JP2014159746A - Positive crankcase ventilation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive crankcase ventilation system which unfailingly melts freezing of moisture included in a blow-by gas exhausted from an engine even in a severe cold region and thereby prevents the clogging of a blow-by gas hose at low costs.SOLUTION: A positive crankcase ventilation system of an internal combustion engine 1 includes: a turbocharger 2 which supercharges the internal combustion engine; heating means which branches a coolant R in the internal combustion engine to cool the turbocharger and then heats a blow-by gas by the coolant R returning to a water pump 63; and a blow-by gas hose 3 which introduces the blow-by gas into an intake pipe 24 at the upstream side of the turbocharger. An introduction part 33 where the blow-by gas hose is connected with the intake pipe is heated by the heating means to melt condensed water freezed in the introduction part.

Description

  The present invention relates to a blow-by gas reduction device for preventing moisture contained in blow-by gas from freezing in a pipe line for introducing blow-by gas of an internal combustion engine into an intake system passage.

In general, a predetermined gap is provided between a piston and a cylinder of an internal combustion engine so that the piston can slide smoothly. In order to fill this gap, the piston is provided with a plurality of piston rings with intervals in the sliding direction of the piston. The piston ring is fitted and held in a piston ring groove provided in the piston.
The piston ring has an elastic force that expands in the diametrical direction, and is brought into close contact with the inner peripheral surface of the cylinder by the elastic force and slides in the axial direction of the cylinder together with the piston.
In this way, the combustion gas that has become high pressure in the combustion chamber on the upper surface of the piston and the unburned gas during the piston compression process do not flow out into the crankcase.

However, the piston ring and the piston ring groove are fitted with a slight gap in consideration of the thermal deformation of the piston ring.
Therefore, the high-pressure gas on the upper surface of the piston leaks from the gap to the crankcase side and is called so-called blow-by gas.
Blow-by gas contains unburned hydrocarbon (HC) and a lot of moisture.
When blow-by gas accumulates in the crankcase, the pressure in the crankcase rises, acts as pressure on the back side of the piston, and becomes an internal resistance of the internal combustion engine, so it needs to be discharged.
However, if unburned hydrocarbon (HC) is released into the atmosphere as it is, the blowby gas is mixed into the intake system passage and burned in the combustion chamber of the internal combustion engine.

However, as described above, blow-by gas contains unburned hydrocarbons (HC) and a large amount of moisture.
The blow-by gas is condensed from the internal combustion engine and introduced into the intake passage, and is stored in the blow-by gas introduction member.
In extremely cold regions, when the stored condensed water freezes, the flow of blow-by gas is obstructed or the internal passage of the blow-by gas introduction member is blocked, and the blow-by gas cannot be introduced into the intake system. was there.

As such a correspondence, Patent Document 1 is disclosed.
According to Patent Document 1, in the anti-freezing structure of the blow-by gas passage integrally provided with a resin-made intake manifold side union connected to the intake manifold, the outer periphery of the pipe constituting the blow-by gas passage is added to the outer periphery of the pipe. There is a technical disclosure in which a warm pipe is fixed, the warming pipe is communicated with a water pipe that communicates the engine and a radiator, and the engine-side coolant is caused to flow into the warming pipe.

JP 2008-215191 A

In general, the cooling system of an internal combustion engine has a structure in which when the engine is not sufficiently warmed, the coolant circulates in the internal combustion engine and raises the temperature of the coolant early, so that it does not flow to the radiator side. ing.
When the coolant temperature rises sufficiently and the thermostat opens, the coolant flows from the engine to the radiator.
However, according to Patent Document 1, the water pipe has a structure in which an engine and a radiator are connected.
In this structure, when the coolant flows from the engine to the radiator, the coolant flows to the water pipe, and the pipe in the blow-by gas passage is heated by the heating pipe.
Therefore, in extremely cold regions, the temperature of the cooling water may not be sufficiently heated, and the thermostat may be repeatedly opened and closed.
In that case, the case where the coolant flows in the water pipe and the case where it does not flow are repeated.
In such a situation, since the temperature of the cooling water does not become sufficiently high, there is a factor that the blow-by gas passage cannot be sufficiently heated.

  The present invention has been made in view of the above-described problems of the prior art, and reliably freezes the moisture contained in the blow-by gas discharged from the engine even in extremely cold regions, thereby reducing the blockage of the blow-by gas hose. An object of the present invention is to provide a blow-by gas reduction device that prevents costs.

In order to achieve the above object, according to the present invention, there is provided a blow-by gas reduction device for reducing blow-by gas leaked into a crankcase of an internal combustion engine to an intake pipe of an intake system path,
A turbocharger that is driven by exhaust gas discharged from the internal combustion engine and compresses intake air to supercharge the internal combustion engine;
A heating means for warming the blow-by gas with the cooling liquid returning to the water pump of the internal combustion engine after cooling the turbocharger by diverting a cooling liquid for cooling the internal combustion engine from the internal combustion engine;
A blowby gas introduction member for introducing the blowby gas into the intake pipe on the upstream side of the compressor of the turbocharger,
The condensate frozen inside the introduction part is melted by heating the introduction part where the blow-by gas introduction member and the intake pipe are connected by the heating means. A blow-by gas reduction device can be provided.

According to the present invention, a part of the coolant that has cooled the internal combustion engine is diverted to cool the turbocharger, and the coolant that is further heated by the turbocharger is used to introduce the blow-by gas introduction member and the intake pipe. Since the condensed water frozen at the introduction portion is melted, the blow-by hose can be effectively prevented from being blocked by freezing.
Since the coolant of the heating means is divided from the internal combustion engine and returns to the water pump of the internal combustion engine, the introduction portion can be heated even when the thermostat is not open.
Furthermore, since the structure is such that the coolant of the internal combustion engine is divided as a heat source for preventing freezing, the cost can be reduced.

  In the present invention, it is preferable that the introduction portion includes a connector fixed to an intake pipe and connected to the blow-by gas introduction member, and the connector is made of a copper material.

By adopting such a configuration, the connector is manufactured from a copper material having a high thermal conductivity.
Therefore, since the connector is heated by the coolant that has become high temperature by cooling the turbocharger, the condensed water frozen inside the connector is efficiently melted.

  In the present invention, it is preferable that the introduction portion is disposed in an intake pipe in the vicinity of a connection portion between the intake pipe and the compressor.

  By adopting such a configuration, the introduction part is disposed in the vicinity of the connection part between the intake pipe and the compressor, so that the natural heat dissipation of the coolant that has cooled the turbocharger can be minimized, and the heating effect of the introduction part Will improve.

  In the present invention, it is preferable that the connector is formed in a linear shape.

By setting it as such a structure, blowby gas contains much moisture. Therefore, when flowing through the bent portion, moisture having a large specific gravity is easily separated from the blow-by gas and is likely to be frozen.
Therefore, by making the connector straight, it is easy to introduce blow-by gas into the intake pipe, thereby preventing freezing associated with the generation of condensed water.

  In the present invention, it is preferable that a concave groove having substantially the same curvature as that of the outer peripheral portion of the cooling member in the axial direction is formed along the circumferential direction on the outer peripheral surface of the connector.

  By adopting such a configuration, a concave groove having substantially the same curvature as the outer peripheral portion of the axial sectional shape of the cooling member is formed on the outer peripheral surface of the connector along the circumferential direction of the outer periphery of the connector. The contact area between the connector and the connector increases, the amount of heat transferred from the cooling member to the connector increases, and effective freezing and thawing becomes possible.

  According to the present invention, it is possible to provide a blow-by gas reduction device that reliably melts freezing of moisture contained in blow-by gas discharged from an engine even in extremely cold regions and prevents blockage of the blow-by hose at low cost.

1 shows an overall schematic configuration diagram of an internal combustion engine having a blow-by gas reduction device in an embodiment of the present invention. FIG. The schematic explanatory drawing of the cooling system in the embodiment of the present invention is shown. (A) is an enlarged view of a Z portion in FIG. 2, and (B) is a view taken in the direction of arrow Y in (A). The modification of the connector shape of an intake pipe is shown. (A) is a detailed view of the mounting portion of the connector, and (B) is a view taken in the direction of arrow X in (A). The conventional connector attachment part shape figure is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to specific examples unless otherwise specifically described. Only.

FIG. 1 shows an overall schematic configuration diagram of an internal combustion engine having a blow-by gas reduction device according to an embodiment of the present invention.
Reference numeral 1 denotes an automobile internal combustion engine body (hereinafter abbreviated as an internal combustion engine). The internal combustion engine 1 includes a piston 11a, a crankshaft 11b for converting the vertical movement of the piston 11a into a rotational movement, and the piston 11a in the axial direction. A crankcase 11 having a built-in cylinder 11c that reciprocally slides, a cylinder head 16 that forms part of the intake / exhaust flow passage and the combustion chamber 12 above the crankcase 11, a rocker cover 13 above the cylinder head 16, etc. Is equipped.
Inside the rocker cover 13, there are provided a valve drive system (not shown) for operating the intake valve 16a for introducing and stopping introduction of intake air into the combustion chamber and the exhaust valve 16b for discharging and stopping combustion gas. Has been.

Reference numeral 2 denotes a turbocharger. The turbocharger 2 is attached to an exhaust manifold 14 that discharges exhaust gas burned in the combustion chamber 12 of the internal combustion engine 1.
The turbocharger 2 introduces exhaust gas into the exhaust turbine 21 via the exhaust manifold 14, and the exhaust turbine 21 rotates at a high speed by the pressure of the exhaust gas.
The exhaust gas that has driven the exhaust turbine 21 is purified by an exhaust gas purification device (not shown) disposed in the exhaust pipe 23 and is released to the atmosphere.
The intake passage for supplying intake air to the combustion chamber 12 introduces an air cleaner 23 that removes dust from the intake air and the compressor 22 that is disposed coaxially with the exhaust turbine 21. The intake pipe 24, the compressor 22, and the intake manifold 15 that introduces the intake air compressed by the rotational force of the exhaust turbine 21 into the combustion chamber 12.

When the internal combustion engine 1 is operated, unburned hydrocarbon (HC) leaks from the gap between the piston 11a and the cylinder 11c to the piston back side of the crankcase 11.
The leaked unburned hydrocarbon (HC) flows out into the rocker cover 13 through a blow-by gas discharge passage (not shown) provided in the crankcase 11.
The blow-by gas collected in the rocker cover 13 is sucked from an introduction portion 33 configured by a blow-by hose 3 that is a blow-by gas introduction member and a connector 31 that is disposed in the intake pipe 24 and connected to the blow-by hose 3. Introduced into the tube 24.

The introduction portion 33 is disposed in the intake pipe 24 upstream of the compressor 22 and close to the compressor 22.
The connector 31 is manufactured from a material having high thermal conductivity because a heating pipe to be described later is attached.
In the present embodiment, a copper material having high thermal conductivity is used, but aluminum or the like may be used.

  Reference numeral 5 denotes a heating means. The heating means 5 is connected to a cooling system path for cooling the inside of the cylinder head of the crankcase 11 and the turbocharger 2, a first heating hose 51 for pumping the coolant R to the turbocharger 2, The second heating hose 52 connected to one of the U-shaped heating pipes 54 fixed to the connector 31, the heating pipe 54, the other of the heating pipes 54, and the water pump 63 of the crankcase 11 (see FIG. 2), the third heating hose 53 is connected.

FIG. 2 is a schematic configuration diagram of a cooling system in the embodiment of the internal combustion engine 1.
The internal combustion engine 1 includes a crankcase cooling unit 18 that cools the inside of the crankcase 11 and a cylinder head cooling unit 19 that cools the inside of the cylinder head 16 disposed at the upper part of the crankcase 11.

The flow path of the coolant R when the coolant R that cools the engine 1 has not reached the specified temperature in a state where the engine 1 has been started will be described.
The water pump 63 is driven in conjunction with the rotation of the crankshaft 11b of the internal combustion engine 1.
The coolant R circulates in the crankcase cooling unit 18 by driving the water pump 63 to cool the crankcase 11.
The coolant R circulated in the crankcase cooling unit 18 is pumped from the coolant outlet 18a to the cylinder head cooling unit 19.
The coolant R circulates in the cylinder head cooling unit 19 to cool the cylinder head 16.
In this case, since the temperature of the coolant R does not reach the specified temperature, the thermostat 62 is closed on the first inlet 62a side and the second inlet 62b is opened.
Accordingly, the main flow of the coolant R flows from the radiator side outlet 19a to the second inlet 62b side of the thermostat 62 (dotted line), and flows from the outlet 62c to the water pump 63 side.

On the other hand, in the case of blow-by gas heating by the coolant R, a part of the coolant R that has cooled the inside of the cylinder head cooling unit 19 is supplied from the blow-by gas heating side outlet 19b of the cylinder head cooling unit 19 to the first heating hose 51. To the turbocharger 2 side.
The exhaust turbine 21 of the turbocharger 2 is exposed to high-temperature exhaust gas.
Accordingly, the coolant temperature of the coolant R further rises by cooling the turbocharger 2.
The coolant R that has cooled the turbocharger 2 flows into the heating pipe 54 through the second heating hose 52.
The heating pipe 54 is made of a copper material, and can efficiently conduct heat to the connector 31 made of the same copper material.
The coolant R exchanged heat with the connector 31 by the heating pipe 54 returns to the water pump 63 disposed in the crankcase 11 via the third heating hose 53.

When the warm-up operation of the internal combustion engine 1 is finished and the temperature of the coolant R becomes equal to or higher than a specified value, the second inlet 62b side of the thermostat 62 is closed and the first inlet 62a side is opened.
Therefore, the coolant R pumped by the water pump 63 flows in the order of the crankcase cooling section 18 → the cylinder head cooling section 19, and from the radiator side outlet 19a, the first radiator hose 61a → the radiator 61 → the second radiator hose 61b. And flows to the water pump 63 side through the first inlet 62a of the thermostat 62.
The flow path of the cooling liquid R on the blow-by gas heating device side is the same as that when the temperature of the cooling liquid R is equal to or lower than a specified value, and is omitted.
Reference numeral 65 denotes a reservoir tank.
When the cooling water R expands due to heat, the reservoir tank 65 stores (releases) the cooling liquid R in the reservoir tank 65 via the pressure adjustment cap 64, and when the cooling liquid R cools and the volume contracts, It has the effect of replenishing the cooling system path with the coolant R of the reservoir tank 65 via the pressure adjustment cap 64.

FIG. 3A is a partially enlarged view of FIG. 2Z, and FIG. 3B is a view taken in the direction of arrow Y in FIG.
The connector 31 is made of a copper material as described above.
The connector 31 is fixed with a heating pipe 54 made of the same copper material and formed in a U-shape.
The U-shaped bottom portion is formed so as to come into contact (line contact) with the outer periphery of the connector 31.
V-shaped gaps W on both sides (in the axial direction of the connector 31) of the heating pipe 54 at the contact portion (line contact) between the outer periphery of the connector 31 and the heating pipe 54 are brazed.
The brazing was in the L range described in FIG.
Also, the reason why the outer periphery of the connector 31 and the contact portion between the heating pipe 54 are brazed is that the brazing material has high penetration into the contact portion, and the contact area between the outer periphery of the connector 31 and the heating pipe 54 is large. It is to increase the amount of heat conduction.
This is to increase the amount of heat exchange by increasing the contact area between the heating pipe 54 and the connector 31.

FIG. 4 shows a modification of the connector. A groove 35 a having a semicircular cross section is formed in the circumferential direction on the outer peripheral portion of the connector 35 with substantially the same curvature as the outer shape of the heating pipe 54.
Although not shown, in this case as well, a V-shaped gap W formed at the contact portion between the heating pipe 54 and the connector 35 is brazed.
This is because the contact area between the heating pipe 54 and the connector 35 is further increased to increase the amount of heat exchange.

FIG. 5A is a detailed view of the connector mounting portion, FIG. 5B is a view taken in the direction of the arrow X in FIG. 6A, and FIG.
The conventional connector 38 is disposed in the intake pipe 24 at a position away from the compressor 21 on the upstream side of the intake system path of the compressor 21 of the turbocharger 2.
Further, the blow-by hose 3 is connected to an L-shaped connector 38.
As shown in FIG. 1, the blow-by hose 3 is routed from the right side to the left side of the internal combustion engine 1 in the state of FIG.
The turbocharger 2 mounted on the exhaust manifold 14 is disposed on the left side of the internal combustion engine 1, and a cooling pipe for cooling the turbocharger 2 is disposed.
Accordingly, the blow-by hose 3 is unavoidably arranged in consideration of restrictions on the vehicle.

As described above, blow-by gas contains a lot of moisture. When blow-by gas flows through the bent portion, the flow velocity changes between the inside and the outside of the bent portion, and the contained moisture collides with each other and condenses to become water droplets.
Further, when the length of the blow-by hose 3 from the rocker cover 13 to the intake pipe 24 is increased, cooling of the blow-by gas proceeds in a very cold region.
Moreover, in the extremely cold region, it freezes in a water vapor state, and each fine grain grows while the frozen grains are bonded to each other.
Accordingly, the water droplets in the blow-by hose 3 freeze and grow rapidly.
In particular, since the connector 38 has an L shape, condensed water tends to accumulate in the connector 38 and freezes.

FIG. 5A is a detailed shape diagram of the attachment portion of the connector in the present embodiment, showing a plan view when mounted on the vehicle, and FIG. 5B is a view taken in the direction of arrow X in FIG.
As can also be determined from FIGS. 5A and 5B, the blow-by hose 3 has a wiring structure that extends substantially linearly to the vicinity of the turbocharger 2 and is bent obliquely downward.
A connector 31 to which the blow-by hose 3 is connected is formed in a straight line and disposed in the intake pipe 24 near the inlet of the compressor 22 of the turbocharger 2.
By making the connector 31 linear, the overall shape of the connector 31 is made compact and a space for fixing the heating pipe 54 can be secured.

With such a structure, a part of the coolant R that has cooled the internal combustion engine 1 is diverted, the turbocharger 2 is cooled, and the blow-by hose 3 is cooled by the coolant R that is further heated by the turbocharger. Since the connector 31 with the intake pipe 24 is heated, the frozen condensed water R in the connector 31 can be melted and the blow-by hose can be effectively prevented from being blocked by freezing.
Furthermore, since the structure is such that the coolant of the internal combustion engine is divided as a heat source for preventing freezing, the cost can be reduced.

  It is a pipe line for introducing blow-by gas of an internal combustion engine into an intake system passage, and can be used for a blow-by gas reduction device that prevents water contained in blow-by gas from freezing.

1 Internal combustion engine 2 Turbocharger 3 Blow-by hose (Blow-by gas introduction member)
DESCRIPTION OF SYMBOLS 5 Heating means 11 Crankcase 12 Combustion chamber 13 Rocker cover 14 Exhaust manifold 15 Intake manifold 16 Cylinder head 21 Exhaust turbine 22 Compressor 23 Air cleaner 24 Intake pipe 31, 35 Connector 33 Introduction part 51 1st heating hose (heating means)
52 Second heating hose (heating means)
53 3rd heating hose (heating means)
54 Heating pipe (heating means)
63 Waterpump

Claims (5)

A blow-by gas reduction device for reducing blow-by gas leaked into a crankcase of an internal combustion engine to an intake pipe of an intake system path,
A turbocharger that is driven by exhaust gas discharged from the internal combustion engine and compresses intake air to supercharge the internal combustion engine;
A heating means for warming the blow-by gas with the cooling liquid returning to the water pump of the internal combustion engine after cooling the turbocharger by diverting a cooling liquid for cooling the internal combustion engine from the internal combustion engine;
A blowby gas introduction member for introducing the blowby gas into the intake pipe on the upstream side of the compressor of the turbocharger,
The condensate frozen inside the introduction part is melted by heating the introduction part where the blow-by gas introduction member and the intake pipe are connected by the heating means. Blow-by gas reduction device.   The blow-by gas reduction device according to claim 1, wherein the introduction portion includes a connector fixed to an intake pipe and connected to the blow-by gas introduction member, and the connector is made of a copper material.   3. The blow-by gas reduction device according to claim 1, wherein the introduction portion is disposed in the intake pipe in the vicinity of a connection portion between the intake pipe and the compressor.   The blow-by gas reduction device according to any one of claims 1 to 3, wherein the connector is formed in a straight line.   5. The groove according to claim 1, wherein a concave groove having substantially the same curvature as the outer peripheral portion of the axial cross-sectional shape of the cooling member is formed along the circumferential direction on the outer peripheral surface of the connector. The blowby gas reduction apparatus as described.

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