JPS5939241Y2 - air switching valve - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a secondary air switching valve in a secondary air injection device used for the purpose of purifying automobile exhaust gas.

(Technical background) One of the methods to reduce carbon monoxide (CO) and unburned hydrocarbons (HC), which are harmful components in the exhaust gas of automobile internal combustion engines, is to install a secondary gas near the exhaust valve of the engine. A method is known in which air is injected to oxidize and detoxify the Co and HC. In this method, in order to improve the durability of the air pump that pumps the secondary air, while injecting the secondary air, the atmosphere is It is also known that depending on the operating condition of the engine, it is necessary to stop the injection of secondary air to prevent overheating of the exhaust pipe, etc., and to release the air from the air pump to the atmosphere.

In other words, the secondary air switching valve is required to have the function of relieving the secondary air by its pressure, and switching and controlling it according to the engine operating conditions. Continuing to inject air may cause afterburn, so a function is required to stop injecting secondary air and release air to the atmosphere for a few seconds immediately after deceleration. In order to prevent overheating of the exhaust manifold, etc., it was necessary to release secondary air to the atmosphere.

(Prior Art and its Problems) As described above, secondary air switching valves are required to have a plurality of functions, and therefore, conventionally, a plurality of valves have been used independently in correspondence with each function.

Therefore, in the past, there were problems in that the use of multiple valves made secondary air switching expensive, and it took time to assemble it into a vehicle.

(Purpose of the present invention) The present invention was devised in view of the above points. The aim is to provide a single air switching valve that remotely performs the complex functions required of a secondary air switching valve, such as the function of releasing secondary air to the atmosphere when under load.

(Basic structure and operation of the present invention) In order to achieve the above object, the present invention provides a housing 16 having a secondary air inflow passage 25, a secondary air outflow passage 26, and an air discharge passage 27; The secondary air inflow passage 25 and the air discharge passage 27 are arranged within the secondary air inflow passage 25 and the air discharge passage 27.
a partition plate 21 having a hole that partitions between the two passages and communicates between the two passages; A valve body 19 made of an elastic body that passes through the hole of the partition plate 21, a spring 18 that biases the valve body 19 toward the open end side of the secondary air outflow passage 26, a first diaphragm 15, and this first diaphragm 15. a second diaphragm 5 that is arranged parallel to and apart from the first diaphragm 15 by a predetermined distance and has a larger pressure receiving area than the first diaphragm 15; a spacer 12 that always maintains a predetermined distance between the second diaphragm 5 and the first diaphragm 15; An atmosphere opening hole 24 is formed between the housing 16 and the first diaphragm 15.
an atmospheric pressure chamber 11 into which atmospheric pressure is introduced through the diaphragm 11; a second negative pressure chamber 9 formed outside the second diaphragm 5 and communicating with the first negative pressure chamber 10 via an orifice 8;
A shirt l-3 that is fixed to the second diaphragms 15, 5 and moves according to the displacement of the first and second diaphragms 15, 5, and the shaft 3 are moved from the second negative pressure chamber 9 to the first negative pressure chamber 10. The valve body 19 is slidably supported on the shaft 3, and the shaft 3 is provided with a stopper 17.20 that limits the amount of movement of the valve body 19. , and the valve body is made somewhat larger than the hole in the partition plate.

With the adoption of the above basic configuration, the air switching valve of the present invention operates as follows.

That is, during steady running and no-load operation of the engine, the intake manifold negative pressure is introduced into the first negative pressure chamber 10 and the second negative pressure chamber 10.
Due to the pressure difference between the negative pressure chamber 9 and the atmospheric pressure chamber 11 into which atmospheric pressure is introduced, secondary air is caused to flow toward the secondary air outflow passage 26.
When the pressure of the next air exceeds a predetermined pressure, the valve body 19 climbs over the partition plate 21 and opens the air release passage 27. Also, during deceleration, the first negative pressure chamber 10 receives a sudden increase in negative pressure. Air is discharged from the discharge passage 27 due to the pressure difference between the first negative pressure chamber 10 and the second negative pressure chamber 9.

(Effects of the present invention) The air switching valve of the present invention satisfies the functions required of a secondary air switching valve using a pure mechanical component called a diaphragm, so it has sufficient durability despite having complex functions. It has an excellent effect of being able to be maintained.

(Explanation of Examples) The present invention will be described below with reference to embodiments shown in the drawings.

1 is a cover, 2 is a cover lower, 16 is a housing,
These are joined together by seaming, and first and second negative pressure chambers 10, 9 and an atmospheric pressure chamber 11 are formed inside, and the first negative pressure chamber 1
0, the atmospheric pressure chamber 11 is partitioned by a first diaphragm 15.

The outer edge of the first diaphragm 15 is sandwiched between the cover lower 2 and the housing 16, and the shaft 3 is attached to the two pressure receiving plates 14 and the spacer 12 in the center.

The first and second negative pressure chambers 10 and 9 are separated by a second diaphragm 5.

The second diaphragm 5 is arranged parallel to the first diaphragm 15, and its pressure receiving area is larger than that of the first diaphragm.

Further, its outer edge portion is sandwiched between the cover 1 and the cover lower 2, and its center portion is sandwiched between two pressure receiving plates 4 and a check sheet 6.
It is also tightened and fixed to the shirt I-3.

This check sheet 6 is made of an elastic material such as rubber.

The shaft 3 passes through the housing 16, and a valve body 19 is slidably fitted to the other end thereof.

This valve body 19 is made of an elastic body such as rubber, and when the valve body 19 moves upward, the outermost diameter of the valve body 19 becomes the hole 21a of the partition plate.
It is slightly larger than the inner diameter of the hole 21a so that it can be sealed.

25 is a secondary air inflow passage into which the secondary air pumped by the air pump 28 first enters; 26 is an air outflow passage connected to the exhaust port of the engine for supplying secondary air; Outflow passage 26 is pipe outlet 3
It is formed by 1.

Reference numeral 27 denotes an air discharge passage for discharging secondary air to the atmosphere, and is formed in the housing 16.

Reference numeral 21 denotes a partition plate that partitions the secondary air inflow passage 2 and the secondary air outflow passage 26, and the central hole 21a abuts against the valve body 19 and is used as a valve seat.

Reference numeral 17 and 20 denote a stopper fixed to the shaft 3, and the upper stopper 17 is fixed at a position where it hits the stopper housing 16 when the valve body moves upward to seal the hole 21a.

7 is a small hole, which is normally closed by a check sheet 6.

8 is an orifice with an extremely small diameter compared to the small hole 7;
, which connects the second negative pressure chambers 10 and 9.

13.18 is a spring that determines the operating characteristics.

Arrows A, A, and C in the figure indicate air flow.

Reference numeral 23 denotes a negative pressure introduction pipe into which negative pressure from an intake manifold (not shown) is introduced.

A pressure introduction pipe 22 is connected to a solenoid valve 29, and when the solenoid valve 29 opens, atmospheric air is introduced.

This solenoid valve 29 is normally closed and opened in response to a signal from a sensor in a dangerous situation such as abnormal catalyst overheating.

Reference numeral 24 denotes an atmosphere opening hole for introducing atmospheric pressure into the atmospheric pressure chamber 11.

Reference numeral 30 indicates an internal combustion engine of the automobile, and the air pump 28 is rotationally driven by the engine 30.

To explain the operation, for example, when the engine is in steady running or no-load operation, negative pressure is introduced into the intake manifold through the negative pressure introduction pipe 23.

In this case, the first and second negative pressure chambers 10 and 9 are connected to the orifice 8.
Since the pressure is the same through the first negative pressure chamber 10 and the atmospheric pressure chamber 11, the first diaphragm 15 moves upward in the figure, and the valve body 19 is also regulated by the stopper 20. The secondary air outflow passage 26 is opened, the air release passage 27 is closed, and the secondary air inflow passage 25 is opened.
The entire amount of secondary air is led to the secondary air outflow passage 26.

In this state, when the pressure of the secondary air exceeds a predetermined pressure determined by the spring 18, the valve body 19 climbs over the central hole 21a of the partition plate 21 to open the hole 21a, and a part of the secondary air is released into the air release passage 27. This prevents the pressure from rising abnormally due to leakage.

When the engine is operated at full load, the intake manifold negative pressure becomes smaller, so the negative pressure in the first and second negative pressure chambers 10.9 also becomes smaller, and the pressure difference between them and the atmospheric pressure chamber 11 becomes smaller. The force of the spring 13 is overcome and the diaphragms 5, 15 are displaced downward, and with this movement, the valve body 19 is forcibly lowered by the stopper 17.

Thereby, the air outflow passage 26 is closed and the secondary air is completely guided to the air discharge passage 27.

Further, when the engine state changes from steady running to deceleration, if the secondary air continues to flow from the steady running state, that is, from A to the mouth, it may cause afterburn.

However, during deceleration, the negative pressure in the first negative pressure chamber 10 increases rapidly, so a pressure difference is created between the first negative pressure chamber 10 and the second negative pressure chamber 9, and this pressure difference causes the second diaphragm 5 to Since the receiving pressure applied to the first negative pressure chamber 10 is larger than the receiving pressure applied to the first diaphragm 15 due to the pressure difference in the atmospheric pressure chamber 11, (the pressure receiving area of the second diaphragm 5 is larger than the receiving pressure of the first diaphragm 15). (Because the area is larger than
is closed, and the entire amount of secondary air is guided to the air release passage 27.

After a few seconds, when the pressure difference between the first and second negative pressure chambers 10°9 becomes smaller through the orifice 8, the valve body 19 rises again and the flow of secondary air shifts from A to the mouth, returning to a steady running state. return.

Also, if a danger signal is generated due to abnormal overheating of the catalyst, etc., the solenoid valve 29
opens, the atmosphere is introduced from the pressure introduction pipe 22 into the second negative pressure chamber 9, and the pressure rises, so that the second diaphragm 5
The receiving force applied to the first diaphragm 15 overcomes the receiving force applied to the first diaphragm 15, and the shaft 3 is displaced downward.

Therefore, the valve body 19 descends together with the stopper 17 fixed to the shaft 3, closing the secondary air outflow passage 26 and opening the air discharge passage 27, allowing the secondary air to escape.

[Brief explanation of the drawing]

The drawing is a sectional view showing one embodiment of the air switching valve according to the present invention. 3...Shaft, 15, 5...1st,
Second diaphragm, 8...orifice, 10,
9...First and second negative pressure chambers, 11...Atmospheric pressure chamber, 19...Valve opening body, 25...Secondary air inflow passage, 26... ...Secondary air outflow passage, ...
...Air release passage. 7

Claims (1)

[Claims for Utility Model Registration] A housing having a secondary air inflow passage, a secondary air outflow passage, and an air discharge passage, and a housing disposed within the housing between the secondary air inflow passage and the air discharge passage. a partition plate having a hole that partitions the two roads and communicates between the two roads;
a valve body made of an elastic body that is seated at the open end of the secondary air inflow passage and passes through the hole of the partition plate; and a spring that biases the valve body toward the open end of the secondary air outflow passage. a first diaphragm, a second diaphragm arranged parallel to the first diaphragm at a predetermined distance and having a larger pressure receiving area than the first diaphragm, and a spacer that always maintains a predetermined distance between the second diaphragm and the first diaphragm. , an atmospheric pressure chamber formed between the housing and the first diaphragm and introducing atmospheric pressure through an atmospheric opening hole;
A first negative pressure chamber is formed between the first diaphragm and the second diaphragm and introduces negative pressure into the intake manifold of the internal combustion engine via a negative pressure introduction pipe, and an orifice is formed outside the second diaphragm. a second negative pressure chamber that communicates with the first negative pressure chamber through a shaft; a shaft that is fixed to the first and second diaphragms and moves in response to displacement of the first and second diaphragms; a spring that presses in a direction from the negative pressure chamber toward the first negative pressure chamber, a stopper that allows the shaft to slidably support the valve body, and that limits the amount of movement of the valve body on the shaft; , and the valve body is slightly larger than the hole in the partition plate.