JP3213852B2 - Engine exhaust purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification apparatus for purifying exhaust gas generated by a two-cycle or four-cycle engine used as a vehicle or other prime mover by injecting secondary air.

[0002]

2. Description of the Related Art A secondary air inlet pipe connected upstream of an exhaust passage of an engine and a check valve attached thereto is conventionally known (Japanese Utility Model Laid-Open No. 60-95116). When the check valve is directly connected to the introduction pipe in this manner, a metal pipe having high heat resistance and high rigidity is used for the introduction pipe, so that engine vibration is transmitted to the exhaust pipe and the introduction pipe, and the check valve is further checked. There is also a disadvantage that the action of the check valve is transmitted to the valve to make the action of the check valve unstable or to apply a repeated load.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce vibration applied to a check valve from a secondary air introduction pipe connected to an exhaust passage.

[0004]

According to a first aspect of the present invention, a check valve is provided in a secondary air passage, and an outlet side of the check valve is connected to an upstream side of an exhaust passage of the engine. In the exhaust gas purification device, an upstream portion in the exhaust passage
Installed a catalytic converter with a cloth catalyst wound around a perforated tube.
And a secondary air introducing cylinder for introducing secondary air into the perforated tube.
Was wound with a cloth catalyst immediately after the engine exhaust port.
It is connected to the upstream part of the perforated pipe, and heat-resistant
And the length of secondary air that is rigid and does not reach the check valve
The inlet pipe is connected, and the check valve and the inlet pipe are connected by a flexible connecting pipe.

[0005]

In the above means, even if the introduction pipe is vibrated by the engine, since the flexible connection pipe is interposed between the introduction pipe and the check valve, the vibration of the introduction pipe is cut off by the connection pipe. Not transmitted to the check valve.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, reference numeral 1 denotes a motorcycle, 2 denotes a frame thereof, 3 denotes a head pipe, 4 denotes a left and right main frame, and 5 denotes a pivot plate. The seat rail 6 extends from the cross member of the main frame 4 and is reinforced by the rear frame 7 to support the seat 8. A cushion 11 is provided between the cross arm 6a of the seat rail 6 and the swing arm 10 for the rear wheel 9, which is pivotally attached to the pivot plate 5.
Is interposed.

As the engine 12, a water-cooled two-stroke engine is used.
Are fixed to the frame 2 by stays 13 and 14 and a pivot plate 5 extending downward from the frame. As shown in FIG. 3, the frame 2 is provided with air cleaner mounting seats 15, 16 and a reed valve mounting seat 17 which will be described later on the cross members 4a and 6a, and a fixing screw hole is formed in each of them. .

[0008] An air cleaner 19 is connected to the engine 12 via a carburetor 18, and an exhaust pipe 21 is connected to an exhaust port 20 a of a cylinder 20. A reed valve 22 is provided upstream of the exhaust pipe 21 as a check valve for introducing secondary air using the pulsation of exhaust gas.
Fixed to The inlet side of the reed valve 22 is connected to a connecting portion 19a (FIG. 4) provided in a lower part of the air cleaner 19 through a rubber inflow pipe 23, and the outlet side of the reed valve 22 is connected to a rubber connecting pipe. 24, and a heat-resistant metal introduction pipe 25 is further connected by fitting, and a flange 25a at the tip is fixed to the exhaust pipe 21. Since the introduction pipe 25 is arranged along the high-temperature cylinder 20, it is desirable that the length of the introduction pipe 25 is 300 mm or more.

As shown in FIG. 5, a reed valve 22 is provided in a valve chamber formed by a bottom plate 27 and a case 27a.
a, a valve seat 28b and a stopper 28c are integrally sealed, and a pair of mounting pieces 29 shown in FIG. When a negative pressure is generated due to the pulsation of the exhaust gas in the exhaust pipe 21, the reed valve 22 separates the reed 28a from the valve seat 28b and moves in a direction indicated by an arrow in FIG.
The secondary air is circulated, and when a positive pressure is generated, the lead 28a
The valve seat 28b is closed to prevent backflow of exhaust gas, and the secondary air is introduced into the exhaust gas to burn unburned components in the exhaust gas.

In FIG. 1, reference numeral 30 denotes a front wheel, 31 denotes a radiator of the engine 12, 32 denotes a fuel tank, 34 denotes a front cowl, 35 denotes a seat cowl, 36 denotes a side cowl, and 37 denotes a drive chain.

FIG. 6 is an exploded view of the secondary air introducing system. The air cleaner 19 has mounting holes 38 and 39 provided on its outer peripheral edge.
The mounting seats 15, 16 of the frame 2 are
And the reed valve 22 is screwed through the mounting piece 29.
0 is fixed to the mounting seat 17. Each tube 23, 24,
A clip 41 is used as a connection portion of the exhaust pipe 25, and a flange 25 a at the tip is connected to an inlet 42 provided in the exhaust pipe 21 via a gasket 43.

The exhaust pipe 21 extends forward from the front part of the cylinder 15, further curves laterally to the rear, has an expansion chamber 44 at an intermediate part, and is connected to a muffling chamber 45 at a rear end. An outer wall 44b in which glass wool 44a is provided for soundproofing is provided on the outer periphery of 44. And the above introduction port 4
Downstream of the first catalytic converter 46 for exhaust gas purification
Is provided. The catalytic converter 46 has a number of small holes 47 drilled in the exhaust pipe 21 as shown in FIGS. 7 and 8 as a straight one, a cross catalyst carrier 48 is wound around the outside thereof, and a semi-cylindrical one is formed. A pair of covers 49 hermetically covers the air, and burns a part of the unburned components in the exhaust gas to purify and raise the temperature, thereby improving the reaction in the next converter. . Further, the cross catalyst carrier 48 is obtained by supporting a catalyst on a cloth-like body. Exhaust gas enters and exits through the small holes 47 and comes into contact with the catalyst to promote the reaction.

An inner pipe 50 connected to the muffling chamber 45 is inserted into the rear part of the exhaust pipe 21, and the tip of the inner pipe 50 is connected to the expansion chamber 4.
4, a honeycomb type multi-channel catalytic converter 51 is attached to the tip. Further, the rear end of the exhaust pipe 21 and the inner pipe 50 are connected at a welded portion W.

In the catalytic converter 51, as shown in FIGS. 9 and 10, a honeycomb catalyst carrier 53 made of a corrosion-resistant metal or ceramic is held in a cylindrical body 52, which is referred to as a corrugated mesh for buffering. A heat-resistant elastic body 54 having a corrugated curved shape is wound around a wire mesh and covered with a pair of semi-cylindrical covers 55.

The expansion chamber 44 surrounding the catalytic converter 51
A pair of semi-cylindrical inner walls 57 is mounted on the inner periphery of the base via a heat-resistant elastic body 56, and the cover 55 is connected to the lower inner wall 57 via a stay 58. With this configuration, the catalyst carrier 53 is disposed in the expansion chamber 44 and is resistant to vibration of the exhaust pipe 21 by the heat-resistant elastic bodies 54 and 56.
Heavily buffered. Further, since the expansion chamber 44 has a double wall, noise emission is reduced.

Next, FIG. 11 shows a different embodiment of the inner tube 50. The inner tube 50 is composed of a front inner tube 50a and a rear inner tube 50b.
And is fitted in the fitting portion 50c in a lightly press-fitted state. Thereby, expansion and contraction accompanying the temperature change of the inner tube 50 can be absorbed.

In FIG. 12, a step portion 59 is provided at the fitting portion 50c, and the ring-shaped gasket 60 is connected to the step portion 59.
The gasket 60 is held by a stopper ring 61 attached to one side and fixed to one side.
The airtightness of c can be kept high.

FIGS. 13 and 14 show another embodiment relating to the expansion chamber and the means for fixing the catalytic converter provided in the expansion chamber.
1 includes a pair of legs 61a extending at a narrow interval and two pairs of front and rear legs 61b extending at a wide interval.
Is directly welded to the inner surface of the exhaust pipe 21.

The inner surface of the exhaust pipe 21 has legs 61.
The glass wool layer 62 and the inner walls 63 and 64 for holding the glass wool layer 62 are laminated so as to avoid the welded portions a and 61b.

By employing this configuration, the catalytic converter 51 can be integrally connected to the exhaust pipe 21.
And the sound absorbing effect of the glass wool layer 62 and the inner wall 63,
64 can perform the soundproofing effect.

With the above construction, secondary air is intermittently supplied into the exhaust gas from the reed valve 22 by the pulsation of the exhaust gas discharged from the engine 12, and the catalytic converter 46
And 51 to promote the purifying action. And check valve 22
Since the rubbery and flexible connecting pipe 24 is interposed between the gas inlet and the introducing pipe 25, the introducing pipe 25 is fixed to the exhaust pipe 21, and even if it vibrates together with the exhaust pipe 21, Is not transmitted to the reed valve 22.

Further, since the connecting pipe 24 is flexible, even if there is a slight shift between the mounting position of the reed valve 22 and the mounting position of the introduction pipe 25, the pipe can be formed and the assembling can be easily performed. It should be noted that another check valve that performs the same operation can be used instead of the reed valve 22 described above. In addition, introduction pipe 2
The communication position of the exhaust passage 5 with the exhaust passage is not limited to the above-described exhaust pipe 21 but may be the cylinder 20 side.

Next, another embodiment which is used in place of the exhaust pipe 21 is shown in FIGS. In FIG. 15, reference numeral 70 denotes an exhaust pipe, 71 denotes a front catalytic converter provided at the front of the exhaust pipe 70, 72 denotes an expansion chamber, 73 denotes a honeycomb type rear catalytic converter, and the rear catalytic converter 73 denotes a front end of an inner pipe 74. The rear part of the inner pipe 74 is a tail pipe 74a forming the rear part of the exhaust pipe 70, and is inserted into the silencer 45 and fixed. The front catalytic converter 71 has an L-shaped curved portion and a lateral curved portion, so that the front half 71 a
And the latter half 71b. First half 71a
The inside of the inner tube 75 is shown in FIGS.
Are connected to each other, and a large number of small holes 77 are formed in the perforated tube 76. A large-diameter introduction hole 7 for introducing secondary air is further provided.
8 are drilled. The porous tube 76 is formed by welding two halves having a substantially L shape in a side view and having a semicircular end portion at a diameter portion.

A so-called cloth catalyst 79 formed by attaching a catalyst to a flexible tape-like metal net is wound around the outer periphery of the perforated tube 76, and the exhaust gas passing through the perforated tube 76 passes through the small holes 77. Then, the cloth catalyst comes into contact with the cloth catalyst and returns to the inside through another small hole 77. And this cloth catalyst 79 is used by stacking two sheets, and one cloth catalyst 79a is
As is clear from FIG. 17, the tip is inserted inside the introduction hole 78, bent along the half circumference of the edge of the introduction hole 78 and stopped with the adhesive tape 80 a, and the other portion is downstream to the outer peripheral surface of the porous tube 76. It is wrapped in a gaiter shape counterclockwise toward the side. The other cloth catalyst 79b is bent at the tip on the remaining half circumference side of the introduction hole 78, and is stopped with the adhesive tape 80b.
Wrap the top clockwise to restrain the ends. By winding in this manner, the cloth catalyst 79 is formed in two or more layers,
Further, all of the small holes 77 adjacent to the introduction hole 78 can be covered, and the porous tube 76 can be used effectively. The adhesive tapes 80a and 80b are burned by the passage of the exhaust gas. However, the cloth catalyst 79 does not shift due to the bent portion formed at the tip and the absence of strong tension.

A catalyst device in which a cloth catalyst 79 is wound around a perforated tube 81 having small holes 82 is also provided inside the rear half 71b. And the front half 71a and the rear half 71b are
Covered with 3. The outer plate 83 is a vertically divided front outer plate 83a.
₁ , 83a ₂ and rear outer plates 83b ₁ , 83b _2. First, the outer plates 83a ₁ and 83b _{1 on} one side are integrated by welding, and the outer plates 83a ₂ and 83b _{2 on the} other side are welded. Be integrated.

[0026] Among these, secondary air introduction pipe on the outer plate 83a ₁ having a mounting flange 84a, as shown in FIG. 19 84
However, the distal end 84b is welded so as to project inward, and the distal end 84b is fitted in the introduction hole 78 to introduce secondary air into the exhaust flow. On the outer surface of the outer plate 83, a fixing nut 85 for mounting the protector at an interval in the radial direction from the outer plate 83 is substantially uniformly welded.

When covering the catalyst body in which the cloth catalysts 79, 79 are wound around the perforated tubes 76, 81 with the outer plate 83, as shown in FIG.
86 is inserted. The outer plates 83a ₁ , 83b ₁ integrated at the welded portion 87a and the outer plates 83a ₂ , 83b ₂ integrated at the welded portion 87b are connected to the welded portions 88a, 88a shown in FIG.
The catalytic converter 70 is formed by coupling at 88b. Further, a connection cylinder 89 having a mounting flange 89a is externally fitted to the inner tube 75, and is fixed to a front end of the outer plate 83 at a welded portion 89b.

In order to dissipate heat from the outer plate 83 and prevent the hot outer plate 83 from coming into contact with other objects, a front protector 90 and a rear protector 91 shown in FIG. Installed with bolts not shown. The front protector 90 includes half portions 90a and 90b, each of which has a bolt hole 92 at a position corresponding to the fixing nut 85, and one half 90a has a secondary air introduction cylinder 84. Is provided. The rear protector 91 also includes half portions 91a and 91b, and the bolt holes 92 are formed as described above, and are bolted to the fixing nuts.

As described above, in the front catalytic converter 71 of the exhaust pipe 70, since the cloth catalyst 79 is started to be wound from the position where the secondary air introduction cylinder 84 is connected, the arrangement section of the cloth catalyst 79 is lengthened. And a sufficient reaction can be caused.

[0030]

As described above, according to the present invention , the upper part of the exhaust passage
Catalytic converter with a cloth catalyst wrapped around a perforated tube
And introducing secondary air into the perforated tube.
Wrap a cloth catalyst around the cylinder immediately after the engine exhaust port
Connected to the upstream of the perforated pipe,
At a later position, wind the cloth catalyst in the catalytic converter.
By introducing secondary air upstream of the attached perforated tube.
If some of the unburned components in the exhaust are burned and purified,
In both cases, the temperature of the cloth catalyst is raised to promote the reaction and purify the exhaust.
Action can be promoted. Also, when the cloth catalyst is
Wound from the connection position of the secondary air introduction cylinder in the hole pipe
The length of the section where the cloth catalyst is placed can be extended.
As a result, a sufficient exhaust gas purification reaction can be caused. Ma
The inlet pipe of the secondary air connected to the exhaust passage was made to have a length that does not reach the check valve, and the inlet pipe and the check valve were connected by a flexible connecting pipe, so that the inlet pipe was integrated with the engine. Even if the check valve vibrates, the vibration is not transmitted to the check valve. Therefore, the opening / closing operation which may be caused by the check valve vibration or a repetitive load can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle embodying the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a perspective view of a frame.

FIG. 4 is a plan view of a connecting portion between a reed valve and an air cleaner.

FIG. 5 is a longitudinal sectional view of a reed valve.

FIG. 6 is an exploded perspective view of a secondary air system.

FIG. 7 is a longitudinal sectional view of an exhaust converter on the upstream side.

FIG. 8 is a cross-sectional view of the same.

FIG. 9 is a longitudinal sectional view of an exhaust converter on the downstream side.

FIG. 10 is a cross-sectional view of the same.

FIG. 11 is a longitudinal sectional view of another embodiment of the exhaust converter on the downstream side.

FIG. 12 is a partial longitudinal sectional view of still another embodiment of the exhaust converter of the above.

FIG. 13 is a side view of another embodiment of the exhaust converter.

14 is a longitudinal sectional view of an expansion chamber using the exhaust converter of FIG.

FIG. 15 is a plan view of another embodiment of the exhaust pipe.

16 is a side view of the catalyst unit of FIG.

FIG. 17 is a sectional view taken along line 17-17 of FIG. 16;

18 is a front side view of the exhaust pipe of FIG.

19 is a sectional view taken along line 19-19 in FIG. 18;

FIG. 20 is a sectional view of a joint portion of an outer plate.

FIG. 21 is an exploded perspective view of the protector.

[Explanation of symbols]

Reference Signs List 18 air cleaner 20 cylinder 21, 70 exhaust pipe 22 reed valve (check valve) 24 connecting pipe 25 introduction pipe 46, 51, 71 catalytic converter 58, 61
Stay 84 Secondary air introduction cylinder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F01N 3/34 F01N 3/30 F02B 77/00

Claims (1)

(57) [Claims] 1. A check valve is provided in the secondary air passage, the exhaust gas purifying apparatus for an engine which is connected to the upstream side of the exhaust passage of the engine outlet side of the reverse valve, upstream portion of the exhaust passage
Installed a catalytic converter with a cloth catalyst wound around a perforated tube.
And a secondary air introducing cylinder for introducing secondary air into the perforated tube.
Was wound with a cloth catalyst immediately after the engine exhaust port.
It is connected to the upstream part of the perforated pipe, and heat-resistant
And the length of secondary air that is rigid and does not reach the check valve
An exhaust gas purifying apparatus for an engine , wherein an inlet pipe is connected, and the check valve and the inlet pipe are connected by a flexible connecting pipe.