JPS6050968B2 - intake manifold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake manifold for an engine, and its purpose is to change the effective length of the intake manifold between high-speed and low-speed engine rotation to obtain an optimal inertial supercharging effect. It is.

In order to obtain the effect of inertial supercharging of the engine, it is desirable that the length of the intake manifold in each rotation range be an equivalent pipe length that matches the air column vibration of air compression waves generated inside the intake manifold.

However, as it is well known, the length of conventional intake manifolds is a fixed, preset length, so the air column vibration frequency generated in the incoming air differs between low speed rotation and high speed rotation. Therefore, proper inertial supercharging cannot be obtained at all times, and a phase difference occurs between the opening and closing of the intake valve and the vibration of compression waves in the incoming air, resulting in insufficient air inflow, or when a part of the inflated air There was a problem in that the part flowed backwards again and the optimal inertial supercharging effect could not be obtained. In view of the above-mentioned conventional problems, the present invention adopts a double manifold configuration, and uses a switching valve to change the actual length of the intake manifold between low-speed rotation and high-speed rotation, thereby ensuring the equivalent pipe length in each rotation range. It is characterized by the fact that it can be obtained. Embodiments of the present invention will be described below with reference to the drawings.

1 is an engine, 2 is an intake manifold, and 3 is an air introduction part.

4, 5, and 6 are branch manifolds that connect to each cylinder. In the example shown, half of the cylinders of a 6-cylinder engine are shown in cross section, and the internal structure of the other half that is not shown in cross section is exactly the same. It is configured.

The present invention provides a vacant space 7 with a required volume at the back of the branch manifolds 4, 5, and 6 by means of a partition wall 12, and the partition wall 12 includes the branch manifold 6 closest to the central air introduction section 3.
Openings 10 and 11 are provided at positions corresponding to the other branch manifolds 4 and 5 except for the openings 10 and 11.

Furthermore, a communication portion 8 is provided on the side of the empty chamber 7 that is closer to the air introduction portion 3.
is opened and an on-off valve 9 is provided in this part. Next, the operation of the present invention will be explained.

When the engine 1 rotates at low speed, the on-off valve 9 is closed.
However, it remains open during high-speed rotation. The opening/closing of the on-off valve 9 is controlled by detecting the rotational speed of the engine 1 and using an actuating device electrically, hydraulically, pneumatically, or the like. Therefore, during low-speed rotation with the on-off valve 9 closed, the gate opens in the empty chamber 7.
is substantially a wall, and the lengths of the tubes of each branch manifold 4, 5, 6 are conventionally A-B) A-CNA-D.

Also, during high-speed rotation with the on-off valve 9 open, the empty chamber 7
is the same as the atmospheric pressure and acts as a surge tank, so the actual pipe length of each branch manifold 4, 5, 6 is B''-B.
It is shortened to C″-ClD″-D. Therefore, according to the present invention, the pipe length of the manifold changes between low-speed rotation and high-speed rotation, and the equivalent pipe length is always ensured, so that the frequency of air column vibration, that is, the pressure fluctuation, generated within the manifold is reduced. There is no drastic change due to low or high engine speeds, and the opening and closing of the intake valve follows the engine speed, making effective use of the air column vibration of the incoming air, increasing volumetric efficiency, and increasing the volumetric efficiency within the cylinder. has the advantage of significantly improving the effectiveness of inertial supercharging, which is filled with the densest air.

[Brief explanation of drawings]

The drawing is a sectional view of essential parts of the intake manifold according to the present invention. 1...engine, 2...intake manifold, 3...
Air introduction part, 4, 5, 6... Branch manifold, 7...
・Vacancy, 8...Communication, 9...Opening/closing valve, 10,1
1...Opening, 12...Partition wall.

Claims (1)

[Claims] 1. In the intake manifold of an engine, a branch manifold connected to each cylinder is provided with a vacant chamber with a required volume through a partition wall, and the partition wall is provided with an opening at a position corresponding to the branch manifold, and the vacant chamber is provided with an opening at a position corresponding to the branch manifold. An intake manifold, characterized in that the air intake manifold and the air introduction part are communicated with each other through a communication part, and an on-off valve is provided in the communication part.