JPS6047452B2 - Secondary air supply device in internal combustion engine - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a secondary air supply system for purifying the exhaust gas by supplying secondary air into the exhaust gas of an internal combustion engine and reburning its unburned components. Regarding the supply device.

[Prior art]

One type of secondary air supply device is one that supplies secondary air from an air cleaner to the exhaust system using the pulsation of exhaust pressure of an internal combustion engine. Improved devices have also been developed that can prevent large amounts of exhaust gas from flowing back into the air cleaner, as proposed in Publication No. 50-147017.

The secondary air supply device includes a lead in a secondary air supply passage that connects the air cleaner to the exhaust manifold of the internal combustion engine, which opens and closes in response to pressure changes in the exhaust manifold and allows air to flow only to the exhaust manifold. A valve is provided, and temperature-sensitive actuation means is provided in the secondary air supply passage closer to the air cleaner than the reed valve, and is actuated when the ambient temperature reaches a predetermined temperature or higher to prevent the flow of exhaust gas to the air cleaner side. Some are equipped with a second valve.

As a result, in the secondary air supply device, when the exhaust gas flows to the second valve side when the reed valve malfunctions and the ambient temperature rises to a predetermined temperature or higher, the second valve is activated by the temperature-sensitive actuating means. This actuates to prevent exhaust gas from flowing toward the air cleaner.

[Problem that the invention seeks to solve]

Incidentally, in this type of secondary air supply device, it is preferable to provide means for quickly confirming malfunctioning conditions of the reed valve, such as damage. Preferably, the temperature-sensitive actuating means is actuated appropriately in response to actuation of the temperature-sensitive actuating means.

SUMMARY OF THE INVENTION The present invention aims to provide a secondary air supply device equipped with temperature-sensitive actuation means that can accurately actuate means for confirming malfunction of a reed valve. [Means for Solving the Problems] In order to solve the problems, the present invention provides a temperature-sensitive operating means in this type of secondary air supply device, which is fixedly provided in the secondary air supply passage. A permanent magnet that attracts and holds the valve body of the second valve in its open position; and a permanent magnet that is interposed between the permanent magnet and the valve body and becomes a non-magnetic substance when the ambient temperature reaches a predetermined temperature or higher to attract and hold the permanent magnet. A normally open type that is constructed of temperature-sensitive ferrite that reduces the force, is connected to a confirmation display means on a part of the permanent magnet, and is closed by the magnetic force of the permanent magnet when the temperature-sensitive ferrite becomes non-magnetic. Installing a reed switch.

[Operation of the Invention] Accordingly, in the present invention, when the reed valve is normal, the reed valve opens and closes in response to pressure fluctuations in the exhaust manifold, and directs the secondary air from the air cleaner to the second valve and the reed valve. This prevents air from flowing from the exhaust manifold to the air cleaner side.

Therefore, the temperature-sensitive ferrite constituting the temperature-sensitive operating means functions as a magnetic material that reaches a predetermined temperature. As a result, a magnetic field is formed between the permanent magnet, the temperature-sensitive ferrite, and the valve body of the second valve, and the permanent magnet attracts and holds the valve body through the temperature-sensitive ferrite, thereby opening the second valve.
During this time, no or almost no magnetic field is formed between the permanent magnet and the reed switch, so the reed switch is opened and the confirmation display means is deactivated. If the reed valve malfunctions due to damage or the like, the exhaust gas in the exhaust manifold flows into the vicinity of the second valve.

Therefore, as the ambient temperature rises, the temperature-sensitive ferrite reaches a predetermined temperature or higher and becomes a non-magnetic material, and the magnetic field formed between the permanent magnet, the temperature-sensitive ferrite, and the valve body disappears, and the permanent magnet is replaced. A magnetic field is formed between the reed switch and the reed switch.
As a result, the attraction and holding force of the permanent magnet to the valve body is reduced, the valve body is opened, and the second valve is activated to prevent exhaust gas from flowing toward the air cleaner side. Meanwhile, the reed switch is closed and the confirmation display means is activated in response to the actuation of the second valve, indicating the malfunction of the reed valve. [Effect of the invention] As described above, according to the present invention,
Since the confirmation display means is actuated in response to the operation of the second valve, it is possible to accurately check and confirm the malfunction status of the reed valve, and due to the structure of the temperature-sensitive actuation means, the means and its The confirmation method becomes compact.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 shows a schematic configuration of a secondary air supply device 10 including a reed valve 20 which is a second valve constituting a main part of the present invention, and includes an air cleaner 12 of a carburetor 11 and an exhaust manifold of an internal combustion engine 13. A well-known reed valve 16 that allows air to flow from the reed valve 20 and the air cleaner 12 to the exhaust manifold 14 is installed in series in the secondary air supply passage 15 that connects the reed valve 14 . As shown in FIGS. 2 and 3, the reed valve 20 includes a housing 21 having an inlet 21a and an outlet 21b, and is airtightly assembled into the housing 21 via a shock absorber 22. A valve seat 23, an annular sealing member 24 fitted into the opening of the valve seat 23, and a screw 2 attached to the lower end of the valve seat 23 as shown in the figure.
Lead 26 and stopper 27 fixed by 5 and 25
At both ends of the stopper 27, suction means 30, 30, which are temperature-sensitive operating means, are provided. As shown in an enlarged view in FIG. 4, the attraction means 30 is composed of a permanent magnet 31 embedded in the stopper 27, and temperature-sensitive ferrites 32, 32 fixed to both ends of the magnet 31 on the lead 26 side. Under normal conditions, the lead 26 is held open by suction as shown in the figure.

The temperature-sensitive ferrite 32 is made by mixing and firing metal oxide powder, and the ambient temperature is set to a predetermined temperature (for example, 120~120℃).
When the temperature exceeds 150°C, its function as a magnetic substance is deenergized and it becomes a non-magnetic substance. Further, in this embodiment, a reed switch 33 is disposed behind the magnet 31 of the attraction means 30.

The reed switch 33 is assembled to the housing 21 by a support member 34, and its lead wire 33a is connected to a warning lamp 35 serving as confirmation display means. Next, the operation of this embodiment configured as described above will be explained. When the internal combustion engine 13 is normally started, exhaust gas is periodically discharged into the exhaust manifold 14, and the inside of the exhaust manifold 14 becomes positive pressure. , the inside of the exhaust manifold 14 temporarily becomes negative pressure due to the overlapping timing of opening and closing of the intake and exhaust valves in the internal combustion engine 13.

As a result, the secondary air that has passed through the open reed valve 20 flows into the exhaust manifold 14 through the unillustrated lead of the reed valve 16, which opens and closes in response to pressure fluctuations within the exhaust manifold 14. Reed valve 1
Since the exhaust gas is prevented from flowing toward the air cleaner 12 by the unillustrated reed 6, the reed valve 2
0 (that is, the ambient temperature of the temperature-sensitive ferrite 32) does not rise to the predetermined temperature. Therefore, the temperature-sensitive ferrite 32 functions as a magnetic material. As a result, in the attraction means 30, a good magnetic field shown by the dashed line in FIG. 4 is formed, and the lead 26 is attracted and held in the open state as shown. By the way, if the reed valve 16 becomes inoperable due to breakage of its reed or the like, the exhaust gas in the exhaust manfold 14 flows to the reed valve 20.

Then, the ambient temperature of the reed valve 20 immediately rises to a predetermined temperature or higher, and the temperature-sensitive ferrite 32 becomes a non-magnetic material.
Therefore, the suction force of the suction means 30 decreases, and the lead 26
is seated on the sealing member 24 due to its self-returning force and becomes ready for operation. This then allows secondary air to pass through the exhaust manifold 14 through the reed 26 of the reed valve 20, which passes through and closes in response to pressure fluctuations within the exhaust manifold 14.
supplied within. Further, at this time, a magnetic field as shown by the two-dot chain line in FIG. 4 is formed in the adsorption means 30 due to the deenergization of the temperature-sensitive ferrite 32, so the reed switch 33 is activated and the warning lamp 35 is turned on. Note that due to the operation of the reed valve 20, the exhaust gas is transferred to the air cleaner 12.
When the flow to the side stops, the ambient temperature inside the reed valve 20 drops below a predetermined temperature, and the temperature-sensitive ferrite 32 becomes a magnetic material, but when the reed 26 is operating normally, the temperature-sensitive ferrite 32 and the lead 26 Since the required interval is formed between the leads 26, the leads 26 are not held open by the suction means 30.

Furthermore, even if the reed 26 were to be suctioned by the suction means 30, the suction force of the suction means 30 would immediately decrease in the same way as immediately after the breakage of the reed valve 16 described above. Operates remotely. As described above, according to this embodiment, since the display means 35 is operated in response to the operation of the reed valve 20, which is the second valve, it is possible to accurately confirm whether the reed valve 16 is malfunctioning. Moreover, due to the structure of the suction means 30 which is the temperature-sensitive operating means, the structure of the combination with the same means 30 and the reed switch 33 which is the main part of the confirmation means can be made compact.

Note that when implementing this embodiment, the arrangement position, number, and shape of the suction means 30 may be changed as appropriate. Further, instead of the warning lamp 35, a warning buzzer or other known appropriate confirmation display means may be used.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a secondary air supply device including a reed valve which is a second valve constituting the main part of the present invention, Fig. 2 is a longitudinal cross-sectional view of the reed valve, and Fig. 23 is a Fig. 2 3-
3 is a longitudinal cross-sectional view taken along line 3, and FIG. 4 is a cross-sectional view taken along line 4--4 in FIG. Explanation of symbols, 10...Secondary air supply device, 11.
・Carburetor, 12...Air cleaner, 13...
... Internal 7 combustion engine, 14 ... Exhaust manifold,
15... Secondary air supply passage, 16... Exhaust manifold side reed valve, 20... Second
Reed valve, -26...Reed,
27... Stopper, 31... Permanent magnet, 3
2... Temperature-sensitive ferrite, 33... Freed switch, 35... Warning lamp.

Claims (1)

[Claims] 1. A reed valve is provided in the secondary air supply passage that connects the air cleaner to the exhaust manifold of the internal combustion engine, and opens and closes in response to pressure changes in the exhaust manifold to allow air to flow only to the exhaust manifold. A second valve is provided within the secondary air supply passage closer to the air cleaner than the reed valve, and is actuated when the ambient temperature reaches a predetermined temperature or higher to block the flow of exhaust gas to the air cleaner side. In the secondary air supply device, the temperature-sensitive actuating means includes a permanent magnet that is fixedly provided in the secondary air supply passage and attracts and holds the valve body of the second valve in its open position; A part of the permanent magnet is made of a temperature-sensitive ferrite that is interposed between the permanent magnet and the valve body and becomes a non-magnetic material when the ambient temperature exceeds a predetermined temperature, reducing the attraction and holding power of the permanent magnet. A secondary air supply device for an internal combustion engine, characterized in that a normally open reed switch is connected to confirmation display means and is closed by the magnetic force of the permanent magnet when the temperature-sensitive ferrite becomes non-magnetic.