JPS6146647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of an internal combustion engine having a plurality of intake valves per combustion chamber, and more specifically, the present invention relates to the structure of an internal combustion engine having a plurality of intake valves per combustion chamber, and more specifically, the present invention relates to the structure of an internal combustion engine having a plurality of intake valves per combustion chamber. This invention relates to a multi-intake valve type internal combustion engine that can be easily modified.

Internal combustion engines with several intake valves per combustion chamber are known. However, in such a known dual intake valve type internal combustion engine, at least one of the plurality of intake valves is
The settings of the two opening/closing control conditions cannot be changed arbitrarily, and the structure is complicated and reliability is poor.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a dual-intake valve internal combustion engine that allows for arbitrary changes in opening/closing control conditions, has a simple structure, and is highly reliable.
The object of the present invention is to control a rocker arm that opens and closes at least one of the two intake valves in an internal combustion engine having two intake valves per combustion chamber. Two cams having different cam profiles are movable relative to the axial direction of a camshaft which is fixed adjacent to each other through a force storage mechanism using elastic bias, and between the two different cams. A double intake valve type, which is provided with a rocker arm stopper that extends from the base portion to the lag side when viewed in the rotational direction of the cam, and is capable of adjusting the operating condition of the at least one intake valve according to the operating condition of the engine. Achieved by internal combustion engine.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view schematically showing one cylinder of an internal combustion engine according to the present invention, and the internal combustion engine according to the present invention has a plurality of such cylinders. cylinder block 1
A cylinder bore 1a is bored in the cylinder bore 1a.
The piston 5 is slidably and sealingly fitted therein. A cylinder head 3 having a combustion chamber wall 3a (shown in FIG. 6, but not shown in FIG. A combustion chamber 7 is formed which is surrounded by a surface. A combustion chamber 7 and a combustible mixture adjusting device (not shown) such as a carburetor are connected to a main intake system 12 consisting of a main intake boat 8 and a main intake valve 10, and a sub-intake system 14 consisting of a sub-intake port 9 and a sub-intake valve 11. communicate by. The main intake port 8 and the sub-intake port 9 diverge from each other at appropriate locations. The combustion chamber 7 is also communicated with an exhaust pipe (not shown) through an exhaust valve 16 and an exhaust port 18.
The burnt gas inside will be exhausted. Further, an ignition plug 20 connected to a high voltage power source (not shown) is connected to the combustion chamber 7.
Attach to.

In the embodiment shown in FIG. 1, the main intake port 8 communicating with the main intake valve 10 is formed as a helical port in the form of a screw. This improves combustibility by forming a swirl.

The structure of the main intake valve and the main intake port is not limited to that of the first embodiment. For example, as shown in FIG. Any suitable structure can be used, such as the structure shown in FIGS. The main intake valve 110 shown in FIG. 3 has a screw-shaped vane 110b installed on the back surface of the valve body 110a, and the main intake valve 210 shown in FIG. A shroud 210b is provided protrudingly. Therefore, the combustible air-fuel mixture taken in from the main intake port 108 flows through the valve body 110a or 210 of the main intake valve 110 or 210.
Vane 110b or shroud 21 on the back side of a
0b to form a swirl. The main intake valve 310 shown in FIG. 5 has a valve seat 311 on which it is seated.
The valve body 3 of the main intake valve 310 is attached to the outer combustion chamber wall 3a.
It is accompanied by a protrusion (mask) 311a that protrudes so as to partially surround the periphery of 10a. Therefore, when the main intake valve 310 is opened as shown by the chain line, the valve body 310a and the protrusion 311a come close to each other, increasing the flow resistance, and the combustible air-fuel mixture from the main intake port 108 passes through the protrusion (mask). The fuel is ejected into the combustion chamber 7 in a predetermined direction as shown by the chain arrow A from the portion that is not provided, thereby forming a swirl.

The main intake valve 10, 110, 210 or 310 is controlled to open and close in time with the engine crankshaft (not shown) with a constant valve lift.

On the other hand, the opening and closing conditions of the auxiliary intake valve 11 are variable as will be described later, depending on the operating state of the engine. The intake port 9 connected to the auxiliary intake valve 11 may be a helical port as shown in FIG. 1, or may be linear as shown in FIG. 2 so that the intake air-fuel mixture can be sucked in with small intake resistance. Further, the sub-intake valve shown in FIG. 1 and the sub-intake valve shown in FIG. 2 may be replaced as appropriate.

The opening/closing mechanism of the sub-intake valve 11 according to the embodiment of the present invention will be described in detail below with reference to FIGS. 6 to 8. First, referring to Figure 6, the main intake valve, exhaust valve, exhaust port, and spark plug are omitted in this figure, and the same parts as in Figure 1 are given the same reference numerals. The explanation will be omitted.
The auxiliary intake valve 11 includes a valve body 11a that controls the intake of intake air in cooperation with a valve seat 9a formed at the opening of the auxiliary intake boat 9 to the combustion chamber 7, and a cylindrical valve protruding from the valve body 11a. It consists of rod 11b. valve rod 1
1b is slidably and sealingly fitted into the cylinder head 3, and a retainer 13 is fixed to the rear end of the valve rod 11b which projects above the cylinder head 3. A compression spring 15 is installed between the retainer 13 and the upper surface of the cylinder head 3 to urge the sub-intake valve 11 upward and seat the valve body 11a on the valve seat 9a. A cylindrical valve lifter 17 is fitted into the upper end of the valve rod 11b of the auxiliary intake valve 11 so that it can slide within the recess 3b formed in the cylinder head 3. By pressing the upper surface of the valve lifter 17 downward, the auxiliary intake valve 11
It is possible to open the valve.

The rocker arm 19 is made slidable around the rocker shaft 21. Tip 19 of Rotzker arm 19
Screw the stopper 25 onto the lock nut 23 so that its length can be adjusted, and attach the pad 19b at the other end to the cam 2.
7. The cam 27 is provided on a cam shaft 29 parallel to the rocker shaft 21 as shown in FIG. 7, and includes two adjacent cams 27a and 27b. The cam profiles of the two cams 27a, 27b differ in valve lift and/or valve timing. For example, the cam 27a is a cam profile for low engine speeds or a circular arc cam equal to the radius of the base circle, and the cam 27b is a cam profile for high engine speeds. The base circles of both cams 27a and 27b substantially coincide with each other, and both cams rotate in the direction of arrow a in FIG. 6 together with the camshaft 29, which rotates in time with the engine crankshaft (not shown). .

The rocker arm can be moved in the axial direction of the camshaft 29 by, for example, the following moving mechanism. A rocker arm 19 is fitted to the outside of a rocker shaft 21 formed of a hollow cylinder so as to be swingable and movable, and a rocker arm moving shaft 23 extending in the axial direction is inserted into the hollow part of the rocker shaft 21 in a loosely fitted state. A linear movement mechanism is connected to the left end 23a of the rocker arm movement shaft 23 in FIG. As the linear movement mechanism, in addition to the hydraulic cylinder 24 shown in FIG. 7, a known structure such as a pneumatic cylinder, a motor mechanism with a rack and pinion (not shown), etc. can be used. Two annular stoppers 31 and 33 are fixed to the rocker arm moving shaft 23 with an interval between them, and
Two annular movable stoppers 35 and 37 are connected between the two annular stoppers 31 and 33 on the rocker arm moving shaft 23.
The adjacent stopper 31 is movably fitted loosely into the
and 35, and compression connection springs 39 and 41 between 33 and 37.
Attach. As shown in FIG. 8, an elongated hole 21a in the axial direction is bored in the rocker shaft 21, and the tip of a bolt 43 screwed onto the rocker arm 19 is passed through the elongated hole 21a, and is positioned between the stoppers 35 and 37. , 37. A cam 27a on the outer periphery of the Rocker shaft 21,
Two annular grooves 21b, 21 corresponding to the 27b position
c so that the positioning ball 45 in the small hole 19e formed in the rocker arm 19 is urged by the bolt 49 and the spring 47 to engage.

Main intake valves 10, 11 shown in FIG. 1 or 2
0, 210, or 310 is also controlled to open and close by a valve mechanism consisting of a rocker arm and a cam (not shown), and in this embodiment, the rocker arm for the main intake valve can be swung at a fixed position on the rocker shaft 21. one cam (not shown) on the camshaft 29 corresponding to the rocker arm;
is fixed.

With the above configuration, the main intake valves 10, 110, 21
0 or 310 is always opened and closed under constant opening and closing conditions. On the other hand, the sub-intake valve 11 is connected to the hydraulic cylinder 2.
4, the opening/closing operation is performed under different opening/closing conditions. That is, when the hydraulic cylinder 24 is actuated, movement energy is accumulated in the compression springs 39 and 41, and when the accumulated energy exceeds the biasing force of the ball 45 and spring 47, the rocker arm 19 is instantaneously moved. During this movement, the cams 27a, 27b due to the difference in cam profile of both cams 27a, 27b.
or the adjacent cam 27 to prevent wear and damage of the rocker arm 19 and maintain smooth engine operation.
The following mechanism is provided to perform this while the pad 19b at the tip of the rocker arm 19 is in contact with the base circle portions a and 27b.

The cam shaft 29 located between the cams 27a and 27b is connected to two points 29a and 29 separated by a distance t as shown in FIG.
The compression spring 61 has a flat outer shape surrounded by an arc of radius R centered at b, and a small hole 29c is bored from the lower outer surface in the direction connecting both centers 29a and 29b.
and wear-resistant small balls 63 are attached. In addition, small hole 2
As is clear from FIG. 6, 9c is located on the lag side from the base circle portion when viewed in the rotational direction (arrow a) of the cam 27. The ring-shaped rocker arm stopper 55 has an inner periphery with a radius equal to or slightly larger than the radius of curvature R of the camshaft 29, and the compression spring 6
1 and a small ball 63, the arrow H is
When the cam 27 is pressed in the direction, it protrudes from the cam surface by a predetermined height (L) between the base circular part and the lift part of the cam 27, and when an external force acts on the rocker arm stopper 55 from the outside to the inside, the spring 61 is pushed. Resisting the pressure, it sinks to the same height as the cam surface. By appropriately selecting the spring 61, the pressing force can be easily set to a desired value, and the flat shape of the camshaft 29 and the circular annular shape of the rocker arm stopper 55 ensure that the protruding position of the rocker arm stopper is maintained. Corresponds to the biasing member position. The locker arm stopper 55 is made up of two arcuate bodies 55a and 55b, and the engagement surfaces thereof are shaped like male and female keys, and the tips of the engagement surfaces are chamfered. A notch is formed, and when both arcuate bodies 55a, 55b are pressed in the radial direction using the chamfered part as a guide, they engage with each other to form a rocker arm stopper 55.

With the above-mentioned Locker arm stopper 55, the Locker arm 19 is stopped when the Locker arm 19 is switched.
When the pad 19b is in contact with the base circles of the cams 27a and 27b, the switching is performed without any problem, and even if the pad 19b is placed on the rocker arm stopper 55 during switching, the pressing force of the pad 19b will cause the lock to be locked. The car arm stopper 55 sinks and rotates around the rocker shaft 29, allowing smooth switching without causing any impact. On the other hand, the rocker arm 19 is positioned at the protruding portion of the rocker arm stopper 55 from the cam surface during switching. If so, movement of the rocker arm 19 will be blocked and switching will not take place until the next base circle is reached.

Note that the structure of the Rocker arm stopper is not limited to the above-mentioned structure, and for example, a leaf spring may be extended in an arc shape from the base circular portion to the lag side when viewed in the rotational direction of the cam between two adjacent cams. .

Further, the rocker arm moving mechanism is not limited to the above-mentioned mechanism, and for example, a rocker arm moving mechanism may be provided outside of the rocker shaft in parallel with it.

The number of intake valves provided in one combustion chamber is not limited to two, but may be three or more as appropriate.

Although in the illustrated embodiment of the invention the rocker arm is moved relative to the camshaft, the invention may also be adapted to have the rocker arm rock in a fixed position while the camshaft is moved axially relative to the rocker arm. .

According to the present invention, by activating or stopping at least one of the plurality of intake valves depending on the engine operating conditions, the total opening area of the intake valves is changed to respond to engine load conditions, rotation speed, and other operating conditions. In addition, by appropriately changing the cam profiles of a plurality of intake valves that operate simultaneously, the valve timing can be changed depending on the operating situation. Moreover, with the configuration of the embodiment, it is possible to generate high suction turbulence during low-speed operation depending on the driving situation to improve combustibility, while achieving a high intake air amount during high-speed operation. Thus, high output and good fuel economy can be achieved.

In addition, in the present invention, as a relative movement mechanism between the rocker arm and the cam, a force storage mechanism using elastic bias is adopted, so this mechanism is connected to the rocker arm stopper provided between the two cams. This prevents the rocker arm and the cam from being worn out or damaged during relative movement between the rocker arm and the cam, and allows smooth and instantaneous movement.

[Brief explanation of the drawing]

1 and 2 are respectively perspective views showing one cylinder of an internal combustion engine according to the present invention, FIG. 3 is a front view of the main intake valve of the engine shown in FIG. 2, and FIG. 4 is a front view of the main intake valve of the engine shown in FIG. FIG. 5 is a front sectional view of another main intake valve, FIG. 6 is a front sectional view of the opening/closing mechanism of the auxiliary intake valve shown in FIG. 1 or 2, and FIG. 7 is a front sectional view of another main intake valve. −
The arrow view, FIG. 8 is the - arrow view of FIG. 1...Cylinder block, 3...Cylinder head, 7...Combustion chamber, 10...Main intake valve, 11,1
10,210,310... Sub-intake valve, 16... Exhaust valve, 19... Rocker arm, 21... Rocker shaft, 23... Rocker arm movement axis, 27,2
7a, 27b...cam, 29...camshaft, 55...
…Lotskar arm stoptupa.

Claims (1)

[Scope of Claims] 1. In an internal combustion engine having two intake valves per combustion chamber, a rocker arm that opens and closes at least one of the two intake valves is controlled to open and close the at least one intake valve. Two cams having different cam profiles are movable in the axial direction of the camshaft fixed adjacently through a force storage mechanism using elastic bias, and between the two different cams. is provided with a rocker arm stopper extending from the base circle toward the lag side when viewed in the rotational direction of the cam, so that the operating condition of the at least one intake valve can be adjusted in accordance with the operating condition of the engine. Features a dual intake valve type internal combustion engine. 2. A member that forms the rocker arm stopper into a circular annular shape with a larger diameter than the camshaft outer diameter, fits the camshaft, and urges the stopper outward to a position on the lag side with respect to the base circular portion of the camshaft. 2. The dual intake valve type internal combustion engine according to claim 1, wherein the outer periphery of the stopper protrudes downwardly from the cam surface at the position. 3. Claim 1, wherein the two intake valves form a flow of intake air while forming a swirl when a combustible air-fuel mixture is taken in, and a flow of intake air that is drawn in linearly with small intake resistance. The dual intake valve type internal combustion engine described in .