JPH0627772Y2 - Blow-by gas reduction device - Google Patents

Description

[Detailed description of the device]

[Industrial applications]

The present invention relates to a blowby gas returning device for an engine, and more particularly to a structure of a blowby gas passage.

[Prior art]

As the engine burns, blow-by gas blows from the combustion chamber through the gap between the cylinder wall surface and the piston into the crankcase. The blow-by gas contains a large amount of unburned components (HC) and water, and if this blow-by gas mixes with the oil in the crankcase, there is a problem that it causes deterioration of the oil and rust in the crankcase. It was Therefore, conventionally, a blow-by gas returning device has been used in which blow-by gas blown into the crankcase is returned to the intake passage to be re-combusted and the crankcase is forcibly ventilated. FIG. 6 is a vertical sectional view schematically showing the overall structure of a conventional blow-by gas reducing apparatus. The blow-by gas returning device is provided with a blow-by gas passage 50 '(for example, a PCV hose) that connects the inside of the crankcase 9'with the intake passage 40'. A PCV valve 100 'is provided in the middle of the blow-by gas passage 50'. Reference numeral 200 denotes an atmosphere passage that allows the atmosphere to flow from the air cleaner 300 into the cam housing 400 to ventilate the inside and adjust the pressure in the crankcase 9 '. According to the above conventional blow-by gas returning apparatus, a closed loop is formed by connecting the intake passage 40 'and the inside of the crankcase 9'through the blow-by gas passage 50', and the PCV valve 100 'is provided. According to the pressure balance between the passage internal pressure (negative pressure) and the crankcase internal pressure, the blow-by gas blown into the crankcase 9'is returned to the intake passage 40 'and recombusted. Therefore, it is possible to suppress the blow-by gas from being mixed into the oil, and it is possible to suppress the deterioration of the oil and the generation of rust in the crankcase.

[Problems to be solved by the device]

However, in the above conventional blow-by gas returning apparatus, the PCV hose 5 that constitutes the blow-by gas passage is used.
0'is communicated with the intake passage 40 'through the outside of the engine. For this reason, it is necessary to consider the piping configuration of the PCV hose 50 'at the time of assembling, the layout freedom in the engine room reduces the design flexibility, and the PCV hose installation complicates the structure. It was a thing. Furthermore, since the PCV valve 100 'and the PCV hose 50' are structured to be exposed to the running wind and the cool air from the cooling fan, the blow-by gas is cooled while passing through the PCV hose 50 ', and the water content in the blow-by gas is reduced. PC condensed
It may adhere to the inner wall of the V-hose or the valve body of the PCV valve. When the engine is stopped while the condensed water is generated in this way, carbon and deposits in the blow-by gas are absorbed and accumulated in the condensed water, or the condensed water freezes to fix the PCV valve valve body, and It may cause malfunction. Therefore, an object of the present invention is to avoid freezing of the PCV valve without complicating the structure of the blow-by gas reducing apparatus.

[Means for Solving the Problems]

Therefore, the present invention takes the following means in order to solve the above problems. That is, referring to FIG. 1 of the present invention as an example, a blow-by gas passage (50) that connects the inside of the crankcase (9) and the intake passage (40) is provided, and the PCV valve (50) is provided in this blow-by gas passage (50). 100), the blow-by gas returning device for an engine is characterized in that the blow-by gas passage (50) includes a cylinder (11).
First penetrating a cylinder block (10) formed with
And a second passage (52) through the cylinder head (30) defining the upper surface of the combustion chamber (4).
Between the first passage and the second passage, a cylinder block (1
0) and the cylinder head (30) mating surface (80)
And a mating surface portion (80) of the head gasket (8) which is inserted in the
A PCV valve insertion hole (90) is formed in the
The PCV valve (100) is inserted in the valve insertion hole (90).

[Action]

During engine operation, blow-by gas blown from the combustion chamber (4) into the crankcase (9) flows in the first passage (51), the passage passing through the head gasket, and the second passage (52). Then, it is returned to the intake passage (40) and re-combusted in the combustion chamber. At this time, the PCV valve (100) operates by the pressure balance between the intake passage internal pressure and the crankcase internal pressure, and the first
Of the passage (51) and the second passage (52), that is, the cylinder block (10) and the cylinder head (3).
The passage area of the blow-by gas passage (50) is adjusted at the mating surface portion (80) with (0). Further, the connecting portion between the PCV valve (100) and the blow-by gas passage (50) is sealed by the head gasket (8). When the engine stops, the generation of blow-by gas due to combustion and the intake operation of the engine cease, so the flow of the blow-by gas containing water from the crankcase (9) to the intake passage (40) also stops, and the PCV valve (100).
The water remaining in the blow-by gas passage (50) and its vicinity are evaporated by the residual heat in the vicinity of the combustion chamber (4).

【Example】

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are longitudinal sectional views showing a main part of a blow-by gas reducing apparatus according to an embodiment of the present invention, and FIG. 1 is a view showing the entire structure of the blow-by gas reducing apparatus, FIG. FIG. 6 is a diagram specifically showing an assembled state of a PCV valve. In FIG. 1, reference numeral 10 is a cylinder block, and a piston 1 is provided inside a cylinder 11. The piston 1 reciprocates in the vertical direction in the figure as the crankshaft 2 rotates. A piston ring 3 slides on the cylinder wall surface 12 and suppresses blow-by gas from blowing out from the combustion chamber 4. Reference numeral 20 is an intake manifold, and a fuel supply device (not shown) such as a carburetor is attached upstream. 30 is a cylinder head, which defines the upper surface of the combustion chamber 4. Reference numeral 5 denotes an intake port formed in the cylinder head 30, which constitutes an intake passage 40 together with the intake manifold wall surface 21. Reference numeral 6 denotes an intake valve, which is interposed between the intake port 5 and the combustion chamber 4 and reciprocates in the axial direction of the intake shaft 5 as the cam shaft (not shown) rotates to open and close the intake port 5. Reference numeral 7 denotes a water jacket formed inside the cylinder block 10 and the cylinder head 30, through which cooling water circulates. Reference numeral 8 is a head gasket interposed between the cylinder block 10 and the cylinder head 30, and serves as a seal member between the cylinder block 10 and the cylinder head 30 such that combustion gas in the combustion chamber 4 and cooling water in the water jacket 7 are provided. Prevent leakage. Reference numeral 9 denotes a crankcase, which is a lower portion 13 of the cylinder block.
And the oil pan 14. Reference numeral 50 denotes a blow-by gas passage. The blow-by gas passage 50 includes a first passage 51 that penetrates the cylinder block 10 in the vertical direction in the drawing, a second passage 52 that penetrates the cylinder head 30, and a passage of both passages. It is composed of a passage that penetrates the head gasket 8 between them. The blow-by gas passage 50 is configured to connect the inside of the crankcase 9 and the intake passage 40, and in the present embodiment, is connected to the inside of the intake passage 40 via the passage 22 formed in the intake manifold 20. . Reference numeral 60 denotes an oil separator provided at the first passage inlet portion 51a. By providing a fin 61 and an oil drop hole 62 inside, an oil separator mixed in the blow-by gas flowing from the inside of the crankcase 9 is separated. , With the function of returning to the crankcase 9. Reference numeral 70 denotes a guide pipe provided in the intake passage side opening 23 of the passage 22 and defines the outflow direction of the blow-by gas returned into the intake passage 40. A PCV valve insertion hole 90 is formed in a connecting portion of the first passage 51 and the second passage 52, that is, a mating surface portion 80 between the cylinder block 10 and the cylinder head 30, and the PCV valve insertion hole 90 is formed in the PCV valve insertion hole 90. PCV valve 1
00 is installed. The specific structure and assembly structure of the PCV valve 100 will be described with reference to FIG. The PCV valve insertion hole 90 is formed in the cylinder block upper surface 15 and is formed in the first passage upper end portion 51b. The PCV valve 100 includes a casing 110 fitted in the PCV valve insertion hole 90, a valve body 120, and a spring 130 for biasing the valve body 120. The casing 110 includes the first member 111 and the second member 11
The blow-by gas inflow hole 113 is formed below the first member 111 and communicates with the first passage 51. The second member 112 is fitted to the first member 111,
The valve body 12 constitutes the seat surface of the spring 130.
Form a metering orifice with zero. The valve body tip 121 is formed in a tapered shape, and is configured to adjust the passage area of the blow-by gas passage 50 as it moves in the vertical direction. A head gasket 8 is provided on a mating surface portion 80 between the cylinder block 10 and the cylinder head 30. The head gasket 8 forms a seal between the cylinder block 10 and the cylinder head 30, and the PCV valve 100 is inserted into the PCV valve. It is fixedly supported in the hole 90. The operation of the first embodiment having the above configuration will be described. With the combustion of the engine, the cylinder wall 12 from the combustion chamber 4
Blow-by gas blows into the crankcase 9 through a gap between the piston 1 and the piston ring 3 or. The blow-by gas flows through the space in the crankcase 9 and then flows into the oil separator 60 due to the pressure balance between the intake passage internal pressure (negative pressure) and the crankcase internal pressure. Since the oil scattered in the crankcase 9 is mixed in the blow-by gas flowing into the oil separator 60, the oil separator 60
The oil is separated by the fin 61 and the oil drop hole 62 provided in the. The blow-by gas from which the oil has been removed flows into the first passage 51 that constitutes the blow-by gas passage 50, flows upward in the cylinder block 10 in FIG. 1, and is provided in the second passage 52 and the intake manifold 20. It is returned to the intake passage 40 through the open passage 22. Intake passage 40
The blow-by gas returned to the inside is again supplied into the combustion chamber 4 together with the air-fuel mixture supplied from the upstream side of the intake passage, and re-combusted. The flow rate of blow-by gas returned to the intake passage 40 is determined by the PCV valve 1 installed in the middle of the blow-by gas passage 50.
00 for metering. The PCV valve 100 has a casing 110 according to the pressure balance between the intake passage internal pressure (negative pressure) and the crankcase internal pressure.
The valve body 120 inserted inside moves, and the casing 110
The flow rate of the blow-by gas is adjusted by variably adjusting the passage area between the second member 112 and the valve element 120 that constitute the. That is, the intake passage internal pressure (negative pressure) increases at idle and at low load, and the valve body 120 is pulled upward in FIG. 2 in accordance with the intake passage internal pressure (negative pressure) and the crankcase internal pressure, thereby reducing the passage area. Make it smaller. Therefore,
The flow rate of the blow-by gas returned to the intake passage 40 becomes small. In addition, since the intake passage internal pressure (negative pressure) becomes smaller at medium and high loads than at idle and partial load,
The valve body 120 is pushed downward by the spring 130, increasing the passage area. Therefore, although the intake passage internal pressure (negative pressure) decreases, the flow rate of the blow-by gas returned to the intake passage 40 increases in combination with the crankcase internal pressure. In this way, the intake passage 40 is changed depending on the operating state of the engine.
The flow rate of blow-by gas returned to the inside is adjusted. In the present embodiment, since the first passage 51 and the second passage 52 forming the blow-by gas passage 50 are formed inside the cylinder block 10, the cylinder head 30, and the intake manifold 20, the PCV is provided outside the engine. There is no need to handle hoses. Therefore, since it is not necessary to set the piping configuration of the PCV hose or the like in consideration of the layout in the engine room, the degree of freedom in design can be increased, and the structure of the PCV hose can be complicated. Absent. Further, according to the present embodiment, the PCV valve 100 has the mating surface portion 80 between the cylinder block 10 in which the cylinder 11 is formed and the cylinder head 30 that defines the upper surface of the combustion chamber 4.
It is inserted in the PCV valve insertion hole 90 formed in the above. That is, since the PCV valve 100 is installed on the side of the combustion chamber 4, the crankcase 9 is stopped after the engine is stopped.
When the flow of the moisture-containing blow-by gas from the air to the intake passage 40 is stopped, the residual heat of the combustion chamber 4 is used to PC
V-valve 100 and blow-by gas passage 5 in the vicinity thereof
It is possible to evaporate the water remaining in the zero range and prevent the PCV valve from freezing regardless of the subsequent decrease in the engine temperature. Moreover, according to such an arrangement, the PCV valve 100 and the second passage 52 can be sealed by the head gasket 8 having a high sealing property for sealing the combustion gas from the combustion chamber 4, and the blow-by gas Leakage can be avoided. Further, since the blow-by gas passage 50 is formed in the entire engine body, the cylinder block 1
0, the cylinder head 30, and the cooling water in the water jacket 7 formed in the intake manifold 20, the temperatures of the PCV valve 100 and the blow-by gas passage 50 after the engine is warmed up can be maintained at a substantially constant temperature at all times. 3 to 5 are vertical sectional views showing a concrete structure of a PCV valve applied to a blow-by gas returning apparatus according to another embodiment of the present invention, and FIG. 3 is a PCV valve insertion hole 9
0 is formed in the cylinder head 30, and P is shown in FIG.
The CV valve insertion hole 90 is formed in both the cylinder block 10 and the cylinder head 30, and FIG. 5 eliminates the casing 110 in the embodiment of FIG. 1 and directly connects the spring 130 and the valve body 120 to the PCV valve insertion hole 90.
It is shown that each is inserted in. It should be noted that parts corresponding to FIGS. 1 and 2 are denoted by the same reference numerals, and a detailed description thereof will be omitted. The operation of the valve body 120 is also the same as that of the first embodiment described above, and therefore, will be described in detail. Description is omitted. As shown in these examples, the PCV valve insertion hole 90 is formed in the cylinder block 10 or the cylinder head 3.
The blow-by gas reducing device can be configured only by forming the mating surface portion 0 of 0 and inserting the PCV valve 100 in the PCV valve insertion hole 90. Therefore, the workability and the assembling workability are improved. You can measure. In addition, a structure in which a PCV valve is interposed near a water jacket formed in an intake manifold (for example, Japanese Utility Model Laid-Open No. 60-38109) or a structure in which a cooling water passage is arranged near the PCV valve (for example, Actual Kaisho 60
No. 173612), these devices do not have a structure that utilizes the sealing effect of the head gasket while utilizing the residual heat of the combustion chamber after the engine is stopped. Although the specific embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and various embodiments are included within the scope of the claims of the utility model. For example, the blow-by gas passage may not be opened to the intake manifold but may be opened directly to the intake port from the cylinder head.
In this case, in order to prevent the blow-by gas from flowing into a specific cylinder, it is desirable to connect the intake ports to each other so that the blow-by gas flows into each cylinder.

[Effect of device]

As described above, according to the present invention, the first passage penetrating the cylinder block in which the cylinder is formed, the second passage penetrating the cylinder head defining the upper surface of the combustion chamber, the first passage and the first passage. The PCV valve and the passage that penetrates the head gasket interposed between the mating surfaces of the cylinder block and the cylinder head between the two passages and the PCV valve are all arranged inside the engine, so the layout in the engine room is easy. become. Furthermore, since the connection portion between the blow-by gas passage and the PCV valve is sealed by using a head gasket having a high sealing property, which is conventionally used, it is possible to prevent the blow-by gas from leaking to the outside. Further, when the flow of the blow-by gas containing water from the crankcase to the intake passage is stopped after the engine is stopped, the residual heat in the combustion chamber is used to remain in the PCV valve and the blow-by gas passage in the vicinity thereof. Since the water content can be evaporated, the PCV valve can be prevented from freezing regardless of the subsequent decrease in engine temperature.

[Brief description of drawings]

1 and 2 are longitudinal sectional views showing a main part of a blow-by gas reducing apparatus according to an embodiment of the present invention. FIG. 1 is a view showing the entire structure of a blow-by gas reducing apparatus, and FIG. 3 is a vertical cross-sectional view showing a concrete structure of a PCV valve applied to a blow-by gas reducing apparatus according to another embodiment of the present invention. FIG. 3 is a diagram showing the structure of the PCV valve insertion hole formed in the cylinder head, and FIG. 4 is a diagram showing the structure of the PCV valve insertion hole formed in both the cylinder block and the cylinder head. FIG. 6 is a view showing the structure of a PCV valve valve body and a spring directly inserted in the PCV valve insertion hole, and FIG. 6 is a vertical cross-sectional view schematically showing the entire structure of a conventional blow-by gas reducing apparatus. 8 ... Head gasket 9 ... Crank case 10 ... Cylinder block 30 ... Cylinder head 40 ... Intake passage 50 ... Blow-by gas passage 51 ... First passage (Blow-by gas passage) 52 ... Second passage (Blow-by gas passage) 80 …… Mating surface (Cylinder block * Cylinder head) 90 …… PCV valve insertion hole 100 …… PCV valve 110 …… Casing 120 …… Valve body 130 …… Spring

Claims (1)

[Scope of utility model registration request] 1. A blow-by gas returning apparatus for an engine, wherein a blow-by gas passage is provided for communicating the inside of a crankcase with an intake passage, and a PCV valve is interposed in the blow-by gas passage. A first passage through the cylinder block, a second passage through the cylinder head defining an upper surface of the combustion chamber, and a first passage.
And a passage penetrating a head gasket interposed in the mating surface of the cylinder block and the cylinder head between the passage and the second passage, and a PCV valve insertion hole is formed in the mating surface. This PCV
A blow-by gas reduction device for an engine, wherein a PCV valve is provided in a valve insertion hole.