JP2523564Y2 - Intake device for internal combustion engine - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) In this invention, one combustion chamber has multiple intake ports,
In particular, the present invention relates to three intake devices for an internal combustion engine.

(Prior Art) As this type of conventional intake device, there is, for example, one described in Japanese Utility Model Laid-Open Publication No. Sho 62-31725 shown in FIG. This is because, in the low engine load range, the mixture around the spark plug above the combustion chamber is enriched and the piston side is thinned, so-called stratification of combustion, thereby expanding the lean limit of the combustible air-fuel ratio and improving combustion, The aim is to improve fuel efficiency.

The main intake port 1 in this intake device is provided with a first intake port 5, a second intake port 7,
Are branched into three intake ports 9. Of these, the first intake port 5 is a normally open port that generates swirl in the intake air supplied into the combustion chamber 3,
The intake port 7 has a control valve 11 that opens only in a high load region of the engine, and supplies straight intake air into the combustion chamber 3. The main intake port 1 has
1, the injection fuel is directed to each of the second intake ports 5, 7,
First fuel injection valve for injecting fuel only into a high load region of an engine
13 are provided. On the other hand, the third intake port 9 opens toward the vicinity of the ignition plug 15, and the intake port 9 is provided with a second fuel injection valve 17 for injecting fuel into a low load region of the engine. The first and second fuel injection valves 13 and 17 are controlled by a control unit 19.

Therefore, by adopting such a configuration, fuel can be injected from the second fuel injection valve 17 toward the vicinity of the ignition plug 15 in the low engine load region, so that the mixture is rich around the ignition plug 15 and the piston side The stratification of lean combustion becomes possible.

On the other hand, in Japanese Utility Model Laid-Open No. 18336/1987, a flat portion that is perpendicular to the valve stem is formed at the head of an intake valve that opens and closes a third intake port located at the center of the three intake ports. The intake air is guided to the ignition plug to facilitate the flow to the ignition plug side, thereby enriching the air-fuel mixture around the ignition plug to stratify combustion.

Japanese Utility Model Laid-Open No. 62-117229 discloses a single point injection type in which one fuel injection valve is provided upstream of a throttle valve provided in a main intake port. In the load region, fuel (air-fuel mixture) is supplied only to the third intake port located at the center of the three intake ports to stratify combustion.

(Problems to be Solved by the Invention) However, in such a conventional intake device for an internal combustion engine, fuel is supplied only from the third intake port 9 to the engine low load region, and this fuel is supplied to the ignition plug 15 side. The ignition plug 15 is easily smoldered by the injected fuel, the unburned fuel increases to deteriorate the operability, and the swirl is generated in the combustion chamber 3 in a low load region. Since the intake air flows from the third intake port 9 in addition to the intake port 5, the inflow intake air weakens the swirl caused by the first intake port 5, and there is a problem that sufficient combustion efficiency cannot be obtained. .

Accordingly, an object of the present invention is to provide an intake device for an internal combustion engine that prevents smoldering of an ignition plug due to injected fuel and can maintain a good swirl in a combustion chamber in a low load region.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-described problems, the present invention provides a first intake port that opens along the peripheral wall of the combustion chamber, a second intake port, and a combustion chamber. A fuel injection valve that forms three intake ports with a third intake port that opens toward the center provided with the ignition plug from the main intake port toward the combustion chamber, and supplies fuel to the combustion chamber, The injection port is directed to both the first and second intake ports except the third intake port, and the main intake port is closed in an engine low load range and the second and third intake ports are closed. A control valve that restricts intake air flowing into each intake port and opens in a high engine load region is provided.

(Operation) According to such a configuration, the intake air flowing into each of the second and third intake ports is restricted in the engine low load region where the control valve is fully closed, and mainly along the peripheral wall of the combustion chamber. The intake air is guided to the opening first intake port and flows into the combustion chamber, and strong swirl is generated in the combustion chamber.

In addition, the supplied fuel does not completely flow into the combustion chamber,
The control valve is fully closed and the intake air flowing into the third intake port changes from a state in which floating fuel remains in the third intake port and the main intake port to a low load operation. Is limited, so that the above-mentioned floating fuel
Does not flow into the combustion chamber so as to hit the ignition plug directly from the intake port of the fuel injection valve.
In addition to being considered for each intake port,
The smoldering of the spark plug is effectively prevented in a low load region where the temperature in the combustion chamber is lower than in a high load region.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

1 and 2 show a first embodiment of the present invention.
First, second, and third intake ports 23, 25, and 27 are formed in a cylinder head 21 of the vehicle internal combustion engine, and first and second exhaust ports 29, 31 are formed, respectively. I have. First, second and third intake ports 23, 25 and 27
Can communicate with the combustion chamber 39 via the first, second and third intake valves 33, 35 and 37, and can communicate with the first and second exhaust ports 2
9 and 31 can communicate with the combustion chamber 39 via the first and second exhaust valves 41 and 43. In addition, each intake valve 33, 35, 37 and each exhaust valve 41, 4
A spark plug 45 is attached to the cylinder head 21 in the area surrounded by 3.
Is installed.

The first and second intake ports 23 and 25 open along the inner peripheral wall of the combustion chamber 39, while the third intake port 27 opens substantially toward the center of the combustion chamber 39. 23, 25, 27 communicate with a main intake port 47 in the cylinder head 21 and an intake passage 50 in an intake manifold 49 on the upstream side.

The intake passage 50 is provided with a control valve 51 that can be opened and closed according to the operating state of the engine. The control valve 51 is fixed to a valve shaft 53 rotatably mounted on the intake manifold 49, and the valve shaft 53
Is connected to an actuator such as a negative pressure diaphragm device (not shown) operated by, for example, suction negative pressure, and rotates the control valve 51 so as to close the low engine load region and open the high valve load region.

The control valve 51 is formed with a notch 51a that is aligned with the first intake port 23 on the downstream side when the control valve 51 is fully closed.
Is passed through the first intake port 23 to the combustion chamber 39.
Generate strong swirl.

A fuel injection valve 57 whose front end faces the main intake port 47 on the cylinder head 21 side is mounted in a mounting hole 55 above the intake manifold 49 near the control valve 51. The tip of the fuel injection valve 57 is located in a recess 59 of the cylinder head 21 formed continuously with the mounting hole 55. On the other hand, the control valve 51 is formed with an arc-shaped projection 61 that enters the recess 59 when fully closed,
An opening 63 is formed in the projection 61 so that the tip of the fuel injection valve 57 is aligned when the control valve 51 is fully closed.

Two injection ports 65, 67 are provided at the tip of the fuel injection valve 57, and the injection port 65 is directed to the first intake port 23, and the injection port 67 is directed to the second intake port 25.

In the intake device for an internal combustion engine having such a configuration, the control valve 51 is fully closed in a low engine load region. At this time, the intake air passes through the cutout portion 51a of the control valve 51, and the main flow thereof flows through the first intake port 23. And flows into the combustion chamber 39 to generate a strong swirl that is optimal for a low load region, so that sufficient combustion efficiency can be obtained. On the other hand, fuel is separately injected from the injection ports 65 and 67 of the fuel injection valve 57 through the opening 63 toward the first intake port 23 and the second intake port 25, respectively. As a result, the fuel is hardly guided to the combustion chamber 39 from the third intake port 27, which easily hits the ignition plug 45, so that the smoldering of the ignition plug 45 is prevented, the unburned fuel is reduced, and the deterioration of drivability is prevented. Is done.

In the high engine load range, the control valve 51 is fully opened and intake
A large amount is introduced into the combustion chamber 39 through the first, second and third intake ports 23, 25 and 27, whereby sufficient intake charging efficiency is obtained and output is improved. At this time, the injection ports 65, 67 of the fuel injection valve 57
Thereafter, the fuel is separately injected toward the first intake port 23 and the second intake port 25 as in the low load range, so that the smoldering of the ignition plug 45 is also prevented in this operation range.

Further, the supplied fuel cannot flow into the combustion chamber 39,
1, second and third intake ports 23, 25, 27 and main intake port 47
When the operation shifts from the state where the fuel remains as floating fuel to the low load operation in which the control valve 51 is fully closed, the third
The intake air flowing into the intake port 27 is restricted,
The floating fuel does not flow into the fuel chamber 39 so as to hit the spark plug 45 directly from the third intake port 27,
45 smoldering is prevented.

As described above, in the low engine load region where the control valve 51 is fully closed, the direct impact of fuel on the spark plug 45 is further prevented than in the high engine load region. Since the temperature is lower than that in the high load range, smoldering may occur even if the fuel droplets having a small particle diameter such as floating fuel are hit directly, so it is extremely effective in preventing smoldering of the spark plug 45. is there.

FIG. 3 shows a second embodiment. In this embodiment, the control valve 69
Next, an example is shown in which a projection and an opening are not provided as in the first embodiment. Other configurations are the same as those of the first embodiment. Therefore, also in this case, the first intake port 23 and the second
Are separately injected toward the two intake ports corresponding to the intake ports 25 of the spark plug 45, thereby preventing the smoldering of the spark plug 45,
Drivability is improved. However, in this example, when the control valve 69 is fully closed, part of the fuel is deflected by the intake air ejected from the gap 70 between the control valve 69 and the inner wall of the intake passage 50 and adheres to the wall surface 71. While the air-fuel ratio is thinned due to a supply delay, there is a drawback that misfiring easily occurs. On the other hand, since the projection and the opening are not formed in the control valve 69, the manufacturing cost is reduced.

FIG. 4 and FIG. 5 show a third embodiment. In this embodiment, a control valve 73 is provided on the cylinder head 21 side, and a first fuel injection valve 75 and a second fuel injection valve 77 are provided in parallel in an intake manifold 49 on the upstream side thereof. Control valve 73
A notch 79 which is aligned with the first intake port 23 when fully closed is formed, and the intake air passing through the notch 79 is guided to the first intake port 23 to generate a strong swirl in the combustion chamber 39. The first fuel injection valve 75 has one injection port 81, and the injection port 81 is directed to the cutout portion 79 and the first intake port 23 when the control valve 73 is fully closed. Inject fuel in all operating ranges over load. On the other hand, the second fuel injection valve 77 has two nozzles.
The fuel injection ports 83 and 85 are respectively directed to the first intake port 23 and the second intake port 25, and inject fuel into a high engine load region where the control valve 73 is fully opened. . Other configurations are the same as those of the first embodiment, and the same components as those of the first embodiment are denoted by the same reference numerals.

In the intake device for an internal combustion engine having such a configuration, the control valve 73 is fully closed as shown in FIG. Guided to the intake port 23, a strong swirl optimal for a low load region is generated in the combustion chamber 39, and sufficient combustion efficiency can be obtained. At this time, the fuel is injected only from the first fuel injection valve 81, and the injected fuel flows into the combustion chamber 39 through the notch 79 and the first intake port 23. As a result, the fuel is hardly guided to the combustion chamber 39 from the third intake port 27 that easily hits the ignition plug 45, so that the smoldering of the ignition plug 47 is prevented, the unburned fuel is reduced, and the operability is improved.

On the other hand, in the high engine load region, the control valve 73 is fully opened, and a large amount of intake air is introduced into the combustion chamber 39 through the first, second, and third intake ports 23, 25, and 27, and sufficient intake charge is provided. Efficiency is obtained and output is improved. At this time, fuel is also injected from the second fuel injection valve 77, and this injected fuel is supplied to the first intake port 77.
Since the fuel flows toward the second intake port 25 and the second intake port 25, a small amount of fuel directly hits the spark plug 45 as in the low load range, and smoldering of the spark plug 45 is prevented.

In the third embodiment, the second fuel injection valve
77 may be provided downstream of the control valve 73.

FIG. 6 shows a fourth embodiment. In the figure, a first intake port 87 is divided by a partition wall 89 into second and third intake ports 9.
1,93, and the second and third intake ports 91,93
Are separated from each other by a partition 95 located downstream of the partition 89. Each of the intake ports 87, 91, and 93 communicates with a main intake port 97 upstream thereof.

The first intake port 87 has a first fuel injection valve 99 for injecting fuel in an entire operation range from a low engine load region to a high engine load region.
The first intake port 87 opens along the inner peripheral wall of the combustion chamber 101, and the combustion chamber 101 generates a strong swirl by the intake air guided from the intake port 87. on the other hand,
An upstream side of the second intake port 91 is provided with a second fuel injection valve 103 that injects fuel only in a high engine load region. Each of the first and second fuel injection valves 99 and 103 injects fuel by a drive pulse output from the control unit 105. A control valve 107 is provided near the upstream end of the partition wall 89 on the upstream side of the second intake port 91 and the third intake port 93. The control valve 107 is opened and closed by, for example, a negative pressure actuator (not shown) operated by a suction negative pressure so as to close in a low engine load region and open in a high engine load region. 109 and 111 are the first
And the second exhaust port 113 is an ignition plug.

In the engine low load region, the control valve 107 is fully closed, and fuel injection is performed only from the first fuel injection valve 99. As a result, the intake air is guided to the first intake port 87 to generate a strong swirl optimal for a low load region in the combustion chamber 101 to improve the combustion efficiency, and the fuel easily hits the spark plug 113 directly. Does not flow from the intake port 93, so that smoldering of the ignition plug 113 is prevented, unburned fuel is reduced, and operability is improved.

In the high engine load region, the control valve 107 opens, and the fuel injection
In addition to the fuel injection valve 99, the operation is also performed from the second fuel injection valve 103. As a result, the intake air is supplied to the combustion chamber 101 from the second and third intake ports 91 and 93 in addition to the first intake port 87, so that sufficient intake charging efficiency is obtained and the output is improved. At the same time, also in this case, since no fuel flows into the third intake port 93, the smoldering of the ignition plug 113 is prevented, and the operability is improved.

In each of the second, third, and fourth embodiments, similarly to the first embodiment, the control valves 69, 73, 107 are changed from a state in which the floating fuel remains in the main intake ports 47, 97. When the operation is shifted to the low-load operation in which the third intake port is fully closed, the third intake port 27,93
By restricting the intake air flowing into the ignition plug, the above-described effect of preventing the floating fuel from directly hitting the ignition plug 45 and preventing the smoldering of the ignition plugs 45 and 113 is obtained.

[Effects of the Invention] As described above, according to the invention, the first intake port opened along the peripheral wall of the combustion chamber and the fuel intake valve whose injection port is directed to the second intake port are provided. , Is fully closed in the engine low load range, and when fully closed,
The following effects are obtained by providing the restriction valves for restricting the intake air flowing into the second intake port and the intake air flowing into the third intake port opening toward the ignition plug.

In the low engine load region where the control valve is fully closed, the intake air flowing into each of the second and third intake ports is restricted, and the intake air is mainly introduced to the first intake port that opens along the peripheral wall of the combustion chamber. As a result, a strong swirl is generated in the combustion chamber, and sufficient combustion efficiency can be obtained.

When the control valve is fully closed, the intake air flowing into the third intake port is restricted, so that the supplied fuel cannot completely flow into the combustion chamber, and as a floating fuel in each of the first to third intake ports and the main intake port. Even when the operation is shifted from the remaining state to the low-load operation, such floating fuel does not flow into the combustion chamber from the third intake port so as to directly hit the spark plug, and the fuel injected by the fuel injection valve does not flow. Combined with the fact that the injection is directed only to the first and second intake ports, the smoldering of the spark plug is effectively prevented in a low-load region where the temperature in the combustion chamber is lower than in a high-load region. can do.

[Brief description of the drawings]

FIG. 1 is a partial plan sectional view of the intake device of an internal combustion engine according to a first embodiment of the present invention, as viewed from the bottom side of a cylinder head;
FIG. 2 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is a longitudinal sectional view of a main part of the second embodiment of the invention, and FIG. 4 is a first embodiment of the third embodiment of the invention. 5 is a sectional view taken along line VV of FIG. 4, FIG. 6 is a plan sectional view of an intake device of an internal combustion engine according to a fourth embodiment of the present invention, FIG. The figure is a cross-sectional view of the same conventional plane. 23 first intake port 25 second intake port 27 third intake port 39 combustion chamber 45 ignition plug 47 main intake port 51 control valve 51a Notch (communication part) 57: Fuel injection valve

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location F02M 69/00 360 F02M 69/00 320F

Claims (1)

(57) [Scope of request for utility model registration] A first intake port that opens along a peripheral wall of the combustion chamber, a second intake port, and a third intake port that opens toward a substantially center where a spark plug of the combustion chamber is provided. The three intake ports are formed so as to branch from the main intake port toward the combustion chamber, and the fuel injection valve that supplies fuel to the combustion chamber has an injection port that is different from the first and second intake ports except for the third intake port. The main intake port has a control valve that closes in a low engine load region and restricts intake air flowing into each of the second and third intake ports and opens in a high engine load region. An intake device for an internal combustion engine, wherein the intake device is provided.