JPH07247942A - Air volume control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the sealability due to the deformation of a cylindrical elastic sealing member made of rubber which has been conventionally used to the barrel shape under the compressed condition after warming-up, and prevent the instability of the idling speed and the increase of the fuel consumption associated with increase in the idling speed. CONSTITUTION:A pin 4 of a temperature sensing member 3 is advanced downward to lower a rod 5 in the warming-up condition where the temperature of the cooling water of the engine is high. A valve 9 is pushed by a spring 10 to be pressed against a seat 6. The rod 5 compresses an elastic sealing member 13A made of synthetic rubber of bellows shape and is lowered to achieve the relief. Sealing parts 13a, 13b are abutted on a flat part formed on a stepped part of the rod 5, and a flat part formed on the valve 9 to seal the leakage of the air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air quantity control device for an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine equipped with a fuel injection device, a throttle body is equipped with an air amount control device for correcting the amount of air supplied to the engine when operating at a low intake air amount with a small throttle valve opening.

This air amount control device responds to the temperature of the engine and controls the idle speed of the engine so as to increase the amount of supplied air at the time of cold start and decrease the amount of supplied air as the engine warms up. .

This type of air amount control device is disclosed in Japanese Utility Model Publication 5-5.
As disclosed in Japanese Patent No. 7360, the air flowing through the intake passage is sucked from an inlet provided on the intake cylinder side wall upstream of the throttle valve, bypasses the throttle valve, and an outlet provided on the side wall downstream of the throttle valve. An auxiliary air passage is formed to flow out to.

A valve is provided in the middle of the auxiliary air passage, which operates by a temperature-sensitive member that expands and contracts when the temperature of the internal combustion engine is warmed up. When the temperature is low, the opening area of the auxiliary air passage is increased to increase the internal combustion engine. The amount of air supplied to the internal combustion engine is increased, the opening area is reduced as the engine warms, and the amount of air supplied is reduced, and the amount of air from the low temperature of the internal combustion engine to the completion of warming up is controlled according to the temperature.

5 to 8 show the detailed structure of such a conventional flow rate control unit. This prior art is proposed by the applicant. 1 is the throttle body itself, 2
Is an auxiliary air passage, 2a is its inlet, and 2b is its outlet. Reference numeral 3 denotes a temperature-sensitive member, the upper portion of which is not shown faces the internal combustion engine cooling water passage, and the pin 4 moves forward and backward in response to the cooling water temperature. That is, when the temperature rises, pin 4
Moves downward, and when the temperature drops, the pin 4 retracts upward.

The state shown in FIG. 7 is during warm-up of the engine.
The figure shows when the cooling water temperature is 75 ° C. 5 is a rod that is slidable up and down, and the upper part of which is fitted to the temperature sensitive member 3,
It is moved up and down by the lower edge of. 6 is a (valve) seat screwed to the throttle body 1; 7 is a rod 5
A spring retainer that engages the first step 5a of the
Is a compression spring interposed between the spring retainer 7 and the seat 6, and 9 is a valve that cooperates with the seat 6,
It is fitted to the lower part of the rod 5 and is constantly urged downward by a relief spring 10 interposed between the rod 5 and the spring retainer 7. Reference numeral 11 is a washer fitted to the lower end of the rod 5.

Relief spring 10 and washer 11
Has a relief mechanism 12 in which the rod 5 can move up and down independently of the valve 9 even after the engine is warmed up. The relief mechanism 12 has the pin 4 advanced downward as shown in FIG. 7 after the engine is warmed up. By doing so, the temperature sensitive member 3 is protected from being damaged.

Reference numeral 13 is an elastic sealing member such as rubber, which is formed in a cylindrical shape and is press-fitted into the rod 5 to the extent that it does not move due to engine vibration or the like, and the upper end thereof is the lower end surface of the large diameter portion 5b of the rod 5. It is in contact with a certain second step 5c.

The lower end of the seal member 13 contacts the shoulder portion 9b of the valve 9 in a state where the water temperature at which the rod 5 moves downward is about 60 ° C. or more. 5 and 6 are diagrams showing the entire conventional air amount control device including the flow rate control unit of FIG. 7, FIG. 5 shows a state where the cooling water temperature of the internal combustion engine is 70 ° C., and FIG. 6 shows a cooling water temperature. Shows a relief state in which the state is 75 ° C. as in FIG. 7.

Reference numeral 14 is an intake passage, 15 is a throttle valve arranged in the intake passage 14, 16 is a valve shaft, 17 is a cooling water passage provided around the upper portion of the temperature sensing member 3, and 18 is the throttle body body 1. Cooling water is sealed by an O-ring interposed between the temperature sensitive members 3.

In the above prior art, when the cooling water temperature is lower than 70 ° C., the pin 4 is retracted upward from the state shown in the drawing, the washer 11 abuts on the lower end 9a of the valve 9, and the valve 9 is acted upon by the force of the spring 8. Since the valve 9 is lifted further from the position shown in the drawing, the valve 9 is separated from the seat 6 and the opening area between them is increased.

Since the opening area increases as the cooling water temperature decreases, the amount of air supplied to the internal combustion engine through the auxiliary air passage 2 is increased. During warm-up after engine start,
The cooling water temperature gradually rises, and pin 4 moves downwards to 70
When the temperature reaches ℃, the valve 9 comes into contact with the seat 6 as shown in FIG. 5, and the opening area becomes zero. At a temperature of about 60 ° C. or higher, the upper and lower ends of the cylindrical elastic seal member 13 elastically abut on the step portion 5c of the rod 5 and the shoulder portion 9b of the valve 9, respectively.
It has been said that air leakage is prevented through the gap between the outer diameter of the rod 5 and the inner diameter of the valve 9 fitted therein.

When the temperature of the cooling water further rises, the pin 4 moves downward as shown in FIGS. 6 and 7, compresses the relief spring 10 to press the valve 9 against the seat 6 more strongly, and the washer 11 causes the valve to move. It moves away from the lower end 9a of 9 and moves downward. In the illustrated state, the cooling water temperature is 75 ° C.
Indicates the state of.

[0015]

SUMMARY OF THE INVENTION In the above conventional technique,
When the amount of compression of the cylindrical elastic body seal member 13 formed of rubber or the like in the axial direction increases, the cylindrical shape shown in FIGS. 6 and 7 cannot be maintained, and as shown in FIG.
The outer diameter is deformed into a bulging barrel at the center. Then, along with such deformation of the inner and outer diameters, the elastic body seal member 1
The upper and lower surfaces of 3 also cannot maintain the flat horizontal surfaces shown in FIGS. 6 and 7, and as shown in FIG. 8, they are deformed into a shape substantially similar to a conical surface. The contact pressure between the rod 5 and the valve 9 changes, and the sealing force decreases.

In FIG. 8, the temperature of the cooling water of the internal combustion engine is 80.
This is the state at ℃. As shown in FIG. 8, the elastic seal member 13 is deformed, and the gap between the inner diameter (inner circumference) and the outer diameter (outer circumference) of the rod 5 and the upper and lower end surfaces of the elastic seal member 13 and the step portion 5c of the rod 5 are formed. When a gap is formed between the valve 9 and the shoulder portion 9b of the valve 9, a slight amount of air leaks through the gap and is supplied to the internal combustion engine.

Therefore, from the C point at 75 ° C. shown in FIG.
During the D ′ point of 80 ° C., the air flow rate in the auxiliary air passage 2 does not become zero and changes as shown by the broken line, and not only the idle speed after warming up becomes unstable, but also the idle speed. However, there is a problem that fuel consumption is deteriorated due to increase in fuel consumption.

When the rod 5 is relieved at a temperature higher than the point B of 70 ° C. shown in FIG. 3, the washer 11 and the valve 9 are separated from each other as shown in FIG.
This is because air is leaked from the gap between the rod 5 and the valve 9 due to the above deformation of No. 3, and the degree of the leak is changed.

Furthermore, as described above, the elastic seal member 1 is used.
When 3 is compressed and deformed, the bulged outer diameter (outer circumference) contacts the inner peripheral surface 9c of the valve 9 and elastically presses it, as shown in FIG. In this case, the friction between the two blocks the smooth movement of the valve 9 and the rod 5 in the vertical direction. This also causes a problem that the idle speed after warming up becomes unstable and increases.

The valve 9 of the elastic seal member 13
When the friction parts of and are worn for a long period of time, the frictional force between them and the sliding state change, the characteristics of the air amount control device change over time, and there is a problem in terms of reliability.

Therefore, an object of the present invention is to provide an air quantity control device for an internal combustion engine which can solve the above problems.

[0022]

In order to achieve the above object, the invention according to claim 1 includes a temperature sensing member (3) for advancing and retracting a pin (4) by sensing a warm-up state of an engine by cooling water. ,
The opening area between the rod (5) pushed forward and backward by the pin (4) and slidably fitted to the rod (5) and the seat (6) according to the forward and backward movement of the rod (5) is controlled. And a relief mechanism (12) that allows the rod (5) to move independently of the valve (9) even after the engine is warmed up.
A throttle valve (15) provided in the intake passage (14), which has an elastic seal member provided between the valve (9) and the rod (5).
In the control device for controlling the air flow rate of the auxiliary air passage (2) that bypasses the valve by the valve (9), the elastic body seal members (13A, 13B) are formed into a bellows shape surrounding the outer periphery of the rod (5) and -It is characterized in that the lower end portion is provided with first and second seal portions (13a) and (13b) which come into contact with the rod (5) and the valve (9), respectively.

The invention of claim 2 is the device according to claim 1, wherein the upper surface of the first seal portion (13a) provided at the upper end portion of the elastic body seal member (13A, 13B) is flat. In addition, the rod (5) is formed with a flat surface portion (5C) which is in contact with the upper surface of the first seal portion (13a), and the second seal portion (5C) provided at the lower end portion of the elastic body seal member (13A, 13B). 13b) the lower surface is flat and the valve (9)
Is characterized in that a flat surface portion (9B) is formed in contact with the lower surface of the second seal portion (13b).

The invention of claim 3 is the apparatus according to claim 1 or 2, characterized in that the elastic seal member (13A) is made of an elastomer. A fourth aspect of the invention is the device according to the first aspect, wherein the bellows-shaped main body portion of the elastic body sealing member is formed of a metal bellows (13B), and the first and second portions are provided at the upper and lower ends thereof. Seal part (13a) (13
It is characterized in that b) is composed of an elastomer.

According to a fifth aspect of the present invention, in the apparatus according to the second aspect, the bellows-shaped main portion of the elastic seal member is formed of a metal bellows (13B), and the bellows-shaped main portion is provided at the upper and lower ends thereof. The first and second seal portions (13a) and (13b) are made of an elastomer.

[0026]

Since the elastic seal members (13A, 13B) are bellows-shaped, their diameter hardly expands when they expand and contract according to the cooling water temperature. Moreover, the elastic force in the axial direction is stable with little change with cooling water temperature.

Therefore, the elastic seal members (13A, 13A)
The outer diameter (outer circumference) of B) does not contact the inner circumference of the valve (9). Moreover, the first and second seal portions (13a) (13
b) presses the rod (5) and the valve (9) with a stable force, and maintains a good close contact state.

In the invention of claim 2, the first seal portion (1
The upper surface of 3a) is in better contact with the flat portion (5C) of the rod (5), and the lower surface of the second seal portion (13b) is in better contact with the flat portion (9A) of the valve (9). Stick with.

According to the third aspect of the invention, the bellows-shaped main body portion of the elastic body sealing member (13A) and the first and second sealing portions (1
3a) and (13b) can be integrally formed, and stable sealing performance can be obtained.

According to the inventions of claims 4 and 5, further, a long-term stable elasticity due to the metal bellows, and good and long-term stable elasticity due to the elasticity and the seal portions (13a) (13b) made of an elastomer. Sealing property can be obtained.

[0031]

1 and 2 show a first embodiment of the present invention, in which 1 is a throttle body, 2 is an auxiliary air passage, 2a is its inlet, and 2b is its outlet. Reference numeral 3 denotes a wax type temperature sensitive member, the upper part of which faces the internal combustion engine cooling water passage 17, and the pin 4 thereof moves back and forth in response to the cooling water temperature. That is, when the temperature rises, the pin 4 advances downward, and when the temperature falls, the pin 4 retracts upward.

The state shown in the figure shows when the engine has been warmed up and the temperature of the cooling water is 80 ° C., and the pin 4 has advanced to the lower limit position. Reference numeral 5 denotes a rod having an upper portion slidably fitted to the temperature sensitive member 3 and vertically moved by the lower end of the pin 4. 6 is a (valve) seat screwed to the throttle body body 1, 7 is a spring retainer that engages with the first step portion 5a of the rod 5, and 8 is a spring retainer 7.
And a compression spring interposed between the seat 6 and the seat 6, 9 is a valve that cooperates with the seat 6, and is loosely fitted to the lower portion of the rod 5,
Relief inserted between the spring retainer 7
It is constantly urged downward by the spring 10. 11
Is fitted to the lower end of the rod 5 and is caulked at the lower end of the rod 5.

Relief spring 10 and washer 11
Has a relief mechanism 12 in which the rod 5 can move up and down independently of the valve 9 even after the engine is warmed up. The relief mechanism 12 allows the pin 4 to advance downward as shown in the figure after the engine is warmed up. In this way, the temperature sensitive member 3 is protected from being damaged. In this state, the washer 1 integrated with the rod 5
1 moves downward from the lower end 9a of the valve 9.

Reference numeral 13A is a bellows-shaped elastic seal member made of an elastomer such as synthetic rubber, and thick first and second seal portions 13a and 13b are integrally formed at the upper and lower ends thereof.

Both the upper surface of the first seal portion 13a and the lower surface of the second seal portion 13b are horizontal and planar, and are formed on the second step portion which is also the lower end surface of the large diameter portion 5b of the rod 5. The horizontal flat surface portion 5C and the horizontal flat surface portion 9B formed on the bulb 9 are in close contact with each other. The sealability of these close contact portions is ensured by the respective seal portions 13a, 13b being elastically pressed against the flat surface portions 5C, 9B by the elastic force of the bellows-shaped elastic seal member 13A.

The bellows-shaped elastic seal member 13A is mounted in a state in which the seal portions 13a and 13b formed on the upper and lower ends of the rod 5 surround the rod 5 and are compressed so as to press the flat portions 5C and 9B, respectively. To be done.

Further, the inner diameters (inner circumferences) of the seal portions 13a and 13b are loosely fitted so as to fit into the rod 5 with a minute gap. A gap larger than this gap is formed between the bellows-shaped maximum outer diameter of the elastic body seal member 13A and the inner peripheral surface 9c of the valve 9. By doing so, friction between the outer periphery of the elastic seal member 13A and the inner peripheral surface 9c of the valve 9 is avoided.

In the first embodiment, the engine cooling water temperature is 4
The change in the flow rate of the air flowing through the auxiliary air passage 2 when changing from 0 ° C. to 80 ° C. is shown by the solid line in FIG. This experimental data is the value when the intake pipe negative pressure is 41.3 kPa (abs) when idling.

As is apparent from FIG. 3, even in the warmed-up state of 70 ° C. or higher and in the relief state, the auxiliary air passage 2 has a straight line connecting a point C of 75 ° C. to a point D of 80 ° C. The air flow rate is maintained at zero.

FIG. 4 shows a second embodiment of the present invention, in which the elastic seal member 13B has a bellows-shaped main portion with a metal bellows 13B.
And annular seal members 13a and 13b made of elastomer such as synthetic rubber are attached to the upper and lower ends thereof with an adhesive. In the second embodiment, the axial compression force (elasticity) of the metal bellows 13B, which is the bellows-shaped elastic body sealing member, can be easily increased as compared with the first embodiment.
The elastic body seal member 13B can also be used as a relief spring. The elastic seal member 13B (metal bellows) and the washer 11 constitute the relief mechanism 12.

Therefore, the relief spring 10 shown in FIGS. 1 and 2 can be eliminated. Therefore, the valve 9 does not need to hold the lower end of the relief spring, and the shape of the upper end of the valve 9 is accordingly simplified. As a result, it is possible to eliminate the inner peripheral surface 9c of FIGS. 1 and 2 that causes interference with the bellows-shaped outer periphery of the elastic body sealing member 13B.

In the second embodiment, the elastic body seal member 1 is used.
Since 3B is composed of a bellows-shaped metal bellows, the compression force is stable for a long period of time. In addition, since the seal member uses an elastomer such as synthetic rubber, which is convenient in terms of sealing,
Air leakage from the gap between the rod 5 and the valve 9 during relief can be stably sealed for a long period of time.

The seal members 13a and 13b are formed separately from the metal bellows 13B.
Instead of sticking to B, when the sealing members 13a and 13b are fired and sulfided, the metal bellows 13B may be integrally formed by a method such as integrally inserting. For example, if the metal bellows 13B is sandwiched by the ends of the metal bellows 13B so that the seal members 13a and 13b have a U-shaped cross section, the metal bellows and the seal portion are securely connected to each other, and vibration due to vibration during use may occur. There is an advantage that there is no danger of coming off.

[0044]

Since the air amount control device for an internal combustion engine according to the present invention is constructed as described above, the elastic sealing member is deformed into a barrel shape at the time of relief, or both end portions are deformed to improve the sealing performance. Weaknesses such as deterioration can be eliminated. Also, the elastic seal member does not deform and interfere with other parts to cause frictional force or wear.

As a result, the idle speed of the internal combustion engine after warming up becomes stable, and the increase of the idle speed is suppressed to improve the fuel efficiency. Further, long-term stability of elasticity of the elastic body sealing member is improved, and durability of the air amount control device is improved.

Further, in the case where the seal portion is formed integrally with the elastic body seal member, the manufacturing is easy, and the vibration transmitted from the internal combustion engine is absorbed by the integrally molded elastomer, and a device having excellent vibration durability is also provided. realizable.

Further, in the case where the elastic seal member is composed of the metal bellows, the relief spring (10) can be eliminated, and the range for determining the design specification is widened, and the degree of freedom in design is increased.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a first embodiment of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

FIG. 3 is a diagram showing a relationship between cooling water temperature and air flow rate.

FIG. 4 is an enlarged vertical sectional view of an essential part of a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a conventional technique.

FIG. 6 is a vertical cross-sectional view of another aspect of the prior art.

FIG. 7 is an enlarged view of part B in FIG.

FIG. 8 is a diagram for explaining the deformation of the elastic body seal member 13 in FIG.

[Explanation of symbols]

 2 Auxiliary air passage 3 Temperature sensing member 4 Pin 5 Rod 5C Flat surface portion 6 Seat 9 Valve 9B Flat surface portion 12 Relief mechanism 13A Elastic body sealing member 13B Elastic body sealing member (metal bellows) 13a, 13b Sealing portion 14 Intake passage 15 Throttle valve

Claims (5)

[Claims] 1. A temperature-sensing member that senses a warm-up state of an engine by cooling water to move a pin forward and backward, a rod that is pushed and pushed by the pin, and a rod that is slidably fitted to the rod and that moves the rod forward and backward. A valve that controls the opening area between the seat and the seat, a relief mechanism that allows the rod to move independently of the valve even after engine warm-up, and an elastic seal member that is provided between the valve and the rod, In a control device for controlling an air flow rate of an auxiliary air passage bypassing a throttle valve provided in an intake passage with a valve, an elastic body sealing member is formed into a bellows shape surrounding the outer periphery of the rod, and a rod is provided at the upper and lower ends thereof. An air quantity control device for an internal combustion engine, comprising: first and second seal portions that respectively come into contact with a valve. 2. A first member provided on an upper end portion of an elastic body sealing member.
The upper surface of the seal portion is flat, and the rod has a flat portion in contact with the upper surface of the first seal portion, and the lower surface of the second seal portion provided at the lower end portion of the elastic body seal member is flat. The air quantity control device for an internal combustion engine according to claim 1, wherein the valve is formed with a flat surface portion which is in contact with the lower surface of the second seal portion. 3. The air amount control device for an internal combustion engine according to claim 1 or 2, wherein the elastic seal member is made of an elastomer. 4. The bellows-shaped main body of the elastic seal member is made of metal bellows, and the first and second parts are provided at the upper and lower ends thereof.
The air amount control device for an internal combustion engine according to claim 1, wherein the seal portion of the above is made of an elastomer. 5. The bellows-shaped main body of the elastic seal member is made of a metal bellows, and the first and second parts are provided at the upper and lower ends thereof.
The air amount control device for an internal combustion engine according to claim 2, wherein the seal portion of the above is made of an elastomer.