JPH0629457Y2 - Blow-by gas reduction device for internal combustion engine - Google Patents

Description

The present invention relates to a blow-by gas returning apparatus for an internal combustion engine, and more particularly to an improvement of a blow-by gas returning apparatus for an internal combustion engine having a cylinder head for each pair of cylinders such as a V-type engine. .

2. Description of the Related Art For example, as a blow-by gas reducing device in a V-type engine, a device described in US Pat. No. 3,661,128 is known. The structure of this blow-by gas reducing apparatus will be described with reference to FIG. 5. Reference numeral 1 denotes an internal combustion engine body, and the internal combustion engine body 1 has a first cylinder group 3 and a second cylinder group 4 arranged in a V shape. And the oil pan 6 that is fixed to the lower end of the cylinder block 2 and separates the crankcase 5.
A first cylinder head 7 and a second cylinder head 8 provided for each of the cylinder groups 3 and 4 and fixed to the upper end of the cylinder block 2, respectively, and a first rocker for covering the upper surfaces of these cylinder heads 7 and 8. It has a cover 9 and a second rocker cover 10. To the intake ports of the first and second cylinder heads 7 and 8, branch portions 12 and 13 branched from the intake collector portion 11 are connected as a part of the intake passage. The intake collector section 11 includes the intake passage 1
4 is connected to the air cleaner 15 and a throttle valve 16 is interposed between the two. Incidentally, 17 and 18 are exhaust manifolds connected to the first and second cylinder heads 7 and 8, respectively.

A first blow-by gas passage 19 is formed in the cylinder block 2 and the first cylinder head 7 along the axial direction of the first cylinder group 3, and the inside of the first cylinder head 7 is formed by the first blow-by gas passage 19. And the crankcase 5 are in communication with each other. Similarly, a second blow-by gas passage 20 extending from the second cylinder head 8 to the cylinder block 2 along the axial direction of the second cylinder group 4 is formed, and the second blow-by gas passage 20 forms a second cylinder. The interior of the head 8 and the crankcase 5 are communicated with each other. One end of the scavenging passage 21 is connected to the upper surface of the first rocker cover 9 and the other end thereof is connected to the intake passage 14 upstream of the throttle valve 16, whereby the intake passage 14 upstream of the throttle valve 16 is connected. The side communicates with the inside of the first cylinder head 7. Further, one end of the blow-by gas recirculation passage 22 is connected to the upper surface of the second rocker cover 10, and the other end thereof is connected to the downstream side of the throttle valve 16 of the intake passage 14, specifically, the intake collector portion 11, As a result, the downstream side of the throttle valve 16 and the inside of the second cylinder head 8 are in communication. A blow-by gas control valve 23 for controlling the passage area of the blow-by gas recirculation passage 22 is interposed in the blow-by gas recirculation passage 22. In addition, inside the first rocker cover 9 and the second rocker cover 10 to which the scavenging passage 21 and the blow-by gas recirculation passage 22 are connected, a baffle plate 24 for separating the lubricating oil so as to cover these openings. , 25 are provided. As shown in FIG. 6, the blow-by gas control valve 23 has a structure in which a valve body 26 is opposed to an orifice 27 and supported by a spring 28, and the pressure on the downstream side of the throttle valve 16, that is, the intake collector portion 11 is When the pressure decreases, the valve body 26 moves to the right in FIG. 6 by the differential pressure to reduce the opening area of the orifice 27, and when the pressure in the intake collector portion 11 increases, the valve body 26 moves to the left in FIG. It moves so as to increase the opening area of the orifice 27.

That is, in the blow-by gas returning apparatus having the above-described configuration, under normal operating conditions except for a part of the high load region, the throttle valve 1 is passed through the scavenging passage 21 and the first blow-by gas passage 19.
6 Part of the intake air is introduced into the crankcase 5 from the upstream side, whereby the blowby gas in the crankcase 5 is discharged into the intake collector portion 11 through the second blowby gas passage 20 and the blowby gas recirculation passage 22. Will be done.

In Japanese Utility Model Laid-Open No. 61-152714, a scavenging passage for introducing fresh air from the upstream of the throttle valve 16 and a blow-by gas recirculation passage for returning blow-by gas from the inside of the cylinder head to the downstream side of the throttle valve 16 are provided. The blow-by gas returning device provided in both the cylinder group, that is, the first rocker cover 9 and the second rocker cover 10 is shown.

Further, in Japanese Utility Model Laid-Open No. 59-107012, one cylinder group, that is, the first rocker cover 9 is provided with a scavenging passage 21, and a blow-by gas recirculation passage 22 is connected to the second rocker cover 10 and the throttle valve 16. A configuration in which a second blow-by gas recirculation passage having a check valve is provided between the upstream side and the upstream side is shown. The check valve is configured to allow only the flow of blow-by gas from the inside of the second rocker cover 10 to the upstream side of the throttle valve 16 and is intended to discharge the blow-by gas under high load.

However, in the conventional blow-by gas reduction device configured as shown in FIG. 5, new intake air normally flows into only the first cylinder group 3 side, as described above. Blow-by gas in the crankcase 5 is the second on the second cylinder group 4 side.
Since it is discharged through the inside of the cylinder head 8, the blow-by gas concentration inside the second cylinder head 8 becomes very high. Since the second rocker cover 10 is cooled by the outside air, the blow-by gas condenses into highly acidic water, which mixes with the lubricating oil, resulting in the deterioration of the lubricating oil at an early stage. is there.

Further, in the configuration of Japanese Utility Model Laid-Open No. 61-152714, since the scavenging passage and the blow-by gas passage are provided for each cylinder head, the fresh air flowing in from the scavenging passage flows in a form of short-circuiting the inside of each cylinder head. , Will flow out to the blow-by gas passage of the same cylinder head. That is,
A large flow that ventilates the crankcase 5 is less likely to occur, and ventilation in the crankcase 5 tends to be insufficient.

In the configuration of Japanese Utility Model Laid-Open No. 59-107012, the second
Since fresh air is not introduced through the blow-by gas recirculation passage, it has the same disadvantages as the apparatus described in the above-mentioned US Pat. No. 3,661,128.

Means for Solving Problems A blow-by gas returning apparatus for an internal combustion engine according to the present invention is
In order to solve the above-mentioned problems, the inside of the cylinder head of the first cylinder group and the crankcase are respectively formed by the first blow-by gas passage, and the inside of the cylinder head of the second cylinder group and the crankcase are formed by the second blow-by gas passage, respectively. While communicating with each other, the throttle valve upstream side of the intake passage and the first
The inside of the cylinder head of the cylinder group is constantly communicated with the first scavenging passage, and the downstream side of the throttle valve of the intake passage and the inside of the cylinder head of the second cylinder group are communicated with the blow-by gas recirculation passage equipped with a blow-by gas control valve. In a blow-by gas reducing device for an internal combustion engine, the throttle valve in the cylinder head of the second cylinder group and the intake passage are arranged to allow fresh air to flow from the upstream side of the throttle valve into the cylinder head of the second cylinder group. A second scavenging passage is provided between the upstream side and the blow-by gas recirculation passage and the second scavenging passage are communicated with the cylinder head internal space of the second cylinder group through mutually independent spaces. It has a feature.

Action From the upstream side of the throttle valve in the intake passage to the second passage via the second scavenging passage
A part of the intake air is introduced into the cylinder head of the cylinder group. The intake air dilutes the blow-by gas concentration inside the cylinder head of the second cylinder group, and the acidity of water generated by condensation also weakens.

Embodiment FIG. 1 shows an embodiment of a blow-by gas returning apparatus for an internal combustion engine according to the present invention. Since the basic structure of this embodiment is the same as that of the conventional one described above, the same parts are designated by the same reference numerals, and a duplicate description will be omitted.

As described above, the crankcase 5 in which blowby gas collects communicates with the inside of the first cylinder head 7 via the first blowby gas passage 19, and inside the second cylinder head 8 via the second blowby gas passage 20. And the inside of the first cylinder head 7 is always communicated with the upstream side of the throttle valve 16 of the intake passage 14 through the first scavenging passage 21, and the inside of the second cylinder head 8 is connected to the blow-by gas recirculation passage 22 and It communicates with the downstream side of the throttle valve 16 via a blow-by gas control valve 23. And
In this embodiment, from the middle of the first scavenging passage 21 to the second
The scavenging passage 31 is branched and its tip is connected to the upper surface of the second rocker cover 10 on the second cylinder group 4 side. That is, the inside of the second cylinder head 8 and the intake passage 1
The upstream side of the throttle valve 16 of No. 4 is in constant communication with the second scavenging passage 31. A baffle plate 32 for separating the lubricating oil is also provided for the opening of the second scavenging passage 31. That is, the blow-by gas recirculation passage 22 opens toward the space surrounded by the baffle plate 25, whereas the second scavenging passage 31 opens toward the space surrounded by the baffle plate 32. The spaces inside the second cylinder head 8 communicate with each other through spaces independent from each other.

Therefore, according to the above configuration, under the engine operating conditions excluding a part of the high load region, the throttle valve 16 upstream from the first scavenging passage 2
At the same time, a part of the intake air is introduced into the inside of the first cylinder head 7 via 1, and a part of the intake air is also introduced into the inside of the second cylinder head 8 via the second scavenging passage 31.
The blow-by gas is pushed by the air flowing in from the first cylinder head 7 side and discharged through the inside of the second cylinder head 8. As a result of the air being introduced through the second scavenging passage 31, the blow-by gas is greatly Will be diluted to. Therefore, the acidity of the water produced by condensation is weakened, and early deterioration of the lubricating oil is prevented.

The ratio of the amount of air introduced into the first cylinder head 7 to the amount of air introduced into the second cylinder head 8 is as shown in FIG. 2 or FIG. It is possible to easily adjust by narrowing either one of the passage areas at the branch portion of the two scavenging passage 31 (FIG. 2) or by interposing the orifice 33 in the passage (FIG. 3).

Further, as shown in FIG. 4, the second scavenging passage 31 may be directly connected to the intake passage 14 upstream of the throttle valve 16.

Effect of the Invention As is apparent from the above description, according to the blow-by gas reduction device for an internal combustion engine according to the present invention, a large flow of fresh air flowing from the cylinder head of the first cylinder group to the cylinder head of the second cylinder group. With this, the inside of the crankcase can be reliably ventilated, and a part of the intake air can be guided into the cylinder head of the second cylinder group from the upstream side of the throttle valve in the intake passage to suppress the blow-by gas concentration inside the cylinder head. The acidity of condensed water can be weakened. Therefore, it is possible to prevent early deterioration of the lubricating oil.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a blow-by gas returning apparatus for an internal combustion engine according to the present invention, and FIGS. 2 and 3 are sectional views showing only a main part showing a different embodiment of the present invention, respectively.
FIG. 5 is a sectional view showing a further different embodiment of the present invention, FIG. 5 is a sectional view showing the structure of a conventional blow-by gas reducing apparatus, and FIG. 6 is a sectional view of a blow-by gas control valve. DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine main body, 5 ... Crank case, 7 ... 1st cylinder head, 8 ... 2nd cylinder head, 16 ... Throttle valve, 1
9 ... 1st blow-by gas passage, 20 ... 2nd blow-by gas passage, 21 ... 1st scavenging passage, 22 ... blow-by gas recirculation passage, 23 ... blow-by gas control valve, 3
1 ... Second scavenging passage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Kiyotaka Nakamura 2 Takara-cho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (56) References: 60-73818 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A cylinder head of the first cylinder group communicates with the crankcase by a first blow-by gas passage, and a cylinder head interior of the second cylinder group communicates with the crankcase by a second blow-by gas passage. The throttle valve upstream side of the passage and the inside of the cylinder head of the first cylinder group are always communicated by the first scavenging passage,
Further, in a blow-by gas reducing device for an internal combustion engine in which the throttle valve downstream side of the intake passage and the inside of the cylinder head of the second cylinder group are connected by a blow-by gas recirculation passage provided with a blow-by gas control valve, A second scavenging passage is provided between the inside of the cylinder head of the second cylinder group and the throttle valve upstream side of the intake passage so as to allow fresh air to flow into the cylinder head of the two cylinder group, and the blow-by gas is used. A blow-by gas reducing apparatus for an internal combustion engine, characterized in that the recirculation passage and the second scavenging passage are communicated with the internal space of the cylinder head of the second cylinder group through mutually independent spaces.