JPS58192921A - Intake device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the engine from the back-flow, during the operation in the range of low and medium speed and high load, as the result of attaching importance to the high speed performance of the titled engine by a method wherein an intake passage is divided into two parts and a check valve is provided in the one side passage. CONSTITUTION:During the high speed operation, the passage in a piston valve 18 of a carburetor 8 becomes high negative pressure, also the air chamber 22 of an actuator 19 becomes high negative pressure. The air chamber 16 connected with said actuator 19 with a pipe 23 becomes high negative pressure. Thereby, a throttle valve 11 is opened, the large quantity of mixed gas is fed into a combustion chamber 3. During the low or medium speed operation, said throttle valve 11 is kept on closing, accordingly, the small quantity of mixed gas is fed into said combustion chamber 3 via a reed valve 10.

Description

[Detailed description of the invention] The present invention relates to an air intake device that opens inward.

In engines that place emphasis on high-speed performance, the length of the intake pipe is shortened in order to increase the output at high speed. However, this causes a blowback phenomenon in the engine's normal speed range, and there is a problem that sufficient output cannot be produced.

In view of the above-mentioned problems, it is an object of the present invention to prevent barking in the low-medium-speed high-load range of an engine that emphasizes high-speed performance, and to prevent a decrease in output from occurring. The goal is to donate the open @Hiroshi equipment.

According to the present invention, which is distantly related to the above object, f! @ of A11M Seki
In a 4-stroke engine, Souseki divides the engine passage into two parts, one passage is equipped with a check valve that opens only for ventilation in the intake direction, and the other passage is equipped with a check valve that opens only for ventilation in the intake direction. A pressure-responsive throttle valve is provided, and this throttle valve is set to open when the carburetor pressure is applied when the engine is running at high speed, and to close when the carburetor has low negative pressure when the engine is running at low speeds. This is a characteristic feature.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below with reference to embodiments shown in the drawings.

In the figure, E is a four-stroke engine whose valve timing is set for high-speed performance. 1 is a cylinder that powers this engine E, and 2 is a piston. The combustion chamber 3 of the engine E is provided with an intake valve 4 corresponding to the intake passage 6 and an exhaust valve 5 corresponding to the exhaust passage 7. 8 is a carburetor, and 9 is a throttle valve.

The intake passage 6 is divided into two at a position far from the intake valve 4, and one passage 6a is provided with a reed valve 10, and the other passage 6b is provided with a throttle valve 11. Of these, the reed valve 10 is a check valve that allows flow in the intake direction but closes against flow in the opposite direction. Moreover, the passage 5a provided with this reed valve 10 is t! The arrangement is inclined so that air is introduced approximately tangentially to the A baking chamber 3.

The throttle valve 11 has an arm 12 fixed to the end of its shaft 11a, and a rod 1 of an actuator 13 is attached to the arm 12.
4 is pivoted. The actuator 13 includes an air chamber 16 formed by a diaphragm 15 and a spring 17 that elastically pushes down the diaphragm 15.

The piston valve of the carburetor 8 described above is operated by an actuator 19, and this actuator 19 has the same authority as the upper actuator 13, a diaphragm 20 and a spring 21 that pushes the diaphragm 20 downward. It consists of The air chamber 22 of the actuator 19 is communicated with the air chamber 16 of the actuator 13 through a pipe 23.

According to the engine configured as described above, when the engine E rotates at lji speed with the throttle valve 9 fully open, high negative pressure is generated in the piston valve passage of the carburetor 8, so that the air chamber of the actuator 19 22 is also subjected to high negative pressure, the diaphragm 20 moves upward against the elastic force of the spring 21, and the piston valve 18 is pulled up. l1iil? Since the air chamber 16 of the actuator 13 connected to if by the vibrator 23 also has a high negative pressure, its diaphragm 15 moves upward against the elastic force of the spring 17 and pulls up the rod 14. Therefore, the shaft 11a rotates via the arm 12, and the throttle valve 11 opens. However, at this high speed rotation,
The displaced air-fuel mixture is introduced into the combustion chamber 3 through the opened throttle valve 11.

On the other hand, if you tighten the throttle valve 9 at low and medium speeds,
Since the negative pressure generated in the carburetor 8 is small, the negative pressure applied to the air chamber 15 of the actuator 13 is not strong enough to pull up the diaphragm 15 and the rod 14 against the spring 17. Therefore, in this down position, the throttle valve 11
has a closed neck, and a relatively small amount of air-fuel mixture in the dish is sucked into the combustion chamber 3 side via the reed valve 10. At this time, even if the engine roars back, the throttle valve 11 is closed and the reed valve 10 is a check valve, so the roar will not flow back any further. The above-mentioned state is the same when the engine is in a low, medium speed, high load range, and the throttle valve 11 is closed, thereby preventing blowback from reed valve 1.

In addition, when the passage 6a is arranged at an angle so as to be substantially tangential to the combustion chamber 3, as in the actual example, the @ air actively generates a swirl in the combustion chamber 3, promoting complete combustion. to make on-site improvement even more effective.

Therefore, in the above-mentioned engine, even if the output is set for high-speed performance, the output will not be insufficient due to blowback from the engine at low and medium speeds.

As mentioned above, the intake system for an internal combustion engine according to the present invention includes:
In a 4-cycle engine, the engine's intake passage is divided into two, with one passage provided with a check valve that opens only for ventilation in the intake direction, and the other passage provided with a throttle valve that responds to the negative pressure of the carburetor. The throttle valve is set to open when the carburetor has high negative pressure when the engine rotates at high speeds, and close when the carburetor has low negative pressure when the engine rotates at low speeds, so high-speed performance is emphasized. Even if the engine is set to the above, it is possible to prevent blowback at low and medium speeds, thereby preventing a lack of output.

[Brief explanation of drawings]

FIG. 131 is a partially sectional side view of the apparatus according to the embodiment of the present invention, and FIG. 2 is a partially sectional side view of FIG. E...engine, 3...smoking chamber, 4...intake valve, 6.6a, 6b...intake passage, 8...carburizer, 10...
・Reed valve (check valve), 11...throttle valve, 12...arm, 13.19...actuator, 14...mouth/end, 23...pipe. Agent: Patent Attorney Makoto Ogawa − Patent Attorney: Ken Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] In a 4-cycle engine, the engine's intake passage is divided into two, with one passage provided with a check valve that opens only for ventilation in the intake direction, and the other passage provided with a throttle valve that responds to the negative pressure of the carburetor. The throttle valve is set to be opened by high negative pressure of the carburetor when the engine rotates at high speed, and closed by low negative pressure of the carburetor when the engine rotates at low speed. Device.