JPH0586871A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure a stable combustion condition and to deal with lean combustion by basically forming an intake passage both by a primary passage for low-load use and by a secondary passage for high-load use which has a larger sectional area than that of the former, and by contriving the installation of an open/close value and the constitution of the downstream end of the passage. CONSTITUTION:In a multiple cylinder internal combustion engine 2, each combustion chamber 18-1 is provided with one intake value 26-1 and with an injector 10. The intake passage 14-1 is divided into a plurality number of passages which are connected to each cylinder downstream of a throttle value 16. In this case, explaining representatively by an intake passage 14-1, this is branched midway and is formed by a primary passage 20-1 for low-load use and by a secondary passage 22-1 for high-load use which has a larger sectional area than that of the former. Downstream of the branch part of the secondary passage 22-1, a secondary valve 24-1 is openably arranged. Further, the downstream end of the primary passage 20-1 is opened directly before the intake valve 26-1 and also it is directed toward the circumferential direction of the combustion chamber 18-1 on the ignition plug side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly to an internal combustion engine of a multi-cylinder internal combustion engine in which one intake valve is provided and a single point injector is provided in the intake passage. Regarding an intake device of an engine.

[0002]

2. Description of the Related Art In an intake system of an internal combustion engine, an air cleaner 108, an injector 110, a throttle valve 116, and an intake valve 126 are sequentially arranged from the upstream side, as shown in FIG. 7, for example, a cylinder head 104 and a cylinder block. An air-fuel mixture is supplied into a combustion chamber 118 formed by 106 through an intake passage 114.

Further, as shown in FIG. 8, a spark plug 128 is disposed at an eccentric position in the combustion chamber 118, and a downstream end 114b of the intake passage 114 is formed so as to be directed toward the spark plug 128. Reference numeral 130 is an exhaust valve.

As an intake device for the internal combustion engine, there is one disclosed in Japanese Utility Model Laid-Open No. 54-56006. The internal combustion engine disclosed in this publication has an intake system arranged to form a swirl flow in the combustion chamber during an intake stroke, and a jet port connected to a compressed air source that supplies air of a constant pressure and opening to the combustion chamber. The flow of the air jetted in the direction of the jet port for jetting air into the combustion chamber is formed to promote the swirling flow, and a valve that opens against the pressure of the combustion chamber during the compression stroke is provided.

[0005]

In the conventional intake system for an internal combustion engine, however, a vertical vortex or swirl is formed in the combustion chamber by the air-fuel mixture flowing from the downstream end of the intake passage into the combustion chamber.

However, since the longitudinal vortex or swirl formed in the combustion chamber is weak, the mixture in the combustion chamber is not sufficiently disturbed.

As a result, the propagation of the combustion flame in the combustion chamber is delayed, a stable combustion state cannot be ensured, and lean combustion cannot be supported.

[0008]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention has an internal combustion engine having a single-point injector with one intake valve in each combustion chamber of a multi-cylinder internal combustion engine. In the intake system of
The intake passage of the internal combustion engine is formed by a low-load primary side passage and a high-load secondary side passage having a passage sectional area larger than that of the low-load primary side passage. An on-off valve that opens and closes the high-load secondary passage is provided in the middle of the passage and downstream of the branch point between the low-load primary passage and the high-load secondary passage. It is characterized in that the downstream end of the passage is opened immediately before the intake valve and is directed toward the spark plug in the combustion chamber and in the circumferential direction of the combustion chamber.

[0009]

With the invention as described above, the open / close valve is closed in the low load / low rotation range, and the air-fuel mixture flows into the combustion chamber only from the low load primary side passage. The air-fuel mixture having a high flow velocity flows into the combustion chamber through the primary passage, forming a strong swirl in the combustion chamber 18-1.

[0010]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show a first embodiment of the present invention. 1 to 3, 2 is a multi-cylinder, for example, 4-cylinder internal combustion engine, 4 is a cylinder head, 6 is a cylinder block, 8 is an air cleaner, 10 is a single-point injector, and 12 is an intake manifold.

An intake passage 14 is provided in the intake manifold 12.
Is formed, and one throttle valve 16 is disposed in the intake passage 14 downstream of the injector 10 by a throttle body (not shown).

The intake passage 14 on the downstream side of the throttle valve 16 is connected to each cylinder # 1, # 2, # 3, #.
4 intake passages 14-1, 14-2, 14 communicating with No. 4
-3 and 14-4.

From here on, in accordance with FIGS. 1 and 2, the cylinder #
Although only the intake passage 14-1 communicating with No. 1 will be described, the intake passages 14-2, 14-3, 14-4 communicating with the other cylinders # 2, # 3, # 4 are also referred to as the intake passage 14-1. It has a similar configuration.

The intake passage 14-1 communicates with the combustion chamber 18-1 formed in the cylinder # 1 and branches in the middle of the intake passage 14-1 to form a low load primary passage 20-1. The high-load secondary passage 22-1 having a passage cross-sectional area larger than that of the low-load primary passage 20-1 and the intake passage 14-1.
To form.

That is, as is clear from FIGS. 1 to 3, the high load secondary passage 22-1 is formed to have a passage cross-sectional area substantially equal to that of the upstream intake passage portion. From the secondary passage 22-1 to the small-diameter primary passage 20-1 for low load
Are formed in a branched state.

In the middle of the high load secondary passage 22-1,
Further, it is an opening / closing valve 2 for opening and closing the high load secondary side passage 22-1 on the downstream side slightly below the branch portion between the low load primary side passage 20-1 and the high load secondary side passage 22-1. A secondary valve 24-1 is provided, and the secondary valve 24-1 is in a closed state in a low load low rotation range (practical range) and starts to open when shifting to a relatively high load high rotation range, and the full load is reached. It is in a fully opened state in the area.

When the four secondary valves 24-1, 24-2, 24-3, 24-4 are arranged in the internal combustion engine 2, they are parallel to the internal combustion engine 2 and substantially They are arranged in a straight line.

The downstream end 20b-1 of the low load primary side passage 20-1 is opened just before one intake valve 26-1 and the spark plug 2 in the combustion chamber 18-1 is opened.
It is configured so as to be directed toward the 8-1 side and in the circumferential direction of the combustion chamber 18-1.

More specifically, the low-load primary side passage 20-1
Downstream end portion 20b-1 of the valve is opened immediately before the intake valve 26-1, that is, in the immediately upstream portion, and is directed toward the spark plug 28-1 side eccentrically provided in the combustion chamber 18-1. And is formed so as to be oriented in the circumferential direction of the combustion chamber 18-1.

Reference numeral 30-1 is an exhaust valve provided in the internal combustion engine 2.

Next, the operation will be described.

In the low load and low speed range, which is the practical range, the secondary valve 24-1 is closed, and the air-fuel mixture enters the combustion chamber 18-1 only from the low load primary side passage 20-1. Be flowed in.

At this time, the small-diameter low-load primary side passage 20
-1 causes the air-fuel mixture having a large flow velocity to flow into the combustion chamber 18-1, and a strong swirl is generated in the combustion chamber 18-1 as indicated by the thick black arrow in FIG.

In the relatively high load and high rotation range,
As the secondary valve 24-1 starts to open, the high load secondary passage 2 together with the low load primary passage 20-1.
The air-fuel mixture also flows into the combustion chamber 18-1 from 2-1.

Further, in the full load range, the secondary valve 24-1 is fully opened and a sufficient mixture is generated in the combustion chamber 18.
Since it will be flown into -1, there is no fear of impairing the performance of the conventional internal combustion engine.

As a result, the air-fuel mixture having a high flow velocity can be made to flow into the combustion chamber 18-1 by the small-load primary-side passage 20-1 having a small diameter in the low-load low-rotation region.
A powerful swirl can be generated in -1.

Further, since the swirl formed in the combustion chamber 18-1 is stronger than in the conventional case, the air-fuel mixture in the combustion chamber 18-1 is sufficiently disturbed and the swirl in the combustion chamber 18-1 is increased. Propagation of the combustion flame becomes faster and a stable combustion state can be secured, which is practically advantageous.

Further, since it becomes possible to deal with lean burn by ensuring a stable combustion state, it is possible to improve fuel efficiency performance and exhaust gas performance.

Furthermore, since the internal combustion engine 2 has a relatively simple structure, it is easy to manufacture, the cost can be reduced, and it is economically advantageous.

4 to 6 show a second embodiment of the present invention. In the second embodiment, the portions having the same functions as those in the first embodiment will be described with the same reference numerals.

The feature of the second embodiment is that the induction air passage 40 is provided in the first embodiment.

That is, in the induction air passage 40 formed in the internal combustion engine 2, the starting end 40a opens near the throttle valve 16 and each cylinder # 1, # 2, #.
3, # 4 intake valves 26-1, 26-2, 26-3, 26
-4 (the description of 26-2, 26-3, and 26-4 is omitted below), the terminal end 40b opens.

In addition, the induction air passage 40 is similar to the above-mentioned low load primary side passage 20-1 and the intake valve 2 is provided.
Immediately before 6-1 or in other words, it is formed to end toward the upstream side, and is formed so as to be directed to the spark plug 28-1 side eccentrically provided in the combustion chamber 18-1 and the circumferential direction of the combustion chamber 18-1. Is formed to point to.

Further, the induction air passage 40 has two
Combustion chamber 18 of cylinder # 14 near the secondary valve 24-1
1 has a branch passage portion 40-1 to communicate with 1.

By the way, in the low load and low rotation range which is the practical range, the secondary valve 24-1 is in the closed state,
The air-fuel mixture flows into the combustion chamber 18-1 from the low load primary side passage 20-1 and the induction air passage 40.

At this time, the small-diameter primary passage 20 for low load is used.
-1 and the induction air passage 40 cause a mixture having a high flow velocity to flow into the combustion chamber 18-1.
As shown by the thick black arrow in FIG. 5, it is possible to generate a more powerful swirl in the combustion chamber 18-1 as compared with the conventional one.
Similar to the first embodiment, the air-fuel mixture is sufficiently disturbed in the combustion chamber 18-1, the propagation of the combustion flame in the combustion chamber 18-1 is accelerated, and a stable combustion state is secured. Therefore, it is possible to cope with lean combustion and improve fuel efficiency performance and exhaust gas performance.

Further, since the internal combustion engine 2 has a relatively simple structure, it is easy to manufacture, the cost can be reduced, and it is economically advantageous.

Further, in a relatively high load and high rotation range,
Since the secondary side valve 24-1 starts to open, the air-fuel mixture also flows from the high load secondary side passage 22-1 to the combustion chamber 18-1.
Flows into the inside, and in the entire load range, the secondary valve 24
-1 is fully opened and a sufficient mixture is generated in the combustion chamber 18-1.
Since it will flow into the inside, there is no fear of impairing the performance of the conventional internal combustion engine.

Furthermore, in idling, a mixture of some percentage of the intake air amount of idling is directly sucked from the induction air passage 40 into the combustion chamber 18-1.

[0041]

As described above in detail, according to the present invention, the intake passage of the internal combustion engine has a high load having a primary passage for low load and a passage sectional area larger than that of the primary passage for low load. Secondary passage for high load, which is formed in the middle of the secondary passage for high load and downstream of the branch point between the primary passage for low load and the secondary passage for high load. A low-load primary side passage is provided with an opening / closing valve for opening the downstream end immediately before the intake valve and is configured to be directed to the spark plug side in the combustion chamber and in the circumferential direction of the combustion chamber. In the low-load low-speed region, a small-diameter primary passage for low load allows a high-velocity mixture to flow into the combustion chamber, creating a powerful swirl in the combustion chamber. Is sufficiently disturbed and the combustion flame propagates quickly in the combustion chamber. Ri, it is possible to ensure a stable combustion state, which is advantageous in practical use. Further, since it becomes possible to deal with lean combustion by ensuring a stable combustion state, it is possible to improve fuel efficiency performance and exhaust gas performance. Furthermore, since the internal combustion engine has a relatively simple structure, it is easy to manufacture, the cost can be reduced, and it is economically advantageous.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part of an intake system for an internal combustion engine showing a first embodiment of the present invention.

FIG. 2 is a bottom view of a cylinder head showing a swirl formation state in cylinder # 1.

FIG. 3 is a plan view of an internal combustion engine.

FIG. 4 is an enlarged sectional view of an essential part of an intake device for an internal combustion engine showing a second embodiment of the present invention.

FIG. 5 is a bottom view of the cylinder head showing a swirl formation state in cylinder # 1.

FIG. 6 is a plan view of an internal combustion engine.

FIG. 7 is an enlarged view of a main part of an intake device for an internal combustion engine showing a conventional technique of the present invention.

FIG. 8 is a bottom view of the cylinder head.

[Explanation of symbols]

 2 Internal combustion engine 10 Injector 14-1 Intake passage 16 Throttle valve 18-1 Combustion chamber 20-1 Low-load primary side passage 20b-1 Downstream end 22-1 High-load secondary side passage 24-1 Secondary Side valve 26-1 Intake valve 28-1 Spark plug

Claims (1)

[Claims] 1. An intake system for an internal combustion engine having a single-point injector having one intake valve in each combustion chamber of a multi-cylinder internal combustion engine, wherein an intake passage of the internal combustion engine has a low-load primary side. A high-load secondary passage having a passage cross-sectional area larger than that of the low-load primary passage, and is in the middle of the high-load secondary passage and the low-load primary passage and the high load. An opening / closing valve for opening and closing the high-load secondary passage is provided downstream of the branch point with the secondary secondary passage, and the downstream end of the low-load primary passage is opened immediately before the intake valve. At the same time, the intake device for an internal combustion engine is configured so as to be directed toward the spark plug in the combustion chamber and in the circumferential direction of the combustion chamber.