JPS58183818A - Suction device of engine - Google Patents

Abstract

PURPOSE:To produce a swirling effectively, by employing an arragement wherein a suction port for a reduced load has its center offset outwardly away from a cylinder row direction so as to locate it in the direction of stream having stronger suction forces. CONSTITUTION:Four cylinders are respectively provided with a lower suction port 6 for a reduced load and an upper suction port 7 for an increased load, these ports 6 and 7 being adapted to open and close by a single suction valve 8 and communicate with a carburetor 11 via a banana type inlet manifold 12. In this manner, a suction air stream takes place outwardly away from a cylinder row direction and at the same time an arangement is employed such that a suction port 6 for a reduced load has its center offset outwardly in an inclined relationship away from a cylinder row direction relative to a center of combustion chamber 3 so as to locate the suction port 6 in the direction of stream having stronger suction forces. This arrangement can provide many advantages such as that an intense swirling may be effectively produced with a result in improved combustion characteristics and fuel consumption property. In addition, an intensity of swirlings may be made uniform among cylinders, eliminating a possibility of the torque to be fluctuated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention effectively generates swirl within the combustion chamber to improve combustibility, and also makes the strength of the swirl in each cylinder approximately the same to prevent torque fluctuations. The present invention relates to an intake system for an engine.

Conventionally, engine intake systems have been equipped with a low-load intake boat and a high-load intake boat for each cylinder, a single intake valve that opens and closes both intake boats, and a high-load intake boat with a high-load intake boat. A device equipped with an on-off valve that opens when a load is applied has been proposed (Utility Model Publication No. 1983-61118).

The intake system of this engine closes the high-load intake boat with an on-off valve when the load is low, allowing intake air to be drawn into the combustion chamber only from the low-load intake boat, increasing the intake flow rate and strengthening the swirl. , which promotes fuel atomization and improves combustion performance and fuel efficiency.At the same time, when the load is high, the on-off valve is opened to draw in air from the high-load intake boat in addition to the low-load intake boat, improving charging efficiency. This has the advantage of improving output performance.

However, the conventional engine intake system described above does not have the ability to effectively generate swirl due to the relationship between the inlet manifold and the low-load intake port, and to make the swirl strength of each cylinder the same. This is because they do not take this into account and do not correlate the bias of the intake air flow in the intake passage determined by the type of inlet manifold (there are so-called banana type and tournament type) with the placement and direction of the low-load boat. As below,
Depending on the cylinder, the flow of intake air to the low-load intake boat becomes weak, making it impossible to strengthen the swirl, and there is also an imbalance in the strength of the swirl between the cylinders.

That is, the intake system of the conventional engine described above uses a tournament-type inlet manifold, and all low-load intake ports are offset in the same direction in the 7/7 row with respect to the center of the combustion chamber, and are arranged in substantially parallel directions. is oriented to open into the combustion chamber. However, in a tournament-type inlet manifold, in the intake path to the two outer cylinders, the intake air flows strongly toward the outside due to intake inertia, while in the intake passage to the inner two cylinders, the intake air flows due to intake inertia. The flow is strongly biased inward. However, as mentioned above, in the intake system of the conventional engine, each low-load intake port is offset in the same direction of the cylinder row with respect to the center of the combustion chamber, so the low-load port of one outer cylinder is Swirl can be strengthened by being offset outward in the direction of the cylinder row from the center of the combustion chamber, along the strong flow of intake air, but the low-load port of the other outer cylinder is offset outward in the direction of the cylinder row from the center of the combustion chamber. It is not possible to strengthen the swirl because it is offset inward and does not follow the strong flow of intake air.

Similarly, in both inner cylinders, one low-load intake port can strengthen the swirl along the strong flow of intake air, and the other low-load intake port is not along the strong flow of intake air, so Swirl cannot be strengthened.

Therefore, the conventional engine intake system described above cannot effectively generate swirl for all cylinders, and cannot sufficiently improve combustion performance and fuel efficiency.
This has the drawback that an imbalance occurs in the strength of the swirl between the cylinders, resulting in torque fluctuations.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks by relating the bias of the intake air flow in the intake passage determined by the type of inlet manifold to the arrangement and direction of the low-load boat. An object of the present invention is to provide a novel intake system for an engine that can effectively generate swirl in each cylinder and can make the strength of the swirl in each cylinder substantially the same.

Therefore, the structure and operation of the present invention is that each of the four cylinders is provided with a lower low-load intake port and an upper high-load intake port that are separated from each other by a partition wall, and both of the intake ports are opened and closed. In an engine in which a single intake valve is provided and each of the intake boats and the carburetor are communicated via an inlet manifold, the inlet manifold is formed into a banana shape to reduce flow loss due to bending of the passage. In addition to making the intake air flow smoothly, the flow of intake air in the intake passage is biased outward in the direction of the cylinder row, and at the same time, it is biased outward in the direction of the fern row in each low-load boat of two sets of cylinders that are divided at the center in the direction of the cylinder row. By offsetting, each low-load intake port is placed along the direction of the strong flow of intake air, effectively generating swirl, improving combustion performance and fuel efficiency, and reducing swirl in the combustion chamber of each cylinder. It is characterized in that the strength of the torque is kept approximately the same, so that torque fluctuation does not occur.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

Fig. 1 shows one cylinder A, where 1 is a cylinder arranged vertically, 2 is a cylinder head, 3 is a combustion chamber, 4 is an intake boat formed in the cylinder head 2, and 5 is the intake boat 4 arranged in a downward direction. A low-load intake port 6 is located above to supply the mixture to the combustion chamber 3 in a horizontal direction, and a high-load intake port is located above to supply the mixture to the combustion chamber 3 in a direction inclined with respect to the horizontal plane. 8 is a single intake Qll which opens and closes both the low-load intake port and high-load intake port 7 at the opening to the combustion chamber 3, and 8 is a carburetor;
12 is an inlet manifold that communicates the carburetor 11 with the low-load intake boat 6 and the high-load intake boat 7; 13 is rotatably supported on the inlet manifold 12 by a shaft 14; 7 is an on-off valve that opens and closes, and the on-off valve 13 is closed during low load,
Wei Aiki combustion chamber 3# only from intake boat 6 for low load? This increases the flow rate of the mixture, strengthens the whirl inside the combustion chamber 3, promotes fuel atomization, and improves fuel performance and fuel efficiency. It is supplied to the combustion chamber 3 from the low-load intake boat 6 and the high-load intake port 7 to improve intake efficiency and charging efficiency, and improve output performance.

In addition, 15 is an exhaust boat formed on the 7 cylinder head 2,
16 is an exhaust valve, 17 is a camshaft, 18° 18 is a rocker arm shaft, 19.19 is a rocker arm, 20.
20 is a pulp spring.

On the other hand, in FIG. 2, B, C, and D are cylinders having substantially the same structure as the above-mentioned cylinders.

The above four cylinders A, B, C, and D are each cylinder 1.1
．． 1.1 is arranged vertically, and the cylinders 1.1.1.1 are arranged in the same horizontal plane to form a linear/ring row. Each of the above cylinders A, B, C, D
An inlet manifold 12 for supplying air-fuel mixture to the engine is formed into a banana shape. Therefore, the bending of the intake passage 25 formed by the inlet manifold 12 and the intake boat 4 is less than when a tournament-type manifold is used, and the intake resistance due to the bending of the intake passage 25 is reduced. Along with this, the intake passage 25
Branch passages 25A, 25B, 25C,
The air-fuel mixture flowing to 25D is biased toward the outside in the cylinder row direction due to its inertia. In other words, arrows VA and VB in FIG.

As shown in V c and Vo, each branch passage 25A,
At 258 degrees 25C and 25D, the flow velocity is faster and the flow rate is larger in the outer portion in the cylinder row direction.

Low load intake boat for each cylinder A, e, c, D above 6.6
, 6.6 are divided into two groups with the center of the cylinder row as the boundary, and the center lines XA, xB of the low-load intake boats 6.6 in one group and the center lines XA, xB of the low-load intake boats 6.6 in the other group. It is symmetrically inclined outward in the cylinder row direction with respect to the center lines Xc and XD of No. 6. That is, as shown in Figure 2.3.4,
Inner wall v of each low-load intake boat 6 in the cylinder row direction
7jJ27, the center line X of each low-load intake boat 6
A.

X B, X (:, X D are inclined so as to be offset outward in the cylinder row direction with respect to the center of each combustion chamber 3.

In the engine intake system configured as described above, the engine is currently in a low load state, and each cylinder A and B is in a low load state.

It is assumed that the high-load intake ports 7 of C and D are closed by on-off valves 13.

At this time, from the carburetor 11 to the inlet manifold 12
Branch passage 25A, 25825 through the base 25F of
Since the inlet manifold is banana-shaped, the air-fuel mixture flows to C and 25D as shown by the arrow VA in FIG.

As shown in V, VC, and VD, the flow is biased toward the center of the cylinder row so that the outward flow in the direction of the cylinder row is stronger, and since the on-off valve 13 is closed, each cylinder A
, B, C, D low load intake bow) 6, 6, 6.
6 only, and the flow velocity is increased.

These low-load intake bows for each cylinder A, B, C, and D) 6, 6
, 6.6 are all inner wall surfaces 27.2 in the cylinder row direction.
7, 27. 27, its respective low load intake bow) 6, 6,
6.60 The center lines XA, The air has little resistance due to bending, and is smoothly guided horizontally into each combustion chamber 3, so that it flows into each cylinder A,
B, C, Di arrows SA, SB, S (:, SD
(strength as shown in FIG. 1) A horizontal swirl is effectively generated, and the swirl strength of each cylinder A, B, C, and D is approximately equal.

, Therefore, due to the effective generation of this swirl,
Combustion performance and fuel efficiency have been greatly improved, and each cylinder A,
By making the swirl strength uniform among B, C, and D, engine torque fluctuations are extremely reduced, and drivability is extremely improved.

Next, assume that the engine is operating under high load6,6
．． 6 and high load intake bow) 7, 7, 7.7 to the combustion chamber 3.3.3.3, improving charging efficiency and output performance.

As is clear from the above explanation, the engine of the present invention is provided with an upper high-load intake boat, and each of the intake boats and the carburetor are communicated with each other via a banana-shaped inlet manifold to control the flow of intake air into the cylinder. The low-load intake boats are arranged along the strong flow of intake air by slanting them so as to be offset outward in the direction of the cylinder row, so they can effectively generate a strong swirl, improving combustion performance and fuel efficiency. In addition to improving performance, the strength of the swirl in each cylinder can be made uniform.
It is possible to prevent torque fluctuation from occurring.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view of the above-mentioned embodiment, and FIGS. 3 and 4 are cross-sectional views of essential parts, respectively. 3... Combustion chamber, 5... Partition wall, 6... Intake boat for low load, 7... Intake boat for high load, 8... Intake valve, 11... Carburizer, 12... ...Banana-shaped inlet manifold, 13...Opening/closing valve, 27...Wall surface.

Claims (1)

[Claims] tl) Equipped with four cylinders, each cylinder is opened and closed by a single intake valve and divided by a partition wall, with a low-load intake boat located below and a high-load intake boat located above. In an engine, the upstream end of each intake boat is connected to an inlet manifold which communicates with a carburetor at one end. An intake system for an engine, characterized in that an inner wall surface in a cylinder row direction is inclined outward and in a direction offset from the center of a combustion chamber.