JPS6314011Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a blowby gas reducing device for introducing blowby gas discharged from inside an engine body into an intake system.

<Conventional technology> When blow-by gas is discharged from inside the engine body, it is recommended to return it to the engine intake system instead of exhausting it to the outside in consideration of the effect of unburned HC contained in the gas on the human body. I have to.

<Problems to be solved by the invention> However, since blow-by gas passes through an ambient atmosphere containing extremely large amounts of oil droplets, the gas contains a large amount of oil mist. For this reason, if the oil is returned to the intake system as it is, the oil will be carried away and the amount of oil consumed will increase. Further, problems such as deterioration of engine combustion performance and deterioration of exhaust performance etc. occur.

This idea was made in view of the above circumstances.
An object of the present invention is to provide a blow-by gas reducing device that can effectively separate oil from blow-by gas.

<Means for Solving the Problems> For this reason, the present invention provides an expansion chamber in the middle of the blow-by gas passage which is provided in the rocker cover and opens into the rocker cover at both ends, and the opening end of the blow-by gas passage on the side of the expansion chamber is While the blowby gas passage and the intake manifold are configured to face each other, the blowby gas passage side open end of the communication passage that communicates the blowby gas passage and the intake manifold is made to face an expansion chamber wall surface that protrudes outward from the blowby gas passage surface and is located near the wall surface. In addition, the bottom wall of the expansion chamber is provided with an opening that opens into the inner space of the rocker cover.

<Operation> According to the above configuration, the blowby gas that has flowed into the blowby gas passage has its flow velocity reduced in the expansion chamber, and its flow direction is reversed when it flows into the communication passage. Oil can be separated from blow-by gas by force action. Furthermore, the separated oil can be returned to the engine body.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is an overall schematic diagram of the blow-by gas reduction apparatus of this embodiment. In the figure, blow-by gas introduced into the breather 2 from within the crankcase at the bottom of the engine body 1 is introduced into the rocker cover 3 through a communication path 4 that communicates between the breather 2 and the rocker cover 3. Furthermore, it flows into the blow-by gas passage 9 (described later) formed in the rocker cover 3,
After the oil in the gas is separated in the gas passage 9, it is introduced into the intake manifold 6 via the communication passage 7 that communicates the gas passage 9 and the intake manifold 6, and is returned to the combustion chamber for combustion. It is becoming more and more common.

Next, FIGS. 2 and 3 show the structure of the oil separation section, which is the main part of this blow-by gas reduction device.

In the figure, a partition plate 8 that partitions the inner space of the rocker cover 3 is fixed to the inner wall of the rocker cover 3, and the aforementioned blow-by gas passage 9, which is open at both ends, is formed by the partition plate 8 and the inner wall of the rocker cover 3. An expansion chamber 10 for separating blow-by gas and oil is provided at an intermediate position of the gas passage 9, and the opening ends of the blow-by gas passage 9 on the expansion chamber 10 side face each other. Further, an expansion chamber bottom wall 10 protrudes downward from the bottom wall 9a of the blow-by gas passage 9.
A is provided with a notch, and the notch and the inner wall of the rocker cover 3 form a drain hole 11 for returning separated oil to the engine body. and,
One end of a communication passage 7 communicating with the intake manifold 6 protrudes into the expansion chamber 10 from the top wall of the rocker cover 3. The opening end of the communicating passage 7 that has entered is located opposite to the bottom wall 10a of the expansion chamber, and the bottom wall 1
It extends to near 0a.

In this configuration, the blow-by gas introduced into the rocker cover 3 from inside the crankcase via the breather 2 and the communication path 4 is transferred to the rocker cover 3.
The blow-by gas flows into the passage 9 from both ends of the blow-by gas passage 9 formed therein as shown by the arrows in FIG.
Each flows toward the expansion chamber 10 in the middle of the passage. When the blow-by gas enters the expansion chamber 10, the gas flows flowing in from both sides collide with each other, causing turbulence in the gas flow and causing oil droplets to adhere to the surrounding wall surface. Furthermore, since the blow-by gas flow cross-sectional area is expanded, the gas flow rate is reduced. Therefore, oil droplets fall onto the bottom wall 10a of the expansion chamber 10 due to the specific gravity contained in the blow-by gas. Further, the blow-by gas that has entered the expansion chamber 10 descends toward the bottom wall 10a of the expansion chamber facing the open end of the communication path 7, as shown by the arrow in FIG.
It turns around nearby and flows into the communication path 7. During this reversal of the blow-by gas, oil droplets with a large mass contained in the gas are separated from the gas by centrifugal force and fall onto the bottom wall 10a of the expansion chamber. The oil that has fallen onto the bottom wall 10a of the expansion chamber is returned to the engine body through the drain hole 11. In this way, the oil droplets in the blow-by gas are separated by the turbulence of the gas flow, the reduction in the gas flow rate, and the action of centrifugal force, making it possible to perform oil separation very effectively. Therefore, almost no oil is carried away by the blow-by gas introduced into the intake manifold 6 through the communication passage 7, and oil consumption can be significantly reduced. Further, since oil droplets do not enter the intake manifold 6, deterioration of combustion performance and exhaust performance can be prevented.

As described above, according to the present invention, the flow rate of the blowby gas is reduced in the expansion chamber provided in the blowby gas passage in the rocker cover.
Oil droplets with heavy specific gravity fall on the bottom wall of the expansion chamber and can be separated from the blow-by gas. Further, since the flow of the blowby gas is reversed and blowby gas flows into the communication path that communicates the blowby gas path and the intake manifold, the oil can also be separated by the action of centrifugal force at the time of reversal. In addition, the blow-by gas flows flowing into the expansion chamber from both sides collide with each other and cause large turbulence in the gas flows, making it easier for oil mist to adhere to the wall surface. In this way, oil droplets can be effectively separated from the blow-by gas by the three effects of reducing the gas flow velocity, centrifugal force, and generating turbulence due to collision of gas flows. Therefore, since the blow-by gas introduced into the combustion chamber through the intake manifold contains almost no oil, deterioration of combustion performance and exhaust performance can be prevented.

Furthermore, since the separated oil can be returned to the engine body through the opening in the bottom wall of the expansion chamber, oil consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention;
FIG. 2 is a perspective view of a main part of the same embodiment, and FIG. 3 is a longitudinal sectional view of a blow-by gas passage. 3...Rotsuka cover, 6...Intake manifold,
7... Communication path, 8... Partition plate, 9... Blow-by gas passage, 10... Expansion chamber, 10a... Bottom wall of expansion chamber, 11... Drain hole.

Claims (1)

[Scope of utility model registration request] An expansion chamber is provided in the middle of a blow-by gas passage that is provided in the rocker cover and has both ends opening into the rocker cover, and the open ends of the blow-by gas passage on the side of the expansion chamber face each other, while the blow-by gas passage and the intake manifold The opening end on the blow-by gas passage side of the communication passage communicating with the blow-by gas passage is made to face the wall surface of the expansion chamber that protrudes outward from the wall surface of the blow-by gas passage and protrudes into the vicinity of the wall surface, and the bottom wall of the expansion chamber is connected to the space inside the rocker cover. A blow-by gas reduction device characterized by having an opening to open.