JPS6350528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake control method and apparatus for an internal combustion engine, and more particularly to an intake control method and apparatus 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 swirling around an opening end to the combustion chamber and a straight passage leading straight to the opening end. Like an intake port structure in which an intake control valve is installed in the middle of the straight passage to open and close the straight passage.
The intake port structure is the same as that of the applicant, having an intake control valve, and configured such that intake swirl increases when the intake control valve is closed compared to when the intake control valve is open. This was proposed in Japanese Patent Application No. 56-51149 and Japanese Patent Application No. 120634-1981 by the applicant of .

In an internal combustion engine equipped with the above-mentioned intake port structure, when the straight passage is closed by closing the intake control valve, almost all of the intake air (air mixture) flows through the helical passage and into the combustion chamber. This creates a strong intake air swirl in the combustion chamber, which increases the apparent flame speed, allows operation with a lean mixture, and also allows the internal combustion engine to run at low rpm, such as when running at idle. It provides stable drivability even at low speeds, and allows the idle speed to be set low. On the other hand, when the straight passage is opened by opening the intake control valve, the intake air flows through the straight passage in addition to the helical passage and flows into the combustion chamber, which prevents a strong intake swirl from occurring inside the combustion chamber. The flow resistance of the intake port to the intake air flow is reduced, and a reduction in filling efficiency is avoided.

The above-mentioned intake port structure is used when the internal combustion engine is operated at idle or low load in order to effectively utilize this structure, that is, to improve combustion during idle or low load operation without reducing engine output. When the internal combustion engine is operating at a medium to high load, the intake control valve is opened to open the straight passage. Used in combination.

As mentioned above, when the apparent flame speed increases,
This increases the combustion rate and improves the thermal efficiency of the engine, but
Accordingly, the exhaust gas temperature decreases. For this reason, if the straight passage is closed by the intake control valve during idling or low-load operation even when the engine is cold, high-temperature exhaust gas cannot be obtained, resulting in a delay in warming up the exhaust system of the engine. 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 The present invention aims 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, and a device used to implement the method. It is.

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 3. 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 fuel 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 open end 4 is connected to an intake manifold (not shown), and the outlet open end 5 is connected to an intake manifold (not shown).
is selectively opened and closed by an annular valve seat member 6 and an intake valve 7 attached to the opening end.

The intake port 3 is inclined toward the outlet opening end 5 as it goes from the inlet opening end 4 toward the outlet opening end 5, and is largely bent near the outlet opening end 5 to communicate 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 is
It has an inclined wall part 11 on one side thereof which is inclined toward the outside of the intake port 3 as it goes from the inlet opening end 4 to the outlet opening end 5 in the extending direction of the intake port 3, and the other side has an inclined wall part 11 which is inclined toward the outside of the intake port 3. It has a straight wall portion 12 parallel to the extending direction of the port 3. With this guide vane 10, the intake port 3 has a helical passage 13 whose part of its cross section, that is, the upper space region in the figure, is defined on one side by an inclined wall part 11 and which turns around the outlet opening end 5; It is divided into a straight passage 14 defined on one side by a straight wall part 12 and communicating linearly with the outlet opening end 5.

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. . When the valve element 17 is in the open position (valve closed position) as shown in the figure, the straight passage 14 is fully closed, and when it is in a position rotated approximately 90 degrees from this open position, that is, in the valve open position. The straight passage 14 is fully opened.

When the straight passage 14 is in a fully closed state due to the opening of the valve element 17, substantially all of the air-fuel mixture flows through the helical passage 13 and is sucked into the combustion chamber 2 through the outlet opening end 5. A strong intake swirl occurs within the engine. 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 damped, 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. decreases.

The method and apparatus of the present invention relate 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, 44 is the exhaust port, 45 is the exhaust valve, and 46 is the exhaust valve.
indicate the exhaust manifolds.

The drive lever 19 of the intake control valve assembly 15 is drivingly connected to a rod 21 of a diaphragm device 20 and is adapted 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 moved by the spring force of the compression coil spring 24.
The valve element 17 is forced downward as shown in the figure.
is brought to the fully open position, and on the other hand, when negative pressure is introduced into the diaphragm chamber 23, the diaphragm 22 moves upward against the spring force of the compression coil spring 24 according to the magnitude of the negative pressure. The valve element 17 is driven in the valve closing direction to reduce its opening degree, and when the negative pressure is greater than a predetermined value, the valve element 1
7 to the fully closed position as shown. Port 25 of diaphragm chamber 23
is connected to port a of the temperature-sensitive switching valve 27 via a 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. is connected to port c, and 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, thereby replacing port a with port c. It is designed to connect to port b. Port b is connected to a first intake pipe negative pressure outlet port 32 provided in an intake manifold 40 via a conduit 31, and port c is connected to a first intake pipe negative pressure outlet port 32 provided in an intake manifold 40 through a conduit 31.
It is connected to a second intake pipe negative pressure extraction port 34 provided in the carburetor 41 through the.

The first intake pipe negative pressure outlet port 32 is always located downstream of the throttle valve 42. The second intake pipe negative pressure outlet port 34 is connected to the throttle valve 4
When the throttle valve 2 is in the idle opening position as shown in the figure, it is located downstream of it, and when the throttle valve 42 is in a position opened from the idle opening position, it is located upstream of it. There is.

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 a second intake pipe negative pressure is created in the diaphragm chamber 23. Removal port 34
A pressure appearing at is introduced. As a result, when the internal combustion engine is idling, a negative pressure equal to or higher than the predetermined value is introduced into the diaphragm chamber 23, and 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 to the fully closed position as shown, and substantially all of the air-fuel mixture flows through the helical passage 1.
3 into the combustion chamber 2, a strong intake swirl is generated in the combustion chamber 2, the apparent flame speed increases, and the combustion speed increases. This improves the combustibility of the air-fuel mixture and improves the 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 through both the helical passage 13 and the straight passage 14 into the combustion chamber 2. The air flows into the combustion chamber 2, and a strong intake swirl does not occur within the combustion chamber 2. As a result, the combustion speed becomes slower than when a strong intake swirl is generated in the combustion chamber 2, and the internal combustion engine begins to discharge hotter exhaust gas compared to when the combustion speed is high. The warm-up of the catalytic converter, etc. installed in the catalytic converter 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, and the diaphragm chamber 23 receives the first intake air. The pressure appearing at the tube negative pressure outlet port 32 is now introduced. As a result, when the internal combustion engine is operating at idle or at low load, a negative pressure equal to or higher than the predetermined value is introduced into the diaphragm chamber 23, and as the load increases, the negative pressure introduced into the diaphragm chamber 23 increases. Decrease.

Therefore, when the internal combustion engine is operating at idle or at low load, the valve element 17 is in the fully closed position, closing the straight passage 14, as shown. At this time, almost 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. Become. 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 at a low idle speed or when a lean air-fuel mixture is supplied. When the load on the internal combustion engine increases and the intake pipe negative pressure decreases to a predetermined value or less, the valve element 17 opens. At this time,
The mixture is helical passage 13 and straight passage 14
By flowing through both of the air-fuel mixtures and into the combustion chamber 2, the intake port 3 no longer presents 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 2.
6 and is connected to port a of the electromagnetic switching valve 35. The electromagnetic switching valve 35 has port b in addition to port a.
and port c, and port b is connected to the conduit 31
The port c is connected to a first intake pipe negative pressure outlet port 32 via a conduit 33, and the port c is connected to a second intake pipe negative pressure outlet port 34 via a conduit 33. The electromagnetic switching valve 35 connects port a to port c when the coil 36 is energized, and connects port a to port b instead of port c when the coil 36 is not energized. It's summery. Current from a battery power source 37 is selectively supplied to the coil 36 via an ignition switch 38 and a water temperature switch 39. The water temperature switch 39 is sensitive to the temperature of the cooling water of the internal combustion engine, and closes only when the temperature is below a predetermined value.

Therefore, in this embodiment as well, when the engine is cold, the pressure appearing at the second intake pipe negative pressure outlet port 34 is introduced into the diaphragm chamber 23, and after the engine is warmed up, the pressure appearing at the first intake pipe is introduced into the diaphragm chamber 23. The pressure present at the negative pressure outlet port 32 is introduced.

As a result, the same effects as those of the above-mentioned embodiment can be obtained in this embodiment as well.

Although the present invention has been described above in detail with reference to specific embodiments, it is understood that the present invention is not limited to these and that various embodiments are possible within the scope of the present invention. This will be obvious to businesses.

[Brief explanation of the drawing]

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 the lines of Figure 1, respectively.
8 and 9 are schematic configuration diagrams showing embodiments of the 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 shaft, 19... Drive lever, 20... Diaphragm device (hydraulic actuator), 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 ...
...first intake pipe negative pressure outlet port, 33... conduit,
34...Second intake pipe negative pressure extraction port, 35...
Solenoid switching valve, 36... Coil, 37... Battery power supply, 38... Ignition switch, 39...
...Water temperature switch, 40...Intake manifold, 4
1... Carburetor, 42... Throttle valve, 44
...Exhaust port, 45...Exhaust valve, 46...Exhaust manifold.

Claims (1)

[Scope of Claims] 1. An intake port having an intake control valve and configured such that when the intake control valve is closed, intake swirl increases compared to when the intake control valve is open. In the intake control method for an internal combustion engine having a structure, when the warm-up degree 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, so that the warm-up degree is maintained at a predetermined value. An intake control method characterized by closing the intake control valve during idling or low load operation when the value exceeds the engine load value, and increasing the valve opening amount in response to an increase in engine load during medium to high load operation. 2. An internal combustion engine having an intake port structure having an intake control valve and having an intake port structure configured such that intake swirl increases when the intake control valve is closed compared to when the intake control valve is open. The intake control device includes a fluid pressure actuator that has a fluid pressure working chamber and drives the intake control valve in a valve closing direction in response to an increase in negative pressure acting on the fluid pressure working chamber, and a fluid pressure actuator that is always downstream of a throttle valve. The first intake pipe negative pressure outlet port is located on the side, and when the throttle valve is in the idle opening position, it is located downstream of it, and when the throttle valve is in a position opened from the idle opening position, it is located downstream of it. A second intake pipe negative pressure takeout port located upstream of the internal combustion engine is connected to the second intake pipe negative pressure takeout port, and when the warm-up degree of the internal combustion engine is below a predetermined value, the fluid pressure working chamber is connected to the second intake pipe negative pressure takeout port to warm up the engine. and a switching valve that connects the fluid pressure working chamber to the first intake pipe negative pressure outlet port when the pressure is above a predetermined value.