JPH0617965A - Flow control valve for recirculating exhaust gas - Google Patents

Abstract

PURPOSE:To provide a flow control valve of exhaust gas recirculation equipment which can restrain a large amount of NOx from being produced when an engine is accelerated by controlling application of electric power to a solenoid coil divided into three parts, and controlling the valve opening stepwise using an electromotive force. CONSTITUTION:A plunger 26 having a valve element 12 is inserted into the chamber 4 of a casing 6, and a spring (A) 27 and a tube (A)23 having an attracting element (A)28 at its end portion are disposed above the plunger 26 and a coil (A)33 and a housing (A)34 are provided outside the tube (A)23. Similarly, a spring (B)29 and a tube (B)24 having an attracting element (B) 30 secured thereto are provided thereover with a housing (B)36 stacked on a coil (B)35, and thereover a spring (C)31, a tube (C)25 having an attracting element (C)32 secured thereto, a coil (C)27 and a housing (C)38 are stacked atop one another.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate control valve capable of controlling valve opening in multiple stages by controlling energization of three electromagnetic coils, and particularly to exhaust gas from an exhaust system of an automobile engine to an intake system. Part of the gas is refluxed, and nitrogen oxides NO _x
The present invention relates to a flow rate control valve for exhaust gas recirculation for suppressing the generation of.

[0002]

2. Description of the Related Art Conventionally, a diaphragm type flow control valve has been used as a flow control valve for recirculating exhaust gas of an automobile engine. FIG. 2 is a vertical cross-sectional side view showing the structure of this exhaust gas recirculation system, in which the flow control valve 1 includes a casing 6 having a valve seat 5 provided below a chamber 4 which connects the inflow port 2 and the outflow port 3. , A bush 7 mounted above the chamber 4, a diaphragm 9 contained in a case 8, a spring 10 for urging the diaphragm 9 downward, and a shaft 11 mounted on the diaphragm 9 It is composed of a valve body 12 fixed to the tip.

The flow control valve 1 has an inlet 2
Is connected to the exhaust manifold 14 side, and the outlet 3 is connected to the intake manifold 15 side. Further, the modulating valve 17 is for controlling the negative pressure in the vicinity of the throttle valve 16 of the intake manifold 15, and the modulating valve 17 is located in front of the throttle valve 16 of the intake manifold by a conduit 17a. A conduit 17b is connected to the exhaust manifold 14 side at a position behind the throttle valve 16 by a conduit 17c. Also,
The conduit 17b is also connected to the chamber 13 of the flow control valve 1. Then, the negative pressure in the chamber 13 and the equilibrium of the spring 10 cause the valve body 12 at the tip of the shaft 11 attached to the diaphragm 9 to move up and down, thereby suppressing the amount of exhaust gas recirculated to the intake system. It was

Although not shown, a step motor type EGR valve (for example, see Japanese Patent Laid-Open No. 3-118373) is sometimes used as a flow rate control valve for recirculating exhaust gas of an automobile engine.

[0006]

The modulating valve 17 in the exhaust gas recirculation device has a fluid pressure before and after the throttle valve 16 of the intake manifold 15 and the exhaust manifold 1.
4 operates by the pressure of the exhaust gas and changes the clearance between the valve of the modulating valve 17 and the valve opening, whereby the amount of intake air in the atmosphere is controlled and the conduit 17
It is sucked from b into the vicinity of the throttle valve 16 of the intake manifold 15.

On the other hand, the flow control valve 1 has the above-mentioned conduit 17 in which the inside of the chamber 13 above the diaphragm 9 is in a negative pressure state.
Since it is communicated with b, the diaphragm 9 is lifted up in response to this negative pressure, the valve body 12 fixed to the lower end of the shaft 11 is opened, and a part of the exhaust gas is returned to the intake manifold 15. It is like this. But NO _X
At the time of engine acceleration where the amount of
Since 6 is fully opened, the negative pressure in the chamber 13 is
The amount of lift of the valve element 12 becomes extremely small and becomes small. Therefore, there is a problem that the amount of exhaust gas recirculated from the exhaust manifold 14 can not be achieved an effective reduction of the NO _X insufficient significantly.

Further, the latter step motor type EGR valve has a feature that exhaust gas can be sufficiently recirculated to the intake manifold 15 even during engine acceleration when the amount of NO _x generated increases. However, there is a problem that the EGR valve itself becomes extremely expensive.

[0009]

The present invention has been made in order to solve the above problems, and detects the acceleration state of the engine by an O ₂ sensor 40 mounted in the exhaust manifold 14, By controlling the energization to the electromagnetic coil that divides the sensed signal into three and controlling the valve opening stepwise by electromagnetic force, the proper amount of recirculated exhaust gas can be obtained in the steady operation in the low and medium load range. The purpose of the invention is to provide a flow control valve for an exhaust gas recirculation device that secures the same amount of exhaust gas as required to suppress the generation of a large amount of NO _x when accelerating the engine, in addition to securing the same as the product. To do.

That is, as shown in FIG. 1, a flow control valve for exhaust gas recirculation according to the present invention has a cylindrical body 21 with its central portion facing downward on the upper surface of a casing 6 having a valve seat 5 below the chamber 4. The plate 22 formed on the
Inside the chamber 4, the valve body 1 is provided at the lower end of the shaft 11.
2 is provided, and a plunger 26, which is airtightly fixed by a bellows 20 between the lower end of the cylindrical body 21 of the plate 22 and the outer diameter portion of the shaft 11, is provided.
A tube (A) 23, which is formed by fixing a flange portion of a suction element (A) 28 to a tip portion of the tube (A) 23 via a spring (A) 27, is fitted to the plunger 26, and The plate (22) is placed upright on the center of the plate (22), and the coil (A) 33 and the housing (A) are provided on the plate (22) outside the tube (A), and the suction element (A) ) 28 above the tube (A) 23 via a spring (B) 29, a tube (B) 24 formed by fixing a flange portion of a suction element (B) 30 to the tip end of the tube (A) 23.
The tube (B) 2
4, a coil (B) 35 and a housing (B) 36 are stacked and provided above the coil (A) 33, and a spring (C) 31 is provided above the suction element (B) 30.
The tube (C) 25 having the flange portion of the suction element (C) 32 fixedly attached to the tip end thereof via the tube (B).
24, the coil (C) 37 and the housing (C) 38 are stacked and provided outside the tube and above the coil (B) 35. (C) 32 is fixed with a bolt 39.

[0011]

The flow control valve for exhaust gas recirculation of the present invention is O ₂
The signal sensed by the sensor 40 controls the energization to the electromagnetic coil divided into three parts, and the opening degree of the control valve is controlled in three steps as necessary, so that the exhaust gas in the exhaust manifold 14 is sucked into the intake manifold 15 It can be refluxed in.

[0012]

Embodiments of the invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing a flow rate control valve of an exhaust gas recirculation system according to the present invention. The flow rate control valve 19 includes a casing 6, a plate 22, a plunger 26 having a valve element at a lower portion, tubes 23, 24 and 25 to which three suction elements 28, 30, and 32 are fixed, and three coils. Three
3, 35, 37 and three housings 34, 36, 3
8 and. Like the conventional product, the casing 6 has a valve seat 5 provided below a chamber 4 which connects the inflow port 2 and the outflow port 3 with each other. A plate 22 is fixed to the upper surface of the casing 6 and has a cylindrical body 21 with the central portion facing downward.

The plunger 26 is housed in the chamber 4 and is vertically slidable in a tube (A) 23, which will be described later. The lower end of the plunger 26 has a shaft 11 interposed therebetween. A valve body 12 that comes into contact with and separates from the valve seat 5 is fixed to the tip of the lever by press fitting or the like. The bellows 20 is for preventing the plunger 26 from coming into contact with exhaust gas. The upper end of the bellows 20 is the lower end of the tubular body 21 of the plate 22, and the lower end of the bellows 20 is the shaft 11. It is airtightly fixed by welding to the outer diameter part.

The tube (A) 23 has a flange portion of a suction element (A) 28 fixedly attached to the tip thereof, and the tube (A) 23 has a spring (A) mounted above the plunger 26. After being placed, it is fitted on the outside of the plunger 26, and is placed upright on the center of the plate 22. Further, the coil (A) 33 and the housing (A) 34 are provided corresponding to the plunger 26, and these are provided on the plate 22 outside the tube (A) 23 and are not shown. The housing (A) 34 and the plate 22 are fixed by caulking.

The tube (B) 24 has a flange portion of a suction element (B) 30 fixed to the tip thereof, and the tube (B) 24 is provided with a spring (above the suction element (A) 28). B) After placing 29, the tube (A)
The tube (A) 23 is fitted to the outside of the tube 23 so that the tube (A) 23 can slide up and down in the tube (B) 24. In addition, the coil (B) 35 and the housing (B) 36
Is provided corresponding to the suction element (B) 30, and these are provided outside the tube (B) 24 and above the coil (A) 33. The lower end of the housing (B) 36 is caulked and fixed to the plate 22 as described above.

The tube (C) 25 has a flange portion of a suction element (C) 32 fixed to the tip thereof, and the tube (C) 32 is provided with a spring (above the suction element (B) 30). C) After placing 31 the tube (B)
The tube (C) 24 is fitted to the outside of the tube 24 so that the tube (B) 24 can slide up and down. In addition, the coil (C) 37 and the housing (C) 38
Corresponds to the suction element (B) 30 and the tube (C) 25
The housing (C) 38 and the suction element (C) 32 are fixed to each other by bolts 39.

The O ₂ sensor 40 is for detecting the acceleration state of the engine, is attached inside the exhaust manifold 14, and is divided into three electromagnetic coils by the signal sensed by the O ₂ sensor 40. The energization of can be controlled.

[0018]

Next, the operation of the present invention will be described in detail with reference to the drawings. When the coil (A) 33 is energized from the valve closed state of FIG. 1, the plunger 26 resists the force of the bellows 20 and the spring (A) 27, and is applied to the lower end surface of the suction element (A) 28. The valve body 12 is adsorbed and the valve body 12 is slightly opened, and the exhaust gas in the exhaust manifold is returned to the intake manifold through the inflow port 2 and the outflow port 3.

When the coil (A) 33 is de-energized and the coil (B) 35 is energized, the plunger 26 is attracted to the suction element (A) 28 and the suction element (A) 28 is sucked. (B) The valve body 12 is further opened by being adsorbed on the lower end surface of the valve 30. Similarly, the coil (B) 35 is turned off,
When the coil (C) 37 is energized, the plunger 26 and the suction element (A) are attracted to the suction element (B) 30, and the suction element (B) 30 is attracted to the lower end surface of the suction element (C) 37. Then, the valve body 12 is further opened.

In the above embodiment, the case where the coil is divided into three has been described, but it goes without saying that the valve opening can be finely controlled by further increasing the number of coils in the same combination.

[0021]

According to the flow control valve of the present invention, the acceleration state of the engine is detected by the O ₂ sensor 40 mounted in the exhaust manifold 14, and the sensed signal is energized to the electromagnetic coil divided into three. By controlling, the opening of the valve opening is forcibly controlled by electromagnetic force,
Since it does not depend on the negative pressure in the vicinity of the throttle valve 16 of the intake manifold 15 as in the conventional case, it is possible to suppress a large amount of NO _X generated during engine acceleration.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a flow rate control valve of an exhaust gas recirculation device according to the present invention.

FIG. 2 is a vertical sectional side view showing a configuration of a conventional exhaust gas recirculation device.

[Explanation of symbols]

1 flow control valve, 2 inflow port, 3 outflow port,
4 chambers, 5 valve seats, 6 casings,
7 bush, 8 case, 9 diaphragm,
10 springs, 11 shafts, 12 valve bodies, 13 chambers, 14 exhaust manifolds,
15 intake manifold, 16 throttle valve, 17
Modulating valve, 17a conduit, 17b
Conduit, 17c conduit, 20 bellows,
21 tube, 22 plate, 23 tube (A), 24 tube (B), 25 tube (C), 26 plunger, 27 spring (A), 28 suction element (A), 29 spring,
30 suction element (B), 31 spring (C),
32 suction element (C), 33 coil (A), 34 housing (A), 35 coil (B), 36 housing (B), 37 coil (C), 38 housing (C), 39 bolt 39.

Claims (1)

[Claims] 1. A plate 22 having a central portion formed in a downward cylindrical body 21 is fixedly provided on an upper surface of a casing 6 having a valve seat 5 provided below the chamber 4, and a shaft is provided in the chamber 4. 11 is provided with a valve body 12 at a lower end portion thereof, and a plunger 26 is provided, which is airtightly fixed by a bellows 20 between a lower end portion of the cylindrical body 21 of the plate 22 and an outer diameter portion of the shaft 11, and above the plunger 26. Has
A suction element (A) is attached to the tip through the spring (A) 27.
A tube (A) 23 formed by fixing 28 flanges
Is mounted on the plate 22 outside the tube (A) 23 so that the coil (A) is fitted to the plunger 26 and placed upright in the center of the plate 22.
33 and a housing (A) 34 are provided, and the suction element (A) is provided.
Above the pipe 28, a tube (B) 24, which is formed by fixing a flange portion of a suction element (B) 30 to a tip end portion thereof via a spring (B) 29, is fitted with the tube (A) 23, and is vertically moved. Is provided slidably on the outside of the tube (B) 24 and above the coil (A) 33.
5 and the housing (B) 36 are stacked, and a flange portion of the suction element (C) 32 is fixed to the tip portion above the suction element (B) 30 via a spring (C) 31. A tube (C) 25 is provided so as to be fitted with the tube (B) 24, and a coil (C) 37 and a housing (C) 38 are stacked outside the tube and above the coil (B) 35. And the housing (C) 38
A flow control valve for exhaust gas recirculation, characterized in that the suction element (C) 32 and the suction element (C) 32 are fixed by a bolt 39.