JPH05125944A - Variable air-intake device of internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the outputs of an engine in the whole speed range from low to high speed using a variable air-intake system. CONSTITUTION:The branches 8 of an intake manifold 10 are formed by two pipes of large and small diameters and a fan-shaped valve 12 and a plate-shaped valve 13 are provided, respectively, at the entrance and exit branching points of the large diameter branch 8a and the small diameter branch 8b and a control circuit 18 is provided which controls the fanshaped value 12 and the plate-shaped value 13 by means of intake negative pressure, etc. The fan-shaped valve 12 and the plate-shaped valve 13 are opened and closed by the control circuit 18, and a passage for low speed is formed by use of the small diameter branch 8b alone, and a passage for medium speed is formed as a whole when the small diameter branch 8b is utilized as a resonator. Further, a passage for high speed is formed by opening only the large diameter branch 8a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable intake system for an internal combustion engine in a four-cycle engine for an automobile, which improves the output characteristics of the engine by changing the intake state of the engine intake system.

[0002]

2. Description of the Related Art Conventionally, in order to improve the output of an automobile engine, there is a system in which a resonator is attached to an intake system duct to reduce intake noise and resonance noise. Although various means are used to dispose the resonator in the engine room, as shown in FIG. 8, the surge tank 3 is provided along the curved space of the branch 2 of the intake manifold 1 by utilizing it. There is one provided with an open resonator (air chamber) 4. Since the volume of this resonator 4 is constant with respect to the number of revolutions of the engine, pulsation does not match in a certain speed range, and there is a possibility that the torque may be reduced. On the other hand, by mounting a resonator at another location, the pipe line of the resonator can be deformed depending on the engine speed (see Japanese Utility Model Publication No. 1-63769), and the diameter of the connecting pipe of the resonator can be changed (real system
59-2919 gazette), and those that improve the effect are manufactured.

In addition, there is a method in which the passage of the branch 2 is changed according to the engine speed to improve the engine output. In FIG. 9, the branch 2 of the intake manifold 1 is composed of two types, a short type branch 2a and a long type branch 2b, and a variable valve 5 attached to the short type branch 2a is used for low, medium and high speed ranges. The passages are opened and closed according to the operating conditions, and used properly to obtain the optimum characteristics. Particularly, in the intake manifold 1 of a four-valve engine, as shown in FIG. 10, a plate valve 6 similar to a throttle valve is provided at one of the branched branches 2 with an inlet valve (not shown).
The intake valve is installed immediately before to improve the intake flow velocity by operating one side of the inlet valve in the low speed range, and in the high speed range, the intake resistance is reduced by opening this plate-shaped valve 6, and optimal control is performed in each range. It is intended to improve the output.

[0004]

However, the branch 2 shown in FIG. 9 has two types of characteristics, a low-speed type characteristic and a high-speed type characteristic, and the valve 5 is switched at the intersection of the low-speed characteristic and the high-speed characteristic. That is, since it is performed in the vicinity of the same torque value (almost in the medium speed range), there is a problem that the torque in the substantial medium speed range is not improved. Further, in the structure shown in FIG. 10, since the plate-shaped valve 6 is provided at the branched one of the outlets of the branch 2, the intake resistance in the high speed range cannot be avoided. Therefore, it is difficult to improve the engine output over the entire area.

It is an object of the present invention to provide a variable intake system for an internal combustion engine for improving the output of an automobile engine from low speed to high speed.

[0006]

In order to achieve the above object, the present invention is connected to a cylinder head of an engine,
Each branch of the intake manifold is formed of two pipes of large diameter and small diameter, valves are arranged at branch points at both ends of the branch, and a control circuit for controlling both valves is provided. One of the branches is opened, or both are opened, and one of the large diameter branch and the small diameter branch is opened by a valve on the outlet side.

[0007]

Since the present invention is configured as described above, when the control circuit opens only the small-diameter branch with the valve on the inlet side and only the small-diameter branch with the valve on the outlet side, the low-speed passage is opened. Can be formed. Also, if both large and small diameter branches are opened by the valve on the inlet side and only the large diameter branch is opened by the valve on the outlet side, the small diameter branch is used as a resonator and the passage for medium speed as a whole. It is formed.
Further, when the control circuit opens only the large-diameter branch with the valve on the inlet side and opens only the large-diameter branch with the valve on the outlet side, a high-speed passage is formed.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the intake system of a four-cycle engine mounted on an automobile, as shown in FIG. 7, an intake manifold 10 in which the tips of the branches 8 extending from the surge tank 7 are juxtaposed by a plate 9 is used to suck the cylinder of the engine 11. Mounted on the side. In addition, as shown in FIGS. 1 and 2, the branch 8 is a short branch having a large inner diameter (large diameter branch).
8a is combined with a long branch having a small inner diameter (small diameter branch) 8b, a fan-shaped valve 12 is arranged at a branch point on the surge tank 7 side, and a plate-shaped valve is arranged at a branch point on the cylinder side.
13 are provided. Although the cross-sectional shape of these branches 8a and 8b is not particularly specified, it has a shape that can be opened and closed by the fan-shaped valve 12 shown in FIG.

The fan-shaped valve 12 and the plate-shaped valve 13 are rotatably attached via shafts 14 and 15, respectively, and a wire 17 is wound around a pulley 16 fixed to the shafts 14 and 15 to transmit drive. As shown in FIG. 6, the control for rotating the fan-shaped valve 12 and the plate-shaped valve 13 receives the speed sensor S1 and the pressure sensor S2 for detecting the engine speed and the negative pressure in the intake manifold, and the detection signals thereof. A computer CPU
Control circuit 18 consisting of motors M1 and M2 and actuators (pulley 16, wire 17, etc.) A1 and A2 that are operated according to the calculation result of
Is controlled by.

Next, the operation will be described with reference to FIGS. 4 and 5. First, when the engine is running at low speed, the large-diameter branch 8a is closed by the fan-shaped valve 12 and the plate-shaped valve 13 so that only the small-diameter branch 8b serves as a passage (left side in FIG. 4). As a result, the flow velocity of the air is increased, and the pulsation is adjusted to the low speed type to obtain the torque in the low speed region. The low speed characteristic becomes a broken line a shown in FIG.

At medium speed, the fan-shaped valve 12 is moved to an intermediate position (center of FIG. 4), and the plate-shaped valve 13 is used to branch the small diameter.
Close 8b, use two passages. The small-diameter branch 8b is used as a resonator for the resonance supercharging effect. The medium speed characteristic is indicated by the alternate long and short dash line b in FIG.

At high speed, the small-diameter branch 8b is closed by the fan-shaped valve 12 and the plate-shaped valve 13 (right side in FIG. 4), and only the large-diameter branch 8a is used. As a result, the shape up to the intake valve in the cylinder is made as straight as possible to directly inject air and reduce the intake resistance.
Further, since the tapered fan-shaped valve 12 is narrowed down little by little, the inertia supercharging can be utilized to the maximum and the output in the high speed range can be improved. The high speed characteristics are shown by the solid line c in FIG.

In this way, by detecting the engine rotation speed and the suction negative pressure and operating the fan-shaped valve 12 and the plate-shaped valve 13 by the computer CPU, an optimum passage is formed according to the situation, and the low speed and the medium speed are controlled. By connecting the best matching zone for high speed, the output can be improved over the entire area. Instead of the fan valve 12, a mechanism of a plate valve 13 may be attached and the plate valve 13 may be gradually rotated.

[0014]

Since the present invention is configured as described above, three types of branches are formed by properly using two branches for low speed, medium speed, and high speed, and each branch is adjusted to the optimum value. By controlling the fan-shaped valve and the plate-shaped valve, the output can be improved over the entire rotation speed of the engine. Therefore, it is possible to improve the comfort of riding and save fuel consumption.

[Brief description of drawings]

FIG. 1 is a sectional view of an intake manifold of an embodiment according to the present invention.

FIG. 2 is a perspective view of the intake manifold of the embodiment.

FIG. 3 is a perspective view of a fan-shaped valve in the intake manifold of the embodiment.

FIG. 4 is an explanatory diagram showing control of a fan-shaped valve and a plate-shaped valve of the embodiment.

FIG. 5 is a graph showing changes in engine output due to control of the fan-shaped valve and the plate-shaped valve of the embodiment.

FIG. 6 is a control block diagram of the fan-shaped valve and the plate-shaped valve of the embodiment.

FIG. 7 is a perspective view of an engine and an intake manifold of the embodiment.

FIG. 8 is a sectional view of a conventional intake manifold.

FIG. 9 is a cross-sectional view of a conventional intake manifold.

FIG. 10 is a sectional view of a conventional intake manifold.

[Explanation of symbols]

 8 branches 8a large diameter branch 8b small diameter branch 10 intake manifold 11 engine 12 fan valve 13 plate valve 18 control circuit

Claims (1)

[Claims] 1. A control circuit for connecting each branch of an intake manifold, which is connected to a cylinder head of an engine, with two pipes having a large diameter and a small diameter, arranging valves at branch points at both ends of the branch, and controlling the both valves. Is provided, one of the large diameter branch and the small diameter branch is opened by the inlet side valve, or both are opened, and one of the large diameter branch and the small diameter branch is opened by the outlet side valve. A variable intake system for an internal combustion engine.