JPS6114410A - Engine with forced on-off valve driving gear - Google Patents

Abstract

PURPOSE:To make a favorable high engine speed attainable as well as to improve combustion efficiency in time of a low engine speed, by varying a lift value in a combined suction-and-exhaust valve, being forcedly opened or closed, according to the engine speed. CONSTITUTION:A swing arm 8 is provided with a frame body at its one side, while an arm shaft 17 at the other end is supported by one side 19a of a bell crank 19. Inside the frame body 7, there are provided with a valve opening cam 13 and a valve closing cam 14, and a suction of exhaust valve 1 being connected to the frame body 7 through a long hole 9 of the frame body 7 is forcedly opened or closed. With the bell crank 19 turned round according to an engine speed, a lever ratio (l1+l2)/l2 varies to some extent whereby a lift value of the valve 1 is controlled. At a low engine speed range, an opening area is made smaller and thereby a drop in a velocity of flow in suction and exhaust systems is checkable, thus combustion efficiency at the low engine speed range is improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine equipped with a forced valve drive called Busmodrominok 1 drive.

In conventional engine valves and drive systems, the well is normally closed by a valve spring and opened by a rotating cam. The valve spring serves to seal the valve seat when the valve is closed, and to press the moving parts of the valve train toward the cam when the valve is opened, causing the entire system to move as determined by the cam. Therefore, when the valve is open, a compressive force is exerted by the valve spring between the various parts of the valve train, but if this force disappears for some reason, the valve will float away from the cam. This causes a large shock and noise when they come into contact again. This is called valve jabbing. The fact that the re-O valve flies up due to the impact when the depressed valve is seated is called "balance sink", and it also causes a lot of noise.
When the valve opens and closes, 1υ1 goes out of order, causing Ennon to go into trouble.

In addition, the vibration of the first valve spring caused by the harmonic vibration that occurs when the valve is lifted is called jig, and it not only generates noise, but also causes noise. j1′!
There are times when the spring becomes fatigued and eventually breaks.

This valve spring in the conventional valve train is
It has an important effect on the characteristics of the system and, in turn, the characteristics of the engine, especially at high speeds such as in a racing car.
・In engines that are rotated, valve springs are often unable to follow the high speed rotation of the engine. For this reason, a Tesmotrominok 1 drive device, ie a forced valve drive device, was developed in which the valve is forcibly opened and closed using a cam.

A conventional forced valve drive device is disclosed in US Pat. No. 28142, for example.
Although it is disclosed in the specification No. 88 and the specification No. 34.8061.4, most of them are valve opening cams, valve closing cams,
It constitutes a closed motion transmission system consisting of a cam driven joint such as a rocker arm or a bell crank and a linkage of the valve stem. The problem with engines equipped with such devices is that they are designed for high-speed operation, so the entire engine is designed based on that concept, and the shapes of the intake bow and bleed boat are designed to handle large flow velocities. is designed to obtain. Therefore, during low-speed operation, the flow velocity is small and the combustion efficiency is poor.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an improved engine with a forced valve drive device that allows the flow velocity in the intake and exhaust system to be varied in accordance with the engine speed.

The engine according to the present invention includes a forced valve drive device that forcibly opens and closes both valves using a cam, and means that changes the lift amount of the valve in accordance with the engine speed.

By reducing the valve lift amount set in the high-speed rotation range of the engine in the low-speed rotation range, the valve opening area in the low-speed rotation range is made smaller than the valve opening area in the high-speed rotation range. Thereby, it is possible to suppress a decrease in the flow velocity in the low speed rotation range, and therefore it is possible to improve the combustion efficiency in the low speed rotation range.

Hereinafter, the present invention will be explained with reference to the side drawings.

FIG. 1 is a schematic plan view showing the main parts of an embodiment of the present invention, and FIG. 2 is a schematic front view thereof. The valve 1 is slidably provided in the cylinder head 2 via a guide 5 so that a vent passage 3 such as an intake port or a bleed port provided in the cylinder head 2 can be opened and closed at a valve opening 4 thereof. There is. The tip of the valve stem 6 of the valve 1 is inserted into the elongated hole 9 at the bottom of the swing arm 8 having the frame 7, and then a collar 10 with a spherical lower surface is attached by a stopper ring 11. , is fixed between the ceiling surface 7a and the floor surface 7b of the frame body 7. Between the ceiling surface 7a and the floor surface 7b is a valve opening cam 13 which is integrally fixed to a camshaft 12 which is rotatably driven by a gate 1 held at both ends thereof.
A notch 15 is formed in the ceiling surface 7a corresponding to the locus of the cam ridge of the valve opening cam 13 to escape the cam ridge. A notch 16 is formed in the floor surface 7b corresponding to the locus along which the force L and the peak pass through to escape the force L and the peak. The base of the swing arm 8 is rotatably supported by the arm shaft 17 with its axial movement being regulated.
7 is held at both ends thereof by guide members (not shown) so as to be movable in the left-right direction in the figure.

This arm shaft 17 has a bell crank 1 whose intermediate portion is rotatably attached to the 7-liner head 2 via a shaft 18.
The elongated hole 2 formed in the double piece 19a of the -X section of 9
0 is engaged, and the other end of the bell crank 19 is inserted into the long hole 2 formed there through the pin 22 and the actuating rod 2.
It is connected to 3. The actuating rod 23 is driven in a direction parallel to the arm shaft 17 by an actuator (not shown) that is actuated according to the engine speed and that is actuated by, for example, hydraulic pressure, negative pressure, electromagnetic force, or the like.

Next, the operation of the forced valve drive mechanism of this device will be explained. When the cam shaft 12 is driven and the valve opening cam 13 and the valve closing cam 4 rotate, the swing arm 8 swings up and down around the arm shaft 17, and the frame 7 moves the valve stem 6 up and down. A valve 1 opens and closes a valve opening 4 in a ventilation passage 3. The illustrated state is at the moment when the cam ridge of the valve opening cam 13 is about to push down the floor surface 7b of the frame 7, and at this time the valve closing cam 14 is in contact with the ceiling surface 7a of the frame 7. The cam mountain is about to move to the cam bottom, and the bottom of this cam mountain is on the floor level 7.
It is escaped by a notch 16 formed in b. When the camshaft 12 rotates counterclockwise from this state,
The cam crest of the valve-opening cam 13 presses down the floor surface 7b of the frame 7 to open the valve 1, and then, when the valve 1 begins to return after passing the maximum lift of the valve 1, the cam crest of the valve-closing cam 14 opens. It contacts the ceiling surface 7a of the frame 7 and pushes it up, closes the valve 1 and maintains this state. When the cam crest of the valve-opening cam 13 passes through the ceiling surface 7a of the frame 7, it passes through the notch 15 and does not interfere with the operation of the valve-closing cam 14.

Next, the operation of the variable valve opening area mechanism of this device will be explained. 1 When the actuating arm 23 is driven in the direction of the arrow, the bell crank 19 rotates in the clockwise direction around the shaft 18, and the standing piece 1.9a moves the arm shaft 7 to the right. move it. As described above, the arm shaft 17 is held at both ends thereof by guide portions (not shown) so as to be movable in the left and right directions, so that the bell crank 19
The rotation Φh movement is converted into a linear movement in the left and right force direction of the arm axis 7, and the swing arm 8 is pulled and moved in the right direction. At this time, since the positions of the camshaft 12 and the valve stem 6 are fixed, the swing arm 8 and the frame body 7 move to the right. As a result, the center-to-center distance t1 from the valve stem 6 to the camshaft 12 does not change, and the camshaft 12 and the arm shaft 17-
! The center distance ff$12 at is extended, and the lever ratio t, ±t
2/'! -2 becomes smaller, the lift amount of the valve 1 becomes smaller, the valve opening area becomes smaller, the flow rate of gas passing therein increases, and the combustion efficiency improves.

Therefore, by detecting the rotation speed of the ennon and pulling the actuating rod 23 in the direction of the arrow by an actuator (not shown) in the low speed rotation range, the opening area of the valve becomes smaller and the combustion in the low speed rotation range is reduced. Efficiency is improved.

In the above embodiment, it is not necessary that t2 be larger than 11. The actuating rod 23 may be driven continuously by the actuator 1-actor, or may be driven in two stages with a certain number of revolutions of the ennon as the boundary. In the latter case, the actuation rod 23 may be driven manually.It goes without saying that various forced valve drive mechanisms and valve opening area variable mechanisms may be employed to carry out the present invention.

J: Uni, Enon/ according to this invention is a forced valve drive device f? that forcibly opens and closes both valves using cams. 1″ and
Since it is equipped with a means for changing the valve reflux l"t; and "f according to the engine speed, the engine can be rotated at a good high speed, and the combustion efficiency in the low speed rotation range is improved. .

(FF!'I'l' Explanation on Page 11)
FIG. 2 is a schematic plan view, and FIG. 2D is a schematic front view.

1, - [2...Norindahenoto 3 ・Air passage 4
Valve opening [15 kite 6, valve stem 7 frame body 8 spink arm 10 collar 1 stopper ring 12 cuff, middle white 3 ・valve closing cam 14 valve closing cuff] 5.1
6-1a 17 A-1/Shaft 19 Bell crank 2
3 Action o]... Flood 1 Flash 1st page thread @ Inventor Kiyoshi Hatano 0 Inventor Shima 1) Makoto ■ Inventor Konno
Yoshihiro @ Inventor Hirohiko Iwamoto 1 Uzumasa Tatsumi-cho, Ukyo-ku, Kyoto City Mitsubishi Motors Corporation Kyoto Plant

Claims (1)

[Claims] An engine with a forced valve drive device, comprising: a forced valve drive device that forcibly opens and closes both valves using cams; and means for changing the lift amount of the valve according to the engine speed.