JPS61132719A - Duplex air intake unit of internal-combustion engine - Google Patents

Abstract

PURPOSE:To render the state of air intake optimum across the whole operation range of an engine. by providing an air intake passage for low loading which by passes a switching valve, in an engine provided with two air intake passages per cylinder to be switched depending upon the running condition of the engine. CONSTITUTION:Both an air intake passage 13 for low speed and an air intake passage 15 for high speed air prepared for one cylinder. Throttle valves 12, 14 are installed in respective passages and also opened or closed by means of a switching valve 18 depending upon the running condition of an engine. A bypass passage 16 is branched from the air intake passage 13 for intermediate loading, while bypassing the switching valve 18. A control circuit 28 fully opens a solenoid valve 23 according to the signals from throttle valve opening sensors 24, 25, a negative pressure sensor 26, and a rotational speed sensor 27 in the case of low loading and fully closes the switching valve by means of an actuator 20 so as to form a strong swirl by aid of high speed air intake action from the bypass passage 16. In the case of intermediate loading sufficient quantity of intake air and the swirl are maintained by opening the passage 13 and in the case of high loading, the passage 15 is also opened so as to secure a required quantity of intake air.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a dual intake system having a plurality of intake systems in an internal combustion engine, and particularly to one that divides the intake system under low and medium load operating conditions.

Blue version 1 of the invention This type of intake device includes a plurality of intake systems gathered immediately upstream of one intake valve, or a two-intake single type in which each intake system is provided with an intake valve. There is something. In order to improve combustion efficiency at low loads, one intake system generates a strong swirl when air is taken into the cylinder, and in order to reduce intake resistance at high loads, it is basic to draw air through the other thick intake system. It has become. Problem 1 to be Solved by the Invention Therefore, conventionally, regarding the above-mentioned dual intake system, for example, Japanese Patent Application Laid-Open No. 54-151721, Japanese Patent Application Laid-Open No. 53-1279
As shown in Japanese Patent No. 1γ, a sub-intake passage is provided for one main intake passage, and air is uniformly taken in through the sub-intake passage during low load. Therefore, although it is possible to achieve the desired purpose at low and high loads, the intake air is ambiguous at intermediate loads, and the performance of the combustion and output cap cannot be fully demonstrated at these intermediate loads. There is a problem. [Means for Solving the Problems 1] In view of the above-mentioned problems in the prior art J3, the present invention has the same performance as the conventional technology at low and high loads, and furthermore, An object of the present invention is to provide a dual intake system for an internal combustion engine that improves combustion and output. The means includes a primary side intake passage for low and medium loads, a secondary side intake passage for high loads, and a bypass passage that branches from the primary side intake passage and creates a swirl in the cylinder. An on-off valve is installed in both intake passages downstream of the branch point, and when the load is low, the on-off valve shuts off both intake passages.
It is characterized in that only the primary side intake passage is communicated during medium loads, and both intake passages are communicated during high loads. [Function] Based on the above configuration, when the load is low, air is taken in only from the bypass passage, creating a strong swirl inside the cylinder, and when the load is low or medium speed, air is taken through the bypass passage and the primary side intake passage, and the air is taken in appropriately. In addition to the generation of a swirl, an intake inertia effect is obtained, and when the load is high, the intake air is mainly carried out through both intake passages with little resistance. [Embodiment] An embodiment of the present invention will be described below based on the drawings. In Fig. 1, the case where the present invention is applied to one intake valve type is explained. Reference numeral 1 is a crankcase, 2 is a cylinder, 3 is a piston, 4 is a cylinder head, 5 is a combustion chamber, and 6 is an intake boat. , 7 is an intake valve, and a dual carburetor 8 is connected to the intake boat G via an intake pipe 9. Suction pipe 9 is 1 minute! The suction boat 6 is also divided into two parts by a partition wall 11 up to just upstream of the suction valve 7.
The primary side intake passage 13 is connected after the downstream throttle valve 12, and the secondary side intake passage rB1 is connected after the secondary throttle valve 14.
5 is formed. Also, a bypass passage 16 branches from the intake passage 13, and a narrow boat 17 of this bypass passage 16
is opened in the tangential direction of the cylinder immediately upstream of the intake valve of the intake boat 6. And between both intake passages 13.15 on the downstream side of the branching point of the bypass passage 1G, there is an rA opening valve 18.
This movement opens and closes both intake passages 13, 15, and only one of the intake passages 13 is opened. A diaphragm actuator 20 is attached to the on-off valve 18 via a rod 19, and this actuator 2
0 negative pressure chamber 21 communicates with a venturi negative pressure take-out boat 29 of the carburetor 8 through a passage 22, and a leak solenoid valve 23 is provided in the middle of the passage 22. Throttle valve 12
．． 14 has its opening sensor 24,25 connected to the intake passage 13.
A negative pressure sensor 26 is attached to each of these sensors 2.
4 to 26 and the signals of the rotation sensor 27 are input to the control circuit 28, and the output signal of the control circuit 28 is used to control the solenoid valve 2.
3 to open and close. Here, control circuit 2
8, the solenoid valve 23 is fully opened in a low-speed, low-load region including idle, depending on the relationship between the engine speed and the load, and the opening degree of the solenoid valve 23 is set to an intermediate value in a low-speed, medium-speed, medium-load region B. Solenoid valve 2 in high-speed, high-load region C
Fully open 3. Next, the operation of the device configured in this way will be explained. First, under low load operating conditions including idle, the solenoid valve 23 is fully opened by the output signal of the control circuit 28, so the venturi negative pressure of the boat 29 is leaked to the atmosphere, and the actuator 20 switches the on-off valve 18 between the primary and secondary valves. Both intake passages 13 and 15 on the next side are closed. Therefore, the air-fuel mixture produced by the primary throttle valve 12 of the carburetor 8 is supplied to the cylinder 2 through only the bypass passage 16, producing a strong swirl. Then, for medium loads, solenoid valve 23
Due to the intermediate opening degree, an intermediate venturi negative pressure acts on the negative pressure v21 of the actuator 20, so that the on-off valve 18 moves approximately half a stroke to open the primary side intake passage 13. Therefore, air is taken in through both the bypass passage 16 and the intake passage 13, creating a suitable swirl and being efficiently taken in due to the intake inertia. At a further high load, the solenoid valve 23 is fully opened and a large venturi negative pressure acts on the negative pressure chamber 21 of the actuator 2°. Therefore, the on-off valve 18 moves full stroke so that it also listens to the secondary side intake passage 15, and as a result, the mixture i) from the primary side J3 and the secondary side of the carburetor 8 is transferred to the passage 1.
3.15.16 and is supplied in a state with little intake resistance. An embodiment of the present invention has been described above.
The valve 18 may be of a rotary type, and various opening/closing mechanisms can be considered. It is also possible to apply the present invention to a two-intake valve type. Effects of the Invention 1 As is clear from the above explanation, according to the present invention, a strong swirl improves the combustion state at low loads, which is advantageous in terms of fuel efficiency, and at high loads, the output increases due to the reduction in intake resistance. will improve. Furthermore, at low to medium speeds and medium loads, air is taken in separately from the above, and appropriate swirl and intake inertia effects are obtained, improving combustion and output. Additionally, fluctuations in combustion are reduced, the lean limit and EGR limit are expanded, and drivability is improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the apparatus according to the present invention, and FIG. 2 is a diagram showing each area. 2... Cylinder, 6... Suction port, 8... Carburetor, 9... Suction pipe, 13... Primary side intake passage, 15
...Secondary side intake passage, 1G...Bypass passage, 18
...Opening/closing valve, 20...actuator.

Claims (1)

[Claims] It has a primary side intake passage for low and medium loads, a secondary side intake passage for high loads, and a bypass passage that branches from the primary side intake passage and creates a swirl inside the cylinder, and from the branch point of the bypass passage. An on-off valve is installed in both intake passages on the downstream side, and both intake passages are shut off by the on-off valve at low loads, only the primary intake passage is communicated at medium loads, and both intake passages are communicated at high loads. Dual intake system for internal combustion engines.