JPH0534483B2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a valve train for an internal combustion engine.

(Prior art and its problems) Poppet valves, which are used in the valve train of general internal combustion engines, are currently employed in most internal combustion engines because of their good sealing properties.
However, when poppet valves are used to further improve the performance of internal combustion engines, burnt exhaust valves may appear in the combustion chamber, promoting detonation or pre-ignition, and valve shafts. The presence of the valve stem in the opening causes ventilation resistance and impairs the intake and exhaust efficiency; the presence of the valve stem and valve stem causes the intake and exhaust passage to be curved near the valve, impairing the intake and exhaust efficiency; The reciprocating motion requires a long space in the direction of movement, making the engine larger, and since the valves are opened and closed by reciprocating motion, there are problems such as an impact noise being generated when the valve is seated (when the valve is closed).

Therefore, in order to eliminate the drawbacks of poppet valves, many sleeve valves and rotary valves have been proposed.In particular, rotary valves (sliding valves) such as ball valves, cylindrical valves, conical valves, and disc valves have been researched. ing.

However, in the rotary valve (sliding valve) systems proposed to date, all of them are given continuous rotational motion to avoid reciprocating motion, and even in the event of an explosion, the valve body rotates while receiving the explosive force. Because of the moving structure, it is impossible to reconcile the contradictory conditions of increased friction and incomplete sealing, and due to the structure of the system, the valve body rotates even during intake and exhaust. In order to obtain effective opening time, it is necessary to widen the opening in accordance with the timing, and if the shape of the opening is changed in this way, expansion loss will occur in the intake and exhaust ports. There are problems such as impairing intake and exhaust efficiency, which hinders its practical application.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and by making the valve body of a sliding valve (rotary valve) immobile (stopped) when the valve is opened and immobile (stopped) during an explosion, the valve body of the sliding valve (rotary valve) can be opened. The purpose is to increase the opening area per unit time during valve operation, improve sealing performance during explosion, and reduce friction.

(Summary of the invention) In order to achieve the above object, the present invention includes:
A sliding valve is provided in each of the intake and exhaust passages communicating with the combustion chamber of an internal combustion engine, and has a sliding surface for opening and closing each of these passages. The internal combustion engine is equipped with a valve mechanism that reciprocates in conjunction with the movement of a piston to open and close the valve for a predetermined period, and has an intermittent function that stops the movement of the valve for a predetermined period during each opening and closing period. It provides valve operating devices for engines.

(Embodiment of the Invention) An embodiment of the present invention will be described below in detail based on the accompanying drawings.

FIG. 1 shows a schematic structure of an internal combustion engine to which a valve train according to the present invention is applied. A piston 4 is connected to the crankshaft 2 of the engine 1 via a connecting rod 3, and the upper end surface of the piston 4 and the cylinder head are connected to the crankshaft 2 of the engine 1. 5 (Figs. 2, 3) and the opening ends of the combustion chamber 6 of the intake passage 7 and the exhaust passage 8 that communicate with the upper part of the combustion chamber 6 (Figs. 2 and 3). An intake slide valve 10 and an exhaust slide valve 20 are respectively disposed in the engine 1, and each of these slide valves 10 and 20 is connected to a valve mechanism 30, which will be described later, and which is driven by the crankshaft 2. The suction and exhaust passages 7 and 8 are inclined at a predetermined port angle θ on both sides with respect to the cylinder centerline.

The sliding valves 10 and 20 are, for example, ball valves.
As shown in FIGS. 1 and 2, the valve seats 11, 1
2. Consists of a valve body 13, a seal spring 14, etc. The valve seats 11 and 12 of this sliding valve 10 are each shaped like a disc, and spherical valve seat surfaces 11a and 12a having a predetermined radius of curvature are recessed on each opposing end surface, and an intake passage is provided in the center. Hole 1 with the same diameter as the inner diameter of 7
1b and 12b are bored. Each of these valve seats 11 and 12 is made of, for example, a ceramic member having excellent heat resistance and wear resistance. The valve body 13 has a spherical shape, the radius of which is set to be the same as the radius of curvature of the valve seat surfaces 11a and 12a, and the outer peripheral surface 13a of the valve body 13 is in close contact with each of the valve seat surfaces 11a and 12a. A hole 13b is bored in the valve body 13,
This hole 13 has the same diameter as the intake passage 7, passes through the center of the valve body 13, is curved with a predetermined radius of curvature, and has an arc shape with both ends opening at predetermined locations on the outer peripheral surface 13a. The valve body 13 is also made of a metal member, such as a stainless steel member, which has excellent heat resistance and wear resistance.

The relationship between the outer diameter (diameter) of the valve body 13 and the inner diameter of the hole 13b is set to an optimum value for sealing performance, friction, output performance, etc.

As shown in FIG. 2, the sliding valve 10 has a seal spring 14, a valve seat 11, a valve body 13, and a valve seat 12 disposed in this order within the cylinder head 5 and at the open end of the intake passage 7 on the combustion chamber 6 side. It is fixed by a cover 9 screwed onto the cylinder head 5. In this installed state, the outer circumferential surface 13a of the valve body 13 rotatably comes into sliding contact with the valve seat surfaces 11a, 12a of the valve seats 11, 12 by the spring force of the seal spring 14. When the hole 13b of the valve body 13 is perpendicular to the intake passage 7, the passage 7 is completely closed, and when they are aligned, the passage 7 is completely opened.

The slide valve 20 is constructed in exactly the same manner as the slide valve 10, and is disposed within the cylinder head 5 and at the open end of the exhaust passage 8 on the combustion chamber 6 side.

An intake camshaft 31 and an exhaust camshaft 32 of the valve mechanism 30 are each rotatably supported by the cylinder head 5, and sprockets 33, 34 and cams 35, 36 are fixed to one end of each. A chain 38 is wound between each of these sprockets 33, 34 and a sprocket 37 fixed to the crankshaft 2. The rotating shafts 40 and 41 are each rotatably supported by the cylinder head 5, and substantially L-shaped arms 42 and 43 are fixed to one end of each. The rotating shafts 44 and 45 are rotatably supported by the cylinder head 5, gears 46 and 47 are fixed to one end of each shaft, and valve bodies 13 and 23 of the slide valves 10 and 20 are fixed to the other end of the rotary shafts 44 and 45, respectively. is fixed.

Each one end 42a, 43a of the arms 42, 43 is fan-shaped and has an arc shape, and teeth are carved on the peripheral surface of each end 42a, 43a to form a deformed gear.
6, 47, and the other ends 42b, 43b are engaged with the cams 35, 47 by return springs 48, 49, respectively.
36 cam surfaces. The shafts 44, 45 are fixed to the valve bodies 13, 23, respectively, in a direction perpendicular to the respective holes 13b, 23b.

The cam surface of the cam 35 is formed as shown in FIG.
The cam surfaces 35a of P ₁ to _{P 2} form an arc with a radius r,
The cam surface 35b, which is connected to the cam surface 35a and has a section P ₂ to _{P 3} for a predetermined rotation angle β of the cam shaft 31, is an arc whose radius of curvature changes continuously from radius r to radius R (>r), which will be described later. The camshaft 3 is connected to the cam surface 35b and is located on the opposite side of the cam surface 35a.
The cam surface 35c in the section P ₃ to _{P 4} for a predetermined rotation angle γ of 1 forms an arc with a predetermined radius R (>r) larger than the radius r of the cam surface 35a, and the cam surface 35c
Similarly to the cam surface 35b, the cam surface 35d, which is connected to the cam surface 35b and is located on the opposite side of the cam surface 35b, in the section P ₄ to _{P 1} with respect to the rotation angle β of the cam shaft 31, has a continuous radius of curvature from the radius R to r. It forms an arc that changes. The cam surface of the cam 36 is also formed similarly to the cam surface of the cam 35. these two cams 3
5 and 36 form a predetermined rotational phase angle and rotate each axis 3.
1 and 32.

In addition, by making the intake and exhaust passages 7 and 8 have a port angle θ, the passages (ports) are aligned with the center of the valve body.
can be arranged freely, providing flexibility in layout and allowing for a compact design.

The operation will be explained below.

As shown in FIG. 1, when the crankshaft 2 rotates in the clockwise direction indicated by arrow C, the camshaft 3
1 and 32 also rotate clockwise. In addition, camshaft 3
The tooth ratio between the sprockets 33 and 34 on the crankshaft 2 and the sprocket 37 on the crankshaft 2 is set to 2:1, and each camshaft 31 and 32 makes one revolution for every two revolutions of the crankshaft 2. do. Arm 42
While the other end 42b is in contact with the cam surface 35a of the cam 35, the arm 42 is rotated clockwise to the maximum position as shown in FIG. 5 by the spring force of the return spring 48 and is held at this position. ,
In response, the valve body 13 of the slide valve 10 is stopped in a state in which the intake passage 7 is completely closed, as shown in FIG. That is, the sliding valve 10 is connected to the other end 4 of the arm 42.
During the period P ₁ to _{P 2} in which the cam surface 35 a is in contact with the cam surface 35 a, the air intake passage 7 is stopped with the intake passage 7 fully closed.

When the cam 35 rotates and the other end 42b of the arm 42 passes the end point _P2 of the cam surface 35a and contacts the cam surface 35b, the contact arm 42 moves counterclockwise against the spring force of the return spring 48 ( The arm 42 is rotated in the direction of the arrow CC in FIG.
The shaft 44 is rotated clockwise via a gear 46 that meshes with teeth on one end 42a. The valve body 13 rotates clockwise together with the shaft 44, and the intake passage 7 is gradually opened accordingly. The other end 42 of the arm 42
When b reaches the end point _P3 of the cam surface 35b, the hole 13b of the valve body 13 completely coincides with the intake passage 7, as shown in FIG. 3, and its opening area becomes maximum. As the camshaft 31 rotates, the other end 42b of the arm 42 becomes a point.
The shaft 44 comes into contact with the cam surface 35c from the position _P3 , and as shown in FIG. 6, the rotation of the shaft 44 is stopped and the valve body 13 stops while it is in contact with the cam surface 35c. The valve body 13 is stopped at the valve opening position until the other end 42b of the arm 42 reaches the end point _P4 of the cam surface 35c. That is, the sliding valve 10 is connected to the other end 42 of the arm 42.
The intake passage 7 is stopped with the intake passage 7 fully open during the period P ₃ to _{P 4} in which the portion b contacts the cam surface 35c. As a result, inhalation efficiency is significantly improved.

The other end 42b of the arm 42 is the end point of the cam surface 35c
When it passes _P4 and comes into contact with the cam surface 35d, the cam 3
5, the arm 42 rotates clockwise due to the spring force of the return spring 48, and the shaft 4 rotates.
4 rotates counterclockwise. The valve body 13 is attached to this shaft 4
4 and rotate counterclockwise to gradually close the valve.
As a result, the intake passage 7 is gradually closed. Then, when the other end 42b of the arm 42 reaches the end point _P1 of the cam surface 35d, the valve body is completely closed again as shown in FIG. 2, and the intake passage 7 is completely closed. In this way, during one rotation of the camshaft 31, the arm 42 swings, and accordingly, the valve body 13 is driven intermittently to swing, and the slide valve 10 is controlled to open and close. During a predetermined period of the valve closing period, the valve body 13
movement is stopped and held in the valve open and closed positions.

The slide valve 20 also operates in the same manner as the slide valve 10, and these slide valves 10 and 20 operate out of phase by a predetermined rotation angle of the crankshaft 2. and,
During the intake stroke of the engine, the sliding valve 10 is stopped at the fully open position for a predetermined period, and the sliding valve 20 is in the closed state, and during the engine's explosion stroke, both of these sliding valves 1 are closed.
0 and 20 both stop at the fully closed position, and during the exhaust stroke, the slide valve 10 is in the closed state and the slide valve 20 is stopped at the fully open position for a predetermined section. As a result, the intake and exhaust efficiency of the engine 1 is greatly improved, the friction of the slide valves 10 and 20 during an explosion is reduced, and the sealing performance is improved.

FIG. 7 is a characteristic diagram showing the relationship between the crank angle and the opening area of a sliding valve. Demonstrates the characteristics of a sliding valve that rotates intermittently,
As is clear from these characteristic curves, according to the valve train of the present invention, the exhaust efficiency is approximately doubled.

Figure 8 is a characteristic diagram showing the relationship between the crank angle and the opening area of the poppet valve and slide valve when the passage (port) diameter is the same.The curve shows the characteristics of the poppet valve, and the curve shows the main 3 shows the characteristics of the sliding valve according to the invention. As is clear from these characteristic curves, the valve operating system of the present invention improves the intake and exhaust efficiency approximately twice as much as that of the poppet valve.

Although this embodiment describes the case where a ball valve is used as the sliding valve, the present invention is not limited to this and can of course be applied to other types of valves such as cylindrical valves, conical valves, disc valves, etc. . Further, it is not necessarily necessary to provide the port angle θ in the intake and exhaust passages 7 and 8.

Furthermore, in this embodiment, a chain type method is described in which the sliding valve is driven directly by the rotation of the crankshaft, but the method is not limited to this. An electric drive method such as a motor may also be used.

(Effects of the Invention) As explained above, according to the present invention, a sliding member is provided in each of the intake and exhaust passages communicating with the combustion chamber of an internal combustion engine, and has a sliding surface for opening and closing each of these passages. The valve and each sliding surface of each sliding valve are reciprocated in conjunction with the movement of the piston of the engine to open and close each predetermined period, and the valve is opened and closed only for a predetermined period during each opening and closing period. Since the engine is equipped with a valve operating mechanism that has an intermittent function to stop the valve movement, the opening area when the valve is opened can be increased, thereby improving the intake and exhaust efficiency and improving the engine output. Furthermore, the friction of the valve body is reduced and the sealing performance is improved, and a cam mechanism, which is a general drive system, can be applied as the valve operating mechanism, so reliability and productivity are improved. It has excellent effects such as:

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an internal combustion engine to which the valve train according to the present invention is applied, and FIG. 2 is a sectional view showing the closed state of the sliding valve of the valve train shown in FIG. , FIG. 3 is a sectional view showing the open state of the sliding valve shown in FIG. 2, FIG. 4 is a plan view showing an embodiment of the cam of the valve mechanism shown in FIG. 1, and FIGS. Figure 6 is a diagram showing the relationship between the cam and arm in Figure 4, and Figure 7 is a diagram showing the relationship between the cam and arm in Figure 4.
8 and 8 are characteristic diagrams showing the relationship between the crank angle and the opening area of the sliding valve. DESCRIPTION OF SYMBOLS 1... Engine, 2... Crankshaft, 7... Intake passage, 8... Exhaust passage, 10, 20... Sliding valve, 11,
12, 21, 22... Valve seat, 13, 23... Valve body, 3
0, 50... Valve mechanism, 35, 36... Cam, 42,
43...Arm.

Claims (1)

[Claims] 1 A sliding valve that is arranged separately in each of the intake and exhaust passages that communicate with the combustion chamber of an internal combustion engine and has a sliding surface that opens and closes each of these passages, and a sliding valve that has a sliding surface that opens and closes each of these passages. The valve mechanism is provided with a valve operating mechanism that reciprocates in conjunction with the movement of the piston of the engine to open and close each valve for a predetermined period of time, and has an intermittent function that stops the movement of the valve for a predetermined period during each opening and closing period. A valve train for an internal combustion engine characterized by: