by gas in the gas space S. The heat receiving portion 27 may be provided as a flow path forming member that forms a flow path for blow-by gas in the gas space S.
Other configurations are the same as those of the first embodiment.

[Other Embodiments]
1. In the PCV valve mounting structure according to the present invention, the entire metal fixture screwed into the valve case portion from the inside of the resin cover may be exposed in the internal space of the resin cover.
2. The mounting structure of the PCV valve according to the present invention is a metal made by inserting a valve case portion into a valve mounting through-hole formed in a resin cylinder head cover and screwing into the valve case portion from the inside of the cylinder head cover. At least a part of the fixture may be exposed in the internal space of the cylinder head cover.
3. The mounting structure of the PCV valve according to the present invention can be applied to various internal combustion engines equipped with the PCV valve.

DESCRIPTION OF SYMBOLS 1 Cylinder head 25 Metal fixture 26 Cylindrical screw part 27 Heat receiving part 30 PCV valve 31B Valve case part 31D Screw part 41 Upper case part (resin cover)
41A Through-hole E for valve mounting Internal combustion engine S Gas space (internal space)

Claims (2)

A resin cover that forms an internal space with the cylinder head of the internal combustion engine;
A through hole for attaching a valve formed in the resin cover;
A PCV valve having a valve case portion inserted into the through hole from the outside of the resin cover;
A metal fixture that is screwed into the valve case portion inserted through the through-hole from the inside of the resin cover and at least a part of which is exposed in the internal space;
The mounting structure of the PCV valve provided with The metal fixture integrally includes a cylindrical screw portion that is insert-molded in the resin cover, and a heat receiving portion that extends from the cylindrical screw portion so as to protrude into the internal space,
The PCV valve mounting structure according to claim 1, wherein the valve case portion includes a screw portion that is screwed into the cylindrical screw portion.

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