JPH0223805Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a protection device for equipment operated by negative intake pressure in a turbocharged internal combustion engine.

[Conventional technology]

In the control circuit of an internal combustion engine, there is an EGR valve that is activated by negative pressure in the intake pipe, such as an EGR valve.
There is a device that controls the rate.

[The problem that the idea aims to solve]

By the way, the EGR valve is a device that operates sensitively due to negative pressure, and if large positive pressure is applied to this device, it may be destroyed or destroyed.
Otherwise, there is a risk of malfunction.

On the other hand, if negative pressure is always acting on the intake pipe of this internal combustion engine, there will be no problem with the operation of negative pressure operated devices such as the EGR valve, but as a measure to increase the output of this internal combustion engine, turbo charge is When equipped with a tire, large positive pressure acts on the intake pipe when the engine is under high load.

The EGR valve uses a diaphragm as an actuator and is designed to be operated by negative pressure in the intake pipe, so if large positive pressure acts on the intake pipe, there is a risk of damaging the actuator. However, it also has the drawback of causing malfunction even if it does not cause damage.

That is, since the diaphragm is formed of a flexible membrane, it usually has a shape bent toward the negative pressure side. However, when the pressure changes to positive pressure, the diaphragm, which has been bent as described above, is pushed out to the opposite side and assumes an inverted shape. If this is repeated, unreasonable stress will be applied to the diaphragm, leading to problems with durability.

Therefore, there is an idea proposed in Japanese Utility Model Application Laid-Open No. 56-43456, in which an inversion prevention member is provided which is a backing plate shaped like a diaphragm so that the diaphragm does not invert even when positive pressure is applied to the negative pressure chamber. However, since the anti-reversal member is mounted close to the pressure receiving plate, there is a risk of interfering with the smooth operation of the diaphragm, so it is still not sufficient for internal combustion engines for vehicles that experience strong vibrations.

The present invention was developed by focusing on the above problem, and when positive pressure is applied to the intake passage, such as in an internal combustion engine equipped with a turbocharger, the positive pressure is cut off and the diaphragm chamber is It is an object of the present invention to provide a protection device for negative pressure operating equipment of an internal combustion engine, which prevents transmission of positive pressure.

[Means to solve the problem]

The structure of the protection device for negative pressure operated equipment of an internal combustion engine according to the present invention to achieve the above object is to provide a protection valve between the negative pressure operated equipment and the intake passage, and this protection valve is connected to the negative pressure operated equipment. connection to the equipment,
It is constituted by a valve chamber having a negative pressure port and an atmosphere port that communicate with the intake passage side, and a piston valve that opens and closes the negative pressure port and the atmosphere port to selectively communicate with the communication port. The piston valve is driven by electromagnetic force toward the negative pressure port when the output signal of the pressure sensor attached to the intake passage is a positive pressure signal, and is driven toward the atmospheric port when the output signal is a negative pressure signal. It is something.

As the pressure detection means, a pressure sensor, a pressure switch, etc. can be used.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an outline of a protection device for an internal combustion engine according to the present invention, in which intake air A is pressurized by a compressor 3 of a turbocharger 2 driven by the exhaust gas of an internal combustion engine 1. The air is supplied to the intake manifold of the internal combustion engine 1 via the common chamber 4 that constitutes the intake passage of this embodiment.

Reference numeral 9 denotes an EGR valve, which is connected to the common chamber 4 through a control line 7 and is controlled by intake negative pressure. 6 is the control pipe 7
As shown in FIG. 2, valve seats 6b and 6c are provided inside the main body 6a.
A valve body 6d in contact with the valve seats 6b and 6c is operated by a solenoid coil 6e. One side of the main body 6a has a negative pressure port 6f connected to the control pipe 7.
A communication port 6g connected to the EGR valve 9 and an atmospheric port 6h communicating with the atmosphere are provided.

5 is a pressure sensor (or pressure switch) that detects the pressure of the intake system including the common chamber 4;
The solenoid coil 6e is disposed in the wiring connecting the solenoid coil 6e of the protection valve 6 and the power source 10, and is energized when the intake system pressure is above a predetermined pressure, for example, near atmospheric pressure. There is.

Reference numeral 8 denotes a thermo-vacuum valve disposed in the control pipe 7, which opens when the temperature of engine cooling water exceeds a predetermined temperature and closes when the temperature drops below a predetermined temperature.

In this embodiment, the EGR valve 9 is used as an example of the device that operates with negative intake pressure, but the present invention is not limited to this, and may be used, for example, with a distributor, a signal cutter of a vacuum advancer, It can be applied to negative pressure operated equipment related to the signal cut of the secondary air switching valve.

Next, the operation of the apparatus according to the present invention will be explained.

When the internal combustion engine 1 is under low load, the intake system is in a negative pressure state and the protection valve 6 is not operated, resulting in the state shown in FIG. 2. Therefore, when the engine cooling water temperature is above a predetermined value, intake pipe negative pressure acts on the EGR valve 9 via the thermo-vacuum valve and the cut valve 6, and EGR control is performed in accordance with this negative pressure.

Next, when the internal combustion engine 1 enters a high load state, the supercharging pressure of the turbocharger 2 increases, and the pressure in the intake system including the common chamber 4 increases.

When the pressure within this common chamber 4 becomes higher than a specified value, for example, higher than atmospheric pressure, the pressure sensor 5 is turned on, and the solenoid coil 6e of the protection valve 6 is energized to operate the protection valve 6. This protection valve 6 is a 3-way valve as shown in Fig. 2, and by moving the valve body 6d in the direction of arrow M, the negative pressure port 6f is closed and the pressure in the control pipe 7 is reduced. Prevent it from acting on EGR valve 9.

On the other hand, by moving the valve body 6d in the direction of the arrow M, the atmosphere port 6h and the communication port 6g are brought into communication, and the actuator of the EGR valve 9 is brought into an open state to the atmosphere. In this way, when the boost pressure increases when the engine is under high load, the intake system pressure does not act on the EGR valve 9, which is controlled by the intake negative pressure, so a large pressure acts on the EGR valve 9. This can prevent damage or malfunction.

[Effects of the invention] As explained above, in the protection device for negative pressure operating equipment of an internal combustion engine of the present invention, the valve surface of the piston valve provided in the protection valve is provided in the axial direction, so that the intake pressure becomes positive pressure. When the pressure sensor detects this and the piston valve moves to open the atmosphere port, the atmosphere can be immediately introduced into the valve chamber to protect the negative pressure operating equipment.

Therefore, for any negative pressure operated equipment,
It is possible to prevent destruction or malfunction due to the action of positive pressure.

Therefore, in recent years, turbochargers have often been installed as part of measures to improve the output of internal combustion engines, but even in such cases, conventional negative pressure operating equipment can be used as is. This makes it possible to share parts with internal combustion engines that are not equipped with a turbocharger.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view showing essential parts of a protection device for negative pressure operating equipment in an internal combustion engine according to the present invention, and FIG. 2 is a sectional view of a protection valve used in the protection device. 1... Internal combustion engine, 2... Turbocharger, 3...
Compressor, 4... Common chamber, 5... Pressure sensor, 6... Protection valve, 6b, 6c... Valve seat, 6d
...Valve body, 6e...Solenoid coil, 6f...Negative pressure port, 6g...Connection port, 6h...Atmospheric port, 7...Control line, 9...EGR valve.

Claims (1)

[Scope of utility model registration request] A protection valve is provided between the negative pressure operating device and the intake passage, and the protection valve is connected to a valve chamber having a communication port communicating with the negative pressure operating device, a negative pressure port communicating with the intake passage side, and an atmosphere port; It is composed of a piston valve that selectively opens and closes a negative pressure port and an atmosphere port to communicate with the communication port, and the piston valve is operated by an electromagnetic force to generate an output signal of a pressure sensor attached to the intake passage. . A protection device for a negative pressure operating device of an internal combustion engine, which is driven toward the negative pressure port side when a positive pressure signal is received, and driven toward the atmospheric port side when a negative pressure signal is received.