JPH0332733Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine blow-by gas recirculation passageway used to recirculate blow-by gas leaking from the combustion chamber from within the cylinder head cover to the intake system. be.

[Prior art] Many HCs are contained in the so-called blow-by gas that leaks from the combustion chamber of the engine into the crankcase.
Not only does it contain oil, but also the mist-like oil floating in the crankcase is mixed together. Therefore, in modern automobile engines, blow-by gas is not directly released into the atmosphere, but is first guided to an oil separation chamber installed at the top of the cylinder head cover, and the oil content is removed in the oil separation chamber. After separation, the blow-by gas is returned to the intake system through a recirculation passage.
At this time, in order to prevent a decrease in output, it is common to provide a throttle in the blow-by gas recirculation passage to return the blow-by gas to the intake system little by little.

As an embodiment of providing a throttle in the blow-by gas recirculation passage, for example,
As shown in Publication No. 66212, a small-diameter connection port protruding from the outside of the cylinder head cover on the oil separation chamber side is provided with a throttling function, and a blow-by gas hose extending from the intake side is connected to the connection port. As shown in Fig. 3, the cylinder head cover a has a small diameter throttle hole c that opens on the inner wall surface b of the cylinder head cover a, and a large diameter connection that opens on the outer wall surface d of the cylinder head cover a. It is known that holes e are provided in communication with each other, a tubular connecting member f is press-fitted into the connecting hole e, and a blow-by gas hose g is connected to the connecting member f.

[Problems to be solved by the invention] However, in the conventional type, since the opening end surface of the throttle hole c coincides with the inner wall surface b of the cylinder head cover a, as shown in FIG. e
If the connecting portion having the cylinder head cover a must be provided in a substantially horizontal direction, problems are likely to occur in cold weather. That is, when the cylinder head cover a is cooled by outside air when the engine is stopped, some of the moisture in the blow-by gas inside the cylinder head cover a condenses and adheres to the inner wall surface b of the cylinder head cover a. do. When the water droplet h falls down the inner wall surface b, it easily enters the aperture hole c and remains therein. Therefore, in winter, etc., the aperture hole c
The water accumulated inside may freeze and completely block the throttle hole c. As a result, there is a problem in that the blow-by gas cannot be refluxed until the frozen state is resolved.

In addition, with such a configuration, oil adhering to the inner wall surface b of the cylinder head cover a enters the throttle hole c when falling along the inner wall surface b.
There is a problem in that the gas is carried out from the blow-by gas passage into the intake system and is consumed.

[Means for solving the problem] Therefore, in order to solve this problem, the present invention connects the end of the blow-by gas recirculation passage on the cylinder head cover side to a bottomed cylindrical connection having a throttle hole in the end wall. The connecting member is placed close to the rounded portion between the side wall and the top wall of the cylinder head cover, and penetrates the side wall in a substantially horizontal position so that the end wall portion thereof is connected to the inner wall surface of the cylinder head cover. The connecting member is characterized in that it protrudes further inward and the amount of protrusion is smaller than the inner diameter of the connecting member.

[Function] With this structure, the blow-by gas guided into the cylinder head cover from the inside of the crankcase etc. is transferred to the bottomed cylindrical connecting member having the throttle hole attached to the cylinder head cover. The blow-by gas is supplied to the intake system in small quantities through the blow-by gas recirculation passage starting from the cylinder head cover. Even if water droplets adhering to the inner wall surface of the cylinder head cover fall down the wall surface, it is difficult for the water droplets to enter the throttle hole. Therefore, it is possible to prevent water from accumulating in the aperture and freezing.

Further, since the connecting member is held in a substantially horizontal position on the side wall in proximity to the rounded portion, the throttle hole is located close to the top surface within the cylinder head cover. However, at such a high position, there is very little oil mist in the blow-by gas, so it is effective to carry out oil adhering to the inner wall surface and floating oil mist from the throttle hole to the intake system. It can also be suppressed.

Furthermore, the amount of oil mist inside the cylinder head cover increases toward the center and decreases toward the periphery. Therefore, if the end wall of the connecting member is made to protrude into the cylinder head cover and the amount of protrusion is made smaller than the inner diameter of the connecting member, water droplets and oil adhering to the inner wall surface will enter the throttle hole. Not only can it prevent
Blow-by gas can be returned to the intake system from near the inner wall surface where there is less oil mist.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, 1 is a cylinder block of an engine, and 2 is a cylinder head fastened onto this cylinder block 1. An intake system 3 and an exhaust system 4 are connected to the side surface of the cylinder head 2. The intake system 3 passes the atmosphere through an air cleaner 3a to a vaporizer 3.
b, and the air-fuel mixture produced in the carburetor 3b can be guided into the combustion chamber through an intake pipe 3c and an intake port (not shown). Also,
A cylinder head cover 5 is attached to the upper opening of the cylinder head 2, and a blow-by gas G is attached to one side of the top of the cylinder head cover 5.
An oil separation chamber 6 is formed to extract the oil contained therein. Then, blow-by gas G in the crankcase (not shown) flows into the cylinder block 1.
The oil is guided into the cylinder head cover 5 through a port provided in the cylinder head 2 and led to the oil separation chamber 6.

The oil separation chamber 6 and the inside of the air cleaner 3a of the intake system 3 are communicated through a blow-by gas recirculation passage 7. The end of the blow-by gas recirculation passage 7 on the cylinder head cover side is constituted by a connecting member 8. The connecting member 8 is connected to the end wall 8
It has a cylindrical shape with a bottom and has a throttle hole 8a in b, and is fixed to the cylinder head cover 5 in a substantially horizontal position, with its end wall 8b being located inside the inner wall surface 5c of the cylinder head cover 5. It's made to stick out. That is, as shown in FIG. 2, the oil is applied to the side wall 5a in close proximity to the radiused portion 5e formed at the boundary between the side wall 5a and the top wall 5d of the cylinder head cover 5, but not over the radiused portion 5e. A mounting hole 5b communicating with the separation chamber 6 is bored approximately horizontally, and the connecting member 8 is inserted into the mounting hole 5b until the end wall 8b thereof protrudes inward by a distance l from the inner wall surface 5c. It is press-fitted and fixed. Here, the protrusion amount l of the end wall 8b is made smaller than the inner diameter of the connecting member 8, as shown in FIG.
A starting end 9a of a blow-by gas hose 9 communicating with the internal space of the air cleaner 3a is connected to the oil separation chamber 6 via this connecting member 8. That is, a projection 8c for preventing slippage is formed at the outer end of the connecting member 8, and the starting end of the blow-by gas hose 9 is fitted onto the outer periphery of the outer end.

With this configuration, the blowby gas G from which oil has been removed in the oil separation chamber 6 of the cylinder head cover 5 is fed to the intake system 3 through the blowby gas recirculation passage 7 constituted by the connecting member 8 and the blowby gas hose 9. The air is guided into the space within the air cleaner 3a that forms the starting end, and is again guided into the combustion chamber through the intake system 3. The recirculation amount of the blow-by gas G is suppressed to an appropriate value by the throttling action of the throttling hole 8a provided in the end wall 8b of the connecting member 8.

In this way, the blowby gas G is recirculated, and as described above, the blowby gas recirculation passage 7 has the end wall 8b of the connecting member 8 projecting inward from the inner wall surface 5c of the cylinder head cover 5. There is. Therefore, the cylinder head cover 5
Even if water droplets W adhering to the inner wall surface 5c fall down the inner wall surface 5c, it is difficult for the water droplets W to enter the aperture hole 8a.
Therefore, it is possible to prevent water from accumulating and freezing inside the aperture hole 8a. Therefore, it is possible to eliminate the inconvenience that the blow-by gas recirculation passage 7 is clogged during cold weather and the blow-by gas G is not recirculated properly.

Further, the throttle hole 8a is located at the inner surface of the top wall 5d, in other words, at a position close to the upper surface 5f within the cylinder head cover 5. However, at such a high position, the amount of oil mist in the blow-by gas is at its lowest. For this reason, the inner wall surface 5c
It is possible to effectively suppress oil mist in the blow-by gas from being carried out from the throttle hole 8a to the intake system, as well as oil falling through the air, and oil consumption can be effectively reduced.

Furthermore, looking at the distribution of oil mist within the oil separation chamber 6, there is a tendency for the oil mist to be larger toward the center of the oil separation chamber 6 and to be smaller toward the inner wall surface 5c and upper surface 5f of the periphery. Therefore, the end wall 8
If the protrusion amount l of b is made smaller than the inner diameter of the connecting member 8, water droplets W and oil attached to the inner wall surface 5c can be effectively prevented from entering the throttle hole 8a, and oil mist can be reduced. The blow-by gas G can be returned from the region to the intake system, and oil mist can be effectively prevented from being carried to the intake system 3.

Further, the bottomed cylindrical connecting member 8 having the aperture hole 8a in the end wall can be easily manufactured by press drawing or drawing from a pipe. On the other hand, if such a connecting member 8 is used, it is only necessary to provide a simple mounting hole 5b whose inner diameter does not change on the cylinder head cover 5 side.Therefore, as shown in FIG. The machining process can be reduced compared to conventional products in which the cylinder head cover a must be provided on the side of the cylinder head cover a. Therefore, as a result, manufacturing can be simplified more easily than the conventional one, and costs can be reduced.

The shape of the connecting member is, of course, not limited to that of the embodiment described above, and various modifications can be made without departing from the spirit of the present invention.

[Effects of the invention] Since the present invention has the above-mentioned configuration, it is possible to effectively prevent the blockage of the throttle hole due to freezing of water droplets with a simple and easy-to-manufacture structure, and it is possible to always ensure reliable blow-by gas flow. It is possible to provide a blow-by gas reflux passage that allows reflux to occur.

Furthermore, the throttle hole protrudes inward from the inner wall surface of the cylinder head cover, and is opened at a position within the cylinder head cover where there is very little oil mist, so that oil and oil mist adhering to the inner wall surface are removed. It is possible to effectively prevent the air from being taken out from the throttle hole into the intake system and consumed.

Furthermore, since the aperture hole has a dimension smaller than the inner diameter of the connecting member and projects inward from the inner wall surface, it is possible to not only prevent water droplets and oil adhering to the inner wall surface from entering the aperture hole. ,
Blow-by gas can be returned to the intake system from a region with little oil mist, and oil consumption can be effectively suppressed.

[Brief explanation of the drawing]

FIG. 1 is a schematic overall explanatory diagram showing one embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part showing a connecting member portion in the same embodiment. FIG. 3 is a sectional view corresponding to FIG. 2 showing a conventional example. 3...Intake system, 5...Cylinder head cover,
5a...Side wall, 5c...Inner wall surface, 5d...Top wall,
5e...Round portion, 5f...Top surface, 7...Blowby gas recirculation passage, 8...Connection member, 8a... Throttle hole, 8b...End wall, 9...Blowby gas hose.

Claims (1)

[Scope of utility model registration request] In the blowby gas recirculation passage that recirculates the blowby gas in the cylinder head cover to the intake system, the end on the cylinder head cover side is constituted by a bottomed cylindrical connecting member having a throttle hole in the end wall, and this connecting member is brought close to the rounded portion between the side wall and the top wall of the cylinder head cover, and penetrates the side wall in a substantially horizontal position so that its end wall portion protrudes inward from the inner wall surface of the cylinder head cover, and the amount of protrusion thereof. A blow-by gas recirculation passage characterized in that the inner diameter of the connecting member is smaller than the inner diameter of the connecting member.