JP2002310043A - Intake air device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake air device of an internal combustion engine capable of excellently mixing fuel and air by reducing a wall surface sticking quantity of injection fuel. SOLUTION: A fuel injection nozzle 24n of a fuel injector 24 arranged downstream of an intake air flow control valve 22 in an intake pipe 21, is arranged in a position B separate from a main flow Im exceeding the main flow Im formed by the intake air flow control valve 22. The fuel is injected in the direction (the straight line AB direction) for separating from the main flow In.

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 intake system for an internal combustion engine having an intake flow control valve and a fuel injection nozzle.

[0002]

2. Description of the Related Art An intake air flow control valve is disposed downstream of a throttle valve in an intake pipe to control the air flow in the intake pipe, and fuel is injected from a fuel injection nozzle disposed downstream of the control valve to form an air-fuel mixture. Forming techniques are known.

An example of such a technique is disclosed in Japanese Patent Laid-Open No. 9-2
There is a technique disclosed in Japanese Patent No. 80066. This technology guides intake air that has passed through an intake control valve toward the wall surface on the fuel injection nozzle side from the center axis of the intake passage when the engine is warm, and transfers the intake air that has passed through the intake control valve to the intake passage when the engine is cold. Are guided toward the wall surface on the opposite side of the fuel injection nozzle from the center axis of the fuel injection nozzle. It is described that atomization of the injected fuel is promoted when the engine is warm, while the amount of fuel adhering to the inner wall surface of the intake passage can be reduced when the engine is cold. Note that the invention described below is not limited to the case where the engine is cold and the flow of the intake air (guiding direction) as in the above technology.

[0004]

When the fuel injection nozzle is arranged downstream of the intake air flow control valve, the present inventors closed the intake air flow control valve and formed a strong air flow in the intake pipe in the conventional configuration. Then, since the fuel injected from the fuel injection nozzle is injected toward the airflow from the outside of the airflow, atomization of the injected fuel does not proceed, and a good mixture of the injected fuel and the intake air is formed. It is hard. Further, in some cases, the flow of the injected fuel is deflected by the airflow and travels toward the intake pipe wall surface, and the amount of adhesion to the wall surface increases. for that reason,
It has been found that a desired combustion improvement effect cannot be obtained.

Accordingly, an object of the present invention is to provide an intake device for an internal combustion engine that reduces the amount of fuel adhering to the wall surface of the injected fuel and achieves a desired combustion improvement effect.

[0006]

In order to solve the above-mentioned problems, an intake device for an internal combustion engine according to the present invention includes an intake flow control valve in an intake pipe and a fuel injection device for injecting fuel downstream of the intake flow control valve. An intake device for an engine, wherein the fuel injection device is provided with a fuel injection nozzle projecting beyond a main intake flow formed by an intake flow control valve in an intake pipe.

With this configuration, the flow of the fuel injected from the fuel injection nozzle is hardly affected by the main flow of the intake air, and is not deflected by the flow. It is possible to reliably guide the fuel to the combustion chamber. In addition, fuel remaining near the nozzle is prevented from flowing toward the base of the injector.

[0008] Alternatively, the intake system for an internal combustion engine according to the present invention includes a fuel injection nozzle which protrudes into a main flow of an intake flow formed by an intake flow control valve in an intake pipe. It may be something.

With this configuration, the fuel can be injected in the main flow of the intake flow formed by the intake flow control valve, so that atomization of the fuel can be promoted and a good air-fuel mixture can be formed. Combustion stability can be improved. Also, since the nozzle is in the main flow of the intake air,
The amount of fuel guided to the combustion chamber can be accurately controlled without fuel adhering to the nozzle tip.

The fuel injection direction of the fuel injection nozzle is directed to the center position of the intake port arranged on the downstream side,
Alternatively, the direction is preferably toward the upper wall surface of the intake pipe downstream of the fuel injection device.

When the fuel injection direction is set in this manner, the flow direction of the fuel injected from the nozzles coincides with or follows the main flow direction of the intake flow formed by the intake flow control valve. It is less susceptible to deflection due to the main flow, and good mixing of fuel and intake air can be achieved.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In order to facilitate understanding of the description, the same constituent elements are denoted by the same reference numerals as much as possible in each drawing, and redundant description will be omitted.

FIG. 1 is a diagram showing a first embodiment of an intake device for an internal combustion engine according to the present invention. This intake device is connected to a combustion chamber 11 of a cylinder 1 of an internal combustion engine. here,
A piston 10 that is driven up and down in the figure is arranged in the cylinder 1, and a combustion chamber 11 is formed between the piston 10 and a cylinder head 12. And the intake pipe 2
An intake valve 13 is disposed at a connection portion with the exhaust pipe 31, an exhaust valve 14 is disposed between the intake pipe 13 and the exhaust pipe 31, and an ignition plug 15 is disposed at a central position above the combustion chamber 11 of the cylinder head 12.

In the intake pipe 21 constituting the intake device, in addition to a throttle valve (not shown), an intake flow control valve 22 opened and closed by an actuator 23 downstream thereof and a fuel injection device (injector) 24 for spraying fuel. Is arranged.

FIG. 1 shows a state in which the intake flow control valve 22 is closed. Even when the intake flow control valve 22 is fully closed, the intake pipe 2 is closed.
1 is not completely closed, but has a structure in which a partial passage is left on the upper wall surface side of the intake pipe 21 to reduce the cross-sectional area of the intake pipe. As a result, the flow of the airflow in the intake pipe 21 downstream of the intake flow control valve 22 when the intake dragon control valve 22 is closed is reduced by the intake flow control valve 22 as shown in FIG.
The air flows along the upper wall surface in the intake pipe 22 as shown by m. Hereinafter, this Im will be referred to as a main flow of intake air.

The fuel injection nozzle 24n of the injector 24 disposed downstream of the intake flow control valve 22 is disposed at a position B protruding from the upper wall surface of the intake pipe 21 beyond the above-described main flow Im of the intake flow and below. Have been. The fuel injection direction of the fuel injection nozzle 24n is
In the direction toward the center position A. That is, the fuel injection nozzle 24n is configured to spray fuel at a predetermined angle around the straight line AB.

According to this intake device, the fuel injection nozzle 2
Since 4n is arranged at a position away from the main flow Im of the intake flow and the fuel injection direction is a direction away from the main flow Im of the intake flow, the flow of the fuel sprayed from the fuel injection nozzle 24n is affected by the main flow Im of the intake flow. Since the flow is not deflected, the sprayed fuel can be reliably guided in the target direction, and the fuel adhesion to the wall surface of the intake pipe 21 can be suppressed. Then, by spraying in the direction of the center of the intake port 25, fuel adhesion to the wall surface of the intake pipe 21 can be further reduced.

Then, the negative pressure in the intake pipe 21 downstream of the intake flow control valve 22 is increased by the throttle effect of the intake flow control valve 22, thereby promoting atomization of the sprayed fuel. Further, even when a part of the spray fuel adheres to the tip of the injector 24, the strong intake air mainstream Im exists at the root side of the injector 24.
No fuel particles move to the root side of No. 4 and the fuel particles of the attached fuel do not grow, and the amount of residual fuel can be reduced.

As a result, it is possible to reduce the amount of the sprayed fuel adhering to the wall surface, to surely guide the sprayed fuel into the combustion chamber 11, and to form a turbulence in the combustion chamber 11 by the intake flow control valve 22. Thereby, it is possible to improve combustion stability and thereby reduce exhaust emissions.

FIG. 2 is a view showing a second embodiment of the intake device for an internal combustion engine according to the present invention. This device differs from the first embodiment shown in FIG. 1 in the arrangement position of the fuel injection nozzle 24n of the injector 24.

As shown in FIG. 2, in this device, the fuel injection nozzle 24n of the injector 24 is disposed at a position C in the main flow Im of the intake air flow. The fuel injection direction is a direction toward the upper position D of the intake port 25, that is, the fuel injection nozzle 24n sprays fuel at a predetermined angle around the straight line CD. The fuel injection direction is originally the intake port 2
Although it is common to move to the center of 5, the present embodiment shows an example of another form.

According to this intake device, the fuel injection nozzle 2
4n is arranged in the main flow Im of the intake flow, and the fuel injection direction is substantially along the main flow Im of the intake flow. Atomization is promoted, and good fuel-intake mixing can be achieved. Then, the fuel is guided to the combustion chamber 211 on the strong airflow,
Fuel adhesion to the wall surface of the intake pipe 21 can be suppressed. In particular, even when a part of the spray fuel adheres to the tip of the injector 24 by spraying the fuel in the main flow Im of the intake air,
Since the attached fuel is carried away by the strong main flow Im of the intake air flow, the fuel particles of the attached fuel do not grow, and the residual fuel amount can be reduced.

As a result, as in the first embodiment, the amount of fuel adhering to the wall surface of the sprayed fuel can be reduced, the sprayed fuel can be reliably guided into the combustion chamber 11, and the combustion is controlled by the intake flow control valve 22. By forming turbulence in the chamber 11, it is possible to improve combustion stability and thereby reduce exhaust emissions.

Here, the injection direction of the fuel in this embodiment does not need to completely coincide with the main flow direction of the fuel. It is enough to make it easy to carry.

In the above description of each embodiment, the case where the intake flow control valve forms the tumble flow in the combustion chamber has been described, but the same holds for the case where the swirl flow is formed.

[0026]

As described above, according to the present invention, the fuel injection nozzle is disposed at a position farther away from the main flow formed by the intake flow control valve, and the fuel is injected in a direction away from the main flow. By doing so, the fuel can be guided in the intended direction without being affected by the main flow, so that the amount of fuel adhering to the intake pipe can be reduced, and a desired combustion improvement effect can be obtained.

Alternatively, according to the present invention, the fuel injection nozzle is arranged in the main flow formed by the intake flow control valve, and the sprayed fuel is easily carried on the main flow.
Good mixing of fuel and air can be achieved, and the amount of fuel adhering to the intake pipe can be reduced, and a desired combustion improving effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of an intake device for an internal combustion engine according to the present invention.

FIG. 2 is a diagram illustrating a second embodiment of an intake device for an internal combustion engine according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder, 11 ... Combustion chamber, 13 ... Intake valve, 21
... intake pipe, 22 ... intake flow control valve, 23 ... actuator, 24 ... injector (fuel injection device), 24n ... fuel injection nozzle, 25 ... intake port.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yuichi Kato 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Tsuyoshi Watanabe 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (4)

[Claims] 1. An intake system for an internal combustion engine comprising an intake flow control valve in an intake pipe and a fuel injection device for injecting fuel downstream of the intake flow control valve, wherein the fuel injection device controls the intake flow control in the intake pipe. An intake device for an internal combustion engine, comprising: a fuel injection nozzle protruding at a position exceeding a main flow of an intake flow formed by a valve. 2. An intake system for an internal combustion engine comprising: an intake flow control valve in an intake pipe; and a fuel injection device for injecting fuel downstream of the intake flow control valve, wherein the fuel injection device controls the intake flow control in the intake pipe. An intake device for an internal combustion engine, comprising a fuel injection nozzle protruding from a main flow of an intake flow formed by a valve. 3. The fuel injection direction of the fuel injection nozzle is:
3. The intake device for an internal combustion engine according to claim 1, wherein the direction is a direction toward a center position of an intake port arranged downstream. 4. The fuel injection direction of the fuel injection nozzle is:
The intake device for an internal combustion engine according to claim 1, wherein the intake device is directed upward.