JP2021175886A - Blow-by gas treatment device - Google Patents

Abstract

To provide a blow-by gas treatment device capable of suppressing generation of white smoke caused by moisture in blow-by gas.SOLUTION: A blow-by gas treatment device 100 for an internal combustion engine 1 includes: a blow-by gas passage 10 having an outlet 10a opened to the atmosphere; and a mixer member 20 provided in the outlet 10a and stirring blow-by gas.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a blow-by gas processing apparatus.

In an internal combustion engine, a blow-by gas treatment device that releases blow-by gas leaking into a crankcase from a gap between a piston and a cylinder to the atmosphere from a blow-by gas passage is known.

Japanese Unexamined Patent Publication No. 2010-248971

However, in the above blow-by gas treatment apparatus, white smoke may be generated around the outlet of the blow-by gas passage due to the moisture in the blow-by gas. In this case, the cause of the white smoke may be mistaken as an abnormality of the internal combustion engine, which may lead to unnecessary maintenance.

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 treatment apparatus capable of suppressing the generation of white smoke due to moisture in blow-by gas.

According to one aspect of the present disclosure, a blow-by gas processing apparatus for an internal combustion engine, a blow-by gas passage having an outlet portion open to the atmosphere, and a mixer member provided inside the outlet portion to agitate the blow-by gas. , A blow-by gas processing apparatus is provided.

Preferably, the mixer member comprises a plurality of fins that generate a swirling flow around the outlet.

Further, the mixer member is provided so as to be inclined with respect to the axial direction of the outlet portion, and includes a plurality of plate-shaped members arranged in parallel with each other.

Further, the mixer member includes a grid-like member formed in a grid pattern in a cross-sectional view perpendicular to the axial direction of the outlet portion.

According to the blow-by gas treatment apparatus of the present disclosure, it is possible to suppress the generation of white smoke due to the moisture in the blow-by gas.

It is an overall block diagram of an internal combustion engine including a blow-by gas processing apparatus. It is an enlarged sectional view of the blow-by gas processing apparatus shown in the part II of FIG. FIG. 2 is an enlarged cross-sectional view taken along the line III-III of FIG. FIG. 2 is an enlarged cross-sectional view taken along the line IV-IV of FIG. It is an enlarged cross-sectional view of the blow-by gas processing apparatus of the 1st modification. FIG. 5 is an enlarged cross-sectional view taken along the line VI-VI of FIG. It is an enlarged cross-sectional view of the blow-by gas processing apparatus of the 2nd modification. FIG. 7 is an enlarged cross-sectional view taken along the line VIII-VIII of 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. 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.

First, the overall configuration of the internal combustion engine 1 of the present embodiment will be described with reference to FIG. In the figure, the white arrow A indicates the flow of intake air, and the black arrow G indicates the flow of exhaust gas.

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 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. 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 a cylinder block 2a, a cylinder head 2b connected to the upper part of the cylinder block 2a, a crankcase 2c integrally formed in the lower part of the cylinder block 2a, and an oil pan connected to the lower part of the crankcase 2c. 2d and. Further, the engine body 2 includes a head cover 2e connected to the upper part of the cylinder head 2b and a cooling fan 2f arranged in front of and in the vicinity of the crankcase 2c.

Although not shown, the cylinder block 2a is provided with a plurality of cylinders, and the cylinders accommodate pistons. A valve operating mechanism such as a camshaft is attached to the cylinder head 2b, and the valve operating mechanism is covered from above by the head cover 2e.

The cooling fan 2f is driven by the rotation of the crankshaft. The cooling fan 2f is arranged behind and near the radiator for cooling the engine cooling water, and generates an air flow passing through the radiator.

The intake passage 3 includes an intake manifold (not shown) connected to the cylinder head 2b and an intake pipe 3a connected to the upstream end of the intake manifold.

The intake pipe 3a is provided with an air cleaner (not shown), a compressor 5C of the turbocharger 5, and an intercooler (not shown) in this order from the upstream side.

The exhaust passage 4 includes an exhaust manifold 4a connected to the cylinder head 2b and an exhaust pipe 4b arranged on the downstream side of the exhaust manifold 4a.

A turbine 5T of a turbocharger 5 is provided between the exhaust manifold 4a and the exhaust pipe 4b. The exhaust pipe 4b is provided with an exhaust throttle valve 4c and a post-treatment unit (not shown) for purifying the exhaust in this order from the upstream side.

Although not shown, the aftertreatment unit includes an injector in the exhaust pipe that injects fuel into the exhaust pipe 4b, a diesel oxidation catalyst (DOC: Diesel Oxidation Catalyst), and a diesel particulate filter (DPF: Diesel Particulate Filter). .. The DOC oxidizes and purifies the hydrocarbon HC and carbon monoxide CO contained in the unburned components in the exhaust gas, and raises the temperature of the exhaust gas by the heat of oxidation. The DPF collects particulate matter (PM: Particulate Matter) contained in the exhaust gas. Further, the PM deposited on the DPF is burned and removed by the exhaust gas heated by the DOC.

The exhaust throttle valve 4c is an electronically controlled flow rate adjusting valve (butterfly valve) that adjusts the flow rate of the exhaust gas flowing through the exhaust pipe 4b. The exhaust throttle valve 4c is electronically controlled by an electronic control unit (ECU) (not shown), and is closed during filter regeneration control or warm-up promotion control of the internal combustion engine 1.

The filter regeneration control is a control in which fuel is injected from an injector in the exhaust pipe and high-temperature exhaust gas is made to flow into the DPF from the DOC to burn and remove PM accumulated on the DPF. On the other hand, the warm-up promotion control is a control that promotes the warm-up of the internal combustion engine 1 during idle operation immediately after the start of the internal combustion engine 1.

Next, the configuration of the blow-by gas processing apparatus 100 of the present embodiment will be described with reference to FIGS. 1 to 3. In the figure, the dotted arrow B indicates the flow of blow-by gas. Further, in FIG. 2, the alternate long and short dash line C indicates the central axis of the blow-by gas pipe 10. Further, in FIG. 1, a wavy dotted arrow F indicates the flow of air blown from the cooling fan 2f.

As shown in FIG. 1, an in-engine passage 6 through which blow-by gas flows is provided inside the engine body 2. As is well known, blow-by gas is gas that leaks into the crankcase 2c from the gap between the cylinder and the piston.

The in-engine passage 6 passes through the inside of the cylinder block 2a and the cylinder head 2b from the inside of the crankcase 2c and extends into the head cover 2e. An outlet 6a of the passage 6 in the engine is formed on the upper surface of the head cover 2e. The upstream end of the blow-by gas pipe 10, which will be described later, is connected to the outlet 6a of the passage 6 in the engine.

The blow-by gas processing device 100 includes a blow-by gas pipe 10 as a blow-by gas passage whose outlet portion 10a is open to the atmosphere, and a mixer member 20 provided inside the outlet portion 10a to agitate the blow-by gas.

The blow-by gas pipe 10 is made of a resin material such as rubber and is arranged outside the engine body 2. An oil separator 7 for removing oil from the blow-by gas is provided in the middle of the blow-by gas pipe 10.

The oil separator 7 has a built-in filter element 7a and is installed on the upper surface of the head cover 2e. However, the type and position of the oil separator 7 may be arbitrary, and may be, for example, a centrifugal oil separator having no filter element.

In the oil separator 7, oil is separated from the blow-by gas introduced therein. The oil separated from the blow-by gas is returned to the crankcase 2c through an oil return passage (not shown).

The outlet portion 10a of the blow-by gas pipe 10 is arranged close to the right side surface portion of the front end portion of the engine body 2 (crankcase 2c in this embodiment) and extends downward.

The outlet portion 10a of the blow-by gas pipe 10 is arranged so that the air F blown from the cooling fan 2f hits the blow-by gas opened to the atmosphere. The outlet portion 10a of the present embodiment is arranged behind and near the cooling fan 2f.

As shown in FIG. 2, the mixer member 20 is arranged immediately upstream of the downstream end of the outlet portion 10a. Further, the mixer member 20 includes a plurality of (six in this embodiment) fins 21 that generate a swirling flow around the axis of the outlet portion 10a. Further, the mixer member 20 includes a shaft portion 22 and a cylinder portion 23 arranged coaxially with the central shaft C of the outlet portion 10a. The hatched portion X in the drawing represents a front surface (upper surface) of each fin 21.

As shown in FIG. 3, each fin 21 of the present embodiment extends radially outward from the shaft portion 22 and is fixed to the inner peripheral portion of the tubular portion 23. The tubular portion 23 is formed in a cylindrical shape, is inserted into the outlet portion 10a from below, and is fitted and fixed.

Further, as shown in FIG. 4, each fin 21 faces the same circumferential direction (clockwise in FIG. 3 in the illustrated example) toward the downstream side in the axial direction of the blow-by gas pipe 10, that is, downward. Is tilted to. The inclination angle of the fins 21 with respect to the axial direction of the blow-by gas pipe 10 is set to an angle suitable for stirring or turning the blow-by gas (for example, 45 °).

Next, the operation and effect of the blow-by gas treatment device 100 according to the present embodiment will be specifically described.

As shown in FIG. 1, in the present embodiment, during the operation of the internal combustion engine 1, the blow-by gas in the crankcase 2c flows through the engine passage 6 and the blow-by gas pipe 10 in order, and the outlet portion of the blow-by gas pipe 10 It is released to the atmosphere from 10a.

In a general blow-by gas processing apparatus, a mixer member is not provided inside the outlet portion of the blow-by gas pipe, and the blow-by gas is not agitated at the outlet portion of the blow-by gas pipe. Therefore, the blow-by gas is discharged into the atmosphere from the outlet portion to the downstream side in the axial direction, that is, downward, without changing the direction of the flow.

However, in such a blow-by gas treatment device, white smoke may be generated around the outlet of the blow-by gas pipe due to the moisture in the blow-by gas. That is, in an environment where the atmospheric temperature is low, water vapor, which is an invisible gas contained in blow-by gas, is cooled by the outside air immediately after being discharged from the blow-by gas pipe. Then, when the temperature of the water vapor becomes equal to or lower than the dew point temperature, the water vapor condenses and further aggregates to appear as visible water droplets, that is, steam. This steam is the true identity of white smoke.

In particular, when the exhaust throttle valve is closed during filter regeneration control or warm-up promotion control during idle operation of the internal combustion engine, the fuel injection amount increases as the load on the internal combustion engine increases. As a result, the amount of water in the blow-by gas increases, so that white smoke tends to be generated easily.

In this case, the cause of the white smoke may be mistaken as an abnormality of the internal combustion engine, which may lead to unnecessary maintenance.

On the other hand, as shown in FIG. 2, in the blow-by gas processing apparatus 100 of the present embodiment, the mixer member 20 is provided inside the outlet portion 10a of the blow-by gas pipe 10. By stirring the blow-by gas, the mixer member 20 can change the direction of the flow of the blow-by gas discharged from the outlet portion 10a from the direction toward the downstream side (downward) in the axial direction to the direction toward the outside in the radial direction. ..

In particular, the mixer member 20 of the present embodiment swirls the blow-by gas around the axis of the outlet portion 10a by a plurality of fins 21 and utilizes the centrifugal force generated by the swirling of the blow-by gas to be radially outside from the outlet portion 10a. Blow-by gas can be blown off and discharged.

As a result, the water vapor contained in the blow-by gas can flow outward in the radial direction from the outlet portion 10a and diffuse into the atmosphere. As a result, even when the temperature of water vapor becomes lower than the dew point temperature in an environment where the atmospheric temperature is low, the aggregation of water vapor is suppressed and the generation of steam (white smoke) can be suppressed.

Therefore, the blow-by gas treatment device 100 of the present embodiment can suppress the generation of white smoke due to the moisture in the blow-by gas. As a result, it is possible to prevent unnecessary maintenance from being performed by misidentifying that the cause of the white smoke is an abnormality of the internal combustion engine 1. Further, if white smoke is generated, the cause of the white smoke can be identified by focusing on the causes other than the moisture in the blow-by gas, so that the maintenance can be made more efficient.

On the other hand, as shown in FIG. 1, the outlet portion 10a of the blow-by gas pipe 10 is arranged so that the air F blown from the cooling fan 2f hits the blow-by gas opened to the atmosphere. As a result, the water vapor in the blow-by gas can be further diffused by blowing air from the cooling fan 2f.

The above-described 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)
The mixer member may be of any type and shape. As shown in FIGS. 5 and 6, the mixer member 30 of the first modification is provided so as to be inclined with respect to the axial direction of the outlet portion 10a instead of the fin 21 and the shaft portion 22 described in the first embodiment. A plurality of (four in the illustrated example) plate-shaped members 31 are provided.

The plate-shaped members 31 are arranged in parallel with each other. Further, the plate-shaped member 31 is formed in a flat plate shape extending in the left-right direction, and is inclined toward the rear from the upper side to the lower side. Both ends 31a and 31b (see FIG. 6) of the plate-shaped member 31 in the left-right direction are fixed to the inner peripheral portion of the tubular portion 23. The inclination angle of the plate-shaped member 31 with respect to the axial direction of the outlet portion 10a is set to an angle suitable for stirring blow-by gas (for example, 45 °).

As shown in FIG. 5, in the first modification, the direction of the blow-by gas flow is changed by the plate-shaped member 31, so that the blow-by gas is agitated inside the outlet portion 10a. Thereby, the direction of the flow of the blow-by gas discharged from the outlet portion 10a can be changed from the direction toward the downstream side (downward) in the axial direction to the direction toward the outer side in the radial direction. As a result, the same effect as that of the above embodiment can be obtained.

(Second modification)
As shown in FIGS. 7 and 8, the mixer member 40 of the second modification has a cross-sectional view perpendicular to the axial direction of the outlet portion 10a instead of the fin 21 and the shaft portion 22 described in the first embodiment (FIG. 7). 8), the grid-like member 41 formed in a grid-like manner is provided.

The grid-like member 41 is formed in a grid shape or a square grid shape arranged in the front-rear direction and the left-right direction, and has an axial length suitable for stirring blow-by gas. Further, the front, rear, left and right end portions 41a of the lattice-shaped member 41 are fixed to the inner peripheral portion of the tubular portion 23.

In the second modification, a part of the blow-by gas hits the grid-like member 41 and is agitated. As a result, the direction of the flow of the blow-by gas discharged from the outlet portion 10a can be changed from the direction toward the downstream side in the axial direction to the direction toward the outside in the radial direction. As a result, the same effect as that of the above embodiment can be obtained.

(Third modification example)
Although not shown, the mixer member may be provided at an arbitrary position inside the outlet portion. For example, in the third modification, the mixer member is arranged at the downstream end of the outlet portion.

1 Internal combustion engine 10 Blow-by gas pipe (blow-by gas passage)
10a Outlet 20 Mixer member 21 Fin 100 Blow-by gas processing device B Blow-by gas

Claims (4)

It is a blow-by gas processing device for internal combustion engines.
A blow-by gas passage with the outlet open to the atmosphere,
A blow-by gas processing apparatus provided inside the outlet portion, comprising a mixer member for stirring blow-by gas. The blow-by gas treatment apparatus according to claim 1, wherein the mixer member includes a plurality of fins that generate a swirling flow around the axis of the outlet portion. The blow-by gas treatment apparatus according to claim 1, wherein the mixer member is provided so as to be inclined with respect to the axial direction of the outlet portion, and includes a plurality of plate-shaped members arranged in parallel with each other. The blow-by gas treatment apparatus according to claim 1, wherein the mixer member includes a grid-like member formed in a grid pattern in a cross-sectional view perpendicular to the axial direction of the outlet portion.

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