JP2021156198A - Blow-by gas recirculation device - Google Patents

Abstract

To provide a blow-by gas recirculation device that can suppress freezing of condensed water even in a low-atmospheric temperature environment.SOLUTION: A blow-by gas recirculation device 100 includes: an introduction port 20 for introducing a blow-by gas into an intake inlet part 13 of a compressor 10 of a turbocharger 5; and an adjacent passage 30 provided upstream in a blow-by gas flow direction as compared to the introduction port 20 and adjacent to a scroll part 14 of the compressor 10.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a blow-by gas recirculation device.

In an internal combustion engine, a blow-by gas recirculation device that recirculates blow-by gas leaking into a crankcase from a gap between a piston and a cylinder to an intake passage is known. Further, a turbocharged internal combustion engine in which a turbocharger compressor is provided in an intake passage is also known.

Generally, the blow-by gas recirculation device includes an inlet for introducing blow-by gas at the intake inlet of the compressor.

JP-A-2007-309257

However, in the above blow-by gas recirculation device, the temperature of the blow-by gas is lowered by cooling the introduction port by the outside air, and condensed water may be generated inside the introduction port and the intake passage in the vicinity thereof.

In addition, in an environment where the atmospheric temperature is low, condensed water may freeze inside these. As a result, the frozen ice may flow downstream, damaging the compressor.

Therefore, the present disclosure was devised in view of such circumstances, and an object of the present disclosure is to provide a blow-by gas recirculation device capable of suppressing freezing of condensed water even in an environment where the atmospheric temperature is low.

According to one aspect of the present disclosure, it is a blow-by gas recirculation device for an internal combustion engine, wherein the internal combustion engine includes an intake passage and a compressor of a turbocharger provided in the intake passage. A compressor impeller and a housing for rotatably accommodating the compressor impeller are provided, and the housing includes an intake inlet portion located upstream of the compressor impeller and downstream of the compressor impeller in the intake flow direction. The blow-by gas recirculation device is arranged on the side and has a scroll portion extending in the circumferential direction at a position on the outer peripheral side of the compressor impeller, and the blow-by gas recirculation device is the intake inlet portion or the intake portion on the upstream side of the intake inlet portion. Provided is a blow-by gas recirculation device including an introduction port for introducing blow-by gas into the passage and an adjacent passage provided on the upstream side of the introduction port in the flow direction of the blow-by gas and adjacent to the scroll portion. NS.

Preferably, the adjacent passage extends circumferentially along the scroll portion.

Further, the adjacent passage has a gas inlet for introducing blow-by gas, a gas outlet for discharging blow-by gas, and a partition wall for partitioning the gas inlet and the gas outlet, and the circumference from the gas inlet to the gas outlet. Extend in the direction.

According to the present disclosure, it is possible to suppress freezing of condensed water even in an environment where the atmospheric temperature is low.

It is a schematic top view which shows the whole structure of the internal combustion engine including a blow-by gas recirculation device. It is an enlarged sectional view of the blow-by gas recirculation apparatus, and is the sectional view of line II-II shown in FIG. It is sectional drawing of the line III-III shown in FIG.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

First, the overall configuration of the internal combustion engine 1 in the present embodiment, particularly the compressor 10 of the turbocharger 5 will be described. In the figure, the white arrow A indicates the flow of intake air, and the black arrow G indicates the flow of exhaust gas. Further, the directions of up, down, front, back, left, and right shown in the figure are merely defined for convenience of explanation, but coincide with each direction of the vehicle (not shown) equipped with the internal combustion engine 1.

As shown in FIG. 1, the internal combustion engine 1 is a multi-cylinder compression ignition type internal combustion engine mounted on a vehicle, for example, a 4-cylinder diesel engine. The vehicle is a large vehicle such as a truck. However, the type, type, application, etc. of the vehicle and the internal combustion engine 1 are not particularly limited. For example, the vehicle may be a small vehicle such as a passenger car, and the internal combustion engine 1 is a spark ignition type internal combustion engine such as a gasoline engine. It may be. Further, the internal combustion engine 1 may be mounted on a moving body other than a vehicle, for example, a ship, a construction machine, or an industrial machine. Further, the internal combustion engine 1 does not have to be mounted on a moving body, and may be a stationary type.

The internal combustion engine 1 includes an engine main body 2, an intake passage 3, an exhaust passage 4, and a turbocharger 5.

The engine body 2 includes structural parts (not shown) such as a cylinder head, a cylinder block, and a crankcase, and movable parts (not shown) such as a piston, a crankshaft, and a valve operating mechanism housed therein. A head cover 2a that covers the valve operating mechanism is connected to the upper part of the cylinder head.

The intake passage 3 includes an intake manifold 3a connected to the engine body 2 (particularly, a cylinder head) and an intake pipe 3b connected to the upstream end of the intake manifold 3a.

The intake manifold 3a distributes and supplies the intake air sent from the intake pipe 3b to the intake ports of each cylinder. The intake pipe 3b is provided with an air cleaner 3c, a turbocharger 5 compressor 10, and an intercooler 3d in this order from the upstream side.

The exhaust passage 4 includes an exhaust manifold 4a connected to the engine body 2 (particularly, a cylinder head) and an exhaust pipe 4b arranged on the downstream side of the exhaust manifold 4a.

The exhaust manifold 4a collects the exhaust gas sent from the exhaust port of each cylinder. A turbine 5T of a turbocharger 5 is provided between the exhaust manifold 4a and the exhaust pipe 4b.

The turbine 5T includes a turbine rotor 5a that is rotationally driven by exhaust gas, and a turbine housing 5b that rotatably accommodates the turbine rotor 5a.

The compressor 10 is a centrifugal compressor and includes a compressor impeller 11 that is rotationally driven by the rotation of the turbine rotor 5a, and a compressor housing 12 as a housing that rotatably accommodates the compressor impeller 11. The turbine housing 5b and the compressor housing 12 are connected to each other via the center housing 6.

The compressor impeller 11 has a rotating shaft 11a common to the turbine rotor 5a. The rotation shaft 11a is arranged so as to extend in the front-rear direction.

The turbine rotor 5a is fixed to the front end of the rotating shaft 11a. The compressor impeller 11 is fixed to the rear end of the rotating shaft 11a. The center housing 6 is formed in a cylindrical shape extending in the front-rear direction, and rotatably accommodates a rotating shaft 11a located between the turbine rotor 5a and the compressor impeller 11.

As shown in FIG. 2, the outer peripheral portion of the compressor impeller 11 is enlarged in diameter toward the front. A plurality of blades 11b arranged at intervals in the circumferential direction are formed on the outer peripheral portion of the compressor impeller 11.

The compressor housing 12 constitutes a part of the intake passage 3. The compressor housing 12 has an intake inlet portion 13 arranged on the upstream side of the compressor impeller 11 in the intake flow direction, and a scroll portion 14 arranged on the downstream side of the compressor impeller 11 and extending in the circumferential direction. Further, the compressor housing 12 is connected to the downstream end of the intake inlet portion 13, and extends radially outward from the position of the shroud portion 15 extending along the outer peripheral portion of the compressor impeller 11 and the outer peripheral end of the compressor impeller 11, and the shroud. It has a diffuser unit 16 for connecting the unit 15 and the scroll unit 14.

The intake inlet portion 13 is formed in a tubular shape and is coaxially arranged at a position immediately upstream (illustrated, rear position) of the compressor impeller 11. The upstream end of the intake inlet portion 13 is connected to the downstream end of the intake pipe 3b on the upstream side of the compressor 10 via a rubber pipe joint 17.

The scroll portion 14 has a flow path cross-sectional area larger than that of the diffuser portion 16. Further, the scroll portion 14 is formed so that the cross-sectional area of the flow path increases as the intake air is directed from the upstream side to the downstream side.

As shown in FIG. 3, the scroll portion 14 makes one round in the circumferential direction, and then extends to the right from the position of the upper end portion along the intake flow direction. An intake / discharge port 18 is formed at the downstream end of the scroll portion 14. The intake / discharge port 18 is formed in a tubular shape and is connected to the upstream end of the intake pipe 3b on the downstream side of the compressor 10 via a rubber pipe joint 19.

On the other hand, as shown in FIG. 2, the scroll portion 14 has a front surface portion 14a, a rear surface portion 14b, and an outer peripheral portion 14c.

The front surface portion 14a is arranged to face the turbine housing 5b (see FIG. 1) and extends perpendicular to the axial direction of the rotating shaft 11a. Further, a gas housing 31 described later is connected to the front surface portion 14a. The front surface portion 14a of the present embodiment is formed in an annular shape in which the central portion in the radial direction is opened, and the inner peripheral portion of the front surface portion 14a is a flange portion provided at the rear end portion of the center housing 6. 6a is fitted and fixed.

In the compressor 10 of the present embodiment, the compressor impeller 11 is rotationally driven by the rotation of the turbine rotor 5a (see FIG. 1) while the internal combustion engine 1 is in operation. As a result, in the compressor housing 12, the intake air introduced from the intake air inlet portion 13 to the shroud portion 15 is compressed as it flows through the diffuser portion 16 and the scroll portion 14 in order. Then, as shown in FIG. 3, the compressed intake air is discharged from the intake air discharge port 18 of the scroll portion 14 to the intake pipe 3b.

Next, the blow-by gas recirculation device 100 of the present embodiment will be described. In the figure, the dotted arrow B indicates the flow of blow-by gas. As is well known, blow-by gas is gas that leaks into the crankcase from the gap between the cylinder and the piston.

As shown in FIG. 1, an in-engine passage 7 through which blow-by gas flows is provided inside the engine body 2. The engine passage 7 extends from the inside of the crankcase through the inside of the cylinder block and the cylinder head to the inside of the head cover 2a.

An outlet 7a of the passage 7 in the engine is formed on the upper surface of the head cover 2a. The upstream end of the blow-by gas pipe 8 is connected to the outlet 7a of the passage 7 in the engine.

The blow-by gas pipe 8 is made of a resin material such as rubber and is arranged outside the internal combustion engine 1. An oil separator 9 is provided in the middle of the blow-by gas pipe 8. The oil separator 9 has a built-in filter element (not shown) and is configured to separate and remove oil from blow-by gas.

In the oil separator 9, oil is separated from the blow-by gas flowing through the blow-by gas pipe 8. The oil separated from the blow-by gas is returned to the crankcase through an oil return pipe (not shown).

The blow-by gas recirculation device 100 includes a gas introduction port 20 as an introduction port for introducing blow-by gas into the intake inlet portion 13 of the compressor 10.

The gas introduction port 20 is provided at the intake inlet portion 13. The downstream end of the blow-by gas pipe 8 is connected to the gas introduction port 20 via an adjacent passage 30 and a connecting pipe 40, which will be described later.

In the present embodiment, during the operation of the internal combustion engine 1, the blow-by gas in the crankcase flows through the engine passage 7, the blow-by gas pipe 8, the adjacent passage 30, and the connecting pipe 40 in this order, and flows from the gas introduction port 20 to the compressor 10. It is introduced into the intake inlet portion 13.

By the way, although not shown, in a general blow-by gas recirculation device, the downstream end of the blow-by gas pipe 20 is directly connected to the gas introduction port 20.

However, since the blow-by gas pipe, the gas inlet, and the intake inlet portion in the vicinity thereof are cooled by the outside air, the temperature of the blow-by gas is lowered as the blow-by gas moves from the upstream side to the downstream side. Then, when the temperature of the blow-by gas becomes equal to or lower than the dew point temperature, condensed water is generated inside these.

In particular, since the downstream end of the blow-by gas pipe, the gas inlet, and the intake inlet are cooled by the intake air, condensed water tends to be generated inside them. Further, in an environment where the atmospheric temperature is low, the condensed water freezes inside these, and the frozen ice may flow to the downstream side, damaging the compressor (particularly, the compressor impeller). In addition, the gas inlet and the like may be blocked by the frozen ice.

Therefore, as shown in FIG. 2, the blow-by gas recirculation device 100 of the present embodiment is provided on the upstream side in the blow-by gas flow direction with respect to the gas introduction port 20, and includes an adjacent passage 30 adjacent to the scroll portion 14 of the compressor 10. ..

As shown in FIG. 3, the adjacent passage 30 extends in the circumferential direction along the scroll portion 14.
Further, the adjacent passage 30 of the present embodiment is composed of a gas housing 31 attached to the front surface portion 14a of the scroll portion 14.

The gas housing 31 is made of a metal material or a resin material, and is formed in an annular shape that makes one round in the circumferential direction along the scroll portion 14.

As shown in FIG. 2, a recess 31a is formed at a position between the inner peripheral portion and the outer peripheral portion of the gas housing 31 so as to project forward in a semicircular cross section. The recess 31a is formed in an annular shape that makes one round in the circumferential direction of the gas housing 31. In the present embodiment, the adjacent passage 30 is defined by the front surface of the scroll portion 14 and the inner surface of the recess 31a.

As shown in FIG. 3, the adjacent passage 30 has a gas inlet 30a for introducing blow-by gas and a gas outlet 30b for discharging blow-by gas.

The gas inlet 30a and the gas outlet 30b are formed in a tubular shape protruding radially outward (on the left side in the illustrated example) from the recess 31a. Further, the gas inlet 20 of the compressor 10 is formed in a tubular shape protruding radially outward (on the left side in the illustrated example) from the intake inlet portion 13.

The downstream end of the blow-by gas pipe 8 is fitted and connected to the gas inlet 30a, and the upstream end of the connecting pipe 40 made of a resin material such as rubber is fitted and connected to the gas outlet 30b. .. Further, the downstream end of the connecting pipe 40 is fitted and connected to the gas introduction port 20 (see FIG. 2) of the compressor 10.

Further, the gas inlet 30a and the gas outlet 30b of the present embodiment are arranged so as to be spaced apart from each other in the circumferential direction and close to each other.

Further, the adjacent passage 30 of the present embodiment has a partition wall 30c that separates the gas inlet 30a and the gas outlet 30b, and makes substantially one round in the circumferential direction from the gas inlet 30a to the gas outlet 30b.

The partition wall 30c is formed in a plate shape and is provided at a position between the gas inlet 30a and the gas outlet 30b in the circumferential direction. Further, the partition wall 30c is integrally formed in advance on the inner surface of the recess 31a by welding or the like.

The gas housing 31 of the present embodiment is fixed to the front surface portion 14a of the scroll portion 14 by bolting, welding, or the like with the center housing 6 inserted through the center portion thereof. Further, at this time, the partition wall 30c is brought into close contact with the front surface portion 14a of the scroll portion 14.

In the adjacent passage 30 of the present embodiment, blow-by gas is introduced from the blow-by gas pipe 8 through the gas inlet 30a while the internal combustion engine 1 is operating, and the blow-by gas is introduced from the gas inlet 30a toward the gas outlet 30b in the circumferential direction (in the example of FIG. 3 in the example of FIG. 3). After flowing about one round (counterclockwise), the gas is discharged to the connecting pipe 40 through the gas outlet 30b.

On the other hand, as shown in FIG. 2, in the compressor 10, as the intake air flows through the diffuser unit 16 and the scroll unit 14 in order, the intake air is compressed and the temperature is raised. As a result, the heated intake heat is transferred from the scroll portion 14 to the adjacent passage 30, and the blow-by gas flowing through the adjacent passage 30 can be heated. Then, the blow-by gas heated in the adjacent passage 30 can be introduced from the connecting pipe 40 into the intake inlet portion 13 of the compressor 10 through the gas introduction port 20.

As a result, it is possible to suppress the generation and freezing of condensed water in the connecting pipe 40, the gas introduction port 20, and the intake inlet portion 13 even in an environment where the atmospheric temperature is low.

Therefore, the blow-by gas recirculation device 100 of the present embodiment can prevent the condensed water from freezing even in an environment where the atmospheric temperature is low. As a result, damage to the compressor 10 (particularly, the compressor impeller 11) due to frozen ice can be suppressed, and blockage of the connecting pipe 40 and the intake inlet portion 13 due to frozen ice can be suppressed.

Further, the adjacent passage 30 of the present embodiment extends in the circumferential direction along the scroll portion 14. As a result, a sufficient heating area of the adjacent passage 30 can be secured, the blow-by gas can be retained in the adjacent passage 30 for a long time, and a large amount of intake heat can be transferred to the blow-by gas. As a result, the blow-by gas can be efficiently heated by the compressed intake air.

Further, according to the present embodiment, by providing the partition wall 30c, it is possible to prevent the blow-by gas from short-cutting from the gas inlet 30a to the gas outlet 30b. As a result, the flow path from the gas inlet 30a to the gas outlet 30b can be lengthened, and the heating efficiency of blow-by gas can be improved.

On the other hand, the above embodiment can be a modification or a combination thereof as follows. In the following description, the same reference numerals are used for the same components as those in the above embodiment, and detailed description thereof will be omitted.

(First modification)
Although not shown, the gas introduction port 20 may introduce blow-by gas into the intake passage 3 on the upstream side of the intake inlet portion 13 of the compressor 10. In the first modification, the gas introduction port 20 is provided in the intake pipe 3b on the upstream side of the compressor 10.

(Second modification)
The adjacent passage 30 may be formed of a pipe material instead of the gas housing 31. The adjacent passage of the second modification is composed of a pipe material formed integrally with or separately from the blow-by gas pipe, extends in the circumferential direction along the scroll portion, and is fixed adjacent to the front portion of the scroll portion.

If it is an adjacent passage of the second modification, it is possible to use a general-purpose pipe material instead of a dedicated housing such as the gas housing 31, so that an increase in manufacturing cost can be suppressed. The pipe material may be, for example, a half-split pipe (half pipe).

(Third modification example)
The adjacent passage 30 may be arranged adjacent to an arbitrary position of the scroll portion 14. For example, the adjacent passage of the third modification is arranged adjacent to the rear surface portion or the outer peripheral portion of the scroll portion.

(Fourth modification)
The adjacent passage 30 may be connected to the gas introduction port 20 by any structure other than the connecting pipe 40. For example, in the fourth modification, the adjacent passage and the gas introduction port are connected by a connection passage integrally formed with the compressor housing 12.

(Fifth modification)
The adjacent passage 30 does not have to make approximately one round in the circumferential direction. The adjacent passage of the fifth modification is formed so as to make a half circumference in the circumferential direction from the gas inlet to the gas outlet, and the partition wall is omitted. Further, the adjacent passage 30 does not have to extend in the circumferential direction along the scroll portion 14.

Although the embodiments of the present disclosure have been described in detail above, the embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications and applications included in the idea of the present disclosure defined by the claims. Examples, equivalents are included in this disclosure. Therefore, this disclosure should not be construed in a limited way and may be applied to any other technique that falls within the scope of the ideas of this disclosure.

1 Internal combustion engine 3 Intake passage 3b Intake pipe 5 Turbocharger 6 Center housing 10 Compressor 11 Compressor impeller 12 Compressor housing (housing)
13 Intake inlet 14 Scroll 20 Gas inlet (introduction port)
30 Adjacent passage 100 Blow-by gas recirculation device A Intake B Blow-by gas G Exhaust

Claims (3)

It is a blow-by gas recirculation device for internal combustion engines.
The internal combustion engine includes an intake passage and a turbocharger compressor provided in the intake passage.
The compressor comprises a compressor impeller and a housing that rotatably houses the compressor impeller.
The housing is arranged in the intake inlet portion located on the upstream side of the compressor impeller and on the downstream side of the compressor impeller in the intake flow direction, and extends in the circumferential direction at a position on the outer peripheral side of the compressor impeller. Has a scroll part,
The blow-by gas recirculation device is
An introduction port for introducing blow-by gas into the intake inlet portion or the intake passage on the upstream side of the intake inlet portion, and
A blow-by gas recirculation device provided on the upstream side in the blow-by gas flow direction with respect to the introduction port and provided with an adjacent passage adjacent to the scroll portion. The blow-by gas recirculation device according to claim 1, wherein the adjacent passage extends in the circumferential direction along the scroll portion. The adjacent passage
It has a gas inlet for introducing blow-by gas, a gas outlet for discharging blow-by gas, and a partition wall for partitioning the gas inlet and the gas outlet.
The blow-by gas recirculation device according to claim 2, wherein the blow-by gas recirculation device extends in the circumferential direction from the gas inlet to the gas outlet.

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