JPH07301131A - Electromagnetic valve for exhaust brake - Google Patents

Abstract

PURPOSE:To improve responsiveness during de-energization of an actuator and to effectively suppress the generation of black smoke when an exhaust brake device is released from operation by providing a valve member to open and close an opening in wide cross section through which first and second chambers are intercommunicated separately from a valve member to control intercommunication of passages on the input side and the output side. CONSTITUTION:When a vehicle is in a engine brake running state and an electromagnetic valve 28 is energized, an armature 46 is displaced upward against the force of a valve spring 64. Through upward movement of a second valve member 48 through a valve shaft 50, the second opening 68 of a first valve member 70 is closed and the first valve member 70 is pushed upward to close a large first opening 66. Further, through upward movement of the second valve member 48, a passage 52 on the input side is communicated with a passage 54 on the outlet side. This communication feeds compressed air from a compressed air source to an actuator to close an exhaust brake valve. Thereafter, when the electromagnetic valve 28 is de-energized, through energization of a resilient member 72, the first opening 66 is opened and compressed air in the actuator is instantly exhausted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust brake solenoid valve for controlling an actuator of an exhaust brake device provided in an exhaust system of an engine such as a truck.

[0002]

2. Description of the Related Art A conceptual structure of an exhaust brake device provided in a conventional truck will be described with reference to FIG. In the figure, reference numeral 10 is an exhaust pipe of a diesel engine (not shown) mounted on a truck, 12 is an exhaust brake valve which is a butter fly valve provided in the exhaust pipe 10, and 14 is one end of a valve shaft 16 of the exhaust brake valve. A valve opening / closing rod to which is fixed, and 18 is an actuator composed of an air cylinder device for controlling opening / closing of the exhaust brake valve 12 via the valve opening / closing rod 14.

The actuator 18 is a cylinder 20.
And a piston 22 slidably fitted in the cylinder
And a spring 26 that constantly elastically biases the piston downward in the drawing, that is, in the direction of opening the exhaust brake valve 12 via the piston shaft 24 and the valve opening / closing rod 14.
At the lower end of the cylinder 20, there is provided a compressed air inlet 32 connected to a compressed air source 30 via a three-way solenoid valve 28. The electromagnetic valve 28 includes a clutch switch 34 that is closed by releasing the clutch pedal of the vehicle, an accelerator switch 36 that is closed by releasing the accelerator pedal, and a vehicle driver braking the exhaust brake device. The opening / closing is controlled by an urging circuit in which an exhaust brake switch 38 and a vehicle-mounted power source 40 which are closed manually when an effect is desired are connected in series.

As the solenoid valve 28, conventionally, a valve device as shown in the schematic sectional views of FIGS. 5 and 6 has been widely used. In the figure, reference numeral 42 is a valve casing, 44 is a solenoid housed in the valve casing 42, 46 is an armature driven by the solenoid 44, 48 is a valve member connected to the armature 46 via a valve shaft 50, 5
2 is an input passage provided in the valve casing 42 and connected to the compressed air source 30; 54 is the valve casing 42;
An output side passage provided inside the actuator 18, that is, connected to the compressed air inlet 32 of the air cylinder device;
Is a first chamber or a valve chamber which communicates with the input side passage 52 and the output side passage 54 and in which the valve member 48 is disposed, and 58 is an armature 46 slidable in the axial direction of the valve shaft 50. And the valve shaft 5 with a small gap.
A second chamber or an armature chamber communicating with the first chamber 56 through a ventilation hole 60 through which 0 is inserted, and 62 is a valve casing 4
2 is an atmosphere opening passage provided in 2 for communicating the second chamber 58 with the outside air, and 64 is a valve spring for constantly pushing the armature 46 downward, that is, the valve member 48 in a direction of closing the input side passage 52. .

In the conventional exhaust brake device described above, during normal traveling of a vehicle such as a truck, the driver desires the braking effect of the exhaust brake device and manually operates the exhaust brake switch 38.
, The solenoid valve 28 is deenergized because at least one of the clutch switch 34 and the accelerator switch 38 is open. When the electromagnetic valve 28 is deenergized, as shown in FIG. 5, the valve spring 64 presses the valve member 48 against the sealing surface of the first chamber 56 to close the input side passage 52 and the output side. The passage 54 communicates with the second chamber 58 through a small gap between the vent hole 60 and the valve shaft 50, and further communicates with the outside air through the atmosphere opening passage 62.

Therefore, the compressed air inlet 32 of the actuator 18 communicates with the atmosphere, and the return spring 26
As a result, the piston 22 is held in the rest position or the inoperative position, and the exhaust brake valve 12 is held in the fully open position shown in FIG. 4 via the piston shaft 24 and the valve opening / closing rod 14. Therefore, the exhaust pipe 10 provides a sufficient exhaust passage area and the engine operates normally.

Next, when the vehicle is in the engine brake running state, the clutch switch 34 and the accelerator switch 3 are operated.
Since all 6 are closed, if the driver previously closes the exhaust brake switch 38 in order to obtain the braking effect of the exhaust brake device, the solenoid 44 of the solenoid valve 28 is energized and the armature 46 is As shown in FIG. 6, it is displaced upward. Due to the upward displacement of the armature 46, the valve member 48 moves upward via the valve shaft 50 to connect the input-side passage 52 and the output-side passage 54 and close the vent hole 60 through which the valve shaft 50 is inserted. . As a result, the compressed air in the compressed air source 30 is supplied to the actuator 18 from the input side passage 52, the first chamber 56 and the output side passage 54 through the upstream side pressure passage and the downstream side pressure passage. The return spring 26 is compressed by the pressure of the compressed air supplied from the compressed air inlet 32 of the actuator 18 to the piston lower chamber of the cylinder 20, and the piston 22 moves upward, and the exhaust brake is performed via the piston shaft 24 and the valve opening / closing rod 14. The valve 12 is driven to the closed position. When the exhaust brake valve 12 is closed, the exhaust pipe 10 is fully closed or the exhaust passage area is reduced to an opening close to the fully closed state, and a well-known exhaust brake effect is produced.

Next, when the vehicle shifts from the engine brake running state to the normal running state, at least one of the clutch switch 34 and the accelerator switch 36 is opened, so that the solenoid valve 28 is deenergized and the solenoid valve 28 is opened. 28 returns to the rest or inoperative state shown in FIG. Therefore,
The compressed air supplied to the lower chamber of the piston of the actuator 18 passes from the output side passage 54 to the first chamber 56 and the vent hole 6.
0, the second chamber 58, and the atmosphere release passage 62, and is released to the outside air. The spring force of the return spring 26 causes the piston 22 to move downward, and the exhaust brake valve 12 passes through the piston shaft 24 and the valve opening / closing rod 14. 4 is rotated to the rest position or the fully open position shown in FIG.

At this time, in the conventional solenoid valve 18, the effective passage area formed between the vent hole 60 and the valve shaft 50 inserted therein is extremely small, so that the compressed air is discharged from the actuator 18. Need time to complete,
It takes a considerable time, for example, about 0.3 seconds, until the exhaust brake valve 12 is fully opened. This will now be described with reference to the diagram of FIG. 7. The uppermost line A in the figure shows ON-OFF of the solenoid 44 of the solenoid valve 28, the middle line B shows the compressed air pressure in the actuator 18, The lower line C shows the closed state of the exhaust brake valve 12, and the horizontal axis is time (Sec) in each case. First, when the energization to the solenoid 44 is cut off at the point 0 indicated by the arrow on the line A, the pressure in the lower chamber of the piston of the actuator 18 changes to the operating pressure as shown by the curve B of the middle solid line. Atmospheric pressure P ₀ requires a certain time, for example, about 0.3 seconds, from P _1.
Or, it drops to a low pressure close to it. Actuator 1
Curve C in the figure accompanying the pressure drop in the piston lower chamber of No. 8
As shown in, the exhaust brake valve 12 starts to open from point C ₁ with a slight delay, and the exhaust brake valve 12 becomes fully open at point C ₂ .

As described above, since it takes a long time from the de-energization of the solenoid valve 28 to the full opening of the exhaust brake valve 12, a sufficient exhaust passage area is secured when the engine brake traveling state is ended and the vehicle is accelerated. Without combustion, exhaust gas performance, especially smoke performance, deteriorates. This will now be described with reference to FIG. 8. In the figure, the uppermost curve D indicates the accelerator opening, the dashed-dotted curve E indicates the exhaust pressure in the exhaust pipe 10, and the corrugated curve F indicates the smoke amount of exhaust gas. Show. Figure 7
Similarly to the above, at the 0 point indicating the deactivation of the solenoid valve 28, the accelerator pedal is largely depressed for acceleration, and the accelerator opening is maintained at a preset opening. Since the opening of the exhaust brake valve 12 is delayed as described above, the exhaust pressure in the exhaust pipe 10 is delayed and decreased as shown by the curve E. Although the fuel supply amount immediately increases due to the increase in the accelerator opening, the pressure drop in the exhaust pipe 10 is delayed, so that the combustion deteriorates and a large amount of smoke is generated as shown by the curve F.

In order to improve the above-mentioned problems in the conventional exhaust brake device, the cross-sectional area of the vent hole 60 of the solenoid valve 28 shown in FIGS. 5 and 6 is increased so that the solenoid valve 28 is extinguished. It suffices if the compressed air in the lower chamber of the piston of the actuator 18 flows out to the outside quickly when the actuator 18 is energized. However, if the cross-sectional area of the vent hole 60 is simply increased, the diameter of the valve member 48 is correspondingly increased. Since it is necessary to secure the area of the sealing surface, the necessary spring force of the valve spring 64 for pressing down the valve member 48 to the rest position against the compressed air pressure in the first chamber 56 in the state of FIG. 6 is large. In addition, since it is necessary to increase the capacity of the solenoid 44 that moves the valve member 48 upward against the spring force of the valve spring 64, the solenoid valve 28 as a whole becomes remarkably large, and the weight and power consumption are reduced. Increase There is a disadvantage to be expensive together.

As another method for solving the above-mentioned problems in the conventional exhaust brake device, the actuator 18 itself operates in conjunction with the solenoid valve 28 to generate a large exhaust gas for discharging compressed air in the actuator. Although it is considered to attach a special valve device that provides a passage,
Attaching a valve dedicated to exhaust to the actuator 18 which is arranged adjacent to the exhaust pipe 10 and is exposed to high temperature by nature is
There is a problem of lack of practicality due to the problem of durability of the rubber member used for the valve member and the valve molding part which cooperates, and it is necessary to provide a valve for exclusive use of exhaust separately from the solenoid valve, resulting in high cost. There is inconvenience.

[0013]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and effectively suppresses the generation of black smoke when the operation of the exhaust brake device is deactivated, thereby achieving an improvement in exhaust gas performance. An object of the present invention is to provide a solenoid valve for an exhaust brake that has a simple structure, is small, lightweight, and is inexpensive.

[0014]

In order to achieve the above object, the present invention is connected to an input side passage connected to a pressure passage communicating with a pressure source and a pressure passage communicating with an exhaust brake driving actuator. An output-side passage, a first chamber in which the input-side passage and the output-side passage open, and a first chamber having a larger cross-sectional area than the first chamber and the first-chamber opening of the input-side passage.
A second chamber communicating with the opening, an atmosphere opening passage communicating the second chamber with the outside air, a first valve member provided in the first chamber for opening and closing the first opening, and provided in the first chamber The elastic member for urging the first valve member in the opening direction, and the elastic member provided on the first valve member for communicating the first chamber and the second chamber when the first valve member is in the closed position. The input side passage fixed to the tip of a shaft extending through a second opening having a smaller cross-sectional area than the first opening and the second opening fixed to an armature driven by an electromagnet installed in the second chamber. And a second valve member that opens and closes the second opening, and proposes an electromagnetic valve for an exhaust brake.

[0015]

According to the present invention, the first opening having a large cross-sectional area for communicating the first chamber and the second chamber is provided separately from the second valve member for controlling the communication between the input side passage and the output side passage. By providing the first valve member for opening and closing the first valve member and further providing the elastic member for urging the first valve member in the opening direction at all times, the discharge of the pressure fluid from the actuator is mainly performed with a large sectional area.
Since it is performed from the opening through the second chamber and the atmosphere opening passage, the response when the actuator is deenergized is significantly improved.

[0016]

Embodiments of the present invention will be specifically described below with reference to FIGS. (Note that members that are substantially the same as or correspond to those of the conventional exhaust brake device are denoted by the same reference numerals, and redundant description will be omitted.) As shown well in the cross-sectional views of FIGS. 1 to 3. In the electromagnetic valve generally indicated by reference numeral 28, a casing main body 42a, a lower casing member 42b fixed to the casing main body 42a by bolts and the like, and a hollow cylindrical portion formed in the casing main body 42a. A valve casing 4 including a cap member 42c screwed into the upper end opening.
It has 2.

A first chamber or a valve chamber 56 is formed by the casing body 42a and the lower casing member 42b, and an input connected to the compressed air source 30 via a pressure passage or an air pipe is formed in the first chamber 56. The side passage 52 communicates with an output side passage 54 connected to the piston lower chamber of the actuator 18 via a pressure passage or an air pipe. Further, in the casing body 42a, a solenoid 44 is inserted into the hollow cylindrical portion thereof and a second chamber or armature chamber 58 is formed therein, and an armature or an iron core driven by the solenoid 44 is provided in the second chamber 58. 46 and a valve spring 64 formed of an elastic member, such as a coil spring, for constantly pressing the armature downward.
Is provided.

The first chamber 56 and the second chamber 58 are communicated with each other by a first opening 66 having a sectional area sufficiently larger than the opening area of the input side passage 52 with respect to the first chamber 56. The armature 46 has a valve shaft or shaft 5
The small-diameter second valve member 48 is attached through
The valve member 48 can control the opening / closing of the opening end of the inlet side passage 52 in the first chamber 56 by the lower sealing surface thereof. In addition, the first opening 66 and the second valve member 48.
And a disc-shaped first valve member 70 having a second opening 68 having a small cross section through which the valve shaft or the shaft is inserted, and the first valve member 70 has the above-mentioned first sealing member due to its upper sealing surface. The one opening 66 can be closed airtightly. Furthermore, the first
The valve member 70 is constantly urged in a direction to open the first opening 66 by an elastic member 72 formed of, for example, a coil spring, and the second valve member 48 has a first sealing surface of the first opening 66 that prevents the first opening 66 from opening. The opening end on the chamber 56 side can be controlled to be opened and closed.

FIG. 1 shows a state in which the vehicle is in the engine brake running state and the solenoid valve 28 is energized. The energization of the solenoid 44 causes the armature 46 to compress the valve spring 64 and displace upward. . At this time, the second valve member 48 integrally moves upward via the valve shaft or the shaft 50, and the upper sealing surface thereof abuts the lower side surface of the first valve member 70 to close the second opening 68 and the first opening 68. The valve member 70 is pushed up, and the large-diameter first opening 66 is closed by the upper sealing surface of the first valve member. On the other hand, the second valve member 4
Due to the upward movement of 8, the input side passage 52 communicates with the outlet side passage 54 via the first chamber 56. Therefore, the compressed air source 3
Compressed air in 0 is supplied to the piston lower chamber of the actuator 18, the return spring 26 is compressed, and the exhaust brake valve 12 is fully closed or rotated to an opening degree close to it via the piston shaft 24 and the valve opening / closing rod 14. The well-known exhaust brake effect is produced.

When the vehicle finishes engine braking and accelerates, the solenoid 44 of the solenoid valve 28 is deenergized, so that the armature 46 is pressed down by the strong spring force of the valve spring 64 and the valve shaft or shaft 50. The second valve member 48 moves downward via the valve, and the input side passage 52 is instantaneously closed by the lower sealing surface thereof. At this time, the first chamber 56
Since compressed air having substantially the same pressure as that of the lower chamber of the piston of the actuator 18 exists in the second chamber 58 and the first chamber 5 communicating with the outside air via the atmosphere opening passage 62.
The elastic member 72 is compressed due to the pressure difference between the first valve member 70 and the first valve member 70, and as shown in FIG.

In the state of FIG. 2, the compressed air in the first chamber 56 flows through the passage between the second opening 68 and the valve shaft or the shaft 50 to the second chamber 58, so that the first chamber 56 and the second chamber 56. The pressure difference with 58 is immediately eliminated and the elastic device 72 allows the first
The valve member 70 is displaced downward to open the large opening first opening 66, as shown in FIG. Therefore, the output side passage 54 and the atmosphere opening passage 62 are communicated with each other through the wide first opening 66, and the compressed air rapidly flows out from the piston lower chamber of the actuator 18.

As a result, as indicated by the dotted line b in the curve B of FIG. 7 showing the pressure in the lower chamber of the piston of the actuator 18, the actuator operating pressure sharply decreases from P ₁ to P ₀ at about atmospheric pressure. To do. Therefore, the piston 22 of the actuator 18 is rapidly displaced by the return spring 26, and the piston shaft 24 and the valve opening / closing rod 1
4, the exhaust brake valve 12 is a conventional exhaust gas valve shown by a solid line, as shown by a curve C in FIG. 7 at a point C ₃ (opening operation start) and a point C ₄ (opening operation end fully open). It is fully opened earlier than the brake system.

Since the opening operation of the exhaust brake valve 12 is performed sufficiently early, the exhaust pipe 10 shown by the curve E in FIG.
The pressure in the inside of the exhaust gas decreases rapidly and early as indicated by the dotted line e, and as a result, the amount of smoke in the exhaust gas becomes a curve F indicating the conventional amount of smoke as indicated by the dotted line f. There is an advantage that it is greatly reduced compared to.

Since the solenoid valve 28 according to the present invention substantially corresponds to the conventional solenoid valve of the same type with the addition of the first valve member 66 and the elastic member 72, the outer shape and weight of the entire valve and the manufacturing cost are remarkably increased. There is no increased penalty and the solenoid valve 28 can be arranged far enough away from the actuator 18 exposed to high temperatures that the first and second valve members 4
8 and 70 valve sealing surfaces and cooperating valve casing 4
Either one or both of the two valve sealing surfaces has a gain that can reliably prevent heat damage of a sealing material such as rubber that is usually employed, and can ensure durability and reliability.

In the above embodiment, the actuator 1
As the working medium of No. 8, generally used compressed air is illustrated, but it is obvious that a pressurized fluid other than compressed air can be used.

[0026]

As described above, the solenoid valve for exhaust brake according to the present invention is connected to the input side passage connected to the pressure passage communicating with the pressure source and the pressure passage communicating with the exhaust brake driving actuator. An output side passage, a first chamber in which the input side passage and the output side passage are opened, and a first chamber having a larger cross-sectional area than the first chamber and the first chamber opening of the input side passage.
A second chamber communicating with the opening, an atmosphere opening passage communicating the second chamber with the outside air, a first valve member provided in the first chamber for opening and closing the first opening, and provided in the first chamber An elastic member for urging the first valve member in the opening direction; and a first elastic member provided on the first valve member for communicating the first chamber with the second chamber when the first valve member is in the closed position. A second opening having a cross-sectional area smaller than that of the first opening; a second end fixed to an armature driven by an electromagnet installed in the second chamber; A structure that has a second valve member that opens and closes the second opening, and is capable of effectively suppressing the generation of black smoke immediately after the operation of the exhaust brake device is deactivated and improving exhaust gas performance. We offer this type of solenoid valve that is simple, compact, lightweight, and inexpensive Therefore, it is industrially beneficial.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a mode of energizing a solenoid valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state immediately after the solenoid valve shown in FIG. 1 is deenergized.

FIG. 3 is a cross-sectional view showing a mode after a short time has elapsed after the solenoid valve shown in FIG. 1 was deenergized.

FIG. 4 is a schematic configuration diagram showing an overall configuration of an exhaust brake device.

FIG. 5 is a schematic cross-sectional view showing a mode of a conventional exhaust brake solenoid valve when deenergized.

FIG. 6 is a schematic cross-sectional view showing a mode when the solenoid valve shown in FIG. 5 is energized.

FIG. 7 is a diagram showing a relationship between energization and deenergization of an electromagnetic valve for an exhaust brake, working medium pressure of an actuator, and an opening of an exhaust brake valve.

FIG. 8 is a diagram showing a relationship between energization and deenergization of an exhaust brake solenoid valve, an accelerator opening, an exhaust pipe internal pressure, and a smoke generation amount.

[Explanation of symbols]

10 ... Exhaust pipe, 12 ... Exhaust brake valve, 18 ... Actuator, 28 ... Electromagnetic valve, 30 ... Compressed air source (pressure source),
42 ... Valve casing, 44 ... Solenoid, 46 ... Armature, 48 ... Second valve member, 50 ... Valve shaft (shaft), 5
2 ... Input side passage, 54 ... Output side passage, 56 ... First chamber, 5
8 ... Second chamber, 62 ... Atmosphere opening passage, 66 ... First opening, 6
8 ... 2nd opening, 70 ... 1st valve member, 72 ... Elastic member.

Claims (1)

[Claims] 1. An input-side passage connected to a pressure passage communicating with a pressure source, an output-side passage connected to a pressure passage communicating with an exhaust brake driving actuator, and the input-side passage and the output-side passage. A first chamber having an opening, and a first chamber having a larger cross-sectional area than the first chamber opening of the first chamber and the input side passage.
A second chamber communicating with the opening, an atmosphere opening passage communicating the second chamber with the outside air, a first valve member provided in the first chamber for opening and closing the first opening, and provided in the first chamber An elastic member for urging the first valve member in the opening direction; and a first elastic member provided on the first valve member for communicating the first chamber with the second chamber when the first valve member is in the closed position. A second opening having a cross-sectional area smaller than that of the first opening; a second end fixed to an armature driven by an electromagnet installed in the second chamber; An exhaust brake electromagnetic valve, comprising: a second valve member that opens and closes the second opening.