JP5806102B2 - 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.

  For example, as described in Patent Document 1, the internal combustion engine is provided with a return passage that connects the inside of the crankcase and the intake passage. The blow-by gas leaked from the combustion chamber into the crankcase through the gap between the piston and the cylinder is sucked through the recirculation passage and recirculated to the intake passage. In this way, ventilation in the crankcase is performed.

  By the way, the blow-by gas contains oil mist. If such oil mist is recirculated to the intake passage as it is, the oil may adhere to the inner wall of the intake passage and sludge may be generated.

  Therefore, in the technique described in Patent Document 1, an oil reservoir groove in which liquid oil is accumulated is provided in the middle of the reflux passage, and blow-by gas is allowed to pass through the liquid oil in the oil reservoir groove. Thereby, the oil mist contained in blow-by gas is made to adsorb | suck to liquid oil.

JP-A-5-39709

However, the technique described in Patent Document 1 has a problem that sludge is generated in the oil reservoir groove due to deterioration of the oil stored in the oil reservoir groove.
The present invention has been made in view of such circumstances, and the object thereof is to appropriately reduce oil mist contained in blow-by gas and to appropriately suppress the accumulation of sludge in the reflux passage. An object of the present invention is to provide a blow-by gas recirculation device for an internal combustion engine.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
(1) The invention according to claim 1 is a blow-by gas recirculation device for an internal combustion engine comprising a recirculation passage for recirculating blow-by gas in the crankcase to an intake passage of the internal combustion engine. 1 passage, a tank to which the other end of the first passage is connected, and a second passage for connecting the tank and the intake passage as the return passage, and an opening on the one end side of the first passage Is provided so as to be positioned vertically lower than the oil surface during the stop, which is the oil surface in the crankcase when the engine is stopped, and the return passage is caused by the negative pressure generated in the intake passage during engine operation. The oil in the crankcase is sucked into the tank through the first passage, and the oil level in the crankcase is lowered and the front of the first passage is reduced. That opening of the one end is configured to be exposed on the oil surface is the gist thereof.

  According to this configuration, when the engine is stopped, the opening portion of the first passage is immersed in the oil in the crankcase. When engine operation is started from this state, a negative pressure is generated in the intake passage and the negative pressure is introduced into the return passage. As a result, the pressure in the crankcase becomes higher than the pressure in the return passage so that the oil in the crankcase is sucked into the tank through the first passage and the oil level in the crankcase is lowered. Become. And the opening part of a 1st channel | path will be exposed on an oil surface in a crankcase. In such a state, the blow-by gas in the crankcase is returned to the intake passage through the return passage. Here, bubbling occurs when the blow-by gas passes through the liquid oil sucked into the tank and stored. As a result, oil mist contained in the blow-by gas, particularly oil mist having a small particle diameter, is adsorbed by the liquid oil.

  Further, according to such a configuration, when the engine operation is stopped and the negative pressure in the intake passage disappears, the oil sucked into the tank is returned to the crankcase through the first passage. For this reason, the oil in a tank will be replaced. Therefore, the oil in the tank can be prevented from deteriorating, and the generation of sludge in the tank can be suitably suppressed.

  Therefore, according to the present invention, the oil mist contained in the blow-by gas can be accurately reduced, and the accumulation of sludge in the reflux passage can be suitably suppressed.

  By the way, when the crankshaft rotates, the oil stored in the crankcase is agitated. Therefore, the higher the oil level, the more oil the crankshaft stirs and the greater the engine resistance that occurs when the crankshaft stirs the oil. In particular, when the internal combustion engine rotates at high speed, oil is frequently stirred by the crankshaft, and bubbles are mixed into the oil to raise the oil level, thereby further increasing the engine resistance.

  In this regard, according to the above-described configuration of the present invention, the oil level in the crankcase can be kept low during engine operation, so that less oil is stirred by the crankshaft. Therefore, the engine resistance generated when the crankshaft agitates the oil can be suitably reduced.

  (2) The invention according to claim 2 is the blowby gas recirculation device for the internal combustion engine according to claim 1, wherein the tank is provided outside the crankcase.

  When the tank is provided inside the crankcase, it is necessary to increase the size of the crankcase, and the design of the existing crankcase must be significantly changed. In this regard, according to the above configuration, since the tank is provided outside the crankcase, it is not necessary to increase the size of the crankcase. Therefore, the invention according to claim 1 can be embodied without greatly changing the design of the existing crankcase.

  (3) In the blow-by gas recirculation device for an internal combustion engine according to claim 1 or 2, the first passage has a connection portion connected to a lower end portion in the vertical direction of the tank, and the connection portion is The gist is that it is provided at the same position or above the oil surface at the time of stopping in the vertical direction.

  According to this configuration, when the engine operation is stopped and the negative pressure in the intake passage disappears, the oil sucked into the tank is returned to the crankcase through the first passage by its own weight, It becomes empty. For this reason, all the oil in the tank can be replaced each time the engine is stopped. Therefore, it is possible to accurately suppress the oil from adhering to the inner wall of the tank and deteriorating, and it is possible to suitably suppress the generation of sludge in the tank.

In addition, oil can be suitably prevented from leaking when the tank is replaced, and workability can be improved.
(4) The invention according to claim 4 is the blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 3, wherein an oil separator is provided in the middle of the second passage. The gist of this is.

  Components having a small particle size in the oil mist contained in the blow-by gas are accurately reduced by being adsorbed by the same liquid oil stored in the tank when passing through the tank. However, the blow-by gas that has passed through the liquid oil in the tank may contain oil mist having a large particle size.

  In this regard, according to the above configuration, when the blow-by gas that has passed through the tank passes through the oil separator provided in the middle of the second passage, a component having a large particle size is captured in the oil mist contained in the blow-by gas. Become so. Therefore, the oil mist contained in the blow-by gas returned to the intake passage can be accurately reduced regardless of the particle diameter.

  (5) According to a fourth aspect of the present invention, in the blow-by gas recirculation device for an internal combustion engine according to the fifth aspect, the oil separator is at least one of a labyrinth separator, a cyclone separator, and a filter separator. It can be materialized with the aspect of being. In this case, components having a large particle diameter can be suitably captured in the oil mist contained in the blowby gas.

  (6) The invention according to claim 6 is the blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 5, wherein the tank is made of a material having a lower density than oil. The gist is that the filter member is accommodated.

When bubbling bubbles bounce in the tank, oil mist having a large particle size may be newly generated.
In this regard, according to the above configuration, the filter member floats on the oil surface in the tank. For this reason, it is possible to suitably suppress the occurrence of oil mist having a large particle size when bubbling bubbles bounce.

  (7) The invention according to claim 7 is the blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 6, wherein fresh air is introduced into the crankcase from the intake passage. The gist of the invention is that a check valve for preventing the backflow of blow-by gas from the crankcase side to the intake passage side is provided in the introduction passage.

  According to this configuration, since the check valve is provided in the middle of the introduction passage, the blow-by gas in the crankcase is prevented from flowing back to the intake passage through the introduction passage. For this reason, the pressure in the crankcase is maintained high. Thereby, the oil in the crankcase is quickly sucked into the tank through the first passage. Therefore, the time required for the opening of the first passage to be exposed on the oil surface in the crankcase can be shortened.

  (8) The invention according to claim 8 is the blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 7, wherein one end of the first passage is in a horizontal direction in the crankcase. The gist is that the opening is close to the center position of.

  For example, when the opening on one end of the first passage is provided in the vicinity of the inner wall of the crankcase, depending on the position of the opening, too much oil in the crankcase is sucked through the first passage when the internal combustion engine is inclined. There is a risk of being. As a result, there is a shortage of oil in the crankcase, and the oil cannot be suitably sucked through the suction port of the oil strainer, and there is a risk that the oil supplied to the lubrication of each part of the engine will be short.

  In this regard, according to the above configuration, since one end of the first passage is opened close to the center position in the horizontal direction in the crankcase, the opening position on one end side of the first passage even when the internal combustion engine is inclined. In this case, the oil level in the crankcase is prevented from fluctuating. Therefore, it is possible to suppress excessively large amount of oil in the crankcase from being sucked through the first passage, and it is possible to suitably suppress shortage of oil in the crankcase.

  (9) The invention according to claim 9 is the blow-by gas recirculation device for the internal combustion engine according to any one of claims 1 to 8, wherein the internal combustion engine is mounted on a vehicle, and the first passage includes the first passage. The gist of the invention is that a variable mechanism for changing the position of the opening on one end side is provided, and the position of the opening is changed by the variable mechanism in accordance with the degree of inclination of the oil surface in the crankcase.

  In the in-vehicle internal combustion engine, a force proportional to the acceleration is generated in the oil in the crankcase during acceleration / deceleration or turning of the vehicle, so that the oil surface in the crankcase is inclined with respect to the horizontal plane. For this reason, depending on the position of the opening part of a 1st channel | path, there exists a possibility that the oil in a crankcase may be attracted | sucked too much through a 1st channel | path. As a result, the oil in the crankcase is insufficient, and there is a risk that the oil supplied to lubricate each part of the engine will be insufficient.

  In this regard, according to the above configuration, the position of the opening is changed by the variable mechanism in accordance with the degree of inclination of the oil surface in the crankcase with respect to the horizontal plane. For this reason, it can suppress that the oil in a crankcase is attracted | sucked too much through a 1st channel | path, and it can suppress suitably that the oil in a crankcase runs short.

  (10) The gist of the invention described in claim 10 is that, in the blow-by gas recirculation device for the internal combustion engine according to claim 9, the position of the opening is changed in accordance with the acceleration of the vehicle.

  The greater the acceleration of the vehicle, the greater the oil surface in the crankcase is inclined relative to the horizontal plane. According to the above configuration, since the position of the opening portion of the first passage is changed according to the acceleration of the vehicle, the inclination state of the oil surface in the crankcase can be accurately grasped based on the acceleration of the vehicle. The position of the part can be set appropriately.

  (11) A blowby gas recirculation device for an internal combustion engine according to claim 9 or claim 10, wherein the variable mechanism changes the position of the opening in the vertical direction as in the invention according to claim 11. Can be materialized.

1 is a cross-sectional view showing a cross-sectional structure of an internal combustion engine in a blow-by gas recirculation device for an internal combustion engine according to a first embodiment of the present invention, and particularly a cross-sectional view showing a cross-sectional structure inside a crankcase when the engine is stopped. FIG. 2 is a cross-sectional view showing a cross-sectional structure of the internal combustion engine of the embodiment, and particularly a cross-sectional view showing a cross-sectional structure in a crankcase during engine operation. FIG. 3 is a cross-sectional view showing an oil surface in the crankcase of the same embodiment, and particularly a cross-sectional view showing the relationship between the opening of the first conduit and the oil surface when the internal combustion engine is inclined. FIG. 7A is a cross-sectional view showing a cross-sectional structure in a crankcase when an acceleration / deceleration or turning of a vehicle is less than a predetermined degree, for a blow-by gas recirculation device for an internal combustion engine according to a second embodiment of the present invention; FIG. 4 is a cross-sectional view showing a cross-sectional structure in the crankcase when the acceleration / deceleration or turning of the vehicle is greater than a predetermined degree. The flowchart which shows the execution procedure of the opening part height adjustment routine in the embodiment.

<First Embodiment>
A first embodiment in which a blow-by gas recirculation device for an internal combustion engine according to the present invention is embodied will be described below with reference to FIGS. Note that the internal combustion engine of the present embodiment is an in-cylinder injection type gasoline engine mounted on a vehicle. In the following, the upper side in the vertical direction is simply referred to as the upper side, and the lower side in the vertical direction is simply referred to as the lower side.

As shown in FIG. 1, a plurality of cylinders 3 are formed in a cylinder block 2 of the internal combustion engine, and a piston 4 is provided in each cylinder 3 so as to be able to reciprocate.
A cylinder head 1 is provided above the cylinder block 2, and an intake port for supplying air to each cylinder 3 and an exhaust port for discharging exhaust from each cylinder 3 are formed in the cylinder head 1. Yes. Further, the cylinder head is provided with a valve operating system including an intake valve and an exhaust valve for opening and closing the intake port and the exhaust port. A cylinder head cover 1 a that covers the valve system is provided on the upper side of the cylinder head 1.

  A crankcase 7 is provided below the cylinder block 2 so as to cover the crankshaft 6. An oil pan 8 is provided below the crankcase 7, and oil is stored in the oil pan 8. The crankshaft 6 is connected to the piston 4 via a connecting rod 5.

  An intake passage 20 is connected to the intake port of the cylinder head 1. In the intake passage 20, an air cleaner 21, a throttle valve 22, a surge tank 23, and an intake manifold 24 are provided in this order from the upstream side.

Although not shown here, an exhaust passage is connected to the exhaust port of the cylinder head 1.
An oil strainer 9 that functions as an inlet portion of a supply passage that supplies oil to each part of the engine is provided in the oil pan 8. A suction port 9 a for sucking oil is opened on the lower surface of the oil strainer 9.

  Further, the internal combustion engine is provided with a blow-by gas recirculation device including a recirculation passage 30 that recirculates the blow-by gas in the crankcase 7 to the intake passage 20. Specifically, the reflux passage 30 includes a first conduit 31, an oil tank 32, a second conduit 34, an oil separator 35, and a third conduit 36.

  The oil tank 32 has a substantially cylindrical shape and is mounted outside the crankcase 7. Inside the oil tank 32, a filter member 33 made of a lipophilic material having a lower density than oil is accommodated. Specifically, the filter member 33 is made of, for example, polypropylene.

  The first conduit 31 extends in a substantially horizontal direction from an opening 31 a located in the crankcase 7, and bends and extends upward outside the crankcase 7. The first conduit 31 has a connection portion 31 b connected to the bottom surface 32 a of the oil tank 32. Here, the opening 31 a of the first conduit 31 is located at the approximate center in the horizontal direction in the crankcase 7.

  One end of a second conduit 34 is connected to the top surface 32 b of the oil tank 32. An inlet of an oil separator 35 is connected to the other end of the second conduit 34. In the present embodiment, a labyrinth separator is provided as the oil separator 35. A third conduit 36 is connected to the outlet of the oil separator 35. The other end of the third conduit 36 is connected to the surge tank 23. A known PCV valve 37 for metering blow-by gas that is returned to the surge tank 23 through the return passage 30 is provided in the middle of the third conduit 36.

  The cylinder head 1 and the cylinder block 2 are formed with a connection passage 40 that connects the inside of the crankcase 7 and the inside of the cylinder head cover 1a. A fourth conduit 38 is provided for connecting the upstream side of the throttle valve 22 and the cylinder head cover 1a in the intake passage 20 to introduce fresh air from the intake passage 20 into the crankcase 7 through the cylinder head cover 1a. ing. A check valve 39 is provided in the middle of the fourth conduit 38 to prevent the backflow of blow-by gas from the cylinder head cover 1a side, that is, the crankcase 7 side to the intake passage 20 side.

Here, the opening 31a of the first conduit 31 is provided so as to be positioned below a stop-time oil surface Lstop, which is an oil surface in the crankcase 7 when the engine is stopped.
The oil tank 32 is provided such that its bottom surface 32a is in the same position as the oil surface Lstop when stopped in the vertical direction.

  The recirculation passage 30 is configured such that the oil in the crankcase 7 is sucked into the oil tank 32 through the first conduit 31 by the negative pressure generated in the surge tank 23 during engine operation, and the oil surface in the crankcase 7 The opening 31a on the one end side of the first conduit 31 is configured to be exposed on the oil surface as it decreases.

Next, the operation of this embodiment will be described.
As shown in FIG. 1, the opening 31 a of the first conduit 31 is immersed in the oil in the crankcase 7 when the engine is stopped.

  When engine operation is started from this state, a negative pressure is generated in the surge tank 23 and the negative pressure is introduced into the recirculation passage 30. As a result, the pressure in the crankcase 7 becomes higher than the pressure in the recirculation passage 30, so that the oil in the crankcase 7 is sucked into the oil tank 32 through the first conduit 31. Along with this, the oil level in the crankcase 7 is lowered.

  Here, since the check valve 39 is provided in the middle of the fourth conduit 38, the blow-by gas in the crankcase 7 is prevented from flowing back to the intake passage 20 through the fourth conduit 38. For this reason, the pressure in the crankcase 7 is maintained high, and the oil in the crankcase 7 is quickly sucked into the oil tank 32 through the first conduit 31.

Then, as shown in FIG. 2, the opening 31 a of the first conduit 31 is exposed on the oil surface in the crankcase 7.
Incidentally, when the first conduit 31 having an inner diameter of 10 mm and a passage length of 300 mm to 500 mm is used, when the oil temperature is 20 ° C. to 100 ° C., the oil until the opening 31a of the first conduit 31 is exposed in the idle operation. Specifically, it takes about 10 seconds to suck 2 L of oil.

  As described above, when the opening 31 a of the first conduit 31 is exposed on the oil surface, the blow-by gas in the crankcase 7 is returned to the intake passage 20 through the return passage 30. Here, bubbling occurs when the blow-by gas passes through the liquid oil stored in the oil tank 32. As a result, oil mist contained in the blow-by gas, particularly components having a particle size of 10 μm or less, are adsorbed by the liquid oil.

  By the way, depending on the position of the opening of the first conduit, for example, when the opening of the first conduit is provided near the inner wall of the crankcase, excessive oil in the crankcase is sucked through the first conduit when the internal combustion engine is inclined. There is a risk that. As a result, there is a shortage of oil in the crankcase, and the oil cannot be suitably sucked through the suction port 9a of the oil strainer 9, and there is a risk that the oil supplied to the lubrication of each part of the engine will be insufficient.

  In this regard, according to the present embodiment, as shown in FIG. 3, the opening 31 a of the first conduit 31 is located at the approximate center in the horizontal direction in the crankcase 7, so that even if the internal combustion engine is inclined, Fluctuation of the oil level in the crankcase 7 at the position of the opening 31a of the first conduit 31 is suppressed. For this reason, an excessive amount of oil in the crankcase 7 is suppressed from being sucked through the first conduit 31, and a shortage of oil in the crankcase 7 is preferably suppressed.

  Further, when the engine operation is stopped and the negative pressure in the intake passage 20 disappears, the oil sucked into the oil tank 32 is returned to the crankcase 7 through the first conduit 31 by its own weight, and the oil tank The inside of 32 becomes empty. For this reason, the oil in the oil tank 32 is replaced every time the engine is stopped. As a result, it is possible to suppress the oil from adhering to the inner wall of the oil tank 32 and deteriorating, and the occurrence of sludge in the oil tank 32 is preferably suppressed.

By the way, when bubbling bubbles bounce in the oil tank 32, there is a possibility that oil mist having a large particle size is newly generated.
In this regard, according to the present embodiment, the filter member 33 floats on the oil surface in the oil tank 32 (see FIG. 2). For this reason, when the bubble of bubbling bounces, it is suppressed suitably that oil mist with a large particle size arises.

  As described above, components having a small particle size among the oil mist contained in the blow-by gas are accurately adsorbed by the liquid oil stored in the oil tank 32 when passing through the oil tank 32. To be reduced. However, the liquid oil in the oil tank 32 and the blow-by gas that has passed through the filter member 33 may contain oil mist having a large particle size to some extent.

  In this regard, according to the present embodiment, when the blow-by gas that has passed through the oil tank 32 passes through the oil separator 35, a component having a large particle diameter is captured from the oil mist contained in the blow-by gas.

  By the way, when the crankshaft 6 rotates, the oil stored in the crankcase 7 is agitated. Therefore, the higher the oil level, the more oil the crankshaft 6 agitates, and the greater the engine resistance that occurs when the crankshaft 6 agitates the oil. In particular, when the internal combustion engine is rotating at a high speed, the oil is frequently stirred by the crankshaft 6 so that bubbles are mixed in the oil and the oil surface becomes higher, so that the engine resistance is further increased.

  In this regard, according to the present embodiment, as described above, the oil level in the crankcase 7 is kept low during engine operation, so that less oil is stirred by the crankshaft 6. Therefore, the engine resistance generated when the crankshaft 6 agitates the oil is suitably reduced.

  In the present embodiment, the first conduit 31 corresponds to the first passage of the present invention, and the oil tank 32 corresponds to the tank according to the present invention. The second conduit 34 and the third conduit 36 correspond to the second passage according to the present invention. The fourth conduit 38 and the connection passage 40 correspond to the introduction passage according to the present invention.

According to the blow-by gas recirculation device for an internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(1) The blow-by gas recirculation device for the internal combustion engine includes a recirculation passage 30 that recirculates the blow-by gas in the crankcase 7 to the surge tank 23 of the intake passage 20 of the internal combustion engine. Further, the first conduit 31 having one end opened in the crankcase 7, the oil tank 32 connected to the other end of the first conduit 31, the second conduit 34 connecting the oil tank 32 and the intake passage 20, and the second conduit 34. Three conduits 36 are provided as the reflux passage 30. The opening 31a on the one end side of the first conduit 31 is provided so as to be positioned vertically below the stop-time oil surface Lstop, which is the oil surface in the crankcase 7 when the engine is stopped. In the recirculation passage 30, the oil in the crankcase 7 is sucked into the oil tank 32 through the first conduit 31 by the negative pressure generated in the surge tank 23 as the engine is operated, and the oil level in the crankcase 7 is lowered. Accordingly, the opening 31a on one end side of the first conduit 31 is configured to be exposed on the oil surface. According to such a configuration, oil mist contained in the blow-by gas can be accurately reduced, and accumulation of sludge in the reflux passage 30 can be suitably suppressed.

  Furthermore, since the oil level in the crankcase 7 can be kept low during engine operation, less oil is stirred by the crankshaft 6. Therefore, the engine resistance generated when the crankshaft 6 agitates the oil can be suitably reduced.

  (2) The oil tank 32 is provided outside the crankcase 7. When the oil tank is provided inside the crankcase, it is necessary to increase the size of the crankcase, and the design of the existing crankcase must be greatly changed. In this regard, according to the configuration of the present embodiment, since the oil tank 32 is provided outside the crankcase 7, it is not necessary to increase the size of the crankcase 7. Therefore, the present invention can be embodied without greatly changing the design of the existing crankcase 7.

  (3) The first conduit 31 has a connection portion 31 b connected to the bottom surface 32 a of the oil tank 32. The connecting portion 31b is provided at the same position as the oil surface Lstop when stopped in the vertical direction. According to such a configuration, it is possible to accurately suppress the oil from adhering to the inner wall of the oil tank 32 and to deteriorate, and it is possible to suitably suppress the generation of sludge in the oil tank 32.

In addition, oil can be suitably prevented from leaking when the oil tank 32 is replaced, and workability can be improved.
(4) A labyrinth type oil separator 35 is provided between the second conduit 34 and the third conduit 36. According to such a configuration, when the blow-by gas that has passed through the oil tank 32 passes through the oil separator 35, a component having a large particle diameter is captured from the oil mist contained in the blow-by gas. Therefore, the oil mist contained in the blow-by gas returned to the surge tank 23 can be accurately reduced regardless of the particle diameter.

  (5) A filter member 33 made of a material having a density lower than that of oil is accommodated in the oil tank 32. According to such a configuration, since the filter member 33 comes to float on the oil surface in the oil tank 32, it is possible to suitably suppress the generation of oil mist having a large particle diameter when bubbles of bubbling bounce. become able to.

  (6) A check valve 39 for preventing the backflow of blow-by gas from the crankcase 7 side to the intake passage 20 side is provided in the middle of the fourth conduit 38 for introducing fresh air into the crankcase 7 from the intake passage 20. It has been. According to such a configuration, since the check valve 39 is provided in the middle of the fourth conduit 38, the reverse flow of blow-by gas from the crankcase 7 side to the intake passage 20 side through the fourth conduit 38 is prevented. Become. Accordingly, the oil in the crankcase 7 is quickly sucked into the oil tank 32 through the first conduit 31.

  Moreover, it is possible to suppress oil from adhering to the inner wall of the intake passage 20 due to the backflow of blow-by gas, and it is possible to suppress the generation of sludge on the inner wall.

  (7) The opening 31a of the first conduit 31 is located in the center of the crankcase 7 in the horizontal direction. According to such a structure, it can suppress that the oil in the crankcase 7 is attracted | sucked too much through the 1st conduit | pipe 31, and it can suppress suitably that the oil in the crankcase 7 runs short. It becomes like this.

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. In the present embodiment, a variable mechanism that varies the position of the opening on one end side of the first passage is provided, and the position of the opening by the variable mechanism according to the degree of inclination of the oil surface in the crankcase. Is different from the first embodiment. Moreover, about the structure same as 1st Embodiment, the overlapping description is omitted by attaching | subjecting the same code | symbol.

Hereinafter, the difference from the first embodiment will be mainly described.
As shown in FIGS. 4A and 4B, a suction pipe 151 that extends downward is connected to the tip of the first conduit 131 via a variable mechanism 150. The variable mechanism 150 includes an electric motor and a conversion mechanism that converts the rotational motion of the motor into linear motion of the suction pipe 151, and the position of the opening 152 of the suction pipe 151 in the vertical direction (hereinafter referred to as “opening”). The height of the portion 152 is variable. The variable mechanism 150 is driven and controlled by the electronic control device 160.

The electronic control device 160 is electrically connected to an acceleration sensor 161 that detects the acceleration A of the vehicle.
By the way, a force proportional to the acceleration acts on the oil in the crankcase 7 at the time of acceleration / deceleration or turning of the vehicle. Therefore, as shown by a two-dot chain line in FIG. The oil level inside is inclined. For this reason, if the height of the opening 152 of the suction pipe 151 is lowered, an excessive amount of oil in the crankcase 7 may be sucked through the suction pipe 151 and the first conduit 131. As a result, there is a shortage of oil in the crankcase 7, and the oil cannot be suitably sucked through the suction port 9 a of the oil strainer 9, and there is a possibility that the oil supplied to the lubrication of each part of the engine is insufficient.

  Therefore, in the present embodiment, in order to suppress the occurrence of such inconvenience, the degree of inclination of the oil surface in the crankcase 7 is grasped through the electronic control unit 160, and the variable mechanism 150 is used according to the degree of inclination of the oil surface. The height of the opening 152 is changed. Specifically, as the vehicle acceleration A increases, the oil surface in the crankcase 7 tilts more greatly with respect to the horizontal plane. Therefore, the height of the opening 152 depends on the vehicle acceleration A detected by the acceleration sensor 161. To change.

  Next, with reference to FIG. 5, an execution procedure of a routine for adjusting the height of the opening 152 (hereinafter, height adjustment routine) will be described. This routine is repeatedly executed at predetermined intervals by the electronic control unit 160 during engine operation.

  In this series of processing, first, the acceleration A of the vehicle at that time is read (step S1). Next, based on the acceleration A of the vehicle, it is determined whether the vehicle is accelerating / decelerating or turning more than a predetermined degree (step S2). Specifically, for example, when the state where the acceleration A of the vehicle is a predetermined value or more continues for a predetermined time or more, it is determined that the vehicle is accelerating / decelerating or turning more than a predetermined degree. The predetermined value and the predetermined time are set in advance through experiments or the like. Here, when it is determined that the vehicle is not accelerating / decelerating or turning more than a predetermined degree (step S2: “NO”), the height H of the opening 152 is then set to the first height H1. Set (step S3).

  On the other hand, when it is determined that the vehicle is accelerating / decelerating or turning more than a predetermined degree (step S2: “YES”), the oil in the crankcase 7 is then passed through the suction pipe 151 and the first conduit 131. In order to prevent the oil tank 32 from being excessively sucked, the height H of the opening 152 is set to a second height H2 that is higher than the first height H1 (step S4).

When the height H of the opening 152 is set in this way, the variable mechanism 150 is then driven so that the set height H is reached, and this series of processing is once completed.
Next, the operation of this embodiment will be described.

  The inclination state of the oil surface in the crankcase 7 is grasped based on the acceleration A of the vehicle. Then, the height of the opening 152 is changed by the variable mechanism 150 according to the grasped degree of inclination of the oil surface. Specifically, when the vehicle is accelerating or decelerating or turning more than a predetermined degree, as shown in FIG. 4B, the opening 152 of the suction pipe 151 rises to the second height H2. . For this reason, the oil in the crankcase 7 is restrained from being excessively sucked through the suction pipe 151 and the first conduit 131. As a result, the occurrence of inconvenience that the oil in the crankcase 7 is insufficient and the oil cannot be suitably sucked through the suction port 9a of the oil strainer 9 is suitably suppressed.

According to the blow-by gas recirculation device for an internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(8) The blow-by gas recirculation device for the internal combustion engine includes a variable mechanism 150 that varies the height of the opening 152 of the suction pipe 151. In addition, the electronic control unit 160 changes the height of the opening 152 by the variable mechanism 150 according to the degree of inclination of the oil surface in the crankcase 7. According to such a structure, it can suppress that the oil in the crankcase 7 is attracted | sucked too much, and it becomes possible to suppress suitably that the oil in the crankcase 7 runs short.

  (9) The position of the opening 152 in the vertical direction is changed according to the acceleration A of the vehicle. According to such a configuration, the state of inclination of the oil surface in the crankcase 7 can be accurately grasped based on the acceleration A of the vehicle, and the position of the opening 152 can be set appropriately.

  The blow-by gas recirculation device for an internal combustion engine according to the present invention is not limited to the configuration exemplified in the above-described embodiment, and can be implemented as, for example, the following forms appropriately modified.

  In the second embodiment, the suction pipe 151 extending in the vertical direction and the variable mechanism 150 that changes the height of the opening 152 of the suction pipe 151 are illustrated. In addition to this function, a variable mechanism that can change the position of the opening of the suction pipe in the horizontal direction may be adopted. Alternatively, instead of the second embodiment, the suction pipe may extend in the horizontal direction, and the position of the opening of the suction pipe in the horizontal direction may be varied.

  In each of the above embodiments, the check valve 39 is provided in the middle of the fourth conduit 38. However, such a check valve may be provided in the middle of the connection passage 40. Even in this case, the effect according to the effect (6) of the first embodiment can be obtained.

  As in the above embodiments and modifications thereof, the check valve 39 is provided in the middle of the introduction passage (the fourth conduit 38, the connection passage 40), so that the oil in the crankcase 7 is oil through the first conduit 31. It is desirable for prompt suction into the tank 32. Further, it is desirable to suppress the oil from adhering to the inner wall of the intake passage 20 due to the backflow of blow-by gas and to suppress the generation of sludge on the inner wall. However, the present invention is not limited to such a check valve, and the check valve can be omitted if the above-described problem can be ignored.

  In each of the above embodiments, the filter member 33 is illustrated as being formed of polypropylene. However, instead of this, the filter member may be formed of another lipophilic material such as polyester. Even in this case, the effect according to the effect (5) of the first embodiment can be obtained.

  In each of the above embodiments, the labyrinth type oil separator 35 is exemplified, but instead of this, a cyclone type oil separator or a filter type oil separator may be adopted. Also, a plurality of these separators can be combined in series or in parallel.

  As in each of the above embodiments, providing the oil separator 35 between the second conduit 34 and the third conduit 36 is a component having a large particle size in the oil mist contained in the blow-by gas that has passed through the oil tank 32. This is desirable in order to suitably capture the. However, when the oil mist contained in the blow-by gas that has passed through the oil tank 32 can be ignored, such an oil separator may be omitted.

  In each of the above embodiments, the connection portion 31b of the first conduit 31, that is, the bottom surface 32a of the oil tank 32 is exemplified in the vertical direction at the same position as the oil surface Lstop at the time of stop. Instead of this, the connecting portion of the first conduit may be provided above the oil level Lstop at the time of stop. Even in this case, the effect according to the effect (3) of the first embodiment can be obtained.

  In each of the above embodiments, the configuration in which the first conduit 31 is connected to the bottom surface 32a of the oil tank 32 is illustrated, but instead, the configuration in which the first passage is connected to the lower end of the side surface of the tank. Can also be adopted.

  As in the above embodiments, the connection portion of the first passage is provided at the same position as or higher than the oil surface Lstop at the time of stop in the vertical direction, so that the tank is emptied when the engine is stopped. It is desirable for accurately suppressing the deterioration of the oil attached to the inner wall of the tank. However, the present invention is not limited to this, and the connecting portion of the first passage can be provided below the oil level Lstop at the time of stop. Even in this case, since a part of the oil sucked into the tank can be replaced when the engine is stopped, it is possible to suppress the deterioration of the oil in the tank.

  -It is desirable to provide the oil tank 32 outside the crankcase 7 as in the above embodiment in order to embody the present invention without greatly changing the design of the crankcase 7 or the oil pan 8. However, the present invention is not limited to this, and the tank may be provided inside the crankcase and the oil pan.

  -The tank according to the present invention is not limited to the shape illustrated in the above-described embodiment, in other words, in the middle of the recirculation passage for returning the blowby gas in the crankcase to the intake passage of the internal combustion engine, that is, the first passage and the first passage. What is necessary is just a site | part which is located between 2 channel | paths and the passage cross-sectional area in a recirculation | reflux path is partially expanded compared with another site | part.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder head, 1a ... Cylinder head cover, 2 ... Cylinder block, 3 ... Cylinder, 4 ... Piston, 5 ... Connecting rod, 6 ... Crankshaft, 7 ... Crankcase, 8 ... Oil pan, 9 ... Oil strainer, 9a ... Suction port, 20 ... intake passage, 21 ... air cleaner, 22 ... throttle valve, 23 ... surge tank, 24 ... intake manifold, 30 ... return passage, 31 ... first conduit (first passage), 31a ... opening, 31b ... Connection part 32 ... Oil tank 32a ... Bottom surface 32b ... Top surface 33 ... Filter member 34 ... Second conduit (second passage) 35 ... Labyrinth type oil separator (second passage) 36 ... Third Conduit (second passage) 37 ... PCV valve 38 ... Fourth conduit (introduction passage) 39 ... Check valve 40 ... Connection passage (introduction passage) 131 ... No. Conduit (first passage), 150 ... variable mechanism (first passage), 151 ... intake pipe (first path), 152 ... opening, 160 ... electronic control unit, 161 ... acceleration sensor.

Claims (11)

In a blow-by gas recirculation device for an internal combustion engine comprising a recirculation passage for recirculating blow-by gas in a crankcase to an intake passage of the internal combustion engine,
A first passage having one end opened in the crankcase, a tank to which the other end of the first passage is connected, and a second passage for connecting the tank and the intake passage as the return passage,
The opening on the one end side of the first passage is provided so as to be positioned vertically below the oil surface at the time of stop, which is an oil surface in the crankcase when the engine is stopped,
In the recirculation passage, the oil in the crankcase is sucked into the tank through the first passage by the negative pressure generated in the intake passage as the engine is operated, and the oil level in the crankcase is lowered. Accordingly, the opening on the one end side of the first passage is configured to be exposed on the oil surface. The blow-by gas recirculation device for an internal combustion engine according to claim 1,
The blow-by gas recirculation device for an internal combustion engine, wherein the tank is provided outside the crankcase. The blow-by gas recirculation device for an internal combustion engine according to claim 1 or 2,
The first passage has a connection portion connected to a lower end portion in the vertical direction of the tank, and the connection portion is at the same position as the oil surface at the time of stop or above the oil surface at the time of stop in the vertical direction. A blow-by gas recirculation device for an internal combustion engine, which is provided. The blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 3,
An oil separator is provided in the middle of the second passage. A blow-by gas recirculation device for an internal combustion engine. The blow-by gas recirculation device for an internal combustion engine according to claim 4,
The blow-by gas recirculation device for an internal combustion engine, wherein the oil separator is at least one of a labyrinth separator, a cyclone separator, and a filter separator. In the blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 5,
A blow-by gas recirculation device for an internal combustion engine, wherein a filter member made of a material having a density lower than that of oil is accommodated in the tank. The blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 6,
A check valve for preventing a reverse flow of blow-by gas from the crankcase side to the intake passage side is provided in the middle of the introduction passage for introducing fresh air from the intake passage into the crankcase. A blow-by gas recirculation device for an internal combustion engine. The blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 7,
One end of the first passage is opened close to a central position in the horizontal direction in the crankcase. A blow-by gas recirculation device for an internal combustion engine. The blow-by gas recirculation device for an internal combustion engine according to any one of claims 1 to 8,
The internal combustion engine is mounted on the vehicle,
A variable mechanism for changing the position of the opening on the one end side of the first passage;
The blow-by gas recirculation device for an internal combustion engine, wherein the position of the opening is changed by the variable mechanism in accordance with the degree of inclination of the oil surface in the crankcase. The blow-by gas recirculation device for an internal combustion engine according to claim 9,
A blow-by gas recirculation device for an internal combustion engine, wherein the position of the opening is changed according to the acceleration of the vehicle. The blow-by gas recirculation device for an internal combustion engine according to claim 9 or 10,
The variable mechanism changes the position of the opening in the vertical direction. A blow-by gas recirculation device for an internal combustion engine.