JPS6065226A - Control device of exhaust system in internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent adhesion before its occurrence of an opening and closing valve when it is placed in a closed condition, by providing a stopper means, which restricts a closing position of the opening and closing valve, so as to suppress an edge end of the opening and closing valve from being adapted to the internal wall of a branch path. CONSTITUTION:A movable saucer-shaped member 23 is placed in a position of full line in the drawing because a centrifugal ball 24 acts on the movable saucer-shaped member 23 by small thrust force when an engine is driven in its low and intermediate speed range. A valve opening spring 30, whose resilient tension gives turning force to a lever 34 through a pressing pin 28, opens an opening and closing valve 15 through a turning shaft 35, level 36, rack rod 38 and a pinion 40. The movable saucer-shaped member 23 is placed in a position of chain line in the drawing by the centrifugal ball 24 when the engine is driven in its high speed range, contracting the valve opening springs 30 to close the opening and closing valve 15. A stopper screw 42 is previously adjusted so that the lever 36 may be received to be stopped by a point end of the stopper screw 42 slightly before an edge end of the opening and closing valve 15 is adapted to the internal wall of a branch path 13.

Description

Detailed Description of the Invention The present invention relates to an exhaust system control device for improving and stabilizing the output performance of an internal combustion engine over a wide operating range from low speeds to high speeds. The present invention relates to an exhaust system control device in which a nonce chamber is connected, and a control device is connected to an on-off valve provided in the branch path to open and close the on-off valve in response to a predetermined operating state of the engine.

Conventionally, in such exhaust system control devices, the closing position of the on-off valve was regulated by bringing the edge of the on-off valve into direct contact with the inner wall of the branch passage. However, due to the difference in hardness, the edge of the on-off valve would dig into the inner wall of the branching path, causing the on-off valve to become stuck in its closed position.

SUMMARY OF THE INVENTION Therefore, the present invention provides the exhaust system control device that eliminates the above-mentioned problems by regulating the closing position of the on-off valve before the edge of the on-off valve comes into contact with the inner wall of the branch path. The feature is that the interlocking mechanism connecting the on-off valve and the control device is provided with a stopper means for regulating the closed position of the on-off valve.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, E is a two-stroke internal combustion engine for a motorcycle, and as usual, a crank case 1, a cylinder block 2 and a cylinder The crankcase 1 supports a crankshaft 4, the cylinder block 2 has a piston 5 slidably fitted into its cylinder hole, and the cylinder head 3 has an ignition plug 6 screwed onto it.

The cylinder block 2 is also provided with an intake port, a scavenging port (none of which are shown), and an exhaust port 9, which are opened and closed by raising and lowering the piston 5. An exhaust pipe 1o communicating with the exhaust port 9 is connected to a positioning collar 11. and bolt 1
2 to the cylinder block 2. The exhaust port 9 and the exhaust pipe 10 constitute an exhaust path pe.

A branch passage 13 opening into the interior of the exhaust pipe 10 is provided in the pipe wall in the middle of the exhaust pipe 10, and a resonance chamber 14 is connected to the branch passage 13.

The branch path 13 has a butterfly-type on-off valve 1 that opens and closes it.
5 is provided. A valve shaft 16 of the on-off valve 15 is rotatably supported in a shaft hole 17 of the exhaust pipe 10, and one end thereof projects into the positioning collar 11. A centrifugal governor type control device C is connected to this valve shaft 16 via an interlocking mechanism M.

As shown in FIGS. 1 and 3, the control device C is provided on the rotating shaft 21 of the water pump 2o, which is driven by the crankshaft 4 through gears 18 and 19. A pair of fixed and movable plate-shaped members 22 and 23 with concave surfaces facing each other so as to sandwich the gear 19 from both sides, and a plurality of centrifugal plates disposed between both plate-shaped members 22 and 23 so as to be movable in the radial direction. A ball 24 (only one is shown in the figure) and a movable plate-shaped member 23 that is pivoted 25 on the crankcase 1 and has one end
The bell crank lever 27 is connected to the back side of the bell crank lever 27 via a release bearing 26.
It is comprised of a valve opening spring 30 that connects the C movable end to the other end via a push pin 2B and a movable seat plate 29 to press the movable plate-shaped member 23 toward the fixed plate-shaped member 22. Valve opening spring 30
A fixed seat plate 31 supporting the fixed end of the spring 30 is supported by an adjusting screw 32 screwed onto the crankcase 1 so that the set load of the spring 30 can be adjusted. This adjustment screw 32 is fixed by a lock nut 33.

The interlocking mechanism M includes a push pin 2 on the side opposite to the valve opening spring 30.
8 and the crankcase 1.
and is supported by the cylinder block 2 and has a third lever 3 at one end.
A rotary shaft 35 to which a rotary shaft 4 is fixed, a second lever 36 fixed to the other end of the rotary shaft 35, and a rotary shaft 36 that is slidably supported in a support hole 37 of the cylinder block 2 and has one end attached to the second lever 36. A valve closing spring 39 is compressed into the engaged rack rod 3B and the support hole 3γ and presses the rack rod 3B toward the second lever 36.
and a pinion 40 formed on the outer periphery of the shaft end of the valve shaft 16 protruding into the positioning collar 11 and meshing with the rack of the rack rod 38.

Therefore, the meshing relationship between the rack rod 3B and the pinion 40 is as follows.
The opening/closing valve 15 is set to close when the rack rod 38 moves toward the second lever 36, and opens when the rack rod 38 moves toward the valve closing spring 39. Also, the first and second levers 34, 36
The relationship is that the spring force of the valve opening spring 30 is
It is set to act as a pressing force on the latch rod 38 toward the valve closing spring 39 side through the latching rod 38, and the pressing force is set to be larger than the shim valve closing + f spring 390 set load.

A stopper screw 42 having a second end and facing the back side of <-36 is screwed into the screw plug 41 that closes the end of the support hole 37 on the second lever 36 side so that the stopper screw 42 can be adjusted forward and backward. The screw 42 constitutes the stopper means of the present invention. 4
3 is a lock nut for fixing the strut screw 42.

Next, to explain the operation of this disaster example, when the engine E is in operation, the crankshaft 4 rotates the rotary shaft 21 via the gears 18 and 19, and the centrifugal force causes the centrifugal ball 24 to move into the movable dish-shaped member. 23 is given a thrust in the direction of separating it from the fixed dish-shaped member 22. However, unless the engine E reaches a predetermined high-speed rotation range, the thrust will not reach the valve opening spring 3.
Unable to overcome the set load of 0, the centrifugal ball 24
is held in the inner position shown by the solid line in FIG. therefore,
In the low to medium speed operating range of the engine E, the elastic force of the valve opening spring 30 applies a clockwise rotational force to the lever 34 via the push pin 28 in the clockwise direction as shown in FIG. to the second lever 36 and rotate it clockwise in FIG.
As a result, the rack rod 38 is moved to the left against the elastic force of the valve closing spring 39, and the valve shaft 16 is rotated clockwise in FIG. The valve is opened as shown by the solid line.

When the engine E enters a predetermined high-speed operating range, the thrust applied to the movable dish-shaped member 23 of the centrifugal ball 24 is applied to the valve opening spring 30.
Since the set load is overcome, the movable dish-like member 23 moves to the left as shown by the chain line in FIG. Then, the valve closing spring 39 moves the rack rod 38 to the right as shown by the arrow in FIG. It rotates as shown by the arrow in the figure to close the on-off valve as shown by the chain line in Figure 5.

In this case, the end edge of the on-off valve 15 should be rotated slightly before it comes into contact with the inner wall of the branching passage 13, and the end edge of the opening/closing valve 15 should be rotated slightly before it comes into contact with the inner wall of the branch passage 13. The screw 42 is adjusted to advance or retreat in advance. When the closing position of the on-off valve 15 is regulated in this way, the on-off valve 1
5 does not come into strong contact with the inner wall of the branch passage 13, so there is a difference in hardness between the two, such as when the exhaust pipe 10 forming the branch passage 13 is made of aluminum alloy and the on-off valve 15 is made of steel plate. However, the on-off valve 15 will not bite into the inner wall of the branch passage 13 and cause a stalemate.

When the on-off valve 15 is in the open state, the natural frequency of the resonant is lowered, and the pipe length of the exhaust passage pe is increased.
It can be effectively used to improve charging efficiency in medium-speed operating ranges.

In addition, when the on-off valve 15 is closed, the resonance chamber 14 is closed, so the exhaust path pe returns to its original natural frequency, and the pipe length of the exhaust path pe is reduced compared to when the on-off valve 15 is open. Therefore, the pulsation effect in the exhaust passage pg can be effectively used to improve the charging efficiency in the high-speed operation range of the engine E.

As described above, according to the present invention, the stopper means for regulating the closing position of the on-off valve is provided in the interlocking mechanism that connects the on-off valve of the branch path and the control device, so that the stopper means for regulating the closing position of the on-off valve is provided. By suppressing contact with the inner wall and preventing the on-off valve from sticking in the closed state, materials for the crossroad inner wall and the on-off valve can be freely selected, which is extremely advantageous in manufacturing.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a front view with main parts cut away of an internal combustion engine equipped with the device of the present invention, and FIGS. 2, 3, and 4 are views of FIG. 5 is a cross-sectional view taken along the lines ①-■, mm and IV-IV, and FIG. 5 is a sectional view taken along the line V-v in FIG. 2. C...Control device, E...Internal combustion engine, M...Interlocking mechanism, PE...Exhaust path, 4...Crankshaft, 9...Exhaust port, 10...
Exhaust pipe, 13... Branch path, 14... Resonance chamber, 15... Open/close valve, 16... Valve shaft, 21...
Rotating shaft, 22... Fixed dish-shaped member, 23... Movable dish-shaped member, 24... Centrifugal hole, 26... Release bearing, 27... Bell crank lever, 2B... Push pin, 30... Valve opening spring, 34.36... 1st.
Second lever, 35... Rotating shaft, 38... Rack rod,
39... Valve closing spring, 40... Pinion, 42...
Stopper screw as a stopper means Fig. 2 Fig. 1 r view Fig. 5 Fig. 3

Claims (1)

[Claims] A resonance chamber is provided in the middle of an exhaust passage of an internal combustion engine via a branch passage, and a control device is attached to an on-off valve provided in the branch passage to open and close the on-off valve in response to a predetermined operating state of the engine. In the exhaust system control device for an internal combustion engine, the interlocking mechanism connecting the on-off valve and the control device is provided with a stopper means for regulating the closed position of the on-off valve. Engine exhaust system control device.