JPH0345216B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake control method for an internal combustion engine, and particularly to an intake control method for an internal combustion engine having a variable intake swirl type intake port structure.

One of the variable intake swirl type intake port structures used in internal combustion engines has a helical passage that swirls around an opening end to the combustion chamber and a straight passage that linearly communicates with the opening end. An intake port structure in which an intake control valve for opening and closing the straight passage is provided in the middle of the passage was proposed in Japanese Patent Application No. 56-51149 and Japanese Patent Application No. 56-120634 by the same applicant as the present applicant. ing.

In an internal combustion engine equipped with this intake port structure, when the straight passage is closed by the intake control valve, all of the intake air (air mixture) flows through the helical passage and flows into the combustion chamber. A strong intake swirl is generated, which increases the apparent flame speed, making it possible to operate with a lean mixture, and also to ensure stable operation even when the internal combustion engine is operated at low rpm, such as when running at idle. On the other hand, when the straight passage is opened by the intake control valve, the intake air flows through the straight passage in addition to the helical passage and flows into the combustion chamber. By doing so, a strong intake swirl is not generated in the combustion chamber, but the flow resistance of the intake port to the intake air flow is reduced, and a reduction in charging efficiency is avoided.

As described above, when the apparent flame speed increases, the combustion speed increases and the thermal efficiency of the engine improves, but the exhaust gas temperature decreases accordingly. Therefore, even when the engine is cold, if the straight passage is closed by the intake control valve until the intake air amount reaches a predetermined value, high-temperature exhaust gas will not be obtained, and warming up of the engine exhaust system will be delayed. For this reason, in internal combustion engines equipped with a catalytic converter for exhaust gas purification in the engine exhaust system, there is a problem in that the warm-up of the catalytic converter is delayed and the amount of harmful components in the exhaust gas released into the atmosphere increases. .

If the intake control valve is always fully opened when the engine is cold, regardless of the engine load, the exhaust gas temperature will rise and the exhaust system will warm up more quickly, but in this case, originally,
The idling drivability of the engine when the engine is cold becomes even worse, and the idling speed when the engine is cold must be set considerably high.

SUMMARY OF THE INVENTION An object of the present invention is to provide an intake air control method that improves exhaust system warm-up as much as possible without deteriorating idling performance when the engine is cold.

According to the present invention, the present invention has a helical passage that turns around an opening end to the combustion chamber and a straight passage that linearly communicates with the opening end, and the straight passage is provided in the middle of the straight passage. An intake control method for an internal combustion engine having an intake port structure in which an intake control valve that opens and closes is provided, and when the warm-up degree of the internal combustion engine is below a predetermined value, the intake control valve is closed during idling operation. This is achieved by an intake control method characterized in that the intake control valve is always fully opened during other operations, and the opening degree of the intake control valve is controlled in accordance with the amount of intake air when the degree of warm-up is equal to or higher than a predetermined value.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

First, an embodiment of an intake port structure used to carry out the intake control method according to the present invention will be described with reference to FIGS. 1 to 7. In Figures 1 to 7,
Reference numeral 1 designates a cylinder head of an internal combustion engine, which has an intake port 3 for introducing a mixture of air and combustion into a combustion chamber 2. The intake port 3 opens into the side wall of the cylinder head 1 at one end, and opens into the combustion chamber 2 from the bottom wall of the cylinder head 1 at the other end. Here, one end of the intake port 3 is referred to as an inlet opening end 4, and the other end is referred to as an outlet opening end 5. The inlet opening end 4 is connected to an intake manifold (not shown), and the outlet opening end 5 is selectively opened and closed by an annular valve seat member 6 and an intake valve 7 attached to the opening end. There is.

The intake port 3 extends from the inlet opening end 4 to the outlet opening end 5.
as it goes towards the outlet opening end 5,
It is largely bent near the outlet opening end 5 and communicates therewith. A guide vane 10 is formed in a bulging manner on the inner wall of the port (port ceiling wall) facing the outlet opening end 5 . The amount of bulge of this guide vane gradually increases from the inlet opening end 4 toward the outlet opening end 5, and the amount of bulge reaches its maximum at a portion corresponding to the central axis of the outlet opening end 5. ing. A stem 8 of the intake valve 7 passes through this maximum bulging portion, and a valve retainer 9 is attached to this portion. The guide vane 10 has an intake port 3 on one side thereof as it goes from the inlet opening end 4 to the outlet opening end 5 in the extending direction of the intake port 3.
The intake port 3 has an inclined wall portion 11 that is inclined toward the outside, and a straight wall portion 12 that is parallel to the extending direction of the intake port 3 on the other side. This guide vane 1
0, the intake port 3 has a part of its cross section, that is, an upper space region in the figure, defined on one side by an inclined wall part 11 and formed by a helical passage 13 and a straight wall part 12 that turn around the outlet opening end 5. A straight passage 1 defined on one side and leading straight to the outlet opening end 5
It is divided into 4.

An intake control valve assembly 15 is attached to the cylinder head 1. The intake control valve assembly 15 includes a valve case 16 screwed to the cylinder head 1.
, a plate-shaped valve element 17 rotatably supported by the valve case and extending across the middle of the straight passage 14, and a drive lever 19 attached to a valve shaft 18 of the valve element 17. . The valve element 17 fully opens the straight passage 14 when it is in the opening position as shown, and fully opens the straight passage 14 when it is in a position rotated approximately 90 degrees from this opening position.

When the straight passage 14 is in a fully closed state, substantially all of the air-fuel mixture flows through the helical passage 13 and is drawn into the combustion chamber 2 through the outlet opening end 5, creating a strong intake swirl in the combustion chamber 2. occurs. At this time, the flame propagates on the intake swirl, increasing the apparent flame speed and increasing the combustion speed.

When the valve element 17 is opened and the straight passage 14 is open, a part of the air-fuel mixture flows through the straight passage 14 and flows into the combustion chamber 2 from the outlet opening end 5, depending on the degree of opening. As a result, the helical flow of the air-fuel mixture flowing through the helical passage 13 is reduced and attenuated, and the intake swirl generated in the combustion chamber 2 is accordingly reduced, and at the same time, the flow resistance of the intake port 3 to the intake air flow is reduced. descend.

The method of the present invention relates to controlling the opening and closing of the valve element 17, and one embodiment of the apparatus used to carry out the method of the present invention is shown in FIG.

In Fig. 8, 40 is the intake manifold, 41 is the carburetor, 42 is the throttle valve, 43 is the bench lily, 44 is the exhaust port, 45 is the exhaust valve, and 46 is the exhaust manifold. are shown respectively.

A drive lever 19 of the intake control valve assembly 15 is drivingly connected to a rod 21 of the diaphragm device 20;
It is designed to be rotationally driven by the diaphragm device. The diaphragm device 20 has a diaphragm 22, and when a negative pressure of a predetermined value or more is not introduced into the diaphragm chamber 23, the diaphragm 22 is urged downward by the spring force of the compression coil spring 24, thereby closing the valve. When the element 17 is brought to the fully open position as shown, on the other hand, when negative pressure is introduced into the diaphragm chamber 23, the diaphragm 22 resists the spring force of the compression coil spring 24 depending on the magnitude of the negative pressure. By moving the valve element 17 upward, the valve element 17 is driven in the valve opening direction, its opening degree is decreased, and when the negative pressure is equal to or higher than a predetermined value, the valve element 17 is brought to the fully open position. Port 25 of diaphragm chamber 23 is connected to port a of temperature-sensitive switching valve 27 via conduit 26 .

The temperature-sensitive switching valve 27 has two ports b and c in addition to port a, and when the temperature of the cooling water of the internal combustion engine is below a predetermined value, the valve element 28 is in the position shown in the figure and the port a is closed. When the cooling water temperature is above a predetermined value, the thermowax 29 expands and the valve element 28 rises against the spring force of the spring 30, replacing port a with port c. b. Port b is conduit 31, check valve 3
2. It is connected to an intake pipe negative pressure takeout port 34 provided in the intake manifold 40 via a conduit 33, and port c is connected to an intake pipe negative pressure takeout port 36 provided in the carburetor 41 via a conduit 35. There is.

The intake pipe negative pressure outlet port 36 is located downstream of the throttle valve 42 when it is at the idle opening position as shown, and when the throttle valve 42 is at a position opened from the idle opening position. It is now located upstream of that.

The conduit 31 is connected to an atmosphere release valve 50 by a conduit 37 in the middle thereof. The atmosphere release valve 50 closes the port 53 by the valve element 52 when a negative pressure of a predetermined value or more is not introduced into the diaphragm chamber 51. When the valve is in use, the valve element 52 is pulled away from the port 53 to open the valve, and the conduit 37 is opened to the atmosphere through the atmospheric port 54. The port 55 of the diaphragm chamber 51 is connected via a conduit 56 to a vent lily negative pressure outlet port 38 opened at the throat of the vent lily 43 of the carburetor 41 . In the illustrated embodiment, the carburetor 41 is of a single-barrel type, but in the case of a general double-barrel type, the vent lily negative pressure outlet port 38 is connected to either the primary vent lily, the secondary vent lily, or It's good to have openings on both sides.

When the cooling water temperature of the internal combustion engine is below a predetermined value, that is, when the engine is cold, port a of the temperature-sensitive switching valve 27 is connected to port c, so that the diaphragm chamber 23 has an intake pipe negative pressure outlet port 36. A pressure appearing at is introduced. As a result, when the internal combustion engine is in idle operation, a negative pressure equal to or higher than the predetermined value is introduced into the diaphragm chamber 23 from the port 36,
At other times, atmospheric pressure is introduced into the diaphragm chamber 23. Therefore, when the internal combustion engine is idling, the valve element 17 is brought into the fully closed position, and all of the air-fuel mixture flows into the combustion chamber 2 through the helical passage 13, creating a strong intake swirl in the combustion chamber 2. occurs, the apparent flame velocity increases, and the combustion velocity increases. This improves the combustibility of the air-fuel mixture and improves idling performance when the engine is cold. On the other hand, when the engine is operating in an operating state other than idling, the valve element 17 is brought to the fully open position, and the air-fuel mixture flows into the helical passage 1.
3 and the straight passage into the combustion chamber 2, and no strong intake swirl is generated within the combustion chamber 2. As a result, the combustion speed is
Compared to when a strong intake swirl is occurring in the internal combustion engine, the internal combustion engine exhausts hotter exhaust gas than when the combustion speed is high, and the catalytic converter installed in the exhaust system warm-up is promoted.

When the engine cooling water temperature reaches a predetermined value or higher, that is, when the engine has been warmed up, port a of the temperature-sensitive switching valve 27 is connected to port b instead of port c.
When the amount of intake air of the engine is below a predetermined value, a large vent lily negative pressure is not generated in the vent lily negative pressure take-out port 38, so the atmosphere release valve 50 is closed, and therefore, the diaphragm chamber 23 has no intake pipe negative pressure taken out. Intake pipe negative pressure appearing at port 34 is introduced,
This is held by the check valve 32.
As a result, when the internal combustion engine is in idle operation, low to medium load operation, low to medium speed operation and the intake air amount is below a predetermined value, a negative pressure of a predetermined value or more is introduced into the diaphragm chamber 23. Therefore, when the internal combustion engine is operated at a low to medium intake air amount, the valve element 17 is in the fully open and closed position that closes the straight passage 14. At this time, all of the air-fuel mixture flows into the combustion chamber 2 through the helical passage 13, creating a strong intake swirl within the combustion chamber 2, which increases the apparent flame speed and increases the combustion speed. It gets faster. As a result, the combustibility of the air-fuel mixture is improved, and the internal combustion engine performs a good combustion operation without causing a misfire even when the idle speed is low or even when a lean air-fuel mixture is supplied. When the amount of intake air increases due to an increase in the load or rotational speed of the internal combustion engine, and the negative pressure in the vent lily increases accordingly, and reaches a predetermined value or more, the atmosphere release valve 50 opens. At this time, atmospheric pressure is introduced into the diaphragm chamber 23 from the atmospheric port 54, so that the valve element 17 opens, and the air-fuel mixture flows through both the helical passage 13 and the straight passage 14 and flows into the combustion chamber 2. This prevents the intake port 3 from providing a large flow resistance to the flow of the air-fuel mixture, thereby avoiding a decrease in the charging efficiency of the internal combustion engine.

FIG. 9 shows another embodiment of the apparatus used to carry out the method of the invention. In FIG. 9, parts corresponding to those in FIG. 8 are indicated by the same reference numerals as in FIG. In such embodiments, port 25 of diaphragm chamber 23 is connected to conduit 3.
1, and is directly connected to the intake pipe negative pressure outlet port 34, and the conduit 31 is connected to the conduit 39 in the middle thereof.
It is connected to port 61 of temperature-sensitive on-off valve 60 through. The temperature sensitive valve 60 includes a bimetal 62 and a valve element 6
It is a bimetal type including 3, and is sensitive to the cooling water temperature, and when the cooling water temperature is below a predetermined value, ports 61 and 64 are connected, whereas when the cooling water temperature is above a predetermined value, the ports 61 and 64 are connected. It is designed to cut off communication between and 64. Port 64 is connected to intake pipe negative pressure outlet port 36 via conduit 35 . In such an embodiment, when the temperature of the cooling water of the internal combustion engine is below a predetermined value, the temperature-sensitive on-off valve 6 is activated.
0, the diaphragm chamber 23 is connected to the intake pipe negative pressure outlet port 36, so that when the internal combustion engine is running at idle, the diaphragm chamber 2
3, a negative closing of a predetermined value or more is introduced from the port 36, and at other times, atmospheric pressure is introduced into the diaphragm chamber 23. Therefore, also in this example,
When the engine is cold, the valve element 17 is brought to the fully open position during idle operation, and the valve element 17 is brought to the fully open position during non-idle operation.

When the cooling water temperature is above a predetermined value, the temperature-sensitive on-off valve 6 opens and the diaphragm chamber 23 is separated from the port 36, so that the diaphragm chamber 23 receives intake air while the atmospheric release valve 50 is open. The intake pipe negative pressure appearing at the pipe negative pressure outlet port 34 is introduced. Therefore, upon completion of warm-up, the intake control valve 17 remains closed until the amount of intake air reaches a predetermined value or more.

FIG. 10 shows yet another embodiment of the apparatus used for carrying out the method of the present invention. Furthermore, the first
0, the parts corresponding to those in FIG. 8 are designated by the same reference numerals as in FIG. 8.

In this embodiment, port 25 of diaphragm chamber 23 is connected by conduit 26 to port a of electromagnetic switching valve 65. The electromagnetic switching valve 65 has ports b and c in addition to port a, and port b is connected to the intake pipe negative pressure extraction port 34 via the conduit 31, check valve 32, and conduit 33, and port c is connected to the intake pipe negative pressure extraction port 34. open to the atmosphere.

Energization to the electromagnetic switching valve 65 is controlled by a control device 70. Control device 70
In this case, the water temperature switch 71 is opened and closed in response to the cooling water temperature of the internal combustion engine, and the vehicle speed detected by the vehicle speed sensor 72 is determined. The electromagnetic switching valve 65 is activated only when the vehicle speed is below a predetermined value close to zero, that is, when the engine is running at idle.
The electromagnetic switching valve 27 is operated at other times.

When the cooling water temperature of the internal combustion engine is below a predetermined value, that is, when the engine is cold, the electromagnetic switching valve 65 is energized when the internal combustion engine is in idle operation, but when the internal combustion engine is in operation other than idle operation. When the motor is operated in this state, power supply to the electromagnetic switching valve 65 is stopped. Therefore, if the internal combustion engine is running at idle at this time, the diaphragm chamber 23
Negative pressure is introduced from the intake pipe negative pressure outlet port 34, thereby bringing the valve element 17 to the fully closed position. On the other hand, when the internal combustion engine is not in idle operation, the diaphragm chamber 23 is connected to port c of the electromagnetic switching valve 65, thereby introducing atmospheric pressure into the diaphragm chamber, thereby bringing the valve element 17 to the fully open position. .

When the cooling water temperature of the internal combustion engine exceeds a predetermined value,
The diaphragm chamber 23 is always connected to port b of the electromagnetic switching valve 65. Therefore, at this time, until the amount of intake air exceeds a predetermined value, the atmospheric release valve 50 is closed, so that intake pipe negative pressure is introduced into the diaphragm chamber 23 through the intake pipe negative pressure take-out port 34. When the intake control valve 17 is brought to the closed position and the intake air amount exceeds a predetermined value and the atmosphere release valve 50 is opened, atmospheric pressure is introduced into the diaphragm chamber 23 from the atmosphere port 54. The intake control valve 17 is brought to the fully open position. Therefore, in this embodiment as well, the same effects as in the above-mentioned embodiment can be obtained.

Note that the means for detecting that the internal combustion engine is idling is not limited to the vehicle speed sensor, but may be any suitable means such as a throttle opening sensor.

Although the present invention has been described in detail with respect to specific embodiments above, it will be understood by those skilled in the art that the present invention is not limited thereto, and that various embodiments are possible within the scope of the present invention. It should be obvious.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of an intake port structure to which the intake control method according to the present invention is applied;
Figures 2 to 7 are lines from Figure 1 to V, respectively.
-V sectional views and FIGS. 8 to 10 are schematic configuration diagrams showing an embodiment of an apparatus used to carry out the intake control method according to the present invention. 1... Cylinder head, 2... Combustion chamber, 3...
Intake port, 4... Inlet opening end, 5... Outlet opening end, 6... Valve seat member, 7... Intake valve, 8... Valve stem, 9... Valve retainer, 10... Guide vane, 11... ... Sloped wall portion, 12 ... Straight wall portion, 13
...Helical passage, 14...Straight passage, 1
5... Intake control valve assembly, 16... Valve case, 1
7... Valve element, 18... Valve stem, 19... Drive lever, 20... Diaphragm device, 21... Rod, 22... Diaphragm, 23... Diaphragm chamber, 24... Compression coil spring, 25... Port, 26... Conduit, 27... Temperature-sensitive switching valve, 28...
... Valve element, 29 ... Thermowax, 30 ... Spring, 31 ... Conduit, 32 ... Check valve, 33 ... Conduit, 34 ... Intake pipe negative pressure extraction port, 35 ... ... Conduit, 36 ... Intake Pipe negative pressure extraction port, 37... Conduit, 38... Bench lily negative pressure extraction port, 39...
... Conduit, 40 ... Intake manifold, 41 ... Carburizer, 42 ... Throttle valve, 43 ... Bench lily section, 44 ... Exhaust port, 45 ... Exhaust valve, 46 ... Exhaust manifold, 50 ... Atmosphere Opening valve, 51...Diaphragm chamber, 52...Valve element, 53...Port, 54...Atmospheric port, 55
... Port, 56 ... Conduit, 60 ... Temperature-sensitive shut-off valve, 61 ... Port, 62 ... Bimetal, 63
... Valve element, 64 ... Port, 70 ... Control device, 71 ... Water temperature switch, 72 ... Vehicle speed sensor.

Claims (1)

[Claims] 1. It has a helical passage that turns around an opening end to the combustion chamber and a straight passage that leads linearly to the opening end, and an intake control valve that opens and closes the straight passage is provided in the middle of the straight passage. In this intake control method for an internal combustion engine having an intake port structure, when the degree of warm-up of the internal combustion engine is below a predetermined value, the intake control valve is closed during idling operation, and is always fully opened during operations other than idling operation to warm up the engine. 1. An intake control method characterized in that the opening degree of an intake control valve is controlled in accordance with an intake air amount when the intake air amount is equal to or higher than a predetermined value.