JPS6319557Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a negative pressure transmission device for a supercharged engine, and in particular, a negative pressure transmission passage for operating a pressure responsive member in an intake passage downstream of a turbocharger and a fuel supply device. This invention relates to a measure against fuel leakage from the three-way solenoid valve in a three-way solenoid valve which is opened and a three-way solenoid valve is interposed in the negative pressure transmission passage.

Conventionally, in engines equipped with a supercharger for supercharging intake air into the intake passage of the engine and a fuel supply device for supplying fuel downstream of the supercharger, there has been an exhaust gas recirculation device, an ignition advance device, etc. When performing control, a negative pressure transmission passage for transmitting the intake negative pressure of the intake passage downstream of the fuel supply device is provided, and a pressure responsive device such as a diaphragm type or a piston type that responds to the intake negative pressure is installed in the negative pressure transmission passage. and switching between the opening of the negative pressure transmission passage to the intake passage and the pressure responsive member to introduce negative intake pressure or atmospheric air into the pressure responsive member depending on the operating state of the engine. By interposing a three-way solenoid valve to control
It is well known to control the operation of the exhaust gas recirculation device and the like by controlling the operation of a pressure-responsive member by switching a three-way solenoid valve depending on the operating state of the engine.

However, in the above-mentioned conventional system, when the three-way solenoid valve is in the atmosphere introduction switching position, which deactivates the exhaust gas recirculation device, etc., the turbocharger does not allow the valve body to close the intake passage communication port of the three-way solenoid valve to be supercharged. Pressure (positive pressure) acts, and this positive pressure pushes the valve body open against the biasing force of the spring or the electromagnetic force of the solenoid, and as a result, the fuel in the intake passage flows into the atmosphere from the atmosphere opening port of the three-way solenoid valve. In the case of a diaphragm type, the rubber diaphragm deteriorates due to contamination, and in the case of a piston type, the piston is similarly pushed open, causing fuel to leak out. Ta.

In addition, in conventional engines without a supercharger, as disclosed in Japanese Utility Model Application Publication No. 57-37610, the atmosphere opening of a three-way solenoid valve interposed in the negative pressure transmission passage was used as an air cleaner in the intake passage. By connecting between the throttle valve and introducing air purified by the air cleaner into the three-way solenoid valve when the three-way solenoid valve is in the atmosphere introduction switching position, a filter in the three-way solenoid valve is not required. Although a device has been proposed that does this, it does not provide any solution to the above-mentioned problem (fuel leakage from the three-way solenoid valve).

Therefore, in view of this point, the present invention has been developed in a negative pressure transmission device for an engine equipped with a supercharger as described above, in which the negative pressure acting on the valve body of the three-way solenoid valve is reduced when the three-way solenoid valve is in the atmosphere introduction switching position. By introducing positive pressure that opposes positive pressure (supercharging pressure) into the three-way solenoid valve from the transmission passage, the valve body reliably keeps the intake passage communication port closed and opens the three-way solenoid valve to the atmosphere. The purpose of this is to prevent fuel from leaking into the atmosphere from the mouth and from staining the pressure-responsive member.

In order to achieve this object, the configuration of the present invention includes a supercharger provided in an intake passage for supercharging intake air, and a fuel supply provided in the intake passage downstream of the supercharger for supplying fuel. a supply device, a negative pressure transmission passage for transmitting the intake negative pressure of the intake passage downstream of the fuel supply device, a pressure responsive member connected to the negative pressure transmission passage and responsive to the intake negative pressure, and the negative pressure A three-way solenoid valve is interposed between the opening of the transmission passage to the intake passage and the pressure-responsive member, and is switched and controlled to introduce negative intake pressure or atmospheric air into the pressure-responsive member depending on the operating state of the engine. In a supercharged engine equipped with a supercharged engine, by connecting the atmosphere opening port of the three-way solenoid valve to the intake passage between the supercharger and the fuel supply device, when the three-way solenoid valve is in the atmosphere introduction switching position, the three-way solenoid valve A supercharging pressure (positive pressure) without fuel is introduced into the interior from the atmosphere opening port, and the supercharging pressure from the negative pressure transmission passage acting on the valve body of the three-way solenoid valve is balanced against the supercharging pressure, and the intake air by the valve body is This ensures that the passageway communication port remains closed.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

The figure shows an embodiment in which the present invention is applied to an exhaust gas recirculation system for an engine equipped with a turbocharger. 1 is an engine, 2 is an intake passage for supplying intake air to the engine 1, and 3 is an exhaust gas from the engine 1. An exhaust passage 4 is provided in the intake passage 2 and is a throttle valve for controlling the amount of air taken into the engine 1.

5 is a turbine 5a disposed in the exhaust passage 3;
and a blower 5b disposed upstream of the throttle valve 4 in the intake passage 2 and connected to the turbine 5a via a connecting shaft 5c, and the turbine 5a is rotated by the exhaust flow. The blower 5b is rotationally driven by the rotation of the turbine 5a, and supercharges the engine 1 with intake air through the intake passage 2.

Further, 6 is a fuel injection valve disposed upstream of the throttle valve 4 of the intake passage 2 and downstream of the blower 5b of the turbocharger 5, and 7 is a fuel injection control circuit for controlling the fuel injection amount of the fuel injection valve 6. , 8 is an air flow sensor for detecting the amount of intake air upstream of the blower 5b in the intake passage 2, and the detection signal of the air flow sensor 8 is input to the fuel injection control circuit 7, so that the amount of intake air is A fuel injection type fuel supply device 9 is configured to inject and supply the corresponding fuel from the fuel injection valve 6 to the intake passage 2.

On the other hand, 10 is an exhaust gas recirculation device for recirculating a part of the exhaust gas from the exhaust system to the intake system. It opens into the exhaust passage 3, and the other end of the exhaust recirculation port 10b opens downstream of the throttle valve 4 of the intake passage 2, that is, downstream of the blower 5b of the turbocharger 5 and the fuel supply device 9 (fuel injection valve 6). . A recirculation control valve 11 is interposed in the middle of the exhaust gas recirculation passage 10 to control the opening and closing of the exhaust gas recirculation passage 10 to control the amount of exhaust gas recirculation.

The recirculation control valve 11 is a pressure-responsive member whose operation is controlled using intake negative pressure as an operating source, and includes a shaft-shaped valve body 11a that opens and closes a valve seat 10c provided in the exhaust gas recirculation passage 10, and the valve body 11a. A diaphragm 11c that connects and supports the other end (the upper end in the figure) of the valve body 11a, and a valve defined vertically in the figure by the diaphragm 11c. Atmospheric pressure chamber 11d on the body 11a side (lower side) and the opposite side (upper side)
a negative pressure chamber 11e, and a spring 11 compressed within the negative pressure chamber 11e and urging the valve body 11a in the valve closing direction.
f, and the negative pressure chamber 11e has one end opened immediately upstream of the fully closed position of the throttle valve 4 of the intake passage 2 downstream of the blower 5b of the turbocharger 5 and the fuel supply device 9. A negative pressure transmission passage 12 for transmitting intake negative pressure is connected in communication,
When the engine 1 is operating other than idling, the intake negative pressure generated downstream of the throttle valve 4 is introduced into the negative pressure chamber 11e via the negative pressure transmission passage 12, thereby causing the diaphragm 11c to
The valve body 11a is biased upward in the figure against the biasing force 1f to open the valve body 11a, thereby opening the exhaust gas recirculation passage 10 and performing exhaust gas recirculation.

Further, an atmosphere opening port 12a is provided in the middle of the negative pressure transmission passage 12, and a pressure regulating device 13 for controlling the operation of the recirculation control valve 11 according to the exhaust pressure is disposed in the atmosphere opening port 12a. There is. The pressure regulator 13 includes a valve body 13a that opens and closes the atmosphere opening 12a, a diaphragm 13b that supports the valve body 13a, and an exhaust pressure chamber 13c and an atmospheric pressure chamber 13d defined by the diaphragm 13b. and a spring 13e that is compressed in the atmospheric pressure chamber 13d and biases the valve body 13a in the valve opening direction. 11 (valve body 11a) is communicated upstream, and the atmospheric pressure chamber 13d is exposed to the atmosphere opening 12a, and the atmospheric pressure chamber 13d is connected to the atmosphere through a communication path 16 with a filter member 15 interposed therebetween. It is communicated. And exhaust recirculation passage 1
When the pressure (exhaust pressure) on the upstream side of the reflux control valve 11 increases, the diaphragm 13b is biased upward in the figure against the biasing force of the spring 13e due to the increase in pressure in the exhaust pressure chamber 13c, and the valve body 13a is forced to release the air to the atmosphere. By closing the opening 12a, the reflux control valve 1
The intake negative pressure is directly introduced into the negative pressure chamber 11e without being diluted with the atmosphere, and the recirculation control valve 11 is opened to perform exhaust gas recirculation. As a result, the pressure (exhaust pressure) on the upstream side of the recirculation control valve 11 decreases,
Due to this pressure drop, the diaphragm 13b is biased downward by the biasing force of the spring 13e, and the valve body 13a opens the atmosphere release port 12a, whereby the intake negative pressure acting on the negative pressure chamber 11e of the recirculation control valve 11 is transferred to the filter member. The air is diluted by the air flowing in from the air opening 12a through the air opening 15. As a result, the reflux control valve 11 closes, and the pressure (exhaust pressure) on the upstream side of the reflux control valve 11 increases again. This operation is repeated to keep the exhaust pressure almost constant, and Therefore, the exhaust gas recirculation rate is controlled to be substantially constant with respect to the exhaust pressure, that is, the amount of air taken into the engine 1.

Further, between the opening of the negative pressure transmission passage 12 to the intake passage 2 and the atmosphere opening port 12a, a recirculation control valve 11 as a pressure-responsive member is installed depending on the operating state of the engine (for example, engine cooling water temperature). A three-way solenoid valve 17 is provided for switching control to introduce negative intake pressure or atmospheric air into the negative pressure chamber 11e. The three-way solenoid valve 17 has an intake passage communication port 17a, a negative pressure chamber communication port 17b, and an atmosphere release port 17c, and a valve body that selectively opens and closes the intake passage communication port 17a and the atmosphere release port 17c. 17b
and a spring 17e that biases the valve body 17d in a direction to close the intake passage communication port 17a, and when energized, the valve body 17d is electromagnetically attracted to close the atmosphere opening port 17c against the biasing force of the spring 17e. For example, when the solenoid 17f with a high engine cooling water temperature is energized, the valve body 17d closes the atmosphere opening port 17c, and the intake passageway communication port 17a and the negative pressure chamber communication port 17b communicate with each other. As a position, the intake negative pressure from the intake passage 2 is passed through the negative pressure transmission passage 12 to the recirculation control valve 1.
By introducing the recirculation control valve 11 into the negative pressure chamber 11e of No. 1, the recirculation control valve 11 is activated to perform exhaust gas recirculation, while the valve element 17d closes the intake passage communication port 17a when the solenoid 17f is not energized due to low engine cooling water temperature.
The atmosphere opening port 1 is used as an atmosphere introduction switching position where the atmosphere opening port 17c and the negative pressure chamber communication port 17b communicate with each other.
By introducing atmospheric air from 7c into the negative pressure chamber 11e, the recirculation control valve 11 is brought into a non-operating state and exhaust gas recirculation is stopped.

As a feature of the present invention, in the three-way solenoid valve 17, the atmosphere opening port 17c is connected to the communication path 1.
8 is connected to the intake passage 2 between the blower 5b of the turbocharger 5 and the fuel supply device 9, and when the three-way solenoid valve 17 is in the atmosphere introduction switching position, the air is released from the atmosphere opening port 17c. The fuel supply device 9 is provided downstream of the blower 5b of the turbocharger 5 instead of the atmosphere.
The pressure of the upstream intake passage 2 is introduced.

Note that the atmospheric pressure chamber 11d of the recirculation control valve 11 is connected to the turbine 5a of the turbocharger 5 via a communication passage 19.
It communicates with the downstream exhaust passage 3, and the exhaust gas in the exhaust recirculation passage 10 is connected to the valve body 11a and the housing 11b.
Even if the gas leaks into the atmospheric pressure chamber 11d from between the two, it is purified by a catalyst device (not shown) provided in the exhaust passage 3.

Therefore, in the above embodiment, when the three-way solenoid valve 17 is in the intake negative pressure introduction switching position, the intake passage communication port 17a and the negative pressure chamber communication port 17b of the three-way solenoid valve 17 communicate with each other, and the atmosphere opening port 17c is in communication with the negative pressure chamber communication port 17b. Due to the blockage, the intake negative pressure generated in the intake passage 2 downstream of the blower 5b of the turbocharger 5 and the fuel supply device 9 is transferred to the recirculation control valve 1 via the negative pressure transmission passage 12.
1 negative pressure chamber 11e, and the reflux control valve 11
is opened and exhaust gas is recirculated. At this time, the operation of the recirculation control valve 11 is controlled by the pressure regulating device 13, so that the exhaust gas recirculation is controlled at a constant exhaust recirculation rate with respect to the amount of intake air.

On the other hand, when the three-way solenoid valve 17 is in the atmosphere introduction switching position, the atmosphere opening port 17c of the three-way solenoid valve 17 and the negative pressure chamber communication port 17b communicate with each other, and the intake passage communication port 1
By closing 7a, the reflux control valve 1
The pressure in the intake passage 2 downstream of the blower 5b of the turbocharger 5 and upstream of the fuel supply device 9, that is, the supercharging pressure (positive pressure) from the turbocharger 5, is connected to the communication port 18 and the negative pressure chamber 11e of the Since the exhaust gas is introduced through the pressure transmission passage 12, the recirculation control valve 11 is closed and the exhaust gas recirculation is stopped. At that time, in the three-way solenoid valve 11, the valve body 17 that closes the intake passage communication port 17a
The supercharging pressure containing fuel from the negative pressure transmission passage 12 acts on the valve d, but the supercharging pressure introduced into the three-way solenoid valve 17 from the atmosphere opening 17c counterbalances and counteracts the above-mentioned valve. The closed state of the intake passage communication port 17a by the body 17d is reliably maintained, thereby preventing fuel leakage into the atmosphere from the conventional three-way solenoid valve and contamination of the recirculation control valve 11 as a pressure-responsive member. It can be prevented.

Furthermore, the three-way solenoid valve 1 is connected to the atmosphere opening port 17c.
The supercharging pressure introduced into the fuel supply device 7 is the pressure of the intake passage 2 upstream of the fuel supply device 9 and does not include fuel.
This introduction of pressure into the three-way solenoid valve 17 does not cause the three-way solenoid valve 17 to become contaminated or cause fuel to leak from the pressure regulator 13 to the atmosphere. Moreover, since the supercharging pressure (positive pressure) is introduced into the negative pressure chamber 11e of the reflux control valve 11, the reflux control valve 11
This has the advantage that the closed operating state can be maintained more reliably.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, the present invention is applicable not only to the engine 1 equipped with the turbocharger 5 as in the above embodiment, but also to various supercharged engines, and also to fuel injection type fuel as in the above embodiment. In addition to the supply device 9, it is also applicable to a vaporizer type device.

Further, in the above embodiment, the negative pressure transmission passage 12 is opened immediately upstream of the fully closed position of the throttle valve 4 in the intake passage 2, but it may always be opened at a position downstream of the throttle valve 4. In the case of a container type, the opening may be made in the bench lily part.
In short, it is sufficient as long as it opens into the intake passage downstream of the supercharger and the fuel supply device and transmits the intake negative pressure.

Furthermore, it is also possible to adopt a three-way solenoid valve 17 that operates in the opposite manner to that of the above embodiment, that is, it is in the intake negative pressure introduction switching position when the solenoid 17f is energized, and is in the atmosphere introduction switching position when it is not energized.

Furthermore, although the above embodiment describes the case where it is applied to the exhaust gas recirculation system of a supercharged engine, the present invention is also applicable to various pressure-responsive applications such as negative pressure transmission to the vacuum advance mechanism of an ignition advance device. Needless to say, the present invention is also applicable to transmitting negative pressure to members.

As explained above, according to the present invention, the negative pressure transmission passage for operating the pressure responsive member is opened to the intake passage downstream of the turbocharger and the fuel supply device downstream of the turbocharger, and In a supercharged engine with a three-way solenoid valve interposed in the pressure transmission passage, by connecting the atmosphere opening port of the three-way solenoid valve to the intake passage between the supercharger and the fuel supply device, the atmosphere of the three-way solenoid valve can be removed. When in the introduction switching position, the valve body reliably maintains the closed state of the intake passage communication port to ensure and effectively prevent fuel leakage from the three-way solenoid valve to the atmosphere due to boost pressure and contamination of pressure-responsive members. It is preventable.

[Brief explanation of drawings]

The drawing is an overall schematic diagram showing an embodiment of the present invention. 1... Engine, 2... Intake passage, 5... Turbo supercharger, 5a... Turbine, 5b... Blower,
9...Fuel supply device, 10...Exhaust recirculation device, 1
1... Reflux control valve, 11e... Negative pressure chamber, 12...
Negative pressure transmission passage, 13... Pressure adjustment device, 17...
Three-way solenoid valve, 17a...Intake passage communication port, 17b
...Negative pressure chamber communication port, 17c...Atmospheric release port, 17
d... Valve body, 17e... Spring, 17f...
Solenoid, 18...Communication path.

Claims (1)

[Scope of utility model registration request] A supercharger provided in an intake passage for supercharging intake air, a fuel supply device provided in the intake passage downstream of the supercharger for supplying fuel, and a supercharger for supercharging intake air in the intake passage downstream of the fuel supply device. a negative pressure transmission passage for transmitting pressure; a pressure responsive member connected to the negative pressure transmission passage and responsive to intake negative pressure; and an opening of the negative pressure transmission passage to the intake passage and the pressure responsive member. In a supercharged engine equipped with a three-way solenoid valve that is interposed between the three-way solenoid valve and that controls switching so as to introduce negative intake pressure or atmospheric air into the pressure-responsive member depending on the operating state of the engine, the three-way solenoid valve A negative pressure transmission device for a supercharged engine, characterized in that an open port is connected to an intake passage between a supercharger and a fuel supply device.