JP2020097918A - Blow-by gas recirculation device - Google Patents

Abstract

To provide a blow-by gas recirculation device improved so that a PCV valve can be mounted on a cylinder head cover even in an engine of cold-district specification, to have a state where the PCV valve can be properly operated without frozen by cold, even when it is mounted on the cylinder head cover in a state of being exposed to the external.SOLUTION: In a blow-by gas recirculation device constituted to return a blow-by gas g in a crank case to an intake passage by using an internal gas passage w of a head cover 3, a PCV valve B acting on the cover internal gas passage w is disposed on the head cover 3 in a state of using a top wall 3a of the head cover 3, a temperature rising mechanism C capable of heating the PCV valve B is disposed on the head cover 3, and the temperature rising mechanism C is constituted by forming a flow channel 44 in which a fluid r flows, in the vicinity of the PCV valve B in the head cover 3.SELECTED DRAWING: Figure 6

Description

The present invention relates to a blow-by gas recirculation device equipped in an industrial engine, a running vehicle engine, or the like.

The blow-by gas recirculation system is a mechanism that allows blow-by gas that collects in the crankcase to flow back to the intake passages of the intake manifold and air cleaner, mix with a new air-fuel mixture, burn, and not release to the atmosphere as it is, that is, a blow-by gas recirculation device to the engine. It is provided. In an engine with a blow-by gas recirculation device, it is desirable to remove liquid components such as oil (oil mist) and water contained in blow-by gas as much as possible before returning to the intake passage.

Therefore, conventionally, a configuration is often adopted in which the liquid component is returned from the crankcase to the intake passage through the cylinder head and the cylinder head cover so that the liquid component is easily captured inside the engine. As such examples, those disclosed in Patent Document 1 and Patent Document 2 are known.

JP, 2008-163837, A JP, 2003-184531, A

Since blow-by gas contains water, it may be disadvantageous for the blow-by gas recirculation device in a cold season such as winter when the water may freeze. For example, a configuration in which a PCV valve that regulates the pressure between the inside of the engine and the intake passage is arranged above the cylinder head cover in a state in which a part of the PCV valve is provided outside the cylinder head cover, that is, in the externally exposed state (Patent Document 1) 1 and FIGS. 3 and 4 of Patent Document 2). In cryogenic conditions, the components of the valve such as the diaphragm may freeze and may not operate. Therefore, there is a disadvantage that the PCV valve in the externally exposed state cannot be provided in the cold region specifications.

An object of the present invention is to improve the structure of a cylinder head cover by a structure so that even if a PCV valve is provided on the cylinder head cover in an externally exposed state, the PCV valve does not freeze due to the cold and the cylinder head cover has an externally exposed state. It is an object of the present invention to provide an improved blow-by gas recirculation device capable of installing the PCV valve of the above.

The present invention provides a blow-by gas recirculation device configured to return blow-by gas in a crankcase to an intake passage using an internal gas passage of a cylinder head cover,
The PCV valve acting on the gas passage in the cover is configured in the cylinder head cover in a state of using the outer wall of the cylinder head cover,
A temperature raising mechanism capable of warming the PCV valve is provided in the cylinder head cover,
The temperature raising mechanism is configured by forming a flow path through which a fluid flows in a position near the PCV valve in the cylinder head cover.

For example, a PCV valve is a diaphragm valve, which is arranged at a gas outlet portion of a gas passage in a cover with respect to a cylinder head cover, and a cover lid which allows the diaphragm to be attached and detached is detachably attached to the cylinder head cover.

The fluid flow passage has a lateral deep hole extending toward the PCV valve arranged using the top wall of the cylinder head cover, formed in the top wall of the cylinder head cover, and reaching the hole bottom portion of the lateral deep hole. It would be convenient if there was an inlet pipe.

Further, it is preferable that a lid having a fluid outlet for the deep hole and capable of closing the opening of the deep hole while supporting the inlet pipe is attached to the cylinder head cover. Further, it is convenient that the lid is provided with an air bleeding portion for the fluid, and it is preferable to use cooling water as the fluid.

According to the present invention, the PCV valve can be warmed by the temperature raising mechanism even in a situation where the PCV valve exposed to the outside in an extremely cold state is cooled, so that water in the blow-by gas is frozen in the PCV valve. And the valve can operate well.
Since the temperature raising mechanism is formed by forming a flow path for flowing the fluid in the vicinity of the PCV valve in the cylinder head cover, the temperature raising mechanism is provided in the cylinder head cover itself in a space-saving manner without attaching a dedicated device. be able to.

As a result, the PCV valve provided on the cylinder head cover in an externally exposed state works well without freezing in the cold by equipping the cylinder head cover with the PCV valve on the cylinder head cover even if the engine is designed for cold regions. It is possible to provide an improved blow-by gas recirculation device that can be installed.

It should be noted that the PCV valve is a diaphragm valve that is provided on the top of the cylinder head cover and has a lid made of sheet metal, and when cooling water is used as a fluid to flow to the cylinder head cover itself, it is weak in cold and freezes. The easy-to-use diaphragm valve can be reasonably warmed by using the existing engine cooling system, and it has the advantage that it can be easily adopted even in cold climate specifications.

Front view of industrial diesel engine Plan view of the engine shown in FIG. Left side view of the engine shown in FIG. (A) A perspective view of the main part of the upper part of the engine shown in FIG. 1 seen from the upper left front, and (B) a perspective view showing a supply/discharge part of cooling water to/from a cylinder head cover. Plan view of cylinder head cover, etc. The heating mechanism is shown, (A) is a plan view of the main part, (B) is a right side view of the main part Cross-sectional view of the main part showing the heating mechanism

Hereinafter, an embodiment of a blow-by gas recirculation system according to the present invention will be described with reference to the drawings when applied to an industrial diesel engine.

As shown in FIGS. 1 to 4, an industrial diesel engine (hereinafter simply referred to as an engine) E has a cylinder head 2 mounted on a cylinder block 1 and a cylinder head cover ( Hereinafter, abbreviated as “head cover” 3 is assembled, and an oil pan 4 is assembled under the cylinder block 1.
A transmission case 5 is assembled to the front end of the cylinder block 1, an engine cooling fan 6 is arranged at the front of the transmission case 5, and a flywheel housing 7 is arranged at the rear of the cylinder block 1. The upper half of the cylinder block 1 is formed in the cylinder 1A, and the lower half is formed in the crankcase 1B.

At the front of the engine E, a drive belt 8 mounted on a shaft end of a crankshaft (not shown), a drive fan pulley 6A of the engine cooling fan 6, and a passive pulley 9A of a dynamo (alternator) 9, It is equipped with a water flange 30 and the like. An exhaust manifold 11, a supercharger 12, a starter 13, an EGR cooler 14 and the like are provided on the left side of the engine E. An intake manifold 15, an oil filter 17, etc. are provided on the right side of the engine E. A compressor downstream suction passage (secondary air passage) 18 (see FIG. 2) is arranged above the engine E.

An exhaust gas treatment device 19 is provided at an upper portion and a rear portion of the engine E. The exhaust gas treatment device 19 is an exhaust gas primary treatment device (DPF or the like) 19A arranged at the upper part of the flywheel housing 7 at the rear part of the engine E, and an exhaust gas secondary treatment process arranged at the upper part of the engine E near the rear part of the head cover 3. It has a device (SCR, DOC, etc.) 19B. These exhaust gas treatment devices 19 are supported by a mounting frame 16 that is bolted to the cylinder block 1.

The intake passage a is a general term having the compressor upstream suction passage 20, the compressor downstream suction passage 18, and the intake manifold 15. The compressor upstream suction passage 20 is an intake passage a formed by a pipe connecting an air cleaner (not shown) and a compressor housing 12A of the supercharger (turbocharger) 12. The compressor downstream side intake passage 18 is an intake passage a formed by a pipe connecting the compressor housing 12A and the intake manifold 15.

As shown in FIGS. 1 to 3 and FIG. 4A, the engine E has a blow-by gas in the crankcase 1B and a blow-by gas including an in-cover gas passage 3A in the head cover 3 (see FIG. 5). A blow-by gas recirculation device A for returning to the intake passage a using the gas passage w is provided. The blow-by gas passage w has a gas duct 21 that connects the upper left side of the head cover 3 and the compressor upstream suction passage 20. The gas duct 21 is configured as a curved pipe path that connects a blow-by gas outlet (not shown) of the head cover 3 and the straight pipe 23.

As shown in FIG. 1 to FIG. 3 and FIG. 4(A), the compressor upstream suction passage 20 has a connecting pipe 29 externally fitted to an inlet pipe (not shown) of the compressor housing 12A, and a connecting pipe. A straight pipe 23 that is internally fitted and connected to the pipe 29, and an air passage pipe (not shown) that connects the straight pipe 23 and an air cleaner (not shown). In the straight pipe 23, a rush pipe (not shown) serving as a terminal end of the blow-by gas passage w is formed in a laterally branched shape, and the rush pipe portion of the straight pipe 23 can be heated by using cooling water r. The mechanism 22 is integrally provided.

Next, the configuration of the head cover 3 portion in the blow-by gas recirculation device A will be described. As shown in FIGS. 4 to 6, a PCV (Positive Crankcase Ventilation) valve B that acts on the gas passage 3A in the cover is configured in the head cover 3 in a state where a top wall (an example of an outer wall) 3a of the head cover 3 is used. .. As shown in FIG. 4(B), the PCV valve B is a diaphragm valve, and a cover lid 41 made of a sheet metal material that enables assembly and removal of the diaphragm 40 is fixed to the top wall 3a of the head cover 3 with a screw or the like. It is detachably attached. By providing the PCV valve B on the head cover 3 in an externally exposed state, there is an advantage that maintenance of the inside of the valve (replacement of the diaphragm 40, etc.) can be performed by attaching and detaching the lid 41 without removing the head cover 3.

In the blow-by gas passage w of the blow-by gas recirculation device A, the head cover 3 is provided with a PCV valve B (sometimes referred to as a breather valve) having a diaphragm valve structure. This is a well-known technique in Japanese Unexamined Patent Application Publication No. 2006-22650) or Patent Document 4 (JP 2004-116395A), and the structure of the PCV valve B and the internal structure of the head cover 3 will be described here only briefly.

The PCV valve B is provided in the top wall 3a using a valve installation hole 42 formed in the top wall 3a, and the blow-by gas that has passed through the in-cover gas passage 3A and the PCV valve B faces left front. The gas exits 43 formed in the lower part of the valve installation hole 42 flow out to the gas duct 21. That is, the PCV valve B is arranged at the gas outlet portion 43 in a state where most of its constituent elements are formed on the top wall 3a itself. 6A and 7, 51 is an annular valve seat, 52 is a peripheral space communicating with the in-cover gas passage 3A, 53 is a discharge passage, and 53a is a discharge passage inlet. A plurality of nut portions 3c for bolting the cover lid 41 to the top wall 3a are formed near the periphery of the valve installation hole 42.

As shown in FIGS. 4 to 7, the head cover 3 is provided with a temperature raising mechanism C capable of warming the PCV valve B. The temperature raising mechanism C is configured by forming a flow path 44 through which cooling water (an example of a fluid) r flows in a location near the PCV valve B on the top wall 3a of the head cover 3. The flow path 44 is formed in the thickness of the top wall 3a with a deep hole (horizontal hole) that opens to the right side and extends laterally leftward toward the PCV valve B. The deep hole 44 includes a vertical hole portion 44A extending laterally (leftward), a shallow hole portion 44B extending forward from the vertical hole portion 44A, and an opening portion 44C that is long in the front and rear direction, and is L in plan view (see FIG. 7). It is formed in a lateral hole having a V shape.

As shown in FIG. 4(B), FIG. 6 and FIG. 7, a lid 45 capable of closing the opening 44C of the flow path 44 is detachably attached to the head cover 3 with two bolts 46, 46. There is. The lid body 45 is configured by integrally mounting the inlet pipe 47 and the outlet pipe 48 to the lid main body portion 45A, and using the two attachment holes 45a, 45a of the lid main body portion 45A that are long in the front and rear, the top wall 3a. It is mounted in a liquid-tight manner on a vertical mounting surface 3b formed on the right side of. A gasket (not shown) may be provided between the mounting surface 3b and the lid 45, if necessary.

The inlet pipe 47 is liquid-tightly supported by the rear portion of the lid main body 45A, and its front end 47a is provided with a large insertion amount so as to reach the hole bottom 44a of the vertical hole 44A. The outlet pipe 48 is an outlet for fluid to the deep hole, and is fitted and fitted in a liquid-tight manner in an outlet protruding portion 45B formed in the front portion of the lid main body portion 45A. On the inner side surface of the lid main body portion 45A, a discharge introduction recess 49 located at the outlet protrusion 45B and a flat recess 50 which is long in the front and rear and has an extremely shallow depth are continuously formed. When the lid 45 is assembled to the head cover 3, the discharge introduction recess 49, the flat recess 50, and the opening 44C are configured to face each other with substantially the same size.

In the temperature raising mechanism C, the cooling water r enters the hole bottom 44a of the vertical hole portion 44A from the inlet pipe 47, and then flows into the vertical hole portion 44A, the shallow hole portion 44B, the discharge introduction recess 49, and the outlet pipe 48. When flowing through the flow path 44, the heat of the cooling water r is conducted to the valve structure portion 58 and the peripheral portion 59 of the PCV valve B in the head cover 3, so that the temperature of the PCV valve B can be raised quickly and efficiently. A supply pipe 54 for the cooling water r is connected to the inlet pipe 47, and a discharge pipe 55 is connected to the outlet pipe 48 [see FIG. 4(B)].

Even when the PCV valve B with the lid 45 exposed to the outside may freeze due to the temperature raising mechanism C during extremely cold weather such as winter, the temperature of the cooling water r is rapidly increased with engine start, and the cooling water r becomes warm fluid. The PCV valve B can be heated from the inside by the cooling water r. Therefore, the water in the blow-by gas is prevented from freezing in the PCV valve B, and the blow-by gas recirculation device A in which the PCV valve B operates well can be realized. Further, since the flow passage 44 is formed in the head cover 3 itself, it is not necessary to provide another dedicated flow passage, and the temperature raising mechanism C is economical and space-saving, while the PCV valve B is provided at its central portion. It is possible to quickly and efficiently raise the temperature from a certain valve structure portion 58.

As shown in FIGS. 4(B), 6(A), and 6(B), a base portion 56 for an air bleeding portion (air bleeding) D that acts on the blow-by gas passage w is formed in the lid 45. The air bleeding section D includes a base section 56 and a bleeding operation tool 57 attached to the base section 56. The base portion 56 is formed on the outlet protrusion 45B with a vertical hole 56a communicating with the discharge introduction recess 49. The extraction operation tool 57 shown in FIG. 6(B) (not shown in FIG. 4(B)) is composed of, for example, a screw plug or a union bolt, but is not limited thereto.

Since the PCV valve B and the lid 45 are at the highest position in the blow-by gas passage w, there is a merit that the air can be bleeded as the blow-by gas passage w by one air bleeding portion D provided in the lid 45. .. The lid 45 has a rational structure that serves both as a component of the temperature raising mechanism C and as a main part (base 56) of the air bleeding section D, which reduces cost, makes it compact, or simplifies the configuration. It is convenient in terms of.

As shown in FIGS. 1 to 3, there is provided a heating mechanism 22 capable of heating the recirculation passage portion k in which the blow-by gas passage w is connected to the intake passage a. The recirculation passage portion k is configured as a portion where the rush pipe 28, which is the terminal end portion of the blow-by gas passage w, and the straight pipe 23 (the intake passage a) are obliquely connected to each other.

The heating mechanism 22 has a pipe line 24 for passing the cooling water r attached to the reflux passage part k, and a cooling water inlet part (not shown) made of a metal pipe is provided below the pipe line 24 made of a metal pipe. The cooling water outlets 26 made of metal pipes are liquid-tightly provided on the upper side. The conduit 24 is attached by welding (welding or the like) across both the straight pipe 23 and the plunge pipe 28.

A first connecting tube 34 connecting a branched pipe (not shown) from the EGR cooler cooling water pipe 32 and a cooling water inlet (not shown), and a second connecting tube connecting the water pump 31 and the cooling water outlet 26. And 33 are provided. The cooling water r enters, for example, a pipe 24 from a cooling water inlet (not shown) on the lower side, is thermally conducted to the reflux passage k when passing through the pipe 24, and then the cooling water outlet on the upper side. Go out from 26.

In extremely cold weather, the water in the blow-by gas that has been recirculated to the rush pipe 28 or the straight pipe 23 is cooled by the low-temperature fresh air and freezes, and the freezing narrows or blocks the internal passage of the rush pipe 28. The advantage that the inconvenience that occurs does not occur is obtained. The straight pipe 23, the rush pipe 28, and the pipe line 24 are metal pipes, and the recirculation passage portion k has excellent thermal conductivity, and the heat of the cooling water r can warm the blow-by gas g and cold fresh air.

[Another embodiment]
(1) In addition to the deep holes, the flow path 44 in the temperature raising mechanism C may have a structure in which a pipe path is formed in the head cover 3 itself or a structure in which a separate pipe is cast into the wall thickness of the head cover 3 to be formed. Good. In addition, the flow path 44 may be provided so as to surround the valve installation hole 42 so that the PCV valve can be heated more efficiently.
(2) The PCV valve B provided on the head cover 3 may be a valve having a structure other than the diaphragm valve. As the outer wall 3a of the head cover 3, front and rear or left and right side walls are desired, and in that case, it is desirable to arrange the PCV valve at the top portion of the side wall.
(3) The fluid r used in the temperature raising mechanism C may be a fluid other than cooling water, such as engine oil or exhaust gas, and these heated and warm or hot fluids may be collectively referred to as “warm fluid”. ..

1B Crankcase 3 Cylinder head cover 3A Cover gas passage 3a Outer wall (top wall)
40 diaphragm 41 cover lid 43 gas outlet 44 flow path (deep hole)
44C Opening 44a Hole bottom 45 Lid 47 Inlet pipe 48 Outlet B PCV valve C Temperature raising mechanism D Air bleeding portion a Intake passage r Fluid (cooling water)
w Blow-by gas passage

Claims (8)

A blow-by gas recirculation device configured to return blow-by gas in a crankcase to an intake passage using an internal gas passage of a cylinder head cover,
The PCV valve acting on the gas passage in the cover is configured in the cylinder head cover in a state of using the outer wall of the cylinder head cover,
A heating mechanism capable of heating the PCV valve is provided in the cylinder head cover,
The blow-by gas recirculation device, wherein the heating mechanism is configured by forming a flow path for flowing a fluid in a location near the PCV valve in the cylinder head cover. The blow-by gas recirculation device according to claim 1, wherein the PCV valve is arranged at a gas outlet portion of the gas passage in the cover with respect to the cylinder head cover. The blow-by gas recirculation device according to claim 1 or 2, wherein the PCV valve is a diaphragm valve, and a cover lid that allows assembly and removal of the diaphragm is detachably attached to the cylinder head cover. The flow passage is formed such that a deep hole extending toward the PCV valve is formed in an outer wall of the cylinder head cover, and a fluid inlet pipe for the flow passage reaches a hole bottom portion of the deep hole. The blow-by gas recirculation device according to any one of 1 to 3. The blow-by gas according to claim 4, wherein the PCV valve is configured by using a top wall of a cylinder head cover, and the deep hole is formed in a lateral hole that extends laterally within a thickness of the top wall in a state of laterally opening. Reflux device. The lid body having an outlet for fluid to the deep hole and capable of closing the opening of the deep hole while supporting the inlet pipe is attached to the cylinder head cover. Blow-by gas recirculation device. The blow-by gas recirculation device according to claim 6, wherein the lid body is provided with an air bleeding portion for the fluid. The blow-by gas recirculation device according to any one of claims 1 to 7, wherein cooling water is used as the fluid.

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