JPH09280066A - Intake air controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure good combustion of air-fuel mixture irrespective of the time when an engine is warm and the time when the engine is cold and prevent an amount of fuel supplied to the engine when the engine is cold from deviating from normal amount of fuel. SOLUTION: A swirl control valve 17 is arranged in an intake air branch pipe 10, and a fuel injection valve 18 is arranged in an upper inner wall face 10a of the intake air branch pipe 10 on the downstream side of the swirl control valve 17. When an engine is warm, an angle position of the swirl control valve 17 is determined to form an air stream which is directed toward the upper inner wall face 10a so that an upper valve body part 17a of the swirl control valve 17 is maintained in a scope T, thereby promoting the turn of injection fuel into minute particles. When the engine is cold, the angle position of the swirl control valve 17 is determined to form an air current which is directed toward a lower inner wall face 10b so that a lower valve body part 17b of the swirl control valve 17 is maintained in a scope B, thereby preventing the adhesion of injection fuel on an inner wall face of an intake air port 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device for an internal combustion engine.

[0002]

2. Description of the Related Art An intake control valve for controlling an intake air amount is arranged in an intake passage, a fuel injection valve is arranged in an intake passage downstream of the intake control valve, and air flowing through the intake control valve is intake controlled. An intake control device for an internal combustion engine is known in which a valve is guided toward an inner wall surface of an intake passage located on the same side as a fuel injection valve with respect to a central axis of the intake passage (see JP-A-7-83062). . In this intake control device,
The air flow is guided by the intake control valve to collide with the fuel injected from the fuel injection valve, so that the injected fuel is atomized as much as possible.

[0003]

However, when the air flow is guided toward the injected fuel as described above, the injected fuel is deflected by the air flow toward the inner wall surface of the intake passage, and as a result, the inside of the intake passage is deviated. May adhere to the wall. In this case, when the engine is warm, the fuel adhering to the inner wall surface of the intake passage is quickly evaporated and separated from the inner wall surface of the intake passage. However, when the engine is cold, the rate of evaporation of the adhered fuel is low, so the adhered fuel does not quickly separate from the inner wall surface of the intake passage, and as a result, the amount of fuel supplied to the engine deviates from the normal amount of fuel. There is a point. Further, the adhered fuel may flow into the combustion chamber after aggregating on the inner wall surface of the intake passage. In this case, it is difficult to satisfactorily burn the fuel in the combustion chamber, so that a large amount of unburned HC is generated in the exhaust passage. There is a problem of being discharged.

[0004]

In order to solve the above problems, according to the present invention, an intake control valve for controlling the intake air amount is arranged in the intake passage, and a fuel is provided in the intake passage downstream of the intake control valve. In an internal combustion engine having an injection valve, the air flowing through the intake control valve is guided by the intake control valve toward the inner wall surface of the intake passage located on the same side as the fuel injection valve with respect to the central axis of the intake passage when the engine is warm. When the engine is cold, the intake control valve opens so that the air flowing through the intake control valve is guided by the intake control valve toward the inner wall surface of the intake passage located on the side opposite to the fuel injection valve with respect to the central axis of the intake passage. It defines the angular position when the valve is opened. That is, when the engine is warm, the air flow guided by the intake control valve is directed to the injected fuel, so that atomization of the injected fuel is promoted by this air flow. When the engine is cold, the air flow guided by the intake control valve is directed to the inner wall surface of the intake passage opposite to the fuel injection valve, so that the amount of fuel adhering to the inner wall surface of the intake passage is reduced.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
1 is a cylinder block, 2 is a piston, 3 is a cylinder head, 4 is a combustion chamber formed between the piston 2 and the cylinder head 3, 5 is an intake port, 6 is an exhaust port, 7 is an intake valve, 8 is an exhaust valve, Reference numerals 9 respectively indicate spark plugs. The intake ports 5 are connected to the surge tank 11 via the corresponding intake branch pipes 10, and the surge tank 11 is connected to the intake duct 1
It is connected to the air flow meter 13 via 2. on the other hand,
The exhaust port 6 is connected to a common exhaust manifold 14.

Inside the intake duct 12, there is arranged a throttle valve 15 whose opening degree increases as the depression amount of the accelerator pedal increases. A swirl control valve 17 driven by an electromagnetic or negative pressure actuator 16 is arranged in each intake branch pipe 10, and a fuel injection valve 18 is arranged in the intake branch pipe 10 downstream of the swirl control valve 17. It In this case, the swirl control valve 1 composed of a butterfly valve
As can be seen from FIG. 3, the valve shaft 17d of No. 7 is substantially the intake branch pipe 1
When the wall surface of the intake branch pipe 10 that is arranged on the central axis line JJ of 0 and is located above the central axis line JJ of the intake branch pipe 10 is referred to as an upper inner wall surface 10a, the fuel injection valve 18 has an upper inner wall surface 10a. It is arranged in the wall surface 10a. The wall surface of the intake branch pipe 10 located on the side opposite to the fuel injection valve 18 with respect to the central axis J-J of the intake branch pipe 10 is referred to as a lower inner wall surface 10b. Also,
The actuator 16 and the fuel injection valve 18 are controlled based on the output signal from the electronic control unit 20.

With particular reference to FIG. 2, the intake port 5 and the exhaust port 6 are respectively a pair of intake ports 5a and 5b.
And a pair of exhaust ports 6a and 6b are provided, and the intake ports 5a and 5b and the exhaust ports 6a and 6b are provided.
Intake valves 7a, 7b and exhaust valves 8a, 8
b is arranged. Valve shaft 17d of swirl control valve 17
2, the valve body portion of the swirl control valve 17 located on the upper inner wall surface 10a side of the intake branch pipe 10 is referred to as an upper valve body portion 17a. As shown in FIG. 2, the upper valve body portion located on the intake port 5a side is shown. The notch 17c is provided in 17a. Therefore, when the swirl control valve 17 is closed, most of the intake air flows through the cutout 17c. In addition, the valve shaft 17 of the swirl control valve 17
The valve body portion of the swirl control valve 17 located on the opposite side of the upper valve body portion 17a with respect to d is referred to as a lower valve body portion 17b.

In the present embodiment, the angular position of the swirl control valve 17 constituting the intake control valve is either a closed position, a fully open position, or an intermediate position between the closed position and the fully open position, depending on the engine operating state, for example. Controlled by In this case, when the swirl control valve 17 is open, the upper valve body portion 17a is within the range T shown in FIG. 3, or the lower valve body portion 17b is within the range B so that the swirl control valve 17 17 angular positions are defined. That is, when the swirl control valve 17 is open, the upper valve body portion 17
The rotational direction of the swirl control valve 17 is determined so that a is located downstream with respect to the valve shaft 17d or the lower valve body portion 17b is located downstream with respect to the valve shaft 17d.

The electronic control unit 20 comprises a digital computer, and a ROM (read only memory) 22, a RAM (random access memory) 23, a CPU (microprocessor) 24, and an input which are mutually connected via a bidirectional bus 21. It has a port 25 and an output port 26. A water temperature sensor 27 that generates an output voltage proportional to the engine cooling water temperature is attached to the cylinder block 1.
The output voltage of the water temperature sensor 27 is input to the input port 25 via the AD converter 28. A pressure sensor 29 that generates an output voltage proportional to the pressure inside the surge tank 11 is attached to the surge tank 11.
Is output to the input port 25 via the AD converter 30. The CPU 24 calculates the intake air amount based on the output of the pressure sensor 29. Also, the input port 25
A crank angle sensor 31 that generates an output pulse each time the crankshaft rotates, for example, 30 degrees is connected to.
The CPU 24 calculates the engine speed based on the output pulse. On the other hand, the output port 26 is connected to the actuator 16 and each fuel injection valve 18 via the corresponding drive circuit 32.

Next, a method of controlling the swirl control valve 17 when the engine is warm will be described. The swirl control valve 17 is closed during engine low load operation. When the swirl control valve 17 is closed, as described above, the intake branch pipe 10
Most of the air flowing inside flows through the notch 17c. Most of this air then flows into the combustion chamber 4 via the intake port 5a, thus forming a spiral swirl S in the combustion chamber 4 (see FIG. 2). When the swirl S is formed in the combustion chamber 4 as described above, the air-fuel mixture can be satisfactorily combusted in the combustion chamber 4, and thus the amount of unburned HC discharged into the exhaust manifold 14 can be reduced. .

When the engine load increases and the engine operates under medium load, the swirl control valve 17 is opened to an intermediate position between the closed position and the fully open position. In this case, swirl control valve 1
The angular position of the swirl control valve 17 is determined so that the upper valve body portion 17a of No. 7 is within the range T shown in FIG. That is, the upper valve body portion 17a of the swirl control valve 17 is located downstream of the valve shaft 17d. As a result, as shown in FIG. 4, most of the air flowing in the intake branch pipe 10 is guided by the swirl control valve 17 and flows through the gap 40a formed between the upper inner wall surface 10a and the upper valve body portion 17a. Then, thus, the airflow A toward the upper inner wall surface 10a is formed. This air flow A then collides with the injected fuel F injected from the fuel injection valve 18, and as a result, atomization of the injected fuel F is promoted. Therefore, the air-fuel mixture can be satisfactorily combusted in the combustion chamber 4, and the amount of unburned HC discharged into the exhaust manifold 14 can be reduced even during the engine medium load operation.

The upper valve body portion 17a of the swirl control valve 17
Is within the range T in FIG. 3, the air flow A guided by the swirl control valve 17 then flows along the upper inner wall surface of the intake port 5 and flows into the combustion chamber 4. As a result, a swirling flow around the axis orthogonal to the cylinder axis, that is, a so-called tumble flow is formed in the combustion chamber 4, so that the air-fuel mixture can be burned more favorably in the combustion chamber 4.

When the engine load is further increased and engine high load operation is performed, the swirl control valve 17 is fully opened to secure a large amount of intake air. By the way, when the swirl control valve 17 is in the intermediate position, when the airflow A flowing through the swirl control valve 17 is guided toward the injected fuel and collides with the injected fuel as described above, as shown in FIG. The injected fuel F ′ may be deflected and adhere to the inner wall surface of the intake port 5. In this case, when the temperature of the inner wall surface of the intake port 5 is high and the engine is warm, the adhered fuel attached to the inner wall surface of the intake port 5 quickly evaporates and separates from the inner wall surface of the intake port 5.

However, when the temperature of the inner wall surface of the intake port 5 is low and the engine is cold, the evaporation speed of the adhered fuel is low, so that the adhered fuel does not quickly separate from the inner wall surface of the intake port 5. As a result, the amount of fuel supplied into the combustion chamber 4 deviates from the regular amount of fuel, which deteriorates the responsiveness during engine transient operation. Further, the adhered fuel may flow into the combustion chamber 4 after condensing on the inner wall surface of the intake port 5, and in this case, it is difficult to satisfactorily burn the fuel in the combustion chamber 4, so that the exhaust manifold 14 is provided. A large amount of unburned HC will be discharged.

Therefore, in the present embodiment, when the swirl control valve 17 should be in the open position when the engine is cold, the lower valve body portion 17b of the swirl control valve 17 is set within the range B shown in FIG. The angular position of the swirl control valve 17 is defined. That is, the lower valve body portion 17b is located downstream of the valve shaft 17d. As a result, as shown in FIG. 6, a large amount of air flowing through the intake branch pipe 10 is guided by the swirl control valve 17 and flows through the gap 40b formed between the lower inner wall surface 10b and the lower valve body portion 17b. Then, thus, the airflow A toward the lower inner wall surface 10b is formed.
Therefore, the injected fuel F is prevented from being deflected by the airflow A and adhering to the inner wall surface of the intake port 5. In this way, the amount of fuel supplied into the combustion chamber 4 is prevented from deviating from the regular amount of fuel, and good combustion of the air-fuel mixture in the combustion chamber 4 is ensured.

In this embodiment, whether the engine is cold or the engine is warm is judged based on the engine cooling water temperature THW. That is, when the engine cooling water temperature THW is lower than a predetermined set temperature T1, for example, 40 degrees, it is determined that the engine is cold, and when it is higher than the set temperature T1, it is determined that the engine is warm. I am trying. It should be noted that whether the engine is cold or the engine is warm is determined based on the temperatures of the intake branch pipe 10 or the wall surface of the intake port 5, engine oil, intake air, fuel, exhaust gas, and the like. Good.

FIG. 7 is a routine for executing the above-described embodiment. This routine is executed by interruption every predetermined set time. Referring to FIG.
First, at step 50, it is judged if the engine cooling water temperature THW detected by the water temperature sensor 27 is higher than the set temperature T1. When THW> T1, that is, when the engine is warm, the routine proceeds to step 51, where the rotation direction of the swirl control valve 17 is selected so that the upper valve body portion 17a of the swirl control valve 17 is within the range T shown in FIG. It Then, it proceeds to step 53. On the other hand, when THW ≦ T1, that is, when the engine is cold, the routine proceeds to step 52, where the rotation direction of the swirl control valve 17 is set so that the lower valve body portion 17b of the swirl control valve 17 is within the range B shown in FIG. To be selected. Then, it proceeds to step 53.

At step 53, it is judged if the engine is under low load operation. When the engine is under low load operation, the routine proceeds to step 54, where the swirl control valve 17 is closed or held at the closed position. Next, the processing cycle ends. When it is determined in step 53 that the engine is not operating under low load, the routine proceeds to step 55, where it is determined whether the engine is operating under medium load. During engine load operation, the routine proceeds to step 56, where the swirl control valve 17
Are placed in or held in the intermediate position. Next, the processing cycle ends.

In step 55, when the engine is not operating under medium load, that is, when the engine is operating under high load, the routine proceeds to step 57, where the swirl control valve 17 is fully opened or is held at the fully opened position. Next, the processing cycle ends. In the embodiment described so far, the throttle valve 15 is provided in the intake duct 4 upstream of the intake control valve, and the intake air amount is also controlled by this throttle valve. However, it is also possible to configure the intake control valve from a so-called independent throttle valve without providing a throttle valve and control the intake air amount of the corresponding cylinder by only the intake control valve. Further, although the intake control valve is composed of a butterfly valve in the embodiments described so far, the intake control valve may be composed of a rotary valve.

[0020]

EFFECT OF THE INVENTION Since the air-fuel mixture can be satisfactorily burned whether the engine is warm or the engine is cold, the amount of unburned HC discharged into the exhaust passage can be reduced and the engine is cold. It is possible to prevent the fuel amount supplied to the engine from deviating from the regular fuel amount.

[Brief description of drawings]

FIG. 1 is an overall view of an internal combustion engine.

FIG. 2 is a partial plan sectional view of an internal combustion engine.

FIG. 3 is a partially enlarged view around a swirl control valve.

FIG. 4 is a partially enlarged view similar to FIG. 3, showing a swirl control valve when the engine is warm.

FIG. 5 is a partially enlarged view similar to FIG. 3, showing an unfavorable example.

FIG. 6 is a partial enlarged view similar to FIG. 3, showing a swirl control valve when the engine is cold.

FIG. 7 is a flowchart for executing control of a swirl control valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine main body 4 ... Combustion chamber 5 ... Intake port 10 ... Intake branch pipe 10a ... Upper inner wall surface 10b ... Lower inner wall surface 17 ... Swirl control valve 17a ... Upper valve body portion 17b ... Lower valve body portion 18 ... Fuel injection valve 27 ... water temperature sensor A ... air flow F ... injected fuel JJ ... intake branch central axis

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02M 69/00 360 F02M 69/00 360C 360B (72) Inventor Hidemi Ohnaka 1 Toyota Town, Toyota City, Aichi Prefecture Street address Toyota Motor Corporation

Claims (1)

[Claims] 1. An internal combustion engine in which an intake control valve for controlling an intake air amount is arranged in an intake passage, and a fuel injection valve is arranged in an intake passage downstream of the intake control valve. The air flowing through the intake control valve is guided toward the inner wall surface of the intake passage located on the same side as the fuel injection valve with respect to the central axis of the intake passage, and when the engine is cold, the air flowing through the intake control valve is the intake air. An intake control device in which an angular position of the intake control valve when the valve is opened is determined so that the control valve guides the intake control valve toward an inner wall surface of the intake passage located on the side opposite to the fuel injection valve with respect to the central axis of the intake passage.