JPH04194316A - Suction device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent back flow of the sucked air to cause an increase in the torque even in a high-revolution region of the engine by dividing the portion of a suction passage between a throttle valve and a suction valve into two parts, an upstream-side portion and a downstream-side portion, by a suction control valve and a plurality of read valves. CONSTITUTION:An enlarged portion 2a of a suction pipe at one side thereof 2 is connected to a passageway leading to a suction valve of a cylinder, and the suction pipe at the other side thereof is provided with a throttle valve. The enlarged portion 2a is mounted thereto with a main body 1 in a manner that an opening portion 1a thereof is directed toward the throttle-valve side. The suction passage of the suction pipe 2 is divided, by a suction control valve 3 and four read valves 4 provided in parallel thereto, into two parts, an upstream-side portion communicated with the throttle valve and a downstream-side portion communicated with a suction valve. The four read valves 4 as a whole decreases the suction resistance at the time when the sucked air passes through these reed valves 4 to permit the sucked air to pass therethrough in large amount, thereby enabling suction to be done through operation of the reed valves 4 alone even when the number of engine revolutions is relatively large. In this way, back flow of the sucked air is prevented to cause an increase in the torque during such time period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake system for an internal combustion engine having a reed valve provided in an intake passage to prevent backflow of intake air.

[Conventional technology]

An intake system for an internal combustion engine is disclosed in Japanese Unexamined Patent Application Publication No. 1-1-1, which has an intake control valve in the intake passage of the engine in addition to a throttle valve, and in which the intake control valve is provided with a reed valve.
It is described in Japanese Patent No. 21510.

This closes the intake control valve when the engine is running at low speeds.
The reed valve installed in the intake control valve supplies intake air into the cylinder, prevents backflow of intake air, improves torque, increases rotational speed, and supplies intake air through the reed valve. When the amount of intake air becomes insufficient, the intake control valve is opened to supply the necessary amount of intake air into the cylinder, thereby preventing a decrease in torque due to insufficient intake air.

[Problem to be solved by the invention]

In the conventional intake device described above, the intake control valve provided in the intake passage has a flat plate shape so as not to create intake resistance in the fully open position.

The reed valve is a single, not very large reed valve, since it is provided on the intake control valve itself. Therefore, this reed valve inevitably creates a large intake resistance when passing intake air, and cannot pass a large amount of intake air, so it is used only when the engine is running at low speeds, and when the engine is running at higher speeds. , the intake control valve equipped with a reed valve is opened to supply the required amount of intake air into the cylinder.

As a result, the intake control valve opens when the engine speed increases slightly, increasing the amount of intake air into the cylinder, but it is not possible to prevent backflow of intake air, so in the mid-to-high rotation range, torque can be improved by preventing backflow. cannot be expected.

Therefore, an object of the present invention is to provide an intake system for an internal combustion engine that can improve torque by preventing intake air from blowing back even at relatively high rotational speeds.

[Means to solve the problem]

In order to achieve the above object, an intake system for an internal combustion engine according to the present invention includes an intake control valve and a plurality of intake control valves that are provided in parallel with the intake control valve and open downstream between the throttle valve and the intake valve in the intake passage. It is characterized by being divided into two parts, an upstream side and a downstream side, by a reed valve.

[For production]

With the above-mentioned structure, multiple reed valves reduce the intake resistance as a whole when passing intake air, and it is possible to pass a large amount of intake air, so even at relatively high rotation speeds, multiple reed valves Intake air can now be supplied into the cylinder via the reed valve, which prevents intake air from blowing back and improves torque.

At higher rotational speeds, the intake control valve is opened (-) to supply an amount of intake air into the cylinder according to the rotational speed, thereby preventing a decrease in torque due to insufficient intake air.

〔Example〕

In FIG. 1, reference numeral 1 indicates a rectangular prism-shaped main body, and reference numeral 2 indicates an intake pipe having an enlarged portion 2a at the end.

An intake control valve 3 is provided on one end surface of the main body 1, and an opening 1a is formed on the end surface facing the intake control valve 3. Further, openings 1b are formed in each of the four side surfaces of the main body 1, and a lead 4a is attached to the outside of each side with a stopper 4b and a cantilever on the opening la side so as to cover the openings 1b. Four reed valves 4 of the same size are formed in parallel with the intake control valve 3.

The enlarged portion 2a of the intake pipe 2 is connected to a passage to an intake valve (not shown) of the cylinder, and the other side of the intake pipe 2 is provided with a throttle valve (not shown). The main body 1 is attached to the enlarged part 2a of the intake pipe 2 with the opening 1fflla facing the throttle valve side, and the intake passage of the intake pipe 2 is
The intake control valve 3 and the four reed valves 4 provided in parallel thereto divide the valve into two parts: an upstream side that communicates with the throttle valve, and a downstream side that communicates with the intake valve.

The opening 1a of the main body 1 has a size equal to or larger than the cross section of the upstream passage of the intake pipe 2 so as not to create resistance when the intake air passes through, and the intake control valve 3 also has a similar size when it is fully open. It is formed to be.

The intake control valve 3 has a rotating shaft 3a at the center, and this rotating shaft 3a passes through the enlarged portion 2a of the intake pipe 2 and is directly connected to the rotating shaft of an intake control valve of the same shape in another intake pipe. A single drive (not shown) is mounted at the extreme end. This drive device drives all the rotating shafts 3a and opens and closes all the intake control valves at the same time. As this drive device, for example, one that opens the intake control valve 3 using negative pressure and closes it using the restoring force of a spring can be considered.

The intake system of the internal combustion engine of this embodiment has the intake control valve 3 and the four reed valves 4 provided in parallel with the intake control valve 3, as described above, and each of the four reed valves 4 has a Because it is formed to a size of Intake can be performed only by the valve 4, preventing backflow of the intake air and improving torque during that time. When the engine revs higher,
The intake control valves 3 of all intake pipes are opened by the drive device,
By supplying intake air into the cylinder in an amount corresponding to the rotational speed, it is possible to prevent a decrease in torque due to insufficient intake air.

As described above, the intake system of the internal combustion engine of this embodiment has the second
As shown in the figure, between the rotational speed N1 at which the conventional intake control valve is opened and the rotational speed N2 at which the intake control valve of this embodiment is opened, a higher torque is achieved compared to the conventional one due to the effect of preventing backflow of intake air. Obtainable.

〔Effect of the invention〕

As described above, according to the intake system for an internal combustion engine of the present invention, intake air can be supplied into the cylinder through the reed valve even at relatively high rotational speeds, so that backflow of intake air can be prevented even in the high rotational speed range. can improve torque,
The engine can be made to have higher torque and longer life compared to conventional engines.

Conventionally, the rotation axis of the intake control valve is provided at the end of the intake control valve because the reed valve opening is located in the center of the valve. In the present invention, the rotation axis of the intake control valve is
It can be provided in the center of the valve, and the torque required to open and close the intake control valve can be reduced compared to the conventional one, making it possible to downsize the drive device.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an intake system for an internal combustion engine according to the present invention, and FIG. 2 is a graph showing the relationship between torque and rotational speed. 1...Main body, 2...Intake pipe, 3...
Intake control valve, 4...Reed valve.

Claims (1)

[Claims] The space between the throttle valve and the intake valve in the intake passage is divided into two parts, an upstream side and a downstream side, by an intake control valve and a plurality of reed valves that are provided in parallel with the intake control valve and open downstream. Intake system for internal combustion engines.