JPS6126571Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to the structure of a blow-by gas passage in an engine, and in particular to a blow-by gas passage formed in a cylinder block and a cylinder head so as to communicate between the inside of the crankcase and the inside of the head cover. Regarding the structure of gas passages.

(Prior art) Conventionally, in engines, blow-by gas in the crankcase has been
As disclosed in the above publication, the blowby gas is caused to flow into the head cover through the blowby gas passage formed in the cylinder block and the cylinder head, and the blowby gas that has flowed into the head cover is supplied to the intake passage of the engine, and the blowby gas is supplied to the engine intake passage. A so-called crankcase ventilation system (commonly known as the PCV system), which processes combustion, is used.

By the way, the blow-by gas passages of the cylinder block and cylinder head are subject to space constraints such that the exhaust passage and the spark plug are both disposed on one side (exhaust side) of the cylinder head.
In addition, due to the functional constraint of preventing the oil content in the blow-by gas from turning into tar due to the high temperature exhaust gas flowing through the exhaust passage, the intake passage is placed on the other side (intake side) of the cylinder head. ,
It is disposed vertically penetrating the cylinder block, and accordingly, the crankcase is also disposed on the other side (intake side) of the cylinder block so as to communicate with the lower part of the blow-by gas passage.

(Problem to be solved by the invention) Therefore, due to this arrangement structure, pressure due to the rotation of the crank side and the balancer shaft acts in the crankcase on the side where the blow-by gas passage is located, causing gas pressure to increase. This results in a large amount of oil mist contained in the blow-by gas in the crankcase. Moreover, since the blow-by gas passages between the cylinder block and the cylinder head are formed in direct communication, the blow-by gas containing a large amount of oil mist directly flows upward into the head cover through the blow-by gas passage, and flows into the head cover. Even if an oil separator is provided, the oil component cannot be separated sufficiently, and a large amount of oil mist is supplied to the intake passage along with blow-by gas, resulting in a problem that oil consumption increases.

The present invention has been developed in view of these points, and its purpose is to make the oil mist collide with the buttful wall, and also to make the blow-by gas containing the remaining oil mist collide with the wall surface, and reduce the flow velocity. By separating and collecting a large amount of oil mist in the blow-by gas,
The purpose is to reduce the rise of oil mist into the head cover.

<Means for Solving the Problems> In order to achieve the above object, the solution of the present invention is to direct the blow-by gas in the crankcase to an opening in the crankcase where the balancer shaft is installed at one end and a cylinder at the other end. In an engine in which the blowby gas flows into the head cover through a blowby gas passage that opens at the top of the head, and the blowby gas that has flowed into the head cover is supplied to the intake passage of the engine, a blowby gas is supplied to the crankcase opening in the blowby gas passage. A structure in which a wall is provided, an expansion chamber is provided in the blowby gas passage downstream of the buttful wall, and the opening of the blowby gas passage to the expansion chamber is shifted between the upstream side and the downstream side to form the blowby gas passage into a substantially crank shape. That is.

(Function) With the above configuration, in the present invention, the oil mist stirred up by the rotation of the counterweight of the crankshaft and the balancer shaft first collides with the buff-full wall, thereby causing the oil mist to flow into the blow-by gas passage. This prevents the influx of Furthermore, the blow-by gas containing oil mist whose inflow could not be completely blocked by the above-mentioned butt-full wall passes through the expansion chamber and the blow-by guy passage formed in the shape of a crank. The oil mist collides successfully with the inner wall of the passage, and the blow-by gas is retained in the expansion chamber, reducing its flow velocity, and the oil mist in the blow-by gas is thoroughly separated.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

In FIGS. 1 to 4, 1 is a cylinder block, 2 is a cylinder head, and 3 is a head cover that covers the cylinder head 2. The cylinder block 1 includes a plurality of cylinders 4, 4... are formed, and water jackets 5, 5 are formed on both sides of the cylinders 4, 4.... Although not shown, one exhaust side of the cylinder head 2 (left side in Figure 1)
An exhaust passage and a spark plug are disposed on the side, and an intake passage is disposed on the intake side (right side in FIG. 1).

Furthermore, a crankcase 6 is formed to bulge on the intake side (on the right side in FIG. 1) at the bottom of the cylinder block 1, and a balancer shaft (not shown) is installed inside the crankcase 6. On the intake side of the head 2, there are a plurality of blow-by gas passages 7, one end of which opens into the crankcase 6 and the other end of which opens into the upper part of the cylinder head 2, communicating the inside of the crankcase 6 and the inside of the head cover 3. , 7... are formed to penetrate vertically. Further, an oil separator 8 is disposed in the upper part of the head cover 3 to separate the oil component in the blow-by gas and allow only the blow-by gas to flow. The intake passage 10 is connected to the downstream side of the throttle valve 11 . As described above, the blow-by gas in the crank case 6 is caused to flow into the head cover 3 through the blow-by gas passages 7, 7, . Blowby gas supply passage 9
A so-called crankcase ventilation system is configured in which the air is supplied to the intake passage 10 downstream of the throttle valve 11 via the air intake passage 10, and is burned in the engine. 12 is a PVC (Positivc Crankcase) installed in the blow-by gas supply passage 9.
Ventilation) valve, which reduces the opening degree when the intake negative pressure in the intake passage 10 downstream of the throttle valve 11 is large;
The opening degree is increased when the intake negative pressure is low, and the amount of blow-by gas supplied to the engine is controlled in accordance with the operating state of the engine.

As a feature of the present invention, each of the blow-by gas passages 7 provided in the cylinder block 1 and the cylinder head 2 opens into the crankcase 6 through an expansion chamber 13 at the lower part thereof, and the opening portion thereof A baffle wall 14 is integrally provided on the cylinder block 1 at a portion facing the blow-by gas passage 7 so as to cover the portion, and thus an upstream opening 7a of the blow-by gas passage 7 to the expansion chamber 13 is provided. and the downstream opening 7b are shifted in the direction of the crankshaft, and are formed into a substantially crank shape formed by the expansion chamber 13. Further, the buff-full wall 14 faces a counterweight (not shown) of the crankshaft, and therefore the opening 7a is offset in the direction of the crankshaft with respect to the counterweight.

Next, to describe the operation of the above embodiment, since the crankcase 6 is disposed on the intake side of the cylinder block 1 (on the right side in FIG. 1), the rotation of the crankshaft and balancer shaft is (The direction of rotation is indicated by arrow X)
As a result, the gas pressure in the crankcase 6 on the side where the blow-by gas passage 7 is located is high, and the blow-by gas in the crank case 6 contains a large amount of oil mist. Of these oil mist, the oil mist that is stirred up by the rotation of the crankshaft counterweight and balancer shaft projects into the opening of each blowby gas passage 7 to the crankcase 6 that faces the blowby gas passage 7. Since the oil mist collides with the provided buff-full wall 14, it is possible to prevent the oil mist from directly flowing into the blow-by gas passage 7.

Further, the blow-by gas containing oil mist whose inflow could not be completely blocked by the baffle wall 14 flows into the cylinder block 1 and the cylinder head 2.
When flowing into the head cover 3 through the blow-by gas passages 7, 7..., the blow-by gas passages 7, 7...
An upstream opening 7a and a downstream opening 7b of the blow-by gas passage 7 to the expansion chamber 13 at the lower part of the
Since these are offset in the crankshaft direction to form a substantially crank-shaped passage, the upward flow of the high-pressure blow-by gas flows into the blow-by gas passage 7 while effectively colliding with the inner wall of the crank-shaped passage. At the time of this collision, most of the oil mist in the blow-by gas is separated from the gas flow and collected due to the difference in inertial mass, and is passed from the upstream opening 7a through the crankcase 6 to the oil pan (not shown). Go back inside. Therefore, oil mist contained in the blow-by gas in the crankcase 6 can be reliably prevented from rising into the head cover 3.
After that, the oil component of the blow-by gas that has flowed into the head cover 3 is separated by an oil separator 8, and then supplied to the downstream of the throttle valve 11 in the intake passage 10 via the blow-by gas supply passage 9, where it is combusted by the engine. However, when the oil mist passes through the oil separator 8, the remaining oil mist that rises without being collected due to the collision with the inner wall of the crank-shaped passage is separated and collected and sent to the oil pan (not shown) via the blow-by gas passage 7. ), so the intake passage 1
The blow-by gas supplied to the engine 0 contains almost no oil mist, and the amount of oil consumed can be significantly reduced.

Furthermore, the flow velocity of the blow-by gas is slowed down due to the collision with the buff-full wall 14. Furthermore, since the crank-shaped passage is constituted by the expansion chamber 13, when the blow-by gas whose flow rate has been reduced flows through the crank-shaped passage (expansion chamber 13), it stagnates and the flow rate becomes even slower. Coupled with the collision with the inner wall of the crank-shaped passage, the oil mist collection effect is further enhanced, the rise of oil mist into the head cover 3 can be further reduced, and the separation ability of the oil separator 8 is further improved. It can be reduced.

In the above embodiment, the lower part of the blow-by gas passage 7, that is, the opening 7a to the crankcase 6
Although the vicinity is formed into a substantially crank shape, any part in the middle of the blow-by gas passage 7 may be formed into a substantially crank shape, and the same effects as in the above embodiment can be achieved.

(Effects of the invention) As described above, according to the invention, in an engine equipped with a crankcase ventilation system, a blow-by gas passage provided in a cylinder block and a cylinder head is provided with a buff-full wall,
By forming the middle of the blow-by gas passage downstream of the buff-full wall into a substantially crank shape, it is possible to significantly reduce the rise of oil mist into the head cover, and it is possible to reduce oil consumption. .

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the invention, FIG.
2 is a plan view of the cylinder block, FIG. 3 is a sectional view taken along the line - in FIG. 1, and FIG. 4 is a sectional view taken along the line - in FIG. 3. DESCRIPTION OF SYMBOLS 1... Cylinder block, 2... Cylinder head, 3... Head cover, 6... Crank case, 7... Blow-by gas passage, 7a... Upstream opening, 7b... Downstream opening, 10... Intake Passageway, 13... Expansion room, 14... Full wall.

Claims (1)

[Scope of utility model registration request] The blow-by gas in the crank case is caused to flow into the head cover through a blow-by gas passage that opens in the crank case where the balancer shaft is installed and the other end opens in the upper part of the cylinder head, and the blow-by gas that flows into the head cover is removed. In an engine configured to supply gas to an intake passage of the engine, a buff-full wall is provided at the crankcase opening in the blow-by gas passage, an expansion chamber is provided in the blow-by gas passage downstream of the buff-full wall, and gas is supplied to the expansion chamber. A structure of a blowby gas passage for an engine, characterized in that the opening of the blowby gas passage is shifted between the upstream side and the downstream side to form the blowby gas passage into a substantially crank shape.