JPH0645661Y2 - Air valve for internal combustion engine - Google Patents

Description

The present invention relates to an air valve for an internal combustion engine, and more particularly to an air valve suitable for use in an air system of a fuel injection device.

(Prior Art) The fuel injection device is provided with an air valve for overcoming the rotational frictional force of the engine during the warm-up operation after starting the engine and for supplying the air amount necessary for early warm-up. .
This air valve opens a bypass passage bypassing the throttle valve to supply air to the engine in order to properly warm up the engine when cold, and automatically shuts off the bypass passage after the engine warms up.

A conventional air valve is, for example, as disclosed in JP-A-53-38818, a temperature sensor disposed in an engine cooling water passage and a valve port formed in the middle of a bypass passage bypassing a throttle valve. And a valve element which is operated by the temperature sensing element and variably controls the flow passage area of the valve opening.

A needle valve with a tapered tip is used for this valve body, and the needle valve is pushed into the valve opening by the temperature sensing element that expands and contracts in accordance with the temperature of the engine cooling water, and the flow at the valve opening flows. The road area is variably controlled, and the air amount according to the engine cooling water temperature is supplied to the engine through the bypass passage.

(Problems to be solved by the invention) By the way, sludge, carbon, and the like adhere to the valve body due to blowback of the engine over a long period of use, but the amount of adhesion increases in proportion to the contact area with air.

In the conventional air valve that uses a needle valve for the valve body, the entire circumference of the valve body becomes the contact surface with air, so the amount of carbon and other substances deposited increases, and the flow passage area of the valve opening gradually increases over time. As a result, the amount of air is narrowed, and as a result, the amount of air cannot be accurately controlled according to the temperature of the engine cooling water.

(Means for Solving the Problems) In view of the above problems, an object of the present invention is to provide an air valve that reduces the adhesion of carbon and the like and enables accurate air amount control over a long period of time.

The structure of the present invention which meets such an object is a valve opening formed in the middle of a temperature sensing body (11) arranged in an engine cooling water passage (6) and a bypass passage (4) bypassing a throttle valve (3). (16) and a valve body (12) slidably fitted in the valve mouth (16) slidably and actuated by the temperature sensing element to variably control the flow passage area of the valve mouth, In an air valve for an internal combustion engine that controls the amount of air flowing through a bypass passage in accordance with the above, a groove (12
c) is formed along the axial direction, a temperature sensitive plate (12e) that is deformed by a change in ambient temperature is attached to the groove (12c), and the flow path of the valve opening is set according to the temperature of the air flowing through the bypass passage. It is characterized in that the cross-sectional area is variably controlled.

(Operation) According to the above configuration, the valve body is tightly fitted to the valve opening,
Only the groove provided with the temperature sensitive plate serves as the flow path of the air flowing through the valve opening. Therefore, the contact area of the valve body with air becomes small,
The amount of carbon etc. deposited is reduced. Therefore, the amount of air flowing through the bypass passage controlled according to the temperature of the engine cooling water is corrected by the action of the temperature sensing plate (12e).

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 is a throttle body, and an intake passage 2 is provided inside.
And a throttle valve 3 is arranged in the intake passage 2. Further, the throttle body 1 is provided with a bypass passage 4 for bypassing the throttle valve 3 to supply air to an engine (not shown), a valve chamber 5 and a cooling water passage 6, and an air valve 10 is provided in the valve chamber 5. It is arranged.

The air valve 10 includes a temperature sensitive body 11 filled with thermowax that expands and contracts according to the ambient temperature, and a valve body 12 operated by the temperature sensitive body 11. The temperature sensitive body 11 is provided in the cooling water passage 6. The cooling water passage 6 and the valve chamber 5 are partitioned by a partition wall 7 so that the cooling water does not enter the valve chamber 5. Also the temperature sensor 11
The valve body 12 and the valve body 12 are connected to each other through a rod 13 that expands and contracts due to expansion and contraction of thermowax, and a spring 14 mounted between the rod 13 and the valve body 12.

As shown in FIG. 2, the valve body 12 is formed with a small-diameter cylindrical portion 12a and a large-diameter cylindrical portion 12b connected to the small-diameter cylindrical portion 12a.
A groove 12c is formed on the outer peripheral surface of the groove 12c parallel to the axial direction of the small-diameter cylindrical portion 12a, the groove 12c opening to the tip surface and having a cross-sectional area that decreases as the distance from the tip surface increases. A temperature sensitive plate 12e made of bimetal or the like is attached so as to be reversible.

On the other hand, a valve seat 15 is fixed in the middle of the bypass passage 4, and the valve seat 15 forms a valve port 16.

The outer diameter of the small-diameter cylindrical portion 12a is set so as to be slidably and tightly fitted in the valve opening 16, so that the groove 12c is formed in the valve opening 16
It becomes the flow path of the air.

Reference numeral 17 denotes a spring 17 mounted between the valve body 12 and the throttle body 1 for urging the valve body 12 away from the valve opening 16. The spring load of this spring 17 is smaller than that of the spring 14. It is set.

The embodiment of the present invention is configured as described above, and when the engine cooling water temperature is low, the rod 13 is contracted, and the small diameter cylindrical portion 12a formed in the valve body 12 has a small amount of protrusion into the valve opening 16. Therefore, the cross-sectional area of the groove 12c, which serves as an air flow path, is set to be large, and the amount of air required for warming the air supply is increased from the throttle valve 3 upstream side of the intake passage 2 to the downstream side bypass passage 4, the groove 12c Is supplied to the flow engine via.

When the temperature of the engine cooling water rises, the temperature sensitive body 11 is warmed and the thermo wax inside expands, the rod 13 extends and the valve body expands.
12 moves to the left in the figure against the urging force of the spring 17, and the amount of plunge of the small-diameter cylindrical portion 12a increases. Therefore, the cross-sectional area of the groove 12c that serves as a flow path decreases, and the amount of air supplied to the engine through the bypass passage 4 decreases as the cooling water temperature rises.

In this case, the temperature sensitive plate 12e is in close contact with the bottom surface as shown in FIG. 2a in the summer when the temperature of the air flowing through the bypass passage 4 is high, but as shown in FIG. 3 in the winter when the air temperature is low. Deforms and warps back from the bottom. Therefore, the cross-sectional area of the flow passage is reduced even if the amount of protrusion of the small diameter cylindrical portion 12a is the same as in the state shown in FIG. 2a.

Therefore, according to the embodiment of the present invention, the air amount controlled based on the engine cooling water temperature is corrected according to the air temperature by the action of the temperature sensing plate 12e. That is, even if the cooling water temperature is the same, when the air temperature is high and the air density is low, the flow passage cross-sectional area increases and the air amount increases, and when the air temperature is low and the air density is high, the flow passage cross-sectional area decreases. The amount of air also decreases.
As a result, the mass flow rate of air required for warm-up operation is supplied to the engine.

(Effect of the Invention) According to the present invention, the valve body is provided with the groove having the temperature sensitive plate which is deformed by the change of the ambient temperature on the bottom surface, and this groove serves as a flow path of the air flowing through the valve opening. The contact area with air can be reduced. Therefore, the amount of carbon or the like deposited due to engine blowback is reduced, and accurate and stable air amount control can be performed for a long period of time.

Particularly, in this invention, the air amount controlled based on the engine cooling water temperature is corrected according to the air temperature by the action of the temperature sensing plate 12e. That is, even if the cooling water temperature is the same, when the air temperature is high and the air density is low, the flow passage cross-sectional area increases and the air amount increases, and when the air temperature is low and the air density is high, the flow passage cross-sectional area decreases. The amount of air also decreases. As a result, the mass flow rate of air required for warm-up operation is supplied to the engine.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIGS. 2a and 2b are enlarged sectional views of an essential part of the present invention, and FIG. 3 is an operation explanatory view of a temperature sensing plate. 3 ... Throttle valve, 4 ... Bypass passage, 6 ... Cooling water passage, 10 ... Air valve, 11 ... Temperature sensor, 12 ... Valve body, 12c ... Groove, 1
2e ... Temperature plate, 16 ... Valve mouth.

Claims (1)

[Scope of utility model registration request] 1. A temperature sensor (11) disposed in an engine cooling water passage (6), and a valve port (16) formed in the middle of a bypass passage (4) bypassing a throttle valve (3). And a valve body (12) which is slidably tightly fitted in the valve opening (16) and is operated by the temperature sensing element to variably control the flow passage area of the valve opening, and the bypass passage according to the temperature of the engine cooling water. In an air valve for an internal combustion engine for controlling the amount of air flowing through, (a) a groove (12c) opening to the tip end surface of the valve body is formed in the valve body along the axial direction, and (b) the groove (12c). An air valve for an internal combustion engine, characterized in that a temperature sensitive plate (12e) which is deformed due to a change in ambient temperature is attached to the.