JPS6125915A - Intake-air device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To ensure a satisfactory swirl effect over various operating ranges, by providing a control valve at the bifurcate point between primary and secondary intake-air ports, and by opening and closing this control valve in accordance with the operating condition of an engine to preferentially feed intake-air from the primary intake-port. CONSTITUTION:Upon idling operation the negative-pressure in an intake-air pipe is highest, and therefore, an actuator 11 closes a control valve 10, and a valve element 18 in the control valve 10 is inclined to slightly open a primary intake- air port 4 alone. Therefore, mixture from a carburettor 9 is deflected in the direction tangential to an engine cylinder by the valve element 4 and is, therefore, led to the outlet side of the primary intake-air port 4, so that the mixture is introduced into the cylinder at an increased flow rate in accordance with the opening degree of the valve element. Meanwhile, upon partial load operating the control valve 10 is rotated in its opening direction gradually in accordance with the decreasing negative pressure of intake-air. Therefore, the inclination of the valve element 18 is gradually decreased to increase the opening degree of the primary intake-air port 5 while the secondary intake-air port 5 is started to be opened, thereby it is possible to create swirl in accordance with loads.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an intake system for a two-intake valve type internal combustion engine, and in particular to a variable swirl mechanism that changes the generation of swirl during idling and partial operation without reducing full-open performance. .In internal combustion engines, without reducing performance at high loads,
2 with an intake valve to improve combustion efficiency at low loads.
A two-intake valve type has been proposed in which a primary intake port having another intake valve is added to the next intake port.

[Conventional technology]

The above-mentioned two-intake valve type internal combustion engine has the same intake operation as dual intake or split intake in which the intake valve is one and the primary and secondary intake ports are gathered just before the intake valve. There are prior art publications such as JP-A No. 54-97620 and JP-A No. 54-169610. The primary suction port for low loads is narrow and oriented tangentially to the cylinder, and is configured to generate swirl. Further, each intake port is separated by a partition wall within the intake manifold on the upstream side, and the intake air amount on the secondary side is controlled mainly by an on-off valve in the intake passage on the secondary side according to operating conditions. Therefore, it is necessary to set the diameter and direction of the primary side suction port to a predetermined value, and specifications must be made separately for each engine when the swirl generation conditions are different. In addition, since the amount of intake air is fixed as well as the opening of the primary intake port, if air starts to be taken in from the secondary intake port during partial operation, there are problems such as extremely low swirl effects.

[Purpose of the invention]

In view of the above-mentioned problems in the prior art, the present invention generates a variable swirl according to the intake air amount not only during low load including idle link but also throughout the partial state, and has a special structure of the primary intake port. It is an object of the present invention to provide an intake device for an internal combustion engine that does not require the use of an internal combustion engine and can easily create various swirl generating conditions.

[Structure of the invention]

For this purpose, the configuration of the present invention is such that the primary and secondary intake ports each have their own intake valves are bifurcated into a bifurcated configuration.
A single control valve is provided between both suction ports at the bifurcation point,
The gist of the system is to open a control valve according to engine operating conditions, and at this time, the control valve preferentially takes in air from the primary intake port and deflects it in the tangential direction of the cylinder.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described based on the drawings. In Fig. 1, to explain the intake system of one cylinder of an internal combustion engine, reference numeral 1 is a cylinder head, 2 is a combustion chamber formed therein, and the cylinder head 1 is connected to a common intake port 3 with approximately the same diameter. The primary side suction port 4 and the secondary side suction port 5 are bifurcated by a partition wall 19 to communicate with the combustion chamber 2, and each suction port 4.5 is provided with an intake valve 6.7. It will be done. The common suction port 3 is configured to communicate with a carburetor 9 via an intake manifold 8, and a control valve 10 is provided between both suction ports 4 and 5 at a branch point A of both suction ports 4.5. A diaphragm actuator 11 opens and closes the control valve 10 according to operating conditions. The actuator 11 has a negative pressure chamber 1 having a spring 12.
3 is communicated with the intake manifold 8 via the passage 14,
A diaphragm 15 is connected to a valve shaft 11 of a control valve 10 via a link 16, and a spring 12 opens the control valve 10 as the load increases and the negative pressure in the suction pipe decreases. Here, during idling, the valve body 18 of the control valve 10 closes the secondary suction port 5 and slightly opens the primary suction port 4, and is tilted in the tangential direction of the cylinder. The opening degree of both suction ports 4.5 is increased, and when the throttle is fully opened, both suction ports 5 and 4.5 are fully opened in line with the partition wall 19. Next, the operation of the intake device having the above structure is shown in FIG.
) or 0). First, during idle link, since the suction pipe negative pressure is the largest, actuator 1
1, the control valve 10 is closed, and the valve body 18 of the control valve 10 is in an inclined state with only the primary side suction port 4 slightly open, as shown in (a). Therefore, the air-fuel mixture from the carburetor 9 is deflected in the cylinder tangential direction by the valve body 18 of the control valve 10 and guided to the outlet side of the primary side suction port 4, and the flow rate is increased according to the opening degree and flows into the cylinder. The inflow creates a strong swirl. Then, in the partial state, as the suction pipe negative pressure becomes smaller, the control valve 10 is operated by the actuator 11 in the opening direction. Therefore, as shown in (b), the inclination of the valve body 18 of the control valve 10 gradually decreases,
The opening degree of the primary side suction port 4 is increased, and the secondary side suction port 5 begins to open, and air is taken in from both suction ports 4.5. Incidentally, since a large amount of air is preferentially taken in from the primary side suction port 4 and also has the effect of being deflected in the cylinder tangential direction by the valve body 18, a swirl occurs depending on the load. Furthermore,
When the throttle is fully opened, the suction pipe negative pressure becomes approximately equal to atmospheric pressure, and the valve body 18 of the control valve 10 is actuated by the actuator 11.
is horizontal as shown in (C) and both suction ports 4.5 are fully opened, so air is equally taken in from both suction ports 4.5 with little suction resistance. Although one embodiment of the present invention has been described above, it is also applicable to an injector type internal combustion engine, and it is also possible to use actuators other than the diaphragm type.

【Effect of the invention】

As is clear from the above explanation, according to the intake system of the present invention, the intake ports on the primary side and the secondary side are configured to branch into a three-pronged shape, and the control valve preferentially selects the intake ports from the primary side. As the air is taken in, it is deflected in the tangential direction of the cylinder, and swirl is generated even during partial operation, so the combustion efficiency in this case also improves, making it possible to achieve lean combustion and increase EGR, which is advantageous in terms of fuel efficiency and exhaust gas purification. Become. At low and high loads, it has the same performance as the conventional two-intake valve type. The lateral movement of the primary side suction port is simplified, and the swirl generation state can be easily changed by changing the shape of the control valve, etc. In the case of the embodiment, there is no need to change the intake manifold, and the control valve has good operability and is easy to adjust due to the diaphragm actuator.

[Brief explanation of drawings]

FIG. 1 is a partially sectional block diagram of an embodiment of the apparatus according to the present invention, and FIGS. 2(a) to 2(a) are diagrams showing operating states under various operating conditions. DESCRIPTION OF SYMBOLS 1... Cylinder head, 2... Combustion chamber, 3... Intake port, 4... Primary side intake port, 5... Secondary side intake port, 10... Control valve, 11... ...Actuator, A... Branching point. Figure 1

Claims (1)

[Claims] The primary and secondary suction ports each have their own intake valves and have approximately the same diameter are bifurcated into a bifurcated configuration, and a control valve is provided between both suction ports at the bifurcation point, depending on the operating conditions. An intake system for an internal combustion engine, characterized in that air is preferentially taken in from a primary side intake port and deflected in a cylinder tangential direction by opening and closing a control valve.