JP5159550B2 - Blowby gas recirculation device for internal combustion engine - Google Patents

Description

  The present invention relates to a blow-by gas recirculation device for an internal combustion engine that separates oil in the blow-by gas in the crank room of the internal combustion engine and recirculates it to intake air.

  In an internal combustion engine, the blow-by gas in the crank room is returned to the intake system for processing, and an oil separator (gas-liquid separation chamber) is provided in the blow-by gas passage in order to separate and remove the oil content in the blow-by gas in advance. This has been known for some time. Further, there is known a blow-by gas passage disposed on a side surface of a cylinder block and provided with an oil separator chamber in the middle thereof (see, for example, Patent Document 1).

  In addition, fresh air is introduced into the crankcase from the upstream side of the intake system throttle valve, and blowby gas in the crankcase is passed downstream of the intake system throttle valve through a blowby gas passage provided in the cylinder block, cylinder head, and head cover. There is also known a PCV (Positive Crankroom Ventilation) type blow-by gas recirculation device which is recirculated to the side.

  As shown in FIG. 8, as the PCV type supply gas recirculation device, fresh air 63 (shown by a broken line) taken in on the upstream side of the throttle valve 62 of the intake system 61 is transferred from the head cover 64 to the cam chamber and cylinder of the cylinder head 65. The blow-by gas 70 is introduced into the crank room 68 through an oil drain hole 67 provided in the block 66, and the blow-by gas 70 in the crank room 68 passes through the cylinder block 66 and the cylinder head 65 as shown by the solid arrows, and the cylinder in the middle thereof. Through the blow-by gas passage 71 provided with the oil separator chamber 72 on the side surface of the block 66 and the blow-by gas passage 73 provided in the head cover 64, the refrigerant flows back to the downstream side of the throttle valve 62 of the intake system 61 via the PCV valve 74. A configuration that could be .

Also, the chain cover is provided with a mounting portion for mounting on the inertia main shaft of the engine mount device, a breather chamber for separating oil from blowby gas is provided in the interior space, and blow-by is blown into the breather chamber through the blow-by gas passage in the chain cover. There has been known one in which space is effectively used by introducing gas (see, for example, Patent Document 2).
JP 2006-9647 A Japanese Patent Laid-Open No. 10-47157

  However, in the configuration as shown in FIG. 8, the blowby gas 70 enters the chain cover 75 from the crankroom 68 to generate a blowby gas reservoir 76 as shown surrounded by a virtual line, and a part thereof. Flows into the cam chamber of the cylinder head 65 and mixes with the fresh air 63 flowing into the crank room 68 through the oil drain hole 67 from the cam chamber, and therefore there is a problem that the blow-by gas 70 cannot be efficiently ventilated. In addition, the blow-by gas 70 stays in the chain cover 75 and the oil adheres as oil droplets, or a part of the staying blow-by gas 70 enters the cam chamber and is vigorously stirred at a high temperature. The oil separator and the white turbidity easily occur, and the oil separator on the side of the cylinder block 66 72 is configured by closing the opening of the concave portion formed on the side surface of the cylinder block 66 with a cover plate, and it takes time for assembly to seal the joint portion of the cover plate, and from the joint portion to the outside. There is a problem that may cause oil leakage.

  On the other hand, the configuration disclosed in Patent Document 2 merely recirculates the blow-by gas in the crank room to the intake system directly through the blow-by gas passage and the breather chamber in the chain cover, and the stay of the blow-by gas in the chain cover. However, this does not suggest a solution to the problem of efficiently ventilating the blow-by gas in the crankroom.

  In view of the above-described conventional problems, the present invention allows the flow of fresh air and blow-by gas introduced by the PCV method to be unidirectional, so that the fresh air and blow-by gas can be ventilated without being mixed and the blow-by gas An object of the present invention is to provide a blow-by gas recirculation device for an internal combustion engine that can prevent stagnation in the chain cover, improve the ventilation performance in the internal combustion engine, and suppress the occurrence of oil deterioration and white turbidity.

The blow-by gas recirculation device for an internal combustion engine according to the present invention has a first blow-by having an outlet to the intake system as one end on the front end side of the head cover and an inlet from the crank room as the other end on the rear side of the head cover. the gas passage is independent of the cam chamber which opens into the cylinder head provided in the head cover, the first communication passage to the cylinder block and the cylinder communicating with the other end of the first blow-by gas passage from inside the crank room provided through the head, it communicates with the one end the crank room, providing the second blow-by gas passage and the other end portion is connected to one end of the first blow-by gas passage in the chain cover, the fresh air is independent of the first blow-by gas passage fresh air passage for supplying the cam chamber provided in the head cover, the cam chamber fresh air Al wherein the second said first communication path a communication path leading to the crank room independently provided in the cylinder block, an oil separator in the middle portion of the first blow-by gas passage and the second blow-by gas passage It is provided .

  According to this configuration, fresh air introduced by the PCV method enters the cam chamber through the fresh air passage provided in the head cover, enters the crank room through the second communication passage provided in the cylinder block, The blow-by gas inside passes through the first communication passage provided through the cylinder block and the cylinder head and the first blow-by gas passage provided in the head cover, and reaches the outlet to the intake system at one end thereof. , And the second passage through the second blow-by gas passage provided in the chain cover to the first blow-by gas passage, the refrigerant is recirculated to the intake system. As a result, the fresh air and the blow-by gas can be ventilated without being mixed in the middle, and the second path of the blow-by gas passes through the chain cover. -Blow-by gas can be prevented from staying in the chamber and the blow-by gas does not pass through the cam chamber, so that the ventilation performance in the internal combustion engine can be improved and the deterioration of oil and cloudiness can be suppressed. Since the oil separator portion is not provided on the side surface, the number of assembling steps can be reduced, the cost can be reduced, and the risk of oil leakage from the oil separator portion can be eliminated.

The first blow-by gas passage has an oil separator between one end and the other end, and the second blow-by gas passage is disposed in a recessed space on the back side of the engine mount portion of the chain cover. When the oil separator box is configured to include the oil separator box in the middle and the connection duct extending from the oil separator box is connected to one end of the first blow-by gas passage, the blow-by gas passing through the first path is The blow-by gas passing through the second path can be separated into gas and liquid in the oil separator box disposed in the recessed space on the back side of the engine mount part of the chain cover, and passes through both paths. Blow-by gas oil can be reliably separated and removed, and the back side of the engine mount Space can be effectively utilized to space-saving.

  According to the blow-by gas recirculation device for an internal combustion engine of the present invention, fresh air flows into the crank room through a path independent of the blow-by gas path, and the blow-by gas in the crank room passes through the cylinder block and the cylinder head. Since it is recirculated to the intake system through both the first path passing through the first blow-by gas passage provided in the head cover and the second path passing through the second blow-by gas path provided in the chain cover, The flow of fresh air and blow-by gas can be unidirectional to ventilate the fresh air and blow-by gas without being mixed in the middle, and it is possible to prevent the blow-by gas from staying in the chain cover, and the blow-by gas can enter the cam chamber. Since it does not pass, the ventilation performance in the internal combustion engine can be improved and the occurrence of oil deterioration and cloudiness can be suppressed. Since not provided an oil separator portion on the side surface of the lock, it is possible to achieve a cost reduction by can reduce the assembly man-hours, the risk of oil leakage from the oil separator unit can also be eliminated.

  Hereinafter, an embodiment of a blow-by gas recirculation device for an internal combustion engine of the present invention will be described with reference to FIGS.

  In FIG. 1, reference numeral 1 denotes an internal combustion engine, in which a plurality of cylinders are arranged in parallel at the top, a cylinder block 2 that forms the top of the crankroom 7 at the bottom, and a cylinder block 2 that corresponds to each cylinder at the bottom. The combustion chamber to be operated has a cylinder head 3 with a cam chamber formed in the upper part thereof, and a chain cover 4 disposed on the front surface of the cylinder block 2 and the cylinder head 3, that is, on the end surface on the side where the timing chain and auxiliary equipment are disposed. And an oil pan 6 which is disposed above the cylinder head 3 and the chain cover 4 and covers the upper part of the cam chamber, and an oil pan 6 which is disposed below the cylinder block 2 and forms the oil reservoir 6a with the lower part of the crankroom 7. It is composed of.

  The internal combustion engine 1 includes an intake system 8 that supplies intake air to each combustion chamber of the cylinder head 3 and an exhaust system (not shown) that exhausts exhaust gas. The intake system 8 passes outside air through an air cleaner 9. The intake amount is controlled by the intake valve 10 and supplied to each combustion chamber via the intake manifold and the intake valve. On the other hand, with the operation of the internal combustion engine 1, part of the combustion gas leaks into the crankroom 7 to generate blowby gas 11, and a blowby gas retention region 12 is formed in the crankroom 7.

  A PCV type blow-by gas recirculation device 13 for introducing fresh air from the intake system 8 into the blow-by gas retention region 12 and forcing the blow-by gas 11 out of the crank room 7 to return to the intake system 8 is provided. The blow-by gas recirculation device 13 passes the fresh air 15 taken out from a fresh air outlet 14a provided upstream of the throttle valve 10 of the intake system 8 through a fresh air supply pipe 14 and a fresh air introduction path 16 indicated by a broken arrow. The blow-by gas 11 is introduced toward the blow-by gas retention region 12 in the crank room 7, and the blow-by gas 11 in the blow-by gas retention region 12 reaches the PCV valve 18 disposed in the head cover 5 through the blow-by gas recirculation path 17 indicated by a solid arrow. The flow rate is controlled by the PCV valve 18 and is mixed into the intake air through a blow-by gas pipe 19 through a blow-by gas inlet 19a provided downstream of the throttle valve 10 of the intake system 8.

  The fresh air introduction path 16 communicates between a fresh air inlet 21 provided on the upper surface of the head cover 5 and an outlet opening 23 provided on the lower surface of the head cover 5, and introduces fresh air into the cam chamber of the cylinder head 3. A fresh air passage 22 and a second communication passage 24 that introduces fresh air into the crankroom 7 from the cam chamber of the cylinder head 3 through the cylinder block 2 are configured. Specifically, the second communication passage 24 also serves as an oil drain hole formed in the cylinder block 2 in order to return oil from the cylinder head 3 to the oil pan 6.

  The blow-by gas recirculation path 17 communicates between the PCV valve 18 serving as an outlet disposed on the upper surface of the head cover 5 and a first inlet 27 provided on the lower surface of the head cover 5, and an oil separator portion 26 therebetween. The first blow-by gas passage 25 having the first blow-by gas passage and the first blow-by gas passage 25 provided through the cylinder head 2 and the cylinder block 3 so as to communicate between the inlet 27 and the crankroom 7. A chain cover between the first communication passage 28 and the second blow-in gas passage 25 in the vicinity of the PCV valve 18 in the vicinity of the PCV valve 18 and the second inlet 29 provided in the lower surface of the head cover 5 and the inside of the crankroom 7. 4 is constituted by a second blow-by gas passage 30 in which an oil separator box 31 is disposed therebetween. The first communication passage 28 through which blow-by gas flows and the second communication passage 24 through which fresh air flows are formed independently of each other, and the first blow-by gas passage 25 is formed in the cylinder head 3. The cam chamber and the fresh air passage 22 are formed independently.

  Next, specific configurations of the fresh air introduction path 16 and the blow-by gas recirculation path 17 will be described with reference to FIGS. As shown in FIGS. 2A and 2B, the head cover 5 is provided with a cam chamber forming space 32 that forms a cam chamber with the upper portion of the cylinder head 3. A spark plug placement space 33 is provided in which a spark plug mounted in the combustion chamber of the cylinder is placed. The periphery of the spark plug placement space 33 protrudes upward, and the fresh air passage 22 and the first blow-by gas passage 25 are configured by partitioning the protrusion space and the cam chamber forming space 32 by a partition plate 34. . That is, the lower part of the peripheral side wall of the fresh air passage 22 and the first blow-by gas passage 25 is suspended, and the lower end thereof and the partition plate 34 are joined by welding or the like as shown by the oblique lines in FIG. ing. The fresh air passage 22 and the first blow-by gas passage 25 are separated from each other by partition walls 35a and 35b and are formed independently of each other.

  The fresh air inlet 21 at one end of the fresh air passage 22 is disposed at one side near the rear portion of the head cover 5, and is located at the other side of the front portion of the head cover 5 from the other end of the fresh air passage 22 to the head cover 5. A first connecting cylinder portion 36 extending to the lower end is provided, and the lower end opening forms an outlet opening 23 of the fresh air passage 22 so that fresh air is supplied into the cam chamber. Further, as shown in FIG. 2A and FIG. 3, the second connecting cylinder portion extending from the other end portion of the first blowby gas passage 25 to the lower end of the head cover 5 at the other side position near the rear portion of the head cover 5. 37 is provided, the lower end opening of which constitutes the first inlet 27 of the first blow-by gas passage 25 and is connected to the first communication passage 28 formed through the cylinder block 2 and the cylinder head 3. ing.

  The oil separator portion 26 provided in the intermediate portion of the first blow-by gas passage 25 has a zigzag flow path formed by a plurality of baffle plates 38 protruding alternately from both side walls of the first blow-by gas passage 25. By forming and forming an orifice part between the front end and the side wall of each baffle plate 38, it has a gas-liquid separating action.

  As shown in FIGS. 2A and 4, a third connecting cylinder portion 39 extending from the vicinity of one end portion of the first blow-by gas passage 25 to the lower end of the head cover 5 is provided at a position near one side of the front end of the head cover 5. The lower end opening of the first blow-by gas passage 25 constitutes the second inlet 29 of the first blow-by gas passage 25 and is connected to the second blow-by gas passage 30 passing through the chain cover 4. A baffle plate 38a is projected from the partition plate 34 in an L-shape in plan view at a position before the blow-by gas flowing in from the second inlet 29 joins the blow-by gas that has flowed through the first blow-by gas passage 25. Further, a baffle plate 38b is also provided so as to cross the first blow-by gas passage 25 at a position before the PCV valve 18.

  As shown in FIGS. 4 and 5, the upper part of the second blow-by gas passage 30 is an oil separator box 31 disposed in a recessed space 41 on the back side of the engine mount portion 40 provided in the chain cover 4. The upper end opening 42 a of the connection duct 42 configured and extending upward from the oil separator box 31 is connected to the second inflow port 29. The oil separator box 31 is formed of a synthetic resin molded product, and as shown in FIGS. 6 and 7, the front view is a substantially inverted trapezoidal shape and protrudes forward so as to fit into the recessed space 41. The inlet 43 is formed in the lower part, and the outlet 44 from which the connection duct 42 is extended is provided in the upper surface. An inverted mountain-shaped baffle plate 45 is arranged in the oil separator box 31 so as to face the inlet 43 so as to cross back and forth, and a labyrinth portion is formed on both sides of the baffle plate 45 so as to exert a gas-liquid separation action. It is configured. 46 is an oil escape hole.

  The oil separator box 31 has mounting pieces 47a, 47b, 47c projecting from both sides of the upper end portion and the lower end portion thereof, and projecting from the inner surface of the chain cover 4 by mounting bolts 50 passed through the bolt holes 48 at the tip end portion. The mounting boss 49 is fastened and fixed. 4 and 5, 51 is a camshaft, 52 is a cam sprocket fixed to the front end of the camshaft 51, and 53 is a crank sprocket (not shown) fixed to the front end of the crankshaft and the cam sprocket 52. It is a timing chain wrapped around. .

  In the blow-by gas recirculation device 13 of the internal combustion engine 1 having the above-described configuration, the fresh air 15 taken out at the upstream position of the throttle valve 10 of the intake system 8 passes through the fresh air passage 22 provided in the head cover 5 to the cylinder head. 3 enters the crank room 7 through the second communication path 24 formed by an oil dropping hole provided in the cylinder block 2. On the other hand, the blow-by gas 11 in the blow-by gas staying region 12 in the crank room 7 is a first blow-by gas provided in the first communication passage 28 provided through the cylinder block 2 and the cylinder head 3 and the head cover 5. The first blow-by gas passage 25 passes through the passage 25 to the PCV valve 18 at the outlet disposed at one end thereof, and passes through the second blow-by gas passage 30 provided in the other chain cover 4. Are combined in the vicinity of the PCV valve 18, and returned to the downstream position of the throttle valve 10 of the intake system 8 from the PCV valve 18 through the blow-bypipe gas pipe 19.

  Therefore, the flow of the fresh air 15 and the blow-by gas 11 becomes one direction, and the fresh air 15 and the blow-by gas 11 can be efficiently ventilated by the PCV method without being mixed in the middle. Further, the blow-by gas 11 can be prevented from staying in the chain cover 4 by passing through the second blow-by gas passage 30 set in the chain cover 4, and the ventilation performance in the internal combustion engine 1 is improved. In addition, since the blow-by gas 11 does not pass through the cam chamber, it is possible to suppress oil deterioration and white turbidity. Further, as in the conventional example, only the first communication passage 28 is provided on the side surface of the cylinder block 2 and no oil separator portion is provided. Therefore, the number of assembling steps can be reduced and the cost can be reduced. There is an effect that it is possible to eliminate the risk of oil leakage from the tank.

  An oil separator portion 26 is provided in the first blow-by gas passage 25 disposed in the head cover 5, and a part of the second blow-by gas passage 30 passing through the chain cover 4 is connected to the engine mount portion of the chain cover 4. 40 is configured by an oil separator box 31 disposed in a recessed space 41 on the back surface side, and a connection duct 42 extending from the oil separator box 31 is connected to the first blow-by gas passage 25. The gas 11 passes through both the first blow-by gas passage 25 and the second blow-by gas passage 30, and the oil is gas-liquid separated in the oil separator portion 26 and the oil separator box 31, respectively. Oil can be separated and removed without fail, and the engine mount 4 Dead space on the back side of the can be effectively utilized to space the.

  Further, an oil separator box 31 made of a synthetic resin molded product is disposed in the recessed space 41 of the chain cover 4 to constitute a portion of the second blow-by gas passage 30 facing the cylinder head 2 and the cylinder head 3. Therefore, the passage of the blow-by gas 11 has a two-layer structure having a synthetic resin layer, so that the heat insulation effect is exhibited and deterioration of oil separated from the blow-by gas 11 can be further suppressed.

  The blow-by gas recirculation device according to the present invention allows the flow of fresh air and blow-by gas to be unidirectional so that the fresh air and blow-by gas can be ventilated without being mixed, and the blow-by gas stays in the chain cover. It can be prevented and blow-by gas does not pass through the cam chamber, so it can improve ventilation performance in the internal combustion engine and suppress oil degradation and white turbidity, making it suitable for blow-by gas recirculation devices for various internal combustion engines it can.

The schematic block diagram of one Embodiment of the blowby gas recirculation apparatus of the internal combustion engine of this invention. The head cover of the embodiment is shown, (a) is a bottom view, (b) is an AA arrow sectional view of (a). The longitudinal section of the blowby gas passage which penetrates the cylinder block and cylinder head of the embodiment. The longitudinal cross-sectional view of the blow-by gas passage which passes along the chain cover of the embodiment. The rear view of the chain cover which shows the arrangement | positioning state of the oil separator box of the embodiment. The oil separator box of the embodiment is shown, (a) is a front view, (b) is a side view. The longitudinal cross-sectional view which shows the internal structure of the oil separator box of the embodiment. The schematic block diagram of the blowby gas recirculation apparatus of the internal combustion engine of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder block 3 Cylinder head 4 Chain cover 5 Head cover 7 Crankroom 8 Intake system 11 Blow-by gas 13 Blow-by gas recirculation device 15 Fresh air 18 PCV valve (outlet)
22 Fresh air passage 24 Second communication passage (oil pit)
25 First blow-by gas passage 26 Oil separator portion 28 First communication passage 30 Second blow-by gas passage 31 Oil separator box 40 Engine mount portion 41 Recessed space 42 Connection duct

Claims (2)

A cam chamber in which a first blow-by gas passage having an outlet to the intake system as one end on the front end side of the head cover and an inflow port from the crank room as the other end on the rear side of the head cover is opened in the cylinder head. Is provided on the head cover independently of the
It provided a first communication path that communicates with the other end of the first blow-by gas passage from inside the crank room through the cylinder block and the cylinder head,
Communicating one end in the crank room, providing the second blow-by gas passage and the other end portion is connected to one end of the first blow-by gas passage in the chain cover,
The fresh air passage for supplying fresh air into the cam chamber is independent of the first blow-by gas passage provided in the head cover,
Fresh air and a second said first communication path a communicating passage leading from the cam chamber into the crank room independently provided in the cylinder block,
A blow-by gas recirculation device for an internal combustion engine, wherein an oil separator is provided in the middle of the first blow-by gas passage and the second blow-by gas passage . The oil separator provided in the middle portion of the second blow-by gas passage is configured to configure Te in arranged oil separator box to the rear surface side recessed space of the engine mount portion of the chain cover from the oil separator box The blow-by gas recirculation device for an internal combustion engine according to claim 1, wherein the extended connection duct is connected to one end of the first blow-by gas passage.

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