JPS62206224A - Exhaust controller for engine - Google Patents

Abstract

PURPOSE:To increase the freedom for arranging an exhaust pipe and to simplify the driving mechanism by arranging the exhaust pipes of a multi-cylinder engine in parallel for every cylinder while arranging the shafts of valves provided for respective exhaust pipes in parallel and providing a transmission mechanism between respective valve shafts. CONSTITUTION:The exhaust pipes 16a-16d of a multi-cylinder engine are arranged independently for every cylinder and an exhaust valve 18 is provided for every exhaust pipe. The shafts of valves for the exhaust pipes 16a, 16b and 16c, 16d are shifted each other and a transmission mechanism A is provided between both valves. Furthermore, a drive section 46 comprising an actuator 50 which is driven by means of a controller 54 for producing an output corresponding to the rotation 52 is provided at the end of the valve shaft. Since a valve shaft is provided independently for every exhaust pipe, the freedom for arranging the exhaust pipe is increased, while since a single drive section 46 opens/closes all valves, the driving mechanism is simplified.

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 with engine rotation 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.

Furthermore, if the valve stems of the exhaust control valves are made common, a problem arises in that the valve stems elongate due to heat. Furthermore, depending on the location of the exhaust pipes, there may be restrictions on how the exhaust pipes can be arranged, resulting in an inconvenience that the degree of freedom in design when determining the arrangement of the exhaust pipes is reduced.

(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 providing exhaust control valves in each of a plurality of exhaust pipes, and to reduce the elongation of the valve stem due to heat. An object of the present invention is to provide an engine exhaust control device that can increase the degree of freedom in arranging exhaust pipes.

(Structure of the Invention) According to the present invention, the object 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, and a plurality of exhaust pipes each having a plurality of exhaust pipes connected to the exhaust port of the engine and an expansion chamber, and a In an engine equipped with an exhaust control valve that changes the road area, the valve shaft of the exhaust control valve provided in one of two adjacent exhaust pipes is non-coaxial and parallel to the valve shaft of the exhaust control valve provided in the other exhaust pipe. This is achieved by an engine exhaust control device characterized in that a rotary transmission mechanism for interlocking both valve shafts is provided near the centers of the adjacent exhaust pipes.

(Example) Fig. 1 is a plan view of an exhaust system of a motorcycle which is an embodiment of the present invention, Fig. 2 is a side view of the same, and Fig. 3 is a side view of a motorcycle using this exhaust system. FIG. 4 is a cross-sectional side view of a part of the exhaust control valve, and FIG. 5 is a cross-sectional view taken along the line V-V.

In FIG. 3, reference numeral 10 is a 4-stroke, 4-cylinder engine, which is mounted near the center of the vehicle body.

This engine IO has a cylinder 14 extending diagonally upward and forward from a crankcase 12. The exhaust system is cylinder 1
4 exhaust pipes 16 (16a to 16d) extending downward from the crankcase 12, an exhaust control valve assembly 18 connected to the rear end of each exhaust pipe 16, and this exhaust control valve assembly 18. Two exhaust pipes 16a are connected to the rear surface of the.

Two expansion chambers 22 (22a, 22b) are provided that collect the exhaust gases 16b, 16c, and 18d, respectively, and guide them to two mufflers 20 (20a, 20b).

In FIG. 3, 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 includes a plurality of butterfly-shaped exhaust control valves 34 (34a to 34d) that change the exhaust passage area of each exhaust pipe 16.
Equipped with. That is, this 'assembly 18 includes each exhaust pipe 16.
Circular holes (36a to 36
d), valve shafts 38a and 38c that pass through the respective circular holes 36a and 36d in the horizontal direction, a valve shaft 38b that passes through the circular holes 36b and 36c, and a lever 40a fixed to the inner ends of the valve shafts 38a and 38c. , 40d, and a lever 40b fixed to both ends of the valve shaft 38b.

40c and a link 42a connecting the rotating end of each lever 40
, 42b. That is, lever 40 and link 42
Thus, a link mechanism A is formed as a rotation transmission mechanism that rotates each valve shaft 38 synchronously. Note that the circular holes 36a, 3
6d is 36b.

It is located above and behind 36c. Also, this link mechanism A connects two adjacent exhaust pipes lea.

It traverses planes B and B connecting the centers of 16b, 16c, and 16d (FIG. 5). A circular valve plate 44 (44a to 44d) located within each circular hole 36 is fixed to each valve shaft 38.

A pulley 46 is fixed to the outer end of the valve shaft 38a, and the pulley 46 is forcibly rotated in both directions by a servo motor 50 via a wire 48. This servo motor 50 is
For example, based on the engine rotation speed detected from the ignition device 52 (see FIG. 2), each control valve 34 is controlled by the control circuit 54 to close in a rotation range where volumetric efficiency deteriorates and to open in other rotation ranges.

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 54 drives the servo motor 50 to close the exhaust control valve 34 in the medium speed range. Each exhaust control valve 34 is synchronously controlled by the link mechanism A to have the same opening degree.

The positive pressure wave caused by the opening of the exhaust valve of the engine IO 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 so that the exhaust flow path area is 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 with the wave is zero. At this time, the pulsation effect is canceled out, and a decrease in volumetric efficiency (occurrence of torque valley) in the medium speed range can be suppressed.

Furthermore, 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 exhaust control valve 34 is closed, it is possible to use an exhaust control valve 34 that reduces the exhaust flow path area by about 90% to about 10%.

In this embodiment, four exhaust pipes 16 are arranged in parallel below the crankcase 12 of an engine 10 for a motorcycle.
Since the exhaust pipe 16d is located above the inner exhaust pipes 16b and 16c, a large bank angle of the vehicle can be ensured, and cornering performance is improved. Note that this effect can be similarly obtained when there are three exhaust pipes and the left and right exhaust pipes are arranged higher than the central exhaust pipe.

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.

Also, as in this embodiment, some exhaust control valves (34a, 3
4d) to the other exhaust valve (34b.

34C), the appropriate exhaust control valve 3 can be adjusted to correspond to the difference in length due to the layout of each exhaust pipe 16.
4 can be shifted forward or backward to arrange it at an optimal position, which increases the degree of freedom in design.

Particularly, when the position of each exhaust control valve 34 is changed up or down, the traveling air is more likely to hit each exhaust control valve 34, thereby improving its cooling performance.

Also, it is preferable that the rotational transmission mechanism has a link configuration;
The present invention is not limited to this, and each valve shaft may be interlocked using gears.

Furthermore, the present invention is applicable not only to the case where there are four exhaust pipes,
This also includes applications where there are two exhaust pipes.

(Effects of the Invention) As described above, the present invention arranges the valve shafts of the exhaust control valves provided in two adjacent exhaust pipes non-coaxially and in parallel, and arranges both valve shafts near the middle of both exhaust pipes. It is linked by a rotation transmission mechanism installed in the. Therefore, multiple exhaust control valves can be controlled by one driving means such as a servo motor,
The control device becomes simple. Furthermore, since each valve stem is shortened, measures against elongation of the valve stem due to exhaust heat become simple or unnecessary. Furthermore, since the position of the adjacent exhaust control valve can be relatively freely changed in the length direction of the exhaust pipe or in the direction perpendicular to the exhaust pipe, there is also the effect of increasing the degree of freedom in design.

[Brief explanation of drawings]

FIG. 1 is a plan view of an exhaust system for a motorcycle that is an embodiment of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a side view of a motorcycle using this exhaust system, and FIG. FIG. 5 is a cross-sectional side view of the exhaust control valve of FIG. DESCRIPTION OF SYMBOLS 10... Engine, 16... Exhaust pipe, 18... Exhaust control valve assembly, 22... Expansion chamber, 34... Exhaust control valve, 38... Valve shaft, A... Rotation Link mechanism as a transmission mechanism, B... A plane connecting the centers of the exhaust pipes.

Claims (3)

[Claims] (1) An engine comprising 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 exhaust pipe to change the exhaust flow path area of each exhaust pipe. In this method, the valve shaft of the exhaust control valve provided on one of two adjacent exhaust pipes is disposed non-coaxially and parallel to the valve shaft of the exhaust control valve provided on the other exhaust pipe, and both valve shafts are interlocked. An exhaust gas control device for an engine, characterized in that a rotational transmission mechanism is provided near the middle of the adjacent exhaust pipes. (2) the engine is a motorcycle engine having a cylinder extending diagonally upward and forward from the crankcase;
The plurality of exhaust pipes are arranged in parallel so as to extend rearward from the front surface of the cylinder passing below the crankcase, and each of the exhaust control valves is disposed below the crankcase. The exhaust gas control device according to item 1. (3) Claims characterized in that the engine has at least three exhaust pipes, and the exhaust control valves located on the outside from the center in the width direction of the engine are arranged above the exhaust control valves located on the inside. 2. Exhaust control device according to item 2.