JPH0814069A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a suction device for an internal combustion engine which is constituted to reduce a leakage air amount during full closing of a throttle valve. CONSTITUTION:A throttle valve 2 is arranged in an intake passage 1. A gap 4 is provided between a throttle valve 2 during full closing and the inner wall surface 11 of the intake passage 1. A coating film 5 having non-adhesion is formed on the end face of the outer periphery of a throttle valve 2 to prevent accumulation of deposit in the gap 4 and prevent firm adhesion of the throttle valve 2, whereby the gap 4 can be reduced. This constitution reduces an amount of leakage air during full closing of the throttle valve 2, and reduces fuel consumption during rotation of idle rotation. The coating film 5 is formed in such a manner that the throttle valves 2 in a stacked state are spray-coated with a coating material from an outer periphery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for supplying air to an internal combustion engine.

[0002]

2. Description of the Related Art Recently, as a situation surrounding an internal combustion engine,
Demand for fuel efficiency reduction is increasing due to legal regulations. Among these, as one of the fuel consumption reduction means at the time of idle rotation, there is a reduction of the amount of leaked air when the throttle valve that controls the amount of intake air of the internal combustion engine is fully closed.

FIG. 13 shows an example of a throttle valve provided in the intake passage of a conventional internal combustion engine. The butterfly type throttle valve 32 is rotatably installed in an intake passage 30 formed in the throttle body 20. The outer peripheral end surface of the throttle valve 32 is the inner wall surface 31 of the intake passage 30.
In order to prevent the throttle valve 32 from fully hitting, a gap 34 of about 100 μm is usually provided between the outer peripheral end surface of the throttle valve 32 and the inner wall surface 31 of the intake passage 30 when the throttle valve 32 is fully closed. Even when it is closed, some air leaks from the gap 34 to the combustion chamber side of the internal combustion engine. Conventionally, the gap 34 is narrowed to reduce the amount of leaked air when the throttle valve is fully closed to reduce fuel consumption during idle rotation. Further, in order to further reduce the amount of leaked air, after the throttle valve 32 is installed in the intake passage 30 of the throttle body 20, the inner wall surface 31 of the intake passage 30 is provided from the vicinity of the outer periphery of the throttle valve 32.
Throttle valve 3 by applying solid lubricant 35 over
It is also practiced to fill the gap 34 between the inner wall surface 31 of the intake passage 30 and the inner wall surface 31 of the intake passage 30. As the solid lubricant 35, molybdenum disulfide, which is often used as a dry film lubricant, is used.

Further, for example, as shown in FIG. 12, the throttle valve 41 comprises a disc fitting 42, an elastic body 43 fixed to the outer side of the disc fitting 42, and a ring fitting 44 fixed to the outer side of the elastic body 43. And throttle valve 41
When the valve is fully closed, the ring fitting 44 and the inner wall surface 48 of the intake passage 47
A method of closely attaching and has been proposed.

[0005]

However, in the prior art, if the gap between the throttle valve and the inner wall surface of the intake passage is made narrower than a certain amount in order to reduce the amount of leaked air, an exhaust gas recirculation device (EGR), not shown, The deposit generated in the intake system by the blow-by gas reducing device (PCV) or the like may be accumulated in this gap, and the throttle valve and the intake passage inner wall surface may stick to each other when the throttle valve is fully closed, which may prevent the throttle valve from opening. .

An object of the present invention is to provide an intake system for an internal combustion engine that reduces the amount of leaked air when the throttle valve that controls the intake air amount of the internal combustion engine is fully closed, and prevents the throttle valve from sticking due to deposits. Especially.

[0007]

In order to solve the above problems, an intake system for an internal combustion engine according to claim 1 of the present invention comprises:
An intake device for controlling an intake air amount of an internal combustion engine by opening and closing a throttle valve provided in an intake passage of an internal combustion engine, wherein at least an outer peripheral end surface of the throttle valve and a surface of the intake passage opposite to the throttle valve facing surface. It is characterized in that a coating film having non-adhesiveness is formed on one side.

According to a second aspect of the present invention, there is provided an intake system for an internal combustion engine according to the first aspect, wherein the coating film is made of a fluororesin-based coating material. Furthermore, the intake device for an internal combustion engine according to claim 3 of the present invention is the intake device for an internal combustion engine according to claim 2, characterized in that the coating film is made of a tetrafluoroethylene resin-based coating material. .

An intake system for an internal combustion engine according to claim 4 of the present invention is the intake system according to claim 1, wherein:
The coating film is made of a silicon-based coating material. Furthermore, an intake system for an internal combustion engine according to claim 5 of the present invention is the intake system according to any one of claims 1 to 4, wherein the coating film is formed by stacking a plurality of the throttle valves. It is characterized in that it is formed by spray-coating the coating material on the outer peripheral end face.

[0010]

As described above, the sticking between the throttle valve and the inner wall surface of the intake passage when the throttle valve is fully closed is mainly due to the deposit accumulated in the gap between the throttle valve and the inner wall surface of the intake passage. Therefore, the present invention is
By preventing deposits from adhering to the outer circumference of the throttle valve, sticking of the throttle valve is prevented, and the gap can be narrowed to reduce the amount of leaked air.

That is, according to the intake device for the internal combustion engine of the first aspect of the present invention, the non-adhesive coating film is formed on at least one of the outer peripheral end surface of the throttle valve and the throttle valve facing surface of the inner wall of the intake passage. Therefore, the deposit is unlikely to adhere, and the deposit is easily peeled off even when the deposit is adhered. Therefore, there is an effect that deposits are prevented from accumulating in the gap between the throttle valve and the inner wall surface of the intake passage, and the sticking of the throttle valve is prevented. Therefore, the gap between the throttle valve and the inner wall surface of the intake passage can be made narrower than in the conventional case.

According to the second aspect of the present invention, the intake device for an internal combustion engine has the effect of preventing deposits because the coating film is formed of a fluororesin-based or silicon-based coating material having high non-adhesiveness. Is big. Further, when the coating film is formed of a tetrafluoroethylene resin-based coating material as in the intake device for an internal combustion engine according to claim 3 of the present invention, the effect of preventing the adhesion becomes greater.

Further, according to the fifth aspect of the present invention, in the intake system for an internal combustion engine, the coating film is formed by spray-coating the coating material on the outer peripheral end face with a plurality of the throttle valves being superposed. Since it is formed, it is easy to form the coating film.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. (First Embodiment) A first embodiment of the present invention is shown in FIGS. As shown in FIGS. 1A and 1B, a plate-shaped throttle valve 2 is provided in an intake passage 1 having a circular cross section formed in a throttle body 20 of an internal combustion engine. The butterfly type throttle valve 2 is fixed to the valve shaft 3 by screws 13 and 14, and the valve shaft 3 is fixed to the throttle body 2 by bearings (not shown) provided at both ends of the valve shaft 3.
It is rotatably supported at 0. A gap 4 is formed between the throttle valve 2 and the inner wall surface 11 of the intake passage 1.

As shown in FIG. 2, the outer peripheral end surface 12 of the throttle valve 2 is provided with a coating film 5 made of a coating material of tetrafluoroethylene resin. As shown in FIG. 3, the coating film 5 is provided in the intake passage 1
A large number of throttle valves 2 before being mounted on the inner valve shaft 3
Are piled up into a cylindrical shape, and 1 is attached to the outer peripheral side surface of this cylindrical shape.
It is formed by spraying a coating material to a thickness of 0 ± 5 μm.

Since the coating film 5 made of ethylene tetrafluoride resin formed on the outer peripheral end face 12 of the throttle valve 2 has a high non-adhesive property, the deposit is prevented from adhering to the throttle valve 2. Also, the deposited deposit is easily separated from the throttle valve 2. Therefore, the gap 4
Throttle valve 2 due to deposit deposits
Therefore, there is an effect that the gap 4 can be made as small as possible to reduce the amount of leaked air.

Since the coating film 5 is formed before the throttle valve 2 is assembled to the valve shaft 3 in the intake passage 1, molybdenum disulfide or the like is applied after the throttle valve is assembled to the intake passage. The workability is good and the cost can be reduced as compared with the above method. Further, since the coating film 5 is formed in a state where a large number of throttle valves 2 are stacked, it is possible to form the coating film 5 on the outer peripheral end surface 12 of a large number of throttle valves 2 at a time, improving workability and reducing cost. Can be achieved.

(Second Embodiment) FIGS. 4 to 9 show variations of the second embodiment of the present invention. This is an example in which the shape of the outer peripheral portion of the throttle valve is devised. FIG. 4 shows an example in which the outer peripheral portion of the throttle valve 2 is cut into an acute angle shape composed of two slopes 21 and 22.

FIG. 5 shows an example in which the tip of an acute angle is formed on the round surface 23 in the example shown in FIG. FIG. 6 shows an example in which a flat surface 25 is formed by chamfering the outer peripheral portion of the throttle valve 2. FIG. 7 shows an example in which the thin plate portion 26 is formed by cutting the outer peripheral portion of the throttle valve 2 on the side opposite to the intake air inflow direction so that the outer peripheral portion has a thickness of about half the central portion.

FIG. 8 shows an example in which a thin plate portion 27 is formed by cutting the outer peripheral portion of the throttle valve 2 on the intake inflow direction side so that the outer peripheral portion has a thickness of about half the central portion. FIG. 9 shows that the outer peripheral portions of the throttle valve 2 on the intake inflow side and the anti-intake inflow side are each cut by about one third of the thickness of the central portion, and the thickness of the outer peripheral portion is about a third of the central portion. This is an example in which the portion 28 is formed.

4-9, the coating film 5 is
Similar to the first embodiment, a large number of throttle valves 2 before being assembled to the valve shaft 3 in the intake passage 1 are stacked into a columnar shape,
This cylinder is formed by spray coating a tetrafluoroethylene resin-based coating material with a thickness of 10 ± 5 μm from the side surface. According to the second embodiment of the present invention, the effect of preventing the sticking of the throttle valve 2 is further enhanced by reducing the size of the flat surface portion of the intake passage 1 that faces the inner wall surface 11.

(Third Embodiment) A third embodiment of the present invention is shown in FIG.
0 is shown. The third embodiment is an example in which a coating film is also formed on the outer peripheral portion on the side opposite to the intake air intake in the second embodiment shown in FIG. The throttle valve 2 is cut into the intake air inflow direction side and the thickness of the outer peripheral part is about half of the central part. The throttle valves 2 are stacked in a cylindrical shape, and the coating material is spray-applied from the side surface of the cylinder. Of the portion facing the inner wall surface 11 of the intake passage 1 and a flat surface 5 formed by cutting the thickness.
The coating film 5 is formed on the layers 2, 53. Here, after the throttle valves 2 are separated again one by one, the coating material is applied to the outer peripheral portion 54 of the throttle valve 2 on the side opposite to the intake air intake side.

As a result, the entire outer peripheral portion of the throttle valve 2 can be covered with the coating film 5, and the deposit can be prevented from sticking to the side opposite to the intake air intake side of the throttle valve 2 due to turbulence in the intake passage. There is. (Fourth Embodiment) FIG. 11 shows a fourth embodiment of the present invention. The fourth embodiment is an example in which the coating film is formed on the inner wall surface of the intake passage instead of being formed on the outer peripheral end surface of the throttle valve in the first embodiment of the present invention.

The coating film 5 is formed by coating the inner wall surface 11 of the intake passage 1 with a tetrafluoroethylene resin-based coating material of 10 ±.
It is formed by coating to a thickness of 5 μm. The position where the coating film 5 is formed is centered on the position on the inner wall surface 11 of the intake passage 1 that faces the outer peripheral portion of the throttle valve 2 when the throttle valve 2 is fully closed, the coating length of the coating film is L, and the throttle valve is When the diameter of 2 is d, L ≧ d
The range is / 2.

As a result, the deposit is prevented from adhering to the inner wall surface 11 of the intake passage 1, and the deposited deposit is easily separated from the inner wall surface 11. Therefore, the deposit of the deposit in the gap 4 causes the throttle valve 2 to move. Sticking is prevented. Therefore, similarly to the first embodiment, there is an effect that the amount of leaking air can be reduced by making the gap 4 as small as possible.

In the present invention, the coating film may be formed on both the outer peripheral end surface of the throttle valve and the inner wall surface of the intake passage. By forming the coating film on both the outer peripheral end surface of the throttle valve and the inner wall surface of the intake passage, it is possible to further enhance the effect of preventing deposit adhesion. (Fifth Embodiment) In the fifth embodiment of the present invention, similarly to the first embodiment, a coating film is formed on the outer peripheral end surface of the throttle valve, and after the assembly of the coating film on the valve shaft in the intake passage, Molybdenum disulfide as a solid lubricant was applied from the outer periphery to the inner wall surface of the intake passage.

According to the fifth embodiment of the present invention, the solid lubricant is used to fill the gap, which can be made narrower than before by forming the coating film, without impairing the effect of preventing the throttle valve from sticking. The amount of leaked air when the throttle valve is fully closed can be further reduced. (Sixth Embodiment) In a sixth embodiment of the present invention, a coating film is formed by using a silicon-based coating material instead of the tetrafluoroethylene resin-based coating material used in the first embodiment.

According to the sixth embodiment of the present invention, due to the non-adhesiveness of the silicon-based coating film, the deposit is prevented from adhering to the inner wall surface of the intake passage, and the deposited deposit is also peeled off from the inner wall surface. It will be easier. For this reason,
It is possible to prevent the throttle valve from sticking due to deposits accumulated in the gap between the throttle valve and the inner wall surface of the intake passage. Therefore, similarly to the first embodiment, there is an effect that the gap can be made as small as possible to reduce the amount of leaked air.

[Brief description of drawings]

FIG. 1 shows an intake system for an internal combustion engine according to a first embodiment of the present invention, (A) is a cross-sectional view, and (B) is its BB.
It is a line sectional view.

FIG. 2 is an enlarged view of a portion II shown in FIG.

FIG. 3 is a cross-sectional view showing a method of forming a coating film according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing an example of the shape of the outer peripheral portion of a throttle valve according to the second embodiment of the present invention.

FIG. 5 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the second embodiment of the present invention.

FIG. 6 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the second embodiment of the present invention.

FIG. 7 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the second embodiment of the present invention.

FIG. 8 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the second embodiment of the present invention.

FIG. 9 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the second embodiment of the present invention.

FIG. 10 is a sectional view showing an example of the shape of the outer peripheral portion of the throttle valve according to the third embodiment of the present invention.

FIG. 11 is a vertical sectional view showing an intake system for an internal combustion engine according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing an example of a conventional intake device for an internal combustion engine, (A) is a plan view of a throttle valve, and (B) is a longitudinal sectional view thereof.

13A and 13B are diagrams showing an example of a conventional intake device for an internal combustion engine, FIG. 13A being a cross-sectional view and FIG. 13B being a cross-sectional view taken along the line BB.

[Explanation of symbols]

 1 Intake passage 2 Throttle valve 3 Valve shaft 4 Gap 5 Coating film 11 Inner wall surface 12 Outer peripheral end surface

Claims (5)

[Claims] 1. An intake device for controlling an intake air amount of an internal combustion engine by opening and closing a throttle valve provided in an intake passage of the internal combustion engine, wherein the throttle valve on an outer peripheral end surface of the throttle valve and an inner wall of the intake passage. An intake device for an internal combustion engine, comprising a non-adhesive coating film formed on at least one of the facing surfaces. 2. The intake system for an internal combustion engine according to claim 1, wherein the coating film is made of a fluororesin-based coating material. 3. The intake system for an internal combustion engine according to claim 2, wherein the coating film is made of a tetrafluoroethylene resin-based coating material. 4. The intake system for an internal combustion engine according to claim 1, wherein the coating film is made of a silicon-based coating material. 5. The coating film is formed by spray-applying the coating material on the outer peripheral end face in a state where a plurality of the throttle valves are overlapped with each other. An intake system for an internal combustion engine according to the above item.