JPH0741855Y2 - PCV device for internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a PCV (Positive Crank Case Ventilation) device for an internal combustion engine, and particularly for forcibly returning the oil separated in the expansion chamber to the crank case. Related to PCV equipment.

[Prior Art] In an internal combustion engine mounted on a vehicle, blow-by gas containing combustible hydrocarbons leaking to the crankcase is returned to the intake side to be recombusted, and at the same time, the inside of the crankcase is forcibly forced. A PCV device for ventilation is provided.

Various types of PCV devices have been proposed in the past, and as one example thereof, Japanese Patent Publication No. 64-11804 is known. The PCV device disclosed in this publication is designed to separate the oil component in the blow-by gas on the upstream side and the downstream side of the PCV valve, and to evaporate the fuel component and send it to the intake system without waste. Has become. Therefore,
The amount of oil mixed into the intake system is suppressed, and the deterioration of oil is suppressed by separating the fuel component and water.

[Problems to be Solved by the Invention] However, the above-mentioned Japanese Patent Publication No. 64-11804 still has a problem to be solved. That is, in this device,
The oil separated in the expansion chamber will be discharged from the oil return hole of the PCV valve, but it will be difficult for the oil to return due to the reverse blow-by gas flow when the engine is operating, and if the engine is operated for a long time, , A lot of oil accumulates in the expansion chamber. Therefore, a large amount of oil in the expansion chamber is mixed into the intake system, which causes the following problems.

(A) In the electronically controlled fuel injection device, the oil in the blow-by gas adheres to the tip of the injector to generate a deposit. Therefore, the area of the fuel injection passage of the injector is reduced, and the amount of combustion injection from the injector is extremely reduced.

(B) Deposit of oil in the intake system causes a deposit to be formed on the head portion of the intake valve, and the adhesion of fuel to the deposit transiently makes it difficult to control the air-fuel ratio.

(C) The generation of deposits on the wall surface of the combustion chamber causes deterioration of combustion.

(D) Along with the increase in the amount of oil taken away, the oil consumption will increase significantly.

By the way, if the oil accumulated in the expansion chamber is surely returned to the crankcase side during operation of the engine, the amount of oil mixed into the intake system can be remarkably suppressed. There was no device forcibly returning it into the crankcase while the engine was running.

The present invention focuses on the above problem, and forcibly returns the oil separated in the expansion chamber to the inside of the crankcase during operation of the engine, and can significantly suppress the inflow of oil into the intake system. The purpose is to provide.

[Means for Solving the Problems] A PCV device for an internal combustion engine according to the present invention, which meets this object, is
The expansion chamber for oil separation, which is located downstream of the valve, is provided with an oil discharge means for returning the oil accumulated in the expansion chamber to the inside of the crankcase, which is operated by the fluctuation of the pressure in the intake pipe.

[Operation] In the PCV device of the internal combustion engine configured as described above,
The oil discharge means is operated by the fluctuation of the pressure in the intake pipe. That is, when the engine is operating, the pressure in the intake pipe fluctuates depending on the load state is used to operate the oil discharging means, so that the oil staying in the expansion chamber is forced by the oil discharging means when the engine is operating. It is ejected and reliably returned to the crankcase. Therefore,
A large amount of oil in the expansion chamber is prevented from flowing into the intake system, and the harmful effects of the inflow of oil are eliminated.

[Embodiment] A preferred embodiment of a PCV device for an internal combustion engine according to the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 4 show a first embodiment of the present invention. In the figure, 1 indicates a cylinder head of an internal combustion engine, and 2 indicates a cylinder head cover. An oil separator 3 for separating oil contained in blow-by gas is attached inside the cylinder head cover 2. The cylinder head cover 2 has an expansion chamber cover 5 for forming an expansion chamber 4 for oil separation.
Is installed. Outer wall 2a of cylinder head cover 2
A PCV valve 6 that connects the inside of the cylinder head cover 2 and the expansion chamber 4 is attached to this. PCV valve 6
Has a function of controlling the flow rate of blow-by gas as is well known. The expansion chamber cover 5 is provided with an outflow port 7, and the outflow port 7 is connected via a rubber hose 8 to an intake manifold 21 as an intake pipe.

At the lowermost part of the expansion chamber 4, an oil discharge means 10 for returning the oil accumulated in the expansion chamber 4 to the crankcase 9 is provided. The oil draining means 10 includes a case 11, a piston 12,
It is composed of a compression coil spring 13 and a stop ring 14.

The case 11 is fixed so as to penetrate the outer wall 2a of the cylinder head cover 2 like the PCV valve 6. Case
11 is formed in a cylindrical shape, and the end surface on the expansion chamber 4 side is closed. A piston 12 is slidably fitted in the case 11. The piston 12 is, as shown in FIG.
The sectional shape in the axial direction is substantially H-shaped. A compression coil spring 13 for urging the piston 12 in the direction opposite to the expansion chamber 4 side is housed in the case 11. A stop ring (E ring) 14 that prevents the piston 12 from coming out of the case 11 by the urging force of the compression coil spring 13 is attached to the inner wall surface of the case 11.

The case 11 is provided with an oil inlet 15, an oil outlet 16, and vent holes 17, 18, and 21. The oil inflow port 15 is open to the expansion chamber 4 side, and the oil outflow port 16 is open to the crankcase 9 side. At the center of the piston 12,
It has a storage chamber 19 for storing the oil 20. A ventilation hole 22 is provided in a wall portion of the piston 12 located in the storage chamber 13. For example, when the negative pressure in the expansion chamber 4 is large, the piston 12 has a compression coil spring as shown in FIG.
It overcomes the urging force of 13 and moves to the expansion chamber 4 side. In this case, the oil 20 accumulated in the lower part of the expansion chamber 4
Flows into the reservoir chamber 19 of the piston 12 via the oil inlet 15. On the contrary, the piston 12 moves to the stop ring 14 side by the urging force of the compression coil spring 13 when the negative pressure in the expansion chamber 4 becomes small or when the negative pressure is positive, as shown in FIG. It is supposed to do. In this case, the oil that has flowed into the reservoir chamber 19 of the piston 12 moves together with the piston 12 and is discharged from the oil outlet 16 into the crankcase 9.

In this way, the piston 12 has a function of reciprocating due to the fluctuation of the pressure in the intake pipe and discharging the oil in the reservoir chamber 19. The intake hole 21 is for surely discharging oil, and the vent hole 22 of the piston 12 is for surely inflowing and outflowing oil into and from the reservoir chamber 19.

Next, the operation of the first embodiment will be described.

When the engine is started, the pressure in the expansion chamber 4 communicating with the intake manifold 21 via the rubber hose 8 changes, and this pressure fluctuation activates the oil discharge means 10. When the load of the engine is low, the amount of intake air supplied into the combustion chamber (not shown) is small, so the pressure in the expansion chamber 4 communicating with the intake manifold 21 also becomes negative, and the air in the case 11 passes through the vent hole 17. Is discharged. Therefore, the piston
12 is moved to the expansion chamber 4 side while compressing the compression coil spring 13. When the piston 12 moves toward the expansion chamber 4, the oil 20 stored in the lower portion of the expansion chamber 4 flows into the storage chamber 19 of the piston 12 via the oil inlet 15. In this case, since the storage chamber 19 communicates with the expansion chamber 4 via the other vent hole 18, the oil 20 is smoothly flowed into the storage chamber 19.

When the engine changes from a low load state to a high load state, the amount of intake air supplied to the combustion chamber increases and the intake manifold 21
The pressure of the expansion chamber 4 that communicates with the pressure increases and becomes a positive pressure. Therefore, the piston 12 is pushed back to the crankcase 9 side by the urging force of the compression coil spring 13, and the piston 12
Stops at a position where the storage chamber 19 overlaps the oil outlet 16.
Therefore, the oil in the storage chamber 19 is discharged into the crankcase 9 as shown in FIG. Below, expansion chamber 4
The above operation is repeated with the change in the internal pressure.

As described above, in this embodiment, the oil 20 accumulated in the expansion chamber 4 during the operation of the engine is forcibly returned to the crankcase 9 by the movement of the piston 12, so that the expansion chamber 4 can be operated for a long time. A large amount of oil does not accumulate in 4, and the amount of oil mixed into the intake system is greatly suppressed.

Second Embodiment FIG. 5 shows a second embodiment of the present invention. The second embodiment is different from the first embodiment only in the structure of the oil discharging means, and the other parts are the same as the first embodiment. Therefore, the same parts as those in the first embodiment are designated by the same reference numerals. The description of the parts conforming to is omitted, and only the different parts will be described.

In FIG. 5, reference numeral 31 in the drawing denotes an oil discharging means, and the oil discharging means 31 is provided in the lower portion of the expansion chamber 4. The oil discharge means 31 is composed of a cylinder 32, a piston 33, and a diaphragm actuator 34. The cylinder 32 is fixed so as to penetrate the outer wall 2a of the head cover 2. A piston 33 is slidably fitted in the cylinder 32, and the piston 33 is a diaphragm actuator fixed to the outer peripheral surface of the cylinder head cover 2.
It is connected to the rod 34a of 34. The diaphragm actuator 34 is connected to an intake manifold (not shown) via the rubber hose 8. Inside the diaphragm actuator 34, there is a spring member 3 for urging the rod 34a.
4b is arranged so that the rod 34a is expanded and contracted by changing the pressure of the intake manifold and the biasing force of the spring member 34b.

The cylinder 32 is provided with an oil inlet port 35, an oil outlet port 36, and vent holes 37 and 39. A storage chamber 38 for storing oil is formed in the piston 33. A ventilation hole 33a is provided in a wall portion of the piston 33 located in the storage chamber 38. The reservoir chamber 38 is configured to overlap the inflow port 35 due to the movement of the piston when the inside of the intake manifold has a negative pressure. Conversely, when the inside of the intake manifold has a small negative pressure or a positive pressure, As the piston moves, it overlaps the oil outlet 36 and the vent hole 37.

In the second embodiment configured as described above, since the piston 33 is operated via the diaphragm actuator 34, the piston 33 can be operated with a large force and the reliability of operation can be improved. it can. Further, the responsiveness of the operation of the piston 33 can be enhanced as compared with the first embodiment in which the piston is operated by the pressure change of the expansion chamber 4.

Third Embodiment FIG. 6 shows a third embodiment of the present invention, particularly an example applied to an engine using methanol as a fuel.

In FIG. 6, reference numeral 41 in the figure denotes an oil separator for supplementing the oil contained in the blow-by gas. The oil separator 41 is provided with a gas inlet 42 and a gas outlet 45. The gas inlet 42 has a line 43 and a PCV valve 40.
And communicates with the inner space of the cylinder head cover 44. The gas outlet 45 communicates with a downstream side of a position in the intake pipe 47 where the throttle valve 48 is arranged, via a pipe line 46. Further, the inner space of the cylinder head cover 44 communicates with the air cleaner 50 via a conduit 49.

An expansion chamber 51 is formed in the oil separator 41. Inside the expansion chamber 51, as shown in FIG. 7, a ring-shaped partition plate 52 having a function of capturing oil is arranged. The partition plate 52 is arranged between the gas inflow port 42 and the gas outflow port 45, and the outer peripheral portion is fixed to the inner wall surface of the expansion chamber 51. A hole 53 is formed in the center of the partition plate 52, into which a rod of a diaphragm actuator 62 described later is inserted. Around the hole 53, a plurality of small holes 54 are formed.

The partition plate 52 may have a configuration in which a plurality of slits 55 extending radially are provided around the hole 53, as shown in FIG.

The expansion chamber 51 is provided with oil discharge means 61. The oil discharge means 61 is composed of a diaphragm actuator 62, a piston 63, a cylinder 64, a spring 65, and a check valve 66. Diaphragm actuator 62
Has a diaphragm 62a, a rod 62b, and a spring 62c, and the diaphragm chamber 62d is partitioned by the diaphragm 62a. The spring 62c is housed in the diaphragm chamber 62d and biases the diaphragm 62a. The rod 62b is connected to the diaphragm 62a. The diaphragm chamber 62d communicates with the downstream side of the throttle valve 48 in the intake pipe 47 through a pipe line 67, and a negative pressure acts on the diaphragm chamber 62d.

The rod 62b of the diaphragm actuator 62 is connected to the expansion chamber 5
It extends to the vicinity of a cylinder 64 formed in the lower part of 1. A piston 63 is slidably fitted in the cylinder 64, and the top of the piston 63 is in contact with the rod 62b of the diaphragm actuator 62. In the cylinder 64,
A spring 65 for urging the piston 63 toward the rod 62b side is provided. A plurality of grooves 63a extending in the axial direction are formed on the outer peripheral surface of the piston 63. The groove 63a is formed only below the substantially central portion of the piston 63.
The upper part of the piston 63 with which the rod 62b abuts is the cylinder 64.
The diameter between the piston 63 and the cylinder 64 is substantially the same as the diameter of the cylinder, and the clearance between the upper portion of the piston 63 and the cylinder 64 is such that liquid leakage hardly occurs.

The inside of the cylinder 64 communicates with the check valve 66 via a passage 68. The check valve 66 is urged to block the passage 68 by the urging force of the check ball 66a and the spring 66b. The check valve 66 communicates with the inner space of the cylinder head cover 44 via a pipe line 69.

The piston 63 slides in the cylinder 64 via the diaphragm actuator 62 according to the change in the pressure in the intake pipe 47, and the oil accumulated in the lower portion of the expansion chamber 51 slides in the piston 63. Is discharged to the check valve 66 side. The check valve 66 has a function of blocking the flow of blowby gas from the inner space of the cylinder head cover 44 to the piston 63 side.

In the third embodiment configured in this way, the blow-by gas containing a large amount of oil mist flows into the expansion chamber 51 from the gas inlet 42 via the PCV valve 40 and the pipe 43. When the blow-by gas flows into the expansion chamber 51, the flow velocity thereof is rapidly reduced, and the partition plate 52 traps the oil mixed in the blow-by gas. This oil is
Remaining in the lower part of the
It is guided to the intake pipe 47 side via 46.

The oil stored in the lower portion of the expansion chamber 51 is returned to the crankcase (inner space of the cylinder head cover 44) side by the movement of the piston 63 accompanying the fluctuation of the pressure in the intake pipe 47. That is, when the engine load is low, the negative pressure in the intake pipe 47 increases, so the pressure in the diaphragm chamber 62d also decreases, and the rod 62b is pulled toward the diaphragm chamber 62d side. In this case, the expansion chamber 51 is inserted through the groove 63a of the piston 63.
And the inside of the cylinder 64 communicate with each other, and the oil accumulated in the expansion chamber 51 flows into the cylinder 64.

When the engine changes from a low load state to a high load state, the negative pressure in the intake pipe 47 becomes small, and the diaphragm 62a is pushed back by the spring 62c. In this case, the movement of the piston 63 causes the groove 63a of the piston 63 to completely enter the cylinder 64,
The upper part of the piston 63 completely separates the expansion chamber 51 and the cylinder 64.

When the piston 63 is pressed by the rod 62b of the diaphragm actuator 62, the pressure in the cylinder 64 becomes high, the check ball 66a of the check valve 66 that closes the passage 68 is pushed back, and the oil in the cylinder 64 remains in the check valve 66. Discharged to the side. The oil discharged to the check valve 66 side is
It is returned to the inner space of the cylinder head cover 44 via the pipe 69 and reaches an oil pan (not shown).

As described above, also in the present embodiment, the oil stored in the expansion chamber 51 is automatically returned to the crankcase side during the operation of the engine, so that the expansion chamber 51 can be operated for a long time.
A large amount of oil does not accumulate in the intake system, and the amount of oil mixed into the intake system can be significantly controlled.

In addition, this embodiment can be applied to a gasoline engine.
Therefore, the generation of deposits in the intake passage due to the inflow of oil is suppressed, and HC emissions are reduced. Further, by suppressing the inflow amount of oil, the particulate emission caused by the additive in the oil and the high boiling point hydrocarbon can be reduced, and the deterioration of the catalyst caused by the combustion of P (phosphorus) in the oil can be suppressed. It

FIG. 8 shows a fourth embodiment of the present invention. The present embodiment is different from the third embodiment only in the oil discharging means, and other parts are the same as those in the third embodiment.
Similar parts are designated by the same reference numerals as in the third embodiment, and only different parts will be described.

In the third embodiment, a plurality of grooves 63a are formed in the piston 63,
Although the expansion chamber 51 and the inside of the cylinder 64 are communicated with each other through the groove 63a, a plurality of grooves 64a are formed on the inner wall surface of the cylinder 64 in this embodiment. The groove 64a extends from the bottom surface of the expansion chamber 51 to almost the center of the cylinder 64.

In the fourth embodiment configured as described above, since the groove 64a is formed in the bottom surface of the expansion chamber 51, the oil accumulated in the lower portion of the expansion chamber 51 easily flows into the cylinder 64, and the oil crankcase The return to the side is facilitated.

[Advantages of the Invention] As described above, when the PCV device for an internal combustion engine according to the present invention is used, the expansion chamber for oil separation located downstream of the PCV valve is actuated by the fluctuation of the pressure in the intake pipe, and the expansion chamber is operated. Since an oil discharge means for returning the accumulated oil to the inside of the crankcase is provided, it is possible to forcibly discharge the oil accumulated in the expansion chamber when the engine is operating, and the expansion chamber can be operated even for a long time of operation. It is possible to prevent the accumulation of a large amount of oil.

Therefore, a large amount of oil in the expansion chamber can be suppressed from flowing into the intake system, and the amount of oil consumption can be suppressed.

Further, by suppressing the amount of oil mixed into the intake system, the generation of deposits on the intake valve and the wall surface of the combustion chamber is suppressed, and the operating performance of the engine can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a PCV device for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is an enlarged sectional view in the vicinity of the oil discharge means in FIG. 1, and FIGS. 2 is a sectional view showing the operating state of the oil draining means, FIG. 5 is a sectional view of a main part of a PCV device for an internal combustion engine according to a second embodiment of the present invention, and FIG. 6 is a third embodiment of the present invention. FIG. 7 is a schematic configuration diagram of such a PCV device for an internal combustion engine, FIG. 7 is a plan view of a partition plate in FIG. 6, FIG. FIG. 9 is a plan view showing a modified example of the partition plate of FIG. 2,44 ...... Cylinder head cover 4,51 ...... Expansion chamber 6,40 ...... PCV valve 9 ...... Crankcase 10,61 ...... Oil discharge means 21, 47 ...... Intake pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-210211 (JP, A) actual development S56-111212 (JP, U) actual development S58-122722 (JP, U) actual development 1- 105712 (JP, U) Actual opening 60-194116 (JP, U) Actual opening 61-17113 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. An expansion chamber for oil separation, which is located downstream of the PCV valve, is provided with oil discharge means for returning the oil accumulated in the expansion chamber to the inside of the crankcase by operating due to fluctuations in pressure in the intake pipe. PCV device for internal combustion engine.