JPH0830416B2 - Engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intake system for a V-type engine having two cylinder rows arranged in a V-shape, and in particular, a surge tank is provided above each cylinder row. In addition, the present invention relates to an intake device in which an upstream end of an intake pipe extending from a cylinder row on the other side is opened in the surge tank, and an intersecting portion of the intake pipe is connected to each other by a connecting pipe.

[Conventional technology]

Conventionally, in multi-cylinder engines, blowby gas and EG
In order to distribute R, or additional fuel for starting to each intake pipe,
There is known a technique of communicating with each other by a distribution pipe arranged so as to traverse each intake pipe (for example, Jikkou Sho-46-
21123 publication).

On the other hand, in a V-type engine, a structure in which an intake pipe extending from a cylinder row on the opposite side is connected to a surge tank in an intake passage provided above each cylinder row is well known (US Pat. No. 4,577,596).

[Problems to be Solved by the Invention]

Most of the intake pipes having such a structure are integrally formed by casting, but since the cross-sectional shape of the intake pipe is generally a substantially circular shape, a substantially triangular groove is formed between adjacent intake pipes. Water may accumulate during cleaning and other operations.

Further, when the distribution pipe is arranged between the intake pipe and the V bank of the engine so as to traverse each intake pipe, there is a problem that the distribution pipe narrows the space inside the V bank.

[Means for solving the problem]

In order to solve the above problems, it is an object of the present invention to facilitate the removal of washing water falling on the upper surface of the intake pipe and to secure a large space inside the V bank even if a distribution pipe is arranged. And

In the intake system for an engine according to the present invention, a surge tank is provided above each of two V-shaped cylinder rows, and the intake pipe of each cylinder row is arranged from the inner surface of the V bank to above the other cylinder row. By extending diagonally upward toward the surge tank, the two cylinder rows intersect each other at the middle, and all the intake pipes are arranged in one row in the crankshaft direction at the same height. With
A connecting pipe extending in a direction traversing the intake pipe row is integrally provided below the intersection, and the connecting pipe is communicated with all the intake pipes.

[Action]

Even if the wash water may fall on the intake pipe, the flow of the wash water is not blocked by the connecting pipe, and the wash water is relatively high near the surge tank and relatively low near the intake port. It does not flow to the position or fall to both sides and stay on the intake pipe.

Further, the connecting pipe that is bridged over the lower side of the intake pipe row can be supported by the intake pipe without using any attachment member such as a stay, and can be provided in close contact with the intake pipe.

〔Example〕

Hereinafter, the present invention will be described with reference to the illustrated embodiments.
In the figure, reference numeral 1 is a V-type 6-cylinder engine, and two cylinder rows each having three cylinders on the upper surface of a cylinder block 2.
R and L are provided. A combustion chamber 5 including a cylinder head 3 and a piston 4 is formed in each of the cylinder rows R and L,
The combustion chamber 5 constitutes a cylinder. 6 is a crankshaft and 7 is a connecting rod.

Intake chamber 12 and exhaust valve 14 are provided in combustion chamber 5 via intake valve 11.
The exhaust passage 15 is connected via. The intake passage 12 has a port 16 formed in the V-bank formed in the cylinder head 3 and a manifold connected to the cylinder head 3.
It is formed in series so as to communicate with the atmosphere through 17.

The manifold 17 is provided with surge tanks 18 and 18 arranged above each cylinder head 3 and at a position substantially directly above an inlet side opening inside the V bank of the port 16.
It has a branch pipe (intake pipe) 19 extending from the other cylinder row to this surge tank 18, and the upstream side of each surge tank 18 is assembled into one by a collecting pipe (not shown), and then an air flow meter is installed. It is open to the atmosphere through. The above configuration is not much different from that of the conventionally known V-type multi-cylinder engine. It should be noted that the intake pipes 19 are set as two sets that intersect each other, and a space 19a for drainage is provided between them.

In the present invention, the intake passage 12 of the manifold 17 is cast from an aluminum alloy, and is obliquely upward from the ports 16 of the two cylinder rows R and L toward the surge tanks 18 arranged above the other cylinder row. The extending intake pipes 19 intersect with each other near the middle of both cylinder rows R and L. As shown in FIG. 1, this intersecting portion is configured such that all the intake pipes 19 are arranged in a line at the same height in the crankshaft direction.

Reference numeral 21 is a connecting pipe arranged below the intersection. The connecting pipe 21 is integrally formed below the intersecting portion of each intake pipe 19 so as to extend in a direction crossing the intake pipe row. And this connecting pipe 21 is used for all intake pipes 19
Is communicated to.

Although not shown in this embodiment, the connecting pipe 21 may be connected with a fuel amount increasing nozzle for cold start, or a recirculation passage for recirculating exhaust gas or blow-by gas to the intake passage.

According to this embodiment, even if the washing water falls on the manifold 17, the connection pipe 21 does not block the flow of the washing water, and the washing water flows from the relatively high position near the surge tank 18 to the port 16 It does not flow to a relatively low position in the vicinity or fall on both sides and stay on the manifold 17.

Further, since the surge tank 18 is positioned substantially directly above the inlet side opening of the port 16, since the surge tank 18 is separated upward from the cylinder heads 3 of the cylinder rows R and L,
In the meantime, the lower portion of the exhaust pipe 19 can be exposed over a wide area. Therefore, workability when cleaning the surge tank 18, the exhaust pipe 19, the cylinder head 3, and the like can be improved. By adopting this configuration, the upper wall portion of the intake device formed by the intake pipe rows between the surge tanks 18 is formed so narrow as to be located in the V bank when seen in a plan view. It becomes difficult for water to collect in the area.

〔The invention's effect〕

As described above, in the intake system for an engine according to the present invention, surge tanks are provided above two cylinder rows arranged in a V shape, and the intake pipe of each cylinder row is connected from the inner surface of the V bank to the other cylinder. By extending obliquely upward toward the surge tank arranged above the row,
The cylinders are intersected in the middle, and all the intake pipes are arranged in a line at the same height in the crankshaft direction, and the intake pipes are traversed below the intersections. Since a connecting pipe extending in the direction is integrally provided and this connecting pipe is connected to all intake pipes, there is no obstacle on the upper surface of the intake pipe, and the wash water that descends on the upper surface of the engine flows smoothly. There is an effect that it does not stay.

In addition, since the connecting pipe that is bridged over the lower side of the intake pipe row can be supported by the intake pipe without using any mounting member such as a stay, it can be provided in close contact with the intake pipe. It is possible to form a wide space surrounded by the intake pipe array and the V bank.

When a large space is obtained inside the V bank in this way, when arranging the fuel injection device here, for example, the degree of freedom in designing the mounting position of the fuel injection device becomes high and the work space becomes large. Workability is improved when performing attachment / detachment work and maintenance work of the fuel injection device.

Furthermore, if the above-mentioned configuration is adopted, the distance between the connecting pipe and the intake passage in the intake pipe becomes substantially equal in all intake pipes, and the resistance of the passage from the connecting pipe to the intake pipe becomes substantially equal in all intake pipes. , The fluid sent to the connecting pipe (blow-by gas, EGR, or additional fuel for starting) can be distributed to all the intake pipes almost evenly.

In addition, since all the intake pipes are arranged in a line at the same height in the crankshaft direction at the intersections of the intake pipes,
The connecting pipe provided on the lower side of this intersection does not have a step in the vertical direction in the middle. Therefore, the structure of the connecting pipe is simplified, and the fluid can smoothly flow in the connecting pipe.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a sectional view of an engine body, FIG. 2 is a sectional view taken along the line II-II, FIG. 3 is a sectional view taken along the line III-III, and FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 1. 12 ... Intake passage, 15 ... Exhaust passage, 16 ... Port, 17 ... Manifold, 18 ... Surge tank, 19 ... Branch pipe (intake pipe), 21 ...
Connecting pipe.

Claims (4)

[Claims] 1. A surge tank is provided above two cylinder rows arranged in a V shape, and an intake pipe of each cylinder row is arranged from the inner surface of a V bank to the surge tank arranged above the other cylinder row. By extending it diagonally upward, it intersects in the middle of both cylinder rows, and this intersection is configured so that all the intake pipes are lined up in a row at the same height in the crankshaft direction. An intake device for an engine, characterized in that a connecting pipe extending in a direction crossing the intake pipe row is integrally provided on the lower side of the intake pipe, and the connecting pipe is communicated with all the intake pipes. 2. The intake system for an engine according to claim 1, wherein the connecting pipe is provided with a fuel injection nozzle for increasing the starting amount. 3. The intake system for an engine according to claim 1, wherein a recirculation passage for blow-by gas is connected to the connecting pipe. 4. The intake system for an engine according to claim 1, wherein an exhaust gas recirculation passage is connected to the connecting pipe.