JP2017193963A - Blow-by gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow-by gas recirculation device mountable without changing the physical constitution of an engine, capable of reflection to an existing engine, and capable of avoiding the output decline of the engine by suppressing oil vaporization and deposit accumulation in a compressor.SOLUTION: The blow-by gas recirculation device is provided for the internal combustion engine equipped with a turbocharger 21 including a turbine 27 provided in an exhaust passage 26, and a compressor 22 provided in an intake passage 20 and adapted to be driven by the turbine 27. A PCV pathway 31 for guiding to the intake passage 20 blow-by gas subjected to oil separating action in a head cover 19 by an oil separator has such a shape as to cause a swirl flow in the blow-by gas flowing into the PCV pathway 31.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blow-by gas recirculation device that recirculates blow-by gas leaked into a crank chamber to an intake passage.

  Diesel engines are equipped with turbochargers (superchargers) to improve performance. A turbocharger is composed of a pair of a turbine and a compressor. In the turbocharger, the turbine rotates using the exhaust energy of the engine, and the compressor is driven coaxially. The compressor is arranged downstream of the air cleaner from the air cleaner, sucks and compresses the outside air, and supplies it to the engine cylinder. A PCV (positive crankcase ventilation) path is installed between the compressor and the air cleaner, and gas containing oil mist is circulated from the engine. A problem with this PCV path is that the oil mist that has been refluxed deposits in the compressor and closes the compressor path, thereby reducing supercharging efficiency and worsening fuel consumption and exhaust.

  Conventionally, a blow-by gas recirculation device having a plurality of oil separators for separating oil from blow-by gas is known. In Patent Document 1, a first oil separator is provided on the side surface of the cylinder block, and a second oil separator is provided in a space surrounded by the upper surface of the cylinder head and the cylinder head cover. A blow-by gas recirculation device has been proposed in which the first and second oil separators are communicated with each other through a communication path, and the entire communication path is formed inside the cylinder block and the cylinder head. The blow-by gas recirculation device is intended to suppress freezing of moisture contained in the blow-by gas in a communication path that connects the first oil separator and the second oil separator.

JP 2014-101866 A

  Patent Document 1 has no description regarding avoiding or suppressing the oil mist that has been refluxed through the PCV passage from being deposited and deposited in the compressor. As means for avoiding deposit accumulation in the compressor, there are (1) a decrease in the compressor surface temperature, (2) a reduction in the amount of PCV oil mist, and (3) a reduction in suit in the oil.

  However, the decrease in the compressor surface temperature of (1) is accompanied by a decrease in engine output, so that the commercial value of the engine is lowered. The reduction in the amount of PCV oil mist (2) is accompanied by an increase in the PCV (built into the head cover in many engines) capacity, making the engine taller and difficult to mount. In addition, (3) reducing suit in oil requires improvement of combustion, etc., and it is necessary to clarify the combustion phenomenon (an unexplained field with the current technology). For this reason, means for reducing the amount of oil mist without changing the current temperature conditions and engine layout is effective in reducing the deposit accumulation of the compressor.

  The present invention has been made in view of such circumstances, the purpose of which can be installed without changing the engine physique, can be reflected in the existing engine, suppresses oil evaporation and deposit accumulation in the compressor, An object of the present invention is to provide a blow-by gas recirculation device that can avoid a reduction in engine output.

  A blow-by gas recirculation device that solves the above problem is a blow-by gas recirculation device for an internal combustion engine that includes a turbocharger that includes a turbine provided in an exhaust passage and a compressor provided in an intake passage and driven by the turbine. Thus, the shape of the PCV path that guides the blow-by gas that has been subjected to the oil separating action by the oil separator in the head cover to the intake passage is made to generate a swirling flow in the blow-by gas that flows into the PCV path.

  According to this configuration, when blow-by gas flows from the inlet of the PCV path into the PCV path in a state including oil mist, the blow-by gas becomes a swirling flow and travels in the PCV path toward the outlet. When the blow-by gas is swirled and travels through the PCV path, the oil mist contained in the blow-by gas is separated from the blow-by gas and adheres as droplets to the wall surface of the PCV path. Therefore, the amount of oil mist carried by blow-by gas to the compressor is reduced, and deposit accumulation in the compressor is suppressed.

  The PCV path has a portion in which the inner diameter gradually decreases from the inlet side toward the outlet side, and the blow-by gas inlet is provided so that the blow-by gas flows obliquely into the PCV path. According to this configuration, it is possible to easily form a configuration in which the blow-by gas that has flowed into the PCV path from the inlet of the PCV path becomes a swirling flow.

  The PCV path is provided such that the entrance side is lower than the exit side. According to this configuration, the oil dropletized in the PCV path flows back into the head cover while the engine is stopped, and the oil is refluxed into the cylinder head. As a result, the oil consumption of the engine can be reduced.

  According to the present invention, it can be installed without changing the engine size, can be reflected in an existing engine, can suppress oil evaporation and deposit accumulation in the compressor, and can avoid a decrease in engine output. .

Schematic which shows the whole structure of a blowby gas recirculation apparatus. The model exploded perspective view which shows the relationship between a head cover, PCV hose, and a compressor inlet pipe. The schematic diagram which shows the state of the gas in a PCV hose. The model exploded perspective view of another embodiment.

Hereinafter, an embodiment of a blow-by gas recirculation device in a diesel engine embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the engine 10 includes an oil pan 11 that stores engine oil O, a cylinder block 12, and a cylinder head 13. A crankcase (crank chamber) 14 is formed by the oil pan 11 and the cylinder block 12. A piston 15 is accommodated in a cylinder bore provided in the cylinder block 12.

  A combustion chamber 16 is formed above the piston 15 of the cylinder block 12. An intake port 17 and an exhaust port 18 communicating with the combustion chamber 16 are formed in the cylinder head 13. The intake port 17 is opened and closed by an intake valve (not shown). The exhaust port 18 is opened and closed by an exhaust valve (not shown). A fuel injection valve (not shown) is provided in the cylinder head 13.

A head cover 19 that covers the cylinder head 13 is provided on the upper side of the cylinder head 13. An oil separator (not shown) is provided in the head cover 19.
The intake port 17 is connected to the compressor 22 of the turbocharger 21 via the intake passage 20. An intercooler 23 is provided in the intake passage 20. The compressor 22 takes in the outside air purified by the air cleaner 24 through the intake passage 20. The exhaust port 18 is connected to the turbine 27 of the turbocharger 21 via the exhaust passage 26, and the turbine 27 is driven by the exhaust energy of the engine 10. The rotation of the turbine 27 is transmitted to the compressor 22 through the shaft, and the compressor 22 rotates. The intake air is compressed by the rotation of the compressor 22 and the turbocharger 21 performs supercharging.

  The cylinder block 12 is provided with a blow-by gas discharge passage 30 for discharging blow-by gas leaking into the crankcase 14 from the gap between the cylinder block 12 and the piston 15. A plurality of blow-by gas discharge passages 30 are provided, and the plurality of blow-by gas discharge passages 30 merge in the head cover 19 and are supplied to the intake passage 20 via the PCV passage 31. The PCV path 31 is connected to the intake passage 20 between the air cleaner 24 and the compressor 22.

  More specifically, as shown in FIG. 2, the PCV path 31 is formed by a hose 32. The hose 32 is formed in a shape that causes a swirl flow in the blow-by gas that has flowed into the PCV path 31, that is, the hose 32, after being subjected to oil separation action by the oil separator in the head cover 19.

  In this embodiment, as shown in FIG. 3, the hose 32 has a portion in which the inner diameter gradually decreases from the inlet side toward the outlet side, and the blow-by gas inlet has the blow-by gas slanted into the hose 32. It is provided so that it may flow into. In FIG. 3, the flow of blow-by gas is shown by broken arrows.

  As shown in FIG. 2, the hose 32 is connected to the inlet side 32 a of the PCV path 31, that is, the side connected to the connecting portion 19 a that protrudes from the head cover 19, that is, the side connected to the compressor 22. In a lower state, the compressor 22 is connected to the connecting portion 33a of the compressor inlet pipe 33. That is, the PCV path 31 is provided such that the inlet side is lower than the outlet side.

Next, the operation of the blow-by gas recirculation device configured as described above will be described.
The turbocharger 21 rotates the turbine 27 using the energy of the exhaust gas discharged from the exhaust port 18 of the engine 10, and the compressor 22 is rotated by the rotation of the turbine 27. The intake air is compressed by the rotation of the compressor 22 and the turbocharger 21 performs supercharging.

  The blow-by gas that has entered the crankcase 14 from the gap between the piston 15 and the cylinder bore from the combustion chamber 16 flows into the head cover 19 through the blow-by gas discharge passage 30. And after a part of oil mist is isolate | separated by the oil separator provided in the head cover 19, it flows in the state which improved the flow velocity in the hose 32 which comprises the PCV path | route 31. FIG.

  When blow-by gas containing oil mist flows into the hose 32, it turns into a swirling flow and travels through the hose 32 toward the outlet. When the blow-by gas is swirled and travels through the hose 32, a part of the oil mist contained in the blow-by gas is separated from the blow-by gas and adheres as droplets to the wall surface of the hose 32. Therefore, the amount of oil mist conveyed by blow-by gas to the compressor 22 is reduced, and deposit accumulation in the compressor 22 is suppressed.

  Moreover, the improvement in the flow rate of blow-by gas increases the particle size of the oil mist, increases the heat capacity, and makes it difficult to evaporate. When blow-by gas flows into the PCV path 31 from the inlet of the PCV path 31 with the oil mist included, the blow-by gas turns into a swirling flow and travels through the PCV path 31 toward the outlet. When the blow-by gas is swirled and travels through the PCV path 31, part of the oil mist contained in the blow-by gas easily adheres as droplets to the inner wall surface of the hose 32. Further, when the flow rate of the blow-by gas is increased, the oil mist aggregates to be easily formed into droplets, and more easily adheres as droplets to the inner wall surface of the hose 32.

  The remaining oil mist that did not adhere to the wall surface of the hose 32 while passing through the hose 32 flows into the compressor 22 through the compressor inlet pipe 33 together with the blow-by gas. Since the blow-by gas increases in flow rate and flows into the compressor 22, the oil mist aggregates into droplets and adheres to the compressor 22. When oil mist becomes droplets, deposit accumulation in the compressor 22 is suppressed. In addition, the oil mist aggregates into droplets, which increases the heat capacity and makes it difficult to evaporate.

  During engine operation, since there is an intake gas flow in the hose 32 and the compressor 22, the oil mist that has been dropletized in the hose 32 and the compressor 22, that is, oil, flows on the surfaces of the compressor inlet pipe 33 and the compressor 22. It flows into the cylinder block 12. In addition, since the hose 32 is formed so that the inlet side 32a is lower than the outlet side 32b, the oil dropletized in the hose 32 flows back into the head cover 19 while the engine is stopped, and the oil flows into the cylinder head 13. To reflux.

According to this embodiment, the following effects can be obtained.
(1) The blow-by gas recirculation device is a blow-by gas recirculation of an internal combustion engine including a turbocharger 21 including a turbine 27 provided in the exhaust passage 26 and a compressor 22 provided in the intake passage 20 and driven by the turbine 27. Device. Then, the shape of the PCV path 31 that guides the blow-by gas that has been subjected to the oil separation action by the oil separator in the head cover 19 to the intake passage 20 is made to generate a swirling flow in the blow-by gas that flows into the PCV path 31.

  According to this configuration, when blow-by gas flows into the PCV path 31 from the inlet of the PCV path 31 while containing oil mist, the blow-by gas turns into a swirling flow and travels through the PCV path 31 toward the outlet. When the blow-by gas is swirled and travels through the PCV path 31, the oil mist contained in the blow-by gas is separated from the blow-by gas and adheres as droplets to the wall surface of the PCV path 31. Therefore, the amount of oil mist carried by blow-by gas to the compressor 22 is reduced, and deposit accumulation in the compressor 22 is suppressed.

  Further, since the hose 32 constituting the PCV path 31 has a larger area in contact with the outside air than in the head cover 19, the temperature is low, and the gas swirled in the hose 32 comes into contact with the wall surface to lower the gas temperature. Becomes easier to form droplets.

  (2) The hose 32 constituting the PCV path 31 has a portion in which the inner diameter gradually decreases from the inlet side 32 a toward the outlet side 32 b, and the blow-by gas inlet has the blow-by gas slanted into the PCV path 31. It is provided so that it may flow into. According to this configuration, it is possible to easily form a configuration in which the blow-by gas flowing into the PCV path 31 from the inlet of the PCV path 31 becomes a swirling flow.

  (3) As for the hose 32 which comprises the PCV path | route 31, the entrance side 32a is provided lower than the exit side 32b. According to this configuration, the oil dropletized in the PCV path 31 flows back into the head cover 19 while the engine is stopped, and causes the oil to flow back into the cylinder head 13. As a result, the oil consumption of the engine can be reduced.

The embodiment is not limited to the above, and may be embodied as follows, for example.
As shown in FIG. 3, the hose 32 constituting the PCV path 31 is not limited to a shape having an inner diameter that gradually decreases from the inlet side 32a toward the outlet side 32b. It is good also as a shape which reduces gradually toward the exit side 32b from the entrance side 32a.

The hose 32 is not limited to a circular cross section, and may be, for example, an oval or an oval (a shape in which a pair of arcs are connected by two straight lines).
The hose 32 constituting the PCV path 31 may be provided with the inlet side 32a at the same height as the outlet side 32b, or with the inlet side 32a higher than the outlet side 32b.

  The connecting part 19a connected to the inlet side 32a side of the hose 32 and the connecting part 33a connected to the outlet side 32b are not limited to the structure directly connected to the hose 32. For example, as shown in FIG. 19a and the connecting portion 33a may be connected to the hose 32 via connecting pipes 35a and 35b. In this case, it becomes easy to connect to the hose 32 having a different shape and size, and to adjust the angle at which blow-by gas flows into the hose 32 to an angle at which swirl flow is likely to occur.

  (Circle) You may apply not only to the blowby gas recirculation apparatus in a diesel engine but to the blowby gas recirculation apparatus in a gasoline engine. In a gasoline engine, a valve is provided to switch between using and not using the PCV route.

  DESCRIPTION OF SYMBOLS 19 ... Head cover, 20 ... Intake passage, 21 ... Turbocharger, 22 ... Compressor, 26 ... Exhaust passage, 27 ... Turbine, 31 ... PCV route, 32a ... Inlet side, 32b ... Outlet side

Claims (3)

A blow-by gas recirculation device for an internal combustion engine comprising a turbocharger comprising a turbine provided in an exhaust passage and a compressor provided in an intake passage and driven by the turbine,
A blow-by characterized in that the shape of the PCV path that guides the blow-by gas that has been subjected to oil separation action by the oil separator in the head cover to the intake passage is shaped to generate a swirling flow in the blow-by gas that flows into the PCV path. Gas reflux device.   The PCV path has a portion whose inner diameter gradually decreases from the inlet side toward the outlet side, and the blow-by gas inlet is provided so that the blow-by gas flows obliquely into the PCV path. Item 4. The blowby gas reflux device according to Item 1.   The blow-by gas recirculation device according to claim 1 or 2, wherein the PCV path is provided with an inlet side lower than an outlet side.

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