JPH0442527B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an intake port of an internal combustion engine used in a vehicle such as an automobile, and particularly to a variable swirl type intake port.

Prior art and its problems In internal combustion engines, combustion efficiency is improved by improving the mixing properties of fuel and air in the combustion chamber, and by increasing the flame speed of the mixture of fuel and air in the combustion chamber. In order to improve this, various intake ports, such as a helical type, have been proposed in the past, which are configured to guide intake air into the combustion chamber so that the intake air moves in a swirling manner within the combustion chamber.

The swirling motion of the intake air generated in the combustion chamber by flowing into the combustion chamber from the intake port as described above is a swirling motion around the axis of the cylinder bore, and this swirling motion is called an intake swirl, and increases the amount of intake air. The intensity increases as the intake air flow rate through the intake port increases.

If the intake port is configured so that sufficient intake swirl can be obtained during low-speed, low-load operation when the amount of intake air is small and the flow rate of intake air passing through the intake port is relatively low, the amount of intake air will be large. During high-speed, high-load operation where the flow rate of intake air passing through the intake port is relatively high, the intake swirl becomes too strong, resulting in the so-called over-swirl phenomenon. In spark-ignition internal combustion engines, this over-swirl phenomenon causes the spark from the spark plug to blow out, and in direct-injection diesel engines, it weakens the penetration force of the fuel injection amount from the fuel injection nozzle. This causes a reduction in the effective utilization rate of intake air in the combustion chamber, and has an adverse effect on combustibility and exhaust gas performance.

In addition, helical-type intake ports, which are configured to generate sufficient intake swirl during low-speed, low-load operation, often have a large flow resistance to the intake air, which reduces the charging efficiency of internal combustion engines. become.

In view of the above-mentioned phenomenon, the patent application proposes an intake port in which a movable intake flow guide member is provided in the intake port, and the degree of occurrence of intake swirl can be variably controlled by the intake flow guide member. 1977-
No. 62577 (Special Publication No. 51-7243), Patent Application No. 1972-94819
(Special Publication No. 51-38370), Japanese Patent Application No. 89438 (Sho. 47-12845), Japanese Patent Application No. 27703 (Sho. 51-112010), Japanese Patent Application No. 65785 (Sho. 51) (Unexamined Japanese Patent Publication 1973)
-148714) etc., various proposals have already been made.

However, in the previously proposed variable swirl type intake ports as described above, it is not possible to change the passage shape and passage cross-sectional area of the spiral passage portion, which have a large effect on the generation of intake swirl. Therefore, in these cases, it is not possible to variably control the strength of the intake swirl over a wide range.On the other hand, in recent years, especially with the increase in output and high speed operation of automobile internal combustion engines, intake swirl There is a growing demand for an increase in the variable width of

Purpose of the Invention An object of the present invention is to provide an improved intake port for an internal combustion engine that has a wider variable range of swirl strength than conventional intake ports, has a simple structure, and performs reliable variable swirl control. There is.

According to the present invention, it is an object of the present invention to provide a linear passage section that extends substantially linearly in the upstream portion of the intake port, and a straight passage portion that extends in a substantially straight line in the upstream portion of the intake port, and a straight passage portion that extends in a substantially straight line in the upstream portion of the intake port, and a portion that extends around the valve shaft of the intake valve in the downstream portion of the intake port. In an intake port of an internal combustion engine having a curved passage portion extending in a curved manner and terminating in an open end opening into a cylinder bore, one end is engaged with a convexly curved inner circumferential wall of the curved passage portion. Extends along one side wall of the straight passage portion connected to the convex inner circumferential wall to the other end located at the inlet of the intake port via an elongated portion extending linearly with respect to the convex inner circumferential wall. an intake flow guide member made of an elastic plate, and as the other end of the intake flow guide member is moved toward the downstream side of the intake port along the one side wall of the straight passage portion, The curved passage portion is configured to project from the convexly curved inner circumferential wall toward the concavely curved outer circumferential wall, and to limit the effective passage cross section in the curved passage portion to a portion along the concave outer circumferential wall. This is accomplished by the intake port of an internal combustion engine.

Effects of the Invention According to this configuration, when the other end of the intake flow guide member is moved toward the downstream side of the intake port along the one side wall of the straight passage portion,
The intake sulfur guide member protrudes from the convexly curved inner circumferential wall toward the concavely curved outer circumferential wall in the curved passage portion, and the effective passage cross section in the curved passage portion is largely curved along the outer circumferential portion. The intake passage has a small extending cross-sectional area, and even in the case of a low-flow intake flow, a large swirl is given to the intake flow to cause it to flow into the combustion chamber, and an intake port structure suitable for low-load operation can be obtained.

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

1 to 3 show one embodiment of an intake port for an internal combustion engine according to the invention. In the figure, 1 indicates a cylinder head, and an intake port 2 is provided in the cylinder head.

The intake port 2 is a so-called helical intake port, and has a substantially rectangular cross section that extends along an imaginary plane substantially perpendicular to the axis of the cylinder bore 50, that is, a horizontal plane in the figure, and has an intake inlet 3 at one end. A straight straight passage section 4, and a curved passage section 6 having a circular cross section, which extends pivoting around the valve shaft 5 of the intake valve, connects to the straight passage section 4 at one end, and opens into the cylinder bore 50 at the other end. It has Curved passage section 6
is a so-called spiral passage, and has a cylindrical peripheral wall 8 extending eccentrically around the valve shaft 5, and a cylinder bore 50.
The opening end, that is, the intake outlet 7, is formed in a circular shape concentric with the valve shaft 5, and the intake outlet has an annular valve seat member (not shown) on which the intake valve is selectively seated.
is installed. The curved passage portion 6 is provided with a valve shaft support portion 9 having an annular cross section that supports the valve shaft 5 of the intake valve.

An intake flow guide member 10 is provided on the outer periphery of the valve shaft support portion 9.
is locked. The intake flow guide member 10 has an extension portion 12 that extends from a locking end 11 to the valve shaft support portion 9 in an extended line shape to the outer circumferential surface of the valve shaft support portion 9.
and an arcuate portion 1 extending in an arcuate manner continuously from the extending end of the extending portion 12 along one side wall of the first passage portion 4.
3 and is made of a relatively thin elastic thin metal plate having spring properties.

The arcuate portion 13 of the intake flow guide member 10 is close to the upper wall of the straight passage section 4 at its upper edge with a very small gap, and is close to the lower wall of the straight passage section 4 at its lower edge with a very small gap. They are close to each other with a small gap between them. A pin 14 protruding from the upper edge and lower line is fixed to the distal end of the arcuate portion 13, and the pin 14 is connected to guide grooves provided in the upper and lower walls of the curved passage portion 4, respectively, at both ends thereof. 15 in a movable manner.
A guide groove 15 is provided on one side of the straight passage portion 4 along its extending direction, and the intake flow guide member 10 is guided by the guide groove as shown by the solid line in FIGS. 1 and 2. between a first position in an undeformed state, as shown in FIG. It is starting to move to .

When the intake flow guide member 10 is in the first position, the cross-sectional area of the intake passage gradually decreases from the intake inlet 3 side toward the intake outlet 7 due to the expansion portion 12 of the intake flow guide member 10, thereby increasing the intake flow. On the other hand, a helical intake passage that provides a throttling effect is formed.
Therefore, at this time, the intake air flowing into the straight passage portion 4 from the intake inlet 3 first passes through the intake air flow guide member 10.
is guided by the arcuate portion 13 and the side wall of the straight passage portion 4, and flows toward one side of the valve stem support portion 9 of the curved passage portion 6 while increasing the flow velocity due to the throttling effect.
Further, the air flows into the cylinder bore 50 from the air intake outlet 7 while swirling around the valve shaft support part 9 while further increasing the flow velocity while being guided by the expansion part 12 of the air intake flow guide member 10 and the peripheral wall 8 . This allows cylinder bore 5
A relatively strong intake swirl occurs within 0.

When the other end of the intake flow guide member 10 is pulled and moves from the first position to the second position, the intake flow guide member 10 is elastically deformed, and the extension portion 12 is aligned with the valve shaft. By approaching the outer peripheral surface of the guide portion 9 so as to wrap around it, the passage cross-sectional area of the curved passage portion 6 is expanded. Due to this enlargement of the passage cross-sectional area, the effect of increasing the intake air flow velocity is reduced, and the intake swirl generated within the cylinder bore 50 is accordingly weakened.

When the intake flow guide member 10 is located at the second position, the expansion line portion 12 wraps around the outer peripheral surface of the valve shaft guide portion 9, thereby maximizing the cross-sectional area of the curved passage, and reducing the intake air generated within the cylinder bore 50. Swirl is at its weakest.

3 and 4 show one embodiment of a drive device for driving an intake port intake flow guide member according to the invention between the first position and the second position. In FIGS. 3 and 4, parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals as in FIGS. 1 and 2.

In this embodiment, pin 14 of each intake port
A cap member 16 is attached to the upper end of the cap member 16, which acts as a cam follower. Cylinder head 1
The camshaft 18 is inserted into the hole 17 extending in the cylinder arrangement direction.
is inserted to be rotatable about its axis, and a cam 19 that engages with the cap 16 is attached to the camshaft for each intake port. A drive lever 20 is attached to one end of the camshaft 18.
The drive lever is drivingly connected by a rod 21 to an actuator, such as a diaphragm device, and is adapted to be driven clockwise as viewed in FIG. 4, for example, in response to an increase in the amount of intake air of the internal combustion engine.

As the drive lever 20 rotates in the clockwise direction as seen in FIG. This is pulled and driven from the first position towards the second position.

5 and 6 show another embodiment of the drive device according to the invention for driving the intake flow guide plate of the intake port between a first position and a second position. In FIGS. 5 and 6, parts corresponding to those in FIGS. 1 and 2 are designated by the same reference numerals as in FIGS. 1 and 2. In such an embodiment, a drum cam 2 is attached to the cylinder head 1.
2 is provided rotatably around its own central axis for each intake port, and the upper end of the pin 14 engages with a cam groove 23 provided on the outer peripheral surface of the drum cam so as to be inclined in the circumferential direction. are doing. drum cam 2
2 has a camshaft 24 integrally provided on an extension of its central axis, the camshaft protrudes outside the cylinder head 1 at one end, and has a drive lever 25 at the end. There is. The drive lever 25 is pivotally connected to a control rod 26 extending along the cylinder arrangement direction of the cylinder head 21, and rotates as the control rod 26 moves up and down as seen in FIG. 22 to rotate around its own central axis. The drum cam 22 is rotationally driven around its central axis, and selectively pulls the intake flow guide plate 10 to the right as seen in FIG. It is adapted to be driven between the first position and the second position.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited to the above-mentioned embodiments, and various other embodiments are possible within the scope of the present invention. This will be obvious to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a plan sectional view showing one embodiment of the intake port of an internal combustion engine according to the present invention, FIG. 2 is a perspective view showing the intake port shown in FIG. 1, and FIG.
FIG. 4 is a cross-sectional view taken along the line IV--IV in FIG. 3; 5 is a plan sectional view showing another embodiment of the drive device for the intake flow guide member of the intake port according to the present invention shown in FIGS. 1 and 2, and FIG. 6 is a cross-sectional view taken along the line shown in FIG. It is a sectional view along VI-VI. 1...Cylinder head, 2...Intake port, 3
...Intake inlet, 4...First passage part, 4...Valve stem of intake valve, 6...Second passage part, 7...Intake outlet, 8...Peripheral wall, 9...Valve stem guide part , 10...
Intake flow guide member, 11... Engaging portion, 12... Extension portion, 13... Arched portion, 14... Pin, 15... Guide groove, 16... Cap, 17... Hole, 18...
Control rod, 19...cam, 20...drive lever, 21...rod, 22...drum cam, 23
...Cam groove, 24...Cam groove, 25...Drive lever, 26...Control rod.

Claims (1)

[Claims] 1. A straight passage section that extends substantially straight in the upstream part of the intake port, and an open end that extends curved around the valve axis of the intake valve and opens into the cylinder bore in the downstream part of the intake port. In an intake port of an internal combustion engine having a curved passage portion terminating in the curved passage portion, one end is locked to a convexly curved inner circumferential wall of the curved passage portion, and the intake port extends in an expanding line from the convex inner circumferential wall to the convex inner circumferential wall. an intake flow guide member made of an elastic plate that extends along one side wall of the straight passage portion that is connected to the convex inner circumferential wall through an extension portion that extends to the other end located at the entrance portion of the intake port; As the other end of the intake flow guide member is moved toward the downstream side of the intake port along the one side wall of the straight passage portion, the intake flow guide member moves closer to the convexly curved inner circumferential wall of the curved passage portion. An intake port for an internal combustion engine that projects toward a concavely curved outer circumferential wall and is configured to limit an effective passage cross section in the curved passage portion to a part along the concave outer circumferential wall.