JPH0330696B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake port device for an internal combustion engine that combines a specially shaped intake port and an opening/closing valve to change the direction of intake air introduced into a combustion chamber depending on the load. .

It is desirable that the air taken into the combustion chamber of the internal combustion engine has a suitable swirl flow so as to promote mixing with the fuel. This swirling flow is
This is generally achieved by providing directivity to the intake air with a curved intake port. However, when the engine is under low load, the generation of swirling flow promotes mixing with fuel and improves combustion efficiency, but at high loads, when sufficient air intake is required, the curved port shape increases intake resistance. A problem arises in that the effectiveness is reduced. Therefore, in the past, a partition or a separate port has been provided in the intake port, and a valve has been provided there to change the strength of the swirling flow.
However, if the intake port is provided with a partition, a separate port, or even a valve, the structure of the intake port becomes complicated, which is undesirable in terms of operation, manufacturing, and cost.

The present invention was made in view of the above situation, and the intake port is not provided with a partition or the like, but has a special shape, and a valve is provided on the inlet side of the intake port, and by adjusting this valve, the load can be adjusted. The purpose of this invention is to obtain airflow of a suitable amount and shape, thereby facilitating the manufacture of intake ports, reducing costs, and improving performance under high loads.

The structure of the present invention that achieves the above object is that the intake port of an internal combustion engine has a double structure having a straight part at the top and a spiral part surrounding the intake valve at the bottom, and when the intake port is closed on the inlet side of the intake port, the intake port is closed. It is characterized by a valve that closes the upper part of the inlet that can be opened and closed depending on the load of the engine.

Next, an intake port device according to the present invention will be described in detail based on an embodiment shown in the drawings.

Figures 1a, b, and c show the shape of an intake port 1 according to one embodiment. This intake port 1 is
An upper straight part 1a, a lower part a spiral part 1b formed around an intake valve (the position where the intake valve is provided is omitted in the figure), and a straight part 1c connected tangentially to this spiral part 1b. It consists of. In other words, this intake port 1 has a dual structure of a straight port and a helical port.

Examples of the present intake port device in which the intake port 1 and valve of the above structure are combined are shown in FIGS. 2 to 15.

FIGS. 2a and 2b show a valve 3 in the form of a damper which can be opened and closed on the cylinder head 2 at the inlet of the intake port 1, which is pivotally connected to the cylinder head 2 by a shaft 4. The plate-shaped valve 3 is sized to provide a predetermined amount of clearance 5 at the bottom of the intake port and intake passage 1d having a rectangular cross section. The height l of the gap 5 is, for example, about 5 to 15 mm or about 1/6 of the height of the intake passage 1d.

The example shown in FIG. 3 shows that the valve 3 is provided at the terminal end of the intake manifold 6.

4 and 5 also show the opening/closing mechanism of the valve 3, in which a lever 7 is attached to the end of a shaft 4 that is integrated with the valve 3, and this lever 7 is connected to a vacuum motor 8. . When the engine is under low load, the valve 3 is fully closed by applying negative intake pressure to the vacuum motor 8, and when the engine is under high load, the suction negative pressure applied to the vacuum motor 8 is released, and the tension force of the spring 9 fully opens the valve 3. shall be. At this time, it is preferable that the spring force of the spring 9 of the vacuum motor 8 is activated when the intake negative pressure is about -100 mmHg to 200 mmHg.

By fully closing valve 3 during low load,
Intake air introduced into the combustion chamber flows along the lower part of the intake port 1 through the gap 5 at the lower part of the valve 3. Therefore, the spiral portion 1 provided at the bottom of the intake port 1
(b) generates swirling flow, promotes mixing with fuel, improves combustion efficiency, improves fuel efficiency, and stabilizes combustion during lean combustion when EGR is introduced.
Furthermore, when the valve 3 is fully open, it is possible to ensure a volumetric efficiency comparable to that of a conventional straight port, and it is possible to compensate for the drawbacks of a conventional helical port, such as a decrease in full-open output performance due to a decrease in volumetric efficiency.
In addition, when controlling the opening/closing amount of the valve 3 with respect to engine rotation and load, a three-way solenoid 10 is provided between the vacuum motor 8 and the intake manifold 6, as shown in FIG. 6, and the solenoid 10 is controlled by a computer. Make it drive.

In the embodiment shown in FIG. 7, a step motor 11 is connected to a lever 7 connected to a shaft 4 integral with a valve 3.
The valve 3 is opened and closed from fully closed to fully open depending on the amount of protrusion of the step motor 11. The step motor 11 is controlled by a computer 12 based on engine conditions (throttle opening, water temperature, ignition pulses, etc.) so that the air flow is appropriate to the engine requirements. for example,
Valve 3 is fully closed when idling, opened 45 degrees when traveling at 40 kg/h, and fully opened when under full load.

The embodiment shown in FIG.
A spring 13 is attached to a lever 7 that is integrated with the lever 7. The spring 13 maintains the valve 3 in the fully closed position due to the airflow in the intake manifold 6 during idle operation, and closes the intake air in the intake manifold 6 during full load. The spring load is determined so that the valve 3 is fully opened depending on the amount of air. The positions of the valve 3 other than fully closed and fully open are determined by the intake air amount of the engine. Note that a stopper is provided that comes into contact with the lever 7 when the valve 3 is in the fully closed and fully open positions.

In the embodiment shown in FIGS. 9a and 9b, the valve 3 is supported at the inlet portion of the intake port 1 by a shaft 14 installed at the center in the vertical direction.
and move valve 3 from vertical (fully closed) to horizontal (fully open).
It is designed to rotate up to.

In the embodiment shown in FIG. 10, the valve 3 is provided within the intake manifold 6.

11 and 12 show an example of the drive mechanism of the embodiment shown in FIGS. 9a, b or 10, which has a lever 1 at one end of the shaft 14.
5 is attached, and a vacuum motor 8 is connected to the lever 15. When the load of the engine is low, intake negative pressure is applied to the vacuum motor 8 and the lever 15 is pulled to fully close the valve 3. As the load increases, the intake negative pressure is released and the lever 15 is pushed out to close the valve 3.
open, and fully open during high loads.

In the embodiment shown in FIGS. 13a and 13b, the valve 3 is provided to slide vertically into the intake manifold, and its specific configuration is as shown in FIGS. 14a and b. Place the top of 3 in case 1
The diaphragm 17 and the upper surface of the case 16 are connected by a spring 18, and the upper side of the diaphragm 17 is opened to the atmosphere, while the lower side of the diaphragm 17 is connected to the upper part of the intake manifold 6. . Reference numeral 19 denotes a stopper for regulating the lower end of the valve 3. When the load is low, the negative pressure inside the intake manifold 6 increases,
In other words, the negative pressure below the diaphragm 17 increases, the diaphragm 17 is pulled down against the tensile force of the spring 18, the valve 3 closes, and a swirling flow is generated in the combustion chamber. becomes close to atmospheric pressure, and as shown in FIGS. 15a and 15b, the valve 3 is pulled upward by the spring force of the spring 18, and the valve 3 becomes fully open, suppressing the swirling flow.

As explained above in detail based on the examples,
According to the intake port device according to the present invention, the intake port has a double structure consisting of a straight part and a spiral part, and a valve that is opened and closed according to the engine load is provided at the entrance of the intake port, so that the When the valve is fully closed under load, the intake air introduced into the combustion chamber passes through the gap at the bottom of the valve and flows through the lower part of the intake port, creating a swirling flow due to the spiral section at the bottom of the intake port, which improves combustion efficiency. In addition, by fully opening the valve at high loads, it is possible to secure a sufficient amount of air equivalent to that of a conventional straight port, making it possible to compensate for the decrease in performance. In addition, in this intake port device, the shape of the intake port itself is special, and unlike conventional devices, there are no partitions, separate ports, or valves inside the intake port, which simplifies the structure and reduces manufacturing costs. etc. can be achieved.

[Brief explanation of the drawing]

Figures 1a, b, and c are a side view, plan view, and perspective view of an example of the shape of an intake port in an intake port device according to the present invention, and Figures 2a and b are a schematic sectional view and a side view of one embodiment. 3 is a schematic sectional view of another embodiment, FIG. 4 is a side view of another embodiment, FIG. 5 is a schematic side sectional view thereof, and FIG. 6 is a schematic diagram of an example of a valve opening/closing mechanism. Figures 7, 8, 9a, 10
12, 13a, and 14a are schematic cross-sectional views of different embodiments, FIG. 9b is a side view of FIG. 9a, and FIG. 11 is a side view of FIGS. 10, FIG. 13b is a side view of FIG. 13a, FIG. 14b is a side view of FIG. 14a, and FIGS. 15a and b are side views of FIG. 14a, b. FIG. 2 is a cross-sectional view and a side view of the embodiment shown in FIG. 1 when the valve is fully opened. In the drawing, 1 is an intake port, 1a is a straight part, 1b is a spiral part, 1c is a straight part, 2 is a cylinder head, 3 is a valve, 4 is a shaft, 5 is a gap,
6 is an intake manifold, 7 is a lever, 8 is a vacuum motor, 10 is a three-way solenoid, 11 is a step motor, 13 is a spring, and 17 is a diaphragm.

Claims (1)

[Claims] 1 The intake port of an internal combustion engine has a double structure with a straight part at the top and a spiral part surrounding the intake valve at the bottom, and when the intake port is closed on the inlet side, a valve that closes the upper part of the intake port is placed under the engine load. An intake port device characterized by being provided so that it can be opened and closed according to the conditions.