JPS62206223A - Exhaust controller for engine - Google Patents

Abstract

PURPOSE:To prevent the biting of valve by arranging a plurality of exhaust pipes in single parallel row with the valves being arranged in respective pipes on a single shaft then arranging a thrust bearing at one end of the shaft and making the exhaust pipes and the valve bodies more eccentric as they depart further from the thrust bearing. CONSTITUTION:Plural exhaust pipes of a multi-cylinder are arranged in parallel into single row and valves 42a-42d for restricting the exhaust gas disposed in the exhaust pipes are arranged on a single shaft. A thrust bearing 44 is arranged at one end of the shaft and a drive pulley 52 is arranged at the other end. The centers A1-A4 of the valves provided on the shaft are arranged against the centers B1-B4 of the exhaust pipes such that the eccentricities l1-l4 are increased as they depart from the thrust bearing 44. Although the shaft expands thermally when the engine is operated, said eccentricity prevents the biting of valve in the exhaust pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an engine exhaust control device in which exhaust control valves are provided in each of a plurality of exhaust pipes extending from an exhaust port of the engine to an expansion chamber.

(Background of the Invention) It is known that in 4-stroke engines, 2-stroke engines, etc., exhaust gas is intermittently guided into the exhaust pipe by opening and closing the exhaust valve, causing an inertial effect and a pulsation effect of the exhaust gas in the exhaust pipe. . These effects (referred to as dynamic effects) vary depending on engine speed. Therefore, if this dynamic effect is maximized to increase the volumetric efficiency at the rotational speed, the dynamic effect acts in the opposite direction at other rotational speeds, resulting in a significant decrease in the volumetric efficiency. Therefore, if the exhaust system specifications (exhaust pipe length, exhaust pipe system, etc.) are set so that this dynamic effect is optimal in the high speed range, the torque will significantly decrease (torque trough) in the medium speed range. There was a problem that occurred.

Therefore, an exhaust control valve that changes the area of the exhaust flow path is installed near the opening end of the exhaust pipe to the expansion chamber, reducing the flow path area in the rotation speed range where volumetric efficiency decreases, and reducing the flow path area in other rotation speed ranges. The idea is to increase the amount.

Furthermore, in a multi-cylinder engine, if the downstream sides of the exhaust pipes are merged in an expansion chamber, this may cause a reduction in volumetric efficiency and a reduction in torque due to exhaust interference between the cylinders. Therefore, it has been considered to provide an exhaust control valve for each exhaust pipe and close this control valve in a rotational speed range where the adverse effects of exhaust interference occur to reduce the exhaust flow path area.

In addition, an exhaust control valve is installed in the middle of the exhaust pipe to improve combustion and self-EGR (exhaust gas recirculation) by controlling back pressure.
It is also being considered to control the exhaust components by controlling the

In this way, it is conceivable to install an exhaust control valve that changes the exhaust flow path area in the exhaust pipe for various purposes such as improving volumetric efficiency, improving combustion, and controlling exhaust components. In this case, each exhaust pipe must be provided with an exhaust control valve, and if each is controlled independently, the problem arises that the control device becomes complicated.

In addition, if the valve stem of each exhaust control valve is made common, the valve stem becomes longer and expands more due to heat, and the valve body provided on the valve stem and the exhaust pipe become more difficult to operate when the engine is hot or cold. The problem of interference also arises.

(Objective of the Invention) The present invention was made in view of the above circumstances, and it is possible to simplify the control device when each exhaust control valve is provided in a plurality of exhaust pipes, and also to prevent the valve stem from expanding or contracting due to heat. An object of the present invention is to provide an engine exhaust control device that can prevent a valve body provided on a valve shaft from interfering with an exhaust pipe.

(Structure of the Invention) According to the invention, this purpose is to provide a plurality of exhaust pipes each having one end connected to an exhaust port of the engine and the other end connected to an expansion chamber;
In an engine including an exhaust control valve provided in each exhaust pipe to change an exhaust flow path area of each exhaust pipe, each exhaust control valve has one valve shaft that crosses each exhaust pipe, and an exhaust control valve that is provided in each exhaust pipe. A plurality of valve bodies correspondingly fixed to the valve stem and one thrust receiver for restricting movement of the valve stem in the axial direction are provided, and the width of the valve body is set to be smaller than the inner diameter of the exhaust pipe. On the other hand, when the engine is in a cold state, the amount of deviation of the center of the valve body from the center of the exhaust pipe in the direction of the thrust receiver is set to increase as the distance from the thrust receiver increases. This is accomplished by a device.

(Function) If the valve shaft is rotated in accordance with the operating state of the engine, the exhaust flow path area of each exhaust pipe changes based on the operating state of the engine.

As the engine temperature rises, the valve stem stretches, and the valve body moves away from the center of the exhaust pipe in the opposite direction of the thrust receiver.

(Example) Fig. 1 is a partially sectional rear view of an exhaust control valve assembly which is an embodiment of the present invention, Fig. 2 is a plan view of the same, and Fig. 3 is an exhaust system of a motorcycle using the same. FIG. 4 is a side view, and FIG. 5 is a side view of a motorcycle using this exhaust system.

In Fig. 4.5, reference numeral 10 is a 4-stroke, 4-cylinder engine, which is mounted near the center of the vehicle body. This engine 10 has a cylinder 14 extending diagonally upward and forward from a crankcase 12. The exhaust system includes a four-wood exhaust pipe 16 extending from the front of the cylinder 14 to the bottom of the crankcase 12.
(16a-16d), an exhaust control valve assembly 18 connected to the rear end of each exhaust pipe 16;
8 and two exhaust pipes 16a connected to the rear surface of the engine.

Two expansion chambers 22 (22a, 22b) are provided for collecting the exhaust gases 16b, 16c, and 16d, respectively, and guiding them to two mufflers 20 (20a, 20b).

In FIG. 5, 24 is a front wheel, 26 is a steering wheel, 28 is a rear wheel, 30 is a cover that covers an intake air cleaner and a fuel tank, and 32 is a driver's seat.

The exhaust control valve assembly 18 integrates a plurality of exhaust control valves 34 (34a to 34d) that change the exhaust passage area of each exhaust pipe 16, and includes a main body 36 fixed to the rear end of the exhaust pipe 16, and a main body 36 fixed to the rear end of the exhaust pipe 16. A circular hole 38 (38a to 38d) arranged in parallel in the horizontal direction so as to communicate with each exhaust pipe 16, one valve shaft 40 passing through each circular hole 38, and a valve body fixed to the valve shaft 40. The valve plate 42 (42a to 42d) is provided.

The right end of the valve shaft 40 is restricted from moving in the axial direction by a thrust receiver 44 . That is, a retaining ring 46 fixed to the right end of the valve stem 40 is connected to the concave chamber 4 provided on the right side of the main body 36.
A thrust receiver 44 is formed by being sandwiched between the bottom surface of the recess 8 and a cover member 50 press-fitted into the recessed chamber 48 .

The valve plate 42 has a circular shape with a smaller diameter than the inside diameter of the exhaust pipe 16, and its center AI"A4 is located near the exhaust pipe 1 when the engine 10 is cold.
The displacement amount 1+-14 is set to increase as the distance from the thrust receiver 44 increases (FIG. 1).

In other words, sentence 1> sentence? 〉Sentence 3〉Sentence 4 is set.

A pulley 52 is fixed to the left end of the valve shaft 40, and the pulley 52 is forcibly rotated in both directions by a servo motor 56 via a wire 54. This servo motor 56 has a control circuit that closes each control valve 34 in a rotation range where volumetric efficiency deteriorates and opens it in other rotation ranges based on the engine rotation speed detected from, for example, an ignition device 958 (see Figure 3). 60.

Therefore, the diameter and length of the exhaust pipe 16 are determined by the engine 10.
When the volumetric efficiency is set to be high in the high speed range, the control circuit 60 drives the servo motor 56 to close the exhaust control valve 34 in the middle speed range. Each exhaust control valve 34 has one
The valve shafts 40 are synchronously controlled to have the same opening degree.

The positive pressure wave caused by the opening of the exhaust valve of the engine 10 propagates in the exhaust pipe 16 at the speed of sound, and the negative pressure wave generated by the rapid expansion at the open end propagates in the opposite direction through the exhaust pipe 16 at the speed of sound. If the exhaust control valve 34 located near this opening end, which returns to the exhaust valve of the engine IO, is closed, the positive pressure wave caused by the opening of the exhaust valve will be reflected by the exhaust control valve 34 and will be reflected as a positive pressure wave. It returns to the exhaust valve at the speed of sound. Therefore, if the exhaust control valve 34 is controlled to reduce the exhaust flow path area to 1/2, a negative pressure wave generated by the open end of the exhaust pipe and returned, and a positive pressure wave reflected by the exhaust control valve 34. The sum of is zero. At this time, the pulsation effect is canceled out,
It is possible to suppress the decrease in volumetric efficiency (occurrence of torque valley) in the medium speed range.

In addition, when this exhaust control valve 34 is used for the purpose of preventing torque reduction due to exhaust interference between cylinders, it is sufficient to close this exhaust control valve 34 in a rotation range where torque reduction due to exhaust interference is significant. When the control valve 34 is closed, an exhaust control valve 34 that reduces the exhaust flow path area by about 90% to about 10% can be used.

When the engine 10 is cold, the valve plate 4
2 is offset toward the thrust receiver 44 side. engine lO
As the engine warms up, the thrust valve shaft 40 extends to the left in FIG. That is, as the distance from the thrust receiver 44 increases, the amount of deviation of the valve shaft 40 increases. As the valve plate 42 becomes farther away from the thrust receiver 44, the exhaust pipe 16 becomes more distant when it is cold.
Since the deviation ml from the center is set large, the valve plate 42 does not interfere with the inner surface of the exhaust pipe 16 when the engine is hot.

In the above embodiment, the exhaust control valve 34 was provided near the opening end of the exhaust pipe 16 to the expansion chamber 22, but it may be provided at other positions of the exhaust pipe 16 depending on the purpose of the exhaust pipe 16, for example, at the back. For pressure control and self-EGR, it is desirable to provide it at a position close to the engine 10, and it may also be located close to the downstream side of the open end of the exhaust pipe 16.

(Effects of the Invention) As described above, the present invention provides one valve shaft so as to cross the exhaust pipe, restricts the axial movement of this valve shaft with one thrust receiver, and The amount of deviation of the exhaust pipe from the center of the exhaust pipe increases as the distance from the thrust receiver increases when the engine is cold.

Therefore, even if the engine temperature rises and the valve stem stretches, interference between the valve body and the exhaust pipe can be prevented. Further, each exhaust control valve can be controlled by a single driving means such as a servo motor, which simplifies the control device.

[Brief explanation of drawings]

FIG. 1 is a partially sectional rear view of an exhaust control valve assembly according to an embodiment of the present invention, FIG. 2 is a plan view of the same, and FIG. 3 is a plan view of an exhaust system of a motorcycle using the same. FIG. 4 is a side view, and FIG. 5 is a side view of a motorcycle using this exhaust system. Ward lO...Engine, 16.
...exhaust pipe, 18...exhaust control valve assembly, branch 22...expansion chamber, 34...exhaust control valve, 40...valve shaft, 42...valve plate as a valve body, 44... Thrust receiver, A... Center of valve plate, B... Center of exhaust pipe, Text... Amount of deviation.

Claims (1)

[Scope of Claims] A plurality of exhaust pipes each having one end connected to an exhaust port of the engine and the other end connected to an expansion chamber, and an exhaust control valve provided in each of the exhaust pipes to change the exhaust flow path area of each exhaust pipe. In the engine, each of the exhaust control valves has a valve shaft that crosses each exhaust pipe, a plurality of valve bodies fixed to the valve shaft corresponding to each exhaust pipe, and a shaft of the valve shaft. The width of the valve body is set to be smaller than the inner diameter of the exhaust pipe, and the width of the valve body is set to be smaller than the inner diameter of the exhaust pipe, and the width of the valve body is set to be smaller than the inner diameter of the exhaust pipe. An exhaust gas control device for an engine, characterized in that the amount of deviation in the thrust receiving direction is set to increase as the distance from the thrust receiving direction increases.