JPH09222063A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a wall flow as a result of fuel injected through an injector being adhered on the wall surface of an intake passage. SOLUTION: In the intake device of an internal combustion engine comprising an intake air flow control valve 8 to throttle an intake passage according to an operation condition; and a guide groove 21 dented in a groove-form state in an intake passage wall surface 20 and causing the flow of intake air during closing of a an intake air flow control valve 8, an injector 3 is arranged such that the fuel spray central line O3 thereof crosses the central line O2 of the guide groove 21 in arc intake port 11 situated right upper stream from a combustion chamber 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of an intake system for an internal combustion engine.

[0002]

2. Description of the Related Art In an engine in which fuel injected from an injector into an intake passage is mixed with intake air and sucked into a combustion chamber, the fuel injected from the injector is prevented from adhering to the wall surface of the intake passage and forming a wall flow. Required to do so.

As a conventional intake device for an internal combustion engine, there is one as shown in FIG. 7 (see Japanese Utility Model Laid-Open No. 61-80365).

An auxiliary air passage 104 having one end opened near the fuel injection port of the injector 103 and the other end opened at the intake passage 101 upstream of the air flow control valve 102 is provided.

Due to the pressure difference generated before and after the air flow control valve 102, the auxiliary air, which is a part of the intake air, is guided to the fuel injected from the injector 103 through the auxiliary air passage 104, and the fuel sucked into the cylinder is discharged. It is designed to promote atomization.

When the air flow control valve 102 is closed, most of the intake air is guided through the cutouts of the air flow control valve 102, so that the intake air flow velocity flowing into the combustion chamber 1 is increased and the combustion chamber 1 is increased. It is designed to generate an intake swirl flow.

[0007]

However, in such a conventional intake system for an internal combustion engine, the intake flow control valve 1 is operated when the intake flow control valve 102 is closed.
There is a problem that the fuel spray injected from the injector 103 is deflected by the high-speed air flow passing through the notch 02 and adheres to the upper part of the wall surface of the intake passage located in front of the injector 103 to easily become a wall flow. .

When a wall flow of fuel occurs on the wall surface of the intake passage, the control responsiveness of the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber deteriorates at the transition of changes in the fuel injection amount. Further, atomization of fuel may be hindered, which may lead to deterioration of emission and fuel efficiency.

It is an object of the present invention to solve the above problems and prevent the fuel injected from the injector from adhering to the wall surface of the intake passage to form a wall flow in the intake system of the internal combustion engine.

[0010]

An intake system for an internal combustion engine according to claim 1, wherein an intake passage for guiding intake air into a combustion chamber, an intake flow control valve for narrowing the intake passage in accordance with operating conditions, and an intake passage wall surface. In the intake device of an internal combustion engine, which is provided with a guide groove that is recessed in a groove shape for passing intake air when the intake flow control valve is closed, and an injector that injects fuel into the intake passage,
The injector is arranged so that the center line of the fuel spray intersects the center line of the guide groove in the combustion chamber or the intake passage immediately upstream of the combustion chamber.

According to a second aspect of the present invention, there is provided an intake system for an internal combustion engine.
In the invention of claim 1, the intersection of the fuel spray center line of the injector and the guide groove center line is arranged near the opening end of the intake passage to the combustion chamber.

According to a third aspect of the present invention, there is provided an intake device for an internal combustion engine.
In the invention of claim 1, the intersection of the fuel spray center line of the injector and the center line of the guide groove is arranged at the downstream end of the guide groove.

According to a fourth aspect of the present invention, there is provided an intake device for an internal combustion engine.
In the invention according to claim 1, the fuel injection port of the injector is made to face the middle of the guide groove.

[0014]

In the intake system for an internal combustion engine according to claim 1, in an operating state in which the intake flow control valve is open, the intake flow control valve does not throttle the intake flow and mixes with the fuel spray injected from the injector. While being sucked into the combustion chamber, the air-fuel mixture is made uniform.

In the operating state in which the intake flow control valve is closed, most of the intake air is collected in the guide groove. At this time,
The fuel injected from the injector is injected toward the high-speed intake air flow that flows through the guide groove on the combustion chamber or immediately upstream of the combustion chamber, and joins with the high-speed intake air flow to promote atomization of the fuel spray. In addition, the fuel spray is prevented from adhering to the wall surface of the intake passage and forming a wall flow.

In this way, in order to prevent the wall flow of fuel from occurring on the wall surface of the intake passage, the control response of the air-fuel ratio is improved during the transition when the fuel injection amount changes. Further, since atomization of the fuel is promoted, the emission can be improved and the fuel consumption can be reduced. In the intake device for an internal combustion engine according to claim 2, the fuel injected from the injector is injected toward a high-speed intake flow flowing into the combustion chamber through the guide groove in the vicinity of the opening end of the intake passage to the combustion chamber. However, in the operating state where the intake flow control valve is closed, the atomization of the fuel spray is promoted by merging with the high-speed intake flow that flows into the combustion chamber through the guide groove.
The fuel spray is prevented from adhering to the wall surface of the intake passage to form a wall flow.

In the intake system for an internal combustion engine according to claim 3, the fuel injected from the injector is injected toward the downstream end of the guide groove, is deflected through the wall surface of the intake passage, and then flows into the combustion chamber. In the operating state where the intake flow control valve is closed, the atomization of the fuel spray is promoted by merging with the high-speed intake flow flowing along the guide groove, and the fuel spray adheres to the wall surface of the intake passage to cause wall flow. To prevent

In the intake system for an internal combustion engine according to claim 4, the fuel injected from the injector is injected in the middle of the guide groove, but at a high speed that flows in the guide groove in an operating state in which the intake flow control valve is closed. Combining with the intake air flow promotes atomization of the fuel spray and prevents the fuel spray from adhering to the wall surface of the intake passage to form a wall flow.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the combustion chamber wall 18 of the cylinder head 10 is formed to be inclined in a pent roof shape.

As shown in FIG. 2, two intake ports 11 are opened in the combustion chamber wall 18 so as to face an exhaust port (not shown) with an ignition plug 19 interposed therebetween. The cylinder head 10 has a partition wall 16 that partitions the two intake ports 11.

A valve seat (not shown) is fitted into the opening of the intake port 11 with respect to the combustion chamber 1, and the intake port 12 is opened and closed by an intake valve 12 seated on the valve seat in synchronization with engine rotation.

As the intake valve is opened, the engine inhales intake air (mixture) into the combustion chamber 1 from the intake port 11, compresses this intake air with the piston 5, ignites and burns it with the spark plug, and exhausts the exhaust valve. The exhaust gas is exhausted to each exhaust port as the valve is opened, and each of these steps is continuously repeated.

A throttle valve (not shown) is provided in the intake passage upstream of the intake port 11. The throttle valve opens and closes in conjunction with the accelerator pedal to adjust the intake air amount.

An injector 3 facing the intake port 11 is attached to the cylinder head 10. Fuel is injected from the injector 3 to the intake port 11.

The injector 3 is driven to open by a drive pulse signal output from a control device (not shown) in synchronization with engine rotation, and injects fuel adjusted to a predetermined pressure.

An intake flow control valve 8 is provided upstream of the partition wall 16 of the intake port 11. As shown in FIG. 3, the butterfly-type intake flow control valve 8 includes a valve body 15 and a valve shaft 17 that rotatably supports the valve body 15. Valve body 1
Reference numeral 5 is formed in the shape of a plate having an elliptical shape like the passage cross-section of the intake port 11.

An actuator (not shown) is connected to one end of the valve shaft 17 of the intake flow control valve 8. The intake flow control valve 8 is rotationally driven by an actuator from a fully open position that is substantially parallel to the passage centerline of the intake passage 2 to a fully closed position that is substantially orthogonal to the passage centerline of the intake passage 2.

A control device (not shown) controls the intake flow control valve 8 to be closed in a predetermined low speed and low load region in accordance with the contents of a map preset according to the operating state of the engine.

Two guide grooves 21 are formed in the intake passage wall surface 20 of the cylinder head 10 below the intake flow control valve 8 along the intake flow direction. When the intake flow control valve 8 is closed, most of the intake air is linearly guided to the combustion chamber 1 through the guide grooves 21, so that an intake swirl flow is generated in the combustion chamber 1.

Each guide groove 21 extends linearly from the upstream side of the intake flow control valve 8 to the vicinity of the valve seat. Each guide groove 21 extends in parallel with each other so as to sandwich the partition wall 16.

Each guide groove 21 extends along the combustion chamber wall 18 and the valve face of the exhaust valve which are inclined in a pent roof shape.

Each guide groove 21 is formed so that its center line O ₂ is located closer to the center of the cylinder than the center line of each intake valve. Therefore, the intake air is linearly guided to the combustion chamber wall 18 through each guide groove 21, whereby the combustion chamber 1
Intake swirling flow (tumble) that vertically swirls occurs in the central part of.

The cross-sectional shape of each guide groove 21 is substantially rectangular. Each guide groove 21 is defined by a pair of side wall portions 31 extending in the vertical direction and a bottom wall surface 32 connecting the side wall portions 31.

A concave portion 22 facing the injector 3 is formed in an upper portion of the intake passage wall surface 20 of the cylinder head 10.
The recess 22 is arranged downstream of the intake flow control valve 8 and upstream of the partition wall 16. The recess 22 defines a space through which the fuel spray injected from the injector 3 passes.

The injector 3 has two fuel injection holes. The fuel spray injected from each fuel injection port is configured to diffuse along each guide groove 21 as shown by a two-dot chain line in FIG.

For the purpose of the present invention, the center line O ₃ of each fuel spray is the center line O of each guide groove 21.
It is arranged so as to intersect with ₂ on the extension of each guide groove 21.

In this embodiment, each fuel spray center line O ₃
And each intersection point P of the center line O ₂ of each guide groove 21 is arranged near the opening end of each intake port 11 with respect to the combustion chamber 1.
In other words, the intersection point P is arranged in front of the umbrella back portion 13 of the intake valve 12 in the open state.

With the above construction, the operation will be described.

In the operating state in which the intake flow control valve 8 is opened, the intake flow control valve 8 does not throttle the flow of intake air, and is mixed with the fuel spray injected from the injector 3 and sucked into the combustion chamber 1. , The air-fuel mixture is made uniform.

When the intake flow control valve 8 is closed in a predetermined low speed and low load region, most of the intake air is collected in the guide groove 21, and the intake flow velocity is increased along the guide groove 21.

The fuel injected from the injector 3 is injected toward the front of the guide groove 21 and joins with the high-speed intake air flowing into the combustion chamber 1 through the guide groove 21 to promote atomization of the fuel spray. At the same time, the fuel spray is prevented from adhering to the wall surface 20 of the intake passage and forming a wall flow.

Since the wall flow of the fuel is prevented from occurring on the wall surface 20 of the intake passage in this way, the control response of the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber is improved at the transition when the fuel injection amount changes. Further, since atomization of the fuel is promoted, the emission can be improved and the fuel consumption can be reduced.

Under the operating conditions in which the intake flow control valve 8 is closed, the high-speed intake flow collected in the guide groove 21 is linearly guided to the central portion of the combustion chamber 1, and the combustion chamber is inclined in a pent roof type. Upon hitting the wall 18 and the valve face of the exhaust valve, a swirling flow (tumble) that swirls in the vertical direction is generated in the combustion chamber 1 as indicated by an arrow in FIG. The swirling flow generated in the combustion chamber 1 promotes the mixing of the fuel spray and the air, whereby good combustibility is obtained, and the lean burn region where the air-fuel ratio is diluted can be expanded.

Since each guide groove 21 is formed such that its center line O ₂ is located closer to the center of the cylinder than the center line of each intake valve, under the operating conditions in which the intake flow control valve 8 is closed, The air-fuel mixture is vertically swirled in the center of the combustion chamber 1, and the fuel is collected near the spark plug 19 as the piston 5 rises, so that the air-fuel mixture is stratified. As a result, good combustibility can be obtained, and the lean burn region where the air-fuel ratio is diluted can be expanded.

The same effect can be obtained by arranging each fuel spray center line O ₃ so as to intersect with the center line O ₂ of each guide groove 21 in the combustion chamber 1.

Next, another embodiment shown in FIG. 4 will be described. The parts corresponding to those in FIG. 1 are designated by the same reference numerals.

Each fuel spray center line O ₃ of the ejector 3 is directed toward the intake passage wall surface 20 of the intake port 11 so as to intersect the center line O ₂ of the guide groove 21 at the downstream end of each guide groove 21. Will be placed.

That is, each intersection point P between the fuel spray center line O ₃ and the center line O ₂ of each guide groove 21 is located in each guide groove 21.

With the above construction, the operation will be described below.

When the intake flow control valve 8 is closed in a predetermined low speed and low load region, most of the intake air is collected in the guide groove 21, and the intake flow velocity is increased along the guide groove 21.

The fuel injected from the injector 3 is injected toward the downstream end of the guide groove 21 and the intake passage wall surface 20.
The fuel spray is deflected to flow into the combustion chamber 1, but at this time, by joining with the high-speed intake flow flowing along the guide groove 21, atomization of the fuel spray is promoted, and the fuel spray is injected into the intake passage. It is prevented from adhering to the wall surface 20 and forming a wall flow.

Further, even if the fuel spray adheres to the wall surface 20 of the intake passage and becomes a wall flow in the operating state in which the intake flow control valve 8 is opened, the combustibility is not deteriorated.

Next, another embodiment shown in FIGS. 5 and 6 will be described. The parts corresponding to those in FIG. 1 are designated by the same reference numerals.

Each fuel injection port of the ejector 3 faces one of the guide grooves 21. Each fuel injection port of the ejector 3 opens on the bottom surface of the guide groove 21. Therefore, the fuel spray center line O ₃ intersects the center line of the guide groove 21 in the middle of each guide groove 21.

The configuration is as described above. Next, the operation will be described.

When the intake flow control valve 8 is closed in a predetermined low speed and low load region, most of the intake air is collected in the guide groove 21, and the intake flow velocity is increased along the guide groove 21.

The fuel injected from the injector 3 is injected in the middle of the guide groove 21 and joins with the high-speed intake air flowing through the guide groove 21, whereby the atomization of the fuel spray is promoted and the fuel spray is sucked. It is prevented from adhering to the passage wall surface 20 and forming a wall flow.

[0059]

As described above, in the intake system for the internal combustion engine according to the first aspect of the present invention, in the operating state in which the intake flow control valve is closed, the fuel is injected from the injector by the high-speed intake flow flowing through the guide groove. The atomization of the fuel spray is promoted, and the fuel spray is prevented from adhering to the wall surface of the intake passage to form a wall flow, improving the air-fuel ratio control responsiveness during a transition,
Emissions will be improved and fuel consumption will be reduced.

The intake system for an internal combustion engine according to claim 2 is
Fuel injected from the injector is injected toward the high-speed intake air flowing into the combustion chamber through the guide groove in the vicinity of the opening of the intake passage to the combustion chamber, but in the operating state in which the intake flow control valve is closed. By combining with the high-speed intake air flowing into the combustion chamber through the guide groove, atomization of the fuel spray is promoted, and the fuel spray is prevented from adhering to the wall surface of the intake passage to form a wall flow. Good flammability is obtained.

An intake system for an internal combustion engine according to claim 3 is
The fuel injected from the injector is injected toward the downstream end of the guide groove, deflects through the wall surface of the intake passage, and then flows into the combustion chamber.However, the fuel flows along the guide groove when the intake flow control valve is closed. The atomization of the fuel spray is promoted by joining with the high-speed intake air flow
It is possible to prevent the fuel spray from adhering to the wall surface of the intake passage to form a wall flow, and to obtain good combustibility.

The intake system for an internal combustion engine according to claim 4 is
The fuel injected from the injector is injected in the middle of the guide groove, and in the operating state where the intake flow control valve is closed, it joins with the high-speed intake air flow flowing through the guide groove to promote atomization of the fuel spray, and It is possible to prevent the fuel spray from adhering to the wall surface of the intake passage to form a wall flow, and to obtain good combustibility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an engine showing an embodiment of the present invention.

FIG. 2 is a plan sectional view of the same engine.

FIG. 3 is a sectional view of the intake port.

FIG. 4 is a transverse cross-sectional view of an engine showing another embodiment.

FIG. 5 is a cross-sectional view of an engine showing still another embodiment.

FIG. 6 is a plan sectional view of the same engine.

FIG. 7 is a cross-sectional view of an engine showing a conventional example.

[Explanation of symbols]

1 Combustion chamber 3 Injector 5 Piston 8 Intake flow control valve 10 Cylinder head 11 Intake port 12 Intake valve 20 Intake passage wall face 21 Guide groove O ₂ Center line of guide groove O ₃ Fuel spray center line

Claims (4)

[Claims] Claim: What is claimed is: 1. An intake passage for guiding intake air to a combustion chamber, an intake flow control valve for narrowing the intake passage according to operating conditions, and a groove recessed in a wall surface of the intake passage for intake air when the intake flow control valve is closed. In an intake system for an internal combustion engine, comprising: a guide groove that passes through; and an injector that injects fuel into the intake passage, in the injector, the fuel spray center line is located in the combustion chamber or in the intake passage immediately upstream of the combustion chamber, and An intake device for an internal combustion engine, which is arranged so as to intersect with a line. 2. The intake system for an internal combustion engine according to claim 1, wherein an intersection of a center line of the fuel spray of the injector and a center line of the guide groove is arranged near an opening end of the intake passage with respect to the combustion chamber. . 3. The intake system for an internal combustion engine according to claim 1, wherein an intersection of a fuel spray center line of the injector and a guide groove center line is arranged at a downstream end of the guide groove. 4. The intake system for an internal combustion engine according to claim 1, wherein the fuel injection port of the injector is exposed in the middle of the guide groove.